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Sample records for cervical polyetheretherketone peek

  1. PEEK (Polyether-ether-ketone) Based Cervical Total Disc Arthroplasty: Contact Stress and Lubrication Analysis.

    PubMed

    Xin, H; Shepherd, Det; Dearn, Kd

    2012-01-01

    This paper presents a theoretical analysis of the maximum contact stress and the lubrication regimes for PEEK (Polyether-ether-ketone) based self-mating cervical total disc arthroplasty. The NuNec(®) cervical disc arthroplasty system was chosen as the study object, which was then analytically modelled as a ball on socket joint. A non-adhesion Hertzian contact model and elastohydrodynamic lubrication theory were used to predict the maximum contact stress and the minimum film thickness, respectively. The peak contact stress and the minimum film thickness between the bearing surfaces were then determined, as the radial clearance or lubricant was varied. The obtained results show that under 150 N loading, the peak contact stress was in the range 5.9 - 32.1 MPa, well below the yield and fatigue strength of PEEK; the calculated minimum film thickness ranged from 0 to 0.042 µm and the corresponding lambda ratio range was from 0 to 0.052. This indicates that the PEEK based cervical disc arthroplasty will operate under a boundary lubrication regime, within the natural angular velocity range of the cervical spine.

  2. PEEK (Polyether-ether-ketone) Based Cervical Total Disc Arthroplasty: Contact Stress and Lubrication Analysis

    PubMed Central

    Xin, H; Shepherd, DET; Dearn, KD

    2012-01-01

    This paper presents a theoretical analysis of the maximum contact stress and the lubrication regimes for PEEK (Polyether-ether-ketone) based self-mating cervical total disc arthroplasty. The NuNec® cervical disc arthroplasty system was chosen as the study object, which was then analytically modelled as a ball on socket joint. A non-adhesion Hertzian contact model and elastohydrodynamic lubrication theory were used to predict the maximum contact stress and the minimum film thickness, respectively. The peak contact stress and the minimum film thickness between the bearing surfaces were then determined, as the radial clearance or lubricant was varied. The obtained results show that under 150 N loading, the peak contact stress was in the range 5.9 – 32.1 MPa, well below the yield and fatigue strength of PEEK; the calculated minimum film thickness ranged from 0 to 0.042 µm and the corresponding lambda ratio range was from 0 to 0.052. This indicates that the PEEK based cervical disc arthroplasty will operate under a boundary lubrication regime, within the natural angular velocity range of the cervical spine. PMID:22670159

  3. Usefulness of polyetheretherketone (PEEK) cage with plate augmentation for anterior arthrodesis in traumatic cervical spine injury.

    PubMed

    Song, Kyung-Jin; Choi, Byung-Wan; Kim, Gyu-Hyung; Song, Ji-Hun

    2010-01-01

    Even though many clinical reports about cages have been documented in patients with degenerative disorders, reports were scarce for traumatic injury cases, and those cases using metal cages were restricted to only one-level injury. To evaluate the usefulness of polyetheretherketone (PEEK) cage and plate construction in anterior interbody fusions (AIF) for traumatic cervical spine injuries by analyzing radiographic changes and clinical outcomes. Retrospective study. Fifty-eight patients (91 levels) underwent cage and plate construction for treatment of traumatic cervical spine injury. The fusion rate, fusion time, changes of Cobb angle, subsidence rate, and adjacent level changes were assessed as a radiographic outcome. Clinical analysis includes the recovery rate on the American Spinal Injury Association (ASIA) impairment scale and the presence of the complications. We evaluated 58 patients (91 levels) who underwent surgery and had at least 24 months in follow-up study. Radiographic evaluation included the assessment of interbody fusion rate, fusion time, changes of Cobb angle, subsidence rate, and adjacent level changes. Clinical assessment was done by analyzing recovery state of ASIA impairment scale from preoperative period to the last follow-up and by evaluating complications. Fifty-four cases showed bony fusion within 3 months after the surgery. The mean Cobb angle between the vertebral bodies was 2.54 degrees before operation, 9.13 degrees after operation, and 8.39 degrees at the latest follow-up. The mean intervertebral disc height was increased by 3.01 mm after the operation, but the mean height was 2.17 mm shorter at the last follow-up than after postoperation. In terms of clinical results, five Grade A cases and one Grade B case as assessed by the ASIA impairment scale were unchanged until the last follow-up. Twenty-three cases of Grade C, 16 cases of Grade D, and 13 cases of Grade E improved to seven cases, 26 cases, and 19 cases, respectively. Three

  4. Subsidence and nonunion after anterior cervical interbody fusion using a stand-alone polyetheretherketone (PEEK) cage.

    PubMed

    Yang, Jae Jun; Yu, Chang Hun; Chang, Bong-Soon; Yeom, Jin Sup; Lee, Jae Hyup; Lee, Choon-Ki

    2011-03-01

    The purposes of the present study are to evaluate the subsidence and nonunion that occurred after anterior cervical discectomy and fusion using a stand-alone intervertebral cage and to analyze the risk factors for the complications. Thirty-eight patients (47 segments) who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage and an autologous cancellous iliac bone graft from June 2003 to August 2008 were enrolled in this study. The anterior and posterior segmental heights and the distance from the anterior edge of the upper vertebra to the anterior margin of the cage were measured on the plain radiographs. Subsidence was defined as ≥ a 2 mm (minor) or 3 mm (major) decrease of the segmental height at the final follow-up compared to that measured at the immediate postoperative period. Nonunion was evaluated according to the instability being ≥ 2 mm in the interspinous distance on the flexion-extension lateral radiographs. The anterior and posterior segmental heights decreased from the immediate postoperative period to the final follow-up at 1.33 ± 1.46 mm and 0.81 ± 1.27 mm, respectively. Subsidence ≥ 2 mm and 3 mm were observed in 12 segments (25.5%) and 7 segments (14.9%), respectively. Among the expected risk factors for subsidence, a smaller anteroposterior (AP) diameter (14 mm vs. 12 mm) of cages (p = 0.034; odds ratio [OR], 0.017) and larger intraoperative distraction (p = 0.041; OR, 3.988) had a significantly higher risk of subsidence. Intervertebral nonunion was observed in 7 segments (7/47, 14.9%). Compared with the union group, the nonunion group had a significantly higher ratio of two-level fusion to one-level fusions (p = 0.001). Anterior cervical fusion using a stand-alone cage with a large AP diameter while preventing anterior intraoperative over-distraction will be helpful to prevent the subsidence of cages. Two-level cervical fusion might require more careful attention for avoiding nonunion.

  5. Subsidence and Nonunion after Anterior Cervical Interbody Fusion Using a Stand-Alone Polyetheretherketone (PEEK) Cage

    PubMed Central

    Yang, Jae Jun; Yu, Chang Hun; Yeom, Jin Sup; Lee, Jae Hyup; Lee, Choon-Ki

    2011-01-01

    Background The purposes of the present study are to evaluate the subsidence and nonunion that occurred after anterior cervical discectomy and fusion using a stand-alone intervertebral cage and to analyze the risk factors for the complications. Methods Thirty-eight patients (47 segments) who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage and an autologous cancellous iliac bone graft from June 2003 to August 2008 were enrolled in this study. The anterior and posterior segmental heights and the distance from the anterior edge of the upper vertebra to the anterior margin of the cage were measured on the plain radiographs. Subsidence was defined as ≥ a 2 mm (minor) or 3 mm (major) decrease of the segmental height at the final follow-up compared to that measured at the immediate postoperative period. Nonunion was evaluated according to the instability being ≥ 2 mm in the interspinous distance on the flexion-extension lateral radiographs. Results The anterior and posterior segmental heights decreased from the immediate postoperative period to the final follow-up at 1.33 ± 1.46 mm and 0.81 ± 1.27 mm, respectively. Subsidence ≥ 2 mm and 3 mm were observed in 12 segments (25.5%) and 7 segments (14.9%), respectively. Among the expected risk factors for subsidence, a smaller anteroposterior (AP) diameter (14 mm vs. 12 mm) of cages (p = 0.034; odds ratio [OR], 0.017) and larger intraoperative distraction (p = 0.041; OR, 3.988) had a significantly higher risk of subsidence. Intervertebral nonunion was observed in 7 segments (7/47, 14.9%). Compared with the union group, the nonunion group had a significantly higher ratio of two-level fusion to one-level fusions (p = 0.001). Conclusions Anterior cervical fusion using a stand-alone cage with a large AP diameter while preventing anterior intraoperative over-distraction will be helpful to prevent the subsidence of cages. Two-level cervical fusion might require more careful attention

  6. Radiologic Assessment of Subsidence in Stand-Alone Cervical Polyetheretherketone (PEEK) Cage

    PubMed Central

    Ha, Sung-Kon; Kim, Se-Hoon; Lim, Dong-Jun; Kim, Sang-Dae; Lee, Sang-Kook

    2008-01-01

    Objective Aim of study was to find a proper method for assessing subsidence using a radiologic measurement following anterior cervical discectomy and fusion (ACDF) with stand-alone polyetheretherketone (PEEK), Solis™ cage. Methods Forty-two patients who underwent ACDF with Solis™ cage were selected. With a minimum follow-up of 6 months, the retrospective investigation was conducted for 37 levels in 32 patients. Mean follow-up period was 18.9 months. Total intervertebral height (TIH) of two fused vertebral bodies was measured on digital radiographs with built-in software. Degree of subsidence (ΔTIH) was reflected by the difference between the immediate postoperative and follow-up TIH. Change of postoperative disc space height (CT-MRΔTIH) was reflected by the difference between TIH of the preoperative mid-sagittal 2D CT and that of the preoperative mid-sagittal T1-weighted MRI. Results Compared to preoperative findings, postoperative disc height was increased in all cases and subsidence was observed only in 3 cases. For comparison of subsidence and non-subsidence group, TIH and CT-MRΔTIH of each group were analyzed. There was no statistically significant difference in TIH and CT-MRΔTIH between each group at 4 and 8 weeks, but a difference was observed at the last follow-up TIH (p=0.0497). Conclusion ACDF with Solis™ cage was associated with relatively good radiologic long-term results. Fusion was achieved in 94.5% and subsidence occurred in 8.1% by the radiologic assessment. Statistical analysis reveals that the subsidence seen later than 8 weeks after surgery and the development of subsidence does not correlate statistically with the change of the postoperative disc space height. PMID:19137081

  7. Radiologic Assessment of Subsidence in Stand-Alone Cervical Polyetheretherketone (PEEK) Cage.

    PubMed

    Ha, Sung-Kon; Park, Jung-Yul; Kim, Se-Hoon; Lim, Dong-Jun; Kim, Sang-Dae; Lee, Sang-Kook

    2008-12-01

    Aim of study was to find a proper method for assessing subsidence using a radiologic measurement following anterior cervical discectomy and fusion (ACDF) with stand-alone polyetheretherketone (PEEK), Solistrade mark cage. Forty-two patients who underwent ACDF with Solistrade mark cage were selected. With a minimum follow-up of 6 months, the retrospective investigation was conducted for 37 levels in 32 patients. Mean follow-up period was 18.9 months. Total intervertebral height (TIH) of two fused vertebral bodies was measured on digital radiographs with built-in software. Degree of subsidence (DeltaTIH) was reflected by the difference between the immediate postoperative and follow-up TIH. Change of postoperative disc space height (CT-MRDeltaTIH) was reflected by the difference between TIH of the preoperative mid-sagittal 2D CT and that of the preoperative mid-sagittal T1-weighted MRI. Compared to preoperative findings, postoperative disc height was increased in all cases and subsidence was observed only in 3 cases. For comparison of subsidence and non-subsidence group, TIH and CT-MRDeltaTIH of each group were analyzed. There was no statistically significant difference in TIH and CT-MRDeltaTIH between each group at 4 and 8 weeks, but a difference was observed at the last follow-up TIH (p=0.0497). ACDF with Solistrade mark cage was associated with relatively good radiologic long-term results. Fusion was achieved in 94.5% and subsidence occurred in 8.1% by the radiologic assessment. Statistical analysis reveals that the subsidence seen later than 8 weeks after surgery and the development of subsidence does not correlate statistically with the change of the postoperative disc space height.

  8. Segmental kyphosis after cervical interbody fusion with stand-alone polyetheretherketone (PEEK) cages: a comparative study on 2 different PEEK cages.

    PubMed

    Kim, Chi Heon; Chung, Chun Kee; Jahng, Tae-Ahn; Park, Sung Bae; Sohn, Seil; Lee, Sungjoon

    2015-02-01

    Retrospective comparative study. Two polyetheretherketone (PEEK) cages of different designs were compared in terms of the postoperative segmental kyphosis after anterior cervical discectomy and fusion. Segmental kyphosis occasionally occurs after the use of a stand-alone cage for anterior cervical discectomy and fusion. Although PEEK material seems to have less risk of segmental kyphosis compared with other materials, the occurrence of segmental kyphosis for PEEK cages has been reported to be from 0% to 29%. There have been a few reports that addressed the issue of PEEK cage design. A total of 41 consecutive patients who underwent single-level anterior discectomy and fusion with a stand-alone cage were included. Either a round tube-type (Solis; 18 patients, S-group) or a trapezoidal tube-type (MC+; 23 patients, M-group) cage was used. The contact area between the cage and the vertebral body is larger in MC+ than in Solis, and anchoring pins were present in the Solis cage. The effect of the cage type on the segmental angle (SA) (lordosis vs. kyphosis) at postoperative month 24 was analyzed. Preoperatively, segmental lordosis was present in 12/18 S-group and 16/23 M-group patients (P=0.84). The SA was more lordotic than the preoperative angle in both groups just after surgery, with no difference between groups (P=0.39). At 24 months, segmental lordosis was observed in 9/18 S-group and 20/23 M-group patients (P=0.01). The patients in M-group were 7.83 times more likely than patients in S-group (P=0.04; odds ratio, 7.83; 95% confidence interval, 1.09-56.28) not to develop segmental kyphosis. The design of the PEEK cage used may influence the SA, and this association needs to be considered when using stand-alone PEEK cages.

  9. Comparison of allograft and polyetheretherketone (PEEK) cage subsidence rates in anterior cervical discectomy and fusion (ACDF).

    PubMed

    Yson, Sharon C; Sembrano, Jonathan N; Santos, Edward Rainier G

    2017-04-01

    Structural allografts and PEEK cages are commonly used interbody fusion devices in ACDF. The subsidence rates of these two spacers have not yet been directly compared. The primary aim of this study was to compare the subsidence rate of allograft and PEEK cage in ACDF. The secondary aim was to determine if the presence of subsidence affects the clinical outcome. We reviewed 67 cases (117 levels) of ACDF with either structural allograft or PEEK cages. There were 85 levels (48 cases) with PEEK and 32 levels (19 cases) with allograft spacers. Anterior and posterior disc heights at each operative level were measured at immediate and 6months post-op. Subsidence was defined as a decrease in anterior or posterior disc heights >2mm. NDI of the subsidence (SG) and non-subsidence group (NSG) were recorded. Chi-square test was used to analyze subsidence rates. T-test was used to analyze clinical outcomes (α=0.05). There was no statistically significant difference between subsidence rates of the PEEK (29%; 25/85) and allograft group (28%; 9/32) (p=0.69). Overall mean subsidence was 2.3±1.7mm anteriorly and 2.6±1.2mm posteriorly. Mean NDI improvement was 11.7 (from 47.1 to 35.4; average follow-up: 12mos) for the SG and 14.0 (from 45.8 to 31.8; average follow-up: 13mos) for the NSG (p=0.74). Subsidence rate does not seem to be affected by the use of either PEEK or allograft as spacers in ACDF. Furthermore, subsidence alone does not seem to be predictive of clinical outcomes of ACDF.

  10. Crystallization of Polyetheretherketone (PEEK) in Carbon Fiber Composites.

    DTIC Science & Technology

    1985-04-25

    AD-Ri56 316 CRYSTALLIZATION OF POLYETHERETHERKETONE (PEEK) IN 1/1 CARBON FIBER COMPOSITES (U) MASSACHUSETTS UNIY AMHERST MATERIALS RESEARCH LAB Y C...Crystallization of Polyetheretherketone (PEEK) in Carbon Fiber Composites by W C Y.C. Lee and Roger S. Porter Submitted for Publication I CO in Polymer...CRYSTALLIZATION OF POLYETHERETHERKETONE (PEEK) IN CARBON FIBER COMPOSITES By Y.C. Lee and Roger S. Porter Polymer Science and Engineering Department

  11. Empty polyetheretherketone (PEEK) cages in anterior cervical diskectomy and fusion (ACDF) show slow radiographic fusion that reduces clinical improvement: results from the prospective multicenter "PIERCE-PEEK" study.

    PubMed

    Suess, Olaf; Schomaker, Martin; Cabraja, Mario; Danne, Marco; Kombos, Theodoros; Hanna, Michael

    2017-01-01

    Anterior cervical diskectomy and fusion (ACDF) is a well-established surgical treatment for radiculopathy and myelopathy. Previous studies showed that empty PEEK cages have lower radiographic fusion rates, but the clinical relevance remains unclear. This paper's aim is to provide high-quality evidence on the outcomes of ACDF with empty PEEK cages and on the relevance of radiographic fusion for clinical outcomes. This large prospective multicenter clinical trial performed single-level ACDF with empty PEEK cages on patients with cervical radiculopathy or myelopathy. The main clinical outcomes were VAS (0-10) for pain and NDI (0-100) for functioning. Radiographic fusion was evaluated by two investigators for three different aspects. The median (range) improvement of the VAS pain score was: 3 (1-6) at 6 months, 3 (2-8) at 12 months, and 4 (2-8) at 18 months. The median (range) improvement of the NDI score was: 12 (2-34) at 6 months, 18 (4-46) at 12 months, and 22 (2-44) at 18 months. Complete radiographic fusion was reached by 126 patients (43%) at 6 months, 214 patients (73%) at 12 months, and 241 patients (83%) at 18 months. Radiographic fusion was a highly significant (p < 0.001) predictor of the improvement of VAS and NDI scores. This study provides strong evidence that ACDF is effective treatment, but the overall rate of radiographic fusion with empty PEEK cages is slow and insufficient. Lack of complete radiographic fusion leads to less improvement of pain and disability. We recommend against using empty uncoated pure PEEK cages in ACDF. ISRCTN42774128. Retrospectively registered 14 April 2009.

  12. Risk factors for subsidence in anterior cervical fusion with stand-alone polyetheretherketone (PEEK) cages: a review of 82 cases and 182 levels.

    PubMed

    Kao, Ting-Hsien; Wu, Chen-Hao; Chou, Yu-Ching; Chen, Hsien-Te; Chen, Wen-Hsien; Tsou, Hsi-Kai

    2014-10-01

    To determine risk factors for subsidence in patients treated with anterior cervical discectomy and fusion (ACDF) and stand-alone polyetheretherketone (PEEK) cages. Records of patients with degenerative spondylosis or traumatic disc herniation resulting in radiculopathy or myelopathy between C2 and C7 who underwent ACDF with stand-alone PEEK cages were retrospectively reviewed. Cages were filled with autogenous cancellous bone harvested from iliac crest or hydroxyapatite. Subsidence was defined as a decrease of 3 mm or more of anterior or posterior disc height from that measured on the postoperative radiograph. Eighty-two patients (32 males, 50 females; 182 treatment levels) were included in the analysis. Most patients had 1-2 treatment levels (62.2 %), and 37.8 % had 3-4 treatment levels. Treatment levels were from C2-7. Of the 82 patients, cage subsidence occurred in 31 patients, and at 39 treatment levels. Multivariable analysis showed that subsidence was more likely to occur in patients with more than two treatment levels, and more likely to occur at treatment levels C5-7 than at levels C2-5. Subsidence was not associated with postoperative alignment change but associated with more disc height change (relatively oversized cage). Subsidence is associated with a greater number of treatment levels, treatment at C5-7 and relatively oversized cage use.

  13. SESAME equation of state number 8020: Polyetheretherketone (PEEK)

    SciTech Connect

    Boettger, J.C.; Johnson, J.D.

    1993-12-01

    A new SESAME equation of state (EOS) for the polymer polyetheretherketone (PEEK) has been generated using the computer program GRIZZLY. This new EOS has been added to the SESAME EOS library as material number 8020. A few general guidelines for estimating the thermodynamic parameters for polymers needed to generate an EOS with GRIZZLY are suggested.

  14. Stand-alone cervical polyetheretherketone (PEEK) cage (cervios) for single to two-level degenerative disc disease.

    PubMed

    Iampreechakul, Prasert; Srisawat, Chaichan; Tirakotai, Wuttipong

    2011-02-01

    To study clinical and radiographic outcome of patients who underwent the Cervios cage-assisted anterior cervical discectomy and fusion (ACDF) without plate fixation in single to two-level degenerative disc disease (DDD). Sixty-seven patients suffering from cervical DDD with various symptoms such as radiculopathy, myelopathy, or both were retrospectively evaluated. The cervical DDD was confirmed by plain radiographs and MR imaging The patients underwent radiographic evaluation to assess cervical lordosis, intervertebral height (IH), fusion, and subsidence. Clinical assessment was graded using a visual analog scale (VAS), Modified JOA (Japanese Orthopedic Association) score, Neck Disability Index (NDI). There were ninety two ACFD in two levels of operation. Single-level ACDF was performed in 42 patients and two-level in 25. The outcomes revealed the significant improvement of clinical outcome and restoration of cervical lordosis. The fusion rate was 97%, whereas subsidence occurred 7.61% but produced no symptom. There was no anterior or posterior migration of the cage. Complications included transient dysphagia in three patients and superficial wound infection in two patients. The present study indicates that one- to two-level stand alone Cervios cage-assisted interbody fusion without plate fixation provides improvement of clinical outcomes, restoration of lordosis and high fusion rate. However subsidence occurred in 7.61% but did not cause clinical symptoms and the patients had to use the cervical collar postoperatively.

  15. Use of customized polyetheretherketone (PEEK) implants in the reconstruction of complex maxillofacial defects.

    PubMed

    Kim, Michael M; Boahene, Kofi D O; Byrne, Patrick J

    2009-01-01

    Extensive maxillofacial defects resulting from trauma or oncologic resection present reconstructive challenges. Various autografts and alloplastic materials in conjunction with standard soft-tissue techniques have been used in the reconstruction of these types of defects. Polyetheretherketone (PEEK) is a semicrystalline polyaromatic linear polymer exhibiting an excellent combination of strength, stiffness, durability, and environmental resistance. Recent investigations of PEEK as a biomaterial resulted in the successful treatment of cervical disk disease. We describe a series of 4 patients whose defects were reconstructed using customized PEEK implants. All had excellent postoperative aesthetic and functional results without complications such as infections or extrusions. Because PEEK implants are customizable, easily workable, inert, and nonporous, they represent an ideal alloplastic material for maxillofacial reconstruction.

  16. [Polyetheretherketone (PEEK). Part II: application in clinical practice].

    PubMed

    Pokorný, D; Fulín, P; Slouf, M; Jahoda, D; Landor, I; Sosna, A

    2010-01-01

    Polyetheretherketone (PEEK) is one of the up-to-date organic polymer thermoplastics with applications in orthopaedics and trauma medicine. This study presents a detailed analysis of its tests and applications in clinical medicine. A wide range of PEEK modifications and composites are commercially available, e.g., PEEK-Classix, PEEK-Optima, Endolign and Motis. They differ in their physical properties, which makes them suitable for different applications. Other forms, so-called PEEK bioactive composites, contain beta-tricalcium phosphate and hydroxyapatite. Research in this field is also concerned with the surface finish of this polymer thermoplastic and involves macroporous titanium and hydroxyapatite layers, or treatment with laser for an exactly defined surface structure. The clinical applications of PEEK and its composites include, in addition to components for spinal surgery, osteosynthesis plates, screws, intramedullary nails or external fixators, which are implants still at the stage of prototypes. In this review, attention is paid to the use of PEEK thermoplastics for joint replacement. Mid-term studies involving hundreds of patients have shown that, for instance, the VerSys Epoch Fullcoat Hip System (Zimmer) has a markedly lower stress-shielding effect. Carbon fibre-reinforced (CFR-PEEK) composites are used to make articulating components for total hip replacement. Their convenient properties allow for production of much thinner liners and an enlargement of the femoral head diameter, thus reducing the wear of joint implants. CFR-PEEK composites are particularly effective for hip resurfacing in which the Mitch PCR (Stryker) acetabular component has been used with good results. The MOTIS polymer acetabular cup (Invibio Ltd.) is another example. Further PEEK applications include the construction of finger-joint prostheses (Mathys AG), suture anchors (Stryker) and various kinds of augmentations (Medin). Based on the information obtained, the authors suggest

  17. A constitutive model of polyether-ether-ketone (PEEK).

    PubMed

    Chen, Fei; Ou, Hengan; Lu, Bin; Long, Hui

    2016-01-01

    A modified Johnson-Cook (JC) model was proposed to describe the flow behaviour of polyether-ether-ketone (PEEK) with the consideration of coupled effects of strain, strain rate and temperature. As compared to traditional JC model, the modified one has better ability to predict the flow behaviour at elevated temperature conditions. In particular, the yield stress was found to be inversely proportional to temperature from the predictions of the proposed model.

  18. Titanium vs. polyetheretherketone (PEEK) interbody fusion: Meta-analysis and review of the literature.

    PubMed

    Seaman, Scott; Kerezoudis, Panagiotis; Bydon, Mohamad; Torner, James C; Hitchon, Patrick W

    2017-10-01

    Spinal interbody fusion is a standard and accepted method for spinal fusion. Interbody fusion devices include titanium (Ti) and polyetheretherketone (PEEK) cages with distinct biomechanical properties. Titanium and PEEK cages have been evaluated in the cervical and lumbar spine, with conflicting results in bony fusion and subsidence. Using Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines, we reviewed the available literature evaluating Ti and PEEK cages to assess subsidence and fusion rates. Six studies were included in the analysis, 3 of which were class IV evidence, 2 were class III, and 1 was class II. A total of 410 patients (Ti-228, PEEK-182) and 587 levels (Ti-327, PEEK-260) were studied. Pooled mean age was 50.8years in the Ti group, and 53.1years in the PEEK group. Anterior cervical discectomy was performed in 4 studies (395 levels) and transforaminal interbody fusion in 2 studies (192 levels). No statistically significant difference was found between groups with fusion (OR 1.16, 95% C.I 0.59-2.89, p=0.686, I(2)=49.7%) but there was a statistically significant the rate of subsidence with titanium (OR 3.59, 95% C.I 1.28-10.07, p=0.015, I(2)=56.9%) at last follow-up. Titanium and PEEK cages are associated with a similar rate of fusion, but there is an increased rate of subsidence with titanium cage. Future prospective randomized controlled trials are needed to further evaluate these cages using surgical and patient-reported outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. In vivo experimental study of anterior cervical fusion using bioactive polyetheretherketone in a canine model.

    PubMed

    Shimizu, Takayoshi; Fujibayashi, Shunsuke; Yamaguchi, Seiji; Otsuki, Bungo; Okuzu, Yaichiro; Matsushita, Tomiharu; Kokubo, Tadashi; Matsuda, Shuichi

    2017-01-01

    Polyetheretherketone (PEEK) is a widely accepted biomaterial, especially in the field of spinal surgery. However, PEEK is not able to directly integrate with bone tissue, due to its bioinertness. To overcome this drawback, various studies have described surface coating approaches aimed at increasing the bioactivity of PEEK surfaces. Among those, it has been shown that the recently developed sol-gel TiO2 coating could provide PEEK with the ability to bond with bone tissue in vivo without the use of a bone graft. This in vivo experimental study using a canine model determined the efficacy of bioactive TiO2-coated PEEK for anterior cervical fusion. Sol-gel-derived TiO2 coating, which involves sandblasting and acid treatment, was used to give PEEK bone-bonding ability. The cervical interbody spacer, which was designed to fit the disc space of a beagle, was fabricated using bioactive TiO2-coated PEEK. Both uncoated PEEK (control) and TiO2-coated PEEK spacers were implanted into the cervical intervertebral space of beagles (n = 5 for each type). After the 3-month survival period, interbody fusion success was evaluated based on μ-CT imaging, histology, and manual palpation analyses. Manual palpation analyses indicated a 60% (3/5 cases) fusion (no gap between bone and implants) rate for the TiO2-coated PEEK group, indicating clear advantage over the 0% (0/5 cases) fusion rate for the uncoated PEEK group. The bony fusion rate of the TiO2-coated PEEK group was 40% according to μCT imaging; however, it was 0% of for the uncoated PEEK group. Additionally, the bone-implant contact ratio calculated using histomorphometry demonstrated a better contact ratio for the TiO2-coated PEEK group than for the uncoated PEEK group (mean, 32.6% vs 3.2%; p = 0.017). The TiO2-coated bioactive PEEK implant demonstrated better fusion rates and bone-bonding ability than did the uncoated PEEK implant in the canine anterior cervical fusion model. Bioactive PEEK, which has bone-bonding ability

  20. Investigation of the dynamic mechanical behavior of polyetheretherketone (PEEK) in the high stress tensile regime

    NASA Astrophysics Data System (ADS)

    Berer, M.; Major, Z.; Pinter, G.; Constantinescu, D. M.; Marsavina, L.

    2014-11-01

    Due to its outstanding mechanical performance both in static and dynamic loading and its resistance up to very high temperatures, Polyetheretherketone (PEEK) has attracted many practical applications. The loaded contact state for the application of PEEK rolls as bearing elements was recently analyzed by the corresponding author. High irreversible deformations on the mantle side were caused by the rolling contact and thus the rolling performance is supposed to be strongly affected by the dynamic mechanical properties of this irreversibly deformed material. Tensile fatigue tests at various stress levels up to the thermally dominated fatigue regime were conducted in order to get information regarding the dynamic mechanical material behavior at high stress regimes. Two types of PEEK (annealed and untreated) were investigated and two load ratios, R, were used (0.1 and 0.5). During the fatigue tests extensometer strain, load and surface temperature were recorded and a quantitative hysteresis loop analysis with calculated secant modulus and dynamic modulus was performed. Furthermore, the concept of isocyclic stress-strain diagrams was applied to enlarge and confirm the results obtained from the hysteresis loop analysis. A sharp transition between thermally dominated and mechanically dominated fatigue regimes was found for both PEEK types (annealed and untreated) and for both load ratios. Moreover, the annealed PEEK was stiffer in the tensile fatigue tests than the untreated material. Both examined PEEK types showed distinct hardening throughout the fatigue tests which made them "more elastic" (higher stiffness and less damping).

  1. The electron beam deposition of titanium on polyetheretherketone (PEEK) and the resulting enhanced biological properties.

    PubMed

    Han, Cheol-Min; Lee, Eun-Jung; Kim, Hyoun-Ee; Koh, Young-Hag; Kim, Keung N; Ha, Yoon; Kuh, Sung-Uk

    2010-05-01

    The surface of polyetheretherketone (PEEK) was coated with a pure titanium (Ti) layer using an electron beam (e-beam) deposition method in order to enhance its biocompatibility and adhesion to bone tissue. The e-beam deposition method was a low-temperature coating process that formed a dense, uniform and well crystallized Ti layer without deteriorating the characteristics of the PEEK implant. The Ti coating layer strongly adhered to the substrate and remarkably enhanced its wettability. The Ti-coated samples were evaluated in terms of their in vitro cellular behaviors and in vivo osteointegration, and the results were compared to a pure PEEK substrate. The level of proliferation of the cells (MC3T3-E1) was measured using a methoxyphenyl tetrazolium salt (MTS) assay and more than doubled after the Ti coating. The differentiation level of cells was measured using the alkaline phosphatase (ALP) assay and also doubled. Furthermore, the in vivo animal tests showed that the Ti-coated PEEK implants had a much higher bone-in-contact (BIC) ratio than the pure PEEK implants. These in vitro and in vivo results suggested that the e-beam deposited Ti coating significantly improved the potential of PEEK for hard tissue applications. Copyright 2009 Elsevier Ltd. All rights reserved.

  2. Anterior cervical discectomy and fusion: comparison of titanium and polyetheretherketone cages.

    PubMed

    Cabraja, Mario; Oezdemir, Soner; Koeppen, Daniel; Kroppenstedt, Stefan

    2012-09-14

    Titanium (TTN) cages have a higher modulus of elasticity when compared with polyetheretherketone (PEEK) cages. This suggests that TTN-cages could show more frequent cage subsidence after anterior cervical discectomy and fusion (ACDF) and therefore might lead to a higher loss of correction. We compared the long term results of stand-alone PEEK- and TTN-cages in a comparable patient collective that was operated under identical operative settings. From 2002 to 2007 154 patients underwent single-level ACDF for degenerative disc disease (DDD). Clinical and radiological outcome were assessed in 86 eligible patients after a mean of 28.4 months. 44 patients received a TTN- and 42 patients a PEEK-cage. Solid arthrodesis was found in 93.2% of the TTN-group and 88.1% of the PEEK-group. Cage subsidence was observed in 20.5% of the TTN- and 14.3% of the PEEK-group. A significant segmental lordotic correction was achieved by both cage-types. Even though a loss of correction was found at the last follow-up in both groups, it did not reach the level of statistical significance. Statistical analysis of these results revealed no differences between the TTN- and PEEK-group.When assessed with the neck disability index (NDI), the visual analogue scale (VAS) of neck and arm pain and Odom's criteria the clinical data showed no significant differences between the groups. Clinical and radiological outcomes of ACDF with TTN- or PEEK-cages do not appear to be influenced by the chosen synthetic graft. The modulus of elasticity represents only one of many physical properties of a cage. Design, shape, size, surface architecture of a cage as well as bone density, endplate preparation and applied distraction during surgery need to be considered as further important factors.

  3. Anterior cervical discectomy and fusion: Comparison of titanium and polyetheretherketone cages

    PubMed Central

    2012-01-01

    Background Titanium (TTN) cages have a higher modulus of elasticity when compared with polyetheretherketone (PEEK) cages. This suggests that TTN-cages could show more frequent cage subsidence after anterior cervical discectomy and fusion (ACDF) and therefore might lead to a higher loss of correction. We compared the long term results of stand-alone PEEK- and TTN-cages in a comparable patient collective that was operated under identical operative settings. Methods From 2002 to 2007 154 patients underwent single-level ACDF for degenerative disc disease (DDD). Clinical and radiological outcome were assessed in 86 eligible patients after a mean of 28.4 months. 44 patients received a TTN- and 42 patients a PEEK-cage. Results Solid arthrodesis was found in 93.2% of the TTN-group and 88.1% of the PEEK-group. Cage subsidence was observed in 20.5% of the TTN- and 14.3% of the PEEK-group. A significant segmental lordotic correction was achieved by both cage-types. Even though a loss of correction was found at the last follow-up in both groups, it did not reach the level of statistical significance. Statistical analysis of these results revealed no differences between the TTN- and PEEK-group. When assessed with the neck disability index (NDI), the visual analogue scale (VAS) of neck and arm pain and Odom’s criteria the clinical data showed no significant differences between the groups. Conclusions Clinical and radiological outcomes of ACDF with TTN- or PEEK-cages do not appear to be influenced by the chosen synthetic graft. The modulus of elasticity represents only one of many physical properties of a cage. Design, shape, size, surface architecture of a cage as well as bone density, endplate preparation and applied distraction during surgery need to be considered as further important factors. PMID:22978810

  4. Bonding of the Polymer Polyetheretherketone (PEEK) to Human Dentin: Effect of Surface Treatments.

    PubMed

    Rocha, Regina Furbino Villefort; Anami, Lilian Costa; Campos, Tiago Moreira Bastos; Melo, Renata Marques de; Souza, Rodrigo Othávio de Assunção E; Bottino, Marco Antonio

    2016-01-01

    Polyetheretherketone (PEEK) is a material suitable for frameworks of fixed dental prostheses. The effect of different surface treatments on the bond strength of PEEK bonded to human dentin was evaluated. One hundred PEEK cylinders (3 mm×3 mm) were divided into five groups according to surface treatment: silica coating, sandblasting with 45 μm Al2O3 particles, etching with 98% sulfuric acid for 5, 30 and for 60 s. These cylinders were luted with resin cement onto 50 human molars. First, each tooth was embedded in epoxy resin and the buccal dentin surface was exposed. Then, two delimited dentin areas (Æ:3 mm) per tooth were etched with 35% phosphoric acid and bonded with a two-step self-priming adhesive system. After the luting procedure the specimens were stored in water (24 h/37 °C). Shear bond strength (SBS) was tested using a universal testing machine (crosshead speed 0.5 mm/min; load cell 50 kgf) and failure types were assessed. Stress data (MPa) were analyzed using the Kruskal-Wallis test. Comparison of the proportions of different failure types was performed using the Bonferroni method (p<0.05). Kruskal-Wallis demonstrated that differences among groups were not significant (p=0.187). Mean SBS were as follows: silica coating, 2.12±1.12 MPa; sandblasting, 2.37±0.86 MPa; sulfuric acid 5 s, 2.28±1.75 MPa; sulfuric acid 30 s, 1.80±0.85 MPa; sulfuric acid 60 s, 1.67±0.94 MPa. Adhesive and mixed failures were predominant in all groups. Both physical and chemical surface treatments produced adhesion between PEEK, resin cement and dentin.

  5. Polyetheretherketone (PEEK) surface functionalization by low-energy ion-beam irradiation under a reactive O2 environment and its effect on the PEEK/copper adhesives.

    PubMed

    Kim, Sehyun; Lee, Ki-Jun; Seo, Yongsok

    2004-01-06

    A low-energy Ar+ ion beam was used to modify the surface of a polyetheretherketone (PEEK) film. The modification reaction proceeded with or without oxygen gas injected during the irradiation. The surface functional groups of the modified PEEK were confirmed with X-ray photoelectron spectroscopy as increasing various oxygen-containing functional groups. The concentration of the functional groups varied rapidly with the irradiation time, reached a maximum value, and then slowly decreased. The surface morphology of PEEK was substantially changed by ion-beam irradiation. Surface smoothening occurred so that the surface roughness reached almost constant value after some irradiation time. The incorporation of functional groups on the PEEK surface and the surface topology change had opposite effects on the adhesion strength between PEEK and copper. Dominance of the former was evident because the lap-shear strength initially increased with the irradiation. The special surface features significantly enhanced the adhesion strength between the evaporated copper layer and the modified PEEK surface. However, the decrease in the surface roughness with a long time irradiation implies a decrease in adhesion strength due to a smaller contact area, and the shear strength due to topology change also slowly decreased after a long time irradiation.

  6. In vitro and in vivo evaluation of bone morphogenetic protein-2 (BMP-2) immobilized collagen-coated polyetheretherketone (PEEK)

    NASA Astrophysics Data System (ADS)

    Du, Ya-Wei; Zhang, Li-Nan; Ye, Xin; Nie, He-Min; Hou, Zeng-Tao; Zeng, Teng-Hui; Yan, Guo-Ping; Shang, Peng

    2015-03-01

    Polyetheretherketone (PEEK) is regarded as one of the most potential candidates of biomaterials in spinal implant applications. However, as a bioinert material, PEEK plays a limited role in osteoconduction and osseointegration. In this study, recombinant human bone morphogenetic protein-2 (rhBMP-2) was immobilized onto the surface of collagen-coated PEEK in order to prepare a multi-functional material. After adsorbed onto the PEEK surface by hydrophobic interaction, collagen was cross-linked with N-(3-dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). EDC/NHS system also contributed to the immobilization of rhBMP-2. Water contact angle tests, XPS and SEM clearly demonstrated the surface changes. ELISA tests quantified the amount of rhBMP-2 immobilized and the release over a period of 30 d. In vitro evaluation proved that the osteogenesis differentiation rate was higher when cells were cultured on modified PEEK discs than on regular ones. In vivo tests were conducted and positive changes of major parameters were presented. This report demonstrates that the rhBMP-2 immobilized method for PEEK modification increase bioactivity in vitro and in vivo, suggesting its practicability in orthopedic and spinal clinical applications.

  7. Study on the Tribological Behaviors of Different PEEK Composite Coatings for Use as Artificial Cervical Disk Materials

    NASA Astrophysics Data System (ADS)

    Song, Jian; Liao, Zhenhua; Wang, Song; Liu, Yuhong; Liu, Weiqiang; Tyagi, Rajnesh

    2016-01-01

    Poly(ether-ether-ketone) (PEEK) is a type of biomaterial which may be used for modifying the surface of materials used in implants. Hence, in the present investigation, the potentiality of PEEK and its composites coatings has been explored for improving the friction and wear behavior of the Ti6Al4V to be used for cervical disks. The structural characteristics, micro-hardness, friction, and wear characteristics of PEEK/Al2O3 and PEEK/SiO2 composite coatings have been investigated and compared with pure PEEK coating and bare titanium alloy sample. According to the XRD analysis results, these coated samples were mainly orthorhombic crystalline form. The contact angle values of PEEK and its composite coatings were higher, while micro-hardness values of these samples decreased significantly. The thickness values of the three coated samples were all above 70 μm on average. The average friction coefficients with a counterface of ZrO2 ball decreased significantly, especially under NCS (newborn calf serum) lubricated condition. After comprehensive evaluation, the PEEK/Al2O3 coating demonstrated optimum tribological properties and could be applied as bearing materials for artificial cervical disk.

  8. Anterior cervical interbody fusion using polyetheretherketone cage filled with synthetic bone graft in acute cervical spine injury.

    PubMed

    Hattou, L; Morandi, X; Lefebvre, J; Le Reste, P-J; Riffaud, L; Hénaux, P-L

    2017-02-01

    The aim of this study was to assess the interbody fusion rate for patients treated by anterior cervical interbody fusion (ACIF) using polyetheretherketone (PEEK) cages filled with synthetic bone graft in acute cervical spine injury. Twenty-nine patients (mean age: 49 years) with monosegmental instability due to cervical spine injury were followed. We assessed the rate of and time to interbody fusion at 1-year follow-up. In case of secondary displacement, we analysed its causes and surgical management. The rate of fusion was 86.2%. The mean time to fusion was 7.2 months. Interbody fusion was observed at 3 months in 4 patients, at 6 months in 14 and at 1 year in 7. Four patients had secondary displacement within 3 months. ACIF with a PEEK cage filled with synthetic bone graft seems to be an alternative to iliac crest bone graft with no morbidity related to the harvest site. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Comparison of stand-alone polyetheretherketone cages and iliac crest autografts for the treatment of cervical degenerative disc diseases.

    PubMed

    Zhou, Jian; Xia, Qing; Dong, Jian; Li, Xilei; Zhou, Xiaogang; Fang, Taolin; Lin, Hong

    2011-01-01

    Anterior cervical decompression and fusion (ACDF) is a widely accepted surgical procedure for the treatment of cervical degenerative disc diseases. This retrospective study was designed to analyze and compare the efficacy and outcomes of anterior cervical fusion using stand-alone polyetheretherketone (PEEK) cages and autogenous iliac crest grafts with the anterior cervical plating system. A total of 72 consecutive patients suffering from cervical degenerative disc diseases treated with ACDF from June 2005 to Dec 2008 were enrolled in the study. Patients in group A (40 patients, 64 segments) had anterior interbody fusion with stand-alone PEEK cages and patients in group B (32 patients, 51 segments) with autogenous iliac crest graft combined with anterior plate fixation. The operative time and intraoperative blood loss were recorded. Clinical outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scoring system; cervical lordosis, intervertebral height, and cervical fusion status were assessed on X-ray and computed tomography. The mean follow-up period was 17.3 months in the stand-alone cage group and 23.2 months in the autologous iliac crest graft group. The operative time and intraoperative blood loss in group A were much less than those in group B (p < 0.05). All the patients in both groups got complete interbody fusion. Postoperative JOA scores in both group A and group B were more than the preoperative ones with significant differences, and the improvement rate of JOA scores had no statistical differences between group A and group B. Postoperative cervical physiological curvature and intervertebral height in both groups were better than the preoperative ones with statistical significances. The stand-alone PEEK cage is a good substitute for fusion in patients with cervical disc disease; it can effectively restore the cervical physiological curvature and the intervertebral height, facilitate radiological follow-up, cause few complications, and

  10. Comparative Study between a Curved and a Wedge PEEK Cage for Single-level Anterior Cervical Discectomy and Interbody Fusion.

    PubMed

    Kim, Hwan Soo; Song, Joon Suk; Heo, Weon; Cha, Jae Hoon; Rhee, Dong Youl

    2012-09-01

    This study evaluated the efficiency of a curved polyetheretherketone (PEEK) cage in comparison with a wedge PEEK cage according to radiologic and clinical outcomes in patients with cervical degenerative disease. A total of 37 patients who suffering from cervical disc disease with radiculopathy or myelopathy were reviewed retrospectively. Seventeen patients were underwent anterior cervical discectomy and interbody fusion with a curved shape PEEK cage (curved cage group), and twenty patients with wedge shape PEEK cage (wedge cage group). Clinical assessment was graded using Odom's criteria, NDI score and VAS score. For radiologic analysis, disc height (DH), segmental angle (SA), subsidence were measured at the preoperative and last follow up. A comparison of the preoperative and postoperative results revealed improvements after the surgery in the DH and SA in both cage groups. The change of postoperative DH between the preoperative and the last follow-up in wedge cage group and curved cage group was 6.85% and 25.5%, respectively. The change of postoperative SA was 1.75° and 0.95°, respectively. There was no statistically significant difference in the DH and SA between the 2 groups. The subsidence rate in the wedge cage group and curved cage group was 20% and 6%, respectively. The 2 different cage groups showed significant improvements in the disc height, segmental angle and clinical outcomes. However, the shape of PEEK Cage influences the tendency for subsidence. Increasing contact surface area and fitting into two adjacent vertebral body prevent significant subsidence.

  11. Clinical and biomechanical researches of polyetheretherketone (PEEK) rods for semi-rigid lumbar fusion: a systematic review.

    PubMed

    Li, Chan; Liu, Lei; Shi, Jian-Yong; Yan, Kai-Zhong; Shen, Wei-Zhong; Yang, Zhen-Rong

    2016-07-08

    Lumbar spinal fusion using rigid rods is a common surgical technique. However, adjacent segment disease and other adverse effects can occur. Dynamic stabilization devices preserve physiologic motion and reduce painful stress but have a high rate of construct failure and reoperation. Polyetheretherketone (PEEK) rods for semi-rigid fusions have a similar stiffness and adequate stabilization power compared with titanium rods, but with improved load sharing and reduced mechanical failure. The purpose of this paper is to review and evaluate the clinical and biomechanical performance of PEEK rods. A systematic review of clinical and biomechanical studies was conducted. A literature search using the PubMed, EMBASE, and Cochrane Library databases identified studies that met the eligibility criteria. Eight clinical studies and 15 biomechanical studies were included in this systematic review. The visual analog scale and the Oswestry disability index improved significantly in most studies, with satisfactory fusion rates. The occurrence of adjacent segment disease was low. In biomechanical studies, PEEK rods demonstrated a superior load-sharing distribution, a larger adjacent segment range of motion, and reduced stress at the rod-screw/screw-bone interfaces compared with titanium rods. The PEEK rod construct was simple to assemble and had a reliable in vivo performance compared with dynamic devices. The quality of clinical studies was low with confounding results, although results from mechanical studies were encouraging. There is no evidence strong enough to confirm better outcomes with PEEK rods than titanium rods. More studies with better protocols, a larger sample size, and a longer follow-up time are needed.

  12. Polyetheretherketone Cage with Demineralized Bone Matrix Can Replace Iliac Crest Autografts for Anterior Cervical Discectomy and Fusion in Subaxial Cervical Spine Injuries

    PubMed Central

    Kim, Soo-Han; Lee, Jung-Kil; Jang, Jae-Won; Park, Hyun-Woong; Hur, Hyuk

    2017-01-01

    Objective This study aimed to compare the clinical and radiologic outcomes of patients with subaxial cervical injury who underwent anterior cervical discectomy and fusion (ACDF) with autologous iliac bone graft or polyetheretherketone (PEEK) cages using demineralized bone matrix (DBM). Methods From January 2005 to December 2010, 70 patients who underwent one-level ACDF with plate fixation for post-traumatic subaxial cervical spinal injury in a single institution were retrospectively investigated. Autologous iliac crest grafts were used in 33 patients (Group I), whereas 37 patients underwent ACDF using a PEEK cage filled with DBM (Group II). Plain radiographs were used to assess bone fusion, interbody height (IBH), segmental angle (SA), overall cervical sagittal alignment (CSA, C2–7 angle), and development of adjacent segmental degeneration (ASD). Clinical outcome was assessed using a visual analog scale (VAS) for pain and Frankel grade. Results The mean follow-up duration for patients in Group I and Group II was 28.9 and 25.4 months, respectively. All patients from both groups achieved solid fusion during the follow-up period. The IBH and SA of the fused segment and CSA in Group II were better maintained during the follow-up period. Nine patients in Group I and two patients in Group II developed radiologic ASD. There were no statistically significant differences in the VAS score and Frankel grade between the groups. Conclusion This study showed that PEEK cage filled with DBM, and plate fixation is at least as safe and effective as ACDF using autograft, with good maintenance of cervical alignment. With advantages such as no donor site morbidity and no graft-related complications, PEEK cage filled with DBM, and plate fixation provide a promising surgical option for treating traumatic subaxial cervical spine injuries. PMID:28264242

  13. Polyetheretherketone Cage with Demineralized Bone Matrix Can Replace Iliac Crest Autografts for Anterior Cervical Discectomy and Fusion in Subaxial Cervical Spine Injuries.

    PubMed

    Kim, Soo-Han; Lee, Jung-Kil; Jang, Jae-Won; Park, Hyun-Woong; Hur, Hyuk

    2017-03-01

    This study aimed to compare the clinical and radiologic outcomes of patients with subaxial cervical injury who underwent anterior cervical discectomy and fusion (ACDF) with autologous iliac bone graft or polyetheretherketone (PEEK) cages using demineralized bone matrix (DBM). From January 2005 to December 2010, 70 patients who underwent one-level ACDF with plate fixation for post-traumatic subaxial cervical spinal injury in a single institution were retrospectively investigated. Autologous iliac crest grafts were used in 33 patients (Group I), whereas 37 patients underwent ACDF using a PEEK cage filled with DBM (Group II). Plain radiographs were used to assess bone fusion, interbody height (IBH), segmental angle (SA), overall cervical sagittal alignment (CSA, C2-7 angle), and development of adjacent segmental degeneration (ASD). Clinical outcome was assessed using a visual analog scale (VAS) for pain and Frankel grade. The mean follow-up duration for patients in Group I and Group II was 28.9 and 25.4 months, respectively. All patients from both groups achieved solid fusion during the follow-up period. The IBH and SA of the fused segment and CSA in Group II were better maintained during the follow-up period. Nine patients in Group I and two patients in Group II developed radiologic ASD. There were no statistically significant differences in the VAS score and Frankel grade between the groups. This study showed that PEEK cage filled with DBM, and plate fixation is at least as safe and effective as ACDF using autograft, with good maintenance of cervical alignment. With advantages such as no donor site morbidity and no graft-related complications, PEEK cage filled with DBM, and plate fixation provide a promising surgical option for treating traumatic subaxial cervical spine injuries.

  14. Comparison between Two Different Cervical Interbody Fusion Cages in One Level Stand-alone ACDF: Carbon Fiber Composite Frame Cage Versus Polyetheretherketone Cage

    PubMed Central

    Yoo, Minwook; Kim, Wook-Ha; Hyun, Seung-Jae; Jahng, Tae-Ahn; Kim, Hyun-Jib

    2014-01-01

    Objective The authors conducted a retrospective study to compare the implantation of carbon fiber composite frame cages (CFCFCs) to the implantation of polyetheretherketone (PEEK) cages after anterior cervical discectomy for cervical degenerative disc disease. In addition, the predictive factors that influenced fusion or subsidence were investigated. Methods A total of 58 patients with single-level degenerative disc disease were treated with anterior cervical discectomy and implantation of stand-alone cages; CFCFCs were used in 35 patients, and PEEK cages were used in 23 patients. Preoperative and postoperative radiological and clinical assessments were performed. Results During the mean follow-up period of 41 months, fusion occurred in 43 patients (74.1%), and subsidence developed in 18 patients (31.0%). Pain decreased in all patients, and the patients' satisfaction rate was 75.9%. Neither fusion nor subsidence was related to the clinical outcome. There were no significant differences in the clinical and radiological outcomes between the CFCFC and the PEEK cage groups. Smoking history (p=0.023) was significantly associated with pseudarthrosis, and cage height (≥7mm) (p=0.037) were significantly associated with subsidence. Conclusion The clinical and radiological results were similar between the CFCFC and the PEEK cage groups. Fusion or subsidence did not affect the clinical outcomes. Smoking history and cage height (≥7mm) were predictive factors for pseudarthrosis or subsidence in anterior cervical discectomy and fusion with stand-alone cages. PMID:25346758

  15. Comparison between Two Different Cervical Interbody Fusion Cages in One Level Stand-alone ACDF: Carbon Fiber Composite Frame Cage Versus Polyetheretherketone Cage.

    PubMed

    Yoo, Minwook; Kim, Wook-Ha; Hyun, Seung-Jae; Kim, Ki-Jeong; Jahng, Tae-Ahn; Kim, Hyun-Jib

    2014-09-01

    The authors conducted a retrospective study to compare the implantation of carbon fiber composite frame cages (CFCFCs) to the implantation of polyetheretherketone (PEEK) cages after anterior cervical discectomy for cervical degenerative disc disease. In addition, the predictive factors that influenced fusion or subsidence were investigated. A total of 58 patients with single-level degenerative disc disease were treated with anterior cervical discectomy and implantation of stand-alone cages; CFCFCs were used in 35 patients, and PEEK cages were used in 23 patients. Preoperative and postoperative radiological and clinical assessments were performed. During the mean follow-up period of 41 months, fusion occurred in 43 patients (74.1%), and subsidence developed in 18 patients (31.0%). Pain decreased in all patients, and the patients' satisfaction rate was 75.9%. Neither fusion nor subsidence was related to the clinical outcome. There were no significant differences in the clinical and radiological outcomes between the CFCFC and the PEEK cage groups. Smoking history (p=0.023) was significantly associated with pseudarthrosis, and cage height (≥7mm) (p=0.037) were significantly associated with subsidence. The clinical and radiological results were similar between the CFCFC and the PEEK cage groups. Fusion or subsidence did not affect the clinical outcomes. Smoking history and cage height (≥7mm) were predictive factors for pseudarthrosis or subsidence in anterior cervical discectomy and fusion with stand-alone cages.

  16. Four-corner arthrodesis with a locking, dorsal circular polyether-ether-ketone (PEEK-Optima) plate.

    PubMed

    Rhee, Peter C; Kakar, Sanjeev; Shin, Alexander Y

    2012-12-01

    Scaphoidectomy and 4-corner arthrodesis can be a successful salvage procedure for scaphoid nonunion advanced collapse and scapholunate advanced collapse. Traditional methods of fixation include Kirschner wires, staples, and/or headless compression screws. Nonlocking, dorsal circular plates, manufactured from stainless steel, have been advocated to allow early wrist range of motion and improved union rates. However, the reported union rates have been variable and inconsistent. This wide results have been attributed to the difficulty in assessing union with plain film radiograph due to the radio-opaque plate. Recently, a locking, dorsal circular plate, comprised of a radiolucent polyether-ether-ketone (PEEK-Optima), has been introduced with the additional benefit of providing a fixed-angle construct and allowing a more accurate assessment of bone union with plain film imaging studies.

  17. Spectrophotometric Evaluation of Polyetheretherketone (PEEK) as a Core Material and a Comparison with Gold Standard Core Materials.

    PubMed

    Stawarczyk, Bogna; Schmid, Philipp; Roos, Malgorzata; Eichberger, Marlis; Schmidlin, Patrick R

    2016-06-20

    This study investigated the colorimetric properties of different veneering materials on core materials. Standardized specimens (10 mm × 10 mm × 1.5 mm) reflecting four core (polyetheretherketone (PEEK), zirconia (ZrO₂), cobalt-chromium-molybdenum alloy (CoCrMo), and titanium oxide (TiO₂); thickness: 1.5 mm) and veneering materials (VITA Mark II, IPS e.max CAD, LAVA Ultimate and VITA Enamic, all in shade A3; thickness: 0.5, 1.0, 1.5 and 2 mm, respectively) were fabricated. Specimens were superimposed to assemblies, and the color was determined with a spectrophotometer (CieLab-System) or a chair-side color measurement device (VITA EasyShade), respectively. Data were analyzed using three-, two-, and one-way ANOVA, a Chi²-test, and a Wilson approach (p < 0.05). The measurements with EasyShade showed A2 for VITA Mark II, A3.5 for VITA Enamic, B2 for LAVA Ultimate, and B3 for IPS e.max CAD. LabE-values showed significant differences between the tested veneering materials (p < 0.001). CieLab-System and VITA EasyShade parameters of the different assemblies showed a significant impact of core (p < 0.001), veneering material (p < 0.001), and thickness of the veneering material (p < 0.001). PEEK as core material showed comparable outcomes as compared to ZrO₂ and CoCrMo, with respect to CieLab-System parameters for each veneering material. The relative frequency of the measured VITA EasyShade parameters regarding PEEK cores also showed comparable results as compared to the gold standard CoCrMo, regardless of the veneering material used.

  18. [Complex skull defects reconstruction with САD/САМ titanium and polyetheretherketone (PEEK) implants].

    PubMed

    Eolchiyan, S A

    2014-01-01

    Predictable and stable functional and aesthetic result is the aim of priority for the neurosurgeon dealing with the reconstruction of large cranial bone defects and complex-formed skull defects involving cranio-orbital region. the paper presents the experience with САD/САМ titanium and polyetheretherketone (PEEK) implants for complex-formed and large skull bone defects reconstruction. Between 2005 and 2013 nine patients (5 females and 4 males) underwent cranioplasty and cranio-facial reconstruction with insertion of the customized САD/САМ titanium and PEEK implants. Computer-assisted preoperative planning was undertaken by the surgeon and the engineer together in 3 cases to provide accurate implant design. Eight patients had complex-formed and large posttraumatic defects of fronto-orbital (7 cases) and parietal (one case) regions. In two of these cases one-step reconstruction surgery for posttraumatic fronto-orbital defects combined with adjacent orbital roof (one case) and orbito-zygomatic (one case) deformities was performed. One patient underwent one-step primary cranioplasty after cranio-orbital fibrous dysplasia focus resection. Titanium implants were used in 4 cases while PEEK implants - in 5 ones. The follow-up period ranged from 6 months till 8,5 years (median 4,4 years). The accuracy of the implant intraoperative fit was perfect in all cases. Postoperative wounds healed primary and there were no any complications in the series presented. Post-op clinical assessment and CT data testified to high implants precision, good functional and aesthetic outcomes in all patients. САD/САМ titanium and PEEK implants application should allow for optimal reconstruction in the challenging patients with complex-formed and large skull bone defects providing predictable good functional and aesthetic result together with surgery morbidity and duration reduction. Computer-assisted preoperative planning should be undertaken for САD/САМ implants creation in

  19. Comparative Study between a Curved and a Wedge PEEK Cage for Single-level Anterior Cervical Discectomy and Interbody Fusion

    PubMed Central

    Kim, Hwan Soo; Heo, Weon; Cha, Jae Hoon; Rhee, Dong Youl

    2012-01-01

    Objective This study evaluated the efficiency of a curved polyetheretherketone (PEEK) cage in comparison with a wedge PEEK cage according to radiologic and clinical outcomes in patients with cervical degenerative disease. Methods A total of 37 patients who suffering from cervical disc disease with radiculopathy or myelopathy were reviewed retrospectively. Seventeen patients were underwent anterior cervical discectomy and interbody fusion with a curved shape PEEK cage (curved cage group), and twenty patients with wedge shape PEEK cage (wedge cage group). Clinical assessment was graded using Odom's criteria, NDI score and VAS score. For radiologic analysis, disc height (DH), segmental angle (SA), subsidence were measured at the preoperative and last follow up. Results A comparison of the preoperative and postoperative results revealed improvements after the surgery in the DH and SA in both cage groups. The change of postoperative DH between the preoperative and the last follow-up in wedge cage group and curved cage group was 6.85% and 25.5%, respectively. The change of postoperative SA was 1.75° and 0.95°, respectively. There was no statistically significant difference in the DH and SA between the 2 groups. The subsidence rate in the wedge cage group and curved cage group was 20% and 6%, respectively. Conclusion The 2 different cage groups showed significant improvements in the disc height, segmental angle and clinical outcomes. However, the shape of PEEK Cage influences the tendency for subsidence. Increasing contact surface area and fitting into two adjacent vertebral body prevent significant subsidence. PMID:25983812

  20. [Use of the PEEK cage in cervical spondylosis treatment].

    PubMed

    Joachin-Hernández, Pedro; Alpízar-Aguirre, Armando; Zárate-Kalfópulus, Barón; Rosales-Olivares, Luis Miguel; Sánchez-Bringas, Guadalupe; Reyes-Sánchez, Alejandro Antonio

    2013-01-01

    Decompression and fusion with autograft is the gold standard technique in the treatment of cervical canal strait. Using PEEK cages or boxes of non-absorbable polymer with elasticity similar to bone, radiolucent, reduces morbidity and same degree of fusion. A case series, prospective, longitudinal, deliberate intervention, evaluation panel before and after 2 years follow-up. Discectomy and PEEK housing placement with autologous graft. Arthrodesis were evaluated, cervical lordosis, intervertebral space height, pain evaluated with Visual Analogue Scale, Neck Disability Index, operative time, intraoperative bleeding, hospital stay and complications. Statistical analysis with t Sudent, Wilcoxon and Fisher's exact text. Of 17 patients studied, 9 (53%) were female. Average age 62 years. The most affected level was C5-6, C6-7 with 5 patients. Melting was found at 100%. There was no sag or migration of the box, space height was conserved, but segmental lordosis was not retained. Clinical improvement in all patients as well as disability index was seen. Bleeding was on average 187 mL. With regard to symptom improvement, conservation of interspace height and back, no segmental lordosis conservation and fusion using PEEK box is consistent with the literature. We suggest using anterior plate to maintain cervical lordosis. We found a melt index of 100%. We found clinical improvement of symptoms, pain and disability, and a global loss of cervical lordosis.

  1. Anterior cervical discectomy and fusion using a stand-alone polyetheretherketone cage packed with local autobone : assessment of bone fusion and subsidence.

    PubMed

    Park, Jeong-Ill; Cho, Dae-Chul; Kim, Kyoung-Tae; Sung, Joo-Kyung

    2013-09-01

    It remains debatable whether cervical spine fusion cages should be filled with any kind of bone or bone substitute. Cortical and subcortical bone from the anterior and posterior osteophytes of the segment could be used to fill the cage. The purposes of the present study are to evaluate the clinical outcomes and radiological outcomes including bone fusion and subsidence that occurred after anterior cervical discectomy and fusion using a stand-alone cage packed with local autobone graft. Thirty-one patients who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage packed with local autobone graft from July 2009 to december 2011 were enrolled in this study. Bone fusion was assessed by cervical plain radiographs and computed tomographic scan. Nonunion was evaluated according to the absence of bony bridge on computed tomographic scan. Subsidence was defined as a ≥2 mm decrease of the interbody height at the final follow-up compared to that measured at the immediate postoperative period. Subsidence was observed in 7 patients (22.6%). Of 7 patients with subsidence greater 2 mm, nonunion was developed in 3. Three patients with subsidence greater 2 mm were related with endplate damage during intraoperative endplate preparation. Solid bone fusion was achieved in 28 out of 31 patients (90.3%). With proper patient selection and careful endplate preparation, anterior cervical discectomy and fusion (ACDF) using a stand-alone PEEK cage packed with local autobone graft could be a good alternative to the standard ACDF techniques with plating.

  2. The influence of nominal stress on wear factors of carbon fibre-reinforced polyetheretherketone (PEEK-OPTIMA® Wear Performance) against zirconia toughened alumina (Biolox® delta ceramic).

    PubMed

    Evans, Andrew; Horton, Henrietta; Unsworth, Anthony; Briscoe, Adam

    2014-06-01

    Carbon fibre-reinforced polyetheretherketone is an attractive alternative to ultra-high-molecular-weight polyethylene in artificial joints, but little has been published on the influence of stress on the wear factor. We know that in ultra-high-molecular-weight polyethylene, the wear factor reduces as the normal stress increases, which is counter-intuitive but very helpful in the case of non-conforming contacts. In this study, carbon fibre-reinforced polyetheretherketone (PEEK-OPTIMA(®) Wear Performance) has been investigated in a pin-on-plate machine under steady loads and under stresses typical of hip and knee joints. At stresses below about 6 MPa, wear factors are between 10 and a 100 times lower than for ultra-high-molecular-weight polyethylene but at higher stresses the wear factors increase substantially.

  3. The Use of a Modified Poly-Ether-Ether-Ketone (PEEK) as an Alternative Framework Material for Removable Dental Prostheses. A Clinical Report.

    PubMed

    Zoidis, Panagiotis; Papathanasiou, Ioannis; Polyzois, Gregory

    2016-10-01

    This clinical report presents a modified poly-ether-ether-ketone (PEEK) as an alternative material for the fabrication of distal extension removable dental prosthesis (RDP) frameworks. This material can be used for patients allergic to metals, or who dislike the metallic taste, the weight, and the unpleasant metal display of the denture framework and retentive clasps. This modified PEEK material, known as BioHPP, is a biocompatible, nonallergic, rigid material, with flexibility comparable to bone, high polishing and low absorption properties, low plaque affinity, and good wear resistance. It has been used for years in orthopedics and medical technology. BioHPP frameworks can be constructed either via CAD/CAM manufacturing or via the conventional lost wax technique. The clinical use of a BioHPP RDP framework is presented as an alternative for the treatment of a distal extension case.

  4. Mechanical characterization and numerical simulation of polyether-ether-ketone (PEEK) cranial implants.

    PubMed

    El Halabi, F; Rodriguez, J F; Rebolledo, L; Hurtós, E; Doblaré, M

    2011-11-01

    Cranial implants have experienced a significant evolution in the last decade in different aspects such as materials, method of fixation, and the structure. In addition, patient-specific cranial implants have recently been started to be developed. To achieve this objective, efficient mechanical characterization and numerical modeling of the implant are required to guarantee its functionality on each patient as well as to facilitate further developments. In this work, mechanical characterization and numerical models have been performed for patient-specific Polyaryletherketone (PEEK) scaffold cranial implants. Mechanical characterization has been performed at the scaffold and the whole implant levels under displacement control tests. Two different implant designs for the same patient but with different scaffold structure were experimentally characterized, and finite element models of the implants were developed within the framework of linear elasticity. Two types of finite element models were developed: a detailed finite element model with the actual scaffold geometry, and a solid shell-like model with effective material properties. These effective material properties were obtained by means of the Asymptotic Expansion Homogenization (AEH) theory which accounts for the periodicity of the underlying structure of the material. Experimental results showed a linear response of the material and the implant up to failure, therefore supporting the use of linear elastic models for simulation. Numerical models showed excellent agreement with experiments regarding load-displacement response. Models also showed a very consistent behavior with regard to the location and the value of the maximum principal stress in the implant when subjected to the maximum load of the experiments. The two numerical models were compared. The homogenized model gave results that were very close to those obtained with the detailed model, while reducing the number of degrees of freedom by 90%, and

  5. Wear studies on ZrO2-filled PEEK as coating bearing materials for artificial cervical discs of Ti6Al4V.

    PubMed

    Song, Jian; Liu, Yuhong; Liao, Zhenhua; Wang, Song; Tyagi, Rajnesh; Liu, Weiqiang

    2016-12-01

    Polyetheretherketone (PEEK) and its composite coatings are believed to be the potential candidates' bio-implant materials. However, these coatings have not yet been used on the surface of titanium-based orthopedics and joint products and very few investigations on the tribological characteristics could be found in the published literature till date. In this study, the wettabilities, composition and micro-hardness were characterized using contact angle measurement, scanning electron microscopy (SEM) and hardness tester. The tribological tests were conducted using a ball-on-disc contact pair under 25% newborn calf serum (NCS) lubricated condition. For comparison, bare Ti6Al4V was studied. The obtained results revealed that those PEEK/ZrO2 composite coatings could improve the tribological properties of Ti6Al4V significantly. Adhesive wear and mild abrasive wear might be the dominant wear and failure mechanisms for PEEK/ZrO2 composite coatings in NCS lubricated condition. After comprehensive evaluation in the present study, 5wt.% ZrO2 nanoparticles filled PEEK coating displayed the optimum tribological characteristics and could be taken as a potential candidate for the bearing material of artificial cervical disc.

  6. Anterior Cervical Discectomy and Fusion Using a Stand-Alone Polyetheretherketone Cage Packed with Local Autobone : Assessment of Bone Fusion and Subsidence

    PubMed Central

    Park, Jeong-Ill; Kim, Kyoung-Tae; Sung, Joo-Kyung

    2013-01-01

    Objective It remains debatable whether cervical spine fusion cages should be filled with any kind of bone or bone substitute. Cortical and subcortical bone from the anterior and posterior osteophytes of the segment could be used to fill the cage. The purposes of the present study are to evaluate the clinical outcomes and radiological outcomes including bone fusion and subsidence that occurred after anterior cervical discectomy and fusion using a stand-alone cage packed with local autobone graft. Methods Thirty-one patients who underwent anterior cervical fusion using a stand-alone polyetheretherketone (PEEK) cage packed with local autobone graft from July 2009 to december 2011 were enrolled in this study. Bone fusion was assessed by cervical plain radiographs and computed tomographic scan. Nonunion was evaluated according to the absence of bony bridge on computed tomographic scan. Subsidence was defined as a ≥2 mm decrease of the interbody height at the final follow-up compared to that measured at the immediate postoperative period. Results Subsidence was observed in 7 patients (22.6%). Of 7 patients with subsidence greater 2 mm, nonunion was developed in 3. Three patients with subsidence greater 2 mm were related with endplate damage during intraoperative endplate preparation. Solid bone fusion was achieved in 28 out of 31 patients (90.3%). Conclusion With proper patient selection and careful endplate preparation, anterior cervical discectomy and fusion (ACDF) using a stand-alone PEEK cage packed with local autobone graft could be a good alternative to the standard ACDF techniques with plating. PMID:24278646

  7. SU-E-J-38: Improved DRR Image Quality Using Polyetheretherketone (PEEK) Fiducial in Image Guided Radiotherapy (IGRT)

    SciTech Connect

    Shen, S; Jacob, R; Popple, R; Duan, J; Wu, X; Cardan, R; Brezovich, I

    2015-06-15

    Purpose Fiducial-based imaging is often used in IGRT. Traditional gold fiducial marker often has substantial reconstruction artifacts. These artifacts Result in poor image quality of DRR for online kV-to-DRR matching. This study evaluated the image quality of PEEK in DRR in static and moving phantom. Methods CT scan of the Gold and PEEK fiducial (both 1×3 mm) was acquired in a 22 cm cylindrical phantom filled with water. Image artifacts was evaluated with maximum CT value deviated from water due to artifacts; volume of artifacts in 10×10 cm in the center slice; maximum length of streak artifacts from the fiducial. DRR resolution were measured using FWHM and FWTM. 4DCT of PEEK fiducial was acquired with the phantom moving sinusoidally in superior-inferior direction. Motion artifacts were assessed for various 4D phase angles. Results The maximum CT value deviation was −174 for Gold and −24 for PEEK. The volume of artifacts in a 10x10 cm 3 mm slice was 0.369 for Gold and 0.074 cm3 for PEEK. The maximum length of streak artifact was 80mm for Gold and 7 mm for PEEK. PEEK in DRR, FWHM was close to actual (1.0 mm for Gold and 1.1 mm for PEEK). FWTM was 1.8 mm for Gold and 1.3 mm for PEEK in DRR. Barrel motion artifact of PEEK fiducial was noticeable for free-breathing scan. The apparent PEEK length due to residual motion was in close agreement with the calculated length (13 mm for 30–70 phase, 10 mm in 40–60 phase). Conclusion Streak artifacts on planning CT associated with use of gold fiducial can be significantly reduced by PEEK fiducial, while having adequate kV image contrast. DRR image resolution at FWTM was improved from 1.8 mm to 1.3 mm. Because of this improvement, we have been routinely use PEEK for liver IGRT.

  8. Adhesion bonding techniques for highly loaded parts of continuous carbon-fiber reinforced polyetheretherketone (CF-PEEK/APC2)

    NASA Astrophysics Data System (ADS)

    Kempe, G.; Krauss, H.

    It is shown that the adhesion technology is applicable to the bonding of continuous fiber reinforced thermplastics. The influences and conditions under which an enhancement of the bonding strength can be achieved are described. Attention is focused on the applicability of the adhesion method to continuous fiber reinforced PEEK, acknowledging that PEEK is very resistant to chemicals and thereby, a poor candidate for the technique.

  9. Isothermal physical aging characterization of Polyether-ether-ketone (PEEK) and Polyphenylene sulfide (PPS) films by creep and stress relaxation

    NASA Astrophysics Data System (ADS)

    Guo, Yunlong; Bradshaw, Roger D.

    2007-03-01

    This paper considers the experimental characterization of isothermal physical aging of PEEK and PPS films using a dynamic mechanical analyzer. Using the short-term test method established by Struik, momentary creep and stress relaxation curves were measured at several temperatures within 15-35°C below the glass transition temperature ( T g ) at various aging times. Stress and strain levels were such that the materials remained in the linear viscoelastic regime. These curves were then shifted together to determine momentary master curves and shift rates using the PHYAGE program. In order to validate the obtained isothermal physical aging behavior, the results of creep and stress relaxation testing were compared and shown to be consistent with one another using appropriate interconversion of the viscoelastic material functions. Time-temperature superposition of the master curves was also performed. The temperature shift factors and aging shift rates for both PEEK and PPS were consistent for both creep and stress relaxation test results.

  10. Porous silicon nitride spacers versus PEEK cages for anterior cervical discectomy and fusion: clinical and radiological results of a single-blinded randomized controlled trial.

    PubMed

    Arts, Mark P; Wolfs, Jasper F C; Corbin, Terry P

    2017-04-05

    Anterior cervical discectomy with fusion is a common procedure for treating radicular arm pain. Polyetheretherketone (PEEK) plastic is a frequently used material in cages for interbody fusion. Silicon nitride is a new alternative with desirable bone compatibility and imaging characteristics. The aim of the present study is to compare silicon nitride implants with PEEK cages filled with autograft harvested from osteophytes. The study is a prospective, randomized, blinded study of 100 patients with 2 years follow-up. The primary outcome measure was improvement in the Neck Disability Index. Other outcome measures included SF-36, VAS arm pain, VAS neck pain, assessment of recovery, operative characteristics, complications, fusion and subsidence based on dynamic X-ray and CT scan. There was no significant difference in NDI scores between the groups at 24 months follow-up. At 3 and 12 months the NDI scores were in favor of PEEK although the differences were not clinically relevant. On most follow-up moments there was no difference in VAS neck and VAS arm between both groups, and there was no statistically significant difference in patients' perceived recovery during follow-up. Fusion rate and subsidence were similar for the two study arms and about 90% of the implants were fused at 24 months. Patients treated with silicon nitride and PEEK reported similar recovery rates during follow-up. There was no significant difference in clinical outcome at 24 months. Fusion rates improved over time and are comparable between both groups.

  11. A Prospective Randomized Clinical Trial Comparing Bone Union Rate Following Anterior Cervical Discectomy and Fusion Using a Polyetheretherketone Cage: Hydroxyapatite/B-Tricalcium Phosphate Mixture versus Hydroxyapatite/Demineralized Bone Matrix Mixture.

    PubMed

    Yi, Jemin; Lee, Gun Woo; Nam, Woo Dong; Han, Kye Young; Kim, Myung-Ho; Kang, Jong Won; Won, Jonghwa; Kim, Seong Wan; Noh, Won; Yeom, Jin S

    2015-02-01

    Prospective randomized noninferiority trial. To evaluate whether the union rate of anterior cervical discectomy and fusion (ACDF) using a polyetheretherketone (PEEK) cage filled with a mixture of hydroxyapatite (HA) and demineralized bone matrix (DBM) is inferior to that of a mixture of β-tricalcium phosphate (β-TCP) and HA. There have been no clinical trials investigating the outcomes of a mixture of HA and DBM in a PEEK cage in ACDF. Eighty-five eligible patients were randomly assigned to group B (n=43), in which a PEEK cage with a mixture of HA and DBM was used, or group C (n=42), in which a PEEK cage with a mixture of HA and β-TCP was used. The primary study endpoint was the fusion rate, which was assessed with dynamic radiographs and computed tomography (CT) scans. Secondary endpoints included pain intensity using a visual analogue scale, functional outcome using a neck disability index score, laboratory tests of inflammatory profiles, and the infection rate. Seventy-seven patients (38 in group B and 39 in group C) were included in the final analysis. One year postoperatively, bone fusion was achieved in 87% of group B patients and 87% of group C patients on dynamic radiographs, and 87% of group B patients and 72% of group C patients on CT scans (p=1.00 and 0.16, respectively). There were also no between-groups differences with respect to the secondary endpoints. A HA/DBM mixture inside a PEEK cage can provide noninferior outcomes compared to a HA/TCP mixture in ACDF.

  12. A Prospective Randomized Clinical Trial Comparing Bone Union Rate Following Anterior Cervical Discectomy and Fusion Using a Polyetheretherketone Cage: Hydroxyapatite/B-Tricalcium Phosphate Mixture versus Hydroxyapatite/Demineralized Bone Matrix Mixture

    PubMed Central

    Yi, Jemin; Nam, Woo Dong; Han, Kye Young; Kim, Myung-Ho; Kang, Jong Won; Won, Jonghwa; Kim, Seong Wan; Noh, Won; Yeom, Jin S

    2015-01-01

    Study Design Prospective randomized noninferiority trial. Purpose To evaluate whether the union rate of anterior cervical discectomy and fusion (ACDF) using a polyetheretherketone (PEEK) cage filled with a mixture of hydroxyapatite (HA) and demineralized bone matrix (DBM) is inferior to that of a mixture of β-tricalcium phosphate (β-TCP) and HA. Overview of Literature There have been no clinical trials investigating the outcomes of a mixture of HA and DBM in a PEEK cage in ACDF. Methods Eighty-five eligible patients were randomly assigned to group B (n=43), in which a PEEK cage with a mixture of HA and DBM was used, or group C (n=42), in which a PEEK cage with a mixture of HA and β-TCP was used. The primary study endpoint was the fusion rate, which was assessed with dynamic radiographs and computed tomography (CT) scans. Secondary endpoints included pain intensity using a visual analogue scale, functional outcome using a neck disability index score, laboratory tests of inflammatory profiles, and the infection rate. Results Seventy-seven patients (38 in group B and 39 in group C) were included in the final analysis. One year postoperatively, bone fusion was achieved in 87% of group B patients and 87% of group C patients on dynamic radiographs, and 87% of group B patients and 72% of group C patients on CT scans (p=1.00 and 0.16, respectively). There were also no between-groups differences with respect to the secondary endpoints. Conclusions A HA/DBM mixture inside a PEEK cage can provide noninferior outcomes compared to a HA/TCP mixture in ACDF. PMID:25705332

  13. Cervical Stand-Alone Polyetheretherketone Cage versus Zero-Profile Anchored Spacer in Single-Level Anterior Cervical Discectomy and Fusion : Minimum 2-Year Assessment of Radiographic and Clinical Outcome

    PubMed Central

    Cho, Hyun-Jun; Hur, Junseok W.; Han, Jin-Sol; Cho, Tai-Hyoung; Park, Jung-Yul

    2015-01-01

    Objective We compared the clinical and radiographic outcomes of stand-alone polyetheretherketone (PEEK) cage and Zero-Profile anchored spacer (Zero-P) for single level anterior cervical discectomy and fusion (ACDF). Methods We retrospectively reviewed 121 patients who underwent single level ACDF within 2 years (Jan 2011-Jan 2013) in a single institute. Total 50 patients were included for the analysis who were evaluated more than 2-year follow-up. Twenty-nine patients were allocated to the cage group (m : f=19 : 10) and 21 for Zero-P group (m : f=12 : 9). Clinical (neck disability index, visual analogue scale arm and neck) and radiographic (Cobb angle-segmental and global cervical, disc height, vertebral height) assessments were followed at pre-operative, immediate post-operative, post-3, 6, 12, and 24 month periods. Results Demographic features and the clinical outcome showed no difference between two groups. The change between final follow-up (24 months) and immediate post-op of Cobb-segmental angle (p=0.027), disc height (p=0.002), vertebral body height (p=0.033) showed statistically better outcome for the Zero-P group than the cage group, respectively. Conclusion The Zero-Profile anchored spacer has some advantage after cage for maintaining segmental lordosis and lowering subsidence rate after single level anterior cervical discectomy and fusion. PMID:26361527

  14. Anterior cervical discectomy with fusion in patients with cervical disc degeneration: a prospective outcome study of 258 patients (181 fused with autologous bone graft and 77 fused with a PEEK cage)

    PubMed Central

    2010-01-01

    Background Anterior cervical discectomy with fusion (ACDF) is challenging with respect to both patient selection and choice of surgical procedure. The aim of this study was to evaluate the clinical outcome of ACDF, with respect to both patient selection and choice of surgical procedure: fusion with an autologous iliac crest graft (AICG) versus fusion with an artificial cage made of polyetheretherketone (PEEK). Methods This was a non-randomized prospective single-center outcome study of 258 patients who underwent ACDF for cervical disc degeneration (CDD). Fusion was attained with either tricortical AICG or PEEK cages without additional anterior plating, with treatment selected at surgeon's discretion. Radicular pain, neck-pain, headache and patient satisfaction with the treatment were scored using the visual analogue scale (VAS). Results The median age was 47.5 (28.3-82.8) years, and 44% of patients were female. 59% had single-level ACDF, 40% had two level ACDF and 1% had three-level ACDF. Of the patients, 181 were fused with AICG and 77 with a PEEK-cage. After surgery, the patients showed a significant reduction in radicular pain (ΔVAS = 3.05), neck pain (ΔVAS = 2.30) and headache (ΔVAS = 0.55). Six months after surgery, 48% of patients had returned to work: however 24% were still receiving workers' compensation. Using univariate and multivariate analyses we found that high preoperative pain intensity was significantly associated with a decrease in pain intensity after surgery, for all three pain categories. There were no significant correlations between pain relief and the following patient characteristics: fusion method (AICG or PEEK-cage), sex, age, number of levels fused, disc level fused, previous neck surgery (except for neck pain), previous neck trauma, or preoperative symptom duration. Two hundred out of the 256 (78%) patients evaluated the surgical result as successful. Only 27/256 (11%) classified the surgical result as a failure. Patient satisfaction

  15. Physical modification of polyetheretherketone for orthopedic implants

    NASA Astrophysics Data System (ADS)

    Du, Ya-Wei; Zhang, Li-Nan; Hou, Zeng-Tao; Ye, Xin; Gu, Hong-Sheng; Yan, Guo-Ping; Shang, Peng

    2014-12-01

    Polyetheretherketone (PEEK) is regarded as one of the most potential candidates for replacing current implant applications. To obtain good bone-implant interfaces, many modification methods have been developed to enable PEEK and PEEK-based composites from bio-inert to bioactive. Among them, physical methods have aroused significant attention and been widely used to modify PEEK for orthopedic implants. This review summarizes current physical modification techniques of PEEK for orthopedic applications, which include composite strategies, surface coating methods and irradiation treatments. The positive consequences of those modification methods will encourage continuing investigations and stimulate the wide range of applications of PEEK-based implants in orthopedics.

  16. Correction of a mandibular asymmetry after fibula reconstruction using a custom-made polyetheretherketone (PEEK) onlay after implant supported occlusal rehabilitation.

    PubMed

    Berrone, M; Aldiano, C; Pentenero, M; Berrone, S

    2015-10-01

    This study describes an unusual case of mandibular asymmetry after fibula free flap reconstruction in a young man following major facial trauma that was corrected using a custom-made polyetheretherketone prosthesis. There is little information in the literature on the use of alloplasts to correct mandibular asymmetry as interest in 'aesthetic re-modelling' has traditionally focused on nasal, zygomatic and chin regions. This report demonstrates that this technique can be used successfully to address selected cases of mandibular asymmetry.

  17. The rate of successful four-corner arthrodesis with a locking, dorsal circular polyether-ether-ketone (PEEK-Optima) plate.

    PubMed

    Rhee, P C; Shin, A Y

    2013-09-01

    The purpose of this study is to evaluate the rate of union after four-corner arthrodesis with a locking, dorsal circular plate comprised of polyether-ether-ketone. A retrospective review was conducted of all patients who underwent four-corner arthrodesis with a locking, dorsal circular plate at our institution from January 2005 to May 2009. The primary outcome measure was radiographic and clinical union. During the study period, 26 consecutive wrists underwent four-corner arthrodesis with a locking, dorsal circular plate. Twenty-three wrists were included. The mean clinical follow-up was 16 months (range 3-37). Union was achieved in 22 of 23 wrists at a mean time of 3 months (range 1-12). There was one partial union that underwent successful revision arthrodesis. In summary, four-corner fusion with a polyether-ether-ketone locking, dorsal circular plate results in high union rates. The use of a radiolucent plate allows for more accurate assessment of union with the biomechanical advantages of a fixed angle construct.

  18. Two-level anterior cervical discectomy and fusion using self-locking stand-alone polyetheretherketone cages with two anchoring clips placed in the upper and lower vertebrae, respectively.

    PubMed

    Luo, Jiaquan; Huang, Sheng; Gong, Ming; Li, Liangping; Yu, Ting; Zou, Xuenong

    2015-07-01

    Anterior cervical discectomy and fusion (ACDF) is a widely accepted surgical procedure for the treatment of cervical degenerative disk diseases (CDDD). The purpose of our study was to investigate the reliability and efficacy of ACDF using self-locking stand-alone polyetheretherketone (PEEK) cages, with two anchoring clips placed in the upper and lower vertebrae, respectively. Twenty-six patients who underwent ACDF using a stand-alone PEEK cage packed with local osteophytes and cancellous allograft bone from January 2010 to January 2012 were enrolled in this study. Clinical findings were assessed using a visual analog scale (VAS), Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), and Odom criteria. Intervertebral height and cervical fusion status were assessed on X-ray. Twenty-six patients underwent ACDF using a stand-alone PEEK cervical cage. All patients had a minimum 2 years of follow-up. The operative levels were C3/4, C4/5 in seven patients, C4/5, C5/6 in 13 patients, and C4/5, C6/7 in six patients. At 3 days, 6 months, and 2 years of follow-ups, the JOA scores were 10.41 ± 1.67, 13.78 ± 1.91, 14.42 ± 2.09, respectively, which was significantly higher (p < 0.01) than preoperative (7.34 ± 1.71), whereas VAS overall pain score was 4.35 ± 1.32, 1.73 ± 0.44, 1.32 ± 0.57, respectively, which was significantly lower (p < 0.01) than preoperative (8.01 ± 1.16). The NDI preoperatively was 33.94 ± 11.75, 23.53 ± 10.92 at 3 days postoperatively, 12.64 ± 8.36 at 6 months, and 10.74 ± 7.92 at 2 years of follow-ups. Intervertebral height was 5.99 ± 0.31 mm preoperatively, 8.70 ± 0.23 mm at 3 days, 8.34 ± 0.61 mm at 6 months, and 8.22 ± 0.35 mm at 2 years of follow-ups. According to Odom criteria, 10 patients (38.4%) presented with an excellent clinical outcome, 15 good (57.6%), 1 fair (3.8%), and no patient presented a poor outcome. Solid fusion was achieved in all patients (100%) at a mean time of 4.5 months. ACDF using a self

  19. Fracture resistance of abutment screws made of titanium, polyetheretherketone, and carbon fiber-reinforced polyetheretherketone.

    PubMed

    Neumann, Eduardo Aloisio Fleck; Villar, Cristina Cunha; França, Fabiana Mantovani Gomes

    2014-01-01

    Fractured abutment screws may be replaced; however, sometimes, the screw cannot be removed and the entire implant must be surgically removed and replaced. The aim of this study was to compare the fracture resistance of abutment retention screws made of titanium, polyetheretherketone (PEEK) and 30% carbon fiber-reinforced PEEK, using an external hexagonal implant/UCLA-type abutment interface assembly. UCLA-type abutments were fixed to implants using titanium screws (Group 1), polyetheretherketone (PEEK) screws (Group 2), and 30% carbon fiber-reinforced PEEK screws (Group 3). The assemblies were placed on a stainless steel holding apparatus to allow for loading at 45o off-axis, in a universal testing machine. A 200 N load (static load) was applied at the central point of the abutment extremity, at a crosshead speed of 5 mm/minute, until failure. Data was analyzed by ANOVA and Tukey's range test. The titanium screws had higher fracture resistance, compared with PEEK and 30% carbon fiber-reinforced PEEK screws (p < 0.05). In contrast, no statistically significant difference was observed between the fracture resistance of the PEEK and the 30% carbon fiber-reinforced PEEK screws (p> 0.05). Finally, visual analysis of the fractions revealed that 100% of them occurred at the neck of the abutment screw, suggesting that this is the weakest point of this unit. PEEK abutment screws have lower fracture resistance, in comparison with titanium abutment screws.

  20. PEEK Cages versus PMMA Spacers in Anterior Cervical Discectomy: Comparison of Fusion, Subsidence, Sagittal Alignment, and Clinical Outcome with a Minimum 1-Year Follow-Up

    PubMed Central

    Krüger, Marie T.; Sircar, Ronen; Kogias, Evangelos; Scholz, Christoph; Volz, Florian; Scheiwe, Christian; Hubbe, Ulrich

    2014-01-01

    Purpose. To compare radiographic and clinical outcomes after anterior cervical discectomy in patients with cervical degenerative disc disease using PEEK cages or PMMA spacers with a minimum 1-year follow-up. Methods. Anterior cervical discectomy was performed in 107 patients in one or two levels using empty PEEK cages (51 levels), Sulcem PMMA spacers (49 levels) or Palacos PMMA spacers (41 levels) between January, 2005 and February, 2009. Bony fusion, subsidence, and sagittal alignment were retrospectively assessed in CT scans and radiographs at follow-up. Clinical outcome was measured using the VAS, NDI, and SF-36. Results. Bony fusion was assessed in 65% (PEEK cage), 57% (Sulcem), and 46% (Palacos) after a mean follow-up of 2.5 years. Mean subsidence was 2.3–2.6 mm without significant differences between the groups. The most pronounced loss of lordosis was found in PEEK cages (−4.1°). VAS was 3.1 (PEEK cage), 3.6 (Sulcem), and 2.7 (Palacos) without significant differences. Functional outcome in the PEEK cage and Palacos group was superior to the Sulcem group. Conclusions. The substitute groups showed differing fusion rates. Clinical outcome, however, appears to be generally not correlated with fusion status or subsidence. We could not specify a superior disc substitute for anterior cervical discectomy. This trial is registered with DRKS00003591. PMID:25110734

  1. Are PEEK-on-Ceramic Bearings an Option for Total Disc Arthroplasty? An In Vitro Tribology Study.

    PubMed

    Siskey, Ryan; Ciccarelli, Lauren; Lui, Melissa K C; Kurtz, Steven M

    2016-11-01

    Most contemporary total disc replacements (TDRs) use conventional orthopaedic bearing couples such as ultrahigh-molecular-weight polyethylene (polyethylene) and cobalt-chromium (CoCr). Cervical total disc replacements incorporating polyetheretherketone (PEEK) bearings (specifically PEEK-on-PEEK bearings) have been previously investigated, but little is known about PEEK-on-ceramic bearings for TDR. (1) What is the tribologic behavior of a PEEK-on-ceramic bearing for cervical TDR under idealized, clean wear test conditions? (2) How does the PEEK-on-ceramic design perform under impingement conditions? (3) How is the PEEK-on-ceramic bearing affected by abrasive wear? (4) Is the particle morphology from PEEK-on-ceramic bearings for TDRs affected by adverse wear scenarios? PEEK-on-ceramic cervical TDR bearings were subjected to a 10 million cycle ideal wear test based on ASTM F2423 and ISO 181912-1 using a six-station spine wear simulator (MTS, Eden Prairie, MN, USA) with 5 g/L bovine serum concentration at 23° ± 2° C (ambient temperature). Validated 1 million cycle impingement and 5 million cycle abrasive tests were conducted on the PEEK-on-ceramic bearings based, in part, on retrieval analysis of a comparable bearing design as well as finite element analyses. The ceramic-on-PEEK couple was characterized for damage modes, mass and volume loss, and penetration and the lubricant was subjected to particle analysis. The resulting mass wear rate, volumetric wear rate, based on material density, and particle analysis were compared with clinically available cervical disc bearing couples. The three modes of wear (idealized, impingement, and abrasive) resulted in mean mass wear rates of 0.9 ± 0.2 mg/MC, 1.9 ± 0.5 mg/MC, and 2.8 ± 0.6 mg/MC, respectively. The mass wear rates were converted to volumetric wear rates using density and found to be 0.7 ± 0.1 mm(3)/MC, 1.5 ± 0.4 mm(3)/MC, and 2.1 ± 0.5 mm(3)/MC, respectively. During each test, the PEEK

  2. Efficacy of PEEK Cages and Plate Augmentation in Three-Level Anterior Cervical Fusion of Elderly Patients

    PubMed Central

    Song, Kyung Jin; Kim, Gyu Hyung

    2011-01-01

    Background To evaluate the clinical efficacy of three-level anterior cervical arthrodesis with polyethyletherketone (PEEK) cages and plate fixation for aged and osteoporotic patients with degenerative cervical spinal disorders. Methods Twenty one patients, who had undergone three-level anterior cervical arthrodesis with a cage and plate construct for degenerative cervical spinal disorder from November 2001 to April 2007 and were followed up for at least two years, were enrolled in this study. The mean age was 71.7 years and the mean T-score using the bone mineral density was -2.8 SD. The fusion rate, change in cervical lordosis, adjacent segment degeneration were analyzed by plain radiographs and computed tomography, and the complications were assessed by the medical records. The clinical outcomes were analyzed using the SF-36 physical composite score (PCS) and neck disability index (NDI). Results Radiological fusion was observed at a mean of 12.3 weeks (range, 10 to 15 weeks) after surgery. The average angle of cervical lordosis was 5° preoperatively, 17.6° postoperatively and 16.5° at the last follow-up. Degenerative changes in the adjacent segments occurred in 3 patients (14.3%), but revision surgery was unnecessary. In terms of instrument-related complications, there was cage subsidence in 5 patients (23.8%) with an average of 2.8 mm, and loosening of the plate and screw occurred in 3 patients (14.3%) but there were no clinical problems. The SF-36 PCS before surgery, second postoperative week and at the last follow-up was 29.5, 43.1, and 66.2, respectively. The respective NDI was 55.3, 24.6, and 15.9. Conclusions For aged and osteoporotic patients with degenerative cervical spinal disorders, three-level anterior cervical arthrodesis with PEEK cages and plate fixation reduced the pseudarthrosis and adjacent segment degeneration and improved the clinical outcomes. This method is considered to be a relatively safe and effective treatment modality. PMID:21369473

  3. Efficacy of PEEK cages and plate augmentation in three-level anterior cervical fusion of elderly patients.

    PubMed

    Song, Kyung Jin; Kim, Gyu Hyung; Choi, Byeong Yeol

    2011-03-01

    To evaluate the clinical efficacy of three-level anterior cervical arthrodesis with polyethyletherketone (PEEK) cages and plate fixation for aged and osteoporotic patients with degenerative cervical spinal disorders. Twenty one patients, who had undergone three-level anterior cervical arthrodesis with a cage and plate construct for degenerative cervical spinal disorder from November 2001 to April 2007 and were followed up for at least two years, were enrolled in this study. The mean age was 71.7 years and the mean T-score using the bone mineral density was -2.8 SD. The fusion rate, change in cervical lordosis, adjacent segment degeneration were analyzed by plain radiographs and computed tomography, and the complications were assessed by the medical records. The clinical outcomes were analyzed using the SF-36 physical composite score (PCS) and neck disability index (NDI). Radiological fusion was observed at a mean of 12.3 weeks (range, 10 to 15 weeks) after surgery. The average angle of cervical lordosis was 5° preoperatively, 17.6° postoperatively and 16.5° at the last follow-up. Degenerative changes in the adjacent segments occurred in 3 patients (14.3%), but revision surgery was unnecessary. In terms of instrument-related complications, there was cage subsidence in 5 patients (23.8%) with an average of 2.8 mm, and loosening of the plate and screw occurred in 3 patients (14.3%) but there were no clinical problems. The SF-36 PCS before surgery, second postoperative week and at the last follow-up was 29.5, 43.1, and 66.2, respectively. The respective NDI was 55.3, 24.6, and 15.9. For aged and osteoporotic patients with degenerative cervical spinal disorders, three-level anterior cervical arthrodesis with PEEK cages and plate fixation reduced the pseudarthrosis and adjacent segment degeneration and improved the clinical outcomes. This method is considered to be a relatively safe and effective treatment modality.

  4. [After titanium, peek ?].

    PubMed

    Meningaud, J-P; Spahn, F; Donsimoni, J-M

    2012-11-01

    The PEEK-Optima(®), composite mixture of polyetheretherketon and inert materials, is used in orthopedics, spinal surgery and cranio-facial surgery. It could be used in dental implantology because of its biological and mechanical properties. The results of an experimental and finite element study made on basal implant prototypes, on basal implantology show that PEEK, contrary to titanium, has a compound structure that allows to optimize the distribution of masticatory forces around the implant. These results should be confirmed by a clinical study according to research regulation.

  5. Current Strategies to Improve the Bioactivity of PEEK

    PubMed Central

    Ma, Rui; Tang, Tingting

    2014-01-01

    The synthetic thermoplastic polymer polyetheretherketone (PEEK) is becoming a popular component of clinical orthopedic and spinal applications, but its practical use suffers from several limitations. Although PEEK is biocompatible, chemically stable, radiolucent and has an elastic modulus similar to that of normal human bone, it is biologically inert, preventing good integration with adjacent bone tissues upon implantation. Recent efforts have focused on increasing the bioactivity of PEEK to improve the bone-implant interface. Two main strategies have been used to overcome the inert character of PEEK. One approach is surface modification to activate PEEK through surface treatment alone or in combination with a surface coating. Another strategy is to prepare bioactive PEEK composites by impregnating bioactive materials into PEEK substrate. Researchers believe that modified bioactive PEEK will have a wide range of orthopedic applications. PMID:24686515

  6. Does partial coating with titanium improve the radiographic fusion rate of empty PEEK cages in cervical spine surgery? A comparative analysis of clinical data.

    PubMed

    Kotsias, Andreas; Mularski, Sven; Kühn, Björn; Hanna, Michael; Suess, Olaf

    2017-01-01

    Anterior cervical diskectomy and fusion (ACDF) is a well-established surgical treatment. Several types of intervertebral spacers can be used, but there is increasing evidence that PEEK cages yield insufficient fusion and thus less clinical improvement. The study aim was to assess the outcomes of single-level ACDF with an empty PEEK cage partially coated with titanium. This prospective multicenter single-arm clinical study collected follow-up data at 6, 12, and 18 months. A post hoc comparison was made to closely matched patients from another similar trial treated with identically designed, empty, uncoated PEEK cages. There were 49 of 50 patients (98%) who met the MCID of 3+ points of improvement on VAS pain or had an 18-month VAS ≤ 1. Yet even by 18 months post-op, only 40 of 50 (80%) PEEK + Ti patients achieved complete bony fusion. The PEEK + Ti group (n = 49) seemed to have somewhat better fusion scores and significantly better pain relief at 6 M than the matched controls (n = 49), but these differences did not persist at 12 M or 18 M. Patients (with either implant) who achieved complete bony fusion had significantly better improvement of pain at 6 M and disability at 6 M and 12 M than patients that remained unfused. ACDF is effective treatment for cervical myelopathy and radiculopathy. Although this and other studies show that titanium fuses better, partial coating of a PEEK cage does not improve the fusion rate sufficiently or confer other lasting clinical benefit. PEEK cages fully coated with titanium should be tested in prospective randomized comparative trials. Prospective, multicenter, single-arm clinical observational study without an individual Trial registration number. Study design and post hoc data analysis according to the "PIERCE-PEEK study", ISRCTN42774128, retrospectively registered 14 April 2009.

  7. Influence of Layer Thickness and Raster Angle on the Mechanical Properties of 3D-Printed PEEK and a Comparative Mechanical Study between PEEK and ABS

    PubMed Central

    Wu, Wenzheng; Geng, Peng; Li, Guiwei; Zhao, Di; Zhang, Haibo; Zhao, Ji

    2015-01-01

    Fused deposition modeling (FDM) is a rapidly growing 3D printing technology. However, printing materials are restricted to acrylonitrile butadiene styrene (ABS) or poly (lactic acid) (PLA) in most Fused deposition modeling (FDM) equipment. Here, we report on a new high-performance printing material, polyether-ether-ketone (PEEK), which could surmount these shortcomings. This paper is devoted to studying the influence of layer thickness and raster angle on the mechanical properties of 3D-printed PEEK. Samples with three different layer thicknesses (200, 300 and 400 μm) and raster angles (0°, 30° and 45°) were built using a polyether-ether-ketone (PEEK) 3D printing system and their tensile, compressive and bending strengths were tested. The optimal mechanical properties of polyether-ether-ketone (PEEK) samples were found at a layer thickness of 300 μm and a raster angle of 0°. To evaluate the printing performance of polyether-ether-ketone (PEEK) samples, a comparison was made between the mechanical properties of 3D-printed polyether-ether-ketone (PEEK) and acrylonitrile butadiene styrene (ABS) parts. The results suggest that the average tensile strengths of polyether-ether-ketone (PEEK) parts were 108% higher than those for acrylonitrile butadiene styrene (ABS), and compressive strengths were 114% and bending strengths were 115%. However, the modulus of elasticity for both materials was similar. These results indicate that the mechanical properties of 3D-printed polyether-ether-ketone (PEEK) are superior to 3D-printed ABS. PMID:28793537

  8. Influence of Layer Thickness and Raster Angle on the Mechanical Properties of 3D-Printed PEEK and a Comparative Mechanical Study between PEEK and ABS.

    PubMed

    Wu, Wenzheng; Geng, Peng; Li, Guiwei; Zhao, Di; Zhang, Haibo; Zhao, Ji

    2015-09-01

    Fused deposition modeling (FDM) is a rapidly growing 3D printing technology. However, printing materials are restricted to acrylonitrile butadiene styrene (ABS) or poly (lactic acid) (PLA) in most Fused deposition modeling (FDM) equipment. Here, we report on a new high-performance printing material, polyether-ether-ketone (PEEK), which could surmount these shortcomings. This paper is devoted to studying the influence of layer thickness and raster angle on the mechanical properties of 3D-printed PEEK. Samples with three different layer thicknesses (200, 300 and 400 μm) and raster angles (0°, 30° and 45°) were built using a polyether-ether-ketone (PEEK) 3D printing system and their tensile, compressive and bending strengths were tested. The optimal mechanical properties of polyether-ether-ketone (PEEK) samples were found at a layer thickness of 300 μm and a raster angle of 0°. To evaluate the printing performance of polyether-ether-ketone (PEEK) samples, a comparison was made between the mechanical properties of 3D-printed polyether-ether-ketone (PEEK) and acrylonitrile butadiene styrene (ABS) parts. The results suggest that the average tensile strengths of polyether-ether-ketone (PEEK) parts were 108% higher than those for acrylonitrile butadiene styrene (ABS), and compressive strengths were 114% and bending strengths were 115%. However, the modulus of elasticity for both materials was similar. These results indicate that the mechanical properties of 3D-printed polyether-ether-ketone (PEEK) are superior to 3D-printed ABS.

  9. Polyetheretherketone/nano-fluorohydroxyapatite composite with antimicrobial activity and osseointegration properties.

    PubMed

    Wang, Lixin; He, Shu; Wu, Xiaomian; Liang, Shanshan; Mu, Zhonglin; Wei, Jie; Deng, Feng; Deng, Yi; Wei, Shicheng

    2014-08-01

    Lack of antibacterial activity and binding ability to natural bone tissue has significantly limited polyetheretherketone (PEEK) for many challenging dental implant applications. Here, we have developed a polyetheretherketone/nano-fluorohydroxyapatite (PEEK/nano-FHA) biocomposite with enhanced antibacterial activity and osseointegration through blending method. Smooth and rough surfaces of PEEK/nano-FHA biocomposites were also prepared. Our results showed that in vitro initial cell adhesion and proliferation on the nano-FHA reinforced PEEK composite were improved. In addition, higher alkaline phosphatase activity and cell mineralization were also detected in cells cultured on PEEK/nano-FHA biocomposites, especially for rough PEEK/nano-FHA surfaces. More importantly, the as-prepared PEEK/nano-FHA biocomposite could effectively prevent the proliferation and biofilm formation of bacterial. For in vivo test, the newly formed bone volume of PEEK/nano-FHA group was higher than that of bare PEEK group based on 3D microcomputed tomography and 2D histomorphometric analysis. These reports demonstrate that the developed PEEK/nano-FHA biocomposite has increased biocompatibility and antibacterial activity in vitro, and promoted osseointegration in vivo, which suggests that it holds potential to be applied as dental implant material in dental tissue engineering applications.

  10. Bioactive carbon-PEEK composites prepared by chemical surface treatment.

    PubMed

    Miyazaki, Toshiki; Matsunami, Chisato; Shirosaki, Yuki

    2017-01-01

    Polyetheretherketone (PEEK) has attracted much attention as an artificial intervertebral spacer for spinal reconstruction. Furthermore, PEEK plastic reinforced with carbon fiber has twice the bending strength of pure PEEK. However, the PEEK-based materials do not show ability for direct bone bonding, i.e., bioactivity. Although several trials have been conducted for enabling PEEK with bioactivity, few studies have reported on bioactive surface modification of carbon-PEEK composites. In the present study, we attempted the preparation of bioactive carbon-PEEK composites by chemical treatments with H2SO4 and CaCl2. Bioactivity was evaluated by in vitro apatite formation in simulated body fluid (SBF). The apatite formation on the carbon-PEEK composite was compared with that of pure PEEK. Both pure PEEK and carbon-PEEK composite formed the apatite in SBF when they were treated with H2SO4 and CaCl2; the latter showed higher apatite-forming ability than the former. It is conjectured that many functional groups able to induce the apatite nucleation, such as sulfo and carboxyl groups, are incorporated into the dispersed carbon phase in the carbon-PEEK composites.

  11. Investigation of microstructural changes in polyetherether-ketone films at cryogenic temperatures by positron lifetime spectroscopy

    NASA Technical Reports Server (NTRS)

    Singh, Jag J.; Eftekhari, Abe; St.clair, Terry L.; Sprinkle, Danny R.

    1991-01-01

    Microstructural changes in Polyetherether-ketone (PEEK) films were investigated in the temperature ranges of 23 to -196 C, using Positron Lifetime Spectroscopy (PLS) technique. It was determined that the total free volume decreases by about 46 percent in amorphous PEEK samples and about 36 percent in semicrystalline PEEK samples when they are cooled down from room temperature to liquid nitrogen (LN2) temperature. If this trend in reduction in free volume with decreasing temperature continues, as expected, it is surmised that PEEK will be able to withstand cooling down to liquid hydrogen (LH2) temperature without any detrimental effect on its diffusivity for liquid hydrogen.

  12. The use of self-mating PEEK as an alternative bearing material for cervical disc arthroplasty: a comparison of different simulator inputs and tribological environments.

    PubMed

    Brown, Tim; Bao, Qi-Bin

    2012-06-01

    The hypothesis for this study was that the simulated wear behavior of a hydroxyapatite coated, self-mating PEEK cervical disc arthroplasty device would be dependent on the simulated testing environment. Five groups of devices were evaluated under suggested ASTM and ISO load and motion profiles. The groups utilized different testing frequencies and protein content of simulator fluid, in addition to assessing the potential for third body wear. The average wear rates were determined using linear regression analysis with a generalized estimating equation. Significant differences between groups were determined using the Wald's test. The simulated wear behavior was shown to be highly dependent on the testing environment, where protein content more than decreasing the cyclic loading frequency resulted in increased wear, but was not dependent on the suggested load and motion profiles. It was demonstrated that a self-mating PEEK cervical disc arthroplasty device has wear rates that are similar to existing material combinations for cervical disc arthroplasty. This study showed that at a time when data from retrieval analyses is deficient, it is important to test the wear resistance of cervical disc arthroplasty devices under various conditions. Long-term clinical results and ongoing implant retrievals are required for validation between clinical performance and simulator inputs.

  13. Stress shielding and fatigue limits of poly-ether-ether-ketone dental implants.

    PubMed

    Lee, Woo-Taek; Koak, Jai-Young; Lim, Young-Jun; Kim, Seong-Kyun; Kwon, Ho-Beom; Kim, Myung-Joo

    2012-05-01

    The poly-ether-ether-ketone (PEEK) polymer is of great interest as an alternative to titanium in orthopedics because of its biocompatibility and low elastic modulus. This study evaluated the fatigue limits of PEEK and the effects of the low elastic modulus PEEK in relation to existing dental implants. Compressive loading tests were performed with glass fiber-reinforced PEEK (GFR-PEEK), carbon fiber-reinforced PEEK (CFR-PEEK), and titanium rods. Among these tests, GFR-PEEK fatigue tests were performed according to ISO 14801. For the finite element analysis, three-dimensional models of dental implants and bone were constructed. The implants in the test groups were coated with a 0.5-mm thick and 5-mm long PEEK layer on the upper intrabony area. The strain energy densities (SED) were calculated, and the bone resorption was predicted. The fatigue limits of GFR-PEEK were 310 N and were higher than the static compressive strength of GFR-PEEK. The bone around PEEK-coated implants showed higher levels of SED than the bone in direct contact with the implants, and the wider diameter and stiffer implants showed lower levels of SED. The compressive strength of the GFR-PEEK and CFR-PEEK implants ranged within the bite force of the anterior and posterior dentitions, respectively, and the PEEK implants showed adequate fatigue limits for replacing the anterior teeth. Dental implants with PEEK coatings and PEEK implants may reduce stress shielding effects. Dental implant application of PEEK polymer-fatigue limit and stress shielding. Copyright © 2012 Wiley Periodicals, Inc.

  14. PEEK dental implants: a review of the literature.

    PubMed

    Schwitalla, Andreas; Müller, Wolf-Dieter

    2013-12-01

    The insertion of dental implants containing titanium can be associated with various complications (eg, hypersensitivity to titanium). The aim of this article is to evaluate whether there are existing studies reporting on PEEK (polyetheretherketone) as an alternative material for dental implants. A systematic literature search of PubMed until December 2010 yielded 3 articles reporting on dental implants made from PEEK. One article analyzed stress distribution in carbon fiber-reinforced PEEK (CFR-PEEK) dental implants by the 3-dimensional finite element method, demonstrating higher stress peaks due to a reduced stiffness compared to titanium. Two articles reported on investigations in mongrel dogs. The first article compared CFR-PEEK to titanium-coated CFR-PEEK implants, which were inserted into the femurs and evaluated after 4 and 8 weeks. The titanium-coated implants showed significantly higher bone-implant contact (BIC) rates. In a second study, implants of pure PEEK were inserted into the mandibles beside implants made from titanium and zirconia and evaluated after 4 months, where PEEK presented the lowest BIC. The existing articles reporting on PEEK dental implants indicate that PEEK could represent a viable alternative material for dental implants. However, further experimental studies on the chemical modulation of PEEK seem to be necessary, mainly to increase the BIC ratio and to minimize the stress distribution to the peri-implant bone.

  15. In vitro biocompatibility of polyetheretherketone and polysulfone composites.

    PubMed

    Wenz, L M; Merritt, K; Brown, S A; Moet, A; Steffee, A D

    1990-02-01

    Short carbon fiber reinforced composites could potentially replace some of the metal alloys used in orthopedic implants. In particular, polysulfone and, more recently, polyetheretherketone have been considered as the matrix material for carbon fiber reinforced composite implant materials. ASTM standards F813 and F619 for direct contact cell culture evaluation and extraction were employed to determine the in vitro biocompatibility of a carbon fiber composite of polyetheretherketone, PEEK, in comparison to a carbon fiber reinforced polysulfone composite. The cell cultures were assessed qualitatively by microscopy and quantitatively using an enzyme assay to determine cytotoxicity. Overall, the cellular response to the PEEK and polysulfone composites were negligible indicating that further in vivo studies with these materials are appropriate.

  16. Preliminary Experiences of the Combined Midline-Splitting French Door Laminoplasty with Polyether Ether Ketone (PEEK) Plate for Cervical Spondylosis and OPLL

    PubMed Central

    Oh, Chang Hyun; Ji, Gyu Yeul; Hur, Junseok W.; Choi, Won-Seok; Shin, Dong Ah

    2015-01-01

    Objective The purpose of this study was to evaluate the safety and efficacy of cervical midline-splitting French-door laminoplasty with a polyether ether ketone (PEEK) plate. The authors retrospectively analyzed the results of patients with cervical laminoplasty miniplate (MAXPACER®) without bone grafts in multilevel cervical stenosis. Methods Fifteen patients (13 males and 2 females, mean age 50.0 years (range 35-72)) with multilevel cervical stenosis (ossification of the posterior longitudinal ligament and cervical spondylotic myelopathy) underwent a combined surgery of midline-splitting French-door laminoplasty with or without mini plate. All 15 patients were followed for at least 12 months (mean follow-up 13.3 months) after surgery, and a retrospective review of the clinical, radiological and surgical data was conducted. Results The radiographic results showed a significant increase over the postoperative period in anterior-posterior diameter (9.4±2.2 cm to 16.2±1.1 cm), open angles in cervical lamina (46.5±16.0° to 77.2±13.1°), and sectional volume of cervical central canal (100.5±0.7 cm2 to 146.5±4.9 cm2) (p<0.001). The sagittal alignment of the cervical spine was well preserved (31.7±10.0° to 31.2±7.6°, p=0.877) during the follow-up period. The clinical results were successful, and there were no significant intraoperative complications except for screw displacement in two cases. The mini plate constructs did not fail during the 12 month follow-up period, and the decompression was maintained. Conclusion Despite the small cohort and short follow-up duration, the present study demonstrated that combined cervical expansive laminoplasty using the mini plate is an effective treatment for multilevel cervical stenosis. PMID:26217382

  17. Biomechanical stability of a bioabsorbable self-retaining polylactic acid/nano-sized β-tricalcium phosphate cervical spine interbody fusion device in single-level anterior cervical discectomy and fusion sheep models.

    PubMed

    Cao, Lu; Duan, Ping-Guo; Li, Xi-Lei; Yuan, Feng-Lai; Zhao, Ming-Dong; Che, Wu; Wang, Hui-Ren; Dong, Jian

    2012-01-01

    The aim of this study was to investigate the biomechanical stability provided by a novel, polylactic acid/nano-sized, β-tricalcium phosphate, bioabsorbable, self-retaining cervical fusion cage (BCFC). Quasistatic nonconstraining torques (maximum 1.5 NM) induced flexion, extension, lateral bending (±1.5 NM), and axial rotation (±1.5 NM) on 32 sheep cervical spines (C2-C5). The motion segment C3-C4 was first tested intact; the following groups were tested after complete discectomy: autologous tricortical iliac crest bone graft, Medtronic-Wego polyetheretherketone (PEEK) cage, Solis PEEK cage, and BCFC. The autologous bone graft group was tested with an anterior plate. The mean range of motion (ROM) was calculated from the load-displacement curves. BCFC significantly decreased ROM in lateral bending and axial rotation compared to other implants, and no significant difference in ROM between two types of PEEK cages and BCFC could be observed in flexion and extension. Anterior cervical plate (ACP) significantly decreased ROM in flexion and extension, but no significant difference in ROM between BCFC and bone graft plus ACP could be determined in lateral bending and axial rotation. The BCFC device showed better stability to autologous tricortical iliac crest bone graft and PEEK cages in single-level anterior cervical discectomy and fusion models and thus may be a potential alternative to the current PEEK cages.

  18. Biomechanical stability of a bioabsorbable self-retaining polylactic acid/nano-sized β-tricalcium phosphate cervical spine interbody fusion device in single-level anterior cervical discectomy and fusion sheep models

    PubMed Central

    Cao, Lu; Duan, Ping-Guo; Li, Xi-Lei; Yuan, Feng-Lai; Zhao, Ming-Dong; Che, Wu; Wang, Hui-Ren; Dong, Jian

    2012-01-01

    Purpose The aim of this study was to investigate the biomechanical stability provided by a novel, polylactic acid/nano-sized, β-tricalcium phosphate, bioabsorbable, self-retaining cervical fusion cage (BCFC). Methods Quasistatic nonconstraining torques (maximum 1.5 NM) induced flexion, extension, lateral bending (±1.5 NM), and axial rotation (±1.5 NM) on 32 sheep cervical spines (C2–C5). The motion segment C3–C4 was first tested intact; the following groups were tested after complete discectomy: autologous tricortical iliac crest bone graft, Medtronic–Wego polyetheretherketone (PEEK) cage, Solis PEEK cage, and BCFC. The autologous bone graft group was tested with an anterior plate. The mean range of motion (ROM) was calculated from the load-displacement curves. Results BCFC significantly decreased ROM in lateral bending and axial rotation compared to other implants, and no significant difference in ROM between two types of PEEK cages and BCFC could be observed in flexion and extension. Anterior cervical plate (ACP) significantly decreased ROM in flexion and extension, but no significant difference in ROM between BCFC and bone graft plus ACP could be determined in lateral bending and axial rotation. Conclusion The BCFC device showed better stability to autologous tricortical iliac crest bone graft and PEEK cages in single-level anterior cervical discectomy and fusion models and thus may be a potential alternative to the current PEEK cages. PMID:23226018

  19. Outcomes Evaluation of Zero-Profile Devices Compared to Stand-Alone PEEK Cages for the Treatment of Three- and Four-Level Cervical Disc Disease

    PubMed Central

    Paschel, Erin; Mashaly, Hazem; Sabry, Hatem; Jalalod'din, Hasan; Saoud, Khaled

    2016-01-01

    Background: Anterior cervical discectomy and fusion (ACDF) is a well-accepted treatment option for patients with cervical spine disease. Three- and four-level discectomies are known to be associated with a higher complication rate and lower fusion rate than single-level surgery. This study was performed to evaluate and compare zero-profile fixation and stand-alone PEEK cages for three- and four-level ACDF. Methods: Two cohorts of patients who underwent ACDF for the treatment of three- and four-level disease were compared. Thirty-three patients underwent implantation of zero-profile devices that included titanium screw fixation (Group A). Thirty-five patients underwent implantation of stand-alone PEEK cages without any form of screw fixation (Group B). Results: In Group A, twenty-seven patients underwent a three-level and six patients a four-level ACDF, with a total of 105 levels. In Group B, thirty patients underwent a three-level and five patients underwent a four-level ACDF, with a total number of 110 levels. In Group A, the mean preoperative visual analog scale score (VAS) for arm pain was 6.4 (range 3-8), and the mean postoperative VAS for arm pain decreased to 2.5 (range 1-7). In group B, the mean preoperative VAS of arm pain was 7.1 (range 3-10), and the mean postoperative VAS of arm pain decreased to 2 (range 0-4). In Group A, four patients (12%) developed dysphagia, and in Group B, three patients (9%) developed dysphagia.  Conclusions: This study found zero-profile instrumentation and PEEK cages to be both safe and effective for patients who underwent three- and four-level ACDF, comparable to reported series using plate devices. Rates of dysphagia for the cohort were much lower than reports using plate devices. Zero-profile segmental fixation devices and PEEK cages may be considered as viable alternatives over plate fixation for patients requiring multi-level anterior cervical fusion surgery. PMID:27738574

  20. Notch Sensitivity of PEEK in Monotonic Tension

    PubMed Central

    Sobieraj, MC; Kurtz, SM; Rimnac, CM

    2009-01-01

    Poly(ether-ether-ketone) (PEEK) has been used as a load bearing orthopaedic implant material with clinical success. All of the orthpaedic applications contain stress concentrations (notches) in their design; however, little work has been done to examine the stress-strain behavior of PEEK in the presence of a notch. This work examines both the stress-strain behavior and the fracture behavior of neat PEEK in a uniaxial loaded condition, and in circumferentially grooved round bar specimens with different elastic stress concentration factors. It was found that the material shows ductile necking in the smooth condition and that this is almost completely suppressed in the notched conditions. Additionally, the deformation and fracture micromechanisms changed drastically, from one of plastic deformation and void coalescence to one dominated by crazing and brittle fast fracture. This change in mechanism was explained via Neuber's theory of stresses at a notch. PMID:19733391

  1. Research on Tribological Behavior of PEEK and Glass Fiber Reinforced PEEK Composite

    NASA Astrophysics Data System (ADS)

    Li, E. Z.; Guo, W. L.; Wang, H. D.; Xu, B. S.; Liu, X. T.

    The tribological behaviors of pure polyetheretherketone (PEEK) and PEEK composites reinforced by 30wt% short glass fibers (GF) were comparatively evaluated on a ball-on-disc configuration at room temperature. The effects of applied load and sliding time on the friction coefficient and wear loss of the GF/PEEK were examined. The mechanical property, morphology and thermal performance of the composite were studied. The results indicated that the friction coefficient and wear loss of the composite increased gradually and tended to be a stable state as the increase of applied load and sliding time. The GF/PEEK has an excellent wear resistance, compared with PEEK. The SEM and EDS indicated that the short glass-fibers were extruded from the composite rather than pulverized into the composite. Compared with that of pure PEEK, the thermal decomposition temperature of GF/PEEK composite had an increase of 75 °C. The tensile strength and flexural strength of the composite were increased by 64% and 66%, respectively.

  2. Porous titanium-6 aluminum-4 vanadium cage has better osseointegration and less micromotion than a poly-ether-ether-ketone cage in sheep vertebral fusion.

    PubMed

    Wu, Su-Hua; Li, Yi; Zhang, Yong-Quan; Li, Xiao-Kang; Yuan, Chao-Fan; Hao, Yu-Lin; Zhang, Zhi-Yong; Guo, Zheng

    2013-12-01

    Interbody fusion cages made of poly-ether-ether-ketone (PEEK) have been widely used in clinics for spinal disorders treatment; however, they do not integrate well with surrounding bone tissue. Ti-6Al-4V (Ti) has demonstrated greater osteoconductivity than PEEK, but the traditional Ti cage is generally limited by its much greater elastic modulus (110 GPa) than natural bone (0.05-30 GPa). In this study, we developed a porous Ti cage using electron beam melting (EBM) technique to reduce its elastic modulus and compared its spinal fusion efficacy with a PEEK cage in a preclinical sheep anterior cervical fusion model. A porous Ti cage possesses a fully interconnected porous structure (porosity: 68 ± 5.3%; pore size: 710 ± 42 μm) and a similar Young's modulus as natural bone (2.5 ± 0.2 GPa). When implanted in vivo, the porous Ti cage promoted fast bone ingrowth, achieving similar bone volume fraction at 6 months as the PEEK cage without autograft transplantation. Moreover, it promoted better osteointegration with higher degree (2-10x) of bone-material binding, demonstrated by histomorphometrical analysis, and significantly higher mechanical stability (P < 0.01), shown by biomechanical testing. The porous Ti cage fabricated by EBM could achieve fast bone ingrowth. In addition, it had better osseointegration and superior mechanical stability than the conventional PEEK cage, demonstrating great potential for clinical application. © 2013 Wiley Periodicals, Inc. and International Center for Artificial Organs and Transplantation.

  3. The CASCADE trial: effectiveness of ceramic versus PEEK cages for anterior cervical discectomy with interbody fusion; protocol of a blinded randomized controlled trial.

    PubMed

    Arts, Mark P; Wolfs, Jasper F C; Corbin, Terry P

    2013-08-16

    Anterior cervical discectomy with interbody fusion cages is considered the standard surgical procedure in patients with cervical disc herniation. However, PEEK or metal cages have some undesirable imaging characteristics, leading to a search for alternative materials not creating artifacts on images; silicon nitride ceramic. Whether patients treated with silicon nitride ceramic cages have similar functional outcome as patients treated with PEEK cages is not known. We present the design of the CASCADE trial on effectiveness of ceramic cages versus PEEK cages in patients with cervical disc herniation and/or osteophytes. Patients (age 18-75 years) with monoradicular symptoms in one or both arms lasting more than 8 weeks, due to disc herniation and/or osteophytes, are eligible for the trial. The study is designed as a randomized controlled equivalence trial in which patients are blinded to the type of cage for 1 year. The total follow-up period is 2 years. The primary outcome measure is improvement in the Neck and Disability Index (NDI). Secondary outcomes measures include improvement in arm pain and neck pain (VAS), SF-36 and patients' perceived recovery. The final elements of comparison are perioperative statistics including operating time, blood loss, length of hospital stay, and adverse events. Lateral plane films at each follow-up visit and CT scan (at 6 months) will be used to judge fusion and the incidence of subsidence. Based on a power of 90% and assuming 8% loss to follow-up, 100 patients will be randomized into the 2 groups. The first analysis will be conducted when all patients have 1 year of follow-up, and the groups will be followed for 1 additional year to judge stability of outcomes. While the new ceramic cage has received the CE Mark based on standard compliance and animal studies, a randomized comparative study with the golden standard product will provide more conclusive information for clinicians. Implementation of any new device should only be done

  4. Notched Fatigue Behavior of PEEK

    PubMed Central

    Murphy, JE; Brinkman, JG; Kurtz, SM; Rimnac, CM

    2013-01-01

    Poly(ether-ether-ketone) (PEEK) has been used as a load bearing orthopaedic implant material with clinical success. All of the orthopaedic applications contain stress concentrations (notches) in their design; however, little work has been done to examine the fatigue behavior of PEEK in the presence of a notch. This work examines both stress-life (SN) fatigue behavior and the fracture behavior of unfilled PEEK under tension tension loading in circumferentially grooved round bar specimens with different elastic stress concentration factors. It was found that the majority of the loading was elastic in nature, and that there was only a small portion on the lifetime where there was a detectable change in structural behavior prior to gross fracture. Fractographic analysis via SEM further elucidated the potential fracture micromechanisms. Additional analysis was conducted to estimate the percent of the lifetime spent in crack initiation vs propagation, and it was found that the specimens spent the majority of the time in the crack initiation phase. PMID:20864160

  5. Osseointegration of nanohydroxyapatite- or nano-calcium silicate-incorporated polyetheretherketone bioactive composites in vivo.

    PubMed

    Ma, Rui; Yu, Zhifeng; Tang, Songchao; Pan, Yongkang; Wei, Jie; Tang, Tingting

    Polyetheretherketone (PEEK) exhibits appropriate biomechanical strength as well as good biocompatibility and stable chemical properties but lacks bioactivity and cannot achieve highly efficient osseointegration after implantation. Incorporating bioceramics into the PEEK matrix is a feasible approach for improving its bioactivity. In this study, nanohydroxyapatite (n-HA) and nano-calcium silicate (n-CS) were separately incorporated into PEEK to prepare n-HA/PEEK and n-CS/PEEK biocomposites, respectively, using a compounding and injection-molding technique, and the in vitro degradation characteristics were evaluated. Discs with a diameter of 8 mm were inserted in 8 mm full-thickness cranial defects in rabbits for 4 and 8 weeks, and implantation of pure PEEK was used as the control. Three-dimensional microcomputed tomography, histological analysis, fluorescence microscopy of new bone formation, and scanning electron microscopy were used to evaluate the osseointegration performance at the bone/implant interface. The results of the in vitro degradation study demonstrated that degradation of n-CS on the surface of n-CS/PEEK could release Ca and Si ions and form a porous structure. In vivo tests revealed that both n-CS/PEEK and n-HA/PEEK promoted osseointegration at the bone/implant interface compared to PEEK, and n-CS/PEEK exhibited higher bone contact ratio and more new bone formation compared with those of n-HA/PEEK, implying that n-CS/PEEK possessed a stronger ability to promote osseointegration. These two PEEK biocomposites are promising materials for the preparation of orthopedic or craniofacial implants.

  6. Osseointegration of nanohydroxyapatite- or nano-calcium silicate-incorporated polyetheretherketone bioactive composites in vivo

    PubMed Central

    Ma, Rui; Yu, Zhifeng; Tang, Songchao; Pan, Yongkang; Wei, Jie; Tang, Tingting

    2016-01-01

    Polyetheretherketone (PEEK) exhibits appropriate biomechanical strength as well as good biocompatibility and stable chemical properties but lacks bioactivity and cannot achieve highly efficient osseointegration after implantation. Incorporating bioceramics into the PEEK matrix is a feasible approach for improving its bioactivity. In this study, nanohydroxyapatite (n-HA) and nano-calcium silicate (n-CS) were separately incorporated into PEEK to prepare n-HA/PEEK and n-CS/PEEK biocomposites, respectively, using a compounding and injection-molding technique, and the in vitro degradation characteristics were evaluated. Discs with a diameter of 8 mm were inserted in 8 mm full-thickness cranial defects in rabbits for 4 and 8 weeks, and implantation of pure PEEK was used as the control. Three-dimensional microcomputed tomography, histological analysis, fluorescence microscopy of new bone formation, and scanning electron microscopy were used to evaluate the osseointegration performance at the bone/implant interface. The results of the in vitro degradation study demonstrated that degradation of n-CS on the surface of n-CS/PEEK could release Ca and Si ions and form a porous structure. In vivo tests revealed that both n-CS/PEEK and n-HA/PEEK promoted osseointegration at the bone/implant interface compared to PEEK, and n-CS/PEEK exhibited higher bone contact ratio and more new bone formation compared with those of n-HA/PEEK, implying that n-CS/PEEK possessed a stronger ability to promote osseointegration. These two PEEK biocomposites are promising materials for the preparation of orthopedic or craniofacial implants. PMID:27881916

  7. Reinforcement of polyetheretherketone polymer with titanium for improved mechanical properties and in vitro biocompatibility.

    PubMed

    Jung, Hyun-Do; Park, Hui-Sun; Kang, Min-Ho; Li, Yuanlong; Kim, Hyoun-Ee; Koh, Young-Hag; Estrin, Yuri

    2016-01-01

    Blends of ductile Ti metal with polyetheretherketone (PEEK) polymer were studied with regard to their mechanical properties and in vitro biocompatibility. PEEK/Ti composites with various Ti contents, ranging from 0 vol % to 60 vol %, were produced by compression molding at 370°C. In all composites produced, regardless of the initial Ti content, Ti particles were well distributed in the PEEK matrix. Addition of Ti led to a significant increase in mechanical properties of PEEK. Specifically, an increase in Ti content enhanced compressive strength and stiffness, while preserving ductile fracture behavior. In addition, the use of Ti for reinforcement of PEEK provided the composites with improved in vitro biocompatibility in terms of the attachment, proliferation, and differentiation of MC3T3-E1 cells. © 2015 Wiley Periodicals, Inc.

  8. Investigation on polyetheretherketone composite for long term storage of nuclear waste

    NASA Astrophysics Data System (ADS)

    Ajeesh, G.; Bhowmik, Shantanu; Sivakumar, Venugopal; Varshney, Lalit; Kumar, Virendra; Abraham, Mathew

    2015-12-01

    This investigation highlights the effect of radiation, chemical and thermal environments on mechanical and thermal properties of Polyetheretherketone (PEEK) composites, which could prove to be an alternative material for long term storage of nuclear wastes. The tests are conducted on specimens made from PEEK and PEEK reinforced with carbon short fiber. The specimens are subjected to radiation doses, equivalent to the cumulative dosage for 500 years followed by exposure under highly corrosive and thermal environments. Studies under optical microscopy reveal that the dispersion of carbon short fiber in the PEEK Composites is significantly uniform. Differential scanning calorimeter (DSC) and thermo gravimetric analysis (TGA) indicates that there are no significant changes in thermal properties of PEEK composite when exposed to aggressive environments. It is further observed that there are no significant changes in mechanical properties of the composite after exposure to radiation and thermo-chemical environment.

  9. Bioactivity and Osseointegration of PEEK Are Inferior to Those of Titanium: A Systematic Review.

    PubMed

    Najeeb, Shariq; Bds, Zohaib Khurshid; Bds, Sana Zohaib; Bds, Muhammad Sohail Zafar

    2016-12-01

    Polyetheretherketone (PEEK) has been suggested as an alternative to replace titanium as a dental implant material. However, PEEK's bioactivity and osseointegration are debatable. This review has systematically analyzed studies that have compared PEEK (or PEEK-based) implants with titanium implants so that its feasibility as a possible replacement for titanium can be determined. The focused question was: "Are the bioactivity and osseointegration of PEEK implants comparable to or better than titanium implants?" Using the key words "dental implant," "implant," "polyetheretherketone," "PEEK," and "titanium" in various combinations, the following databases were searched electronically: PubMED/MEDLINE, Embase, Google Scholar, ISI Web of Knowledge, and Cochrane Database. 5 in vitro and 4 animal studies were included in the review. In 4 out of 5 in vitro studies, titanium exhibited more cellular proliferation, angiogenesis, osteoblast maturation, and osteogenesis compared to PEEK; one in vitro study observed comparable outcomes regardless of the implant material. In all animal studies, uncoated and coated titanium exhibited a more osteogenic behavior than did uncoated PEEK, while comparable bone-implant contact was observed in HA-coated PEEK and coated titanium implants. Unmodified PEEK is less osseoconductive and bioactive than titanium. Furthermore, the majority of studies had multiple sources of bias; hence, in its unmodified form, PEEK is unsuitable to be used as dental implant. Significantly more research and long-term trials must focus on improving the bioactivity of PEEK before it can be used as dental implant. More comparative animal and clinical studies are warranted to ascertain the potential of PEEK as a viable alternative to titanium.

  10. Preparation, characterization, and in vitro osteoblast functions of a nano-hydroxyapatite/polyetheretherketone biocomposite as orthopedic implant material

    PubMed Central

    Ma, Rui; Tang, Songchao; Tan, Honglue; Lin, Wentao; Wang, Yugang; Wei, Jie; Zhao, Liming; Tang, Tingting

    2014-01-01

    A bioactive composite was prepared by incorporating 40 wt% nano-hydroxyapatite (nHA) into polyetheretherketone (PEEK) through a process of compounding, injection, and molding. The mechanical and surface properties of the nHA/PEEK composite were characterized, and the in vitro osteoblast functions in the composite were investigated. The mechanical properties (elastic modulus and compressive strength) of the nHA/PEEK composite increased significantly, while the tensile strength decreased slightly as compared with PEEK. Further, the addition of nHA into PEEK increased the surface roughness and hydrophilicity of the nHA/PEEK composite. In cell tests, compared with PEEK and ultra-high-molecular-weight polyethylene, it was found that the nHA/PEEK composite could promote the functions of MC3T3-E1 cells, including cell attachment, spreading, proliferation, alkaline phosphatase activity, calcium nodule formation, and expression of osteogenic differentiation-related genes. Incorporation of nHA into PEEK greatly improved the bioperformance of PEEK. The nHA/PEEK composite might be a promising orthopedic implant material. PMID:25170265

  11. Evaluation of fatigue strength of plain and notched specimens of short carbon-fiber reinforced polyetheretherketone in comparison with polyetheretherketone

    NASA Astrophysics Data System (ADS)

    Nisitani, H.; Noguchi, H.; Kim, Y.-H.

    1992-11-01

    Rotating-bending fatigue tests of short carbon-fiber reinforced polyetheretherketone (CFRPEEK) and polyetheretherketone (PEEK) were carried out to investigate the fatigue characteristics of plain and notched specimens at room temperature. The fatigue mechanisms in the matrix and composite were clarified through successive surface observations using the replica method. The results were discussed using linear notch mechanics. In the plain specimen of PEEK, fracture always occurs from defects and the fatigue crack initiation is of the point-initiation type. Furthermore, the fatigue crack growth rate is very high and the fatigue strength is very sensitive to a notch. The fatigue strength of the composite is much more insensitive to a notch than that of PEEK. In general the fatigue crack initiates from near the fiber end, and propagates to the circumferential direction after it grows to some extent along the fiber. The fatigue strength of an arbitrary notched specimen of these two materials will be estimated from the present results rearranged based on 'linear notch mechanics'.

  12. Tuning Surface Chemistry of Polyetheretherketone by Gold Coating and Plasma Treatment.

    PubMed

    Novotná, Zdeňka; Rimpelová, Silvie; Juřík, Petr; Veselý, Martin; Kolská, Zdeňka; Hubáček, Tomáš; Borovec, Jakub; Švorčík, Václav

    2017-12-01

    Polyetheretherketone (PEEK) has good chemical and biomechanical properties that are excellent for biomedical applications. However, PEEK exhibits hydrophobic and other surface characteristics which cause limited cell adhesion. We have investigated the potential of Ar plasma treatment for the formation of a nanostructured PEEK surface in order to enhance cell adhesion. The specific aim of this study was to reveal the effect of the interface of plasma-treated and gold-coated PEEK matrices on adhesion and spreading of mouse embryonic fibroblasts. The surface characteristics (polarity, surface chemistry, and structure) before and after treatment were evaluated by various experimental techniques (gravimetry, goniometry, X-ray photoelectron spectroscopy (XPS), and electrokinetic analysis). Further, atomic force microscopy (AFM) was employed to examine PEEK surface morphology and roughness. The biological response of cells towards nanostructured PEEK was evaluated in terms of cell adhesion, spreading, and proliferation. Detailed cell morphology was evaluated by scanning electron microscopy (SEM). Compared to plasma treatment, gold coating improved PEEK wettability. The XPS method showed a decrease in the carbon concentration with increasing time of plasma treatment. Cell adhesion determined on the interface between plasma-treated and gold-coated PEEK matrices was directly proportional to the thickness of a gold layer on a sample. Our results suggest that plasma treatment in a combination with gold coating could be used in biomedical applications requiring enhanced cell adhesion.

  13. Tuning Surface Chemistry of Polyetheretherketone by Gold Coating and Plasma Treatment

    NASA Astrophysics Data System (ADS)

    Novotná, Zdeňka; Rimpelová, Silvie; Juřík, Petr; Veselý, Martin; Kolská, Zdeňka; Hubáček, Tomáš; Borovec, Jakub; Švorčík, Václav

    2017-06-01

    Polyetheretherketone (PEEK) has good chemical and biomechanical properties that are excellent for biomedical applications. However, PEEK exhibits hydrophobic and other surface characteristics which cause limited cell adhesion. We have investigated the potential of Ar plasma treatment for the formation of a nanostructured PEEK surface in order to enhance cell adhesion. The specific aim of this study was to reveal the effect of the interface of plasma-treated and gold-coated PEEK matrices on adhesion and spreading of mouse embryonic fibroblasts. The surface characteristics (polarity, surface chemistry, and structure) before and after treatment were evaluated by various experimental techniques (gravimetry, goniometry, X-ray photoelectron spectroscopy (XPS), and electrokinetic analysis). Further, atomic force microscopy (AFM) was employed to examine PEEK surface morphology and roughness. The biological response of cells towards nanostructured PEEK was evaluated in terms of cell adhesion, spreading, and proliferation. Detailed cell morphology was evaluated by scanning electron microscopy (SEM). Compared to plasma treatment, gold coating improved PEEK wettability. The XPS method showed a decrease in the carbon concentration with increasing time of plasma treatment. Cell adhesion determined on the interface between plasma-treated and gold-coated PEEK matrices was directly proportional to the thickness of a gold layer on a sample. Our results suggest that plasma treatment in a combination with gold coating could be used in biomedical applications requiring enhanced cell adhesion.

  14. Characterization and Bioactivity Evaluation of (Polyetheretherketone/Polyglycolicacid)-Hydroyapatite Scaffolds for Tissue Regeneration

    PubMed Central

    Shuai, Cijun; Shuai, Chenying; Wu, Ping; Yuan, Fulai; Feng, Pei; Yang, Youwen; Guo, Wang; Fan, Xiaohan; Su, Ting; Peng, Shuping; Gao, Chengde

    2016-01-01

    Bioactivity and biocompatibility are crucial for tissue engineering scaffolds. In this study, hydroxyapatite (HAP) was incorporated into polyetheretherketone/polyglycolicacid (PEEK/PGA) hybrid to improve its biological properties, and the composite scaffolds were developed via selective laser sintering (SLS). The effects of HAP on physical and chemical properties of the composite scaffolds were investigated. The results demonstrated that HAP particles were distributed evenly in PEEK/PGA matrix when its content was no more than 10 wt %. Furthermore, the apatite-forming ability became better with increasing HAP content after immersing in simulated body fluid (SBF). Meanwhile, the composite scaffolds presented a greater degree of cell attachment and proliferation than PEEK/PGA scaffolds. These results highlighted the potential of (PEEK/PGA)-HAP scaffolds for tissue regeneration. PMID:28774058

  15. A combination of CO2 laser and plasma surface modification of poly(etheretherketone) to enhance osteoblast response

    NASA Astrophysics Data System (ADS)

    Zheng, Yanyan; Xiong, Chengdong; Wang, Zhecun; Li, Xiaoyu; Zhang, Lifang

    2015-07-01

    Poly(etheretherketone) (PEEK) is a rigid semicrystalline polymer that combines excellent mechanical properties, broad chemical resistance and bone-like stiffness and is widely used in biomedical fields. However, the bio-inert surface of PEEK tends to hinder its biomedical applications when direct osteointegration between the implants and the host tissue is desired. In this work, we demonstrate a dual modification method, which combines the laser and plasma surface treatment to combine advantages of both chemical states and microstructures for osteoblasts responses. While the plasma treatment introduces surface carboxyl groups (sbnd COOH) onto PEEK surface, the laser treatment constructs microstructures over the PEEK surface. Our results indicated that sbnd COOH as well as microgrooves containing micropores or microcraters structure are constructed on PEEK surface and plasma treatment has no apparent effect on the morphology of microstructures produced by laser micromachining. Unexpectedly, the superior mechanical properties of PEEK were maintained irrespective of the treatment used. Compared to native PEEK and single treated PEEK, dual modified PEEK is more favorable for pre-osteoblasts (MC3T3-E1) adhesion, spreading and proliferation. Moreover, cell pseudopodia protrude into the micropores or microcraters, in favor of forming firmer bone-implant integration. Our study illustrates enhanced osteoblasts responses to dual treated PEEK surface, which gives beneficial information of its potential use in orthopedic or dental implants.

  16. Fabrication and characterization of modified-hydroxyapatite/polyetheretherketone coating materials

    NASA Astrophysics Data System (ADS)

    Ma, Rui; Fang, Lin; Luo, Zhongkuan; Zheng, Ruisheng; Song, Shenhua; Weng, Luqian; Lei, JinPing

    2014-09-01

    45 wt%-Hydroxyaptite/polyetheretherketone (HA/PEEK) coating materials modified by silane coupling agent (KH560) on PEEK substrate were successfully fabricated by solution casting method and characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and tensile testing. The modified HA fillers were obtained to be uniformly distributed in the HA/PEEK coating, which has better properties of tensile strength and fracture toughness than those of the unmodified specimen. A good bonding between the composite coating and the PEEK substrate was achieved by solution casting method, resulting in integral-fracture without falling apart or delaminating during tensile loading. The modified specimens dipped into simulated body fluid (SBF) were characterized by SEM, XRD and FTIR, indicating that the bioactivity of the dipped materials was demonstrated more apparent with extending the dipping time. Therefore, the coating materials may become the substitutes for the hard tissues of the human body in the future, which could realize the balance between the mechanical properties and the bioactivity by modifying the structural design of the coating.

  17. Effects of Different pH-Values on the Nanomechanical Surface Properties of PEEK and CFR-PEEK Compared to Dental Resin-Based Materials

    PubMed Central

    Gao, Shuai; Gao, Shanshan; Xu, Baohua; Yu, Haiyang

    2015-01-01

    The study determines the stability and durability of polyetheretherketone (PEEK) and a carbon fiber-reinforced PEEK (CFR-PEEK) with 30% short carbon fibers, a dental composite based on Bis-GMA and polymethylmethacrylate (PMMA) under the influence of different pH-values of the oral environment in vitro. Nanomechanical properties were investigated by nanoindentation and nanoscratch tests before and after incubation of the specimens at 37 °C for 30 days in artificial saliva with pH-values of 3, 7 and 10, respectively. Nanoindentation and nanoscratching tests were performed using the Hysitron TI950 TriboIndenter to evaluate the reduced elastic moduli, nanohardness, viscoelasticity, friction coefficient and residual scratch profiles. After treatment, the nanomechanical properties of unfilled PEEK did not change. The reduced elastic moduli and nanohardness of the carbon fiber-reinforced PEEK increased significantly. The reduced elastic moduli and nanohardness of CHARISMA decreased. The plasticity of all materials except that of the unfilled PEEK increased. This indicates that different pH-values of the artificial saliva solutions had no obvious influences on the nanomechanical properties of the PEEK matrix. Therefore, the aging resistance of the unfilled PEEK was higher than those of other materials. It can be deduced that the PEEK matrix without filler was more stable than with filler in the nanoscale. PMID:28793469

  18. Preparation and characterization of bio-composite PEEK/nHA

    NASA Astrophysics Data System (ADS)

    Jin, Y. S.; Bian, C. C.; Zhang, Z. Q.; Zhao, Y.; Yang, L.

    2017-01-01

    PEEK/nHA composite material, with excellent mechanical property as polyetheretherketone (PEEK) and biological activity as hydroxyapatite (HA), has attracted wide attention of medical experts and materials science experts. The addition of hydroxyapatite was the decisive factor for biological activity in PEEK/nHA composite. In this paper, acicular nanohydroxyapatite was prepared by chemical precipitation method with Ca(NO3)2, (NH4)2HPO4 as raw material; PEEK/nHA composite was prepared by solution blending and vacuum sintering method. The composite was characterized with FT-IR, XRD, DSC, TG and mechanical property test. Results showed that the composite has good thermal stability and compressive property when the mass ratio of PEEK to nHA is 10:3; and high nHA content can improve the biological activity of the composite, which can meet the basic requirements for bone tissue engineering scaffold.

  19. Neutral atom beam technique enhances bioactivity of PEEK

    NASA Astrophysics Data System (ADS)

    Khoury, Joseph; Kirkpatrick, Sean R.; Maxwell, Melissa; Cherian, Raymond E.; Kirkpatrick, Allen; Svrluga, Richard C.

    2013-07-01

    Polyetheretherketone (PEEK) is currently gaining popularity in orthopedic and spinal applications but has potential drawbacks in use. PEEK is biocompatible, similar in elasticity to bone, and radiolucent; however, it has been shown to be inert and does not integrate well with bone. Recent efforts have focused on increasing the bioactivity of PEEK by modifying the surface to improve the bone-implant interface. We have employed a novel Accelerated Neutral Atom Beam technique (ANAB) to enhance the bioactivity of PEEK. ANAB employs an intense beam of cluster-like packets of accelerated unbonded neutral argon (Ar) gas atoms. These beams are created by first producing a highly energetic Gas Cluster Ion Beam (GCIB) comprised of van der Waals bonded Ar atoms, then transferring energy to the clusters so as to cause release of most of the interatomic bonds, and finally deflecting away the remaining electrically charged cluster cores of still bonded atoms. We identified that ANAB treatment of PEEK results in nanometer scale surface modifications as well as increased surface hydrophilicity. Human osteoblasts seeded onto the surface of ANAB-treated PEEK exhibited enhanced growth as compared to control PEEK as evidenced by cell proliferation assays and microscopy. This increase in bioactivity resulted in cell proliferation levels comparable to native titanium. An in vivo study using a rat calvarial critical size defect model revealed enhanced osseointegration where bone tissue formation was evident only on the ANAB treated PEEK. Taken together, these data suggest that ANAB treatment of PEEK has the potential to enhance its bioactivity, resulting in bone formation and significantly decreasing osseointegration time of orthopedic and spinal implants.

  20. Bone-like apatite coating on functionalized poly(etheretherketone) surface via tailored silanization layers technique.

    PubMed

    Zheng, Yanyan; Xiong, Chengdong; Zhang, Shenglan; Li, Xiaoyu; Zhang, Lifang

    2015-10-01

    Poly(etheretherketone) (PEEK) is a rigid semi-crystalline polymer with outstanding mechanical properties, bone-like stiffness and suitable biocompatibility that has attracted much interest as a biomaterial for orthopedic and dental implants. However, the bio-inert surface of PEEK limits its biomedical applications when direct osteointegration between the implants and the host tissue is desired. In this work, -PO4H2, -COOH and -OH groups were introduced on the PEEK surface by further chemical treatments of the vinyl-terminated silanization layers formed on the hydroxylation-pretreated PEEK surface. Both the surface-functionalized and pristine specimens were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and water contact angle measurements. When placed in 1.5 strength simulated body fluid (SBF) solution, apatite was observed to form uniformly on the functionalized PEEK surface and firmly attach to the substrate. The characterized results demonstrated that the coating was constituted by poorly crystallized bone-like apatite and the effect of surface functional groups on coating formation was also discussed in detail. In addition, in vitro biocompatibility of PEEK, in terms of pre-osteoblast cell (MC3T3-E1) attachment, spreading and proliferation, was remarkably enhanced by the bone-like apatite coating. Thus, this study provides a method to enhance the bioactivity of PEEK and expand its applications in orthopedic and dental implants.

  1. [Research on the extracorporeal cytocompatibility of a composite of HA, carbon fiber and polyetheretherket-one].

    PubMed

    Liu, Xueyong; Deng, Chunbo; Liu, Jiquan; Li, Jianjun; Sui, Guoxin

    2011-12-01

    The present research was to study the biocompatibility of a composite of hydroxyapatite (HA), carbon fiber (CF) and polyetheretherket-one (PEEK) by co-culturing with the osteoblasts in vitro. Cell relative growth (RGR) was used as a quantitative assessment for cytotoxicity of the biomaterials by CCK-8. The proliferation index of the co-cultured cells and ALP activity was measured to study the effect of PEEK-HA-CF composites. Morphological properties of the osteoblast cells in vitro were observed by scanning electro-microscopy (SEM). The PEEK-HA-CF materials have no cytotoxicity to osteoblasts. The proliferation index of PEEK-HA-CF was higher than that of Ti alloy group, but these was no significant difference compared to that of control group. The ALP activity was the highest on PEEK-HA-CF composites surface after 7 days. The osteoblast cells co-cultured with the PEEK-HA-CF composite were adhered well to the biomaterial as observed under the SEM. The results suggested that the PEEK-HA-CF composites had good biocompatibility in vitro and might be a novel orthopedic implanted material.

  2. In Vivo Osseointegration Performance of Titanium Dioxide Coating Modified Polyetheretherketone Using Arc Ion Plating for Spinal Implant Application

    PubMed Central

    Tsou, Hsi-Kai; Chi, Meng-Hui; Hung, Yi-Wen; Chung, Chi-Jen; He, Ju-Liang

    2015-01-01

    Polyetheretherketone (PEEK), which has biomechanical performance similar to that of human cancellous bone, is used widely as a spinal implant material. However, its bioinertness and hydrophobic surface properties result in poor osseointegration. This study applies a novel modification method, arc ion plating (AIP), that produces a highly osteoblast compatible titanium dioxide (TiO2) coatings on a PEEK substrate. This PEEK with TiO2 coating (TiO2/PEEK) was implanted into the femurs of New Zealand white male rabbits to evaluate its in vivo performance by the push-out test and histological observation. Analytical results show that AIP can prepare TiO2 coatings on bullet-shaped PEEK substrates as implant materials. After prolonged implantation in rabbits, no signs of inflammation existed. Newly regenerated bone formed more prominently with the TiO2/PEEK implant by histological observation. The shear strength of the bone/implant interface increases as implantation period increases. Most importantly, bone bonding performance of the TiO2/PEEK implant was superior to that of bare PEEK. The rutile-TiO2 coatings achieved better osseointegration than the anatase-TiO2 coatings. Therefore, AIP-TiO2 can serve as a novel surface modification method on PEEK for spinal interbody fusion cages. PMID:26504800

  3. Osteoconductive hydroxyapatite coated PEEK for spinal fusion surgery

    NASA Astrophysics Data System (ADS)

    Hahn, Byung-Dong; Park, Dong-Soo; Choi, Jong-Jin; Ryu, Jungho; Yoon, Woon-Ha; Choi, Joon-Hwan; Kim, Jong-Woo; Ahn, Cheol-Woo; Kim, Hyoun-Ee; Yoon, Byung-Ho; Jung, In-Kwon

    2013-10-01

    Polyetheretherketone (PEEK) has attracted much interest as biomaterial for interbody fusion cages due to its similar stiffness to bone and good radio-transparency for post-op visualization. Hydroxyapatite (HA) coating stimulates bone growth to the medical implant. The objective of this work is to make an implant consisting of biocompatible PEEK with an osteoconductive HA surface for spinal or orthopedic applications. Highly dense and well-adhered HA coating was developed on medical-grade PEEK using aerosol deposition (AD) without thermal degradation of the PEEK. The HA coating had a dense microstructure with no cracks or pores, and showed good adhesion to PEEK at adhesion strengths above 14.3 MPa. The crystallinity of the HA coating was remarkably enhanced by hydrothermal annealing as post-deposition heat-treatment. In addition, in vitro and in vivo biocompatibility of PEEK, in terms of cell adhesion morphology, cell proliferation, differentiation, and bone-to-implant contact ratio, were remarkably enhanced by the HA coating through AD.

  4. High strength, surface porous polyether-ether-ketone for load-bearing orthopaedic implants

    PubMed Central

    Evans, Nathan T.; Torstrick, F. Brennan; Lee, Christopher S.D.; Dupont, Kenneth M.; Safranski, David L.; Chang, W. Allen; Macedo, Annie E.; Lin, Angela; Boothby, Jennifer M.; Whittingslow, Daniel C.; Carson, Robert A.; Guldberg, Robert E.; Gall, Ken

    2015-01-01

    Despite its widespread clinical use in load-bearing orthopaedic implants, polyether-ether-ketone (PEEK) is often associated with poor osseointegration. In this study, a surface porous PEEK material (PEEK-SP) was created using a melt extrusion technique. The porous layer thickness was 399.6±63.3 µm and possessed a mean pore size of 279.9±31.6 µm, strut spacing of 186.8±55.5 µm, porosity of 67.3±3.1%, and interconnectivity of 99.9±0.1%. Monotonic tensile tests showed that PEEK-SP preserved 73.9% of the strength (71.06±2.17 MPa) and 73.4% of the elastic modulus (2.45±0.31 GPa) of as-received, injection molded PEEK. PEEK-SP further demonstrated a fatigue strength of 60.0 MPa at one million cycles, preserving 73.4% of the fatigue resistance of injection molded PEEK. Interfacial shear testing showed the pore layer shear strength to be 23.96±2.26 MPa. An osseointegration model in the rat revealed substantial bone formation within the pore layer at 6 and 12 weeks via µCT and histological evaluation. Ingrown bone was more closely apposed to the pore wall and fibrous tissue growth was reduced in PEEK-SP when compared to non-porous PEEK controls. These results indicate that PEEK-SP could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopaedic applications. PMID:25463499

  5. Degradation in Thermal Properties and Morphology of Polyetheretherketone-Alumina Composites Exposed to Gamma Radiation

    NASA Astrophysics Data System (ADS)

    Lawrence, Falix; Mishra, Satyabrata; Mallika, C.; Kamachi Mudali, U.; Natarajan, R.; Ponraju, D.; Seshadri, S. K.; Sampath Kumar, T. S.

    2012-07-01

    Sheets of polyetheretherketone (PEEK) and PEEK-alumina composites with micron-sized alumina powder with 5, 10, 15, 20, and 25% by weight were fabricated, irradiated with gamma rays up to 10 MGy and the degradation in their thermal properties and morphology were evaluated. The radicals generated during irradiation get stabilized by chain scission and crosslinking. Chain scission is predominant on the surface and crosslinking is predominant in the bulk of the samples. Owing to radiation damage, the glass transition temperature, T g increased for pure PEEK from 136 to 140.5 °C, whereas the shift in T g for the composites decreased with increase in alumina content and for PEEK-25% alumina, the change in T g was insignificant, as alumina acts as an excitation energy sink and reduces the crosslinking density, which in turn decreased the shift in T g towards higher temperature. Similarly, the melting temperature, T m and enthalpy of melting, Δ H m of PEEK and PEEK-alumina composites decreased on account of radiation owing to the restriction of chain mobility and disordering of structures caused by crosslinks. The decrease in T m and Δ H m was more pronounced in pure PEEK and the extent of decrease in T m and Δ H m was less for composites. SEM images revealed the formation of micro-cracks and micro-pores in PEEK due to radiation. The SEM image of irradiated PEEK-alumina (25%) composite showed negligible micro-cracks and micro-pores, because of the reinforcing effect of high alumina content in the PEEK matrix which helps in reducing the degradation in the properties of the polymer. Though alumina reduces the degradation of the polymer matrix during irradiation, an optimum level of ceramic fillers only have to be loaded to the polymer to avoid the reduction in toughness.

  6. Two-level contiguous cervical disc disease treated with peek cages packed with demineralized bone matrix: results of 3-year follow-up

    PubMed Central

    Topuz, Kıvanç; Çolak, Ahmet; Şimşek, Hakan; Kutlay, Murat; Demircan, Mehmet Nusret; Velioğlu, Murat

    2009-01-01

    Interbody cages are widely used instruments for cervical fusion operations. Long-term follow-up studies are needed to clarify if these devices are dependable. In this prospective study, 79 patients (42 women and 37 men) with a mean age of 51 years operated between January 2000 and December 2005 for treatment of degenerative cervical disc disease and spondylosis associated with radiculopathy or myelopathy were evaluated. Patients underwent two-level contiguous anterior cervical discectomy and fusion operations with standard anterior Smith–Robinson approach. To achieve fusion PEEK cages packed with demineralized bone matrix mixed with autologous blood were used. Clinical outcome was evaluated with Odom’s criteria and results were evaluated as ‘excellent’, ‘good’, ‘fair’ and ‘poor’. Spinal curves, mobility and fusion status were assessed with anterior–posterior and lateral (neutral, flexion and extension) radiographs obtained before surgery and at 3, 12, 24 and 36 months postoperatively. The Ishihara curvature index (ICI) was used for spinal curve evaluation. Lateral dynamic (flexion and extension) radiographs at postoperative 12th month revealed the fusion status classified as 1A, 1B, 2A and 2B. The radiological outcomes were classified as ‘non-fusion’ when 2B healing was observed, and as ‘fusion’ when 1A, 1B or 2A healing was observed at the levels subjected to surgery. According to Odom’s criteria, clinical outcomes were classified as ‘excellent’ or ‘good’ in 69 patients (success rate: 87.3%). Eight patients were graded as ‘fair’ and two as ‘poor’. Preoperative mean ICI was 10.4 ± 3.72 and postoperative mean ICI was 10.1 ± 3.14. The difference was statistically insignificant (P > 0.05); therefore, preoperative lordosis was said to be preserved at final follow-up. Final fusion rate (Types 1A, 1B, and 2A) was 91.7% (145/158 levels). Radiological imaging showed no cage failure or dislodgement and reoperation

  7. Wear of PEEK-OPTIMA® and PEEK-OPTIMA®-Wear Performance articulating against highly cross-linked polyethylene.

    PubMed

    East, Rebecca H; Briscoe, Adam; Unsworth, Anthony

    2015-03-01

    The idea of all polymer artificial joints, particularly for the knee and finger, has been raised several times in the past 20 years. This is partly because of weight but also to reduce stress shielding in the bone when stiffer materials such as metals or ceramics are used. With this in mind, pin-on-plate studies of various polyetheretherketone preparations against highly cross-linked polyethylene were conducted to investigate the possibility of using such a combination in the design of a new generation of artificial joints. PEEK-OPTIMA(®) (no fibre) against highly cross-linked polyethylene gave very low wear factors of 0.0384 × 10(-6) mm(3)/N m for the polyetheretherketone pins and -0.025 × 10(-6) mm(3)/N m for the highly cross-linked polyethylene plates. The carbon-fibre-reinforced polyetheretherketone (PEEK-OPTIMA(®)-Wear Performance) also produced very low wear rates in the polyetheretherketone pins but produced very high wear in the highly cross-linked polyethylene, as might have been predicted since the carbon fibres are quite abrasive. When the fibres were predominantly tangential to the sliding plane, the mean wear factor was 0.052 × 10(-6) mm(3)/N m for the pins and 49.3 × 10(-6) mm(3)/N m for the highly cross-linked polyethylene plates; a half of that when the fibres ran axially in the pins (0.138 × 10(-6) mm(3)/N m for the pins and 97.5 × 10(-6) mm/ N m for the cross-linked polyethylene plates). PEEK-OPTIMA(®) against highly cross-linked polyethylene merits further investigation.

  8. Surface modification of nanodiamond and its incorporation in nanodiamond/peek nanocomposites

    NASA Astrophysics Data System (ADS)

    Wahab, Zahidul

    The continued miniaturization of electronic device components requires new lightweight polymers with high thermal stability, high thermal conductivity, low electrical conductivity, and low dielectric constant. Composites of nanodiamond (ND) and poly-ether-ether-ketone (PEEK) are candidates for these applications due their unique combination of properties. The objectives of this research are to explore new routes for surface functionalization of nanodiamond (ND), develop methods for maximizing dispersion of ND as a nano-scale filler in PEEK, and characterize the effect of dispersed ND on the mechanical, thermal and dielectric properties of ND/PEEK composites. Initial attempts to disperse different kinds of commercially available, as-received ND in PEEK were yielded low quality composites due to ND agglomeration and low thermal stability. Thus we began to explore chemical grafting of phenylphosphonate (PPA) onto oxidized ND (OND) and carboxylated ND (CND), hypothesizing that the phenyl functional group would render the NDs more compatible with aromatic PEEK. Detailed characterization results, including 31P NMR, FTIR, and XPS, indicate successful grafting, resulting in arylation of ND, increased ND thermal stability, and better compatibility with organic solvents. Sonication during the grafting promotes more complete exposure of the ND surface to PPA grafting, resulting in even better ND dispersion in organic solvents. PPA-modified OND and CND were then melt-blended with PEEK to produce ND/PEEK composites. Surface tomography results suggest that all PPA-modified NDs were adequately dispersed in PEEK, with OND showing better dispersion due to its higher PPA graft density. The presence of PPA-modified ND has minor impact on PEEK crystallinity based on XRD and DSC data. Tensile testing and DMA results suggest that ND/PEEK composites generally retain the mechanical properties of PEEK with some sacrifice of ductility. TGA data indicate that all ND/PEEK composites have

  9. Fatigue limits of different PEEK materials for dental implants.

    PubMed

    Schwitalla, Andreas Dominik; Zimmermann, Tycho; Spintig, Tobias; Kallage, Ilona; Müller, Wolf-Dieter

    2016-12-23

    The increasing use of PEEK (poly-ether-ether-ketone) as a substitute for metal implant components has led to the suggestion that it could also be used as an alternative to titanium in the field of dental implants. A major requirement for dental implant materials is their resistance to cyclic loading due to mastication. A special fatigue test was designed to evaluate the elastic behavior and long-term form stability of cylindrically shaped PEEK specimens of 4, 5 and 6mm in diameter, using 11 different PEEK materials of various grades: unfilled, filled with titanium dioxide or barium sulfate powder, reinforced with short carbon fibers or short glass fibers, and reinforced with continuous carbon fibers. The samples were exposed to cyclic loads of up to 2000N. The elastic limits ranged between 46.57±6.44MPa for short carbon fiber reinforced specimens of 6mm diameter and 107.62±8.23MPa for samples of a different short carbon fiber reinforced PEEK compound of 4mm diameter. The elastic limits of the two PEEK grades containing continuous carbon fibers could not be observed because they exceeded the limits of the test specification. The elastic moduli ranged between 2.06±0.18GPa for barium sulfate powder filled PEEK-specimens of 6 mm diameter and 57.53±14.3GPa for continuous carbon fibers reinforced PEEK-specimens of 4 mm diameter. In terms of the elastic limit all the PEEK materials in consideration were able to resist the pressure caused by maximum masticatory forces.

  10. Self-tapping ability of carbon fibre reinforced polyetheretherketone suture anchors.

    PubMed

    Feerick, Emer M; Wilson, Joanne; Jarman-Smith, Marcus; Ó'Brádaigh, Conchur M; McGarry, J Patrick

    2014-10-01

    An experimental and computational investigation of the self-tapping ability of carbon fibre reinforced polyetheretherketone (CFR-PEEK) has been conducted. Six CFR-PEEK suture anchor designs were investigated using PEEK-OPTIMA® Reinforced, a medical grade of CFR-PEEK. Experimental tests were conducted to investigate the maximum axial force and torque required for self-taping insertion of each anchor design. Additional experimental tests were conducted for some anchor designs using pilot holes. Computational simulations were conducted to determine the maximum stress in each anchor design at various stages of insertion. Simulations also were performed to investigate the effect of wall thickness in the anchor head. The maximum axial force required to insert a self-tapping CFR-PEEK suture anchor did not exceed 150 N for any anchor design. The maximum torque required to insert a self-tapping CFR-PEEK suture anchor did not exceed 0.8 Nm. Computational simulations reveal significant stress concentrations in the region of the anchor tip, demonstrating that a re-design of the tip geometry should be performed to avoid fracture during self-tapping, as observed in the experimental component of this study. This study demonstrates the ability of PEEK-OPTIMA Reinforced suture anchors to self-tap polyurethane foam bone analogue. This provides motivation to further investigate the self-tapping ability of CFR-PEEK suture anchors in animal/cadaveric bone. An optimised design for CFR-PEEK suture anchors offers the advantages of radiolucency, and mechanical properties similar to bone with the ability to self-tap. This may have positive implications for reducing surgery times and the associated costs with the procedure.

  11. Locking screw-plate interface stability in carbon-fibre reinforced polyetheretherketone proximal humerus plates.

    PubMed

    Hak, David J; Fader, Ryan; Baldini, Todd; Chadayammuri, Vivek B S

    2017-07-13

    Carbon-fibre reinforced polyetheretherketone (CFR-PEEK) plates have recently been introduced for proximal humerus fracture treatment. The purpose of this study was to compare the locking screw-plate interface stability in CFR-PEEK versus stainless steel (SS) proximal humerus plates. Locking screw mechanical stability was evaluated independently in proximal and shaft plate holes. Stiffness and load to failure were tested for three conditions: (1) on-axis locking screw insertion in CFR-PEEK versus SS plates, (2) on-axis locking screw insertion, removal, and reinsertion in CFR-PEEK plates, and (3) 10-degree off-axis locking screw insertion in CFR-PEEK plates. Cantilever bending at a rate of 1 mm/minute was produced by an Instron machine and load-displacement data recorded. Shaft locking screw load to failure was significantly greater in CFR-PEEK plates compared to SS plates (746.4 ± 89.7 N versus 596.5 ± 32.6 N, p < 0.001). The stiffness and load to failure of shaft locking screws was significantly decreased when inserted 10 degrees off-axis compared to on-axis in CFR-PEEK plates (p < 0.001). Stiffness and load to failure did not vary significantly following screw reinsertion in CFR-PEEK plates. The mechanical stability of locking screws in CFR-PEEK plates is comparable or superior to locking screws in SS plates.

  12. Biocompatibility of nano-hydroxyapatite/polyetheretherketone composite materials with osteoblasts cultured in vitro

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Huang, Feijuan; Wu, Zhengzhi; Ma, Rui

    2017-04-01

    The biocompatibility of the Sprague Dawley (SD) rat osteoblasts, which were cultured on the surfaces of nano-hydroxyapatite/polyetheretherketone (n-HA/PEEK) composites were investigated in this work. The osteoblasts of 24- hour old SD rats were cultured and identified by modified enzymatic digestion in vitro. The morphology and proliferation of cells were observed in CCK-8 regent staining, inverted microscopes, and by scanning electron microscopy (SEM) respectively. The results show that n-HA/PEEK composites have good biocompatibility with SD osteoblasts and that they can promote the growth of the cells that were cultured on the surfaces of the composites. The content of HA in n- HA/PEEK composites plays an important role in cell proliferation.

  13. Graphene oxide as an interface phase between polyetheretherketone and hydroxyapatite for tissue engineering scaffolds

    PubMed Central

    Peng, Shuping; Feng, Pei; Wu, Ping; Huang, Wei; Yang, Youwen; Guo, Wang; Gao, Chengde; Shuai, Cijun

    2017-01-01

    The poor bonding strength between biopolymer and bioceramic has remained an unsolved issue. In this study, graphene oxide (GO) was introduced as an interface phase to improve the interfacial bonding between polyetheretherketone (PEEK) and hydroxyapatite (HAP) for tissue engineering scaffolds. On the one hand, the conjugated structure of GO could form strong π-π stacking interaction with the benzene rings in PEEK. On the other hand, GO with a negatively charge resulting from oxygen functional groups could adsorb the positively charged calcium atoms (C sites) of HAP. Consequently, the dispersibility and compatibility of HAP in the PEEK matrix increased with increasing GO content up to 1 wt%. At this time, the compressive strength and modulus of scaffolds increased by 79.45% and 42.07%, respectively. Furthermore, the PEEK-HAP with GO (PEEK-HAP/GO) scaffolds possessed the ability to induce formation of bone-like apatite. And they could support cellular adhesion, proliferation as well as osteogenic differentiation. More importantly, in vivo bone defect repair experiments showed that new bone formed throughout the scaffolds at 60 days after implantation. All these results suggested that the PEEK-HAP/GO scaffolds have a promising potential for bone tissue engineering application. PMID:28425470

  14. Bacterial adhesion to orthopaedic implant materials and a novel oxygen plasma modified PEEK surface.

    PubMed

    Rochford, E T J; Poulsson, A H C; Salavarrieta Varela, J; Lezuo, P; Richards, R G; Moriarty, T F

    2014-01-01

    Despite extensive use of polyetheretherketone (PEEK) in biomedical applications, information about bacterial adhesion to this biomaterial is limited. This study investigated Staphylococcus aureus and Staphylococcus epidermidis adhesion to injection moulded and machined PEEK OPTIMA(®) using a custom-built adhesion chamber with medical grade titanium and Thermanox for comparison. Additionally, bacterial adhesion to a novel oxygen plasma modified PEEK was also investigated in both a pre-operative model in physiological saline, and additionally in a post-operative model in human blood plasma. In the pre-operative model, the rougher machined PEEK had a significantly greater number of adherent bacteria compared to injection moulded PEEK. Bacterial adhesion to titanium and Thermanox was similar. Oxygen plasma surface modification of PEEK did not lead to a significant change in bacterial adhesion in the pre-operative contamination model, despite observed changes in surface characteristics. In the post-operative contamination model, S. aureus adhesion was increased from 5×10(5) CFU cm(-2) to approximately 1.3×10(7) CFU cm(-2) on the modified surfaces due to differential protein adhesion during the conditioning period. However, S. epidermidis adhesion to modified PEEK was less than to unmodified PEEK in the post-operative model. These results illustrate the importance of testing bacterial adhesion of several strains in both a pre-operative and post-operative, clinically relevant bacterial contamination model.

  15. The applicability of PEEK-based abutment screws.

    PubMed

    Schwitalla, Andreas Dominik; Abou-Emara, Mohamed; Zimmermann, Tycho; Spintig, Tobias; Beuer, Florian; Lackmann, Justus; Müller, Wolf-Dieter

    2016-10-01

    The high-performance polymer PEEK (poly-ether-ether-ketone) is more and more being used in the field of dentistry, mainly for removable and fixed prostheses. In cases of screw-retained implant-supported reconstructions of PEEK, an abutment screw made of PEEK might be advantageous over a conventional metal screw due to its similar elasticity. Also in case of abutment screw fracture, a screw of PEEK could be removed more easily. M1.6-abutment screws of four different PEEK compounds were subjected to tensile tests to set their maximum tensile strengths in relation to an equivalent stress of 186MPa, which is aused by a tightening torque of 15Ncm. Two screw types were manufactured via injection molding and contained 15% short carbon fibers (sCF-15) and 40% (sCF-40), respectively. Two screw types were manufactured via milling and contained 20% TiO2 powder (TiO2-20) and >50% parallel orientated, continuous carbon fibers (cCF-50). A conventional abutments screw of Ti6Al4V (Ti; CAMLOG(®) abutment screw, CAMLOG, Wimsheim, Germany) served as control. The maximum tensile strength was 76.08±5.50MPa for TiO2-20, 152.67±15.83MPa for sCF-15, 157.29±20.11MPa for sCF-40 and 191.69±36.33MPa for cCF-50. The maximum tensile strength of the Ti-screws amounted 1196.29±21.4MPa. The results of the TiO2-20 and the Ti screws were significantly different from the results of the other samples, respectively. For the manufacturing of PEEK abutment screws, PEEK reinforced by >50% continuous carbon fibers would be the material of choice. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Maximum insertion torque of a novel implant-abutment-interface design for PEEK dental implants.

    PubMed

    Schwitalla, Andreas Dominik; Zimmermann, Tycho; Spintig, Tobias; Abou-Emara, Mohamed; Lackmann, Justus; Müller, Wolf-Dieter; Houshmand, Alireza

    2017-09-05

    Frequent reports attest to the various advantages of tapered implant/abutment interfaces (IAIs) compared to other types of interfaces. For this reason, a conical IAI was designed as part of the development of a PEEK (polyetheretherketone)-based dental implant. This IAI is equipped with an apically displaced anti-rotation lock with minimal space requirements in the form of an internal spline. The objective of this study was the determination of the average insertion torque (IT) at failure of this design, so as to determine its suitability for immediate loading, which requires a minimum IT of 32Ncm. 10 implants each made of unfilled PEEK, carbon fiber reinforced ("CFR") PEEK (> 50vol% continuous axially parallel fibers) as well as of titanium were produced and tested in a torque test bench. The average IT values at failure of the unfilled PEEK implants were measured at 22.6 ± 0.5Ncm and were significantly higher than those of the CFR-Implants (20.2 ± 2.5Ncm). The average IT values at failure of the titanium specimens were significantly higher (92.6 ± 2.3Ncm) than those of the two PEEK variants. PEEK- and CFR-PEEK-implants in the present form cannot adequately withstand the insertion force needed to achieve primary stability for immediate loading. Nevertheless, the achievable torque resilience of the two PEEK-variants may be sufficient for a two-stage implantation procedure. To improve the torque resistance of the PEEK implant material the development of a new manufacturing procedure is necessary which reinforces the PEEK base with continuous multi-directional carbon fibers as opposed to the axially parallel fibers of the tested PEEK compound. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. [Experience with Poly Ether Ether Ketone (PEEK) cages and locking plate for anterior cervical fusion in the treatment of spine trauma without cord injury].

    PubMed

    Delépine, F; Jund, S; Schlatterer, B; de Peretti, F

    2007-12-01

    The purpose of this study was to determine whether spinal fusion using radiotransparent cages can be an appropriate treatment for traumatic injury of the cervical spine. This series included 30 patients aged 17-84 years (average 46 years) treated between October 1999 and June 2003 for traumatic injury of the cervical spine without neurological deficit or cord injury. There were two bifocal cases so that the study concerned 32 fusions. Injuries were: tear drop (n=1), serious flexion sprain (n=8), biarticular dislocation (n=4), serous hyperextension sprain (n=4), dislocation-fracture (n=1), uniarticular fracture (n=7), fracture-separation of the facet joints (n=4), post-traumatic herniation (n=3). For each injury, we measured pre and postoperatively and at last follow-up: the intersomatic angle, anterior displacement, and height of the intersomatic space at the center of the intervertebral disc. All x-rays were read twice, by two independent investigators. In the event of disagreement, the x-rays were read again by a senior surgeon and the main author of this article. Anterior fusion was achieved using a Poly Ether Ether Ketone (PEEK) (32%) and knitted carbon (68%) cage (cologne, Ostapek, Nexis) filled with cancellous bone harvested percutaneously from the iliac crest. The cage was associated with an anterior titanium plate fixation (Senegas, Euros and Orion, Medtronic). A posterior approach was associated if further stability was required (n=4 fusions). All patients were reviewed at minimum five months follow-up. Intersomatic fusion was verified on the standard x-rays (plus stress images and computed tomography at three months). Fusion was considered to be achieved if continuous bone lines crossed the graft and angle measurements remained stable, with the cage in the same position on successive examinations. One patient died from lung cancer five months after spinal fusion. All other patients survived with a mean follow-up of 24 months. Fusion was achieved in all

  18. Interfacial shear strength of bioactive-coated carbon fiber reinforced polyetheretherketone after in vivo implantation.

    PubMed

    Nakahara, Ichiro; Takao, Masaki; Goto, Tomoyo; Ohtsuki, Chikara; Hibino, Shigeru; Sugano, Nobuhiko

    2012-10-01

    Despite the excellent osseointegration of carbon-fiber-reinforced polyetheretherketone (CFR/PEEK) with a surface hydroxyapatite (HA) coating, the bone-implant interfacial shear strength of HA-coated CFR/PEEK after osseointegration is unclear. We examined the interfacial shear strength of HA-coated CFR/PEEK implants after in vivo implantation in a rabbit femur-implant pull-out test model. HA coating was performed by a newly developed method. Uncoated CFR/PEEK, HA-coated blasted titanium alloy, and uncoated blasted titanium alloy were used as control implants. The implants were inserted into drilled femoral cortex, and pull-out tests were conducted after 6 and 12 weeks of implantation to determine maximum interfacial shear strength. The HA-coated CFR/PEEK (15.7  ± 4.5 MPa) and HA-coated titanium alloy (14.1  ±  6.0 MPa) exhibited significantly larger interfacial shear strengths than the uncoated CFR/PEEK (7.7 ± 1.8 MPa) and the uncoated titanium alloy (7.8  ±  2.1 MPa) at 6 weeks. At 12 weeks, only the uncoated CFR/PEEK (8.3  ±  3.0 MPa) exhibited a significantly smaller interfacial shear strength, as compared to the HA-coated CFR/PEEK (17.4  ±  3.6 MPa), HA-coated titanium alloy (14.2  ±  4.8 MPa), and uncoated titanium alloy (15.0  ±  2.6 MPa). Surface analysis of the removed implants revealed detachment of the HA layer in both the HA-coated CFR/PEEK and titanium alloy implants. The proposed novel HA coating method of CFR/PEEK significantly increased interfacial shear strength between bone and CFR/PEEK. The achieved interfacial shear strength of the HA-coated CFR/PEEK implant is of the same level as that of grit-blasted titanium alloy with HA. Copyright © 2012 Orthopaedic Research Society.

  19. Creation of nanoporous TiO2 surface onto polyetheretherketone for effective immobilization and delivery of bone morphogenetic protein.

    PubMed

    Han, Cheol-Min; Jang, Tae-Sik; Kim, Hyoun-Ee; Koh, Young-Hag

    2014-03-01

    This study evaluated the utility of the creation of a nanoporous TiO2 surface to enhance the in vitro biocompatibility and in vivo osseoconductivity of polyetheretherketone (PEEK) implants by providing favorable sites for the effective immobilization of bone morphogenetic protein-2 (BMP-2). A uniform nanoporous TiO2 layer with a pore diameter of ∼70 nm was successfully created by anodizing a Ti film, which had been deposited onto a PEEK substrate via electron beam (e-beam) evaporation technique. This nanoporous, hydrophilic TiO2 surface enabled the efficient immobilization of BMP-2, resulting in a remarkable enhancement in in vitro biocompatibility that was assessed in terms of cell attachment, proliferation, and differentiation. The in vivo animal tests also confirmed that the nanoporous TiO2 surface immobilized with BMP-2 could significantly enhance the osseoconductivity of PEEK implants. The BMP-immobilized PEEK implant with the nanoporous TiO2 surface showed much higher bone-to-implant contact (BIC) ratio (60%) than the bare PEEK (30%), PEEK with the nanoporous TiO2 surface (50%) and even BMP-immobilized PEEK without the nanoporous TiO2 surface (32%). Copyright © 2013 Society of Plastics Engineers.

  20. Influence of polyetheretherketone coatings on the Ti-13Nb-13Zr titanium alloy's bio-tribological properties and corrosion resistance.

    PubMed

    Sak, Anita; Moskalewicz, Tomasz; Zimowski, Sławomir; Cieniek, Łukasz; Dubiel, Beata; Radziszewska, Agnieszka; Kot, Marcin; Łukaszczyk, Alicja

    2016-06-01

    Polyetheretherketone (PEEK) coatings of 70-90μm thick were electrophoretically deposited from a suspension of PEEK powder in ethanol on near-β Ti-13Nb-13Zr titanium alloy. In order to produce good quality coatings, the composition of the suspension (pH) and optimized deposition parameters (applied voltage and time) were experimentally selected. The as-deposited coatings exhibited the uniform distribution of PEEK powders on the substrate. The subsequent annealing at a temperature above the PEEK melting point enabled homogeneous, semi-crystalline coatings with spherulitic morphology to be produced. A micro-scratch test showed that the coatings exhibited very good adhesion to the titanium alloy substrate. Coating delamination was not observed even up to a maximal load of 30N. The PEEK coatings significantly improved the tribological properties of the Ti-13Nb-13Zr alloy. The coefficient of friction was reduced from 0.55 for an uncoated alloy to 0.40 and 0.12 for a coated alloy in a dry sliding and sliding in Ringer's solution, respectively. The PEEK coatings exhibited excellent wear resistance in both contact conditions. Their wear rate was more than 200 times smaller compared with the wear rate of the uncoated Ti-13Nb-13Zr alloy. The obtained results indicate that electrophoretically deposited PEEK coatings on the near-β titanium alloy exhibit very useful properties for their prospective tribological applications in medicine.

  1. New modified polyetheretherketone membrane for liver cell culture in biohybrid systems: adhesion and specific functions of isolated hepatocytes.

    PubMed

    De Bartolo, L; Morelli, S; Rende, M; Gordano, A; Drioli, E

    2004-08-01

    There has been growing interest in innovative materials with physico-chemical properties that provide improved blood/cell compatibility. We propose new polymeric membranes made of modified polyetheretherketone (PEEK-WC) as materials with potential for use in biohybrid devices. PEEK-WC exhibits high chemical, thermal stability and mechanical resistance. Owing to its lack of crystallinity this polymer can be used for preparing membranes with cheap and flexible methods. We compared the properties of PEEK-WC membranes to polyurethane membranes prepared using the same phase inverse technique and commercial membranes. The physico-chemical properties of the membranes were characterised by contact angle measurements. The different parameters acid (gamma+), base (gamma-) and Lifshitz-van der Waals (gammaLW) of the surface free energy were calculated according to Good-van Oss's model. We evaluated the cytocompatibility of PEEK-WC membranes by culturing hepatocytes isolated from rat liver. Cell adhesion and metabolic behaviour in terms of ammonia elimination, urea synthesis and protein synthesis were evaluated during the first days of culture. Liver cells adhered and formed three-dimensional aggregates on the most tested membranes. PEEK-WC membranes promoted hepatocyte adhesion most effectively. Urea synthesis, ammonia elimination and protein synthesis improved significantly when cells adhered to PEEK-WC membrane. The considerable metabolic activities of cells cultured on this membrane confirmed the good structural and physico-chemical properties of the PEEK-WC membrane that could be a promising biomaterial for cell culture in biohybrid devices.

  2. Bioactivity of sol-gel-derived TiO2 coating on polyetheretherketone: In vitro and in vivo studies.

    PubMed

    Shimizu, Takayoshi; Fujibayashi, Shunsuke; Yamaguchi, Seiji; Yamamoto, Koji; Otsuki, Bungo; Takemoto, Mitsuru; Tsukanaka, Masako; Kizuki, Takashi; Matsushita, Tomiharu; Kokubo, Tadashi; Matsuda, Shuichi

    2016-04-15

    A polyetheretherketone (PEEK) surface was modified using a sol-gel-derived TiO2 coating in order to confer bone-bonding ability. To enhance the bonding strength of the coating layer, pretreatment with either O2 plasma or sandblasting was performed prior to sol-gel coating. Additionally, post-treatment with acid was carried out to confer apatite (calcium phosphate)-forming ability to the surface. Biomechanical and histological analyses performed using an in vivo rabbit tibia model showed that PEEK surfaces modified with sol-gel-derived TiO2 and acid post-treatment had better bone-bonding properties than uncoated PEEK surfaces. These modified surfaces also performed well in terms of their in vitro cell responses due to their modified surface chemistries and topographies. Although O2 plasma or sandblasting treatment were, for the most part, equivocal in terms of performance, we conclude that sol-gel-derived TiO2 coating followed by acid post-treatment significantly improves the bone bonding ability of PEEK surfaces, thus rendering them optimal for their use in surgical implants. The role of polyetheretherketone (PEEK) as an alternative biomaterial to conventional metallic implant materials has become increasingly important. However, its low bone bonding ability is yet to be resolved. This in vivo and in vitro investigation on the functionalization of PEEK surfaces highlights the utility of this material in clinical interventions that require implants, and may extend range of applications of PEEK. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Enhanced osteointegration on tantalum-implanted polyetheretherketone surface with bone-like elastic modulus.

    PubMed

    Lu, Tao; Wen, Jin; Qian, Shi; Cao, Huiliang; Ning, Congqin; Pan, Xiaoxia; Jiang, Xinquan; Liu, Xuanyong; Chu, Paul K

    2015-05-01

    Polyetheretherketone (PEEK) possesses a similar elastic modulus as bones but yet suffers from bio-inertness and poor osteogenesis. In this work, tantalum ions are implanted energetically into PEEK by plasma immersion ion implantation (PIII) to form Ta2O5 nanoparticles in the near surface. Nanoindentation reveals that the surface elastic modulus of the Ta ion implanted PEEK is closer to that of human cortical bones. In vitro cell adhesion, alkaline phosphatase activity, collagen secretion, extracellular matrix mineralization, and real-time PCR analyses disclose enhanced adhesion, proliferation, and osteogenic differentiation of rat bone mesenchymal stem cells (bMSCs) on the Ta-PIII modified PEEK. In vivo evaluation of the cortico-cancellous rat femur model by means of micro-CT, sequential fluorescent labeling, and histological analysis after 8 weeks confirms significantly improved osteointegration. The bone-like elastic modulus and modified surface topography of the Ta-PIII modified PEEK synergistically induce osteogenic differentiation of bMSCs and the surface-modified materials have large potential in dental and orthopedic implants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Hydroxyapatite coating on PEEK implants: Biomechanical and histological study in a rabbit model.

    PubMed

    Durham, John W; Montelongo, Sergio A; Ong, Joo L; Guda, Teja; Allen, Matthew J; Rabiei, Afsaneh

    2016-11-01

    A bioactive two-layer coating consisting of hydroxyapatite (HA) and yttria-stabilized zirconia (YSZ) was investigated on cylindrical polyetheretherketone (PEEK) implants using ion beam assisted deposition (IBAD). Post-deposition heat treatments via variable frequency microwave annealing with and without subsequent autoclaving were used to crystallize the as-deposited amorphous HA layer. Microstructural analysis, performed by TEM and EDS, showed that these methods were capable of crystallizing HA coating on PEEK. The in vivo response to cylindrical PEEK samples with and without coating was studied by implanting uncoated PEEK and coated PEEK implants in the lateral femoral condyle of 18 rabbits. Animals were studied in two groups of 9 for observation at 6 or 18weeks post surgery. Micro-CT analysis, histology, and mechanical pull-out tests were performed to determine the effect of the coating on osseointegration. The heat-treated HA/YSZ coatings showed improved implant fixation as well as higher bone regeneration and bone-implant contact area compared to uncoated PEEK. The study offers a novel method to coat PEEK implants with improved osseointegration.

  5. Fine grained osseointegrative coating improves biocompatibility of PEEK in heterotopic sheep model

    PubMed Central

    Verleye, Gino B.M.; Smeets, Dirk; Van Hauwermeiren, Hadewych Y.R.; Loeckx, Dirk; Willems, Karel; Siau, Vincent G.M.G.G.B.; Lauweryns, Philippe J.M.E.

    2015-01-01

    Background and aim Polyetheretherketone (PEEK) materials already have been used successfully in orthopedic and especially spine surgery. PEEK is radiolucent and comparable with bone regarding elasticity. However, PEEK is inert and the adhesion of PEEK implants to bone tissue proceeds slowly because of their relatively low biocompatibility. The aim of the study is to evaluate the effect of titanium and CaP coating on the adhesion of bone tissue. Material and Methods Six adult sheep (body weight 57.6 ± 3.9 kg) were included in this study. Three different types of cylindrical dowels (12 mm length x 8 mm diameter) were implanted in long bones (tibia and femur): PEEK dowels without coating (the control group), and PEEK dowels with a nanocoating of calcium phosphate (CaP group) or titanium (titanium group). Animals were sacrificed after 6, 12 and 26 weeks. Dowels were explanted for micro CT and histology. Results Bone implant contact (BIC) ratio was significantly higher in the titanium versus control groups in the 6 to 12 weeks period (p = 0.03). The ratio between bone volume and tissue volume (BV/TV) was significantly higher in titanium versus control in the 6 to 12 weeks period (p = 0.02). A significant correlation between BIC and BV/TV was seen (r = 0.85, p < 0.05). Conclusion Coating of PEEK dowels with a nanocoating of titanium has beneficial effects on adhesion of bone tissue. PMID:26273553

  6. Fine grained osseointegrative coating improves biocompatibility of PEEK in heterotopic sheep model.

    PubMed

    Meers, Caroline M F; Verleye, Gino B M; Smeets, Dirk; Van Hauwermeiren, Hadewych Y R; Loeckx, Dirk; Willems, Karel; Siau, Vincent G M G G B; Lauweryns, Philippe J M E

    2015-01-01

    Polyetheretherketone (PEEK) materials already have been used successfully in orthopedic and especially spine surgery. PEEK is radiolucent and comparable with bone regarding elasticity. However, PEEK is inert and the adhesion of PEEK implants to bone tissue proceeds slowly because of their relatively low biocompatibility. The aim of the study is to evaluate the effect of titanium and CaP coating on the adhesion of bone tissue. Six adult sheep (body weight 57.6 ± 3.9 kg) were included in this study. Three different types of cylindrical dowels (12 mm length x 8 mm diameter) were implanted in long bones (tibia and femur): PEEK dowels without coating (the control group), and PEEK dowels with a nanocoating of calcium phosphate (CaP group) or titanium (titanium group). Animals were sacrificed after 6, 12 and 26 weeks. Dowels were explanted for micro CT and histology. Bone implant contact (BIC) ratio was significantly higher in the titanium versus control groups in the 6 to 12 weeks period (p = 0.03). The ratio between bone volume and tissue volume (BV/TV) was significantly higher in titanium versus control in the 6 to 12 weeks period (p = 0.02). A significant correlation between BIC and BV/TV was seen (r = 0.85, p < 0.05). Coating of PEEK dowels with a nanocoating of titanium has beneficial effects on adhesion of bone tissue.

  7. Flexible Stabilisation of the Degenerative Lumbar Spine Using PEEK Rods.

    PubMed

    Benezech, Jacques; Garlenq, Bruno; Larroque, Gilles

    2016-01-01

    Posterior lumbar interbody fusion using cages, titanium rods, and pedicle screws is considered today as the gold standard of surgical treatment of lumbar degenerative disease and has produced satisfying long-term fusion rates. However this rigid material could change the physiological distribution of load at the instrumental and adjacent segments, a main cause of implant failure and adjacent segment disease, responsible for a high rate of further surgery in the following years. More recently, semirigid instrumentation systems using rods made of polyetheretherketone (PEEK) have been introduced. This clinical study of 21 patients focuses on the clinical and radiological outcomes of patients with lumbar degenerative disease treated with Initial VEOS PEEK(®)-Optima system (Innov'Spine, France) composed of rods made from PEEK-OPTIMA(®) polymer (Invibio Biomaterial Solutions, UK) without arthrodesis. With an average follow-up of 2 years and half, the chances of reoperation were significantly reduced (4.8%), quality of life was improved (ODI = 16%), and the adjacent disc was preserved in more than 70% of cases. Based on these results, combined with the biomechanical and clinical data already published, PEEK rods systems can be considered as a safe and effective alternative solution to rigid ones.

  8. Flexural behavior of PEEK materials for dental application.

    PubMed

    Schwitalla, Andreas Dominik; Spintig, Tobias; Kallage, Ilona; Müller, Wolf-Dieter

    2015-11-01

    The high-performance thermoplastic polymer PEEK (poly-ether-ether-ketone) is used as alternative implant material to metals since 1998 in many medical fields due to its bone-like mechanical properties. These iso-elastic characteristics of PEEK lead to the assumption, that it could represent a viable alternative to conventional materials also in the field of dentistry. Therefore the mechanical properties of different PEEK-compounds should be eavuated vie the three-point bending test. 150 specimens of 11 different PEEK-compounds were tested via a three-point bending test using a universal testing machine (Z010, Zwick GmbH & Co, Ulm, Germany) after dry storage on the one hand and after incubation at 37°C in Ringer solution (Fa. Braun Melsungen AG, Melsungen, Deutschland) for one day, 7 days, 28 days und 84 days on the other hand and the material parameters bending modulus and bending strength were evaluated. The results regarding the bending moduli ranged from 2.73±0.26GPa for an unfilled brand to 47.27±10.3GPa for a carbon fiber reinforced PEEK with unidirectional continuous carbon fibers. Accordingly the bending strengths of these two material types ranged from 170.37±19.31MPa to 1009.63±107.33MPa. All tested specimens showed higher values than the prevailing minimum strength for plastic materials and their application in dentistry of 65MPa (DIN EN ISO 10477). This underlines the applicability of PEEK in dentistry and points out the possibility to offer patients metal free restorations, especially in the presence of allergies and/or bruxism. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  9. Carbon fiber reinforced PEEK Optima--a composite material biomechanical properties and wear/debris characteristics of CF-PEEK composites for orthopedic trauma implants.

    PubMed

    Steinberg, Ely L; Rath, Ehud; Shlaifer, Amir; Chechik, Ofir; Maman, Eran; Salai, Moshe

    2013-01-01

    The advantageous properties of carbon fiber reinforced polyetheretherketone (CF-PEEK) composites for use as orthopedic implants include similar modulus to bone and ability to withstand prolonged fatigue strain. The CF-PEEK tibial nail, dynamic compression plate, proximal humeral plate and distal radius volar plate were compared biomechanically (by four-point bending, static torsion of the nail, and bending fatigue) and for wear/debris (by amount of the debris generated at the connection between the CF-PEEK plate and titanium alloy screws) to commercially available devices. Four-point bending stress of the tibial nail and dynamic and distal radius plates yielded characteristics similar to other commercially available devices. The distal volar plate bending structural stiffness of the CF-PEEK distal volar plate was 0.542 Nm2 versus 0.376 Nm2 for the DePuy's DVR anatomic volar plate. The PHILOS proximal humeral internal locking system stainless steel plate was much stronger (6.48 Nm2) than the CF-PEEK proximal humeral plate (1.1 Nm2). Tibial nail static torsion testing showed similar properties to other tested nails (Fixion, Zimmer and Synthes). All tested CF-PEEK devices underwent one million fatigue cycles without failure. Wear test showed a lower volume of generated particles in comparison to the common implants in use today. Thus, these tested implants were similar to commercially used devices and can be recommended for use as implants in orthopedic surgery. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Covalent attachment of cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) to poly(etheretherketone) surface by tailored silanization layers technique

    NASA Astrophysics Data System (ADS)

    Zheng, Yanyan; Xiong, Chengdong; Li, Xiaoyu; Zhang, Lifang

    2014-11-01

    Poly(etheretherketone) (PEEK) is a rigid semicrystalline polymer that combines excellent mechanical properties, broad chemical resistance and bone-like stiffness and is widely used in biomedical fields. However, PEEK is naturally bioinert, leading to limited biomedical applications, especially when a direct bone-implant osteointegration is desired. In this study, a three-step reaction procedure was employed to immobilize the cell-adhesive peptide Gly-Arg-Gly-Asp (GRGD) on the surface of PEEK sheet by covalent chemical attachment to favor cell adhesion and proliferation. First, hydroxylation-pretreated PEEK surfaces were silanized with 7-Oct-1-enyltrichlorosilane (OETS) in dry cyclohexane, resulting in a silanization layer with terminal ethenyl. Second, the terminal ethylenic double bonds of the silanization layer on PEEK surface were converted to carboxyl groups through acidic potassium manganate oxidation. Finally, GRGD was covalently attached by carbodiimide mediated condensation between the carboxyl on PEEK surface and amine presents in GRGD. X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, surface profiler and water contact angle measurements were applied to characterize the modified surfaces. The effect of cells attachment and proliferation on each specimen was investigated. Pre-osteoblast cells (MC3T3-E1) attachment, spreading and proliferation were improved effectively on GRGD-modified PEEK surface. PEEK modified with GRGD on its surface has potential use in orthopedic or dental implants.

  11. Poly(ether-ether-ketone) orthopedic bearing surface modified by self-initiated surface grafting of poly(2-methacryloyloxyethyl phosphorylcholine).

    PubMed

    Kyomoto, Masayuki; Moro, Toru; Yamane, Shihori; Hashimoto, Masami; Takatori, Yoshio; Ishihara, Kazuhiko

    2013-10-01

    We investigated the production of free radicals on a poly(ether-ether-ketone) (PEEK) substrate under ultraviolet (UV) irradiation. The amount of the ketyl radicals produced from the benzophenone (BP) units in the PEEK molecular structure initially increased rapidly and then became almost constant. Our observations revealed that the BP units in PEEK acted as photoinitiators, and that it was possible to use them to control the graft polymerization of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC). This "self-initiated surface graft polymerization" method is very convenient in the absence of external photoinitiator. We also investigated the effects of the monomer concentration and UV irradiation time on the extent of the grafted PMPC layer. Furthermore, as an application to improving the durability of artificial hips, we demonstrated the nanometer-scale photoinduced grafting of PMPC onto PEEK and carbon fiber-reinforced PEEK (CFR-PEEK) orthopedic bearing surfaces and interfaces. A variety of test revealed significant improvements in the water wettability, frictional properties, and wear resistance of the surfaces and interfaces.

  12. Scaffold development using selective laser sintering of polyetheretherketone-hydroxyapatite biocomposite blends.

    PubMed

    Tan, K H; Chua, C K; Leong, K F; Cheah, C M; Cheang, P; Abu Bakar, M S; Cha, S W

    2003-08-01

    In tissue engineering (TE), temporary three-dimensional scaffolds are essential to guide cell proliferation and to maintain native phenotypes in regenerating biologic tissues or organs. To create the scaffolds, rapid prototyping (RP) techniques are emerging as fabrication techniques of choice as they are capable of overcoming many of the limitations encountered with conventional manual-based fabrication processes. In this research, RP fabrication of solvent free porous polymeric and composite scaffolds was investigated. Biomaterials such as polyetheretherketone (PEEK) and hydroxyapatite (HA) were experimentally processed on a commercial selective laser sintering (SLS) RP system. The SLS technique is highly advantageous as it provides good user control over the microstructures of created scaffolds by adjusting the SLS process parameters. Different weight percentage (wt%) compositions of physically mixed PEEK/HA powder blends were sintered to assess their suitability for SLS processing. Microstructural assessments of the scaffolds were conducted using electron microscopy. The results ascertained the potential of SLS-fabricated TE scaffolds.

  13. Elevated cytokine expression of different PEEK wear particles compared to UHMWPE in vivo.

    PubMed

    Lorber, V; Paulus, A C; Buschmann, A; Schmitt, B; Grupp, T M; Jansson, V; Utzschneider, Sandra

    2014-01-01

    Due to their mechanical properties, there has been growing interest in poly-ether-ether-ketone (PEEK) and its composites as bearing material in total and unicompartmental knee arthroplasty. The aim of this study was to analyze the biological activity of wear particles of two different (pitch and PAN) carbon-fiber-reinforced- (CFR-) PEEK varieties in comparison to ultra-high-molecular-weight-polyethylene (UHMWPE) in vivo. The authors hypothesized no difference between the used biomaterials. Wear particle suspensions of the particulate biomaterials were injected into knee joints of Balb/c mice, which were sacrificed after seven days. The cytokine expression (IL-1β, IL-6, TNF-α) was analyzed immunohistochemically in the synovial layer, the adjacent bone marrow and the articular cartilage. Especially in the bone marrow of the two CFR-PEEK varieties there were increased cytokine expressions compared to the control and UHMWPE group. Furthermore, in the articular cartilage the CFR-PEEK pitch group showed an enhanced cytokine expression, which could be a negative predictor for the use in unicondylar knee systems. As these data suggest an increased proinflammatory potential of CFR-PEEK and its composites in vivo, the initial hypothesis had to be refuted. Summarizing these results, CFR-PEEK seems not to be an attractive alternative to UHMWPE as a bearing material, especially in unicompartmental knee arthroplasty.

  14. Coating of carbon fiber-reinforced polyetheretherketone implants with titanium to improve bone apposition.

    PubMed

    Devine, Declan M; Hahn, Joachim; Richards, R Geoffery; Gruner, Heiko; Wieling, Ronald; Pearce, Simon G

    2013-05-01

    Carbon fiber-reinforced polyetheretherketone (CF/PEEK) is a thermoplastic composite biomaterial exhibiting properties suitable for load-bearing orthopedic implants. However, the hydrophobic surface of CF/PEEK implants induces the deposition of a peri-implant fibrous tissue capsule preventing bone apposition. However, if bone apposition was improved, the use of CF/PEEK in orthopedics could be increased as it has many advantages compared with metallic implants. In this study, CF/PEEK screws were coated with titanium (Ti) using two different techniques, namely vacuum plasma spraying (VPS) and physical vapor deposition (PVD) with uncoated screws as controls. These coatings were characterized and implanted in a loaded sheep tibia model. In the characterization of the screw surfaces using microscopy techniques, the uncoated screws were seen to have an irregular surface. The PVD coating appeared smooth and consistent, whereas the VPS coating appeared to be a rough coating with some inhomogeneities, which did not cover the entire surface area. Nevertheless, in the ex vivo analysis the VPS-coated screws had a screw removal torque which was statistically greater than uncoated and PVD-coated screws (p ≤ 0.002 for both comparisons). Additionally, the VPS-coated screws had a statistically higher bone contact area than the uncoated screws (p = 0.006), whereas no statistical difference was detected between VPS and PVD coating types (p = 0.11). Thereby illustrating that Ti coating of CF/PEEK screws significantly improve bone apposition and removal torque compared with uncoated CF/PEEK screws. Copyright © 2012 Wiley Periodicals, Inc.

  15. Enhancement of osteogenesis on micro/nano-topographical carbon fiber-reinforced polyetheretherketone-nanohydroxyapatite biocomposite.

    PubMed

    Xu, Anxiu; Liu, Xiaochen; Gao, Xiang; Deng, Feng; Deng, Yi; Wei, Shicheng

    2015-03-01

    As an FDA-approved implantable material, carbon fiber-reinforced polyetheretherketone (CFRPEEK) possesses excellent mechanical properties similar to those of human cortical bone and is a prime candidate to replace conventional metallic implants. The bioinertness and inferior osteogenic properties of CFRPEEK, however, limit its clinical application as orthopedic/dental implants. The present work aimed at developing a novel carbon fiber-reinforced polyetheretherketone-nanohydroxyapatite (PEEK/CF/n-HA) ternary biocomposite with micro/nano-topographical surface for the enhancement of the osteogenesis as a potential bioactive material for bone grafting and bone tissue-engineering applications. The combined modification of oxygen plasma and sand-blasting could improve the hydrophily and generate micro/nano-topographical structures on the surface of the CFRPEEK-based ternary biocomposite. The results clearly showcased that the micro-/nano-topographical PEEK/n-HA/CF ternary biocomposite demonstrated the outstanding ability to promote the proliferation and differentiation of MG-63 cells in vitro as well as to boost the osseointegration between implant and bone in vivo, thereby boding well application to bone tissue engineering.

  16. Flexible Stabilisation of the Degenerative Lumbar Spine Using PEEK Rods

    PubMed Central

    Benezech, Jacques; Garlenq, Bruno; Larroque, Gilles

    2016-01-01

    Posterior lumbar interbody fusion using cages, titanium rods, and pedicle screws is considered today as the gold standard of surgical treatment of lumbar degenerative disease and has produced satisfying long-term fusion rates. However this rigid material could change the physiological distribution of load at the instrumental and adjacent segments, a main cause of implant failure and adjacent segment disease, responsible for a high rate of further surgery in the following years. More recently, semirigid instrumentation systems using rods made of polyetheretherketone (PEEK) have been introduced. This clinical study of 21 patients focuses on the clinical and radiological outcomes of patients with lumbar degenerative disease treated with Initial VEOS PEEK®-Optima system (Innov'Spine, France) composed of rods made from PEEK-OPTIMA® polymer (Invibio Biomaterial Solutions, UK) without arthrodesis. With an average follow-up of 2 years and half, the chances of reoperation were significantly reduced (4.8%), quality of life was improved (ODI = 16%), and the adjacent disc was preserved in more than 70% of cases. Based on these results, combined with the biomechanical and clinical data already published, PEEK rods systems can be considered as a safe and effective alternative solution to rigid ones. PMID:26981285

  17. Wear studies on the likely performance of CFR-PEEK/CoCrMo for use as artificial joint bearing materials.

    PubMed

    Scholes, S C; Unsworth, A

    2009-01-01

    It is well known that a reduction in the volume of wear produced by articulating surfaces in artificial joints is likely to result in a lower incidence of failure due to wear particle induced osteolysis. Therefore, new materials have been introduced in an effort to produce bearing surfaces with lower, more biologically acceptable wear. Polyetheretherketone (PEEK-OPTIMA) has been successfully used in a number of implant applications due to its combination of mechanical strength and biocompatibility. Pin-on-plate wear tests were performed on various combinations of PEEK-OPTIMA and carbon fibre reinforced PEEK-OPTIMA (CFR-PEEK) against various CoCrMo alloys to assess the potential of this material combination for use in orthopaedic implants. The PEEK/low carbon CoCrMo produced the highest wear. CFR-PEEK against high carbon or low carbon CoCrMo provided low wear factors. Pin-on-plate tests performed on ultra-high molecular weight polyethylene (UHMWPE) against CoCrMo (using comparable test conditions) have shown similar or higher wear than that found for CFR-PEEK/CoCrMo. This study gives confidence in the likelihood of this material combination performing well in orthopaedic applications.

  18. In vivo implant fixation of carbon fiber-reinforced PEEK hip prostheses in an ovine model.

    PubMed

    Nakahara, Ichiro; Takao, Masaki; Bandoh, Shunichi; Bertollo, Nicky; Walsh, William R; Sugano, Nobuhiko

    2013-03-01

    Carbon fiber-reinforced polyetheretherketone (CFR/PEEK) is theoretically suitable as a material for use in hip prostheses, offering excellent biocompatibility, mechanical properties, and the absence of metal ions. To evaluate in vivo fixation methods of CFR/PEEK hip prostheses in bone, we examined radiographic and histological results for cementless or cemented CFR/PEEK hip prostheses in an ovine model with implantation up to 52 weeks. CFR/PEEK cups and stems with rough-textured surfaces plus hydroxyapatite (HA) coatings for cementless fixation and CFR/PEEK cups and stems without HA coating for cement fixation were manufactured based on ovine computed tomography (CT) data. Unilateral total hip arthroplasty was performed using cementless or cemented CFR/PEEK hip prostheses. Five cementless cups and stems and six cemented cups and stems were evaluated. On the femoral side, all cementless stems demonstrated bony ongrowth fixation and all cemented stems demonstrated stable fixation without any gaps at both the bone-cement and cement-stem interfaces. All cementless cases and four of the six cemented cases showed minimal stress shielding. On the acetabular side, two of the five cementless cups demonstrated bony ongrowth fixation. Our results suggest that both cementless and cemented CFR/PEEK stems work well for fixation. Cup fixation may be difficult for both cementless and cemented types in this ovine model, but bone ongrowth fixation on the cup was first seen in two cementless cases. Cementless fixation can be achieved using HA-coated CFR/PEEK implants, even under load-bearing conditions.

  19. Comparison of Radiologic Outcomes of Different Methods in Single-Level Anterior Cervical Discectomy and Fusion

    PubMed Central

    Kwon, O Ik; Lee, Sang Weon; Song, Geun Sung

    2016-01-01

    Objective Anterior cervical discectomy and fusion (ACDF) is a choice of surgical procedure for cervical degenerative diseases associated with radiculopathy or myelopathy. However, the patients undergoing ACDF still have problems. The purpose of the present study is to evaluate the radiologic results of 3 different methods in single-level ACDF. Methods We conducted a retrospective collection of radiological data from January 2011 to December 2014. A total of 67 patients were included in this study. The patients were divided into 3 groups by operation procedure: using stand-alone cage (group cage, n=20); polyether-ether-ketone (PEEK)-titanium combined anchored cage (group AC, n=21); and anterior cervical cage-plate (group CP, n=26). Global cervical lordosis (C2-C7 Cobb angle), fused segment height, fusion rate, and cervical range of motion (ROM) were measured and analyzed at serial preoperative, postoperative, 6-month, and final 1-year follow-up. Results Successful bone fusion was achieved in all patients at the final follow-up examination; however, the loss of disc height over 3 mm at the surgical level was observed in 6 patients in group cage. Groups AC and CP yielded significantly better outcomes than group cage in fused segment height and cervical ROM(p=0.01 and p=0.02, respectively). Furthermore, group AC had similar radiologic outcomes to those of group CP. Conclusion The PEEK-titanium combined anchored cage may be a good alternative procedure in terms of reducing complications induced by plate after ACDF. PMID:27799985

  20. The efficacy of the synthetic interbody cage and Grafton for anterior cervical fusion.

    PubMed

    Park, Hyun-Woong; Lee, Jung-Kil; Moon, Sung-Jun; Seo, Seung-Kweon; Lee, Jae-Hyun; Kim, Soo-Han

    2009-08-01

    Prospective study of 31 patients who underwent anterior cervical fusion. To investigate the efficacy of polyetheretherketone (PEEK) cages and demineralized bone matrix (DBM) for anterior cervical discectomy and fusion (ACDF). Although high fusion rates can be achieved with autogenous bone grafts, donor-site morbidity affects the patient's satisfaction with the surgical outcome. Thirty-one consecutive patients treated with ACDF using the PEEK cage with DBM (Grafton, Osteotech, Inc., Shrewsbury, NJ) at 42 levels were prospectively evaluated with a minimum of 12-month follow-up (mean: 16 months). Twenty-one patients underwent a single-level ACDF, 9 patients underwent a 2-level ACDF, and 1 patient had a 3-level ACDF. The affected level was C3-C4 in 7 patients; C4-C5 in 9, C5-C6 in 16, and C6-C7 in 10. The neurologic outcomes were evaluated using the VAS score for neck and arm pain and the Japanese Orthopedic Association scoring system for myelopathy at 3, 6, and 12 months. The cervical lordosis and fusion status were assessed on radiographs including flexion/extension radiographs. At 12 months, the radiographs demonstrated grades I, II, and III new bone formation at 1, 13, and 28 levels, respectively. There was a significant improvement in both the neck and arm pain and a significant improvement in the Japanese Orthopedic Association scores at the last follow-up. There was no case with implant-related complications such as cage failure or migration, and no complications associated with the use of Grafton. ACDF using the Solis cage packed with Grafton demonstrated good clinical and radiologic outcomes. The fusion rate was comparable with the published results of the traditional ACDF using tricortical iliac crest grafts. Therefore, the results of this study suggest that the ongoing use of the PEEK cage packed with DBM and autologous bone chips in ACDF is a safe and effective alternative to the gold standard of autologous iliac bone grafts.

  1. Subsidence after single-level anterior cervical fusion with a stand-alone cage.

    PubMed

    Park, Jae-Young; Choi, Ki-Young; Moon, Bong Ju; Hur, Hyuk; Jang, Jae-Won; Lee, Jung-Kil

    2016-11-01

    To investigate the risk factors for subsidence in patients treated with stand-alone anterior cervical discectomy and fusion (ACDF) using polyetheretherketone (PEEK) cages for single-level degenerative cervical disease. Seventy-seven consecutive patients who underwent single-level stand-alone ACDF with a PEEK cage between 2005 and 2012 were included. Subsidence was defined as a decrease in the interbody height of more than 3mm on radiographs at the 1-year follow-up compared with that in the immediate post-operative image. Patients were divided into the subsidence and non-subsidence groups. The following factors were investigated in relation to the occurrence of subsidence: age, pre-operative overall cervical sagittal angle, segmental angle of the operated level, interbody height, cage height, cage devices and cage location (distance between anterior margin of the body endplate and that of the cage). The clinical outcomes were assessed with visual analog scale, modified Japanese Orthopedic Association score and neck disability index. Twenty-six out of the 77 (33.8%) patients had radiological signs of cage subsidence. Solid fusion was achieved in 25 out of the 26 patients (96.2%) in the subsidence group and in 47 out of the 51 patients (92.2%) in the non-subsidence group. More than 3mm distance between anterior margin of the vertebral body and that of the cage was significantly associated with subsidence (p<0.05). However, subsidence did not correlate with fusion rate or clinical outcomes. Cage location was the only significant risk factor. Therefore, cage location should be taken into consideration during stand-alone ACDF using PEEK cages. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. [The finite element analysis of polyetheretherketone/hydroxyapatite/carbon fiber cage].

    PubMed

    Liu, Xueyong; Zhu, Hongxin; Jing, Yanfeng; Sui, Guoxin; Zhang, Zongfu

    2013-08-01

    To compare the bio-mechanical characteristics of cages of two types, i. e., polyetheretherketone/ hydroxyapatite/carbon fiber (PEEK/HA/CF) and titanium combined with internal pedicle screw fixation in lumbar model, and to provide experimental evidences for clinical application, we constructed a three-dimensional finite element model of an intact L2-L4 segment by using computer tomography scans of a healthy male. The three-dimensional finite element models of an intact L2-L4 segment and single cage plus bilateral vertebral pedicle screw fixation were established. The angular motion of fused segment and stress distribution in the bone graft and cage and L3 inferior endplate under different loads were recorded. The result showed that the peak Von Mises stresses of the bone graft of PEEK/HA/CF group were at least 2.2 time as that of titanium group. The peak Von Mises stresses of L3 inferior endplate of the titanium group were at least 2. 3 times as that of PEEK/HA/CF group. These stresses were concentrated at places where the cage interfaced with the endplate. The angular variation of the titanium group showed similarity to PEEK/HA/CF group. The PEEK/HA/CF cage could provide stability similar to that of titanium cage in the presence of posterior instrumentation. It could increase the load transfer through the bone graft and promote the bone fusion. It could also reduce the stresses in endplates adjacent to the cage and reduce the subsidence of the cage.

  3. Polyetheretherketone implants for the repair of large cranial defects: a 3-center experience.

    PubMed

    Rosenthal, Guy; Ng, Ivan; Moscovici, Samuel; Lee, Kah K; Lay, Twyila; Martin, Christine; Manley, Geoffrey T

    2014-11-01

    Calvarial reconstruction of large cranial defects following decompressive surgery is challenging. Autologous bone cannot always be used due to infection, fragmentation, bone resorption, and other causes. Polyetheretherketone (PEEK) is a synthetic material that has many advantages in cranial-repair surgery, including strength, stiffness, durability, and inertness. To describe our experience with custom-made PEEK implants for the repair of large cranial defects in 3 institutions: San Francisco General Hospital, Hadassah-Hebrew University Hospital, and the National Neuroscience Institute, Singapore. A preoperative high-resolution computed tomography scan was obtained for each patient for design of the PEEK implant. Cranioplasty was performed via standard technique with the use of self-tapping titanium screws and miniplates. Between 2006 and 2012, 66 cranioplasties with PEEK implants were performed in 65 patients (46 men, 19 women, mean age 35 ± 14 years) for repair of large cranial defects. There were 5 infections of implants and 1 wound breakdown requiring removal of the implant (infection and surgical removal rates of 7.6% and 9.1%, respectively). Two patients required drainage of postoperative hematoma (overall surgical complication rate, 12.7%). Nonsurgical complications in 5 patients included seizures, nonoperative collection, and cerebrospinal fluid rhinorrhea that resolved spontaneously. Overall median patient or family satisfaction with the cranioplasty and aesthetic result was good, 4 on a scale of 5. Temporal wasting was the main aesthetic concern. Custom-designed PEEK implants are a good option for patients with large cranial defects. The rate of complications is comparable to other implants or autologous bone. Given the large size of these defects, the aesthetic results are good.

  4. Tensile bond strength of veneering resins to PEEK: impact of different adhesives.

    PubMed

    Stawarczyk, Bogna; Keul, Christine; Beuer, Florian; Roos, Malgorzata; Schmidlin, Patrick R

    2013-01-01

    This study tested tensile bond strength (TBS) between veneering resins and polyetheretherketone (PEEK) after pre-treatment with adhesive systems. Five-hundred-seventy-six PEEK disks were fabricated, air-abraded and divided into six pre-treatment groups (n=96/group): Z-Prime Plus, Ambarino P60, Monobond Plus, Visio.link, Signum PEEK Bond, and control group without pre-treatment. Each group was divided into three subgroups of different veneering resins (n=32): Sinfony, GC Gradia and VITA VM LC. After specimen preparation with a bond area of 6.6 mm(2), half of each subgroup (n=16) was tested initially, and the other half was thermo-cycled. TBS measurements were analysed by three-way and one-way ANOVA, t-test and Weibull statistics. Groups without pre-treatment and groups pre-treated by Z-Prime Plus and Ambarino P60 showed no TBS. Pre-treatment with Monobond Plus increased the TBS values. The highest TBS before and after thermo-cycling between PEEK and all tested veneering resins was observed for groups pre-treated with Visio.link and Signum PEEK Bond.

  5. PEEK (polyether-ether-ketone)-coated nitinol wire: Film stability for biocompatibility applications

    NASA Astrophysics Data System (ADS)

    Sheiko, Nataliia; Kékicheff, Patrick; Marie, Pascal; Schmutz, Marc; Jacomine, Leandro; Perrin-Schmitt, Fabienne

    2016-12-01

    High quality biocompatible poly-ether-ether-ketone (PEEK) coatings were produced on NiTi shape memory alloy wires using dipping deposition from colloidal aqueous PEEK dispersions after substrate surface treatment. The surface morphology and microstructure were investigated by Scanning Electron Microscopy at every step of the process from the as-received Nitinol substrate to the ultimate PEEK-coated NiTi wire. Nanoscratch tests were carried out to access the adhesive behavior of the polymer coated film to the NiTi. The results indicate that the optimum process conditions in cleaning, chemical etching, and electropolishing the NiTi, were the most important and determining parameters to be achieved. Thus, high quality PEEK coatings were obtained on NiTi wires, straight or curved (even with a U-shape) with a homogeneous microstructure along the wire length and a uniform thickness of 12 μm without any development of cracks or the presence of large voids. The biocompatibility of the PEEK coating film was checked in fibrobast cultured cells. The coating remains stable in biological environment with negligible Ni ion release, no cytotoxicity, and no delamination observed with time.

  6. Tribocorrosion behavior of veneering biomedical PEEK to Ti6Al4V structures.

    PubMed

    Sampaio, Miguel; Buciumeanu, Mihaela; Henriques, Bruno; Silva, Filipe S; Souza, Júlio C M; Gomes, José R

    2016-02-01

    In dentistry, prosthetic structures must be able to support masticatory loads combined with a high biocompatibility and wear resistance in the presence of a corrosive environment. In order to improve the simultaneous wear and corrosion response of highly biocompatible prosthetic structures, a veneering poly-ether-ether-ketone (PEEK) to Ti6Al4V substrate was assessed by tribocorrosion analyses under conditions mimicking the oral environment. Samples were synthesized by hot pressing the PEEK veneer onto Ti6Al4V cylinders. The tribocorrosion tests on Ti6Al4V or PEEK/Ti6Al4V samples were performed on a reciprocating ball-on-plate tribometer at 30N normal load, 1Hz and stroke length of 3mm. The tests were carried out in artificial saliva at 37°C. Open circuit potential (OCP) was measured before, during and after reciprocating sliding tests. The worn surfaces were characterized by scanning electron microscopy. The results revealed a lower wear rate on PEEK combined with a lower coefficient of friction (COF), when compared to Ti6Al4V. In fact, PEEK protected Ti6Al4V substrate against the corrosive environment and wear avoiding the release of metallic ions to the surrounding environment.

  7. The Use of Carbon-Fiber-Reinforced (CFR) PEEK Material in Orthopedic Implants: A Systematic Review

    PubMed Central

    Li, Chuan Silvia; Vannabouathong, Christopher; Sprague, Sheila; Bhandari, Mohit

    2015-01-01

    Carbon-fiber-reinforced polyetheretherketone (CFR-PEEK) has been successfully used in orthopedic implants. The aim of this systematic review is to investigate the properties, technical data, and safety of CFR-PEEK biomaterial and to evaluate its potential for new innovation in the design of articulating medical devices. A comprehensive search in PubMed and EMBASE was conducted to identify articles relevant to the outcomes of CFR-PEEK orthopedic implants. The search was also expanded by reviewing the reference sections of selected papers and references and benchmark reports provided by content experts. A total of 23 articles were included in this review. There is limited literature available assessing the performance of CFR-PEEK, specifically as an implant material for arthroplasty systems. Nevertheless, available studies strongly support CFR-PEEK as a promising and suitable material for orthopedic implants because of its biocompatibility, material characteristics, and mechanical durability. Future studies should continue to investigate CFR-PEEK’s potential benefits. PMID:25780341

  8. Functionalized, biocompatible, and impermeable nanoscale coatings for PEEK.

    PubMed

    Awaja, Firas; Cools, Pieter; Lohberger, Birgit; Nikiforov, Anton Yu; Speranza, Giorgio; Morent, Rino

    2017-07-01

    Biologically compatible coatings that provide hermetic seal could resolve a major technological hurdle in the attempt to replace metals with polymers for biochips and active medical implants. The use of amorphous carbon/diamond like carbon (a-C:H) coatings to hermetically seal and biologically enhance polyether-ether-ketone (PEEK) for biomedical device integration in the human body was investigated. The PEEK coating functionality (sp3/sp2 ratio), hardness and thickness (70-200nm) were controlled, by varying H2 and N2 concentration during the plasma operation with CH4. a-C:H coatings having the highest indentation modulus of 13.5GPa, originate out of a CH4 (90%) rich composition. Even in a mixture of 70/30 H2/CH4 the hardness is 4.76GPa, corresponding to hard and dense coatings. In all tested conditions of deposition coatings hardens was sufficient for the purpose of PEEK implants modification. The synthesized (a-C:H) nanoscale coatings were not water permeable as measured by the hydrolysis test, resolving the traditional challenge of swelling in wet environment. The hardness of the coatings showed strong correlations with the thickness, surprisingly however, with no correlations with the sp3/sp2 ratio. Selected non water permeable nanoscale coating on PEEK showed strong bioactivity by being viable for human osteoblast (hFOB) and human fibroblast (hGF) cells without toxicity issues. No correlation was observed between the coatings sp3/sp2 ratio and biological performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Antibacterial properties of nano-silver coated PEEK prepared through magnetron sputtering.

    PubMed

    Liu, Xiuju; Gan, Kang; Liu, Hong; Song, Xiaoqing; Chen, Tianjie; Liu, Chenchen

    2017-09-01

    We aimed to investigate the cytotoxicity and antibacterial properties of nano-silver-coated polyetheretherketone (PEEK) produced through magnetron sputtering and provide a theoretical basis for its use in clinical applications. The surfaces of PEEKs were coated with nano-silver at varying thicknesses (3, 6, 9, and 12nm) through magnetron sputtering technology. The resulting coated PEEK samples were classified into the following groups according to the thickness of the nano-silver coating: PEEK-3 (3nm), PEEK-6 (6nm), PEEK-9 (9nm), PEEK-12 (12nm), and PEEK control group. The surface microstructure and composition of each sample were observed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and energy dispersive spectrum (EDS) analysis. The water contact angle of each sample was then measured by contact angle meters. A cell counting kit (CCK-8) was used to analyze the cytotoxicity of the mouse fibroblast cells (L929) in the coated groups (n=5) and group test samples (n=6), negative control (polyethylene, PE) (n=6), and positive control group (phenol) (n=6). The antibacterial properties of the samples were tested by co-culturing Streptococcus mutans and Straphylococcus aureus. The bacteria that adhered to the surface of samples were observed by SEM. The antibacterial adhesion ability of each sample was then evaluated. SEM and AFM analysis results showed that the surfaces of control group samples were smooth but compact. Homogeneous silver nano-particles (AgNPs) and nano-silver coating were uniformly distributed on the surface of the coated group samples. Compared with the control samples, the nano-silver coated samples had a significant increase in surface roughness (P<0.05) as the thickness of their nano-silver coating increased. EDS analysis showed that not only C and O but also Ag were present on the surface of the coated samples. Moreover, the water contact angle of modified samples significantly increased after nano-silver coating modification

  10. Cross-sectional examination of the damage zone in impacted specimens of carbon/epoxy and carbon/PEEK composites

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.; Magold, N. J.

    1990-01-01

    Drop weight impact testing was utilized to inflict damage on eight-ply bidirectional and unidirectional samples of carbon/epoxy and carbon/PEEK (polyetheretherketone) test specimens with impact energies ranging from 0.80 J to 1.76 J. The impacting tip was of a smaller diameter (4.2-mm) than those used in most previous studies, and the specimens were placed with a diamond wheel wafering saw through the impacted area perpendicular to the outer fibers. Photographs at 12 x magnification were taken of these cross-sections and examined. The results on the bidirectional samples show little damage until 1.13 J, at which point delaminations were seen in the epoxy specimens. The PEEK specimens showed less delamination than the epoxy specimens for a given impact energy level. The unidirectional specimens displayed more damage than the bidirectional samples for a given impact energy, with the PEEK specimens showing much less damage than the epoxy material.

  11. PEEK-Halo effect in interbody fusion.

    PubMed

    Phan, Kevin; Hogan, Jarred A; Assem, Yusuf; Mobbs, Ralph J

    2016-02-01

    Recent developments have seen poly[aryl-ether-ether-ketone] (PEEK) being increasingly used in vertebral body fusion. More novel approaches to improve PEEK have included the introduction of titanium-PEEK (Ti-PEEK) composites and coatings. This paper aims to describe a potential complication of PEEK based implants relating to poorer integration with the surrounding bone, producing a "PEEK-Halo" effect which is not seen in Ti-PEEK composite implants. We present images from two patients undergoing anterior lumbar interbody fusion (ALIF). The first patient underwent an L5/S1 ALIF using a PEEK implant whilst the second patient underwent L4/L5 ALIF using a Ti-PEEK composite implant. Evidence of osseointegration was sought using CT imaging and confirmed using histological preparations of a sheep tibia model. The PEEK-Halo effect is demonstrated by a halo effect between the PEEK implant and the bone graft on CT imaging. This phenomenon is secondary to poor osseointegration of PEEK implants. The PEEK-Halo effect was not demonstrated in the second patient who received a Ti-PEEK composite graft. Histological analysis of graft/bone interface surfaces in PEEK versus Ti-PEEK implants in a sheep model further confirmed poorer osseointegration of the PEEK implant. In conclusion, the PEEK-Halo effect is seen secondary to minimal osseointegration of PEEK at the adjacent vertebral endplate following a PEEK implant insertion. This effect is not seen with Ti-PEEK implants, and may support the role of titanium in improving the bone-implant interface of PEEK substrates. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Effects of bioactive glass and beta-TCP containing three-dimensional laser sintered polyetheretherketone composites on osteoblasts in vitro.

    PubMed

    von Wilmowsky, Cornelius; Vairaktaris, Eleftherios; Pohle, Dirk; Rechtenwald, Thomas; Lutz, Rainer; Münstedt, Helmut; Koller, Garrit; Schmidt, M; Neukam, Friedrich Wilhelm; Schlegel, Karl Andreas; Nkenke, Emeka

    2008-12-15

    Because of their excellent physical properties nonresorbable thermoplastic polymers have become more important for the field of reconstructive surgery. Aim of the present study was to investigate the effects of laser sintered polyetheretherketone (PEEK) with incorporated osteoconductive and bioactive bone substitution materials on osteoblasts in vitro. Human osteoblasts (hFOB 1.19) were seeded onto laser sintered PEEK samples containing nano-sized carbon black, beta-tricalciumphosphate (beta-TCP), and bioactive glass 45S5. Osteoblasts were investigated for cell viability, cell proliferation and cell morphology. A constant proliferation of osteoblasts could be observed on all samples with the highest values for bioactive glass containing samples at day 7 (OD 1.76 +/- 0.22) and day 14 (OD 3.75 +/- 0.31) and lowest values for beta-TCP containing probes throughout the study compared with the PEEK pure control group. Highest cell viability was observed for Bioglass containing probes (95.5 +/- 3.32)% whereas osteoblasts seeded on beta-TCP containing probes showed reduced viability (84.4 +/- 4.32)%. Laser sintered PEEK implants seem to be attractive candidates for use as bone substitutes for reconstructive surgery because of their biocompatibility, individual shape, and the possibility of compounding bioinert polymer powder with osteoconductive and bioactive materials which might benefit bone formation in vivo.

  13. Improved osteoblast compatibility of medical-grade polyetheretherketone using arc ionplated rutile/anatase titanium dioxide films for spinal implants.

    PubMed

    Tsou, Hsi-Kai; Hsieh, Ping-Yen; Chi, Meng-Hui; Chung, Chi-Jen; He, Ju-Liang

    2012-10-01

    Titanium dioxide (TiO(2)), known to exhibit good biocompatibility, is applied in this study as a thin film formed onto polyetheretherketone (PEEK) substrate, which has been widely used in spinal interbody fusion cages. For successful deposition, an arc ionplating (AIP) technique was applied to deposit TiO(2) at low deposition temperature without damaging PEEK substrate, while providing satisfactory film adhesion. This study systematically investigates the effects of TiO(2) thin film phase composition and surface characteristics, controlled by using different target current and substrate bias, on osteoblast compatibility. Experimental results showed that anatase phase (A-TiO(2)) and/or rutile phase (R-TiO(2) ) TiO(2) coatings, respectively, can be prepared in appropriate deposition conditions. Overall, the TiO(2)-coated PEEK presented better osteoblast compatibility than the bare PEEK material in terms of cell adhesion, cell proliferation, and cell differentiation abilities, as well as osteogenesis performance (as determined by levels of osteopontin, osteocalcin, and calcium content). Surface roughness and hydrophilicity of the AIP-TiO(2) films were found to be responsible for significant osteoblast cell growth. It is also noticeable that the R-TiO(2) exhibited better osteoblast compatibility than the A-TiO(2) due to the presence of negatively charged hydroxyl groups on R-TiO(2) (110) surface in nature.

  14. Improvement of mechanical properties by additive assisted laser sintering of PEEK

    SciTech Connect

    Kroh, M. Bonten, C.; Eyerer, P.

    2014-05-15

    The additive assisted laser sintering was recently developed at IKT: A carbon black (CB) additive is used to adjust the polymer's laser absorption behavior with the aim to improve the interconnection of sintered powder layers. In this paper a parameter study, Polyetheretherketone (PEEK) samples were prepared with different contents of carbon black and were laser sintered with varying thermal treatment. The samples were mechanically tested and investigated by optical light and transmission electron microscopy. An influence on the morphology at the border areas of particles and intersections of laser sintered layers was found. Depending on the viscosity of the raw material and CB content, different shapes of lamellae were observed. These (trans-) crystalline or polymorph structures, respectively, influence the thermal and mechanical behavior of the virgin PEEK. Moreover, the thermal treatment during the sintering process caused an improvement of mechanical properties like tensile strength and elongation at break.

  15. Tribological properties of polymers PI, PTFE and PEEK at cryogenic temperature in vacuum

    NASA Astrophysics Data System (ADS)

    Wang, Qihua; Zheng, Fei; Wang, Tingmei

    2016-04-01

    The effects of temperature, sliding speed and load on the tribological properties of polyimide (PI), polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK) at cryogenic temperature in vacuum were investigated using a ball-on-disk tribometer. At cryogenic temperature, polymers show higher hardness which results in decreasing contact area between the friction pairs. Moreover, the real surface area in contact between steel ball and polymer disk determines the friction coefficient instead of the formation and adhesion of the transfer film. Thus, the friction coefficients at cryogenic temperatures are lower than at room temperature. On the other hand, wear rates of the three polymers decrease as temperature decreases since molecular mobility and migration are limited at cryogenic temperatures. For the visco-elasticity of PI, PTFE and PEEK, the friction coefficients fall as the load increases.

  16. Bonding and nondestructive evaluation of graphite/PEEK composite and titanium adherends with thermoplastic adhesives

    NASA Technical Reports Server (NTRS)

    Hodges, W. T.; Tyeryar, J. R.; Berry, M.

    1985-01-01

    Bonded single overlap shear specimens were fabricated from Graphite/PEEK (Polyetheretherketone) composite adherends and titanium adherends. Six advanced thermoplastic adhesives were used for the bonding. The specimens were bonded by an electromagnetic induction technique producing high heating rates and high-strength bonds in a few minutes. This contrasts with conventionally heated presses or autoclaves that take hours to process comparable quality bonds. The Graphite/PEEK composites were highly resistant to delamination during the testing. This allowed the specimen to fail exclusively through the bondline, even at very high shear loads. Nondestructive evaluation of bonded specimens was performed ultrasonically by energizing the entire thickness of the material through the bondline and measuring acoustic impedance parameters. Destructive testing confirmed the unique ultrasonic profiles of strong and weak bonds, establishing a standard for predicting relative bond strength in subsequent specimens.

  17. Subsidence of polyetheretherketone cage after minimally invasive transforaminal lumbar interbody fusion.

    PubMed

    Kim, Moon-Chan; Chung, Hung-Tae; Cho, Jae-Lim; Kim, Dong-Jun; Chung, Nam-Su

    2013-04-01

    A retrospective case series. The aim of this study was to determine the rate of cage subsidence after minimally invasive transforaminal lumbar interbody fusion (MITLIF) conducted using a polyetheretherketone (PEEK) cage, and to identify associated risk factors. Although various rates of cage subsidence after lumbar interbody fusion have been reported, few studies have addressed subsidence rate after MITLIF using PEEK cage. A total of 104 consecutive patients who had undergone MITLIF using a PEEK cage with a minimum follow-up of 2 years were included in this study. Cage subsidence was defined to have occurred when a cage was observed to sink into an adjacent vertebral body by ≥2 mm on the postoperative or serial follow-up lateral radiographs. The demographic variables considered to affect cage subsidence were the following: age, sex, body mass index, bone mineral density, diagnosis, number of fusion segment, and the quality/quantity of back muscle, and the cage-related variables considered were: level of fusion, intervertebral angle, cage size, cage position, and postoperative distraction of disc height. Logistic regression analysis was conducted to explore relations between these variables and cage subsidence. : For the 122 cages inserted, the rate of cage subsidence was 14.8% (18 cages), and cage subsidence occurred within 7.2±8.5 (1-25) months of surgery. The odds ratios for factors found to significantly increase the risk of cage subsidence were; 1.950 (95% confidence interval, 1.002-4.224) for L5-S1 level, and 1.018 (95% confidence interval, 1.000-1.066) for anterior cage position. The rate of PEEK cage subsidence after MITLIF was relatively low. End-plate manipulation and cage insertion during MITLIF were not influenced by a small operation window.

  18. Fabrication of hydroxyapatite thin films on polyetheretherketone substrates using a sputtering technique.

    PubMed

    Ozeki, K; Masuzawa, T; Aoki, H

    2017-03-01

    Hydroxyapatite (HA) thin films were coated on a polyetheretherketone (PEEK) substrate using a sputtering technique. A thin titanium (Ti) intermediate layer was formed between the HA and the PEEK surface to improve adhesion of the HA film to the PEEK substrate. The coated films were recrystallized using a hydrothermal treatment to reduce the dissolution of the HA film. The films were then characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and a UV-Vis spectrophotometer. A pull-out test was performed to measure the film-to-substrate adhesion strength, and an immersion test was performed in ultra-pure water. In the XRD patterns of the sputtered film with the Ti intermediate layer on the PEEK substrate, small HA peaks and large Ti peaks were observed. After the hydrothermal treatment, the intensity of the HA peaks increased. The transmittance of the HA films with 5 and 10nm Ti intermediate layers was >79% and 68%, respectively, in the visible light wavelength region (400-700nm) after the hydrothermal treatment. The adhesion strength of the hydrothermally treated HA films increased with decreasing thickness of the Ti intermediate layer, and the strength reached 2.7MPa with the 5-nm-thick Ti intermediate layer. In the immersion test, the HA film with a 5-nm-thick Ti intermediate layer without hydrothermal treatment exhibited a released Ti concentration of 42.0±2.4ppb. After hydrothermal treatment, the released Ti concentration decreased to 17.3±1.1ppb.

  19. Response of Human Osteoblast to n-HA/PEEK--Quantitative Proteomic Study of Bio-effects of Nano-Hydroxyapatite Composite.

    PubMed

    Zhao, Minzhi; Li, Haiyun; Liu, Xiaochen; Wei, Jie; Ji, Jianguo; Yang, Shu; Hu, Zhiyuan; Wei, Shicheng

    2016-03-09

    Nano-sized hydroxyapatite (n-HA) is considered as a bio-active material, which is often mixed into bone implant material, polyetheretherketone (PEEK). To reveal the global protein expression modulations of osteoblast in response to direct contact with the PEEK composite containing high level (40%) nano-sized hydroxyapatite (n-HA/PEEK) and explain its comprehensive bio-effects, quantitative proteomic analysis was conducted on human osteoblast-like cells MG-63 cultured on n-HA/PEEK in comparison with pure PEEK. Results from quantitative proteomic analysis showed that the most enriched categories in the up-regulated proteins were related to calcium ion processes and associated functions while the most enriched categories in the down-regulated proteins were related to RNA process. This enhanced our understanding to the molecular mechanism of the promotion of the cell adhesion and differentiation with the inhibition of the cell proliferation on n-HA/PEEK composite. It also exhibited that although the calcium ion level of incubate environment hadn't increased, merely the calcium fixed on the surface of material had influence to intracellular calcium related processes, which was also reflect by the higher intracellular Ca(2+) concentration of n-HA/PEEK. This study could lead to more comprehensive cognition to the versatile biocompatibility of composite materials. It further proves that proteomics is useful in new bio-effect discovery.

  20. Influence of sulfur content on bone formation and antibacterial ability of sulfonated PEEK.

    PubMed

    Ouyang, Liping; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Li, Jinhua; Qiao, Yuqin; Ning, Congqin; Zhang, Xianlong; Chu, Paul K; Liu, Xuanyong

    2016-03-01

    Polyetheretherketone (PEEK) is desirable in orthopedic and dental applications because its mechanical properties are similar to those of natural bones but the bioinertness and inferior osteoconduction of PEEK have hampered many clinical applications. In this work, PEEK is sulfonated by concentrated sulfuric acid to fabricate a three-dimensional (3D) network. A hydrothermal treatment is subsequently conducted to remove the residues and the temperature is adjusted to obtain different sulfur concentrations. In vitro cell proliferation and real-time PCR analyses disclose enhanced proliferation and osteogenic differentiation of rat bone mesenchymal stem cells (rBMSCs) on the samples with small sulfur concentrations. The in vitro antibacterial evaluation reveals that all the sulfonated samples possess excellent resistance against Staphylococcus aureus and Escherichia coli. The in vivo rat femur implantation model is adopted and X-ray, micro-CT, and histological analyses indicate that not only the premeditated injected bacteria cells are sterilized, but also new bone forms around the samples with small sulfur concentrations. The in vitro and in vivo results reveal that the samples subjected to the hydrothermal treatment to remove excess sulfur have better osseointegration and antibacterial ability and PEEK modified by sulfonation and hydrothermal treatment is promising in orthopedic and dental applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. AgNPs-decorated 3D printed PEEK implant for infection control and bone repair.

    PubMed

    Deng, Lijun; Deng, Yi; Xie, Kenan

    2017-10-02

    Polyetheretherketone (PEEK) is an ideal substitute material for bone tissue engineering, which can avoid the stress shielding phenomenon due to its similar mechanical properties to natural human bone. Complex bone defect and postoperative infection are still two enormous challenges in orthopedic clinics. It's well-known that additive manufacturing possesses the merits of high-precision and rapid prototyping, thus it easily meets the needs of mold processing. In the present study, we developed a novel Ag-decorated 3D printed PEEK via catecholamine chemistry. SEM image showed that silver nanoparticles (AgNPs) were evenly anchored on the surface. The following antibacterial tests, including bacterial inhibition ring, bacterial dynamics curves and antibiofilm test, indicated that the Ag-decorated 3D PEEK scaffolds displayed significant antibacterial effect towards Gram-negative and Gram-positive bacteria. Then MG-63 cells were seeded on samples for cell proliferation and ALP activity tests. The results demonstrated the scaffold modified with AgNPs could support cell proliferation, and enhanced higher alkaline phosphatase activity compared with pure PEEK scaffold. Expectedly, this dual functional 3D material holds great potential application in clinical bone tissue repair. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Apatite-forming PEEK with TiO2 surface layer coating.

    PubMed

    Kizuki, Takashi; Matsushita, Tomiharu; Kokubo, Tadashi

    2015-01-01

    Polyetheretherketone (PEEK) is widely used in orthopedic implants, such as spinal fusion devices, because of its moderate elastic modulus, as well as relatively high mechanical strength. However, it does not bond to living bone, and hence it needs autograft to be fixed to the bone. In this study, we attempted to add bone-bonding properties to PEEK by coating with TiO2 synthesized by the sol-gel process. When a TiO2 sol solution consisting of titanium isopropoxide, water, ethanol, and nitric acid was deposited on a PEEK substrate without any pretreatment, the formed TiO2 gel layer was easily peeled off after subsequent treatments. However, when the same solution was deposited on PEEK that was preliminarily subjected to UV or O2 plasma treatment, the deposited TiO2 gel layer strongly adhered to the substrate even after subsequent treatments. The strong adhesion was attributed to the interaction among the C-O, C=O, and O-C=O groups on the PEEK owing to the UV or O2 plasma treatment and the Ti-O bond of the TiO2 gel. Apatite did not form on the as-formed TiO2 gel layer in a simulated body fluid (SBF) even within 3 days; however, apatite formed after soaking in 0.1 M HCl solution at 80 °C for 24 h. This apatite formation was attributed to positive surface charge of the TiO2 gel layer induced by the acid treatment. The PEEK with the TiO2 gel layer coating formed by the proposed process is expected to bond to living bone, because a positively charged titanium oxide which facilitates the formation of apatite in SBF within a short period is known to bond to living bone.

  3. Pressure behavior of different PEEK materials for dental implants.

    PubMed

    Schwitalla, Andreas Dominik; Spintig, Tobias; Kallage, Ilona; Müller, Wolf-Dieter

    2016-02-01

    Due to its mechanical properties, the biocompatible high-performance material PEEK (polyetheretherketone) and PEEK-based compounds may represent viable alternatives to titanium in the field of dental implantology. Therefore we performed static pressure tests with 11 PEEK materials (two unfilled grades, two grades filled with titanium-dioxide-powder, two grades filled with barium-sulfate-powder, two grades reinforced with short carbon fibers, one grade reinforced with glass fibers and two grades reinforced with continuous carbon fibers) in the form of cylindrical specimens with a diameter of 4, 5 and 6mm. The specimens had a height to diameter ratio of 2:1 and were therefore 8, 10 and 12mm high. The parameters elastic modulus, elastic limit and pressure strength were evaluated. The elastic moduli ranged between 2.65±0.03GPa for specimens of a titanium-dioxide-filled grade and 106.71±14.83GPa for specimens reinforced with continuous carbon fibers. The elastic limits ranged between 808.1±42.44N for specimens of a barium-sulfate-filled grade and 7256.4±519.86N for specimens reinforced with continuous carbon fibers. The lowest pressure strength of 122.77MPa was observed for specimens of an unfilled grade, whereas the highest pressure strength of 712.67±66.02MPa could be evaluated for specimens containing continuous carbon fibers. Regarding the maximum bite force of a first molar, all tested materials seem to be suitable for the use as dental implants.

  4. Comparison of the clinical and radiologic outcomes obtained with single- versus two-level anterior cervical decompression and fusion using stand-alone PEEK cages filled with allograft.

    PubMed

    Choi, Man Kyu; Kim, Sung Bum; Park, Chang Kyu; Kim, Sung Min

    2016-03-01

    Although anterior cervical decompression and fusion with a stand-alone cage (ACDF-SAC) is accepted as a suitable procedure, the outcomes of the multi-level procedure remain controversial. The aim of this study is to compare the clinical and radiologic outcomes achieved with single versus two-level ACDF-SAC along with identification of the factors that contribute to loss in mean disc height (MDH) and change in cervical lordotic angle (CLA). A total of 109 consecutive patients who underwent ACDF-SAC for degenerative spondylosis were reviewed. Patients were divided into two groups according to surgical level (group A, single; group B, two) and were followed for at least 1 year. Clinical outcomes were evaluated using the visual analog scale (VAS) and Robinson's criteria. The fusion and subsidence rates, MDH, CLA, anterior, and posterior vertebral body height of the fused segments (AVBH, PVBH) were measured retrospectively from plain radiographs. Clinical outcomes were similar in both groups, in terms of decreasing VAS score and a grade higher than "good" by Robinson's criteria. The fusion and subsidence rates for each group were found to be 92.2, 91.1, 14.1, and 20.0 %, respectively. The MDH (mm) increased by 1.44 ± 0.96 in group A, 1.57 ± 0.79 and 1.66 ± 0.69 for each surgical level in group B over the 12 postoperative months. The CLA (°) decreased by 1.70 ± 4.04 and 0.75 ± 6.12 over the 12 postoperative months from its presurgery value, the rate of kyphosis >5° was 26.6 and 22.2 % for each group. All compared values were not significantly different between the two groups. Correlation analysis revealed that the AVBH/PVBH ratio exhibited a positive correlation with CLA change in both groups (r = 0.368, 0.397; p = 0.018, 0.040). The overall outcomes achieved with two-level ACDF-SAC were similar to those achieved with single-level ones. In addition, the AVBH/PVBH ratio might be a predictable marker for a postoperative kyphosis.

  5. Microstructure and properties of composite polyetheretherketone/Bioglass® coatings deposited on Ti-6Al-7Nb alloy for medical applications

    NASA Astrophysics Data System (ADS)

    Moskalewicz, Tomasz; Seuss, Sigrid; Boccaccini, Aldo R.

    2013-05-01

    Composite polyetheretherketone (PEEK)/Bioglass® coatings were electrophoretically deposited on two phase α + β Ti-6Al-7Nb titanium alloy substrates. A heat treatment was performed to improve the adhesion of the coatings to the substrate. The microstructure of the coatings and substrate was examined by light microscopy, scanning- and transmission electron microscopy methods as well as by X-ray diffractometry. Coatings deposited from suspensions with PEEK/Bioglass® weight ratio of 0.3 showed the best quality. Coatings of 40 μm thickness, exhibiting uniform porosity, without any cracks or presence of large voids were produced. The microstructure of the coatings was observed to be composed of Bioglass® particles fairly homogeneously embedded in a PEEK matrix. STEM-EDX line analysis revealed diffusion of Na from the glass to the PEEK matrix after heat-treatment. The results demonstrate that electrophoretic deposition (EPD) is a very useful method to deposit uniform and reproducible microporous composite PEEK/Bioglass® coatings on titanium alloy substrate for biomedical applications.

  6. Novel surface modifications of carbon fiber-reinforced polyetheretherketone hip stem in an ovine model.

    PubMed

    Nakahara, Ichiro; Takao, Masaki; Bandoh, Shunichi; Bertollo, Nicky; Walsh, William R; Sugano, Nobuhiko

    2012-01-01

    A carbon fiber-reinforced polymer (CFRP) is theoretically a suitable material for use in an uncemented hip prosthesis considering it can provide isoelastic environment with the surrounding bone, adequate fatigue strength, and a metal-free radiographic evaluation. To date, the selection of polymer material and optimization of both design and surface finish of the prostheses for osseointegration has not been accomplished. This study examined radiographic and histologic results of an uncemented CFRP stem manufactured from carbon fiber-reinforced polyetheretherketone (CFR/PEEK) with a roughened surface and a bioactive treatment in an adult ovine model following a 12-month implantation period. A unilateral hemiarthroplasty of the hip was performed using the CFRP stem or a titanium stem as a control. Four cases with the CFRP stem and five cases with titanium stem were evaluated. Bone on-growth fixation was achieved in two cases with the CFRP stem and in all the cases with the titanium stem. The CFRP cases showed minimal stress shielding while three of five cases with the titanium stem demonstrated typical osteopenia associated with stiff metal stems. Bone on-growth to the uncemented CFRP stem was achieved by using the CFR/PEEK for the material and modifying the surface design and the bioactive surface finish. Bone resorption and osteopenia observed with the Ti stems was not found with the CFRP design.

  7. Plasma Surface Functionalized Polyetheretherketone for Enhanced Osseo-Integration at Bone-Implant Interface.

    PubMed

    Zhao, Ying; Wong, Hoi Man; Lui, So Ching; Chong, Eva Y W; Wu, Guosong; Zhao, Xiaoli; Wang, Chong; Pan, Haobo; Cheung, Kenneth M C; Wu, Shuilin; Chu, Paul K; Yeung, Kelvin W K

    2016-02-17

    This study aims at improving osseo-integration at the bone-implant interface of polyetheretherketone (PEEK) by water (H2O) and ammonia (NH3) plasma immersion ion implantation (PIII). The pertinent surface characteristics including surface energy, roughness, morphology, and chemical composition are investigated systematically and the in vitro biological performance is evaluated by cell adhesion and proliferation, alkaline phosphatase (ALP) activity, real-time RT-PCR evaluation, and mineralization tests. In vivo osseo-integration is examined via implanting samples into the distal femur of the rats. The hydrophilicity, surface roughness, cell adhesion, and proliferation, ALP activity, and osteogenic differentiation after H2O PIII or NH3 PIII are improved significantly. Furthermore, substantially enhanced osseo-integration is achieved in vivo. Nonline-of-sight plasma surface functionalization, which is particularly suitable for biomedical implants with an irregular geometry, does not alter the bulk compressive yield strength and elastic modulus of the materials. Consequently, the favorable bulk attributes of PEEK are preserved while the surface biological properties are enhanced thus boding well for wider orthopedic application of the biopolymer.

  8. Finite element analysis of the biomechanical effects of PEEK dental implants on the peri-implant bone.

    PubMed

    Schwitalla, A D; Abou-Emara, M; Spintig, T; Lackmann, J; Müller, W D

    2015-01-02

    Dental implants are mostly fabricated of titanium. Potential problems associated with these implants are discussed in the literature, for example, overloading of the jawbone during mastication due to the significant difference in the elastic moduli of titanium (110 GPa) and bone (≈1-30 GPa). Therefore poly-ether-ether-ketone (PEEK) could represent an alternative biomaterial (elastic modulus 3-4 GPa). Endolign(®) represents an implantable carbon fiber reinforced (CFR)-PEEK including parallel oriented endless carbon fibers. According to the manufacturer it has an elastic modulus of 150 GPa. PEEK compounds filled with powders show an elastic modulus around 4 GPa. The aim of the present finite element analysis was to point out the differences in the biomechanical behavior of a dental implant of Endolign(®) and a commercial powder-filled PEEK. Titanium served as control. These three materials were used for a platform-switched dental implant-abutment assembly, whereas Type 1 completely consisted of titanium, Type 2 of a powder-filled PEEK and Type 3 of Endolign(®). A force of 100 N was applied vertically and of 30° to the implant axis. All types showed a minimum safety factor regarding the yield strength of cortical bone. However, within the limits of this study the Type 2 implant showed higher stresses within the adjacent cortical bone than Type 1 and Type 3. These implant assemblies showed similar stress distributions. Endless carbon fibers give PEEK a high stability. Further investigations are necessary to evaluate whether there is a distinct amount of endless carbon fibers causing an optimal stress distribution behavior of CFR-PEEK. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. The long-term mechanical integrity of non-reinforced PEEK-OPTIMA polymer for demanding spinal applications: experimental and finite-element analysis.

    PubMed

    Ferguson, Stephen J; Visser, Judith M A; Polikeit, Anne

    2006-02-01

    Polyetheretherketone (PEEK) is a novel polymer with potential advantages for its use in demanding orthopaedic applications (e.g. intervertebral cages). However, the influence of a physiological environment on the mechanical stability of PEEK has not been reported. Furthermore, the suitability of the polymer for use in highly stressed spinal implants such as intervertebral cages has not been investigated. Therefore, a combined experimental and analytical study was performed to address these open questions. A quasi-static mechanical compression test was performed to compare the initial mechanical properties of PEEK-OPTIMA polymer in a dry, room-temperature and in an aqueous, 37 degrees C environment (n=10 per group). The creep behaviour of cylindrical PEEK polymer specimens (n=6) was measured in a simulated physiological environment at an applied stress level of 10 MPa for a loading duration of 2000 hours (12 weeks). To compare the biomechanical performance of different intervertebral cage types made from PEEK and titanium under complex loading conditions, a three-dimensional finite element model of a functional spinal unit was created. The elastic modulus of PEEK polymer specimens in a physiological environment was 1.8% lower than that of specimens tested at dry, room temperature conditions (P<0.001). The results from the creep test showed an average creep strain of less than 0.1% after 2000 hours of loading. The finite element analysis demonstrated high strain and stress concentrations at the bone/implant interface, emphasizing the importance of cage geometry for load distribution. The stress and strain maxima in the implants were well below the material strength limits of PEEK. In summary, the experimental results verified the mechanical stability of the PEEK-OPTIMA polymer in a simulated physiological environment, and over extended loading periods. Finite element analysis supported the use of PEEK-OPTIMA for load-bearing intervertebral implants.

  10. Preparation of three-dimensional braided carbon fiber-reinforced PEEK composites for potential load-bearing bone fixations. Part I. Mechanical properties and cytocompatibility.

    PubMed

    Luo, Honglin; Xiong, Guangyao; Yang, Zhiwei; Raman, Sudha R; Li, Qiuping; Ma, Chunying; Li, Deying; Wang, Zheren; Wan, Yizao

    2014-01-01

    In this study, we focused on fabrication and characterization of three-dimensional carbon fiber-reinforced polyetheretherketone (C3-D/PEEK) composites for orthopedic applications. We found that pre-heating of 3-D fabrics before hot-pressing could eliminate pores in the composites prepared by 3-D co-braiding and hot-pressing techniques. The manufacturing process and the processing variables were studied and optimum parameters were obtained. Moreover, the carbon fibers were surface treated by the anodic oxidization and its effect on mechanical properties of the composites was determined. Preliminary cell studies with mouse osteoblast cells were also performed to examine the cytocompatibility of the composites. Feasibility of the C3-D/PEEK composites as load-bearing bone fixation materials was evaluated. Results suggest that the C3-D/PEEK composites show good promising as load-bearing bone fixations.

  11. A nano-sandwich construct built with graphene nanosheets and carbon nanotubes enhances mechanical properties of hydroxyapatite–polyetheretherketone scaffolds

    PubMed Central

    Feng, Pei; Peng, Shuping; Wu, Ping; Gao, Chengde; Huang, Wei; Deng, Youwen; Xiao, Tao; Shuai, Cijun

    2016-01-01

    A nano-sandwich construct was built by combining two-dimensional graphene nanosheets (GNSs) and one-dimensional carbon nanotubes (CNTs) to improve the mechanical properties of hydroxyapatite–polyetheretherketone (HAP–PEEK) scaffolds for bone tissue engineering. In this nano-sandwich construct, the long tubular CNTs penetrated the interlayers of graphene and prevented their aggregation, increasing the effective contact area between the construct and matrix. The combination of GNSs and CNTs in a weight ratio of 2:8 facilitated the dispersion of each other and provided a synergetic effect in enhancing the mechanical properties. The compressive strength and modulus of the scaffolds were increased by 63.58% and 56.54% at this time compared with those of HAP–PEEK scaffolds, respectively. The carbon-based fillers, pulling out and bridging, were also clearly observed in the matrix. Moreover, the dangling of CNTs and their entangling with GNSs further reinforced the mechanical properties. Furthermore, apatite layer formed on the scaffold surface after immersing in simulated body fluid, and the cells attached and spread well on the surface of the scaffolds and displayed good viability, proliferation, and differentiation. These evidence indicate that the HAP–PEEK scaffolds enhanced by GNSs and CNTs are a promising alternative for bone tissue engineering. PMID:27555770

  12. Decreased bacteria activity on Si3N4 surfaces compared with PEEK or titanium

    PubMed Central

    Gorth, Deborah J; Puckett, Sabrina; Ercan, Batur; Webster, Thomas J; Rahaman, Mohamed; Bal, B Sonny

    2012-01-01

    A significant need exists for orthopedic implants that can intrinsically resist bacterial colonization. In this study, three biomaterials that are used in spinal implants – titanium (Ti), polyether-ether-ketone (PEEK), and silicon nitride (Si3N4) – were tested to understand their respective susceptibility to bacterial infection with Staphylococcus epidermidis, Staphlococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Enterococcus. Specifically, the surface chemistry, wettability, and nanostructured topography of respective biomaterials, and the effects on bacterial biofilm formation, colonization, and growth were investigated. Ti and PEEK were received with as-machined surfaces; both materials are hydrophobic, with net negative surface charges. Two surface finishes of Si3N4 were examined: as-fired and polished. In contrast to Ti and PEEK, the surface of Si3N4 is hydrophilic, with a net positive charge. A decreased biofilm formation was found, as well as fewer live bacteria on both the as-fired and polished Si3N4. These differences may reflect differential surface chemistry and surface nanostructure properties between the biomaterials tested. Because protein adsorption on material surfaces affects bacterial adhesion, the adsorption of fibronectin, vitronectin, and laminin on Ti, PEEK, and Si3N4 were also examined. Significantly greater amounts of these proteins adhered to Si3N4 than to Ti or PEEK. The findings of this study suggest that surface properties of biomaterials lead to differential adsorption of physiologic proteins, and that this phenomenon could explain the observed in-vitro differences in bacterial affinity for the respective biomaterials. Intrinsic biomaterial properties as they relate to resistance to bacterial colonization may reflect a novel strategy toward designing future orthopedic implants. PMID:22973102

  13. Mechanical property characterization and impact resistance of selected graphite/PEEK composite materials

    NASA Technical Reports Server (NTRS)

    Baker, Donald J.

    1994-01-01

    To use graphite polyetheretherketone (PEEK) material on highly curved surfaces requires that the material be drapable and easily conformable to the surface. This paper presents the mechanical property characterization and impact resistance results for laminates made from two types of graphite/PEEK materials that will conform to a curved surface. These laminates were made from two different material forms. These forms are: (1) a fabric where each yarn is a co-mingled Celion G30-500 3K graphite fiber and PEEK thermoplastic fiber; and (2) an interleaved material of Celion G30-500 3K graphite fabric interleaved with PEEK thermoplastic film. The experimental results from the fabric laminates are compared with results for laminates made from AS4/PEEK unidirectional tape. The results indicate that the tension and compression moduli for quasi-isotropic and orthotropic laminates made from fabric materials are at least 79 percent of the modulus of equivalent laminates made from tape material. The strength of fabric material laminates is at least 80 percent of laminates made from tape material. The evaluation of fabric material for shear stiffness indicates that a tape material laminate could be replaced by a fabric material laminate and still maintain 89 percent of the shear stiffness of the tape material laminate. The notched quasi-isotropic compression panel failure strength is 42 to 46 percent of the unnotched quasi-isotropic laminate strength. Damage area after impact with 20 ft-lbs of impact energy is larger for the co-mingled panels than for the interleaved panels. The inerleaved panels have less damage than panels made from tape material. Residual compression strength of quasi-isotropic panels after impact of 20 ft-lbs of energy varies between 33 percent of the undamaged quasi-isotropic material strength for the tape material and 38 percent of the undamaged quasi-isotropic material strength for the co-mingled fabric material.

  14. Applying the Mini-Open Anterolateral Lumbar Interbody Fusion with Self-Anchored Stand-Alone Polyetheretherketone Cage in Lumbar Revision Surgery

    PubMed Central

    Kuang, Lei; Chen, Yuqiao; Li, Lei; Lü, Guohua

    2016-01-01

    The author retrospectively studied twenty-two patients who underwent revision lumbar surgeries using ALLIF with a self-anchored stand-alone polyetheretherketone (PEEK) cage. The operation time, blood loss, and perioperative complications were evaluated. Oswestry disability index (ODI) scores and visual analog scale (VAS) scores of leg and back pain were analyzed preoperatively and at each time point of postoperative follow-up. Radiological evaluation including fusion, disc height, foraminal height, and subsidence was assessed. The results showed that the ALLIF with a self-anchored stand-alone PEEK cage is safe and effective in revision lumbar surgery with minor surgical trauma, low access-related complication rates, and satisfactory clinical and radiological results. PMID:27885355

  15. Properties and Corrosion Performance of Self-reinforced Composite PEEK for Proposed Use as a Modular Taper Gasket.

    PubMed

    Ouellette, Eric S; Gilbert, Jeremy L

    2016-11-01

    Fretting corrosion in medical alloys is a persistent problem, and the need for biomaterials that can effectively suppress mechanically assisted crevice corrosion in modular taper junctions or otherwise insulate metal-on-metal interfaces in mechanically demanding environments is as yet unmet. The purpose of this study is to characterize a novel material, self-reinforced composite polyetheretherketone (SRC-PEEK) and to evaluate its ability to inhibit fretting corrosion in a pin-on-disk metal-on-metal interface test. SRC-PEEK was fabricated by hot compaction of in-house-made PEEK fibers by compacting uniaxial layups at 344°C under a load of 18,000 N for 10 minutes. SRC-PEEK, bulk isotropic PEEK, and the in-house-made PEEK fibers were analyzed for thermal transitions (Tg, Tm) through differential scanning calorimetry, crystallinity, crystal size, crystalline orientation (Hermanns orientation parameter) through wide-angle x-ray scattering, and modulus, tensile strength, yield stress, and strain to failure through monotonic tensile testing. SRC-insulated pin-on-disk samples were compared with metal-on-metal control samples in pin-on-disk fretting corrosion experiments using fretting current and fretting mechanics measurements. Fifty-micron cyclic motion at 2.5 Hz was applied to the interface, first over a range of loads (0.5-35 N) while held at -0.05 V versus Ag/AgCl and then over a range of voltages (-0.5 to 0.5 V) at a constant contact stress of 73 ± 19 MPa for SRC-PEEK and 209 ± 41 MPa for metal-on-metal, which were different for each group as a result of changes in true contact area due to variations in modulus between sample groups. Pins, disks, and SRC samples were imaged for damage (on alloy and SRC surfaces) and evidence of corrosion (on alloy pin and disk surfaces). SRC specimens were analyzed for traces of alloy transferred to the surface using energy dispersive spectroscopy after pin-on-disk testing. SRC-PEEK showed improved mechanical properties to

  16. Electrophoretic Deposition, Microstructure, and Corrosion Resistance of Porous Sol-Gel Glass/Polyetheretherketone Coatings on the Ti-13Nb-13Zr Alloy

    NASA Astrophysics Data System (ADS)

    Moskalewicz, Tomasz; Zych, Anita; Łukaszczyk, Alicja; Cholewa-Kowalska, Katarzyna; Kruk, Adam; Dubiel, Beata; Radziszewska, Agnieszka; Berent, Katarzyna; Gajewska, Marta

    2017-05-01

    In this study, microporous composite sol-gel glass/polyetheretherketone (SGG/PEEK) coatings were produced on the Ti-13Nb-13Zr titanium alloy by electrophoretic deposition. Coatings with different levels of high open porosity were developed by introducing SGG particles of varying diameters into the PEEK matrix. The microstructure of the coatings was characterized by electron microscopy and X-ray diffractometry. The coatings with 40-50 µm thickness were composed of semicrystalline SGG particles consisting of hydroxyapatite, CaSiO3, some Ca2SiO4, and an amorphous phase containing Ca, Si, P, and O, homogeneously embedded in a semicrystalline PEEK matrix. The size of SGG particles present in the coatings strongly influenced the formation of microcracks and their adhesion to the underlying substrate. Microscratch tests showed that the coating containing SGG particles with a diameter smaller than 45 µm and open porosity of 45 pct exhibited good adhesion to the titanium alloy substrate, much better than the coating containing particles with a diameter smaller than 85 µm and total open porosity equal to 48 pct. The corrosion resistance was investigated in Ringer's solution at a temperature of 310 K (37 °C) for a pH equal to 7.4 and in deaerated solutions with the use of open-circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The SGG/PEEK-coated alloy indicated better electrochemical corrosion resistance compared with the uncoated alloy.

  17. Electrophoretic Deposition, Microstructure, and Corrosion Resistance of Porous Sol-Gel Glass/Polyetheretherketone Coatings on the Ti-13Nb-13Zr Alloy

    NASA Astrophysics Data System (ADS)

    Moskalewicz, Tomasz; Zych, Anita; Łukaszczyk, Alicja; Cholewa-Kowalska, Katarzyna; Kruk, Adam; Dubiel, Beata; Radziszewska, Agnieszka; Berent, Katarzyna; Gajewska, Marta

    2017-02-01

    In this study, microporous composite sol-gel glass/polyetheretherketone (SGG/PEEK) coatings were produced on the Ti-13Nb-13Zr titanium alloy by electrophoretic deposition. Coatings with different levels of high open porosity were developed by introducing SGG particles of varying diameters into the PEEK matrix. The microstructure of the coatings was characterized by electron microscopy and X-ray diffractometry. The coatings with 40-50 µm thickness were composed of semicrystalline SGG particles consisting of hydroxyapatite, CaSiO3, some Ca2SiO4, and an amorphous phase containing Ca, Si, P, and O, homogeneously embedded in a semicrystalline PEEK matrix. The size of SGG particles present in the coatings strongly influenced the formation of microcracks and their adhesion to the underlying substrate. Microscratch tests showed that the coating containing SGG particles with a diameter smaller than 45 µm and open porosity of 45 pct exhibited good adhesion to the titanium alloy substrate, much better than the coating containing particles with a diameter smaller than 85 µm and total open porosity equal to 48 pct. The corrosion resistance was investigated in Ringer's solution at a temperature of 310 K (37 °C) for a pH equal to 7.4 and in deaerated solutions with the use of open-circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy. The SGG/PEEK-coated alloy indicated better electrochemical corrosion resistance compared with the uncoated alloy.

  18. Evaluation of a PEEK titanium composite interbody spacer in an ovine lumbar interbody fusion model: a biomechanical, micro-computed tomography, and histologic analyses.

    PubMed

    McGilvray, Kirk C; Waldorff, Erik I; Easley, Jeremiah; Seim, Howard B; Zhang, Nianli; Linovitz, Raymond J; Ryaby, James T; Puttlitz, Christian M

    2017-07-24

    The most commonly used materials used for interbody cages are titanium metal and polymer polyetheretherketone (PEEK). Both of these materials have demonstrated good biocompatibility. A major disadvantage associated with solid titanium cages is their radiopacity, limiting post-operative monitoring of spinal fusion via standard imaging modalities. However, PEEK is radiolucent, allowing for temporal assessment of the fusion mass by clinicians. On the other hand, PEEK is hydrophobic, which can limit bony in-growth. While both PEEK and titanium have demonstrated clinical success in obtaining a solid spinal fusion, innovations are being developed in order to improve fusion rates and create stronger constructs using hybrid additive manufacturing approaches by incorporating both materials into a single interbody device. The purpose of this study was to examine the interbody fusion characteristic of a PEEK - titanium composite (PTC) cage for use in lumbar fusion. Thirty-four mature female sheep underwent two level (L2 - L3 and L4-L5) interbody fusion using either a PEEK or PTC cage (one of each per animal). Animals were sacrificed at 0, 8, 12 and 18-weeks post-surgery. Post-sacrifice, each surgically treated functional spinal unit underwent non-destructive kinematic testing, micro-CT scanning and histomorphometric analyses. Relative to the standard PEEK cages, the PTC constructs demonstrated significant reductions in ranges of motion and a significant increase in stiffness. These biomechanical findings were reinforced by the presence of significantly more bone at the fusion site as well as in-growth into the porous endplates. Overall, the results indicate that PTC interbody devices could potentially lead to a more robust intervertebral fusion relative to a standard PEEK device in a clinical setting. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  19. Spinal motion and intradiscal pressure measurements before and after lumbar spine instrumentation with titanium or PEEK rods.

    PubMed

    Abode-Iyamah, Kingsley; Kim, Sam Byeong; Grosland, Nicole; Kumar, Rajinder; Belirgen, Muhittin; Lim, Tae Hong; Torner, James; Hitchon, Patrick W

    2014-04-01

    Spinal instrumentation and fusion have been incriminated as contributing to adjacent segment degeneration (ASD). It has been suggested that ASD results from increased range of motion and intradiscal pressure (IDP) adjacent to instrumentation. Posterior dynamic stabilization with polyetheretherketone (PEEK) rods has been proposed as potentially advantageous compared to rigid instrumentation with titanium (Ti) rods in reducing the incidence of ASD. We evaluated segmental motions in the cadaveric spine instrumented with PEEK or Ti rods from L3 to S1, as well as the adjacent segment motions and IDP at L1-2 and L2-3. Human cadaveric spines were potted at T12-L1 and S1-2. Spinal instrumentation from L3-S1 was accomplished using pedicle screws with either PEEK or Ti rods. Specimens were subjected to displacement controlled testing: 15° flexion, 15° extension, 10° lateral bending, and 5° right axial rotation using the MTS machine (MTS, Minneapolis, MN, USA). Intradiscal pressure was measured by placing pressure transducers into the intervertebral disc at L1-2 and L2-3. Spinal motion of L2 relative to L3, and L3 relative to S1 was tracked using a three dimensional motion analysis system. Instrumentation with PEEK and Ti rods was associated with a decrease in L3-S1 motion compared to the intact state that was significant in flexion (p=0.002), and extension (p=0.0075). Instrumentation with PEEK and Ti rods was associated with an increase in IDP at L1-2 that was significant in flexion (p=0.0028). Instrumentation with either PEEK or Ti rods resulted in decreased motion at the instrumented levels while increasing IDP at the adjacent level. Published by Elsevier Ltd.

  20. Investigation and development of friction stir welding process for unreinforced polyphenylene sulfide and reinforced polyetheretherketone

    NASA Astrophysics Data System (ADS)

    Ahmed, Hossain

    The joining of thermoplastics through welding, a specific form of fusion bonding, offers numerous advantages over mechanical joining. It eliminates the use of costly fasteners and has only a limited effect on the strength of the parts being joined since it does not require the introduction of holes and loading pins, and it does not create significant stress concentrations. A specific form of welding, Friction Stir Welding, was investigated for the creation of butt joints of unreinforced polyphenylene sulfide (PPS) and short carbon fiber reinforced polyetheretherketone (PEEK) plates. Friction stir welding requires a rotating pin, a shoulder arrangement, relative movement between the tool and the weld piece and a clamping mechanism to hold the weld piece in place. Analytical models and experimental results show that the heat generated by the FSW tool is insufficient to produce the heat required to weld thermoplastic materials which makes FSW of polymers different from FSW of metals. A second heat source is required for preheating the thermoplastic parts prior to welding. A resistance type surface heater was placed at the bottom of two identical weld pieces for the experiments. Two types of shoulder design i.e. a rotating shoulder and a stationary shoulder were developed. Taguchi's Design of Experiment method was utilized to investigate the welding process, where duration of heating, process temperature, tool rotational speed and tool traverse speed were used as the welding parameters. The quality of the welding process was assumed to be indicated by the weld strength. DoE revealed that one of the process parameters, tool traverse speed, had significant influence on the tensile strength of PPS samples. While PPS sample showed relatively lower tensile strength with higher traverse speed, short carbon fiber reinforced PEEK samples had higher tensile strength with higher traverse speeds. In addition to tensile tests on dog bone shaped specimen, fracture toughness tests

  1. Surface properties of polyetheretherketone after different laboratory and chairside polishing protocols.

    PubMed

    Heimer, Sina; Schmidlin, Patrick R; Roos, Malgorzata; Stawarczyk, Bogna

    2017-03-01

    Polyetheretherketone (PEEK) can be used as a framework material for fixed dental prostheses. However, information about laboratory and chairside polishing methods is still scarce. The purpose of this in vitro study was to determine the effects of laboratory and chairside polishing methods on the surface roughness (SR) and surface free energy (SFE) of PEEK, an autopolymerizing poly(methyl methacrylate), and a veneering composite resin. For each of the 3 materials, 80 specimens were prepared (N=240) and divided into 7 polishing groups and 1 control group (n=10). The 7 groups were split into 4 laboratory protocols: polishing paste (Abraso), a second polishing paste (Opal L), silicone polisher (Ceragum), and diamond grinder (Diagen-Turbo grinder). The other 3 groups were chairside protocols: rainbow technique (Super-Snap kit), polishing paste (Prisma gloss), and a polishing system (Enhance finishing). Machine polishing with SiC P4000 served as the control treatment. The protocols' average SRs and SFEs were measured, and their surface topographies were evaluated with scanning electron microscopy (SEM). The logarithmically transformed data were analyzed using covariance analysis, 2-way and 1-way ANOVA, and partial correlation (α=.05). The polishing protocol exerted the highest influence on SR and SFE values (P<.001; SR: partial eta squared ηP(2)=.970; SFE: ηP(2)=.450), followed by material group (P<.001, SR: ηP(2)=.319; SFE: ηP(2)=.429). The interaction effect of the binary combinations of the 2 independent parameters (polishing protocol and material group) was also significant (P<.001, SR: ηP(2)=.681; SFE: ηP(2)=.365). Chairside methods presented lower SR values than laboratory methods, and specimens polished using the 2-body mode showed higher SR than did specimens polished using the 3-body mode. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  2. Patient-specific polyetheretherketone facial implants in a computer-aided planning workflow.

    PubMed

    Guevara-Rojas, Godoberto; Figl, Michael; Schicho, Kurt; Seemann, Rudolf; Traxler, Hannes; Vacariu, Apostolos; Carbon, Claus-Christian; Ewers, Rolf; Watzinger, Franz

    2014-09-01

    In the present study, we report an innovative workflow using polyetheretherketone (PEEK) patient-specific implants for esthetic corrections in the facial region through onlay grafting. The planning includes implant design according to virtual osteotomy and generation of a subtraction volume. The implant design was refined by stepwise changing the implant geometry according to soft tissue simulations. One patient was scanned using computed tomography. PEEK implants were interactively designed and manufactured using rapid prototyping techniques. Positioning intraoperatively was assisted by computer-aided navigation. Two months after surgery, a 3-dimensional surface model of the patient's face was generated using photogrammetry. Finally, the Hausdorff distance calculation was used to quantify the overall error, encompassing the failures in soft tissue simulation and implantation. The implant positioning process during surgery was satisfactory. The simulated soft tissue surface and the photogrammetry scan of the patient showed a high correspondence, especially where the skin covered the implants. The mean total error (Hausdorff distance) was 0.81 ± 1.00 mm (median 0.48, interquartile range 1.11). The spatial deviation remained less than 0.7 mm for the vast majority of points. The proposed workflow provides a complete computer-aided design, computer-aided manufacturing, and computer-aided surgery chain for implant design, allowing for soft tissue simulation, fabrication of patient-specific implants, and image-guided surgery to position the implants. Much of the surgical complexity resulting from osteotomies of the zygoma, chin, or mandibular angle might be transferred into the planning phase of patient-specific implants. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  3. Iliac crest autograft versus alternative constructs for anterior cervical spine surgery: Pros, cons, and costs

    PubMed Central

    Epstein, Nancy E.

    2012-01-01

    Background: Grafting choices available for performing anterior cervical diskectomy/fusion (ACDF) procedures have become a major concern for spinal surgeons, and their institutions. The “gold standard”, iliac crest autograft, may still be the best and least expensive grafting option; it deserves to be reassessed along with the pros, cons, and costs for alternative grafts/spacers. Methods: Although single or multilevel ACDF have utilized iliac crest autograft for decades, the implant industry now offers multiple alternative grafting and spacer devices; (allografts, cages, polyether-etherketone (PEEK) amongst others). While most studies have focused on fusion rates and clinical outcomes following ACDF, few have analyzed the “value-added” of these various constructs (e.g. safety/efficacy, risks/complications, costs). Results: The majority of studies document 95%-100% fusion rates when iliac crest autograft is utilized to perform single level ACDF (X-ray or CT confirmed at 6-12 postoperative months). Although many allograft studies similarly quote 90%-100% fusion rates (X-ray alone confirmed at 6-12 postoperative months), a recent “post hoc analysis of data from a prospective multicenter trial” (Riew KD et. al., CSRS Abstract Dec. 2011; unpublished) revealed a much higher delayed fusion rate using allografts at one year 55.7%, 2 years 87%, and four years 92%. Conclusion: Iliac crest autograft utilized for single or multilevel ACDF is associated with the highest fusion, lowest complication rates, and significantly lower costs compared with allograft, cages, PEEK, or other grafts. As spinal surgeons and institutions become more cost conscious, we will have to account for the “value added” of these increasingly expensive graft constructs. PMID:22905321

  4. A modified CDC biofilm reactor to produce mature biofilms on the surface of peek membranes for an in vivo animal model application.

    PubMed

    Williams, Dustin L; Woodbury, Kassie L; Haymond, Bryan S; Parker, Albert E; Bloebaum, Roy D

    2011-06-01

    Biofilm-related infections have become a major clinical concern. Typically, animal models that involve inoculation with planktonic bacteria have been used to create positive infection signals and examine antimicrobial strategies for eradicating or preventing biofilm-related infection. However, it is estimated that 99.9% of bacteria in nature dwell in established biofilms. As such, open wounds have significant potential to become contaminated with bacteria that reside in a well-established biofilm. In this study, a modified CDC biofilm reactor was developed to repeatably grow mature biofilms of Staphylococcus aureus on the surface of polyetheretherketone (PEEK) membranes for inoculation in a future animal model of orthopaedic implant biofilm-related infection. Results indicated that uniform, mature biofilms repeatably grew on the surface of the PEEK membranes.

  5. Antibacterial polyetheretherketone implants immobilized with silver ions based on chelate-bonding ability of inositol phosphate: processing, material characterization, cytotoxicity, and antibacterial properties.

    PubMed

    Kakinuma, H; Ishii, K; Ishihama, H; Honda, M; Toyama, Y; Matsumoto, M; Aizawa, M

    2015-01-01

    We developed a novel antibacterial implant by forming a hydroxyapatite (HAp) film on polyetheretherketone (PEEK) substrate, and then immobilizing silver ions (Ag(+) ) on the HAp film based on the chelate-bonding ability of inositol phosphate (IP6). First, the PEEK surface was modified by immersion into concentrated sulfuric acid for 10 min. HAp film was formed on the acid-treated PEEK via the soft-solution process using simulated body fluid (SBF), urea, and urease. After HAp coating, specimens were immersed into IP6 solution, and followed by immersion into silver nitrite solution at concentrations of 0, 0.5, 1, 5 or 10 mM. Ag(+) ions were immobilized on the resulting HAp film due to the chelate-bonding ability of IP6. On cell-culture tests under indirect conditions by Transwell, MC3T3-E1 cells on the specimens derived from the 0.5 and 1 mM Ag(+) solutions showed high relative growth when compared with controls. Furthermore, on evaluation of antibacterial activity in halo test, elution of Ag(+) ions from Ag(+) -immobilized HAp film inhibited bacterial growth. Therefore, the above-mentioned results demonstrated that specimens had both biocompatibility and strong antibacterial activity. The present coating therefore provides bone bonding ability to the implant surface and prevents the formation of biofilms in the early postoperative period.

  6. The wear properties of CFR-PEEK-OPTIMA articulating against ceramic assessed on a multidirectional pin-on-plate machine.

    PubMed

    Scholes, S C; Unsworth, A

    2007-04-01

    In an attempt to prolong the lives of rubbing implantable devices, several 'new' materials have been examined to determine their suitability as joint couplings. Tests were performed on a multidirectional pin-on-plate machine to determine the wear of both pitch and PAN (polyacrylonitrile)-based carbon fibre reinforced-polyetheretherketone (CFR-PEEK-OPTIMA) pins articulating against both BioLox Delta and BioLox Forte plates (ceramic materials). Both reciprocation and rotational motion were applied to the samples. The tests were conducted using 24.5 per cent bovine serum as the lubricant (protein concentration 15 g/l). Although all four material combinations gave similar low wear with no statistically significant difference (p > 0.25), the lowest average total wear of these pin-on-plate tests was provided by CFR-PEEK-OPTIMA pitch pins versus BioLox Forte plates. This was much lower than the wear produced by conventional joint materials (metal-on-polyethylene) and metal-on-metal combinations when tested on the pin-on-plate machine. This therefore indicates optimism that these PEEK-OPTIMA-based material combinations may perform well in joint applications.

  7. A Sustainable Evaluation of Drilling Parameters for PEEK-GF30

    PubMed Central

    Domingo, Rosario; García, Manuel; Sánchez, Alberto; Gómez, Rosa

    2013-01-01

    This paper presents a study of hole quality and energy consumption in the process of drilling a thermoplastic polymeric material, polyether-ether-ketone, reinforced with 30% glass fibers (PEEK-GF30). PEEK-GF30’s capacity to be machined has focused on turning operations. Studies of drilling involving thermoplastic polymeric materials have considered materials with other types of matrices, or reinforcement. In this study, quantities such as maximum and mean surface roughness, delamination, maximum thrust force, maximum momentum, and energy required during the process were determined for three types of drill bits, and the most influential factors for each variable were identified using an ANOVA multifactor analysis. The highest quality and lowest energy consumption were achieved for a drill bit rotation speed of 7000 rpm and a feed rate of 400 mm/min with a tungsten carbide (WC) drill bit coated with titanium aluminum nitride (TiAlN). Although a WC drill bit with a diamond point reduces delamination, the roughness increases, thus, the choice of the drill bit type depends on the roughness allowed. A WC drill bit coated with TiAlN produces a good surface finish that can eliminate subsequent operations and requires less energy; thus, this type of drill bit is the most attractive of the types evaluated. PMID:28788429

  8. Macrophage reactivity to different polymers demonstrates particle size- and material-specific reactivity: PEEK-OPTIMA(®) particles versus UHMWPE particles in the submicron, micron, and 10 micron size ranges.

    PubMed

    Hallab, Nadim James; McAllister, Kyron; Brady, Mark; Jarman-Smith, Marcus

    2012-02-01

    Biologic reactivity to orthopedic implant debris is generally the main determinant of long-term clinical performance where released polymeric particles of Ultra-high molecular weight polyethylene (UHMWPE) remain the most prevalent debris generated from metal-on-polymer bearing total joint arthroplasties. Polymeric alternatives to UHMWPE such as polyetherether-ketone (PEEK) may have increased wear resistance but the bioreactivity of PEEK-OPTIMA particles on peri-implant inflammation remains largely uncharacterized. We evaluated human monocyte/macrophage responses (THP-1s and primary human) when challenged by PEEK-OPTIMA, UHMWPE, and X-UHMWPE particles of three particle sizes (0.7 um, 2 um, and 10 um) at a dose of 20 particles-per-cell at 24- and 48-h time points. Macrophage responses were measured using cytotoxicity assays, viability assays, proliferation assays and cytokine analysis (IL-1b, IL-6, IL-8, MCP-1, and TNF-α). In general, there were no significant differences between PEEK-OPTIMA, UHMWPE, and X-UHMWPE particles on macrophage viability or proliferation. However, macrophages demonstrated greater cytotoxicity responses to UHMWPE and X-UHMWPE than to PEEK-OPTIMA at 24 and 48 h, where 0.7 μm-UHMWPE particles produced the highest amount of cytotoxicity. Particles of X-UHMWPE more than PEEK-OPTIMA and UHMWPE induced IL-1β, IL-6, MCP-1, and TNF-α at 24 h, p < 0.05 (no significant differences at 48 h). On average, cytokine production was more adversely affected by larger 10 μm particles than by 0.7 and 2 μm sized particles. While limitations of in vitro analysis apply to this study, PEEK-OPTIMA particles were more biocompatible than UHMWPE particles, in that they induced less inflammatory cytokine responses and thus, in part, demonstrates that PEEK-OPTIMA implant debris does not represent an increased inflammatory risk over that of UHMWPE.

  9. Assessment of a polyelectrolyte multilayer film coating loaded with BMP-2 on titanium and PEEK implants in the rabbit femoral condyle

    PubMed Central

    Guillot, R.; Pignot-Paintrand, I.; Lavaud, J.; Decambron, A.; Bourgeois, E.; Josserand, V.; Logeart-Avramoglou, D.; Viguier, E.; Picart, C.

    2016-01-01

    The aim of this study was to evaluate the osseointegration of titanium implants (Ti-6Al-4V, noted here TA6V) and poly(etheretherketone) PEEK implants induced by a BMP-2-delivering surface coating made of polyelectrolyte multilayer films. The in vitro bioactivity of the polyelectrolyte film-coated implants was assessed using the alkaline phosphatase assay. BMP-2-coated TA6V and PEEK implants with a total dose of 9.3 µg of BMP-2 were inserted into the femoral condyles of New Zealand white rabbits and compared to uncoated implants. Rabbits were sacrificed 4 and 8 weeks after implantation. Histomorphometric analyses on TA6V and PEEK implants and microcomputed tomography on PEEK implants revealed that the bone-to-implant contact and bone area around the implants were significantly lower for the BMP-2-coated implants than for the bare implants. This was confirmed by scanning electron microscopy imaging. This difference was more pronounced at 4 weeks in comparison to the 8-week time point. However, bone growth inside the hexagonal upper hollow cavity of the screws was higher in the case of the BMP-2 coated implants. Overall, this study shows that a high dose of BMP-2 leads to localized and temporary bone impairment, and that the dose of BMP-2 delivered at the surface of an implant needs to be carefully optimized. PMID:26965394

  10. Cervicitis

    MedlinePlus

    ... growth of normal bacteria in the vagina (bacterial vaginosis) can also cause cervicitis. ... a microscope (may show candidiasis , trichomoniasis , or bacterial vaginosis) Pap test Tests for gonorrhea or chlamydia Rarely, ...

  11. Characterization of PEEK, PET and PI implanted with Mn ions and sub-sequently annealed

    NASA Astrophysics Data System (ADS)

    Mackova, A.; Malinsky, P.; Miksova, R.; Pupikova, H.; Khaibullin, R. I.; Slepicka, P.; Gombitová, A.; Kovacik, L.; Svorcik, V.; Matousek, J.

    2014-04-01

    Polyimide (PI), polyetheretherketone (PEEK) and polyethylene terephthalate (PET) foils were implanted with 80 keV Mn+ ions at room temperature at fluencies of 1.0 × 1015-1.0 × 1016 cm-2. Mn depth profiles determined by RBS were compared to SRIM 2012 and TRIDYN simulations. The processes taking place in implanted polymers under the annealing procedure were followed. The measured projected ranges RP differ slightly from the SRIM and TRIDYN simulation and the depth profiles are significantly broader (up to 2.4 times) than those simulated by SRIM, while TRIDYN simulations were in a reasonable agreement up to the fluence 0.5 × 1016 in PEEK. Oxygen and hydrogen escape from the implanted layer was examined using RBS and ERDA techniques. PET, PEEK and PI polymers exhibit oxygen depletion up to about 40% of its content in virgin polymers. The compositional changes induced by implantation to particular ion fluence are similar for all polymers examined. After annealing no significant changes of Mn depth distribution was observed even the further oxygen and hydrogen desorption from modified layers appeared. The surface morphology of implanted polymers was characterized using AFM. The most significant change in the surface roughness was observed on PEEK. Implanted Mn atoms tend to dissipate in the polymer matrix, but the Mn nanoparticles are too small to be observed on TEM micrographs. The electrical, optical and structural properties of the implanted and sub-sequently annealed polymers were investigated by sheet resistance measurement and UV-Vis spectroscopy. With increasing ion fluence, the sheet resistance decreases and UV-Vis absorbance increases simultaneously with the decline of optical band gap Eg. The most pronounced change in the resistance was found on PEEK. XPS spectroscopy shows that Mn appears as a mixture of Mn oxides. Mn metal component is not present. All results were discussed in comparison with implantation experiment using the various ion species (Ni, Co

  12. PEEK versus titanium locking plates for proximal humerus fracture fixation: a comparative biomechanical study in two- and three-part fractures.

    PubMed

    Schliemann, Benedikt; Seifert, Robert; Theisen, Christina; Gehweiler, Dominic; Wähnert, Dirk; Schulze, Martin; Raschke, Michael J; Weimann, Andre

    2017-01-01

    The high rigidity of metal implants may be a cause of failure after fixation of proximal humerus fractures. Carbon fiber-reinforced polyetheretherketone (PEEK) plates with a modulus similar to human cortical bone may help to overcome this problem. The present study assesses the biomechanical behavior of a PEEK plate compared with a titanium locking plate. Unstable two- and three-part fractures were simulated in 12 pairs of cadaveric humeri and were fixed with either a PEEK or a titanium locking plate using a pairwise comparison. With an optical motion capture system, the stiffness, failure load, plate bending, and the relative motion at the bone-implant interface and at the fracture site were evaluated. The mean load to failure for two- and three-part fracture fixations was, respectively, 191 N (range 102-356 N) and 142 N (range 102-169 N) in the PEEK plate group compared with 286 N (range 191-395 N) and 258 N (range 155-366 N) in the titanium locking plate group. The PEEK plate showed significantly more bending in both the two- and three-part fractures (p < 0.05), an increased relative motion at the bone-implant interface and lower stiffness values (p < 0.05). In this biomechanical study on unstable proximal humerus fractures, fixation with a PEEK plate showed lower fixation strength and increased motion at the bone-implant interface compared with a titanium locking plate.

  13. The effect of different surface treatments on the bond strength of PEEK composite materials.

    PubMed

    Zhou, Li; Qian, Yuetong; Zhu, Ye; Liu, Hong; Gan, Kang; Guo, Jing

    2014-08-01

    To evaluate the effect of different surface treatments on the bond strength between polyetheretherketone (PEEK) composite materials and each of two different luting cements. One hundred specimens were randomly divided into five groups (n=20/group) as follows: (A) no treatment, (B) 98% sulfuric acid, (C) 9.5% hydrofluoric acid, (D) argon plasma treatment, and (E) sandblast with 50μm Al2O3 particles. Each group was divided into two subgroups of different cements: RelyX™ Unicem and SE Bond/Clearfil AP-X™. The cements were bonded onto the specimens. All specimens were stored in distilled water at 37° for 24h. Bond strength was measured in a shear test, and failure modes were assessed by stereomicroscopy. The surfaces were observed by SEM after the different pretreatments. Etching with 98% sulfuric acid and argon plasma treatment can significantly enforce the bond strength of RelyX™ Unicem or SE Bond/Clearfil AP-X™ to PEEK composite materials in comparison to the group of no treatment, hydrofluoric acid or sandblasting (p<0.05). No adhesion was established on the groups of no treatment and hydrofluoric acid when RelyX™ Unicem was used. Applying the SE Bond/Clearfil AP-X™ system, no statistical differences were found whether hydrofluoric acid was applied or not (p>0.05). The shear bond strength value of using SE Bond/Clearfil AP-X™ was higher than that of using RelyX™ Unicem with the same surface conditioning method (p<0.05). The use of SE Bond/Clearfil AP-X™ after the surface of PEEK composite material treated with sulfuric acid or argon plasma can be recommended as an effective bonding method. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  14. Cervicitis

    MedlinePlus

    ... uterine lining and the fallopian tubes, resulting in pelvic inflammatory disease (PID), an infection of the female reproductive organs that can cause fertility problems if left untreated. Cervicitis can also ... incidentally during a routine pelvic exam and Pap test and may not require ...

  15. Adjacent-Level Hypermobility and Instrumented-Level Fatigue Loosening With Titanium and PEEK Rods for a Pedicle Screw System: An In Vitro Study.

    PubMed

    Agarwal, Aakas; Ingels, Marcel; Kodigudla, Manoj; Momeni, Narjes; Goel, Vijay; Agarwal, Anand K

    2016-05-01

    Adjacent-level disease is a common iatrogenic complication seen among patients undergoing spinal fusion for low back pain. This is attributed to the postsurgical differences in stiffness between the spinal levels, which result in abnormal forces, stress shielding, and hypermobility at the adjacent levels. In addition, as most patients undergoing these surgeries are osteoporotic, screw loosening at the index level is a complication that commonly accompanies adjacent-level disease. Recent studies indicate that a rod with lower rigidity than that of titanium may help to overcome these detrimental effects at the adjacent level. The present study was conducted in vitro using 12 L1-S1 specimens divided into groups of six, with each group instrumented with either titanium rods or PEEK (polyetheretherketone) rods. The test protocol included subjecting intact specimens to pure moments of 10 Nm in extension and flexion using an FS20 Biomechanical Spine Test System (Applied Test Systems) followed by hybrid moments on the instrumented specimens to achieve the same L1-S1 motion as that of the intact specimens. During the protocol's later phase, the L4-L5 units from each specimen were segmented for cyclic loading followed by postfatigue kinematic analysis to highlight the differences in motion pre- and postfatigue. The objectives included the in vitro comparison of (1) the adjacent-level motion before and after instrumentation with PEEK and titanium rods and (2) the pre- and postfatigue motion at the instrumented level with PEEK and titanium rods. The results showed that the adjacent levels above the instrumentation caused increased flexion and extension with both PEEK and titanium rods. The postfatigue kinematic data showed that the motion at the instrumented level (L4-L5) increased significantly in both flexion and extension compared to prefatigue motion in titanium groups. However, there was no significant difference in motion between the pre- and postfatigue data in the PEEK

  16. Distal radius plate of CFR-PEEK has minimal effect compared to titanium plates on bone parameters in high-resolution peripheral quantitative computed tomography: a pilot study.

    PubMed

    de Jong, Joost J A; Lataster, Arno; van Rietbergen, Bert; Arts, Jacobus J; Geusens, Piet P; van den Bergh, Joop P W; Willems, Paul C

    2017-02-27

    Carbon-fiber-reinforced poly-ether-ether-ketone (CFR-PEEK) has superior radiolucency compared to other orthopedic implant materials, e.g. titanium or stainless steel, thus allowing metal-artifact-free postoperative monitoring by computed tomography (CT). Recently, high-resolution peripheral quantitative CT (HRpQCT) proved to be a promising technique to monitor the recovery of volumetric bone mineral density (vBMD), micro-architecture and biomechanical parameters in stable conservatively treated distal radius fractures. When using HRpQCT to monitor unstable distal radius fractures that require volar distal radius plating for fixation, radiolucent CFR-PEEK plates may be a better alternative to currently used titanium plates to allow for reliable assessment. In this pilot study, we assessed the effect of a volar distal radius plate made from CFR-PEEK on bone parameters obtained from HRpQCT in comparison to two titanium plates. Plates were instrumented in separate cadaveric human fore-arms (n = 3). After instrumentation and after removal of the plates duplicate HRpQCT scans were made of the region covered by the plate. HRpQCT images were visually checked for artifacts. vBMD, micro-architectural and biomechanical parameters were calculated, and compared between the uninstrumented and instrumented radii. No visible image artifacts were observed in the CFR-PEEK plate instrumented radius, and errors in bone parameters ranged from -3.2 to 2.6%. In the radii instrumented with the titanium plates, severe image artifacts were observed and errors in bone parameters ranged between -30.2 and 67.0%. We recommend using CFR-PEEK plates in longitudinal in vivo studies that monitor the healing process of unstable distal radius fractures treated operatively by plating or bone graft ingrowth.

  17. PEEK Primary Crowns with Cobalt-Chromium, Zirconia and Galvanic Secondary Crowns with Different Tapers—A Comparison of Retention Forces

    PubMed Central

    Stock, Veronika; Schmidlin, Patrick R.; Merk, Susanne; Wagner, Christina; Roos, Malgorzata; Eichberger, Marlis; Stawarczyk, Bogna

    2016-01-01

    In prosthetic dentistry, double crown systems have proved their suitability as retainers for removable partial dentures. However, investigations in this context, regarding polyetheretherketone, are scarce. Therefore, the aim of this study was to test the retention force (RF) between polyetheretherketone (PEEK) primary and cobalt-chromium (CoCr), zirconia (ZrO2) and galvanic (GAL) secondary crowns with three different tapers. Primary PEEK-crowns were milled with the tapers 0°, 1°, and 2° (n = 10/taper, respectively). Afterwards, 90 secondary crowns were fabricated: (i) 30 CoCr-crowns milled from Ceramill Sintron (AmannGirrbach, Koblach, Austria) (n = 10/taper), (ii) 30 ZrO2-crowns milled from Ceramill ZI (AmannGirrbach, Koblach, Austria) (n = 10/taper), and (iii) 30 GAL-crowns made using electroforming (n = 10/taper). RF was measured in a pull-off test (20 pull-offs/specimen) and data were analyzed using 2-/1-way Analysis of Variance (ANOVA) followed by the Tukey-Honestly Significant Difference (HSD) post hoc test and linear regression analyses (p < 0.05). The measured mean RF values ranged between 9.6 and 38.2 N. With regard to the 0°, 1°, and 2° tapered crowns, no statistically significant differences between CoCr and ZrO2 were observed (p > 0.141). At 0° taper, no differences in retention forces between GAL, CrCr, and ZrO2 crowns were found (p = 0.075). However, at 1° and 2° taper, lower RF for GAL-crowns were observed (p < 0.009, p < 0.001, respectively). According to this laboratory study, PEEK might be a suitable material for primary crowns, regardless of the taper and the material of secondary crown. Long-term results, however, are still necessary. PMID:28773311

  18. Mechanical strength of additive manufactured carbon fiber reinforced polyetheretherketone

    NASA Astrophysics Data System (ADS)

    Chumaevskii, A. V.; Tarasov, S. Yu.; Filippov, A. V.; Kolubaev, E. A.; Rubtsov, V. E.; Eliseev, A. A.

    2016-11-01

    Mechanical properties of both pure and chopped carbon fiber reinforced polyetheretherketone samples have been carried out. It was shown that the reinforcement resulted in increasing the elasticity modulus, compression and tensile ultimate strength by a factor of 3.5, 2.9 and 2.8, respectively. The fracture surfaces have been examined using both optical and scanning electron microscopy.

  19. The influence of metal artifacts on navigation and the reduction of artifacts by the use of polyether-ether-ketone.

    PubMed

    Citak, M; Kendoff, D; Wanich, T; Look, V; Stuber, V; Geerling, J; Krettek, C; Hüfner, T

    2008-07-01

    Registration is a crucial step in navigation assisted surgery. When performing anatomical pair-point registration, there are several potential sources of error, including inadequate data acquisition, improper segmentation, and distortion resulting from metal artifacts. The aim of this study was to evaluate the influence of metal artifacts on the precision of Iso-C(3D) and fluoroscopy-based navigation, and to assess any changes in precision from the use of a newly developed Schanz screw composed of polyether-ether-ketone (PEEK OPTIMA). A T-shaped test specimen was manufactured from synthetic bone material. It was then scanned with a Siremobil Iso-C(3D) while different types of implant were present in the specimen. Five Iso-C(3D) scans were acquired: one with a steel Schanz screw in the specimen, one with a titanium screw, one with a PEEK screw, one with a 5-hole plate, and one with no screw or plate present. The registration was analyzed by "reverse verification" with a pointer in a purpose-built, manipulable 3D holder. All experiments were then repeated using fluoroscopy-based navigation. Increasing presence of metal in the scan area resulted in an increase in mean error (0.55 mm with the steel Schanz screw, 0.7 mm with the 5-hole plate). Artifacts resulting from the titanium Schanz screw were less than those caused by the stainless steel Schanz screw. While this study demonstrates that metallic artifacts do have an influence on the precision of Iso-C(3D) navigation, such artifacts were not found to be a factor when performing fluoroscopy-based navigation.

  20. A rare case of pharyngeal perforation and expectoration of an entire anterior cervical fixation construct.

    PubMed

    Quadri, Syed A; Capua, John; Ramakrishnan, Vivek; Sweiss, Raed; Cabanne, Marc; Noel, Jerry; Fiani, Brian; Siddiqi, Javed

    2017-02-03

    Anterior cervical discectomy and fusion (ACDF) is a very common surgery performed globally. Although a few cases of expectorating screws or extrusion of screws into the gastrointestinal tract through esophageal perforations have previously been reported, there has not been a case reporting pharyngeal perforation and entire cervical construct extrusion in the literature to date. In this report the authors present the first case involving the extrusion of an entire cervical construct via a tear in the posterior pharyngeal wall. An 81-year-old woman presented to the emergency department (ED) with a complaint of significant cervical pain 5 days after a fall due to a syncopal event. Radiological findings showed severe anterior subluxation of C-2 on C-3 with no spinal cord signal change noted. She underwent ACDF at the C2-3 level utilizing a polyetheretherketone (PEEK) cage, allograft, autograft, and a nontranslational plate with a locking apparatus and expanding screws. The screw placement was satisfactory on postoperative radiography and the Grade II spondylolisthesis of C-2 on C-3 was reduced appropriately with the surgery. The postoperative radiographs obtained demonstrated good instrumentation placement. Three and a half years later the patient returned to the ED having expectorated the entire anterior cervical construct. A CT scan demonstrated the C-2 and C-3 vertebral bodies to be fused posteriorly with an anterior erosive defect within the vertebral bodies and the anterior fusion hardware at the C2-3 level no longer identified. The fiberoptic laryngoscopy demonstrated a 1 × 1 cm area over the importation of the hypopharynx, above the glotic area. The Gastrografin swallowing test ruled out any esophageal tear or fistula and confirmed the presence of a large ulcer on the posterior wall of the oropharynx. To the best of the authors' knowledge, this is the first ever reported case of a tear in the posterior pharyngeal wall along with extrusion of the entire cervical

  1. Effects of Melt Processing on Evolution of Structure in PEEK

    NASA Technical Reports Server (NTRS)

    Georgiev, Georgi; Dai, Patrick Shuanghua; Oyebode, Elizabeth; Cebe, Peggy; Capel, Malcolm

    1999-01-01

    We report on the effects of melt processing temperature on structure formation in Poly(ether-ether-ketone), PEEK. Real time Small Angle X-ray Scattering, SAXS, and thermal analysis are used to follow the melting behavior after various stages of processing. Assignment of peaks to structural entities within the material, the relative perfection of the crystals, and the possibility of their reorganization, are all influenced by the melt processing history. With the advent of high intensity synchrotron sources of X-radiation, polymer scientists gain a research tool which, when used along with thermal analysis, provides additional structural information about the crystals during growth and subsequent melting. PEEK is an engineering thermoplastic polymer with a very high glass transition temperature (145 C) and crystal melting point (337 C). PEEK has been the subject of recent studies by X-ray scattering in which melt and cold crystallization were followed in real-time. X-ray scattering and thermal studies have been used to address the formation of dual endothermic response which has been variously ascribed to lamellar insertion, dual crystal populations, or melting followed by re-crystallization. Another important issue is whether all of the amorphous phase is located in interlamellar regions, or alternatively whether some is located in "pockets" away from the crystalline lamellar stacks. The interpretation of scattering from lamellar stacks varies depending upon whether such amorphous pockets are formed. Some groups believe all of the amorphous phase is interlamellar. This leads to selection of a smaller thickness for the crystals. Other groups suggest that most amorphous phase is not interlamellar, and this leads to the suggestion that the crystal thickness is larger than the amorphous layer within the stacks. To investigate these ideas, we used SAXS and Differential Scanning Calorimetry to compare results of single and dual stage melt crystallization of PEEK using a

  2. Effects of Melt Processing on Evolution of Structure in PEEK

    NASA Technical Reports Server (NTRS)

    Georgiev, Georgi; Dai, Patrick Shuanghua; Oyebode, Elizabeth; Cebe, Peggy; Capel, Malcolm

    1999-01-01

    We report on the effects of melt processing temperature on structure formation in Poly(ether-ether-ketone), PEEK. Real time Small Angle X-ray Scattering, SAXS, and thermal analysis are used to follow the melting behavior after various stages of processing. Assignment of peaks to structural entities within the material, the relative perfection of the crystals, and the possibility of their reorganization, are all influenced by the melt processing history. With the advent of high intensity synchrotron sources of X-radiation, polymer scientists gain a research tool which, when used along with thermal analysis, provides additional structural information about the crystals during growth and subsequent melting. PEEK is an engineering thermoplastic polymer with a very high glass transition temperature (145 C) and crystal melting point (337 C). PEEK has been the subject of recent studies by X-ray scattering in which melt and cold crystallization were followed in real-time. X-ray scattering and thermal studies have been used to address the formation of dual endothermic response which has been variously ascribed to lamellar insertion, dual crystal populations, or melting followed by re-crystallization. Another important issue is whether all of the amorphous phase is located in interlamellar regions, or alternatively whether some is located in "pockets" away from the crystalline lamellar stacks. The interpretation of scattering from lamellar stacks varies depending upon whether such amorphous pockets are formed. Some groups believe all of the amorphous phase is interlamellar. This leads to selection of a smaller thickness for the crystals. Other groups suggest that most amorphous phase is not interlamellar, and this leads to the suggestion that the crystal thickness is larger than the amorphous layer within the stacks. To investigate these ideas, we used SAXS and Differential Scanning Calorimetry to compare results of single and dual stage melt crystallization of PEEK using a

  3. Effects of Melt Processing on Evolution of Structure in PEEK

    NASA Technical Reports Server (NTRS)

    Georgiev, Georgi; Dai, Patrick Shuanghua; Oyebode, Elizabeth; Cebe, Peggy; Capel, Malcolm

    1999-01-01

    We report on the effects of melt processing temperature on structure formation in Poly(ether-ether-ketone), PEEK. Real time Small Angle X-ray Scattering, SAXS, and thermal analysis are used to follow the melting behavior after various stages of processing. Assignment of peaks to structural entities within the material, the relative perfection of the crystals, and the possibility of their reorganization, are all influenced by the melt processing history. With the advent of high intensity synchrotron sources of X-radiation, polymer scientists gain a research tool which, when used along with thermal analysis, provides additional structural information about the crystals during growth and subsequent melting. PEEK is an engineering thermoplastic polymer with a very high glass transition temperature (145 C) and crystal melting point (337 C). PEEK has been the subject of recent studies by X-ray scattering in which melt and cold crystallization were followed in real-time. X-ray scattering and thermal studies have been used to address the formation of dual endothermic response which has been variously ascribed to lamellar insertion, dual crystal populations, or melting followed by re-crystallization. Another important issue is whether all of the amorphous phase is located in interlamellar regions, or alternatively whether some is located in "pockets" away from the crystalline lamellar stacks. The interpretation of scattering from lamellar stacks varies depending upon whether such amorphous pockets are formed. Some groups believe all of the amorphous phase is interlamellar. This leads to selection of a smaller thickness for the crystals. Other groups suggest that most amorphous phase is not interlamellar, and this leads to the suggestion that the crystal thickness is larger than the amorphous layer within the stacks. To investigate these ideas, we used SAXS and Differential Scanning Calorimetry to compare results of single and dual stage melt crystallization of PEEK using a

  4. Tribological assessment of a flexible carbon-fibre-reinforced poly(ether-ether-ketone) acetabular cup articulating against an alumina femoral head.

    PubMed

    Scholes, S C; Inman, I A; Unsworth, A; Jones, E

    2008-04-01

    New material combinations have been introduced as the bearing surfaces of hip prostheses in an attempt to prolong their life by overcoming the problems of failure due to wear-particle-induced osteolysis. This will hopefully reduce the need for revision surgery. The study detailed here used a hip simulator to assess the volumetric wear rates of large-diameter carbon-fibre-reinforced pitch-based poly(ether-ether-ketone) (CFR-PEEK) acetabular cups articulating against alumina femoral heads. The joints were tested for 25 x 10(6) cycles. Friction tests were also performed on these joints to determine the lubrication regime under which they operate. The average volumetric wear rate of the CFR-PEEK acetabular component of 54 mm diameter was 1.16 mm(3)/10(6) cycles, compared with 38.6 mm(3)/10(6) cycles for an ultra-high-molecular-weight polyethylene acetabular component of 28 mm diameter worn against a ceramic head. This extremely low wear rate was sustained over 25 x 10(6) cycles (the equivalent of up to approximately 25 years in vivo). The frictional studies showed that the joints worked under the mixed-boundary lubrication regime. The low wear produced by these joints showed that this novel joint couple offers low wear rates and therefore may be an alternative material choice for the reduction of osteolysis.

  5. Analysis of Carbon Fiber Reinforced PEEK Hinge Mechanism Articulation Components in a Rotating Hinge Knee Design: A Comparison of In Vitro and Retrieval Findings

    PubMed Central

    Giurea, Alexander; Pfaff, Andreas M.; Tozzi, Gianluca

    2016-01-01

    Carbon fiber reinforced poly-ether-ether-ketone (CFR-PEEK) represents a promising alternative material for bushings in total knee replacements, after early clinical failures of polyethylene in this application. The objective of the present study was to evaluate the damage modes and the extent of damage observed on CFR-PEEK hinge mechanism articulation components after in vivo service in a rotating hinge knee (RHK) system and to compare the results with corresponding components subjected to in vitro wear tests. Key question was if there were any similarities or differences between in vivo and in vitro damage characteristics. Twelve retrieved RHK systems after an average of 34.9 months in vivo underwent wear damage analysis with focus on the four integrated CFR-PEEK components and distinction between different damage modes and classification with a scoring system. The analysis included visual examination, scanning electron microscopy, and energy dispersive X-ray spectroscopy, as well as surface roughness and profile measurements. The main wear damage modes were comparable between retrieved and in vitro specimens (n = 3), whereby the size of affected area on the retrieved components showed a higher variation. Overall, the retrieved specimens seemed to be slightly heavier damaged which was probably attributable to the more complex loading and kinematic conditions in vivo. PMID:28101512

  6. Analysis of Carbon Fiber Reinforced PEEK Hinge Mechanism Articulation Components in a Rotating Hinge Knee Design: A Comparison of In Vitro and Retrieval Findings.

    PubMed

    Schierjott, Ronja A; Giurea, Alexander; Neuhaus, Hans-Joachim; Schwiesau, Jens; Pfaff, Andreas M; Utzschneider, Sandra; Tozzi, Gianluca; Grupp, Thomas M

    2016-01-01

    Carbon fiber reinforced poly-ether-ether-ketone (CFR-PEEK) represents a promising alternative material for bushings in total knee replacements, after early clinical failures of polyethylene in this application. The objective of the present study was to evaluate the damage modes and the extent of damage observed on CFR-PEEK hinge mechanism articulation components after in vivo service in a rotating hinge knee (RHK) system and to compare the results with corresponding components subjected to in vitro wear tests. Key question was if there were any similarities or differences between in vivo and in vitro damage characteristics. Twelve retrieved RHK systems after an average of 34.9 months in vivo underwent wear damage analysis with focus on the four integrated CFR-PEEK components and distinction between different damage modes and classification with a scoring system. The analysis included visual examination, scanning electron microscopy, and energy dispersive X-ray spectroscopy, as well as surface roughness and profile measurements. The main wear damage modes were comparable between retrieved and in vitro specimens (n = 3), whereby the size of affected area on the retrieved components showed a higher variation. Overall, the retrieved specimens seemed to be slightly heavier damaged which was probably attributable to the more complex loading and kinematic conditions in vivo.

  7. The influence of sterilization processes on the micromechanical properties of carbon fiber-reinforced PEEK composites for bone implant applications.

    PubMed

    Godara, A; Raabe, D; Green, S

    2007-03-01

    The effect of sterilization on the structural integrity of the thermoplastic matrix composite polyetheretherketone (PEEK) reinforced with carbon fibers (CF) is investigated by nanoindentation and nanoscratch tests. The use of the material as a medical implant grade requires a detailed understanding of the micromechanical properties which primarily define its in vivo behavior. Sterilization is a mandatory process for such materials used in medical applications like bone implants. The steam and gamma radiation sterilization processes employed in this study are at sufficient levels to affect the micromechanical properties of some polymer materials, particularly in the interphase region between the polymer matrix and the reinforcing fibers. Nanoindentation and nanoscratch tests are used in this work to reveal local gradients in the hardness and the elastic properties of the interphase regions. Both methods help to explore microscopic changes in the hardness, reduced stiffness and scratch resistance in the interphase region and in the bulk polymer matrix due to the different sterilization processes employed. The results reveal that neither steam nor gamma radiation sterilization entails significant changes of the reduced elastic modulus, hardness or coefficient of friction in the bulk polymer matrix. However, minor material changes of the PEEK matrix were observed in the interphase region. Of the two sterilization methods used, the steam treatment has a more significant influence on these small changes in this region and appears to increase slightly the thickness of the interphase zone.

  8. Safety of retained microcatheters: an evaluation of radiofrequency heating in endovascular microcatheters with nitinol, tungsten, and polyetheretherketone braiding at 1.5 T and 3 T

    PubMed Central

    Losey, Aaron D.; Lillaney, Prasheel; Martin, Alastair J.; Halbach, Van V.; Cooke, Daniel L.; Dowd, Christopher F.; Higashida, Randall T.; Saloner, David A.; Wilson, Mark W.; Saeed, Maythem; Hetts, Steven W.

    2013-01-01

    Background The use of ethylene-vinyl alcohol copolymer for liquid embolization of cranial vascular lesions has resulted in microcatheter fragments entrapped in patients following endovascular procedures. Undergoing subsequent diagnostic MRI examinations poses a safety concern due to the possibility of radiofrequency heating of the metallic braid incorporated into the microcatheter. Heating of nitinol, tungsten, and polyetheretherketone (PEEK) braided microcatheters was assessed and compared using a phantom model. Methods Microcatheters coupled with fluoroptic temperature probes were embedded in a polyacrylamide gel within a head and torso phantom. Experiments were performed at 1.5 T and 3 T, analyzing the effects of different catheter immersion lengths, specific absorption rate (SAR) levels, short clinical scans, long clinical scans, and microcatheter fragment lengths. Results The maximal increase in temperature for the nitinol braided microcatheter during a 15 min scan was 3.06°C using the T1 fast spin echo sequence at 1.5 T and 0.45°C using the balanced steady state free precession sequence at 3 T. The same scans for fragment lengths of 9, 18, 36, and 72 cm produced maximal temperature rises of 0.68, 0.80, 1.70, and 1.07°C at 1.5 T, respectively. The temperature changes at 3 T for these fragment lengths were 0.66, 0.83, 1.07, and 0.72°C, respectively. The tungsten and PEEK braided microcatheters did not demonstrate heating. Conclusions Substantial heating of nitinol braided microcatheters occurred and was a function of SAR level and geometric considerations. SAR and time limitations on MR scanning are proposed for patients with this microcatheter entrapped in their vasculature. In contrast, tungsten and PEEK braided microcatheters showed potential safe use in MRI. PMID:23685793

  9. Effect of surface roughness on osteogenesis in vitro and osseointegration in vivo of carbon fiber-reinforced polyetheretherketone-nanohydroxyapatite composite.

    PubMed

    Deng, Yi; Liu, Xiaochen; Xu, Anxiu; Wang, Lixin; Luo, Zuyuan; Zheng, Yunfei; Deng, Feng; Wei, Jie; Tang, Zhihui; Wei, Shicheng

    2015-01-01

    As United States Food and Drug Administration-approved implantable material, carbon fiber-reinforced polyetheretherketone (CFRPEEK) possesses an adjustable elastic modulus similar to cortical bone and is a prime candidate to replace surgical metallic implants. The bioinertness and inferior osteogenic properties of CFRPEEK, however, limit its clinical application as orthopedic/dental implants. In this study, CFRPEEK-nanohydroxyapatite ternary composites (PEEK/n-HA/CF) with variable surface roughness have been successfully fabricated. The effect of surface roughness on their in vitro cellular responses of osteoblast-like MG-63 cells (attachment, proliferation, apoptosis, and differentiation) and in vivo osseointegration is evaluated. The results show that the hydrophilicity and the amount of Ca ions on the surface are significantly improved as the surface roughness of composite increases. In cell culture tests, the results reveal that the cell proliferation rate and the extent of osteogenic differentiation of cells are a function of the size of surface roughness. The composite with moderate surface roughness significantly increases cell attachment/proliferation and promotes the production of alkaline phosphatase (ALP) activity and calcium nodule formation compared with the other groups. More importantly, the PEEK/n-HA/CF implant with appropriate surface roughness exhibits remarkably enhanced bioactivity and osseointegration in vivo in the animal experiment. These findings will provide critical guidance for the design of CFRPEEK-based implants with optimal roughness to regulate cellular behaviors, and to enhance biocompability and osseointegration. Meanwhile, the PEEK/n-HA/CF ternary composite with optimal surface roughness might hold great potential as bioactive biomaterial for bone grafting and tissue engineering applications.

  10. First Magnetic Resonance Imaging-Guided Aortic Stenting and Cava Filter Placement Using a Polyetheretherketone-Based Magnetic Resonance Imaging-Compatible Guidewire in Swine: Proof of Concept

    SciTech Connect

    Kos, Sebastian; Huegli, Rolf; Hofmann, Eugen; Quick, Harald H.; Kuehl, Hilmar; Aker, Stephanie; Kaiser, Gernot M.; Borm, Paul J. A.; Jacob, Augustinus L.; Bilecen, Deniz

    2009-05-15

    The purpose of this study was to demonstrate feasibility of percutaneous transluminal aortic stenting and cava filter placement under magnetic resonance imaging (MRI) guidance exclusively using a polyetheretherketone (PEEK)-based MRI-compatible guidewire. Percutaneous transluminal aortic stenting and cava filter placement were performed in 3 domestic swine. Procedures were performed under MRI-guidance in an open-bore 1.5-T scanner. The applied 0.035-inch guidewire has a PEEK core reinforced by fibres, floppy tip, hydrophilic coating, and paramagnetic markings for passive visualization. Through an 11F sheath, the guidewire was advanced into the abdominal (swine 1) or thoracic aorta (swine 2), and the stents were deployed. The guidewire was advanced into the inferior vena cava (swine 3), and the cava filter was deployed. Postmortem autopsy was performed. Procedural success, guidewire visibility, pushability, and stent support were qualitatively assessed by consensus. Procedure times were documented. Guidewire guidance into the abdominal and thoracic aortas and the inferior vena cava was successful. Stent deployments were successful in the abdominal (swine 1) and thoracic (swine 2) segments of the descending aorta. Cava filter positioning and deployment was successful. Autopsy documented good stent and filter positioning. Guidewire visibility through applied markers was rated acceptable for aortic stenting and good for venous filter placement. Steerability, pushability, and device support were good. The PEEK-based guidewire allows either percutaneous MRI-guided aortic stenting in the thoracic and abdominal segments of the descending aorta and filter placement in the inferior vena cava with acceptable to good device visibility and offers good steerability, pushability, and device support.

  11. First magnetic resonance imaging-guided aortic stenting and cava filter placement using a polyetheretherketone-based magnetic resonance imaging-compatible guidewire in swine: proof of concept.

    PubMed

    Kos, Sebastian; Huegli, Rolf; Hofmann, Eugen; Quick, Harald H; Kuehl, Hilmar; Aker, Stephanie; Kaiser, Gernot M; Borm, Paul J A; Jacob, Augustinus L; Bilecen, Deniz

    2009-05-01

    The purpose of this study was to demonstrate feasibility of percutaneous transluminal aortic stenting and cava filter placement under magnetic resonance imaging (MRI) guidance exclusively using a polyetheretherketone (PEEK)-based MRI-compatible guidewire. Percutaneous transluminal aortic stenting and cava filter placement were performed in 3 domestic swine. Procedures were performed under MRI-guidance in an open-bore 1.5-T scanner. The applied 0.035-inch guidewire has a PEEK core reinforced by fibres, floppy tip, hydrophilic coating, and paramagnetic markings for passive visualization. Through an 11F sheath, the guidewire was advanced into the abdominal (swine 1) or thoracic aorta (swine 2), and the stents were deployed. The guidewire was advanced into the inferior vena cava (swine 3), and the cava filter was deployed. Postmortem autopsy was performed. Procedural success, guidewire visibility, pushability, and stent support were qualitatively assessed by consensus. Procedure times were documented. Guidewire guidance into the abdominal and thoracic aortas and the inferior vena cava was successful. Stent deployments were successful in the abdominal (swine 1) and thoracic (swine 2) segments of the descending aorta. Cava filter positioning and deployment was successful. Autopsy documented good stent and filter positioning. Guidewire visibility through applied markers was rated acceptable for aortic stenting and good for venous filter placement. Steerability, pushability, and device support were good. The PEEK-based guidewire allows either percutaneous MRI-guided aortic stenting in the thoracic and abdominal segments of the descending aorta and filter placement in the inferior vena cava with acceptable to good device visibility and offers good steerability, pushability, and device support.

  12. Optimizing surface characteristics for cell adhesion and proliferation on titanium plasma spray coatings on polyetheretherketone.

    PubMed

    Yoon, Byung Jo Victor; Xavier, Fred; Walker, Brendon R; Grinberg, Samuel; Cammisa, Frank P; Abjornson, Celeste

    2016-10-01

    Titanium plasma spray coating on polyetheretherketone (PEEK) is a recent innovation to interbody spacer technology. The inherent hydrophobic properties of standard, uncoated PEEK implants can hamper cell attachment and bone healing during fusion. The addition of titanium coating not only offers initial stability due to increased surface roughness but also long-term stability due to bony ongrowth created from osteoconductive microenvironment on the device surface. The previously established hydrophilic and osteophilic properties of commercially pure titanium (CPTi) can potentially provide an ideal environment promoting cell attachment and bony ongrowth when applied at the end plate level of the fusion site. Because the surface material composition and topography is what seems to directly affect cell adhesion, it is important to determine the ideal titanium coating for the highest effectiveness. The purpose of the study is to determine whether there is an optimal surface roughness for the titanium coatings and whether different polishing methods have a greater effect than roughness or topography in mediating cell adhesion to the surface. The study was divided into two phases. In Phase 1, the effects of varying surface roughnesses on identical polishing method were compared. In Phase 2, the effect of varying polishing methods was compared on identical surface roughnesses. Coating thickness, porosity, and surface roughness were characterized using an optical microscope as per ASTM F 1854 standards. For both phases, PEEK coupons with plasma-sprayed CPTi were used, and human mesenchymal stem cells (hMSCs) at an initial density of 25,000 cells/cm(2) were seeded and cultured for 24 hours before fixation in 10% formalin. The cultured hMSCs were visualized by 4',6-diamidino-2-phenylindole (DAPI) staining, a fluorescent stain that binds to the DNA of living cells. Samples were imaged using an environmental scanning electron microscope (eSEM) (Carl Zeiss Microscopy

  13. Anterior cervical discectomy and fusion (ACDF) autograft versus graft substitutes: what do patients prefer?—A clinical study

    PubMed Central

    Maharaj, Monish M.; Phan, Kevin

    2016-01-01

    Background Patient dissatisfaction with donor site morbidity has led to the search for alternative grafting options and techniques. This report compares patient satisfaction rates between autograft and graft substitutes for anterior cervical discectomy and fusion (ACDF). Methods This study was performed with the approval of the local area health network ethics committee. Over a 9-year period, the author performed 574 ACDF procedures (697 levels). Of these, 22 patients had previous surgery with autograft, with a subsequent ACDF procedure performed using a graft substitute. Patients rated their satisfaction with pain, recovery, and preference of autograft versus a bone graft substitute. Graft substitutes used include: tricalcium phosphate/hydroxyapatite (TCP/HA) composite and iFactor placed within a polyetheretherketone (PEEK) cage. Results Results demonstrated that 21/22 patients achieved a solid fusion with the graft substitute. A total of 20/22 patients rated the autograft incision more painful than the anterior cervical incision, and 21/22 preferred the graft substitute. Three patients had adjacent segment disc replacement performed after autograft/ACDF. All patients reported preference for the total disc replacement (TDR) procedure in terms of recovery and postoperative pain. Conclusions Patient satisfaction with bone graft substitutes is very high compared with autograft with all but one (21/22) preferring the graft substitute option. The author questions the traditional recommendation that autograft is the “gold standard” for ACDF. In modern age of graft substitutes, autograft should not be considered the gold standard, but an index option between other options for comparison. PMID:27683706

  14. Influence of interphase layer on the overall elasto-plastic behaviors of HA/PEEK biocomposite.

    PubMed

    Fan, J P; Tsui, C P; Tang, C Y; Chow, C L

    2004-10-01

    A three-dimensional finite element unit cell model has been designed and constructed for studying mechanical properties of hydroxyapatite (HA) reinforced polyetheretherketone (PEEK) biocomposite. The model consists of an elastic-brittle HA spherical particle, an elasto-plastic matrix and an interphase layer between the particle and the matrix. The interphase layers with four different kinds of material behaviors have been taken into consideration to examine their effects on the overall properties of the composite. The damage evolution in the matrix and the interphase layer, and the interface failure, were also taken into account. Some other factors, such as mesh sensitivity, loading velocity and mass scale scheme, were also discussed in this investigation. A general-purpose finite element software package, ABAQUS, incorporated with a user-defined material subroutine, was used to perform the analysis. The predicted results were compared with the experimental data obtained from existing literatures. The results predicted by using the cell model with consideration of the matrix degradation and the effects of the damage and failure on the interphase layer are in good agreement with the experimental ones. Hence, the suitability of our proposed cell model incorporated with an appropriate type of the interphase layer for modeling the mechanical properties of the particulate biocomposite could be verified. Copyright 2004 Elsevier Ltd.

  15. PEEK Cages in Lumbar Fusion: Mid-term Clinical Outcome and Radiologic Fusion.

    PubMed

    Schimmel, Janneke J P; Poeschmann, Marcel S; Horsting, Philip P; Schönfeld, Dirk H W; van Limbeek, Jacques; Pavlov, Paul W

    2016-06-01

    Historical cohort analysis. Evaluation of mid-term clinical outcome and radiologic fusion in patients treated with a polyetheretherketone (PEEK) cage. Anterior lumbar interbody fusion can be a good alternative in chronic low back pain when conservative treatment fails. Although titanium alloy cages give good fusion rates, disadvantages are the subsidence of the cage in the adjacent vertebrae and problematic radiologic evaluation of fusion. PEEK cages such as the Synfix-LR cage (Synthes, Switzerland) should overcome this. From December 2004 until August 2007, 95 patients (21 double-level and 74 single-level) with degenerative disk disease from L3-S1 were operated by a single surgeon. The number of reoperations was counted. Radiologic fusion on computed tomography scan was scored with a new scoring system by an independent skeletal radiologist and orthopedic surgeon. Intraobserver agreement and specificity were assessed. Clinical improvement was measured by the Oswestry Disability Index score. The median duration of clinical follow-up was 47.7 months (range 29.9-61.6). In total, 26 patients were reoperated after a median period of 17.6 months (range 6.7-46.9) of the initial surgery. Of the 26 patients, 23 patients (18 single-level and 5 double-level) were reoperated for symptomatic pseudarthrosis. A moderate agreement (κ=0.36) and a specificity of 70% and 37% for the radiologist and orthopedic surgeon, respectively, were found for scoring bony bridging. The Oswestry Disability Index score improved after initial surgery; however, reoperated patients reported a significantly lower improvement. A high number of reoperations after an anterior lumbar interbody fusion procedure with the Synfix-LR cage were found, mainly because of symptomatic pseudarthrosis. The absence of posterior fixation in combination with lower stiffness and the hydrophobic characteristics of PEEK probably lead to insufficient initial stability, creating suboptimal conditions for bony bridging, and

  16. A Lower T1 Slope as a Predictor of Subsidence in Anterior Cervical Discectomy and Fusion with Stand-Alone Cages

    PubMed Central

    Lee, Su Hun; Lee, Jun Seok; Sung, Soon Ki; Son, Dong Wuk; Lee, Sang Weon; Song, Geun Sung

    2017-01-01

    Objective Preoperative parameters including the T1 slope (T1S) and C2–C7 sagittal vertical axis (SVA) have been recognized as predictors of kyphosis after laminoplasty, which is accompanied by posterior neck muscle damage. The importance of preoperative parameters has been under-estimated in anterior cervical discectomy and fusion (ACDF) because there is no posterior neck muscle damage. We aimed to determine whether postoperative subsidence and pseudarthrosis could be predicted according to specific parameters on preoperative plain radiographs. Methods We retrospectively analyzed 41 consecutive patients (male: female, 22: 19; mean age, 51.15±9.25 years) who underwent ACDF with a stand-alone polyether-ether-ketone (PEEK) cage (>1 year follow-up). Parameters including SVA, T1S, segmental angle and range of motion (ROM), C2–C7 cervical angle and ROM, and segmental inter-spinous distance were measured on preoperative plain radiographs. Risk factors of subsidence and pseudarthrosis were determined using multivariate logistic regression. Results Fifty-five segments (27 single-segment and 14 two-segment fusions) were included. The subsidence and pseudarthrosis rates based on the number of segments were 36.4% and 29.1%, respectively. Demographic data and fusion level were unrelated to subsidence. A greater T1S was associated with a lower risk of subsidence (p=0.017, odds ratio=0.206). A cutoff value of T1S<28° significantly predicted subsidence (sensitivity: 70%, specificity: 68.6%). There were no preoperative predictors of pseudarthrosis except old age. Conclusion A lower T1S (T1S<28°) could be a risk factor of subsidence following ACDF. Surgeons need to be aware of this risk factor and should consider various supportive procedures to reduce the subsidence rates for such cases. PMID:28881120

  17. A Lower T1 Slope as a Predictor of Subsidence in Anterior Cervical Discectomy and Fusion with Stand-Alone Cages.

    PubMed

    Lee, Su Hun; Lee, Jun Seok; Sung, Soon Ki; Son, Dong Wuk; Lee, Sang Weon; Song, Geun Sung

    2017-09-01

    Preoperative parameters including the T1 slope (T1S) and C2-C7 sagittal vertical axis (SVA) have been recognized as predictors of kyphosis after laminoplasty, which is accompanied by posterior neck muscle damage. The importance of preoperative parameters has been under-estimated in anterior cervical discectomy and fusion (ACDF) because there is no posterior neck muscle damage. We aimed to determine whether postoperative subsidence and pseudarthrosis could be predicted according to specific parameters on preoperative plain radiographs. We retrospectively analyzed 41 consecutive patients (male: female, 22: 19; mean age, 51.15±9.25 years) who underwent ACDF with a stand-alone polyether-ether-ketone (PEEK) cage (>1 year follow-up). Parameters including SVA, T1S, segmental angle and range of motion (ROM), C2-C7 cervical angle and ROM, and segmental inter-spinous distance were measured on preoperative plain radiographs. Risk factors of subsidence and pseudarthrosis were determined using multivariate logistic regression. Fifty-five segments (27 single-segment and 14 two-segment fusions) were included. The subsidence and pseudarthrosis rates based on the number of segments were 36.4% and 29.1%, respectively. Demographic data and fusion level were unrelated to subsidence. A greater T1S was associated with a lower risk of subsidence (p=0.017, odds ratio=0.206). A cutoff value of T1S<28° significantly predicted subsidence (sensitivity: 70%, specificity: 68.6%). There were no preoperative predictors of pseudarthrosis except old age. A lower T1S (T1S<28°) could be a risk factor of subsidence following ACDF. Surgeons need to be aware of this risk factor and should consider various supportive procedures to reduce the subsidence rates for such cases.

  18. A new alternative to expandable pedicle screws: Expandable poly-ether-ether-ketone shell.

    PubMed

    Demir, Teyfik

    2015-05-01

    Screw pullout is a very common problem in the fixation of sacrum with pedicle screws. The principal cause of this problem is that the cyclic micro motions in the fixation of sacrum are higher than the other regions of the vertebrae that limit the osteo-integration between bone and screw. In addition to that, the bone quality is very poor at sacrum region. This study investigated a possible solution to the pullout problem without the expandable screws' handicaps. Newly designed poly-ether-ether-ketone expandable shell and classical pedicle screws were biomechanically compared. Torsion test, pullout tests, fatigue tests, flexion/extension moment test, axial gripping capacity tests and torsional gripping capacity tests were conducted in accordance with ASTM F543, F1798 and F1717. Standard polyurethane foam and calf vertebrae were used as embedding medium for pullout tests. Classical pedicle screw pullout load on polyurethane foam was 564.8 N compared to the failure load for calf vertebrae's 1264 N. Under the same test conditions, expandable poly-ether-ether-ketone shell system's pullout loads from polyurethane foam and calf vertebrae were 1196.3 and 1890 N, respectively. The pullout values for expandable poly-ether-ether-ketone shell were 33% and 53% higher than classical pedicle screw on polyurethane foam and calf vertebrae, respectively. The expandable poly-ether-ether-ketone shell exhibited endurance on its 90% of yield load. Contrary to poly-ether-ether-ketone shell, classical pedicle screw exhibited endurance on 70% of its yield load. Expandable poly-ether-ether-ketone shell exhibited much higher pullout performance than classical pedicle screw. Fatigue performance of expandable poly-ether-ether-ketone shell is also higher than classical pedicle screw due to damping the micro motion capacity of the poly-ether-ether-ketone. Expandable poly-ether-ether-ketone shell is a safe alternative to all other expandable pedicle screw systems on mechanical perspective.

  19. UV curable lens production using molecular weight controlled PEEK based acrylic oligomer (Ac-PEEK).

    PubMed

    İnan, Tulay Y; Yıldız, Emel; Karaca, Birsen; Dogan, Hacer; Vatansever, Alican; Nalbant, Muhammed; Eken, Koray

    2014-08-01

    We produced UV curable lenses with properties blocking short wave UV light. In the UV-curable formulations, we used an oligomer (Ac-PEEK) with another urethan oligomer (Mw = 2000). Radically active, molecular weight controlled Ac-PEEK was obtained by reacting 2-hydroxyl ethyl methacrylate with molecular- weight- controlled and isocyanate terminated PEEK (Mn = 4500). We characterized all synthesized monomer, oligomer and optical materials with UV/Vis spectrophotometer with interferogram, elemental analyser, mass spectrophotometer, proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermal gravimetric analyzer, differential scanning calorimeter, scanning electron microscopy and gas chromatography. Results suggested that newly synthesized oligomer with the structure of PEEK absorbs short wave UV-light. Ageing tests [ISO 11979-5, Ophthalmic implants-intraocular lenses (IOL)-Part 5: Biocompatibility] performed on the IOL materials were successful. High contact angle of the obtained lenses suggests that all lenses were hydrophobic and SEM results revealed that lenses are morphologically homogeneous. Based on all positive properties just mentioned, we safely conclude that the lenses produced in this study are very promising for IOL production.

  20. Mechanical properties and in vivo study of modified-hydroxyapatite/polyetheretherketone biocomposites.

    PubMed

    Ma, Rui; Li, Qiankuan; Wang, Lin; Zhang, Xianghua; Fang, Lin; Luo, Zhongkuan; Xue, Bai; Ma, Lei

    2017-04-01

    Polyether ether ketone (PEEK) has received much attention for its excellent mechanical properties and biocompatibility. Here, the silane coupling agent KH560 [γ-(2,3-epoxypropoxy)propyltrimethoxysilane] is used for graft modification of bioactive HA (hydroxyapatite) particles and for preparing HA/PEEK composites via a hot-press molding method. The prepared HA/PEEK composites were tested for their mechanical properties with SEM (scanning electron microscopy), infrared spectroscopy, and thermo-analysis. The results show that silane coupling KH-560 modifies HA successfully and that the tensile strengths of HA/PEEK and m-HA/PEEK composites indicate an increasing and then a decreasing tendency with increasing HA contents. The non-modified HA/PEEK composites display the same trend as the modified specimens with lower tensile strength and consist of sharp points. When the HA content is 5wt.%, the tensile strength of m-HA/PEEK composite reaches its maximum, which is 23% higher than that of pure PEEK specimens. The in vivo experiments of m-HA/PEEK used a biomechanical push-out test, SEM, optical microscopy, and an Image-Pro Express C image analysis system. The growth of the bone tissues around the m-HA/PEEK composites with an HA content of 5wt.% is better than that of specimens with different HA contents. This finding shows the nano-scale effect of the bioactive filler HA in PEEK substrates, which obviously contributes to the growth of the surrounding bone issues in vivo. This study could provide theoretical support for the further promotion and application of high-performance engineering plastics such as PEEK in biomedical fields. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. The Biotribology of PEEK-on-HXLPE Bearings Is Comparable to Traditional Bearings on a Multidirectional Pin-on-disk Tester.

    PubMed

    Baykal, Doruk; Siskey, Ryan S; Underwood, Richard J; Briscoe, Adam; Kurtz, Steven M

    2016-11-01

    All-polymer bearings involving polyetheretherketone (PEEK) have been proposed for orthopaedic applications because they may reduce stress shielding, reduce weight of the implants, reduce wear and risk of osteolysis, and prevent release of metal ions by replacing the metal articulating components. Little is known about the biotribology of all-polymer PEEK bearings, including the effects of cross-shear, which are relevant for implant longevity, especially in the hip, and increased temperature that may affect lubricant proteins and, hence, lubrication in the joint. Using pin-on-disk in vitro testing, we asked: (1) Can all-polymer bearing couples involving PEEK have a comparable or lower wear rate than highly crosslinked UHMWPE (HXLPE) on CoCr bearing couples? (2) Is the wear rate of PEEK bearing couples affected by the amount of cross-shear? (3) Is there a difference in wear mechanism and surface morphology for all-polymer bearing surfaces compared with UHMWPE (HXLPE) on CoCr? We simultaneously tested a total of 100 pin-on-disk couples (n = 10 per bearing couple) consisting of three traditional metal-on-UHMWPE and seven polymer-on-polymer bearings for 2 million cycles under physiologically relevant conditions and in accordance with ASTM F732. Using analysis of variance, we analyzed the effect of bearing surface topography and cross-shear on wear rate. The changes in surface topography were evaluated using optical microscopy. Sample size was sufficient to provide 80% power to detect a difference of 1.4 mm(3)/MC in average wear rates of bearing couples. The combined wear rates of all-polymer bearing couples were not different than traditional bearing couples. With the numbers available, the PEEK and HXLPE bearing couple had a mean wear rate (WR: mean ± SD) of 0.9 ± 1.1 mm(3)/MC (95% confidence interval [CI], 0.2-1.5 mm(3)/MC), which was not different than the wear rate of the CoCr and HXLPE bearing couple (1.6 ± 2.0 mm(3)/MC; 95% CI, 0.4-2.8 mm(3)/MC; mean difference

  2. Retention Load of Telescopic Crowns with Different Taper Angles between Cobalt-Chromium and Polyetheretherketone Made with Three Different Manufacturing Processes Examined by Pull-Off Test.

    PubMed

    Wagner, Christina; Stock, Veronika; Merk, Susanne; Schmidlin, Patrick R; Roos, Malgorzata; Eichberger, Marlis; Stawarczyk, Bogna

    2016-04-01

    To investigate the retention loads of differently fabricated secondary telescopic polyetheretherketone (PEEK) crowns on cobalt-chromium primary crowns with different tapers. Cobalt-chromium primary crowns with 0°, 1°, and 2° tapers were constructed, milled, and sintered. Corresponding secondary crowns were fabricated by milling, pressing from pellets, and pressing from granules. For these nine test groups, the pull-off tests of each crown combination were performed 20 times, and the retention loads were measured (Zwick 1445, 50 mm/min). Data were analyzed using linear regression, covariance analysis, mixed models, Kruskal-Wallis, and Mann-Whitney U-test, together with the Benferroni-Holm correction. The mixed models covariance analysis reinforced stable retention load values (p = 0.162) for each single test sequence. There was no interaction between the groups and the separation cycles (p = 0.179). Milled secondary crowns with 0° showed the lowest mean retention load values compared to all tested groups (p = 0.003) followed by those pressed form pellets with 1°. Regarding the different tapers, no effect of manufacturing method on the results was observed within 1° and 2° groups (p = 0.540; p = 0.052); however, among the 0° groups, the milled ones showed significantly the lowest retention load values (p = 0.002). Among the manufacturing methods, both pressed groups showed no impact of taper on the retention load values (p > 0.324 and p > 0.123, respectively), whereas among the milled secondary crowns, the 0° taper showed significantly lower retention load values than the 1° and 2° taper (p < 0.002). Based on these results, telescopic crowns made of PEEK seem to show stable retention load values for each test sequence; however, data with thermo-mechanical aging are still required. In addition, further developments in CAD/CAM manufacturing of PEEK materials for telescopic crowns are warranted, especially for 0°. © 2016 by the American College of

  3. The SNAP trial: a double blind multi-center randomized controlled trial of a silicon nitride versus a PEEK cage in transforaminal lumbar interbody fusion in patients with symptomatic degenerative lumbar disc disorders: study protocol

    PubMed Central

    2014-01-01

    Background Polyetheretherketone (PEEK) cages have been widely used in the treatment of lumbar degenerative disc disorders, and show good clinical results. Still, complications such as subsidence and migration of the cage are frequently seen. A lack of osteointegration and fibrous tissues surrounding PEEK cages are held responsible. Ceramic implants made of silicon nitride show better biocompatible and osteoconductive qualities, and therefore are expected to lower complication rates and allow for better fusion. Purpose of this study is to show that fusion with the silicon nitride cage produces non-inferior results in outcome of the Roland Morris Disability Questionnaire at all follow-up time points as compared to the same procedure with PEEK cages. Methods/Design This study is designed as a double blind multi-center randomized controlled trial with repeated measures analysis. 100 patients (18–75 years) presenting with symptomatic lumbar degenerative disorders unresponsive to at least 6 months of conservative treatment are included. Patients will be randomly assigned to a PEEK cage or a silicon nitride cage, and will undergo a transforaminal lumbar interbody fusion with pedicle screw fixation. Primary outcome measure is the functional improvement measured by the Roland Morris Disability Questionnaire. Secondary outcome parameters are the VAS leg, VAS back, SF-36, Likert scale, neurological outcome and radiographic assessment of fusion. After 1 year the fusion rate will be measured by radiograms and CT. Follow-up will be continued for 2 years. Patients and clinical observers who will perform the follow-up visits will be blinded for type of cage used during follow-up. Analyses of radiograms and CT will be performed independently by two experienced radiologists. Discussion In this study a PEEK cage will be compared with a silicon nitride cage in the treatment of symptomatic degenerative lumbar disc disorders. To our knowledge, this is the first randomized controlled

  4. PEEK Biomaterials in Trauma, Orthopedic, and Spinal Implants

    PubMed Central

    Kurtz, S. M.; Devine, J. N.

    2007-01-01

    Since the 1980s, polyaryletherketones (PAEKs) have been increasingly employed as biomaterials for trauma, orthopedic, and spinal implants. We have synthesized the extensive polymer science literature as it relates to structure, mechanical properties, and chemical resistance of PAEK biomaterials. With this foundation, one can more readily appreciate why this family of polymers will be inherently strong, inert, and biocompatible. Due to its relative inertness, PEEK biomaterials are an attractive platform upon which to develop novel bioactive materials, and some steps have already been taken in that direction, with the blending of HA and TCP into sintered PEEK. However, to date, blended HA-PEEK composites have involved a trade-off in mechanical properties in exchange for their increased bioactivity. PEEK has had the greatest clinical impact in the field of spine implant design, and PEEK is now broadly accepted as a radiolucent alternative to metallic biomaterials in the spine community. For mature fields, such as total joint replacements and fracture fixation implants, radiolucency is an attractive but not necessarily critical material feature. PMID:17686513

  5. Retrieval analysis of PEEK rods for posterior fusion and motion preservation.

    PubMed

    Kurtz, Steven M; Lanman, Todd H; Higgs, Genymphas; Macdonald, Daniel W; Berven, Sigurd H; Isaza, Jorge E; Phillips, Eual; Steinbeck, Marla J

    2013-12-01

    The purpose of this study was to analyze explanted PEEK rod spinal systems in the context of their clinical indications. We evaluated damage to the implant and histological changes in explanted periprosthetic tissues. 12 patients implanted with 23 PEEK rods were revised between 2008 and 2012. PEEK rods were of the same design (CD Horizon Legacy, Medtronic, Memphis TN, USA). Retrieved components were assessed for surface damage mechanisms, including plastic deformation, scratching, burnishing, and fracture. Patient history and indications for PEEK rod implantation were obtained from analysis of the medical records. 11/12 PEEK rod systems were employed for fusion at one level, and motion preservation at the adjacent level. Surgical complications in the PEEK cohort included a small dural tear in one case that was immediately repaired. There were no cases of PEEK rod fracture or pedicle screw fracture. Retrieved PEEK rods exhibited scratching, as well as impressions from the set screws and pedicle screw saddles. PEEK debris was observed in two patient tissues, which were located adjacent to PEEK rods with evidence of scratching and burnishing. This study documents the surface changes and tissue reactions for retrieved PEEK rod stabilization systems. Permanent indentations by the set screws and pedicle screws were the most prevalent observations on the surface of explanted PEEK rods.

  6. Crystalline ha coating on peek via chemical deposition

    NASA Astrophysics Data System (ADS)

    Almasi, D.; Izman, S.; Assadian, M.; Ghanbari, M.; Abdul Kadir, M. R.

    2014-09-01

    Polyether ether ketone (PEEK) has a similar elastic modulus to bone and can be a suitable alternative to metallic implants. However, PEEK is bioinert and does not integrate well with the surrounding tissues. The current commercial method for solving this problem is by coating PEEK substrates with calcium phosphates via plasma spraying. However, this method produces a low bonding strength between the substrate and the coating layer, as well as non-uniform density of the coating. In this study, chemical deposition was used to deposit HA crystalline particles on PEEK substrate without any subsequent crystallisation process therefore producing crystalline treated layer. EDX results confirmed the deposition of HA, and the XRD results confirmed that the treated layer was crystalline HA. FT-IR analysis confirmed the chemical bonding between HA and the substrate. Surface roughness increased from 24.27 nm to 34.08 nm for 3 min immersion time. The water contact angle showed an increase in wettability of the treated sample from 71.6 to 36.4 degrees, which in turn increased its bioactivity. The proposed method is a suitable alternative to other conventional methods as high temperature was not involved in the process which could damage the surface of the substrate.

  7. Viscoelastic properties of 3-D braided PEEK/graphite composites

    SciTech Connect

    Hu, Jian-Ni.

    1992-01-01

    In this study, 3-D braided PEEK/AS4 graphite composites were performed and processed to investigate the viscoelastic behavior of this new system. These manufactured composites were characterized to determine their fiber volume fractions and matrix crystallinity indices using matrix digestion and wide angle x-ray diffraction. After physical characterization, the mechanical response of these composites were evaluated at various temperatures. Experimental results from tensile measurements were compared to an established fabric geometry model (FGM). This model predicts tensile modules based upon fiber and matrix properties, fiber volume fraction, and braiding angle. Model predictions and experimental results are given here, and are in good agreement with each other. In order to study the time-dependent mechanical properties of these 3-D braided composites, their stress relaxation, creep and dynamic mechanical properties were evaluated. These results were then compared to a new composite model. This model combined a Quasi/linear Viscoelastic Model (QVM) for the viscoelastic behavior of PEEK with the FGM approach to predict the viscoelastic behavior of 3-D PEEK composites. The experimental stress relaxation and creep results are in good agreement with the QVM-FGM analysis. Thus, the QVM-FGM approach was used to accurately correlate these viscoelastic properties of 3-D braided PEEK/graphite composites. Through wider use and testing, this QVM/FGM approach may be used to increase our understanding and perhaps facilitate the design of composite structures.

  8. Peek-a-What? Infants' Response to the Still-Face Task after Normal and Interrupted Peek-a-Boo

    ERIC Educational Resources Information Center

    Bigelow, Ann E.; Best, Caitlin

    2013-01-01

    Infants' sensitivity to the vitality or tension envelope within dyadic social exchanges was investigated by examining their responses following normal and interrupted games of peek-a-boo embedded in a Still-Face Task. Infants 5-6 months old engaged in two modified Still-Face Tasks with their mothers. In one task, the initial interaction ended with…

  9. New Cervical Laminoplasty Polyethererketone Cage - Two Case Reports -

    PubMed Central

    Lee, Jae-Joon; Kim, Jong-Seon; Seo, Hyoung-Yeon

    2007-01-01

    Cervical laminoplasty is a widely used technique to enlarge the spinal canal for spinal cord decompression. The two common methods are an open door laminoplasty and a midline splitting laminoplasty. Several devices and materials have been used as a spacer for maintaining or stabilizing the lamina in the open or split position, however, some are difficult to implant. Moreover, they are not designed to restore the natural dynamics of the cervical spine, and can cause discomfort to the patient. There is a need to develop a device and material that will be effective in maintaining and stabilizing the position of the lamina after laminoplasty, being able to be implanted easily and safely to restore the natural dynamics of the cervical spine, as well as getting the bony union to the host bone. We report two cervical laminoplasty patients who were treated using a new laminoplasty polyetheretherketone cage. PMID:20411154

  10. New cervical laminoplasty polyethererketone cage - two case reports -.

    PubMed

    Chung, Jae-Yoon; Lee, Jae-Joon; Kim, Jong-Seon; Seo, Hyoung-Yeon

    2007-06-01

    Cervical laminoplasty is a widely used technique to enlarge the spinal canal for spinal cord decompression. The two common methods are an open door laminoplasty and a midline splitting laminoplasty. Several devices and materials have been used as a spacer for maintaining or stabilizing the lamina in the open or split position, however, some are difficult to implant. Moreover, they are not designed to restore the natural dynamics of the cervical spine, and can cause discomfort to the patient. There is a need to develop a device and material that will be effective in maintaining and stabilizing the position of the lamina after laminoplasty, being able to be implanted easily and safely to restore the natural dynamics of the cervical spine, as well as getting the bony union to the host bone. We report two cervical laminoplasty patients who were treated using a new laminoplasty polyetheretherketone cage.

  11. An Investigation of Graphite Peek Composite under Compression with a Centrally Located Circular Discontinuity

    DTIC Science & Technology

    1993-03-01

    body of research conducted on Gr/PEEK exists and includes the investigation of Gr/PEEK under both tension and compression with a centrally located cutout...Some of this research has discussed a need to include the nonlinear stress-strain behavior of the materials in the evaluation of the composite. This... research will investigate the nonlinear properties of Gr/PEEK using the nonlinear finite element program, PLNRS, and validate the results both with a

  12. Rolling contact fatigue testing of peek based composites

    NASA Astrophysics Data System (ADS)

    Avanzini, A.; Donzella, G.; Gallina, D.; Pandini, S.; Petrogalli, C.

    2010-06-01

    Rolling contact fatigue phenomenon was investigated on unfilled PEEK and on three different PEEK composites: 10% carbon micro-fiber, graphite and PTFE filled matrix, 30% carbon micro-fiber filled matrix, 30% glass micro-fiber filled matrix. For this aim, roller-shaped specimens were machined from extruded bars of these materials and subjected to rolling contact tests at different contact pressure levels by means of a four roller machine. Contact pressure-life diagrams and wear rates were so obtained and compared, highlighting a relationship with monotonic and hardness materials properties. Microscopic observations of contact surfaces and transversal section of the specimens also allowed observing the damage mechanisms occurred in the materials tested and the effects of the filler. In particular way, deep radial cracks appeared on unfilled PEEK, while spalling and delamination phenomena where found on composites. Diffuse microcracks were found at the filler-matrix interface of the composites specimens, confirming that the fatigue life of these materials is essentially determined by the crack propagation phase, also under rolling contact loading.

  13. PEEK and CFR-PEEK as alternative bearing materials to UHMWPE in a fixed bearing total knee replacement: An experimental wear study.

    PubMed

    Brockett, Claire L; Carbone, Silvia; Fisher, John; Jennings, Louise M

    2017-03-15

    New bearing materials for total joint replacement have been explored as the need to improve longevity and enhance performance is driven by the changing demands of the patient demographic. Carbon-reinforced PEEK has demonstrated good wear characteristics in experimental wear simulation in both simple geometry pin-on-plate studies and in total hip joint replacement. Carbon reinforced PEEK CFR-PEEK has the potential to reduce tibial insert thickness and preserve bone in the knee. This study investigated the wear performance of PEEK and CFR-PEEK in a low conformity total knee replacement configuration. Custom-made flat inserts were tested against cobalt-chromium femoral bearings in a knee wear simulation for a period of three million cycles. Wear was assessed gravimetrically at intervals throughout the study. The wear rates of both PEEK and CFR-PEEK were very high and almost two orders of magnitude higher than the wear rate of UHMWPE under comparable conditions. Evidence of mechanical failure of the materials, including surface cracking and delamination was observed in both materials. This study highlights that these materials may not be suitable alternatives for UHMWPE in low-conformity designs.

  14. Effect of sulfuric acid etching of polyetheretherketone on the shear bond strength to resin cements.

    PubMed

    Sproesser, Oliver; Schmidlin, Patrick R; Uhrenbacher, Julia; Roos, Malgorzata; Gernet, Wolfgang; Stawarczyk, Bogna

    2014-10-01

    To examine the influence of etching duration on the bond strength of PEEK substrate in combination with different resin composite cements. In total, 448 PEEK specimens were fabricated, etched with sulfuric acid for 5, 15, 30, 60, 90, 120, and 300 s and then luted with two conventional resin cements (RelyX ARC and Variolink II) and one self-adhesive resin cement (Clearfil SA Cement) (n = 18/subgroup). Non-etched specimens served as the control group. Specimens were stored in distilled water for 28 days at 37°C and shear bond strengths were measured. Data were analyzed nonparametrically using Kruskal-Wallis-H (p < 0.05). Non-etched PEEK demonstrated no bond strength to resin composite cements. The optimal etching duration varied with the type of resin composite: 60 s for RelyX ARC (15.3 ± 7.2 MPa), 90 s for Variolink II (15.2 ± 7.2 MPa), and 120 s for Clearfil SA Cement (6.4 ± 5.9 MPa). Regardless of etching duration, however, the self-etching resin composite cement showed significantly lower shear bond strength values when compared to groups luted with the conventional resin composites. Although sulfuric acid seems to be suitable and effective for PEEK surface pre-treatment, further investigations are required to examine the effect of other adhesive systems and cements.

  15. Histopathological Analysis of PEEK Wear Particle Effects on the Synovial Tissue of Patients

    PubMed Central

    Jansson, V.; Giurea, A.

    2016-01-01

    Introduction. Increasing interest developed in the use of carbon-fiber-reinforced-poly-ether-ether-ketones (CFR-PEEK) as an alternative bearing material in knee arthroplasty. The effects of CFR-PEEK wear in in vitro and animal studies are controversially discussed, as there are no data available concerning human tissue. The aim of this study was to analyze human tissue containing CFR-PEEK as well as UHMWPE wear debris. The authors hypothesized no difference between the used biomaterials. Methods and Materials. In 10 patients during knee revision surgery of a rotating-hinge-knee-implant-design, synovial tissue samples were achieved (tibial inserts: UHMWPE; bushings and flanges: CFR-PEEK). One additional patient received revision surgery without any PEEK components as a control. The tissue was paraffin-embedded, sliced into 2 μm thick sections, and stained with hematoxylin and eosin in a standard process. A modified panoptical staining was also done. Results. A “wear-type” reaction was seen in the testing and the control group. In all samples, the UHMWPE particles were scattered in the tissue or incorporated in giant cells. CFR-PEEK particles were seen as conglomerates and only could be found next to vessels. CFR-PEEK particles showed no giant-cell reactions. In conclusion, the hypothesis has to be rejected. UHMWPE and PEEK showed a different scatter-behavior in human synovial tissue. PMID:27766256

  16. Preparation Methods for Improving PEEK's Bioactivity for Orthopedic and Dental Application: A Review

    PubMed Central

    Almasi, Davood; Iqbal, Nida; Sadeghi, Maliheh; Sudin, Izman; Abdul Kadir, Mohammed Rafiq; Kamarul, Tunku

    2016-01-01

    There is an increased interest in the use of polyether ether ketone (PEEK) for orthopedic and dental implant applications due to its elastic modulus close to that of bone, biocompatibility, and its radiolucent properties. However, PEEK is still categorized as bioinert due to its low integration with surrounding tissues. Many studies have reported on methods to increase the bioactivity of PEEK, but there is still one-preparation method for preparing bioactive PEEK implant where the produced implant with desirable mechanical and bioactivity properties is required. The aim of this review is to present the progress of the preparation methods for improvement of the bioactivity of PEEK and to discuss the strengths and weaknesses of the existing methods. PMID:27127513

  17. Bioactive composites consisting of PEEK and calcium silicate powders.

    PubMed

    Kim, Ill Yong; Sugino, Atsushi; Kikuta, Koichi; Ohtsuki, Chikara; Cho, Sung Baek

    2009-08-01

    Bioactive bone-repairing materials with mechanical properties analogous to those of natural bone can be obtained through the combination of bioactive ceramic fillers with organic polymers. Previously, we developed novel bioactive microspheres in a binary CaO-SiO2 system produced through a sol-gel process as filler for the fabrication of composites. In this study, we fabricate bioactive composites in which polyetheretherketone is reinforced with 0-50 vol% 30CaO x 70SiO2 (CS) microspheres. The prepared composites reinforced with CS particles form hydroxyapatite on their surfaces in simulated body fluid. The induction periods of hydroxyapatite formation on the composites decrease with increasing amount of CS particles. The mechanical properties of the composites are evaluated by three-point bending test. The composites reinforced with 20 vol% CS particles show 123.5 MPa and 6.43 GPa in bending strength and Young's modulus, respectively.

  18. Stand-alone anchored cage versus cage with plating for single-level anterior cervical discectomy and fusion: a prospective, randomized, controlled study with a 2-year follow-up.

    PubMed

    Nemoto, Osamu; Kitada, Akira; Naitou, Satoko; Tachibana, Atsuko; Ito, Yuya; Fujikawa, Akira

    2015-07-01

    To avoid complications associated with plating in anterior cervical discectomy and fusion (ACDF), stand-alone anchored PEEK cage was developed and favourable outcomes with a low rate of dysphasia have been described. The objective of this study was to compare the clinical and radiological outcomes of ACDF using a standalone anchored PEEK cage (PREVAIL; Medtronic Sofamor Danek, Memphis, TN) with those of a PEEK cage with plating in a prospective randomized manner. Fifty patients with single-level cervical radiculopathy were randomly assigned to a PREVAIL or a PEEK cage with plating. Following 3, 6, 12, and 24 months, clinical and radiological outcomes were assessed. The mean surgical time for the patients with a PREVAIL was significantly shorter than that for those with a PEEK cage with plating. The clinical outcomes evaluated by visual analogue scale for pain and the Odom's criteria were comparable between both the groups. Both the groups demonstrated the high fusion rate (92% in PREVAIL; 96% in PEEK cage with plating). The subsidence rate and the improvement of cervical alignment were comparable between both the groups. The incidence of adjacent-level ossification was significantly lower for patients with a PREVAIL than that for those with a PEEK cage with plating. The rate of dysphasia graded by the method of Bazaz and measurement of prevertebral soft tissue swelling indicated no significant differences between both the groups. Our prospective randomized study confirmed that stand-alone anchored PEEK cage is a valid alternative to plating in ACDF with a low rate of adjacent-level ossification. However, the potential to reduce the incidence of dysphasia was not confirmed.

  19. Study on the Wettability and Tribological Behavior of Different Polymers as Bearing Materials for Cervical Prosthesis

    NASA Astrophysics Data System (ADS)

    Wang, Song; Song, Jian; Liao, Zhenhua; Liu, Yuhong; Zhang, Caixia; Liu, Weiqiang

    2015-06-01

    Tribological behaviors of four polymers (conventional and cross-linked UHMWPE, conventional and glass fiber-reinforced PEEK) articulated with Ti6Al4V ball were studied under both dry sliding and 25% bovine serum lubrication. The hardness, static contact angle, surface damage topography, and wear parameter of wear scar were tested. Both cross-linked process of UHMWPE and glass fiber-reinforced treatment of PEEK improved wettability while they did not increase hardness. PEEK revealed higher surface hardness and better wettability than UHMWPE. The dominant wear mechanisms for UHMWPE were plastic deformation and fatigue wear while the failure mechanisms were severe adhesive and abrasive wear for PEEK. Cross-linked process of UHMWPE could form multi-molecular arrangement and reduce stratification, also decreasing friction coefficient and wear rate in both dry sliding and lubrication conditions. However, glass fiber-reinforced treatment of PEEK only decreased its friction coefficient and wear rate in dry condition, which was closely related to the function and wear mechanism of glass fiber. Cross-linked UHMWPE revealed the lowest friction coefficient and wear rate under lubrication condition, which was attributed to the cross-linked treatment and the formation of both protein adsorption film and lubrication film. Hence, cross-linked UHMWPE may be an alternative polymer for use as artificial cervical disc bearing material when it articulated with Ti6Al4V.

  20. Debris of carbon-fibers originated from a CFRP (pEEK) wrist-plate triggered a destruent synovitis in human.

    PubMed

    Merolli, Antonio; Rocchi, Lorenzo; De Spirito, Marco; Federico, Francesco; Morini, Alessandro; Mingarelli, Luigi; Fanfani, Francesco

    2016-03-01

    Application of carbon-fiber-reinforced-polymer (CFRP) artifacts in humans has been promoted in Orthopedic and Trauma Surgery. Literature documents the biocompatibility of materials used, namely carbon fibers (CF) and poly-ether thermoplastics, like poly-ether-ether-ketone (PEEK). A properly designed and accurately implanted composite artifact should not expose its fibers during or after surgery: however this may happen. A white Caucasian woman came to our attention 11 months after surgery for a wrist fracture. She had a severe impairment, being unable to flex the thumb; index finger and distal phalanx of third finger. We retrieved a correctly positioned plate and documented an aggressive erosive flexor tendons synovitis with eroded stumps of flexor tendons. The plate and soft tissues were analyzed by Visible Light and Scanning Electron Microscopy. Histopathology showed granulomatous fibrogenic process with CF engulfed inside multinucleated giant cells. Fibers were unmasked and disrupted inside the holes where screws were tightened and corrugation of the polymer coating led to further unmasking. The mechanism of foreign-body reaction to CF has not been studied in depth yet, particularly at the ultrastructural level and in Humans. This case documents a damage occurred in a clinical application and which was theoretically possible. Our opinion is that a proper way to promote the use of CRFP in the Clinic in the short term is to direct Research towards finding a better way to prevent CF debris to be exposed and released. In the longer term, the biological response to CF deserves a deeper understanding.

  1. Cervical Spondylosis

    MedlinePlus

    ... al. Cervical spondylotic myelopathy. In: Textbook of the Cervical Spine. Philadelphia, Pa.: Saunders Elsevier; 2015. https://www.clinicalkey. ... Evaluation of the patient with neck pain and cervical spine disorders. http://www.uptodate.com/home. Accessed March ...

  2. Cervical disk arthroplasty versus ACDF for preoperative reducible kyphosis.

    PubMed

    Chen, Yu; Wang, Xinwei; Lu, Xuhua; Yang, Haisong; Chen, Deyu

    2013-07-01

    Cervical total disk arthroplasty has proven to be an effective and safe alternative for anterior cervical diskectomy and fusion (ACDF) for the treatment of cervical disk degenerative disease. However, whether and when cervical disk arthroplasty is indicated for preoperative cervical spine kyphosis is unclear. In the authors' clinical experiences, preoperative kyphosis can generally be divided into reducible and irreducible forms according to the results of dynamic flexion-extension lateral radiographs. Reducible kyphosis is mostly related to local disk prolapse, clinical symptoms, and musculature weakness, but irreducible kyphosis is always associated with significant cervical degeneration or congenital bone malformation. In this study, 32 patients with preoperative reducible kyphosis were randomized in a 1:1 ratio to either single-level total cervical arthroplasty with the Discover cervical disk prosthesis (DePuy Spine, Raynham, Massachusetts) (arthroplasty group) or single-level ACDF with a polyetheretherketone cage and plate (ACDF group). No significant differences existed in clinical and radiological results at 2-year follow-up between the arthroplasty and ACDF groups. The global and functional spinal unit angles of the arthroplasty group were significantly lower than those of the ACDF group 6 months postoperatively, which was consistent with the result of the comparison in Neck Disability Index score. However, the sagittal alignment of the overall cervical spine and the treated segment and the Neck Disability Index score significantly improved after 6 months in the arthroplasty group but not in the ACDF group. Therefore, preoperative reducible kyphosis is not a contraindication for cervical total disk arthroplasty. However, neck strength-building exercises should be emphasized for the postoperative rehabilitation after cervical total disk arthroplasty.

  3. Comparison of energy absorption of carbon/epoxy and carbon/PEEK composite tubes

    NASA Astrophysics Data System (ADS)

    Hamada, H.; Coppola, J. C.; Hull, D.; Maekawa, Z.; Sato, H.

    1992-07-01

    Axial compressive tests have been carried out on carbon fiber/epoxy and carbon fiber/PEEK tubes made from unidirectional prepreg materials. Three fiber architectures were investigated: unidirectional fibers parallel (0 deg) to the axis of the tube, +/- 30 deg, and +/- 45 deg. One set of tubes was machined with a 45-deg chamfer at one end in an attempt to trigger progressive crushing, and the other set had square ends to determine the compressive strength of the material. Stable progressive crushing occurred in +/- 45 deg carbon fiber/epoxy tubes and 0-deg carbon fiber/PEEK tubes where the crush stress was significantly lower than the compressive fracture strength. The 0-deg carbon fiber/PEEK tubes had a specific energy absorption of 180 kJ/kg, which is the highest value recorded for any material. This high value is interpreted in terms of the high interlaminar toughness of PEEK-matrix composites.

  4. New method in experimental damage study of AS4/PEEK composite laminates

    NASA Astrophysics Data System (ADS)

    Wang, Shibin; Tong, Jingwei; Yue, C.; Li, Linan; Shen, Min

    2002-06-01

    AS4/PEEK [0/+/- 45/90]7s composite laminates were subjected to a bending moment. We have obtained the displacement fields by moire interferometry with the aid of Long Distance Microscope. Based on wavelet analysis, the digital moire images were processed and analyzed. The special algorithms of unconstrained nonlinear minimization and the scale parameter were used to eliminate the influence of the noise in the digital image processing. Tension tests were carried out on AS4/PEEK [ 0/+/- 45/90 ]2s composites. When AS4/PEEK composite laminates were deformed, the images of natural surface of the AS4/PEEK specimen were recorded to study the damage initiation and growth. The experimental results show that the considerable interlaminal stresses between different plies, and these places were more prone to delaminate. The paper presents the microscopic damages and matrix crack growth observed by an optical microscope and the CCD camera.

  5. Heat splicing of plastic fibers using a PEEK tube

    NASA Astrophysics Data System (ADS)

    Hara, K.; Horiuchi, K.; Kim, S.; Nakano, I.; Takebayashi, T.; Takikawa, K.; Yasuoka, K.; Koyano, M.; Matsui, S.; Takeuchi, H.

    1994-08-01

    We have developed a device to splice plastic optical fibers by thermal fusion. The device heats the joint of fibers inserted in a PEEK tube, which can help align the fiber axes and protects the fused joint mechanically. We have tuned the device to produce splices with good light transmission and mechanical strength. Light transmission of nearly 95% with an rms variation of 1.5% has been achieved. The joint supports 1.2 kgf in tension and the bending radius can be as small as 3 cm. The mechanical strength can be improved easily by adding epoxy. We describe the optimization of the device and measurement results of 28000 fiber splices for the CDF plug-upgrade tile/fiber calorimeter.

  6. On compression and damage evolution in PTFE and PEEK

    NASA Astrophysics Data System (ADS)

    Rau, C.; Parry, S.; Garcea, S. C.; Bourne, N. K.; McDonald, S. A.; Eastwood, D. S.; Brown, E. N.; Withers, P. J.

    2017-01-01

    The well-known Taylor cylinder impact test, that follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, PTFE and PEEK. In previous work experiments and a model were developed to capture the deformation behaviour of the rod after impact. A distinctive feature of these works was that a region in which both spatial and temporal variation of both longitudinal and radial deformation showed evidence of changes in phase within the material. This region is X-ray imaged in a range of impacted targets at the I13 Imaging and Coherence beam line at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. This shows the transit of damage from ductile to brittle failure results from previously undetected internal failure.

  7. Cold-spray coating of hydroxyapatite on a three-dimensional polyetheretherketone implant and its biocompatibility evaluated by in vitro and in vivo minipig model.

    PubMed

    Lee, Jae Hyup; Jang, Hae Lin; Lee, Kyung Mee; Baek, Hae-Ri; Jin, Kyoungsuk; Noh, Jun Hong

    2017-04-01

    PEEK is a bioinert material that does not chemically bind to native bone tissue and thus formation of natural bone-like hydroxyapatite (HA) coating layer on PEEK has been an important challenge to improve biocompatibility and to preserve mechanical property of PEEK. Among various coating techniques, cold-spray coating method is suitable to form stable HA coating layer on PEEK while maintaining their chemical properties, because it can be conducted in relatively low-temperature range. Therefore, in this research, we used cold-spray coating method to form a thick layer of HA on the topographically complex PEEK substrates with periodic ridges on the surface and implanted in iliac bone defects of minipigs which is known to be similar with human body system. In addition, PEEK cage for clinical usage was coated with HA and inserted in the lumbar intervertebral disc space of minipig. We observed higher ALP activity, calcium production, and BSP production of human bone marrow mesenchymal stem cells on the HA-coated PEEK implants than the bare PEEK group in in vitro test. In addition, two-dimensional histological analysis and three-dimensional micro CT analysis demonstrated that implantation of complex shape of HA-PEEK hybrid implant in in vivo minipig model resulted sufficient biocompatibility and osseointegration for further clinical applications. Notably, due to the enhanced stability of PEEK cage induced from HA coating layer, osseointegration rate of the small HA blocks loaded inside the PEEK cage was also significantly improved which indicates overall increased fusion rate and adherence of the HA-coated PEEK cage. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 647-657, 2017. © 2015 Wiley Periodicals, Inc.

  8. Suitability of carbon fiber-reinforced polyetheretherketone cages for use as anterior struts following corpectomy.

    PubMed

    Heary, Robert F; Parvathreddy, Naresh K; Qayumi, Zainab S; Ali, Naiim S; Agarwal, Nitin

    2016-08-01

    OBJECTIVE Fibular allograft remains a widely used strut for corpectomy surgeries. The amount of graft material that can be packed into an allograft strut has not been quantified. Cages are an alternative to fibular allograft for fusion surgeries. The authors of this study assessed the suitability of carbon fiber-reinforced polyetheretherketone (CFRP) cages for anterior corpectomy surgeries. They further explored the parameters known to affect fusion rates in clinical practice. METHODS Six fibular allografts were tested at standard lengths. Three sets of carbon fiber cages (Bengal, DePuy Spine), each with a different footprint size but the same lengths, were tested. The allografts and cages were wrapped in adhesive, fluid-tight transparent barriers and filled with oil. The volume and weight of the oil instilled as well as the implant footprints were measured. The fibular allografts and cages were tested at 20-, 40-, and 50-mm lengths. Two investigators independently performed all measurements 5 times. Five CFRP cubes (1 × 1 × 1 cm) were tested under pure compression, and load versus displacement curves were plotted to determine the modulus of elasticity. RESULTS Significantly more oil fit in the CFRP cages than in the fibular allografts (p < 0.0001). The weight and volume of oil was 4-6 times greater in the cages. Interobserver (r = 0.991) and intraobserver (r = 0.993) reliability was excellent. The modulus of elasticity for CFRP was 16.44 ± 2.07 GPa. CONCLUSIONS Carbon fiber-reinforced polyetheretherketone cages can accommodate much more graft material than can fibular allografts. In clinical practice, the ability to deliver greater amounts of graft material following a corpectomy may improve fusion rates.

  9. Cervical polyps

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/001494.htm Cervical polyps To use the sharing features on this page, please enable JavaScript. Cervical polyps are fingerlike growths on the lower part ...

  10. Cervical Cancer

    MedlinePlus

    ... the place where a baby grows during pregnancy. Cervical cancer is caused by a virus called HPV. ... for a long time, or have HIV infection. Cervical cancer may not cause any symptoms at first. ...

  11. Wear rate control of peek surfaces modified by femtosecond laser

    NASA Astrophysics Data System (ADS)

    Hammouti, S.; Pascale-Hamri, A.; Faure, N.; Beaugiraud, B.; Guibert, M.; Mauclair, C.; Benayoun, S.; Valette, S.

    2015-12-01

    This paper presents the effect of laser texturing on the tribological properties of PEEK surfaces under a ball-on-flat contact configuration. Thus, surfaces with circular dimples of various diameters and depth were created. Tests were conducted with a normal load of 5 N and a sliding velocity of 0.01 m s-1, using bovine calf serum at 37.5 °C as a lubricant. The tribological conditions including the sliding frequency and the lubricant viscosity indicate that tests were performed under boundary lubrication regime. Results showed that discs with higher dimple depth exhibited higher friction coefficient and caused more abrasive wear on the ball specimen. Nevertheless, tribosystems (ball and disc) with dimpled disc surfaces showed a higher wear resistance. In the frame of our experiments, wear rates obtained for tribosystems including dimpled surfaces were 10 times lower than tribosystems including limited patterned or untextured surfaces. Applications such as design of spinal implants may be concerned by such a surface treatment to increase wear resistance of components.

  12. Mechanical property characterization and impact resistance of selected graphite/PEEK composite materials

    NASA Technical Reports Server (NTRS)

    Baker, Donald J.

    1991-01-01

    To use graphite/PEEK material on highly curved surfaces requires that the material be drapable and easily conformable to the surface. The mechanical property characterization and impact resistance results are presented for laminates made from two types of graphite/PEEK materials that will conform to a curved surface. These laminates were made from two different material forms. These forms are: (1) a fabric where each yarn is a co-mingled Celion G30-500 3K graphite fiber and PEEK fiber; and (2) an interleaved material of Celion G30-500 3K graphite fiber interleaved with PEEK film. The experimental results from the fabric laminates are compared with results for laminates made from AS4/PEEK unidirectional tape. The results indicate that the tension and compression moduli for quasi-isotropic and orthotropic laminates made from fabric materials are at least 98 pct. of the modulus of equivalent laminates made from tape materials. The strength of fabric material laminates is at least 80 pct. of laminates made from tape material. The evaluation of the fabric material for shear stiffness indicates that a tape material laminate could be replaced by a fabric material laminate and still maintain 89 pct. of the shear stiffness of the tape material laminate.

  13. Structural refinement and DSC characterization of PEEK fiber. [Poly(aryletheretherketone)

    SciTech Connect

    Fratini, A.V.; Cross, E.M.; Whitaker, R.B.

    1986-06-03

    The crystalline structure of oriented fibers of poly(aryletheretherketone) (PEEK) has been analyzed by x-ray diffraction and refined by the Linked-Atom Least-Squares procedure. The conformation of chains, consisting of a six-aryl ring unit, is approximated by the refinement of a two-aryl ring unit within the orthorhombic unit subcell with dimensions: a = 7.83 +- 0.02 A, b = 5.94 +- 0.01 A, and c = 9.86 +- 0.04 A. Certain constraints imposed by Pbcn space group symmetry are relaxed during refinement. The results of the two-ring refinement indicate that a single torsion angle can be used to describe the conformation of the six-ring unit. The torsion angle corresponds to the average tilt of the phenylene rings out of the (100) face, and the best fit is obtained with an angle of 37/sup 0/. The simulated powder diffraction pattern based on the atomic coordinates of the six-ring unit matches very closely previously reported patterns for a variety of PEEK specimens. The analysis supports, and extends to oriented fibers, the previously reported finding that space group Pbcn is a valid representation for the structure of PEEK. Differential scanning calorimetry established that the PEEK samples were typical PEEK material.

  14. Cervical Cancer

    MedlinePlus

    ... cervical cancers are caused by the human papillomavirus (HPV). Cervical cancer is the easiest gynecological cancer to prevent with ... HPV on a woman's cervix. Certain types of HPV can lead to cervical cancer. Your doctor will swab the cervix for cells. ...

  15. Kinematics and load-sharing of an anterior thoracolumbar spinal reconstruction construct with PEEK rods: An in vitro biomechanical study.

    PubMed

    Zhou, Ruozhou; Huang, Zhiping; Liu, Xiang; Tong, Jie; Ji, Wei; Liu, Sheting; Zhu, Qingan

    2016-12-01

    Polyetheretherketone rod constructs provide adequate spinal stability. Kinematics and load sharing of anterior thoracolumbar reconstruction with polyetheretherketone rods under preload remains unknown. Eight human cadaveric specimens (T11-L3) were subjected to a pure moment of 5.0Nm in flexion-extension, lateral bending and axial rotation, and flexion-extension with a compressive preload of 300N. An anterior reconstruction of L1 corpectomy was conducted with a surrogate bone graft and anterior rod constructs (polyetheretherketone or titanium rods). An axial load-cell was built in the surrogate bone graft to measure the compressive force in the graft. Range of motion, neutral zone and compressive force in the graft were compared between constructs. The polyetheretherketone rod construct resulted in more motion than the titanium rod construct, particularly in extension (P=0.011) and axial rotation (P=0.001), but less motion than the intact in all directions except in axial rotation. There was no difference in range of motion or neutral zone between constructs in flexion-extension under preload. The polyetheretherketone rod construct kept the graft compressed 52N which was similar to the titanium rod construct (63N), but allowed the graft compressed more under the preload (203N vs. 123N, P=0.003). The compressive forces fluctuated in flexion-extension without preload, but increased in flexion and decreased in extension under preload. The polyetheretherketone rod construct allowed more motion compared to the titanium rod construct, but provided stability in flexion and lateral bending without preload, and flexion and extension under preload. The anterior graft shared higher load under preload, particularly for the polyetheretherketone rod construct. The results of this study suggest that rigidity of rods in the anterior reconstruction affects kinematic behavior and load sharing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Feasibility of Carbon Fiber/PEEK Composites for Cryogenic Fuel Tank Applications

    NASA Astrophysics Data System (ADS)

    Doyle, K.; Doyle, A.; O Bradaigh, C. M.; Jaredson, D.

    2012-07-01

    This paper investigates the feasibility of CF/PEEK composites for manufacture of cryogenic fuel tanks for Next Generation Space Launchers. The material considered is CF/PEEK tape from Suprem SA and the proposed manufacturing process for the fuel tank is Automated Tape Placement. Material characterization was carried out on test laminates manufactured in an autoclave and also by Automated Tape Placement with in-situ consolidation. The results of the two processes were compared to establish if there is any knock down in properties for the automated tape placement process. A permeability test rig was setup with a helium leak detector and the effect of thermal cycling on the permeability properties of CF/PEEK was measured. A 1/10th scale demonstrator was designed and manufactured consisting of a cylinder manufactured by automated tape placement and an upper dome manufactured by autoclave processing. The assembly was achieved by Amorphous Interlayer Bonding with PEI.

  17. Effect of polyimide interphase on impact and fatigue properties of PEEK/carbon fiber composites

    SciTech Connect

    Davis, R.M.; Gardner, S.H.; Gonzalez, A.

    1995-12-01

    There is a growing interest in carbon fiber reinforced thermoplastic composites. Aqueous suspension prepregging is a new prepregging technique which provides a method for manufacturing PEEK/carbon fiber composites. This method also allows systematic variance of the properties of the interphase region between the carbon fiber and the bulk matrix. It has been found that this interphase region has a effect on dynamic mechanical properties. Notched fatigue testing and impact testing have been used to illustrate the effect of this interphase region. Notched fatigue testing is sensitive to the strength of the fiber-matrix bond. Through these mechanical tests it has been shown that PEEK composites made with a BisP-BTDA binder have a stronger fiber-matrix bond than a reference composite made from APC-2. PEEK composites made with a LaRC TPI binder also have a stronger fiber-matrix bond than APC-2.

  18. A comparative study of radiation effects in medical-grade polymers: UHMWPE, PCU and PEEK

    NASA Astrophysics Data System (ADS)

    Jahan, Muhammad S.; Walters, Benjamin M.; Riahinasab, Tayebeh; Gnawali, Rudra; Adhikari, Dipendra; Trieu, Hai

    2016-01-01

    In this study, three medical-grade polymers, ultra-high molecular weight polyethylene (UHMWPE), polycarbonate urethane (PCU) and poly (ether ether ketone) PEEK, were tested immediately after x-irradiation. The primary purpose of this study was to provide a qualitative comparison of the radiation-sensitivity of these polymers. To evaluate radiation-induced defects or trapped charges, radiation dosimetry method, known as thermally stimulated luminescence (TSL) or thermoluminescence (TL), was employed, and for free radical comparison, electron spin resonance (ESR) was used. When these polymers were x-irradiated at room temperature and subsequently heated, broad luminescence was detected as a function of temperature (known as a glow curve) in the temperature region of 75 °C to 250 °C. In particular, TSL of PCU exhibited glow peaks near 140 °C and 225 °C, that of PEEK near 100 °C and 150 °C, and of UHMWPE near 100 °C and 140 °C. In each case, totalTSL was found to increase as a function of x-ray exposure, suggesting the production of radiation-induced species in the respective polymer matrix. Compared to PCU or PEEK, UHMWPE was found to form more than one order of magnitude of free radicals per unit mass per unit x-ray exposure. In two hours in air at room temperature after irradiation, UHMWPE lost 42% of its initial radical concentration, while PCU lost 75%. X-ray induced PEEK radicals (peroxy/phenoxy) decayed in about one week. Unlike UHMWPE or PCU, non-irradiated (as-received) PEEK was found to contain residual radicals. In UHMWPE, primary radicals reportedly decay to oxygen-centered polyenyl radicals in about three months. In all the results did find significant radical formation via ESR and supporting radiation sensitivity measurements via TSL, warranting further investigation into the effects of radiation on PEEK and PCU.

  19. Processing-structure-property relations in PEEK/carbon composites made from comingled fabric and prepreg

    SciTech Connect

    Vu-khanh, T.; Denault, J. )

    1991-10-01

    The effects of the conditions of the processing of PEEK/carbon prepregs and comingled fabric on the microstructure and mechanical characteristics of the resulting composites were investigated. Results showed that, in the comingled fabric system, the fiber/matrix adhesion depends on the molding temperature, the residence time at the melt temperature, and the cooling rate. Too high molding temperature resulted in degradation of the PEEK matrix, which affected the crystallization behavior of the composites, the fiber/matrix adhesion, and the matrix properties. This effect was most important in the case of comingled systems containing sized carbon fibers. 17 refs.

  20. Electrical resistance of CNT-PEEK composites under compression at different temperatures

    PubMed Central

    2011-01-01

    Electrically conductive polymers reinforced with carbon nanotubes (CNTs) have generated a great deal of scientific and industrial interest in the last few years. Advanced thermoplastic composites made of three different weight percentages (8%, 9%, and 10%) of multiwalled CNTs and polyether ether ketone (PEEK) were prepared by shear mixing process. The temperature- and pressure-dependent electrical resistance of these CNT-PEEK composites have been studied and presented in this paper. It has been found that electrical resistance decreases significantly with the application of heat and pressure. PMID:21711952

  1. Multilevel surface engineering of nanostructured TiO2 on carbon-fiber-reinforced polyetheretherketone.

    PubMed

    Lu, Tao; Liu, Xuanyong; Qian, Shi; Cao, Huiliang; Qiao, Yuqin; Mei, Yongfeng; Chu, Paul K; Ding, Chuanxian

    2014-07-01

    As an implantable material, carbon-fiber-reinforced polyetheretherketone (CFRPEEK) possesses an adjustable elastic modulus similar to that of cortical bone and is a prime candidate to replace metallic surgical implants. However, the bioinertness and poor osteogenic properties of CFRPEEK limit its clinical application as orthopedic implants. In this work, titanium ions are introduced energetically into CFRPEEK by plasma immersion ion implantation (PIII). Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) reveal the formation of nanopores with the side wall and bottom embedded with ∼20 nm TiO2 nanoparticles on the CFRPEEK surface. Nanoindentation measurements confirm the stability and improved elastic resistance of the structured surfaces. In vitro cell adhesion, viability assay, and real-time PCR analyses disclose enhanced adhesion, proliferation, and osteo-differentiation of rat bone mesenchymal stem cells (bMSCs). The multilevel structures on CFRPEEK also exhibit partial antibacterial activity to Staphylococcus aureus and Escherichia coli. Our results indicate that a surface with multifunctional biological properties can be produced by multilevel surface engineering and application of CFRPEEK to orthopedic and dental implants can be broadened and expedited based on this scheme.

  2. Cervical Angina

    PubMed Central

    Sussman, Walter I.; Makovitch, Steven A.; Merchant, Shabbir Hussain I.

    2015-01-01

    Cervical angina has been widely reported as a cause of chest pain but remains underrecognized. This series demonstrates the varied clinical presentation of patients with cervical angina, the delay in diagnosis, and the extensive cardiac examinations patients with this condition typically undergo prior to a definitive diagnosis. Recognition of this condition in patients with acute chest pain requires a high index of suspicion and an awareness of the common presenting features and clinical findings of cervical angina. PMID:25553225

  3. Real time SAXS studies of lamellar level morphological development in PEEK

    SciTech Connect

    Verma, R.K.; Marand, H.; Chu, B.

    1995-12-01

    The double endotherm melting behavior of poly(aryl ether ether ketone) PEEK has been the subject of considerable debate during the last few years. Most authors are of the opinion that this behavior is caused either by a melting-recrystallization phenomenon or by the presence of two populations of lamellar thicknesses. In this paper, the double endothermic behavior of PEEK is studied using real time small angle X-ray scattering (SAXS). The correlation and interface distribution functions were used to analyze SAXS data. Calculations presented in this paper suggest that the semi-crystalline morphology of PEEK consists of two type of lamellar stacks consistent with primary and secondary crystallization. The lamellar thickness within these 2 stacks are observed to be about 70 A and 120 A (secondary and primary lamellae respectively) for PEEK crystallized at 307{degrees}C. Based on these observations, we speculate the that double endotherm melting behavior might be related to the melting of these dual stacks of lamellae.

  4. Deposition, Heat Treatment And Characterization of Two Layer Bioactive Coatings on Cylindrical PEEK

    PubMed Central

    Durham, John W.; Rabiei, Afsaneh

    2015-01-01

    Polyether ether ketone (PEEK) rods were coated via ion beam asssited deposition (IBAD) at room temperature. The coating consists of a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to increase bioactivity. A rotating substrate holder was designed to deposit an even coating on the cylindrical surface of PEEK rods; the uniformity is verified by cross-sectional measurements using scanning electron microscopy (SEM). Deposition is followed by heat treatment of the coating using microwave annealing and autoclaving. Transmission electron microscopy (TEM) showed a dense, uniform columnar grain structure in the YSZ layer that is well bonded to the PEEK substrate, while the calcium phosphate layer was amorphous and pore-free in its as-deposited state. Subsequent heat treatment via microwave energy introduced HA crystallization in the calcium phosphate layer and additional autoclaving further expanded the crystallization of the HA layer. Chemical composition evaluation of the coating indicated the Ca/P ratios of the HA layer to be near that of stoichiometric HA, with minor variations through the HA layer thickness. The adhesion strength of as-deposited HA/YSZ coatings on smooth, polished PEEK surfaces was mostly unaffected by microwave heat treatment, but decreased with additional autoclave treatment. Increasing surface roughness showed improvement of bond strength. PMID:27713592

  5. MushyPeek: A Framework for Online Investigation of Audiovisual Dialogue Phenomena

    ERIC Educational Resources Information Center

    Edlund, Jens; Beskow, Jonas

    2009-01-01

    Evaluation of methods and techniques for conversational and multimodal spoken dialogue systems is complex, as is gathering data for the modeling and tuning of such techniques. This article describes MushyPeek, an experiment framework that allows us to manipulate the audiovisual behavior of interlocutors in a setting similar to face-to-face…

  6. Inflammatory response against different carbon fiber-reinforced PEEK wear particles compared with UHMWPE in vivo.

    PubMed

    Utzschneider, Sandra; Becker, Fabian; Grupp, Thomas M; Sievers, Birte; Paulus, Alexander; Gottschalk, Oliver; Jansson, Volkmar

    2010-11-01

    Poly(ether ether ketone) (PEEK) and its composites are recognized as alternative bearing materials for use in arthroplasty because of their mechanical properties. The objective of this project was to evaluate the biological response of two different kinds of carbon fiber-reinforced (CFR) PEEK compared with ultra-high molecular weight polyethylene (UHMWPE) in vivo as a standard bearing material. Wear particles of the particulate biomaterials were injected into the left knee joint of female BALB/c mice. Assessment of the synovial microcirculation using intravital fluorescence microscopy as well as histological evaluation of the synovial layer were performed 7 days after particle injection. Enhanced leukocyte-endothelial cell interactions and an increase in functional capillary density as well as histological investigations revealed that all tested biomaterials caused significantly (P < 0.05) increased inflammatory reactions compared with control animals (injected with sterile phosphate-buffered saline), without any difference between the tested biomaterials (P > 0.05). These data suggest that wear debris of CFR-PEEK is comparable with UHMWPE in its biological activity. Therefore, CFR-PEEK represents an alternative bearing material because of its superior mechanical and chemical behavior without any increased biological activity of the wear particles, compared with a standard bearing material.

  7. MushyPeek: A Framework for Online Investigation of Audiovisual Dialogue Phenomena

    ERIC Educational Resources Information Center

    Edlund, Jens; Beskow, Jonas

    2009-01-01

    Evaluation of methods and techniques for conversational and multimodal spoken dialogue systems is complex, as is gathering data for the modeling and tuning of such techniques. This article describes MushyPeek, an experiment framework that allows us to manipulate the audiovisual behavior of interlocutors in a setting similar to face-to-face…

  8. Deposition, Heat Treatment And Characterization of Two Layer Bioactive Coatings on Cylindrical PEEK.

    PubMed

    Durham, John W; Rabiei, Afsaneh

    2016-09-15

    Polyether ether ketone (PEEK) rods were coated via ion beam asssited deposition (IBAD) at room temperature. The coating consists of a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to increase bioactivity. A rotating substrate holder was designed to deposit an even coating on the cylindrical surface of PEEK rods; the uniformity is verified by cross-sectional measurements using scanning electron microscopy (SEM). Deposition is followed by heat treatment of the coating using microwave annealing and autoclaving. Transmission electron microscopy (TEM) showed a dense, uniform columnar grain structure in the YSZ layer that is well bonded to the PEEK substrate, while the calcium phosphate layer was amorphous and pore-free in its as-deposited state. Subsequent heat treatment via microwave energy introduced HA crystallization in the calcium phosphate layer and additional autoclaving further expanded the crystallization of the HA layer. Chemical composition evaluation of the coating indicated the Ca/P ratios of the HA layer to be near that of stoichiometric HA, with minor variations through the HA layer thickness. The adhesion strength of as-deposited HA/YSZ coatings on smooth, polished PEEK surfaces was mostly unaffected by microwave heat treatment, but decreased with additional autoclave treatment. Increasing surface roughness showed improvement of bond strength.

  9. Hubbert's Peek: Looking at the Future of Oil

    NASA Astrophysics Data System (ADS)

    Deffeyes, K. S.

    2002-05-01

    After M. King Hubbert initially predicted in 1956 that U.S. oil production would peak in the early 1970s, he continued to refine his methodology. In addition to annual oil production, Hubbert used cumulative "discoveries", defined as the cumulative amount of oil produced up to a given year plus the known reserves as of that same year. Because oil is added to the reserves several years before it is produced, the use of discoveries allowed Hubbert to peek farther into the future. Hubbert utilized the simplest hypothesis that might fit the observations: 1) annual production would fit a symmetrical bell-shaped curve, and 2) discoveries would follow an identical bell curve, earlier in time by a fixed number of years. There were four free parameters in the fit: the annual production at the peak, the width (at half height) of the curve, the year of peak production, and the peak year of discoveries. In 1982, when he was 79 years old, Hubbert published a long paper justifying his choice of the logistic bell curve, rather than the more familiar Gaussian. He pointed out that the differential equation underlying the logistic curve could be interpreted as an annual growth rate that depends linearly on the fraction of oil remaining undiscovered. The logistic differential equation could be rearranged into a linear form that turned a logistic curve into a straight line. (Hubbert did not mention that population biologists had been using the same straight-line graph.) In 2001, I showed that both the production and discovery data could be plotted together on the same graph. An interesting puzzle arose: fitting the bell-shaped curves required four free parameters, but a straight line has only two free parameters. It turns out that the center year for production, and for discoveries, are found only indirectly from the straight-line graph. Almost all economists reject the entire Hubbert analysis because the effect of oil prices on exploration effort and production methods is ignored

  10. Assessment of epidural versus intradiscal biocompatibility of PEEK implant debris: an in vivo rabbit model.

    PubMed

    Hallab, Nadim J; Bao, Qi-Bin; Brown, Tim

    2013-12-01

    To understand the relative histopathological effects of PEEK particulate debris when applied within the epidural versus the intervertebral disc space. We hypothesized that due to the avascular nature of the intervertebral disc acting as a barrier to immune cells, the intradiscal response would be less than the epidural response. The inflammatory effects of clinically relevant doses (3 mg/5-kg rabbit) and sizes (1.15 µm diameter) of PEEK implant debris were assed when placed dry on epidural and intradiscal tissues in an in vivo rabbit model. The size of the particulate was based on wear particulate analysis of wear debris generated from simulator wear testing of PEEK spinal disc arthroplasty devices. Local and systemic gross histology was evaluated at the 3- and 6-month time points. Quantitative immunohistochemistry of local tissues was used to quantify the common inflammatory mediators TNF-α, IL-1β, and IL-6. Both treatments did not alter the normal appearance of the dura mater and vascular structures; however, limited epidural fibrosis was observed. Epidural challenge of PEEK particles resulted in a significant (30 %) increase (p < 0.007) in TNF-α and IL-1β at both 3 and 6 months compared to that of controls, and IL-6 at 6 months (p < 0.0001). Intradiscal challenge of PEEK particles resulted in a significant increase in IL-1β, IL-6 and TNF-α at 6-months post-challenge (p ≤ 0.03). However, overall there were only moderate increases in the relative amount of these cytokines when compared with surgical controls (10-20 %). In contrast, epidural challenge resulted in a 50-100 % increase. The results of this study are similar to past investigations of PEEK, whose results have not been shown to elicit an aggressive immune response. The degree to which these results will translate to the clinical environment remains to be established, but the pattern of subtle elevations in inflammatory cytokines indicated both a mild persistence of responses to PEEK debris, and

  11. The improvement of adhesive properties of PEEK through different pre-treatments

    NASA Astrophysics Data System (ADS)

    Hallmann, Lubica; Mehl, Albert; Sereno, Nuno; Hämmerle, Christoph H. F.

    2012-07-01

    The purpose of this in vitro study was the evaluation of the bond strength of the adhesives/composite resin to Poly Ether Ether Ketone (PEEK) based dental polymer after using different surface conditioning methods. PEEK blanks were cut into discs. All disc specimens were polished with 800 grit SiC paper and divided into 6 main groups. Main groups were divided into 2 subgroups. The main groups of 32 specimens each were treated as follow: (1) control specimens (no treatment), (2) piranha solution etching, (3) abraded with 50 μm alumina particles and chemical etching, (4) abraded with 110 μm alumina particles and chemical etching, (5) abraded with 30 μm silica-coated alumina particles and chemical etching, (6) abraded with 110 μm silica-coated alumina particles and chemical etching. Plexiglas tubes filled with a composite resin (RelyX Unicem) were bonded to the specimens. The adhesives used were Heliobond and Clearfil Ceramic Primer. Each specimen was stored in distilled water (37 °C) for 3 days. Tensile bond strength was measured in a universal testing machine and failure methods were evaluated. Abraded surface with 50 μm alumina particles followed by etching with piranha solution lead to the highest bond strength of 21.4 MPa when Heliobond like adhesive was used. Tribochemical silica coated/etched PEEK surfaces did not have an effect on the bond strength. Non-treated PEEK surface was not able to establish a bond with composite resin. The proper choice of adhesive/composite resin system leads to a strong bond. ConclusionAirborne particle abrasion in combination with piranha solution etching improves the adhesive properties of PEEK.

  12. Subsidence of polyetheretherketone intervertebral cages in minimally invasive lateral retroperitoneal transpsoas lumbar interbody fusion.

    PubMed

    Le, Tien V; Baaj, Ali A; Dakwar, Elias; Burkett, Clinton J; Murray, Gisela; Smith, Donald A; Uribe, Juan S

    2012-06-15

    A retrospective review. The objective is to evaluate subsidence related to minimally invasive lateral retroperitoneal lumbar interbody fusion by reviewing our experience with this procedure. Polyetheretherketone intervertebral cages of different lengths, widths, and heights filled with various allograft types are commonly used as spacers in lumbar fusions. Subsidence is a potential complication. To date, there are no published reports specifically addressing subsidence, because it relates to a series of patients undergoing minimally invasive lateral retroperitoneal transpsoas lumbar interbody fusion. An institutional review board-approved, retrospective review of a prospectively collected database was conducted. One hundred forty consecutive patients who underwent this procedure between L1 and L5 during a 2-year period were included. All patients had T scores of -2.5 or more. Postoperative radiographs during routine follow-ups were reviewed for subsidence, defined as any violation of the vertebral end plate. Radiographical subsidence occurred in 14.3% (20 of 140), whereas clinical subsidence occurred in 2.1%. Subsidence occurred in 8.8% (21 of 238) of levels fused. Construct length had a significant positive correlation with increasing subsidence rates. Subsidence rates decreased progressively with lower levels in the lumbar spine, but had a higher than expected rate at L4-L5. Subsidence rates of 14.1% (19 of 135) and 1.9% (2 of 103) were associated with 18-and 22-mm-wide cages, respectively. No significant trends were observed with cage lengths. Supplemental lateral plates had a higher rate of subsidence than bilateral pedicle screws. Subsidence occurred at the superior end plate 70% of the time. The use of wider intervertebral cages leads to a significantly lower rate of subsidence, but a longer cage does not necessarily offer a similar advantage. Wide cages are protective against subsidence, and the widest cages should be used whenever feasible for interbody

  13. HUBBLE PEEKS INTO A STELLAR NURSERY IN A NEARBY GALAXY

    NASA Technical Reports Server (NTRS)

    2002-01-01

    HUBBLE PEEKS INTO A STELLAR NURSERY IN A NEARBY GALAXY NASA's Hubble Space Telescope has peered deep into a neighboring galaxy to reveal details of the formation of new stars. Hubble's target was a newborn star cluster within the Small Magellanic Cloud, a small galaxy that is a satellite of our own Milky Way. The new images show young, brilliant stars cradled within a nebula, or glowing cloud of gas, cataloged as N 81. These massive, recently formed stars inside N 81 are losing material at a high rate, sending out strong stellar winds and shock waves and hollowing out a cocoon within the surrounding nebula. The two most luminous stars, seen in the Hubble image as a very close pair near the center of N 81, emit copious ultraviolet radiation, causing the nebula to glow through fluorescence. Outside the hot, glowing gas is cooler material consisting of hydrogen molecules and dust. Normally this material is invisible, but some of it can be seen in silhouette against the nebular background, as long dust lanes and a small, dark, elliptical-shaped knot. It is believed that the young stars have formed from this cold matter through gravitational contraction. Few features can be seen in N 81 from ground-based telescopes, earning it the informal nick-name 'The Blob.' Astronomers were not sure if just one or a few hot stars were embedded in the cloud, or if it was a stellar nursery containing a large number of less massive stars. Hubble's high-resolution imaging shows the latter to be the case, revealing that numerous young, white-hot stars---easily visible in the color picture---are contained within N 81. This crucial information bears strongly on theories of star formation, and N 81 offers a singular opportunity for a close-up look at the turbulent conditions accompanying the birth of massive stars. The brightest stars in the cluster have a luminosity equal to 300,000 stars like our own Sun. Astronomers are especially keen to study star formation in the Small Magellanic

  14. Cervical pneumatocyst.

    PubMed

    Hoover, Jason M; Wenger, Doris E; Eckel, Laurence J; Krauss, William E

    2011-09-01

    The authors present the case of a 56-year-old right hand-dominant woman who was referred for chronic neck pain and a second opinion regarding a cervical lesion. The patient's pain was localized to the subaxial spine in the midline. She reported a subjective sense of intermittent left arm weakness manifesting as difficulty manipulating small objects with her hands and fingers. She also reported paresthesias and numbness in the left hand. Physical and neurological examinations demonstrated no abnormal findings except for a positive Tinel sign over the left median nerve at the wrist. Electromyography demonstrated bilateral carpal tunnel syndrome with no cervical radiculopathy. Cervical spine imaging demonstrated multilevel degenerative disc disease and a pneumatocyst of the C-5 vertebral body. The alignment of the cervical spine was normal. A review of the patient's cervical imaging studies obtained in 1995, 2007, 2008, and 2010 demonstrated that the pneumatocyst was not present in 1995 but was present in 2007. The lesion had not changed in appearance since 2007. At an outside institution, multilevel fusion of the cervical spine was recommended to treat the pneumatocyst prior to evaluation at the authors' institution. The authors, however, did not think that the pneumatocyst was the cause of the patient's neck pain, and cervical pneumatocysts typically have a benign course. As such, the authors recommended conservative management and repeated MR imaging in 6 months. Splinting was used to treat the patient's carpal tunnel syndrome.

  15. Cervical cancer

    MedlinePlus

    ... therapy: Uses light to burn abnormal tissue A hysterectomy (surgery to remove the uterus but not the ... for more advanced cervical cancer may include: Radical hysterectomy, which removes the uterus and much of the ...

  16. Cervical Cap

    MedlinePlus

    ... and remove the cap. How Much Does It Cost? A cervical cap costs about $70 and should be replaced every year. In addition, there is also the cost of the doctor's visit. Many health insurance plans ...

  17. Cervical Stenosis

    MedlinePlus

    ... Dictionary Also of Interest (Quiz) Overview of the Female Reproductive System (Video) Cervical Dysplasia (News) Antiperspirant Use Seems Safe ... version Also of Interest Test your knowledge The female reproductive system consists of the external and internal genital organs. ...

  18. Cervical Myomas

    MedlinePlus

    ... Dictionary Also of Interest (Quiz) Overview of the Female Reproductive System (Video) Cervical Dysplasia (News) Antiperspirant Use Seems Safe ... version Also of Interest Test your knowledge The female reproductive system consists of the external and internal genital organs. ...

  19. Cervical Cap

    MedlinePlus

    ... Staff The cervical cap is a birth control (contraceptive) device that prevents sperm from entering the uterus. ... more times a week, you've had previous contraceptive failure with vaginal barrier methods or you're ...

  20. Cervical dysplasia

    MedlinePlus

    ... by your provider. Make sure to get the HPV vaccine when it is offered to you. This vaccine ... Ask your provider about the HPV vaccine . Girls who receive this ... their chance of getting cervical cancer. You can reduce your ...

  1. Cervical spondylosis

    MedlinePlus

    Cervical osteoarthritis; Arthritis - neck; Neck arthritis; Chronic neck pain; Degenerative disk disease ... nonsteroidal anti-inflammatory medicines (NSAIDs) for long-term pain control. Opioids may be prescribed if the pain is severe ...

  2. Cervical Cerclage

    MedlinePlus

    ... cerclage). Typically, the stitches are removed at around week 37 of pregnancy. Your health care provider might ... prior spontaneous premature birth at less than 34 weeks, and, upon ultrasound exam, a short cervical length ( ...

  3. Influence of PEEK Coating on Hip Implant Stress Shielding: A Finite Element Analysis

    PubMed Central

    Anguiano-Sanchez, Jesica; Martinez-Romero, Oscar; Siller, Hector R.; Diaz-Elizondo, Jose A.; Flores-Villalba, Eduardo

    2016-01-01

    Stress shielding is a well-known failure factor in hip implants. This work proposes a design concept for hip implants, using a combination of metallic stem with a polymer coating (polyether ether ketone (PEEK)). The proposed design concept is simulated using titanium alloy stems and PEEK coatings with thicknesses varying from 100 to 400 μm. The Finite Element analysis of the cancellous bone surrounding the implant shows promising results. The effective von Mises stress increases between 81 and 92% for the complete volume of cancellous bone. When focusing on the proximal zone of the implant, the increased stress transmission to the cancellous bone reaches between 47 and 60%. This increment in load transferred to the bone can influence mineral bone loss due to stress shielding, minimizing such effect, and thus prolonging implant lifespan. PMID:27051460

  4. Improving adhesion of powder coating on PEEK composite: Influence of atmospheric plasma parameters

    NASA Astrophysics Data System (ADS)

    Dupuis, Aurélie; Ho, Thu Huong; Fahs, Ahmad; Lafabrier, Aurore; Louarn, Guy; Bacharouche, Jalal; Airoudj, Aissam; Aragon, Emmanuel; Chailan, Jean-François

    2015-12-01

    In aeronautic industries, powder coatings are increasingly used because of environmental considerations. During the deposition of such a coating on a substrate piece, the main objective is to obtain a good coating/substrate adhesion. In this study, the targeted substrate is a Poly-(Ether EtherKetone)-(PEEK) based composite material. Due to the poor surface energy of PEEK, a surface treatment is necessary in order to enhance its adhesion with the coating. In this purpose, atmospheric plasma treatment has been chosen and the influence of plasma parameters has been studied. Four scan speed nozzles and three gases (Air, N2 and Argon) plasma has been tested. The increase of adhesion with increasing wettability, polarity and nanoroughness has been evidenced. A particular study of the type of grafted polar functionalities according to gas nature allowed to better understand the plasma mechanism and the cross-impact of polarity and nanoroughness in adhesion enhancement.

  5. Melt state behaviour of PEEK and processing window interpretation for fast compression moulding process

    SciTech Connect

    Bessard, Emeline; De Almeida, Olivier; Bernhart, Gerard

    2011-01-17

    Fast mould heating is nowadays possible by using induction technology for example with the Cage System registered developed by RocTool. It allows heating and cooling kinetics of about 100 deg. C per minute and new perspectives are thus possible to optimize the compression moulding process of long fibre reinforced thermoplastic composites. Indeed, a high forming temperature may favour polymer creep and so on composite consolidation. Nevertheless, the processing time of PEEK composite above melt temperature must be reduced to a few minutes due to the fast thermal degradation of the matrix. On the other hand, high cooling rates may have negative effect on matrix crystallinity. The proposed procedure consist in performing a few minutes isotherm around 300 deg. C during the fast cooling. It would favour a high degree of crystallinity of PEEK without extending the cycle time.

  6. Melt state behaviour of PEEK and processing window interpretation for fast compression moulding process

    NASA Astrophysics Data System (ADS)

    Bessard, Emeline; De Almeida, Olivier; Bernhart, Gérard

    2011-01-01

    Fast mould heating is nowadays possible by using induction technology for example with the Cage System® developed by RocTool. It allows heating and cooling kinetics of about 100° C per minute and new perspectives are thus possible to optimize the compression moulding process of long fibre reinforced thermoplastic composites. Indeed, a high forming temperature may favour polymer creep and so on composite consolidation. Nevertheless, the processing time of PEEK composite above melt temperature must be reduced to a few minutes due to the fast thermal degradation of the matrix. On the other hand, high cooling rates may have negative effect on matrix crystallinity. The proposed procedure consist in performing a few minutes isotherm around 300° C during the fast cooling. It would favour a high degree of crystallinity of PEEK without extending the cycle time.

  7. Covalent attachment of polymeric monolith to polyether ether ketone (PEEK) tubing.

    PubMed

    Lv, Chunguang; Heiter, Jaana; Haljasorg, Tõiv; Leito, Ivo

    2016-08-17

    A new method of reproducible preparation of vinylic polymeric monolithic columns with a key step of covalently anchoring the monolith to PEEK surface is described. In order to chemically attach the polymer monolith to the tube wall, methacrylate functional groups were introduced onto PEEK surface by a three-step procedure, including surface etching, surface reduction and surface methacryloylation. The chemical state of the modified tubing surface was characterized by attenuated total reflectance infrared (ATR-IR) spectroscopy. It was found that the etching step is the key to successfully modifying the PEEK tubing surface. Poly(styrene-co-divinylbenzene) monoliths were in situ synthesized by thermally initiated free radical copolymerization within the confines of surface-vinylized PEEK tubings of dimensions close to ones conventionally used in HPLC and UHPLC (1.6 mm internal diameter, 10.0-12.5 cm length). Adhesion test was done by measuring the operating pressure drop, which the prepared stationary phases can withstand. Good pressure resistance, up to 140 bar/10 cm (flow rate 0.5 mL min(-1), acetonitrile as a mobile phase), indicates strong bonding of monolith to the tubing wall. The monolithic material was proven to have a permeability of 1.7 × 10 (-14) m(2), applying acetonitrile-water 70:30 (v/v) as a mobile phase. The column performance was reproducible from column to column and was evaluated via the isocratic separation of a series of alkylbenzenes in the reversed-phase mode (acetonitrile-water 70:30, v/v). The numbers of plates per meter at optimal flow rate were found to be between 26 000 and 32 000 for the different analytes.

  8. Proximal humeral fracture fixation: multicenter study with carbon fiber peek plate.

    PubMed

    Rotini, R; Cavaciocchi, M; Fabbri, D; Bettelli, G; Catani, F; Campochiaro, G; Fontana, M; Colozza, A; De Biase, C F; Ziveri, G; Zapparoli, C; Stacca, F; Lupo, R; Rapisarda, S; Guerra, E

    2015-09-01

    Locking plate fixation is a reliable treatment for many displaced proximal humeral fractures. Carbon fiber-reinforced-poly-ether-ether-ketone (CFR-PEEK) plates have recently been introduced as an alternative to traditional metallic plates. In a multicenter study involving the Orthopedic Services of 6 Italian hospitals, 182 patients with a proximal humeral fracture were treated with a Diphos H (Lima Corporate, San Daniele del Friuli, Italy) CFR-PEEK plate, 160 of whom were followed clinically and radiographically for 2 years or more. Fractures were classified by Neer's system. The functional results were assessed by Constant and DASH scores. The average time to radiographic healing was 5.6 months in 158 of 160 cases. Mean Constant score was 76, and mean DASH score was 28 at 2 years. There were two nonunions (one septic and one aseptic) and 13 cases of partial (9) or massive (4) humeral head necrosis. In three of the 78 patients treated with the first-generation plates, hardware breakage happened during the operation and the plate was replaced. There was no failure among the cases treated with the thicker second-generation plate. In eight cases, there was a perforation of the humeral head by the cephalic screws. CFR-PEEK plates proved as reliable as metallic plates in the treatment of proximal humeral fractures. The advantages of these new devices include a better visualization of fracture reduction during intraoperative fluoroscopic assessment and easy hardware removal due to the absence of screw-plate cold fusion.

  9. Cranioplasty with customized titanium and PEEK implants in a mechanical stress model.

    PubMed

    Lethaus, Bernd; Safi, Yara; ter Laak-Poort, Mariel; Kloss-Brandstätter, Anita; Banki, Frans; Robbenmenke, Christian; Steinseifer, Ulrich; Kessler, Peter

    2012-04-10

    Large skull defects as a result of craniectomies due to cerebral insults, trauma, or tumors create functional and aesthetic disturbances for the patient. Cranioplasty with implants in these cases are an alternative to autogenous bone transplantation. In our clinic, customized titanium or optima poly-ether-ether ketone (PEEK) implants are used to reconstruct craniectomy defects. To compare the two materials we investigated the structural changes of the implants fixed to a sintered polyamide skull model under mechanical stress in four simplified models. In a standard testing machine, the models were subjected to a load under a quasi-static loading rate of 1.925 mm/min. Fractures of the PEEK implants occurred at a force of 24.2 and 24.5 kN with a displacement of 8.4 and 8 mm. The titanium implants showed no deformation, but extensive damage was seen in the polyamide skull models. The highest pressures achieved were 45.8 and 50.9 kN. In a simplified model with quasi-static loading, both implants withstood forces that were higher than those capable of causing skull fractures. It seems that the mechanical properties of PEEK could provide better protection when used for cranioplasty in patients after craniectomy if reconstruction with autogenous bone is not possible.

  10. SAXS and NMR analysis for the cast solvent effect on sPEEK membrane properties.

    PubMed

    Luu, Dinh Xuan; Cho, Eun-Bum; Han, Oc Hee; Kim, Dukjoon

    2009-07-30

    The cast solvent effect on the structure and properties of sulfonated poly(ether ether ketone) (sPEEK) was studied. PEEK was sulfonated to have different sulfonation degrees of 65, 70, and 75%, and its membrane was prepared using the two types of solvents, N,N-dimethylacetamide (DMA) and 1-methyl-2-pyrrolidinone (NMP). Ionic cluster size was analyzed using small-angle X-ray scattering (SAXS), and it was correlated with a few essential membrane properties such as water uptake, methanol permeability, proton conductivity, and cell performance in direct methanol fuel cells (DMFCs). Synchrotron SAXS and solid state NMR data revealed the structural difference between the sPEEK membranes prepared using NMP and DMA, regarding the cluster dimensions of 3.22 and 2.70 nm, respectively. Although the water uptake, methanol permeability, and proton conductivity of the membranes prepared with NMP were higher than those with DMA, the overall cell performance was vice versa. The dimensional instability associated with high water swelling as well as high methanol permeability were the main causes for this inferior cell efficiency of NMP cast membranes. This report demonstrates the importance of selection of cast solvent in preparation of SPEEK electrolyte membranes for DMFC application.

  11. Automated Fiber Placement of PEEK/IM7 Composites with Film Interleaf Layers

    NASA Technical Reports Server (NTRS)

    Hulcher, A. Bruce; Banks, William I., III; Pipes, R. Byron; Tiwari, Surendra N.; Cano, Roberto J.; Johnston, Norman J.; Clinton, R. G., Jr. (Technical Monitor)

    2001-01-01

    The incorporation of thin discrete layers of resin between plies (interleafing) has been shown to improve fatigue and impact properties of structural composite materials. Furthermore, interleafing could be used to increase the barrier properties of composites used as structural materials for cryogenic propellant storage. In this work, robotic heated-head tape placement of PEEK/IM7 composites containing a PEEK polymer film interleaf was investigated. These experiments were carried out at the NASA Langley Research Center automated fiber placement facility. Using the robotic equipment, an optimal fabrication process was developed for the composite without the interleaf. Preliminary interleaf processing trials indicated that a two-stage process was necessary; the film had to be tacked to the partially-placed laminate then fully melted in a separate operation. Screening experiments determined the relative influence of the various robotic process variables on the peel strength of the film-composite interface. Optimization studies were performed in which peel specimens were fabricated at various compaction loads and roller temperatures at each of three film melt processing rates. The resulting data were fitted with quadratic response surfaces. Additional specimens were fabricated at placement parameters predicted by the response surface models to yield high peel strength in an attempt to gage the accuracy of the predicted response and assess the repeatability of the process. The overall results indicate that quality PEEK/lM7 laminates having film interleaves can be successfully and repeatability fabricated by heated head automated fiber placement.

  12. Get Tested for Cervical Cancer

    MedlinePlus

    ... Print This Topic En español Get Tested for Cervical Cancer Browse Sections The Basics Overview Cervical Cancer ... Cervical Cancer 1 of 5 sections The Basics: Cervical Cancer What is cervical cancer? Cervical cancer is ...

  13. Process control and interface optimisation of carbon fibre/PEEK matrix composites

    NASA Astrophysics Data System (ADS)

    Gao, Shanglin

    1999-11-01

    An investigation was made to determine the effect of cooling rate on the interphase adhesion and mechanical properties of carbon fiber/PEEK matrix composites. The fiber/matrix interface adhesion was characterized based on the fiber fragmentation and fiber pull-out tests. A series of tensile, flexure, short-beam shear, interlaminar fracture and impact tests were conducted. The interface adhesion was correlated to the degree of crystallinity and crystalline morphology, as well as the bulk mechanical properties of laminates composites. It is shown that the amorphous PEEK rich interphase introduced in fast cooled specimens results in a relatively ductile interface failure and low interfacial shear strength (IFSS), whereas the transcrystalline interphase in slow cooled specimens gives rise to a high IFSS with relatively brittle interface debonding. The sensitivity of matrix crystallinity on cooling rate was much higher than the changes in IFSS. The interlaminar shear strength (ILSS) varied with cooling rate in a manner similar to IFSS. The increases in the interlaminar, tensile and flexural properties with decreasing cooling rate was attributed to the changes in interfacial shear strength, matrix properties, and transition of the failure mechanisms which was observed from adhesive to cohesive failure when the cooling rate was decreased. The presence of brittle crystalline interphase and matrix material resulting from a low cooling rate reduced the mode I and mode II interlaminar fracture resistance despite the large contribution from the strong interface adhesion. At high cooling rates, however, the high ductility of PEEK matrix with less crystallinity was not fully translated to interlaminar fracture toughness due to the weak interfacial bond. A strong fiber/matrix interface bond is essential to the occurrence of extensive matrix plastic deformation, otherwise the matrix deformation is preempted by interfacial debonding. The fast cooled carbon/PEEK composites had

  14. Cervical insufficiency and cervical cerclage.

    PubMed

    Brown, Richard; Gagnon, Robert; Delisle, Marie-France

    2013-12-01

    The purpose of this guideline is to provide a framework that clinicians can use to determine which women are at greatest risk of having cervical insufficiency and in which set of circumstances a cerclage is of potential value. Published literature was retrieved through searches of PubMed or MEDLINE, CINAHL, and The Cochrane Library in 2012 using appropriate controlled vocabulary (e.g., uterine cervical incompetence) and key words (e.g., cervical insufficiency, cerclage, Shirodkar, cerclage, MacDonald, cerclage, abdominal, cervical length, mid-trimester pregnancy loss). Results were restricted to systematic reviews, randomized control trials/controlled clinical trials, and observational studies. There were no date or language restrictions. Searches were updated on a regular basis and incorporated in the guideline to January 2011. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. The quality of evidence in this document was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table). Recommendations 1. Women who are pregnant or planning pregnancy should be evaluated for risk factors for cervical insufficiency. A thorough medical history at initial evaluation may alert clinicians to risk factors in a first or index pregnancy. (III-B) 2. Detailed evaluation of risk factors should be undertaken in women following a mid-trimester pregnancy loss or early premature delivery, or in cases where such complications have occurred in a preceding pregnancy. (III-B) 3. In women with a history of cervical insufficiency, urinalysis for culture and sensitivity and vaginal cultures for bacterial vaginosis should be taken at the first obstetric visit and any infections so found should be treated. (I-A) 4. Women

  15. Biomechanical evaluation and surface characterization of a nano-modified surface on PEEK implants: a study in the rabbit tibia

    PubMed Central

    Johansson, Pär; Jimbo, Ryo; Kjellin, Per; Currie, Fredrik; Chrcanovic, Bruno Ramos; Wennerberg, Ann

    2014-01-01

    Polyether ether ketone (PEEK) is today frequently used as a biomaterial in different medical operations due to its excellent mechanical and chemical properties. However, the untreated surface of PEEK is bioinert and hydrophobic, and it does not osseointegrate in its pure form. The aim of this study was to evaluate a unique nano-modified surface of PEEK with respect to osseointegration. Forty-eight threaded, non-cutting PEEK implants were inserted bilaterally in the tibia of 24 rabbits. Half of the implants (n=24) were coated with nanocrystalline hydroxyapatite (test) and the remaining implants (n=24) were left uncoated (control). Half of the animals (n=12) were euthanized after 3 weeks of healing and the remaining (n=12) after 12 weeks. The implant retention was measured with a removal torque apparatus. Surface analysis was performed with interferometry, scanning electron microscopy, and X-ray photon spectroscopy to relate the removal torque to the applied surface. The test implants revealed a significantly higher retention after 3 weeks (P=0.05) and 12 weeks (P=0.028) compared to controls. The result of the present study proves that the addition of nanocrystalline hydroxyapatite coating to PEEK surfaces significantly increases its removal torque and biocompatibility. PMID:25152620

  16. Rate-dependent mode I interlaminar crack growth mechanisms in graphite/epoxy and graphite/PEEK

    NASA Technical Reports Server (NTRS)

    Gillespie, J. W., Jr.; Carlsson, L. A.; Smiley, A. J.

    1987-01-01

    In this paper the mode I fracture behavior of graphite/epoxy and graphite/PEEK composites is examined over four decades of crosshead rates (0.25-250 mm/min). Straight-sided double-cantilever-beam specimens consisting of unidirectional laminates were tested at room temperature. For graphite/epoxy the load-deflection response was linear to fracture, and stable slow crack growth initiating at the highest load level was observed for all rates tested. In contrast, mode I crack growth in the graphite/PEEK material was often unstable and showed stick-slip behavior. Subcritical crack growth occurring prior to the onset of fracture was observed at intermediate displacement rates. A mechanism for the fracture behavior of the graphite/PEEK material (based on viscoelastic, plastic, and microcrack coalescence in the process zone) is proposed and related to the observed rate-dependent phenomena.

  17. Glycine: A potential coupling agent to bond to helium plasma treated PEEK?

    PubMed

    Schmidlin, Patrick R; Eichberger, Marlis; Stawarczyk, Bogna

    2016-02-01

    To test the tensile bond strength (TBS) between two self-adhesive resin composite cements and PEEK after helium plasma treatment and used glycine as a potential coupling agent incorporated in different adhesives. In summary, 896 air-abraded PEEK specimens were fabricated. Half of the specimens were treated with cold active inert helium plasma and the other half were left non-treated. Both groups were then split in two groups: In group 1 (n=256), 64 specimens were pre-treated with: (a) soft-liner liquid, (b) visio.link, (c) Ambarino P60 and (d) no pre-treatment (control), respectively. In group 2 (n=192), specimens were conditioned accordingly, but the adhesive materials were modified by including a commercially available glycine (Air-Flow PERIO). PEEK specimens were then luted using either RelyX Unicem or Clearfil SA Cement and TBS was measured initially and after 14 days water storage combined with 10'000 thermal cycles (16 specimens/subgroup). Fracture type analysis was performed. For statistical analyses Kolmogorov-Smirnov, Shapiro-Wilk tests, 1-, 4-way ANOVA (post hoc: Scheffé), and t-test were used (p<0.001). Helium plasma pre-treatment without glycine showed no impact on initial TBS (p>0.348). In contrast, a combination between glycine application and Softline/Ambarino P60 allowed for significantly higher initial TBS was measured after helium plasma treatment (p=0.001). However, this effect was no evident after thermo-cycling. All groups conditioned with visio.link showed the highest TBS values. The introduction of amine groups by simple provision of amino acids in the form of glycine can improve the bond strength after helium plasma treatment using different adhesive materials. However, using this simple approach, the method cannot withstand thermal challenge yet. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Elastic-plastic analysis of AS4/PEEK composite laminate using a one-parameter plasticity model

    NASA Technical Reports Server (NTRS)

    Sun, C. T.; Yoon, K. J.

    1992-01-01

    A one-parameter plasticity model was shown to adequately describe the plastic deformation of AS4/PEEK (APC-2) unidirectional thermoplastic composite. This model was verified further for unidirectional and laminated composite panels with and without a hole. The elastic-plastic stress-strain relations of coupon specimens were measured and compared with those predicted by the finite element analysis using the one-parameter plasticity model. The results show that the one-parameter plasticity model is suitable for the analysis of elastic-plastic deformation of AS4/PEEK composite laminates.

  19. SILICOMB PEEK Kirigami cellular structures: mechanical response and energy dissipation through zero and negative stiffness

    NASA Astrophysics Data System (ADS)

    Virk, K.; Monti, A.; Trehard, T.; Marsh, M.; Hazra, K.; Boba, K.; Remillat, C. D. L.; Scarpa, F.; Farrow, I. R.

    2013-08-01

    The work describes the manufacturing, testing and parametric analysis of cellular structures exhibiting zero Poisson’s ratio-type behaviour, together with zero and negative stiffness effects. The cellular structures are produced in flat panels and curved configurations, using a combination of rapid prototyping techniques and Kirigami (Origami and cutting) procedures for PEEK (Polyether Ether Ketone) thermoplastic composites. The curved cellular configurations show remarkable large deformation behaviours, with zero and negative stiffness regimes depending also on the strain rate applied. These unusual stiffness characteristics lead to a large increase of energy absorption during cyclic tests.

  20. MoS2-Filled PEEK Composite as a Self-Lubricating Material for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Theiler, Geraldine; Gradt, Thomas

    2010-01-01

    At BAM, several projects were conducted in the past years dealing with the tribological properties of friction couples at cryogenic temperature and in vacuum environment. Promising candidates for vacuum application are MoS2-filled PEEK/PTFE composites, which showed a friction coefficient as low as 0.03 in high vacuum. To complete the tribological profile of these composites, further tests were performed in ultra-high vacuum (UHV) at room temperature. In this paper, friction and stick slip behavior, as well as outgassing characteristics during the test are presented.

  1. Clinical Validation of Smartphone Based Adapter: Peek Retina for Optic Disc Imaging in Kenya

    PubMed Central

    Bastawrous, Andrew; Giardini, Mario Ettore; Bolster, Nigel M; Peto, Tunde; Shah, Nisha; Livingstone, Iain AT; Weiss, Helen A.; Hu, Sen; Rono, Hillary; Kuper, Hannah; Burton, Matthew

    2017-01-01

    Importance Visualization and interpretation of the optic nerve and retina is an essential part of most physical examinations. Objectives To design and validate a smartphone-based retinal adapter enabling image capture and remote grading of the retina Design, setting and participants Validation study comparing the grading of optic nerves from smartphones images with those of a Digital Fundus Camera. Both image sets were independently graded at Moorfields Eye Hospital Reading Centre. Nested within the six-year follow-up of the Nakuru Eye Disease Cohort in Kenya: 1,460adults (2,920eyes) aged 55years and above were recruited consecutively from the Study. A sub-set of 100 optic disc images from both methods were further used to validate a grading app for the optic nerves. Main outcome(s) and measure(s) Vertical cup-to-disc-ratio (VCDR) for each test was compared, in terms of agreement (Bland-Altman & weighted Kappa) and test-retest variability (TRV). Results 2,152 optic nerve images were available from both methods (additionally 371 from reference but not Peek, 170 from Peek but not the reference and 227 from neither the reference camera or Peek). Bland-Altman analysis demonstrated a difference of the average of 0.02 with 95% limits of agreement between -0.21 and 0.17 and a weighted Kappa coefficient of 0.69 (excellent agreement). An experienced retinal photographer was compared to a lay photographer (no health care experience prior to the study) with no observable difference in image acquisition quality between them. Conclusions and relevance Non-clinical photographers using the low-cost Peek Retina adapter and smartphone were able to acquire optic nerve images at a standard that enabled comparable independent remote grading of the images to those acquired using a desktop retinal camera operated by an ophthalmic assistant. The potential for task-shifting and the detection of avoidable causes of blindness in the most at risk communities makes this an attractive public

  2. Dissipation of mechanical work and temperature rise in AS4/PEEK thermoplastic composite

    NASA Technical Reports Server (NTRS)

    Georgiou, I.; Sun, C. T.

    1990-01-01

    The dissipated mechanical work per cycle of sinusoidal stress in the thermoplastic composite material AS4/PEEK was measured as a function of stress amplitude for fixed frequency and fiber orientation. The experimental result shows that the dissipated work per cycle is proportional to the square of the stress amplitude. Using the concept of the equivalent isotropic material, it is shown that the relaxation modulus satisfies a proportionality condition. Also, the rate of temperature rise due to sinusoidal stresses has been measured as a function of stress amplitude. The result shows that the rate of temperature rise is not proportional to the square of the stress amplitude.

  3. Accelerated simulations of aromatic polymers: application to polyether ether ketone (PEEK)

    NASA Astrophysics Data System (ADS)

    Broadbent, Richard J.; Spencer, James S.; Mostofi, Arash A.; Sutton, Adrian P.

    2014-10-01

    For aromatic polymers, the out-of-plane oscillations of aromatic groups limit the maximum accessible time step in a molecular dynamics simulation. We present a systematic approach to removing such high-frequency oscillations from planar groups along aromatic polymer backbones, while preserving the dynamical properties of the system. We consider, as an example, the industrially important polymer, polyether ether ketone (PEEK), and show that this coarse graining technique maintains excellent agreement with the fully flexible all-atom and all-atom rigid bond models whilst allowing the time step to increase fivefold to 5 fs.

  4. Characterization of elastic-viscoplastic properties of an AS4/PEEK thermoplastic composite

    NASA Technical Reports Server (NTRS)

    Yoon, K. J.; Sun, C. T.

    1991-01-01

    The elastic-viscoplastic properties of an AS4/PEEK (APC-2) thermoplastic composite were characterized at 24 C (75 F) and 121 C (250 F) by using a one-parameter viscoplasticity model. To determine the strain-rate effects, uniaxial tension tests were performed on unidirectional off-axis coupon specimens with different monotonic strain rates. A modified Bodner and Partom's model was also used to describe the viscoplasticity of the thermoplastic composite. The experimental results showed that viscoplastic behavior can be characterized quite well using the one-parameter overstress viscoplasticity model.

  5. Bonding of composite resins to PEEK: the influence of adhesive systems and air-abrasion parameters.

    PubMed

    Stawarczyk, Bogna; Taufall, Simon; Roos, Malgorzata; Schmidlin, Patrick R; Lümkemann, Nina

    2017-06-24

    The objective of the study was to investigate the tensile bond strength (TBS) to polyaryletheretherketone (PEEK) after different pretreatment and conditioning methods. Four hundred PEEK specimens were fabricated and allocated to the following air-abrasion methods (n 1 = 80/pretreatment): (i) 50 μm Al2O3 (0.05 MPa); (ii) 50 μm Al2O3 (0.35 MPa); (iii) 110 μm Al2O3 (0.05 MPa); (iv) 110 μm Al2O3 (0.35 MPa); and (v) Rocatec 110 μm (0.28 MPa). These pretreatments were combined with the following conditioning methods (n 2 = 20/pretreatment/conditioning): (a) visio.link (VL); (b) Monobond Plus/Heliobond (MH); (c) Scotchbond Universal (SU); and (d) dialog bonding fluid (DB). After veneering of all specimens with dialog occlusal and aging (28 days H2O, 37 °C + 20,000 thermal cycles, 5/55 °C), TBS was measured. Data was analysed using Kaplan-Meier survival analysis with Breslow-Gehan test and Cox-regressions. The major impact on TBS showed the conditioning, followed by the air-abrasion-pressure, while the grain size of the air-abrasion powder did not show any effect. Specimens air-abraded at 0.35 MPa showed the highest survival rates. However, within VL groups, this observation was not statistically significant. Within MH groups, pretreatment using 110 μm Al2O3 and 0.05 MPa resulted in higher survival rates compared to groups treated with 50 and 110 μm Al2O3 using a pressure of 0.35 MPa. The use of VL showed the highest survival rates between the adhesive systems and the TBS values higher than 25 MPa independent of the pretreatment method. As an exception, only VL showed significantly higher survival rates when compared to MH. The adequate choice of the adhesive system and higher pressures improved the TBS between PEEK and veneering resin composite. The particle size had no major impact. According to this study, best veneering of PEEK with dialog occlusal can be achieved by conditioning with visio.link in combination with the pretreatment of

  6. Cervical Cancer Screening

    MedlinePlus

    ... cervical cancer screening? • If I have had a hysterectomy, do I still need cervical cancer screening? • Are ... past 5 years. If I have had a hysterectomy, do I still need cervical cancer screening? If ...

  7. Cervical Cancer Stage IIIA

    MedlinePlus

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIA Add to My Pictures View / ... 1275x1275 View Download Large: 2550x2550 View Download Title: Cervical Cancer Stage IIIA Description: Stage IIIA cervical cancer; ...

  8. Cervical Cancer Stage IIIB

    MedlinePlus

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIB Add to My Pictures View / ... 1425x1326 View Download Large: 2850x2651 View Download Title: Cervical Cancer Stage IIIB Description: Stage IIIB cervical cancer; ...

  9. Cervical Cancer Stage IVB

    MedlinePlus

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IVB Add to My Pictures View / ... 1200x1305 View Download Large: 2400x2610 View Download Title: Cervical Cancer Stage IVB Description: Stage IVB cervical cancer; ...

  10. Cervical Cancer Stage IVA

    MedlinePlus

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IVA Add to My Pictures View / ... 1575x1200 View Download Large: 3150x2400 View Download Title: Cervical Cancer Stage IVA Description: Stage IVA cervical cancer; ...

  11. Cervical Spondylosis and Hypertension

    PubMed Central

    Peng, Baogan; Pang, Xiaodong; Li, Duanming; Yang, Hong

    2015-01-01

    Abstract Cervical spondylosis and hypertension are all common diseases, but the relationship between them has never been studied. Patients with cervical spondylosis are often accompanied with vertigo. Anterior cervical discectomy and fusion is an effective method of treatment for cervical spondylosis with cervical vertigo that is unresponsive to conservative therapy. We report 2 patients of cervical spondylosis with concomitant cervical vertigo and hypertension who were treated successfully with anterior cervical discectomy and fusion. Stimulation of sympathetic nerve fibers in pathologically degenerative disc could produce sympathetic excitation, and induce a sympathetic reflex to cause cervical vertigo and hypertension. In addition, chronic neck pain could contribute to hypertension development through sympathetic arousal and failure of normal homeostatic pain regulatory mechanisms. Cervical spondylosis may be one of the causes of secondary hypertension. Early treatment for resolution of symptoms of cervical spondylosis may have a beneficial impact on cardiovascular disease risk in patients with cervical spondylosis. PMID:25761188

  12. Cervical cancer.

    PubMed

    Shepherd, John H

    2012-06-01

    Standard treatment for invasive cervical cancer involves either radical surgery or radiotherapy. Childbearing is therefore impossible after either of these treatments. A fertility-sparing option, however, by radical trachelectomy has been shown to be effective, provided that strict criteria for selection are followed. Fertility rates are high, whereas recurrence is low, indicating that a more conservative approach to dealing with early small cervical tumours is feasible. Careful preoperative assessment by magnetic resonance imaging scans allows accurate measurement of the tumour with precise definition to plan surgery. This will ensure an adequate clear margin by wide excision of the tumour excising the cervix by radical vaginal trachelectomy with surrounding para-cervical and upper vaginal tissues. An isthmic cerclage is inserted to provide competence at the level of the internal orifice. A primary vagino-isthmic anastomosis is conducted to restore continuity of the lower genital tract. Subsequent pregnancies require careful monitoring in view of the high risk of spontaneous premature rupture of the membranes. Delivery by classical caesarean section is necessary at the onset of labour or electively before term. Over 1100 such procedures have been carried out vaginally or abdominally, resulting in 240 live births. Radical vaginal trachelectomy with a laparoscopic pelvic-node dissection offers the least morbid and invasive route for surgery, provided that adequate surgical skills have been obtained.

  13. Comparative in vitro wear testing of PEEK and UHMWPE capped metacarpophalangeal prostheses.

    PubMed

    Joyce, T J; Rieker, C; Unsworth, A

    2006-01-01

    Six metacarpophalangeal prostheses were each wear tested to five million cycles. Each prosthesis consisted of a metacarpal component with an approximately hemispherical shell on a titanium body, articulating against a titanium phalangeal component. Four prostheses had a shell made from ultra-high molecular weight polyethylene (UHMWPE) and two had a shell made from polyether ether ketone (PEEK). The tests were undertaken using a finger wear simulator. Despite pre-soaking and the use of control components, lubricant uptake by the metacarpal components was significant. Gravimetrically, the UHMWPE test components showed a greater weight gain than the UHMWPE control components. Therefore there was no apparent wear of any of the UHMWPE test metacarpal components. The original concentric machining marks of the UHMWPE components could still be seen after five million cycles of testing. For the metacarpal components with PEEK shells, gravimetric wear could be measured. Gravimetrically, all of the titanium phalangeal components showed little or no wear. Light scratches in the direction of sliding appeared on the articulating faces of all metacarpal and phalangeal test components, indicating slight abrasive wear.

  14. Damage profile examination on ion irradiated PEEK by 6Li doping and neutron depth profiling technique

    NASA Astrophysics Data System (ADS)

    Vacík, J.; Červená, J.; Hnatowicz, V.; Švorčík, V.; Kobayashi, Y.; Fink, D.; Klett, R.

    1998-05-01

    Depth structure of radiation damaged surface layer of poly(aryl-ether-ether ketone) (PEEK) a polymer was studied using doping with 6Li atoms combined with nondestructive neutron depth profiling (NDP) method. The PEEK foils were irradiated with 2 MeV O + ions up to a fluence of 6 × 10 14 ions/cm 2. The damage profiles in the samples were visualized by doping of the samples with 5 M LiCl water solution at room temperature (RT) for 22.5 h. The Li ions are trapped on ion-produced radiation defects and the Li depth profiles are determined by the NDP method. NDP experiments were performed before and after leaching of excess of lithium atoms from the samples in distilled water at RT for 2 h. The leaching leads to dramatic changes in the Li depth distribution which, at low ion fluences, is similar in shape to the electronic energy loss profile of 2 MeV O + ions. For the higher fluences double-peaked profile occurs, which indicates a competition between different degradation processes in ion irradiated polymer.

  15. Feasibility of knitted carbon/PEEK composites for orthopedic bone plates.

    PubMed

    Fujihara, K; Huang, Zheng-Ming; Ramakrishna, S; Satknanantham, K; Hamada, H

    2004-08-01

    This paper focuses on fabrication and characterization of knitted carbon/PEEK fabric composites for orthopedic bone plate application. Bending performance of the knitted carbon/PEEK composite bone plates was investigated with respect to two principal knitting directions (wale- and course-directions). As a result, the wale-direction knitted composite bone plates had much scattering in bending stiffness and maximum bending moment although they exhibited the same bending behavior as that of the course-direction specimens. In comparison with our previously developed braided composite bone plates, the knitted composite bone plates had 55-59% bending stiffness, 40-63% yield bending moment, and 54-77% maximum bending moment. However, the knitted composite bone plates showed higher deformability. Based on the results of the braided composite bone plates, it is considered that the knitted composite plate with 3.2mm thickness can be suitable for forearm or humerus treatment especially when damaged bones need higher deformation to encourage bone ossification.

  16. Radiological survey results for the Peek Street site properties, Schenectady, New York

    SciTech Connect

    Foley, R.D.; Cottrell, W.D.; Carrier, R.F.

    1992-08-01

    The Peek Street Industrial Facility, located at 425 Peek Street, Schenectady, New York, was operated by the General Electric Company for the Atomic Energy Commission (AEC) between 1947 and 1955. A variety of operations using radioactive materials were conducted at the site, but the main activities were to design an intermediate breeder reactor and to develop a chemical process for the recovery of uranium and plutonium from spent reactor fuel. Nonradioactive beryllium metal was machined on the site for breeder reactor application. The 4.5-acre site was decommissioned and released in October 1955. A radiological survey was conducted by Oak Ridge National Laboratory in November 1989. The survey included scan and grid point measurements of direct radiation levels outdoors on the five properties and inside the factory building, and radionuclide analysis of samples collected from each property. Radionuclide concentrations were determined in outdoor surface and subsurface soil samples from each property and in dust, debris, and structural materials from inside the factory building. Auger holes were logged to assess location and extent of possible subsurface residual soil radioactivity. Radionuclide concentrations were deter-mined in both indoor and outdoor water samples and in selected samples of vegetation. The presence of fixed and transferable surface residual radioactivity was investigated inside the factory building and on discarded materials outdoors on the property. High-volume air samples as well as additional selected indoor and outdoor soil samples were analyzed to determine levels of elemental beryllium.

  17. Laminoplasty for Cervical Myelopathy

    PubMed Central

    Ito, Manabu; Nagahama, Ken

    2012-01-01

    This article reviews cervical laminoplasty. The origin of cervical laminoplasty dates back to cervical laminectomy performed in Japan ~50 years ago. To overcome poor surgical outcomes of cervical laminectomy, many Japanese orthopedic spine surgeons devoted their lives to developing better posterior decompression procedures for the cervical spine. Thanks to the development of a high-speed surgical burr, posterior decompression procedures for the cervical spine showed vast improvement from the 1970s to the 1980s, and the original form of cervical laminoplasty was determined. Since around 2000, surgeons performing cervical laminoplasty have been adopting less invasive procedures for the posterior cervical muscle structures so as to minimize postoperative axial neck pain and obtain better functional outcomes of the cervical spine. This article covers the history of cervical laminoplasty, surgical procedures, the benefits and limitation of this procedure, and surgery-related complications. PMID:24353967

  18. Cervical Laminoplasty for Multilevel Cervical Myelopathy

    PubMed Central

    Sayana, Murali Krishna; Jamil, Hassan; Poynton, Ashley

    2011-01-01

    Cervical spondylotic myelopathy can result from degenerative cervical spondylosis, herniated disk material, osteophytes, redundant ligamentum flavum, or ossification of the posterior longitudinal ligament. Surgical intervention for multi-level myelopathy aims to decompress the spinal cord and maintain stability of the cervical spine. Laminoplasty was major surgical advancement as laminectomy resulted in kyphosis and unsatisfactory outcomes. Hirabayashi popularised the expansive open door laminoplasty which was later modified several surgeons. Laminoplasty has changed the way surgeons approach multilevel cervical spondylotic myelopathy. PMID:21991408

  19. Prediction and Control of Processing-Induced Residual Stresses in Composites. Part 2. AS4/PEEK Composite

    DTIC Science & Technology

    1989-10-01

    model was used to predict dimensionless curvatures. The model underestimates the residual stresses at high temperatures near the onset of crystallization...Crystallization (Thermal-Elastic Model ) ................... 63 Figure 46 Tensile Creep Compliance Master Curve for 33% Crystalline Neat PEEK for Testing...Curvature by Viscoelastic Analysis (VE Model ) as a Function of Cool Down Temperature .......................................... 68 V LIST OF TABLES Page

  20. On the thermally-induced residual stresses in thick fiber-thermoplastic matrix (PEEK) cross-ply laminated plates

    NASA Technical Reports Server (NTRS)

    Hu, Shoufeng; Nairn, John A.

    1992-01-01

    An analytical method for calculating thermally-induced residual stresses in laminated plates is applied to cross-ply PEEK laminates. We considered three cooling procedures: slow cooling (uniform temperature distribution); convective and radiative cooling; and rapid cooling by quenching (constant surface temperature). Some of the calculated stresses are of sufficient magnitude to effect failure properties such as matrix microcracking.

  1. Selective responses of human gingival fibroblasts and bacteria on carbon fiber reinforced polyetheretherketone with multilevel nanostructured TiO2.

    PubMed

    Wang, Xiao; Lu, Tao; Wen, Jin; Xu, Lianyi; Zeng, Deliang; Wu, Qianju; Cao, Lingyan; Lin, Shuxian; Liu, Xuanyong; Jiang, Xinquan

    2016-03-01

    The long-term success of dental implants relies not only on stable osseointegration but also on the integration of implant surfaces with surrounding soft tissues. In our previous work, titanium plasma immersion ion implantation (PIII) technique was applied to modify the carbon-fiber-reinforced polyetheretherketone (CFRPEEK) surface, constructing a unique multilevel TiO2 nanostructure thus enhancing certain osteogenic properties. However, the interactions between the modified surface and soft-tissue cells are still not clear. Here, we fully investigate the biological behaviors of human gingival fibroblasts (HGFs) and oral pathogens on the structured surface, which determine the early peri-implant soft tissue integration. Scanning electron microscopy (SEM) shows the formation of nanopores with TiO2 nanoparticles embedded on both the sidewall and bottom. In vitro studies including cell adhesion, viability assay, wound healing assay, real-time PCR, western blot and enzyme-linked immunosorbent assay (ELISA) disclose improved adhesion, migration, proliferation, and collagen secretion ability of HGFs on the modified CFRPEEK. Moreover, the structured surface exhibits sustainable antibacterial properties towards Streptococcus mutans, Fusobacterium nucleatum and Porphyromonas gingivalis. Our results reveal that the multilevel TiO2 nanostructures can selectively enhance soft tissue integration and inhibit bacterial reproduction, which will further support and broaden the adoption of CFRPEEK materials in dental fields.

  2. PEEK-OPTIMA™ as an alternative to cobalt chrome in the femoral component of total knee replacement: A preliminary study

    PubMed Central

    Cowie, Raelene M; Briscoe, Adam; Fisher, John; Jennings, Louise M

    2016-01-01

    PEEK-OPTIMA™ (Invibio Ltd, UK) has been considered as an alternative joint arthroplasty bearing material due to its favourable mechanical properties and the biocompatibility of its wear debris. In this study, the potential to use injection moulded PEEK-OPTIMA™ as an alternative to cobalt chrome in the femoral component of a total knee replacement was investigated in terms of its wear performance. Experimental wear simulation of three cobalt chrome and three PEEK-OPTIMA™ femoral components articulating against all-polyethylene tibial components was carried out under two kinematic conditions: 3 million cycles under intermediate kinematics (maximum anterior-posterior displacement of 5 mm) followed by 3 million cycles under high kinematic conditions (anterior-posterior displacement 10 mm). The wear of the GUR1020 ultra-high-molecular-weight polyethylene tibial components was assessed by gravimetric analysis; for both material combinations under each kinematic condition, the mean wear rates were low, that is, below 5 mm3/million cycles. Specifically, under intermediate kinematic conditions, the wear rate of the ultra-high-molecular-weight polyethylene tibial components was 0.96 ± 2.26 mm3/million cycles and 2.44 ± 0.78 mm3/million cycle against cobalt chrome and PEEK-OPTIMA™ implants, respectively (p = 0.06); under high kinematic conditions, the wear rates were 2.23 ± 1.85 mm3/million cycles and 4.44 ± 2.35 mm3/million cycles, respectively (p = 0.03). Following wear simulation, scratches were apparent on the surface of the PEEK-OPTIMA™ femoral components. The surface topography of the femoral components was assessed using contacting profilometry and showed a statistically significant increase in measured surface roughness of the PEEK-OPTIMA™ femoral components compared to the cobalt chrome implants. However, this did not appear to influence the wear rate, which remained linear over the duration of the study. These

  3. Effects of Material Combinations on Friction and Wear of PEEK/Steel Pairs under Oil-Lubricated Sliding Contacts

    NASA Astrophysics Data System (ADS)

    Akagaki, T.; Nakamura, T.; Hashimoto, Y.; Kawabata, M.

    2017-05-01

    The effects of material combinations on the friction and wear of PEEK/steel pairs are studied using blocks on a ring wear tester under oil-lubricated conditions. The rings are made of forged steel (SF540A) and a PEEK composite filled with 30 wt% carbon fibre. The surface roughness is 0.15 and 0.32 μm Ra, respectively. The blocks are also made of the same materials as the rings: the forged steel and the PEEK composite. Finished with an emery paper of #600, the surface roughness is 0.06 and 0.23 μm Ra, respectively. Sliding tests for 4 combinations of two materials are conducted. The load is increased up to 1177 N at 1 N s-1. The sliding velocity is varied in the range of 10 to 19 m s-1. In some cases, the ring temperature is measured with a thermocouple with a diameter of 0.5 mm, located 1 mm below the frictional surface. Results indicate that the forged steel’s ring and the PEEK composite’s block is the best combination among 4 combinations, because seizure does not occur under the increasing load up to 1177 N at the sliding velocity of 10-19 m s-1. In contrast, seizure occurs at 15 and 19 m s-1 in the other three combinations. However, the PEEK composite’s ring shows a lower friction coefficient as compared to the forged steel’s ring, when seizure does not occur. Wear scars are observed with a scanning electron microscope (SEM). The seizure mechanisms are then discussed.

  4. Master plot analysis of microcracking in graphite/epoxy and graphite/PEEK laminates

    NASA Technical Reports Server (NTRS)

    Nairn, John A.; Hu, Shoufeng; Bark, Jong Song

    1993-01-01

    We used a variational stress analysis and an energy release rate failure criterion to construct a master plot analysis of matrix microcracking. In the master plot, the results for all laminates of a single material are predicted to fall on a single line whose slope gives the microcracking toughness of the material. Experimental results from 18 different layups of AS4/3501-6 laminates show that the master plot analysis can explain all observations. In particular, it can explain the differences between microcracking of central 90 deg plies and of free-surface 90 deg plies. Experimental results from two different AS4/PEEK laminates tested at different temperatures can be explained by a modified master plot that accounts for changes in the residual thermal stresses. Finally, we constructed similar master plot analyses for previous literature microcracking models. All microcracking theories that ignore the thickness dependence of the stresses gave poor results.

  5. A study on UV laser drilling of PEEK reinforced with carbon fibers

    NASA Astrophysics Data System (ADS)

    Romoli, L.; Fischer, F.; Kling, R.

    2012-03-01

    This paper deals with the application of Nd-YAG laser emitting at 355 nm to the drilling process of Carbon Fiber Reinforced Polyetheretherkethone (PEEK-CF) laminates. The combination of a modern UV-laser source with a scanning technology enabling speeds up to 4 m/s, suppresses heat affected zones (HAZ) and consequently detachment of fibers from the polymer matrix. A removal technique based on the ablation of superimposed layers of composite material is proposed and analyzed in detail as a function of energy density delivered to the surface, hatch strategy and thickness of the laminate to be drilled. The hatching technique discussed in the paper is compared with conventional laser trepanning and percussion drilling through holes for the realization of 2 mm and 0.1 mm diameter, respectively. In both the cases benefits were noticed in terms of extension of HAZ and quality of the cut edges.

  6. The Development and Validation of a Smartphone Visual Acuity Test (Peek Acuity) for Clinical Practice and Community-Based Fieldwork

    PubMed Central

    Bastawrous, Andrew; Rono, Hillary; Livingstone, Iain AT; Weiss, Helen A.; Jordan, Stewart; Kuper, Hannah; Burton, Matthew

    2017-01-01

    Importance Visual acuity is the most frequently performed measure of visual function in clinical practice and the majority of people worldwide living with visual impairment are living in low and middle-income countries Objective To design and validate a smartphone-based visual acuity test that is not dependent on familiarity with symbols or letters commonly used in the English language. Design Validation study comparing results from smartphone Peek Acuity to Snellen Acuity (clinical normal) and the Early Treatment Diabetic Retinopathy Study (ETDRS) LogMAR chart (reference standard). Setting This study was nested within the six-year follow-up of the Nakuru Eye Disease Cohort in central Kenya. Participants Three hundred adults aged 55 years and above, recruited consecutively from the Nakuru Eye Disease Cohort Study.. Main Outcome(s) and Measure(s) Outcome measures were monocular logarithm of the minimum angle of resolution (LogMAR) visual acuity scores for each test: ETDRS LogMAR, Snellen and Peek. Peek was compared, in terms of test-retest variability (TRV) and measurement time, with that of the Snellen and ETDRS LogMAR chart in participants’ homes and temporary clinic settings in rural Kenya in 2013/2014. Results The 95% confidence limits for TRV of smartphone acuity data were +/-0.033 LogMAR. The mean difference between smartphone and ETDRS and smartphone and Snellen acuity data was 0.07 (95%CI: 0.05-0.09) and 0.08 (95%CI: 0.06-0.10) LogMAR respectively indicating that smartphone acuities agreed well with those of the ETDRS chart and Snellen. The agreement of Peek and ETDRS was greater than Snellen with ETDRS, p=0.08 (95%CI 0.05 to 0.10). The local Kenyan community health care workers readily accepted the Peek Acuity smartphone test; it required minimal training and took no longer than Snellen; 77s vs. 82s (95%CI: 71 – 84s vs. 73 – 91s, p=0.13). Conclusions The study demonstrated that the Peek Acuity smartphone test is capable of accurate and repeatable

  7. Novel melt-processable poly(ether ether ketone)(PEEK)/inorganic fullerene-like WS(2) nanoparticles for critical applications.

    PubMed

    Naffakh, Mohammed; Díez-Pascual, Ana M; Marco, Carlos; Gómez, Marián A; Jiménez, Ignacio

    2010-09-09

    The combination of high-performance thermoplastic poly(ether ether ketone) (PEEK) with inorganic fullerene-like tungsten disulfide (IF-WS(2)) nanoparticles offers an attractive way to combine the merits of organic and inorganic materials into novel polymer nanocomposite materials. Here, we report the processing of novel PEEK/IF-WS(2) nanocomposites, which overcome the nanoparticle agglomerate formation and provide PEEK-particle interactions. The IF-WS(2) nanoparticles do not require exfoliation or modification, making it possible to obtain stronger, lighter materials without the complexity and processing cost associated with these treatments. The nanocomposites were fabricated by melt blending, after a predispersion step based on ball milling and mechanical treatments in organic solvent, which leads to the dispersion of individually IF-WS(2) nanoparticles in the PEEK matrix as confirmed by scanning electron microscopy. In order to determine the performance of the PEEK/IF-WS(2) nanocomposites for potential critical applications, particularly for the aircraft industry, we have extensively investigated these materials with a wide range of structural, thermal, and mechanical techniques using time-resolved synchrotron X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, dynamic-mechanical analysis, and tensile and impact tests as well as thermal measurements. Modulus, tensile strengh, thermal stability, and thermal conductivity of PEEK exhibited remarkable improvement with the addition of IF-WS(2).

  8. Experimental determination of Grüneisen gamma for polyether ether ketone (PEEK) using the shock-reverberation technique

    NASA Astrophysics Data System (ADS)

    Roberts, Andrew; Appleby-Thomas, Gareth James; Hazell, Paul

    2012-03-01

    Following multiple loading events the resultant shock state of a material will lie away from the principle Hugoniot. Prediction of such states requires knowledge of a materials equation-of-state. The material-specific variable Grüneisen gamma, γ(v), defines the shape of "off-Hugoniot" points in energy-volume-pressure space. Here, the shock response of the important temperature-resistant polymer polyether ether ketone (PEEK) was compared to ANSYS Autodyn® simulations in an attempt to estimate a value of γ1. However, inconsistencies between experimental and computational results were found, highlighting the importance of full knowledge of material properties for such analyses. In particular, this approach led to revision of the established equation-of-state for PEEK, with a new nonlinear form identified.

  9. Acceptability, Usability, and Views on Deployment of Peek, a Mobile Phone mHealth Intervention for Eye Care in Kenya: Qualitative Study

    PubMed Central

    Karanja, Sarah; Lees, Shelley; Bastawrous, Andrew

    2016-01-01

    Background The Portable Eye Examination Kit (Peek) is a mobile phone–based ophthalmic testing system that has been developed to perform comprehensive eye examinations. Shortages in ophthalmic personnel, the high cost, and the difficulty in transporting equipment have made it challenging to offer services, particularly in rural areas. Peek offers a solution for overcoming barriers of limited access to traditional ophthalmic testing methods and has been pilot tested on adults in Nakuru, Kenya, and compared with traditional eye examination tools. Objective This qualitative study evaluated the acceptability and usability of Peek in addition to perceptions regarding its adoption and nationwide deployment. Methods Semistructured interviews were conducted with patients and analyzed using a framework approach. This included analysis of interviews from 20 patients, 8 health care providers (HCPs), and 4 key decision makers in ophthalmic health care provision in Kenya. The participants were purposefully sampled. The coding structure involved predefined themes for assessing the following: (1) the context, that is, environment, user, task, and technology; (2) patient acceptability, that is, patients' perceived benefits, patient preference, and patient satisfaction; (3) usability, that is, efficiency, effectiveness, learnability, and flexibility and operability of Peek; and (4) the benefits of Peek in strengthening eye care provision, that is, capabilities enhancer, opportunity creator, social enabler, and knowledge generator. Emerging themes relating to the objectives were explored from the data using thematic analysis. Results Patients found Peek to be acceptable because of its benefits in overcoming the barriers to accessing ophthalmic services. Most thought it to be fast, convenient, and able to reach a large population. All patients expressed being satisfied with Peek. The HCPs perceived it to satisfy the criteria for usability and found Peek to be acceptable based on the

  10. Carbon/PEEK composite materials as an alternative for stainless steel/titanium hip prosthesis: a finite element study.

    PubMed

    Rezaei, Farshid; Hassani, Kamran; Solhjoei, Nosratollah; Karimi, Alireza

    2015-12-01

    Total hip replacement (THR) has been ranked within the most typical surgical processes in the world. The durability of the prosthesis and loosening of prosthesis are the main concerns that mostly reported after THR surgeries. In THR, the femoral prosthesis can be fixed by either cement or cementless methods in the patient's bones. In both procedures, the stability of the prosthesis in the hosted bone has a key asset in its long-term durability and performance. This study aimed to execute a comparative finite element simulation to assess the load transfer between the prosthesis, which is made of carbon/PEEK composite and stainless steel/titanium, and the femur bone. The mechanical behavior of the cortical bone was assumed as a linear transverse isotropic while the spongy bone was modeled like a linear isotropic material. The implants were made of stainless steel (316L) and titanium alloy as they are common materials for implants. The results showed that the carbon/PEEK composites provide a flatter load transfer from the upper body to the leg compared to the stainless steel/titanium prosthesis. Furthermore, the results showed that the von Mises stress, principal stress, and the strain in the carbon/PEEK composites prosthesis were significantly lower than that made of the stainless steel/titanium. The results also imply that the carbon/PEEK composites can be applied to introduce a new optimum design for femoral prosthesis with adjustable stiffness, which can decrease the stress shielding and interface stress. These findings will help clinicians and biomedical experts to increase their knowledge about the hip replacement.

  11. Comparison between PEEK and Ti6Al4V concerning micro-scale abrasion wear on dental applications.

    PubMed

    Sampaio, M; Buciumeanu, M; Henriques, B; Silva, F S; Souza, J C M; Gomes, J R

    2016-07-01

    In the oral cavity, abrasive wear is predictable at exposed tooth or restorative surfaces, during mastication and tooth brushing. Also, wear can occur at contacting surfaces between the Ti-based prosthetic structures and implants in presence of abrasive compounds from food or toothpaste. Thus, the aim of this work was to compare the abrasive wear resistance of PEEK and Ti6Al4V on three-body abrasion related to different hydrated silica content and loads. Surfaces of Ti6Al4V or PEEK cylinders (8mm diameter and 4mm height) were wet ground on SiC papers and then polished with 1µm diamond paste. After that, surfaces were ultrasonically cleaned in propyl alcohol for 15min and then in distilled water for 10min. Micro-scale abrasion tests were performed at 60rpm and on different normal loads (0.4, 0.8 or 1.2N) after 600 ball revolutions using suspensions with different weight contents of hydrated silica. After abrasive tests, wear scars on flat samples were measured to quantify the wear volume and characterized by scanning electron microscope (SEM) to identify the dominant wear mechanisms. Results showed a higher volume loss rate on PEEK than that recorded on Ti6Al4V,, when subjected to three-body abrasion tests involving hydrated silica suspensions. An increase in volume loss was noted on both tested materials when the abrasive content or load was increased. PEEK was characterized by less wear resistance than that on Ti6Al4V after micro-scale abrasion wear in contact with hydrated silica particles, as commonly found in toothpastes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Cervical spondylosis (image)

    MedlinePlus

    Cervical spondylosis is a disorder that results from abnormal growth of the bones of the neck and ... Progressive neck pain is a key indication of cervical spondylosis. It may be the only symptom in ...

  13. Cervical Dystonia (Spasmodic Torticollis)

    MedlinePlus

    Cervical dystonia Overview By Mayo Clinic Staff Cervical dystonia, also called spasmodic torticollis, is a painful condition in which your neck muscles contract involuntarily, causing your head to twist or turn ...

  14. Cervical dysplasia - series (image)

    MedlinePlus

    Conization is a procedure in which a "cone" of tissue is removed. This procedure is performed for more advanced cervical dysplasia, which remains limited to the cervix (cervical intraepithelial neoplasia, high ...

  15. A new anterior-posterior surgical approach for the treatment of cervical facet dislocations.

    PubMed

    Wang, Biao; Zhu, Yue; Jiao, Ying; Wang, Feng; Liu, Xinchun; Zhu, Haitao; Tu, Guanjun; Liang, Deyong

    2014-05-01

    The preliminary results from a new anterior-posterior surgical approach are reported. To report a novel surgical approach, which was successfully applied to treat 8 cervical facet dislocation patients. The combined anterior-posterior surgical procedure is used as a common approach in the treatment of cervical facet dislocations. However, some problems may arise during the application of this approach, and as a result, surgeons must change the initial surgical plan to anterior-posterior-anterior approach. Between December 2011 and June 2012, 8 patients had facet dislocations were surgically treated by the new anterior-posterior approach. After anterior discectomy, a peek frame cage containing autologous iliac bone particles or tricalcium phosphate bone substitute was inserted in the interspace and fixed with a peek composite buttress plate screwed into the inferior vertebral body. Then, the anterior wound was closed and the patient was turned prone. Through a posterior midline approach, the posterior elements were exposed and the reduction was gradually achieved by posteriorly translating the superior segment and progressively positioning the patient's neck into extension. Then lateral mass or pedicle screws and titanium rods were placed in a favorable and satisfactory position, which was demonstrated by the intraoperative plain radiographs. A posterolateral fusion was performed and the posterior wound was closed. With the use of this new approach, all the patients had obtained successful reduction and satisfactory anatomic sagittal alignment. No instances of neurological deterioration and instrument failure occurred, no complications were owing to the use of this technique, and 4 patients existed neurological functional recovery at the most recent follow-up visit. This reported surgical approach is an efficient and safe way for the treatment of traumatic cervical facet dislocations.

  16. [Cervical ranula].

    PubMed

    Geurts, T W; van den Akker, H P; Balm, A J

    2004-02-21

    Three patients, 2 men aged 21 and 39 years, respectively, and 1 woman aged 29 years, presented with a unilateral swelling of the neck, with no accompanying symptoms. In the youngest man the diagnosis of a 'plunging ranula' was made after repeated fine needle aspiration yielded viscous yellowish mucus with a high amylase content. In the oldest man the diagnosis was made during the operation and in the woman the diagnosis was finally made after two surgical explorations in the neck. In all 3, no recurrence occurred after removal of the involved salivary glands. A cervical ranula is an extension of a pseudocyst of the glandula sublingualis. Important clues for the diagnosis of a 'plunging ranula' are: the simultaneous presence of a ranula in the floor of the mouth (or a history of one), a characteristic cystic mass in the submandibular space with an extension into the sublingual space on CT and/or MRI, and the aspiration of amylase-containing mucus. Excision of the sublingual gland as the source of salivary leakage is the therapy of choice in a case of 'plunging ranula', with drainage of mucus from the ranula into the oral cavity. As the 'plunging ranula' represents a pseudocyst without an epithelial lining, excision is not indicated.

  17. A new interpretation of SAXS peaks in sulfonated poly(ether ether ketone) (sPEEK) membranes for fuel cells.

    PubMed

    Mendil-Jakani, H; Zamanillo Lopez, I; Legrand, P M; Mareau, V H; Gonon, L

    2014-06-21

    The structure of a commercial sulfonated poly(ether ether ketone) (sPEEK) membrane was analyzed by Small-Angle X-Ray Scattering (SAXS) for different water uptakes obtained after immersion in liquid water at various temperatures. For low membrane swelling, the SAXS profile displays only a wide-angle peak in the 0.2-0.3 Å(-1) region. As the membrane swells, two supplementary correlation peaks arise and shift towards small angles, which are the signature of a structural evolution of the membrane, whereas the wide angle peak remains stable. The SAXS spectra of sPEEK membranes can thus display three correlation peaks simultaneously. Therefore we propose a new interpretation of these SAXS spectra which conclude that the two small angle peaks are attributed to the so-called matrix and ionomer peaks and the wide-angle peak is ascribed to the mean separation distance between sulfonic acid groups grafted onto the polymer backbone. This peak attribution implies that the sPEEK nano-phase separation is triggered by an immersion in hot water (ionomer peak apparition). Our new peak attribution was confirmed by studying the impact of temperature, electron density contrast and ionic exchange capacity.

  18. Nucleation and growth of apatite on NaOH-treated PEEK, HDPE and UHMWPE for artificial cornea materials.

    PubMed

    Pino, M; Stingelin, N; Tanner, K E

    2008-11-01

    The skirt of an artificial cornea must integrate the implant to the host sclera, a major failure of present devices. Thus, it is highly desirable to encourage the metabolic activity of the cornea by using more bioactive, flexible skirt materials. Here we describe attempts to increase the bioactivity of polyether ether ketone (PEEK), high-density polyethylene (HDPE) and ultra-high molecular weight polyethylene (UHMWPE) films. The effectiveness of different strength NaOH pre-treatments to initiate apatite deposition on PEEK, HDPE and UHMWPE is investigated. We find that exposure of PEEK, HDPE and UHMWPE films to NaOH solutions induces the formation of potential nuclei for apatite (calcium phosphate), from which the growth of an apatite coating is stimulated when subsequently immersing the polymer films in 1.5 strength Simulated Body Fluid (SBF). As immersion time in SBF increases, further nucleation and growth produces a thicker and more compact apatite coating that can be expected to be highly bioactive. Interestingly, the apatite growth is found to also be dependent on both the concentration of NaOH solution and the structure of the polymer surface.

  19. Results of the radiological and beryllium verification survey at the Peek Street Site, Schenectady, New York (SY001V)

    SciTech Connect

    Foley, R.D.; Johnson, C.A.; Carrier, R.F.; Allred, J.F.

    1994-10-01

    At the request of the U.S. Department of Energy (DOE), a team from Oak Ridge National Laboratory conducted an independent verification radiological and non-radioactive beryllium survey at the Peek Street site, located at 425 Peek Street, Schenectady, New York. The purpose of the survey, conducted during 1993 and continuing through January 1994, was to confirm the success of the remedial actions performed to remove any beryllium concentrations or radioactive materials in excess of the identified guidelines. The verification survey included surface gamma scans and gamma readings at one meter indoors and outdoors, alpha and beta scans inside the structure, and the collection of soil, dust and debris samples and smears for radionuclide and beryllium analyses. Results of the survey demonstrated that all radiological and beryllium measurements on the property were within applicable DOE guidelines. Based on all data collected, the industrial property at 425 Peek Street and the adjacent state-owned bike path in Schenectady, New York, conforms to all applicable radiological and non-radioactive beryllium guidelines established for this site by DOE and approved by the State of New York.

  20. [Cervical spine and pain].

    PubMed

    Cimen, Ali

    2007-04-01

    Chronic pain originating from the cervical spine, that may have diverse etiological factors, is a common condition in the clinical practice. Having distinct properties in the spine, cervical column has a wide range of motion and is commonly subject to traumatic injury. In this review, after the anatomical properties that has clinical significance and the evaluation of a patient with cervical pain are explained, the common cervical spinal pain conditions are discussed by emphasizing the therapeutic approaches in each condition.

  1. Veliparib, Topotecan Hydrochloride, and Filgrastim or Pegfilgrastim in Treating Patients With Persistent or Recurrent Cervical Cancer

    ClinicalTrials.gov

    2016-12-07

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Small Cell Carcinoma; Cervical Squamous Cell Carcinoma; Recurrent Cervical Carcinoma; Stage III Cervical Cancer; Stage IVA Cervical Cancer; Stage IVB Cervical Cancer

  2. Preinduction cervical assessment.

    PubMed

    Baacke, Keri A; Edwards, Rodney K

    2006-09-01

    The rate of labor induction is increasing in the United States. Methods for quantifying cervical factors have been developed to identify patients who may benefit from cervical ripening before induction. The first cervical scoring systems used digital examination. More recently, cervical ultrasound and testing for the presence of fetal fibronectin have been suggested to evaluate cervical readiness for labor induction, but neither of these methods provides a significant improvement over digital examination. The Bishop score, the most widely used digital examination scoring system, still is the most cost effective and accurate method of evaluating the cervix before labor induction.

  3. Vaccines against cervical cancer.

    PubMed

    Jansen, Kathrin U

    2004-11-01

    Cervical cancer and precancerous lesions of the genital tract are a major threat to women's health worldwide. Although the introduction of screening tests to detect cervical cancer and its precursor lesions has reduced overall cervical cancer rates in the developed world, the approach was largely unsuccessful for developing countries, primarily due to a lack of appropriate infrastructures and high costs. Annually, 470,000 cervical cancer cases are diagnosed worldwide, of which 80% occur in developing countries. Despite advances in treatment of cervical cancer, approximately half of the women afflicted with the disease will die. Over 20 years of dedicated research has provided conclusive evidence that a subset of human papillomaviruses are the aetiological agents for cervical cancer. Finding a viral origin for this disease provided the basis to fight cervical cancer using prophylactic or therapeutic vaccination. Both vaccine approaches are reviewed here, with an emphasis on recent clinical data.

  4. ADXS11-001 High Dose HPV+ Cervical Cancer

    ClinicalTrials.gov

    2016-06-17

    Effects of Immunotherapy; Metastatic/Recurrent Cervical Cancer; Cervical Adenocarcinoma; Cervical Adenosquamous Cell Carcinoma; Cervical Squamous Cell Carcinoma; Cervical Small Cell Carcinoma; Stage III Cervical Cancer; Stage IVA Cervical Cancer; Stage IVB Cervical Cancer

  5. Characterization of Mode I and Mode II delamination growth and thresholds in AS4/PEEK composites

    NASA Technical Reports Server (NTRS)

    Martin, Roderick H.; Murri, Gretchen Bostaph

    1990-01-01

    Composite materials often fail by delamination. The onset and growth of delamination in AS4/PEEK, a tough thermoplastic matrix composite, was characterized for mode 1 and mode 2 loadings, using the Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) test specimens. Delamination growth per fatigue cycle, da/dN, was related to strain energy release rate, G, by means of a power law. However, the exponents of these power laws were too large for them to be adequately used as a life prediction tool. A small error in the estimated applied loads could lead to large errors in the delamination growth rates. Hence strain energy release rate thresholds, G sub th, below which no delamination would occur were also measured. Mode 1 and 2 threshold G values for no delamination growth were found by monitoring the number of cycles to delamination onset in the DCB and ENF specimens. The maximum applied G for which no delamination growth had occurred until at least 1,000,000 cycles was considered the threshold strain energy release rate. Comments are given on how testing effects, facial interference or delamination front damage, may invalidate the experimental determination of the constants in the expression.

  6. Characterization of Mode I and Mode II delamination growth and thresholds in AS4/PEEK composites

    NASA Technical Reports Server (NTRS)

    Martin, Roderick H.; Murri, Gretchen Bostaph

    1990-01-01

    Composite materials often fail by delamination. The onset and growth of delamination in AS4/PEEK, a tough thermoplastic matrix composite, was characterized for mode 1 and mode 2 loadings, using the Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) test specimens. Delamination growth per fatigue cycle, da/dN, was related to strain energy release rate, G, by means of a power law. However, the exponents of these power laws were too large for them to be adequately used as a life prediction tool. A small error in the estimated applied loads could lead to large errors in the delamination growth rates. Hence strain energy release rate thresholds, G sub th, below which no delamination would occur were also measured. Mode 1 and 2 threshold G values for no delamination growth were found by monitoring the number of cycles to delamination onset in the DCB and ENF specimens. The maximum applied G for which no delamination growth had occurred until at least 1,000,000 cycles was considered the threshold strain energy release rate. Comments are given on how testing effects, facial interference or delamination front damage, may invalidate the experimental determination of the constants in the expression.

  7. High-strain-rate characterization of TPOs and graphite/epoxy and graphite/peek composites

    NASA Astrophysics Data System (ADS)

    Brar, N. S.; Simha, H.; Pratap, A.

    2001-06-01

    Tensile and compressive stress-strain response of two types of TPOs and graphite-epoxy composites are investigated at strain rates in the range 0.001/s-1000/s. Specimen strain in the low strain rate regime 0.001-100/s was determined using an optical extensometer in conjunction with standard MTS machine. Tensile test at high strain rate were performed on newly developed tensile version of All- Polymeric Split Hopkinson Bar. Tensile TPO specimens in the dog-bone configuration are placed in specially designed grips fabricated from nylatron. Compression response of TPO specimens at high strain rate is determined using 25.4-mm diameter aluminum bars. Peak compressive stress increases from 10 MPa at a strain rate of 100/s to 35 MPa at a strain rate of 1000/s. Preliminary data on high strain rate tensile response of graphite-epoxy and graphite-peek composites are presented. These data are intended to develop a material model incorporating strain rate sensitivity for TPOs and to be used in car crash simulations.

  8. Reflectance measurements of PTFE, Kapton, and PEEK for xenon scintillation light for the LZ detector.

    NASA Astrophysics Data System (ADS)

    Arthurs, M.; Batista, E.; Haefner, J.; Lorenzon, W.; Morton, D.; Neff, A.; Okunawo, M.; Pushkin, K.; Sander, A.; Stephenson, S.; Wang, Y.; LZ Collaboration

    2017-01-01

    LZ (LUX-Zeplin) is an international collaboration that will look for dark matter candidates, WIMPs (Weakly Interacting Massive Particles), through direct detection by dual-phase time projection chamber (TPC) using liquid xenon. The LZ detector will be located nearly a mile underground at SURF, South Dakota, shielded from cosmic background radiation. Seven tons active mass of liquid xenon will be used for detecting the weak interaction of WIMPs with ordinary matter. Over three years of operation it is expected to reach the ultimate sensitivity of 2x10-48 cm2 for a WIMP mass of 50 GeV. As for many other rare event searches, high light collection efficiency is essential for LZ detector. Moreover, in order to achieve greater active volume for detection as well as reduce potential backgrounds, thinner detector walls without significant loss in reflectance are desired. Reflectance measurements of polytetrafluoroethylene (PTFE), Kapton, and PEEK for xenon scintillation light (178 nm), conducted at the University of Michigan using the Michigan Xenon Detector (MiX) will be presented. The University of Michigan, LZ Collaboration, The US Department of Energy.

  9. Characterization of Mode 1 and Mode 2 delamination growth and thresholds in graphite/peek composites

    NASA Technical Reports Server (NTRS)

    Martin, Roderick H.; Murri, Gretchen B.

    1988-01-01

    Composite materials often fail by delamination. The onset and growth of delamination in AS4/PEEK, a tough thermoplastic matrix composite, was characterized for mode 1 and mode 2 loadings, using the Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) test specimens. Delamination growth per fatigue cycle, da/dN, was related to strain energy release rate, G, by means of a power law. However, the exponents of these power laws were too large for them to be adequately used as a life prediction tool. A small error in the estimated applied loads could lead to large errors in the delamination growth rates. Hence strain energy release rate thresholds, G sub th, below which no delamination would occur were also measured. Mode 1 and 2 threshold G values for no delamination growth were found by monitoring the number of cycles to delamination onset in the DCB and ENF specimens. The maximum applied G for which no delamination growth had occurred until at least 1,000,000 cycles was considered the threshold strain energy release rate. Comments are given on how testing effects, facial interference or delamination front damage, may invalidate the experimental determination of the constants in the expression.

  10. Processing parameters for filament winding thick-section PEEK/carbon fiber composites

    NASA Astrophysics Data System (ADS)

    Colton, J.; Leach, D.

    1992-12-01

    The consolidation pressure and winding speed for thermoplastic filament winding were studied. Thermoplastic composite parts were manufactured from tape prepreg (APC-2); powder-coated, semi-consolidated towpreg; and commingled fiber towpreg. The material used was carbon fiber (AS-4) (60 vol pct) in a PEEK matrix. The parts made were open-ended cylinders of the three materials, 177.8-mm ID, 228.6 mm long, 17 plies thick with a 0 deg lay-up angle; and rings, 50 plies of APC-2 thick, 6.35 mm wide (one strip wide), 177.8-mm ID, and a lay-up of 0 deg. Their quality was determined by surface finish and void percentage. The tubes made from APC-2 appeared to have the best quality of the three prepregs. For the rings, the speed of lay-down had a significant effect on both the final width of the parts and on the percentage of voids. The pressure of the roller had a significant effect on the final widths at a 99 percent confidence level, but a significant effect on the percentage of voids at only a 95 percent confidence level.

  11. High temperature dielectric properties of Apical, Kapton, Peek, Teflon AF, and Upilex polymers

    NASA Technical Reports Server (NTRS)

    Hammoud, A. N.; Baumann, E. D.; Overton, E.; Myers, I. T.; Suthar, J. L.; Khachen, W.; Laghari, J. R.

    1992-01-01

    Reliable lightweight systems capable of providing electrical power at the magawatt level are a requirement for future manned space exploration missions. This can be achieved by the development of high temperature insulating materials which are not only capable of surviving the hostile space environment but can contribute to reducing the mass and weight of the heat rejection system. In this work, Apical, Upilex, Kapton, Teflon AF, and Peek polymers are characterized for AC and DC dielectric breakdown in air and in silicone oil at temperatures up to 250 C. The materials are also tested in terms of their dielectric constant and dissipation factor at high temperatures with an electrical stress of 60 Hz, 200 V/mil present. The effects of thermal aging on the properties of the films are determined after 15 hours of exposure to 200 and 250 C, each. The results obtained are discussed and conclusions are made concerning the suitability of these dielectrics for use in capacitors and cable insulations in high temperature environments.

  12. Pullout performance comparison of novel expandable pedicle screw with expandable poly-ether-ether-ketone shells and cement-augmented pedicle screws.

    PubMed

    Aycan, Mehmet Fatih; Tolunay, Tolga; Demir, Teyfik; Yaman, Mesut Emre; Usta, Yusuf

    2017-02-01

    Aim of this study is to assess the pullout performance of various pedicle screws in different test materials. Polyurethane foams (Grade 10 and Grade 40) produced in laboratory and bovine vertebrae were instrumented with normal, cannulated (cemented), novel expandable and normal (cemented) pedicle screws. Test samples were prepared according to the ASTM F543 standard testing protocols and surgical guidelines. To examine the screw placement and cement distribution, anteriosuperior and oblique radiographs were taken from each sample after insertion process was completed. Pullout tests were performed in an Instron 3369 testing device. Load versus displacement graphs were recorded and the ultimate pullout force was defined as the maximum load (pullout strength) sustained before failure of screw. Student's t-test was performed on each group whether the differences between pullout strength of pedicle screws were significant or not. While normal pedicle screws have the lowest pullout strength in all test materials, normal pedicle screws cemented with polymethylmethacrylate exhibit significantly higher pullout performance than others. For all test materials, there is a significant improvement in pullout strength of normal screws by augmentation. While novel expandable pedicle screws with expandable poly-ether-ether-ketone shells exhibited lower pullout performance than normal screws cemented with polymethylmethacrylate, their pullout performances in all groups were higher than the ones of normal and cannulated pedicle screws. For all test materials, although cannulated pedicle screws exhibit higher pullout strength than normal pedicle screws, there are no significant differences between the two groups. The novel expandable pedicle screws with expandable poly-ether-ether-ketone shells may be used instead of normal and cannulated pedicle screws cemented with polymethylmethacrylate due to their good performances.

  13. Signs and Symptoms of Cervical Cancer

    MedlinePlus

    ... Detection, Diagnosis, and Staging Signs and Symptoms of Cervical Cancer Women with early cervical cancers and pre- ... Ask Your Doctor About Cervical Cancer? More In Cervical Cancer About Cervical Cancer Causes, Risk Factors, and ...

  14. The impact of argon/oxygen low-pressure plasma on shear bond strength between a veneering composite and different PEEK materials.

    PubMed

    Schwitalla, Andreas Dominik; Bötel, Friederike; Zimmermann, Tycho; Sütel, Mona; Müller, Wolf-Dieter

    2017-09-01

    The aim of the study was to evaluate the impact of low-pressure argon/oxygen plasma with and without previous sandblasting on the shear bond strength (SBS) between dental PEEK compounds and a veneering composite. Of one type of unfilled PEEK and two pigment powder filled PEEK compounds, forty rectangular plates each were prepared and polished up to 4000 grit. The samples were randomly assigned to four surface pre-treatment groups, each consisting of ten specimens (1. Untreated; 2. Plasma treatment; 3. Sandblasting; 4. Sandblasting+plasma treatment). Plasma treatment was performed for 35min using a low-pressure plasma system with a 1:1 mixture of the process gases argon and oxygen. Surface roughness and water contact angles were recorded. An adhesive (Visio.link, Bredent GmbH & Co KG, Senden, Germany) was applied onto the specimen surfaces and light cured. A mold was used to shape the veneering composite (Vita VM LC, Vita Zahnfabrik, Bad Säckingen, Germany) into a cylindrical form on the sample surface before light curing. SBS was measured after 24h incubation at 37°C in distilled water using a universal testing machine. The samples pre-treated according to group 4 (sandblasting and plasma treatment) showed the highest SBS overall, whereas the unfilled PEEK showed the highest SBS (19.8±2.46MPa) compared to the other PEEK materials (15.86±4.39MPa and 9.06±3.1MPa). Sandblasting and surface activation with low-pressure argon/oxygen plasma in combination with an adhesive causes a favorable increase in shear bond strength, especially on unfilled PEEK material. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  15. Effectiveness of a novel mobile health education intervention (Peek) on spectacle wear among children in India: study protocol for a randomized controlled trial.

    PubMed

    Morjaria, Priya; Bastawrous, Andrew; Murthy, Gudlavalleti Venkata Satyanarayana; Evans, Jennifer; Gilbert, Clare

    2017-04-08

    Uncorrected refractive errors are the commonest cause of visual loss in children despite spectacle correction being highly cost-effective. Many affected children do not benefit from correction as a high proportion do not wear their spectacles. Reasons for non-wear include parental attitudes, overprescribing and children being teased/bullied. Most school programmes do not provide health education for affected children, their peers, teachers or parents. The Portable Eye Examination Kit (Peek) will be used in this study. Peek has applications for measuring visual acuity with software for data entry and sending automated messages to inform providers and parents. Peek also has an application which simulates the visual blur of uncorrected refractive error (SightSim). The hypothesis is that higher proportion of children with uncorrected refractive errors in schools allocated to the Peek educational package will wear their spectacles 3-4 months after they are dispensed, and a higher proportion of children identified with other eye conditions will access services, compared with schools receiving standard school screening. Cluster randomized, double-masked trial of children with and without uncorrected refractive errors or other eye conditions. Government schools in Hyderabad, India will be allocated to intervention (Peek) or comparator (standard programme) arms before vision screening. In the intervention arm Peek will be used for vision screening, SightSim images will be used in classroom teaching and will be taken home by children, and voice messages will be sent to parents of children requiring spectacles or referral. In both arms the same criteria for recruitment, prescribing and dispensing spectacles will be used. After 3-4 months children dispensed spectacles will be followed up to assess spectacle wear, and uptake of referrals will be ascertained. The cost of developing and delivering the Peek package will be assessed. The cost per child wearing their spectacles or

  16. Derivation of beryllium guidelines for use in establishing cleanup levels at the Peek Street and Sacandaga sites, New York

    SciTech Connect

    Hartmann, H.M.; Avci, H.I.; Ditmars, J.D.

    1992-02-01

    Guideline levels are derived for beryllium in soil and on indoor surfaces at the Peek Street and Sacandaga sites in the state of New York. On the basis of highly conservative assumptions, the soil beryllium concentration that corresponds to a 10{sup {minus} 4} carcinogenic risk level is estimated to be 13 mg/kg at both sites. Calculations indicate that the proposed US Department of Energy guideline of 2 {mu}g/ft{sup 2} for beryllium in dust on indoor surfaces would be sufficiently protective of human health. For occupational protection of workers during cleanup operations, Office of Safety and Health Administration standards for beryllium are referenced and restated.

  17. SAXS Study and Thermal Analysis of Two-Stage Melt Crystallization of PEEK

    NASA Astrophysics Data System (ADS)

    Georgiev, Georgi; Dai, Patrick; Oyebode, Elizabeth; Cebe, Peggy; Capel, Malcolm

    1998-03-01

    We have been studying dual stage melt crystalization of PEEK using a treatment scheme involving annealing/crystallization at Ta1 followed by annealing/crystallization at Ta2, where either Ta1Ta2. We compare single and double stages of melt crystallization using differential scanning calorimetry (DSC) and small angle X-ray scattering (SAXS). Double stage crystallization was used to study the relative perfection of the crystals formed from the melt. The samples were heated to 375 C in a Mettler hot stage and were held there for three minutes so as to erase the crystals from previous treatments before cooling to 280 C. Crystallization occurred rapidly during cooling below 300 C. The samples were held for ten minutes at Ta1=280 C before being heated to the annealing temperature, Ta2=295 C, where they were held at for a period of time, t( t = 0, 1, 3.5, or 10 min. ),and then immediately heated to 360 C. We observe a double peak in SAXS intensity. During the isothermal periods, the intensity of the major peak at lower scattering vector, s, stays constant. A shoulder grows up on the high side of the major peak, and increases in intensity with the holding time at 280 C. During heating from below to above of the minor melting endotherm, the intensity in the high s shoulder decreases. After the sample is annealed at 295 C, the shoulder intensity is restored once again. The population scattering at higher s remains longer before it disappears in the sample treated to the second stage of melt crystallization, compare to the sample crystallized with a single stage. Research was supported by the National Aeronautics and Space Administration, Grant NAG8

  18. Mechanical Properties of Plasma Immersion Ion Implanted PEEK for Bioactivation of Medical Devices.

    PubMed

    Wakelin, Edgar A; Fathi, Ali; Kracica, Masturina; Yeo, Giselle C; Wise, Steven G; Weiss, Anthony S; McCulloch, Dougal G; Dehghani, Fariba; Mckenzie, David R; Bilek, Marcela M M

    2015-10-21

    Plasma immersion ion implantation (PIII) is used to modify the surface properties of polyether ether ketone for biomedical applications. Modifications to the mechanical and chemical properties are characterized as a function of ion fluence (treatment time) to determine the suitability of the treated surfaces for biological applications. Young's modulus and elastic recovery were found to increase with respect to treatment time at the surface from 4.4 to 5.2 MPa and from 0.49 to 0.68, respectively. The mechanical properties varied continuously with depth, forming a graded layer where the mechanical properties returned to untreated values deep within the layer. The treated surface layer exhibited cracking under cyclical loads, associated with an increased modulus due to dehydrogenation and cross-linking; however, it did not show any sign of delamination, indicating that the modified layer is well integrated with the substrate, a critical factor for bioactive surface coatings. The oxygen concentration remained unchanged at the surface; however, in contrast to ion implanted polymers containing only carbon and hydrogen, the oxygen concentration within the treated layer was found to decrease. This effect is attributed to UV exposure and suggests that PIII treatments can modify the surface to far greater depths than previously reported. Protein immobilization on PIII treated surfaces was found to be independent of treatment time, indicating that the surface mechanical properties can be tuned for specific applications without affecting the protein coverage. Our findings on the mechanical properties demonstrate such treatments render PEEK well suited for use in orthopedic implantable devices.

  19. Peeking into Saturn's Atmosphere: the HST Low-Phase Angle View

    NASA Astrophysics Data System (ADS)

    Perez-Hoyos, S.; Sanz-Requena, J. F.; Sanchez-Lavega, A.; Hueso, R.; del Rio-Gaztelurrutia, T.; Rojas, J. F.; Simon, A. A.; Wong, M. H.; De Pater, I.; Irwin, P. G.

    2015-12-01

    Recent Hubble Space Telescope WFC3 observations of Saturn have provided a low-phase angle view of the planet that complements the higher phase angles and increased spatial resolution view from the Cassini spacecraft. HST orbits were perfectly timed for observing an atmospheric perturbation at polar latitudes that has been conspicuous on ground-based observations of the planet since May 2015. The observations serendipitously captured other interesting features at the Equatorial Zone (EZ) with Voyager-era fast speeds (see Sánchez-Lavega et al. abstract, this meeting). In this presentation we will discuss how the synergy between the Cassini/ISS and HST/WFC3 observations provides an excellent way for peeking into Saturn's atmosphere and analyze the vertical distribution and properties of the particles and aerosols located in the lower stratosphere and upper troposphere of the planet. We first discuss how Cassini/ISS observations at a variety of phase angles constrain particle properties and phase functions, in particular at the Equatorial Zone where they resemble 100 micron ammonia ice crystals. With this information, it is possible to use the HST/WFC3 observations at 10 filters from near-ultraviolet to the near-infrared provide substantial information on the vertical cloud structure and composition: the filters in and out of the intermediate and deep methane bands at the near infrared give information on particle number density around the tropopause level and down to the ammonia condensation level, while near-ultraviolet and blue filters characterize the absorption of unknown chromophores in Saturn's atmosphere. Fast-moving features in the EZ are found to be located deeper (> 2 bar) than the features used for cloud-tracking since the pre-Cassini era (< 1 bar). This provides an unprecedented view of the EZ vertical wind shear by sounding simultaneously three separate atmospheric levels. Finally, results for Saturn's Northern hemisphere will also be showed.

  20. 4. Cervical radicular pain.

    PubMed

    Van Zundert, Jan; Huntoon, Marc; Patijn, Jacob; Lataster, Arno; Mekhail, Nagy; van Kleef, Maarten

    2010-01-01

    Cervical radicular pain is defined as pain perceived as arising in the arm caused by irritation of a cervical spinal nerve or its roots. Approximately 1 person in 1,000 suffers from cervical radicular pain. In the absence of a gold standard, the diagnosis is based on a combination of history, clinical examination, and (potentially) complementary examination. Medical imaging may show abnormalities, but those findings may not correlate with the patient's pain. Electrophysiologic testing may be requested when nerve damage is suspected but will not provide quantitative/qualitative information about the pain. The presumed causative level may be confirmed by means of selective diagnostic blocks. Conservative treatment typically consists of medication and physical therapy. There are no studies assessing the effectiveness of different types of medication specifically in patients suffering cervical radicular pain. Cochrane reviews did not find sufficient proof of efficacy for either education or cervical traction. When conservative treatment fails, interventional treatment may be considered. For subacute cervical radicular pain, the available evidence on efficacy and safety supports a recommendation (2B+) of interlaminar cervical epidural corticosteroid administration. A recent negative randomized controlled trial of transforaminal cervical epidural corticosteroid administration, coupled with an increasing number of reports of serious adverse events, warrants a negative recommendation (2B-). Pulsed radiofrequency treatment adjacent to the cervical dorsal root ganglion is a recommended treatment for chronic cervical radicular pain (1B+). When its effect is insufficient or of short duration, conventional radiofrequency treatment is recommended (2B+). In selected patients with cervical radicular pain, refractory to other treatment options, spinal cord stimulation may be considered. This treatment should be performed in specialized centers, preferentially study related.

  1. Atezolizumab and Bevacizumab in Treating Patients With Recurrent, Persistent, or Metastatic Cervical Cancer

    ClinicalTrials.gov

    2017-09-28

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma, Not Otherwise Specified; Recurrent Cervical Carcinoma; Stage IV Cervical Cancer; Stage IVA Cervical Cancer; Stage IVB Cervical Cancer

  2. Bevacizumab, Radiation Therapy, and Cisplatin in Treating Patients With Previously Untreated Locally Advanced Cervical Cancer

    ClinicalTrials.gov

    2014-09-22

    Cervical Adenocarcinoma; Cervical Adenosquamous Cell Carcinoma; Cervical Squamous Cell Carcinoma; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer

  3. Cervical Cancer Stage IB

    MedlinePlus

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IB Add to My Pictures View / ... 1613x1200 View Download Large: 3225x2400 View Download Title: Cervical Cancer Stage IB Description: Stage IB1 and IB2 ...

  4. Cervical Cancer Stage IA

    MedlinePlus

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IA Add to My Pictures View / ... 1500x1200 View Download Large: 3000x2400 View Download Title: Cervical Cancer Stage IA Description: Stage IA1 and IA2 ...

  5. Cervical Cancer Prevention

    MedlinePlus

    ... oral contraceptives, over a 10 year period, the risk of cervical cancer returns to that of women who never used oral contraceptives. Smoking cigarettes Among women who are infected with HPV, ... smoke have an increased risk of cervical cancer. The risk increases with the ...

  6. Rat embryonic liver cell expansion and differentiation on NH3 plasma-grafted PEEK-WC-PU membranes.

    PubMed

    Pavlica, Sanja; Piscioneri, Antonella; Peinemann, Frank; Keller, Mario; Milosevic, Javorina; Staeudte, Andrea; Heilmann, Andreas; Schulz-Siegmund, Michaela; Laera, Stefania; Favia, Pietro; De Bartolo, Loredana; Bader, Augustinus

    2009-11-01

    Biomaterials can potentially influence stem and progenitor cell proliferation and differentiation in both a positive and a negative way. Herein, we report on the expansion and differentiation of rat embryonic (E17) liver (RLC-18) cells on new bioactive membrane made of PEEK-WC-PU, whose surface was grafted with nitrogen functionalities by means of NH(3) glow discharges. The performance of the developed membrane was evaluated by analyzing the expression of the liver specific functions of cells cultured in a 6-well gas-permeable bioreactor. It was found that native and NH(3) plasma-grafted PEEK-WC-PU membranes enabled expansion of liver cells in the bioreactor. Liver embryonic cells on the membranes exhibited higher functional activities compared to those cultured on conventional culture dishes as demonstrated by higher albumin and urea production. They showed gene expression of alpha-fetoprotein and albumin in a time-dependent manner of the hepatic differentiation process. LDH assay and SEM analyses revealed that a high number of viable liver stem cells attached to the membranes. Unexpectedly, liver progenitors cultured on membranes had higher telomerase activity than ones in the plates, preventing cell senescence. Thus, membranes are able to sustain in vitro the same in vivo liver functions and to allow the expansion of progenitor cells.

  7. Non-Invasive Cervical Cancer Radiotherapy for Stage IB-IVB

    ClinicalTrials.gov

    2017-05-16

    Cervical Cancer; Cervical Cancer Stage; Cervical Cancer Stage IB2; Cervical Cancer Stage IB1; Cervical Cancer Stage I; Cervical Cancer Stage IB; Cervical Cancer Stage II; Cervical Cancer Stage IIa; Cervical Cancer, Stage IIB; Cervical Cancer, Stage III; Cervical Cancer Stage IIIB; Cervical Cancer Stage IIIA; Cervical Cancer Stage Iv; Cervical Cancer Stage IVA; Cervical Cancer Stage IVB

  8. PEEK-OPTIMA(™) as an alternative to cobalt chrome in the femoral component of total knee replacement: A preliminary study.

    PubMed

    Cowie, Raelene M; Briscoe, Adam; Fisher, John; Jennings, Louise M

    2016-11-01

    PEEK-OPTIMA(™) (Invibio Ltd, UK) has been considered as an alternative joint arthroplasty bearing material due to its favourable mechanical properties and the biocompatibility of its wear debris. In this study, the potential to use injection moulded PEEK-OPTIMA(™) as an alternative to cobalt chrome in the femoral component of a total knee replacement was investigated in terms of its wear performance. Experimental wear simulation of three cobalt chrome and three PEEK-OPTIMA(™) femoral components articulating against all-polyethylene tibial components was carried out under two kinematic conditions: 3 million cycles under intermediate kinematics (maximum anterior-posterior displacement of 5 mm) followed by 3 million cycles under high kinematic conditions (anterior-posterior displacement 10 mm). The wear of the GUR1020 ultra-high-molecular-weight polyethylene tibial components was assessed by gravimetric analysis; for both material combinations under each kinematic condition, the mean wear rates were low, that is, below 5 mm(3)/million cycles. Specifically, under intermediate kinematic conditions, the wear rate of the ultra-high-molecular-weight polyethylene tibial components was 0.96 ± 2.26 mm(3)/million cycles and 2.44 ± 0.78 mm(3)/million cycle against cobalt chrome and PEEK-OPTIMA(™) implants, respectively (p = 0.06); under high kinematic conditions, the wear rates were 2.23 ± 1.85 mm(3)/million cycles and 4.44 ± 2.35 mm(3)/million cycles, respectively (p = 0.03). Following wear simulation, scratches were apparent on the surface of the PEEK-OPTIMA(™) femoral components. The surface topography of the femoral components was assessed using contacting profilometry and showed a statistically significant increase in measured surface roughness of the PEEK-OPTIMA(™) femoral components compared to the cobalt chrome implants. However, this did not appear to influence the wear rate, which remained linear over the

  9. The effects of anterior cervical discectomy and fusion with stand-alone cages at two contiguous levels on cervical alignment and outcomes.

    PubMed

    Moon, Hong Joo; Kim, Joo Han; Kim, Jong-Hyun; Kwon, Taek-Hyun; Chung, Hung-Seob; Park, Youn-Kwan

    2011-03-01

    Anterior cervical discectomy and fusion (ACDF) using stand-alone cages is an effective method of treating degenerative disease. However, stand-alone cages are reported to have a relatively high incidence of implant subsidence with secondary kyphotic deformity particularly after multilevel ACDF. The purpose of our article was to investigate clinical and radiological outcomes after ACDF using stand-alone cages, at two contiguous levels, with a particular focus on changes in regional alignment and the correlation between alignment of the operated cervical levels and the entire cervical spine. Twenty-seven patients with 54 levels and a mean age of 50.8 years were enrolled between January 2005 and August 2006. They underwent ACDF using polyetheretherketone cages packed with demineralized bone matrix without plate fixation at two contiguous levels. Mean follow-up period was 25.5 months (range, 13-60). Clinical outcome was evaluated using two Visual Analog Scales and the Neck Disability Index (NDI). We assessed fusion, regional alignment (RA) of the operated levels and cervical global alignment (GA) preoperatively in the immediate 1-week postoperative period and at the final follow-up. An interspinous distance ≥2 mm was used as an indicator of pseudoarthrosis at each level. All patients showed improvements in clinical outcome, with 96% of patients showing mild NDI scores (<14). Radiological solid fusion was obtained at 48 of 54 levels (88.9%) and in 21 of 27 patients (77.8%). Lower cervical levels were significantly more vulnerable to pseudoarthrosis (100%). Fusion rate had no significant correlation with outcome (p > 0.05). RA of the operated levels was improved at the final follow-up compared with preoperatively in 76% of patients, although it had decreased compared with the immediate postoperative period due to subsidence in 84% of patients. In total, 80.8% of patients showed improvements in GA. Furthermore, improvements in RA showed a significant positive

  10. [Isolated anterior cervical hypertrichosis].

    PubMed

    Monteagudo, B; Cabanillas, M; de las Heras, C; Cacharrón, J M

    2009-01-01

    Anterior cervical hypertrichosis was described by Trattner and coworkers in 1991. It consists of a of hair at the anterior cervical level just above the laryngeal prominence. To date, only 28 cases of anterior cervical hypertrichosis have been reported. Although it is normally an isolated finding, it may be associated with mental retardation, hallux valgus, retinal disorders, other hair disorders, facial dysmorphism, or sensory and motor peripheral neuropathy. We report the case of a 27-year-old woman who presented with this condition as an isolated finding.

  11. Immunotherapy for Cervical Cancer

    Cancer.gov

    In an early phase NCI clinical trial, two patients with metastatic cervical cancer had a complete disappearance of their tumors after receiving treatment with a form of immunotherapy called adoptive cell transfer.

  12. [Cervical pregnancy. Three cases].

    PubMed

    Plascencia Moncayo, Norberto; Hernández, María de la Paz; Guadarrama Sánchez, Rafael; Guerra Becerra, Leticia; Salmón Vélez, J Fernando G; Galván Aguilera, Alejandro

    2008-12-01

    We describe cervical pregnancy concept and its rareness. Its frequency is one in 2,550 to 98,000 intrauterine pregnancies. Predisposing factors are related with endometrial damage due to uterine curettages and previous cesarian section. Clinical picture was nonspecific and diagnosis was based in endovaginal ultrasonography. It can cause massive bleeding and put life in risk. During 2007 we attend 829 intrauterine pregnancies at Hospital San José de Querétaro: 11 tubal, and 3 cervical, this represents an extraordinarily high frequency of cervical pregnancy. Here we report three cases of cervical pregnancies treated with total hysterectomy, two as urgency and one elective. We remark early diagnosis importance to perform conservative treatment and maintain reproductive function.

  13. The cervical cap (image)

    MedlinePlus

    The cervical cap is a flexible rubber cup-like device that is filled with spermicide and self-inserted over the cervix ... left in place several hours after intercourse. The cap is a prescribed device fitted by a health ...

  14. Cervical Radiculopathy (Pinched Nerve)

    MedlinePlus

    ... soft, jelly-like center of the disk. Cause Cervical radiculopathy most often arises from degenerative changes that occur in the spine as we age or from an injury that causes a herniated, or bulging, intervertebral disk. ...

  15. Cervical Cancer Screening

    MedlinePlus

    ... cervical cancer in women aged 30–65 years. Human Immunodeficiency Virus (HIV): A virus that attacks certain cells of the body’s immune system and causes acquired immunodeficiency syndrome (AIDS). Human Papillomavirus ( ...

  16. Cervical Cancer - Multiple Languages

    MedlinePlus

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Cervical Cancer URL of this page: https://medlineplus.gov/languages/cervicalcancer.html Other topics A-Z Expand Section ...

  17. Sexually Transmitted Cervicitis

    PubMed Central

    Romanowski, Barbara

    1989-01-01

    Cervical infections with Neisseria gonorrhoeae, Chlamydia trachomatis, and Herpes simplex virus are some of the most common sexually transmitted infections. They are often asymptomatic, and therefore the patient is at risk of developing complications, such as pelvic inflammatory disease. It is important to recognize cervicitis, investigate it appropriately, and provide early treatment. Sexual partners must also be located and offered therapy to prevent re-infection in the index patient. PMID:21248969

  18. Radiation Therapy Plus Cisplatin and Gemcitabine in Treating Patients With Cervical Cancer

    ClinicalTrials.gov

    2014-12-23

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Small Cell Carcinoma; Cervical Squamous Cell Carcinoma; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  19. Experimental determination of Grunieisen gamma for two dissimilar materials (PEEK and Al 5083) via the shock-reverberation technique

    NASA Astrophysics Data System (ADS)

    Roberts, Andrew; Appleby-Thomas, Gareth; Hazell, Paul

    2011-06-01

    Following multiple loading events the resultant shock state of a material will lie away from the principle Hugoniot. Prediction of such states requires knowledge of a materials equation-of-state. The material-specific variable Grunieisen gamma (Γ) defines the shape of ``off-Hugoniot'' points in energy-volume-pressure space. Experimentally the shock-reverberation technique (based on the principle of impedance-matching) has previously allowed estimation of the first-order Grunieisen gamma term (Γ1) for a silicone elastomer. Here, this approach was employed to calculate Γ1 for two dissimilar materials, Polyether ether ketone (PEEK) and the armour-grade aluminium alloy 5083 (H32); thereby allowing discussion of limitations of this technique in the context of plate-impact experiments employing Manganin stress gauges. Finally, the experimentally determined values for Γ1 were further refined by comparison between experimental records and numerical simulations carried out using the commercial code ANYSYS Autodyn®.

  20. ACDF Using the Solis Cage with Iliac Bone Graft in Single Level: Clinical and Radiological Outcomes in Average 36 months Follow-up.

    PubMed

    Oh, Si-Hyuck; Yoon, Kyeong-Wook; Kim, Young-Jin; Lee, Sang-Koo

    2013-06-01

    To evaluate the utility of anterior cervical discectomy and fusion (ACDF) with polyetheretherketone (PEEK) cage and autograft through long term(average 36 months) follow-up. Thirty selected patients (male:20/female:10) who suffered from cervical radiculopathy, myelopathy or radiculomyelopathy underwent a single level ACDF with PEEK cage and autograft from iliac crest from March 2006 to July 2008 in single institute. We followed patients for an average 36.4±8.1 months (ranged from 23 to 49 months). The Japanese Orthopedic Association (JOA) score for evaluation of myelopathy and visual analogue scale (VAS) for radiating pain was used to estimate postoperative clinical outcome. Plain x-ray on true lateral standing flexion, extension and neutral position view and 3D CT scan were used every 6 months after surgery during follow-up period. The mean VAS and JOA scoring improved significantly after the surgery and radiological fusion rate was accomplished by 100% 36 months after the surgery. We had no complication related with the surgery except one case of osteomyelitis. There was one case of Grade I fusion, four cases of grade II, and 25 cases of grade III by radiologic evaluation. This long term follow-up study for ACDF with PEEK cage shows that this surgical method is comparable with other anterior cervical fusion methods in terms of clinical outcomes and radiologic fusion rate.

  1. ACDF Using the Solis Cage with Iliac Bone Graft in Single Level: Clinical and Radiological Outcomes in Average 36 months Follow-up

    PubMed Central

    Oh, Si-Hyuck; Yoon, Kyeong-wook; Lee, Sang-koo

    2013-01-01

    Objective To evaluate the utility of anterior cervical discectomy and fusion (ACDF) with polyetheretherketone (PEEK) cage and autograft through long term(average 36 months) follow-up. Methods Thirty selected patients (male:20/female:10) who suffered from cervical radiculopathy, myelopathy or radiculomyelopathy underwent a single level ACDF with PEEK cage and autograft from iliac crest from March 2006 to July 2008 in single institute. We followed patients for an average 36.4±8.1 months (ranged from 23 to 49 months). The Japanese Orthopedic Association (JOA) score for evaluation of myelopathy and visual analogue scale (VAS) for radiating pain was used to estimate postoperative clinical outcome. Plain x-ray on true lateral standing flexion, extension and neutral position view and 3D CT scan were used every 6 months after surgery during follow-up period. Results The mean VAS and JOA scoring improved significantly after the surgery and radiological fusion rate was accomplished by 100% 36 months after the surgery. We had no complication related with the surgery except one case of osteomyelitis. There was one case of Grade I fusion, four cases of grade II, and 25 cases of grade III by radiologic evaluation. Conclusion This long term follow-up study for ACDF with PEEK cage shows that this surgical method is comparable with other anterior cervical fusion methods in terms of clinical outcomes and radiologic fusion rate. PMID:24757462

  2. Severe cervical spondylotic myelopathy with complete neurological and neuroradiological recovery within a month after surgery

    PubMed Central

    Marios, Th.; Dimitrios, Zevgaridis; Theologos, Th.; Christos, Tsonidis

    2016-01-01

    Cervical spondylotic myelopathy is a complex syndrome evolving in the presence of degenerative changes. The choice of care and prognostic factors are controversial. The use of appropriate surgical technique is very important. Posterior approach may be chosen when pathology is present dorsally and/or in the presence of neutral to lordotic alignment. Anterior approach is the golden standard in patients with kyphosis and/or stenosis due to ventral lesions, even with three or more affected levels. A 67-year-old man presented with progressive weakness and clumsiness (mJOA: 5; Nurick: 4). An anterior discectomy, osteophytectomy and bilateral foraminotomy of the C4–C5; C5–C6; C6–C7 were performed. Polyether-Ether-Ketone spacers and a titanium plate were placed. The patient was mobilized 3-hour post-surgery and was released the following day. Medicament therapy and a neck-conditioning program were prescribed. Clinical examinations were normal within a month. Magnetic resonance imaging showed no traces of the preoperatively registered intramedullary focal T2 hyper-intensity. PMID:27887013

  3. Development and Validation of a Smartphone-Based Visual Acuity Test (Peek Acuity) for Clinical Practice and Community-Based Fieldwork.

    PubMed

    Bastawrous, Andrew; Rono, Hillary K; Livingstone, Iain A T; Weiss, Helen A; Jordan, Stewart; Kuper, Hannah; Burton, Matthew J

    2015-08-01

    Visual acuity is the most frequently performed measure of visual function in clinical practice and most people worldwide living with visual impairment are living in low- and middle-income countries. To design and validate a smartphone-based visual acuity test that is not dependent on familiarity with symbols or letters commonly used in the English language. Validation study conducted from December 11, 2013, to March 4, 2014, comparing results from smartphone-based Peek Acuity to Snellen acuity (clinical normal) charts and the Early Treatment Diabetic Retinopathy Study (ETDRS) logMAR chart (reference standard). This study was nested within the 6-year follow-up of the Nakuru Eye Disease Cohort in central Kenya and included 300 adults aged 55 years and older recruited consecutively. Outcome measures were monocular logMAR visual acuity scores for each test: ETDRS chart logMAR, Snellen acuity, and Peek Acuity. Peek Acuity was compared, in terms of test-retest variability and measurement time, with the Snellen acuity and ETDRS logMAR charts in participants' homes and temporary clinic settings in rural Kenya in 2013 and 2014. The 95% CI limits for test-retest variability of smartphone acuity data were ±0.033 logMAR. The mean differences between the smartphone-based test and the ETDRS chart and the smartphone-based test and Snellen acuity data were 0.07 (95% CI, 0.05-0.09) and 0.08 (95% CI, 0.06-0.10) logMAR, respectively, indicating that smartphone-based test acuities agreed well with those of the ETDRS and Snellen charts. The agreement of Peek Acuity and the ETDRS chart was greater than the Snellen chart with the ETDRS chart (95% CI, 0.05-0.10; P = .08). The local Kenyan community health care workers readily accepted the Peek Acuity smartphone test; it required minimal training and took no longer than the Snellen test (77 seconds vs 82 seconds; 95% CI, 71-84 seconds vs 73-91 seconds, respectively; P = .13). The study demonstrated that the Peek Acuity smartphone

  4. Arthrodesis Rate and Patient Reported Outcomes After Anterior Lumbar Interbody Fusion Utilizing a Plasma-Sprayed Titanium Coated PEEK Interbody Implant: A Retrospective, Observational Analysis

    PubMed Central

    Bergen, Sophea R.; Staples, Miranda; Liang, Kevin; Raiszadeh, Ramin

    2017-01-01

    Background Anterior lumbar interbody fusion (ALIF) is utilized in symptomatic spinal disc destabilization due to degenerative lumbar disc disease, isthmic and degenerative spondylolisthesis, internal disc disruption, or pseudarthrosis after non-operative treatments fail. The addition of a plasma-sprayed titanium coating (PTC) to polyether ether ketone spacers (PEEK) may reduce the rate of implant subsidence or non-union secondary to poor osseous-integration of non-coated PEEK or metal interbody systems. Methods A retrospective, non-randomized, single-center chart review, evaluated the post-surgical follow-up data of patients receiving a PTC PEEK implant during single or multi-level ALIF procedures to determine the clinical efficacy and rate of arthrodesis after utilization of a coated spacer. Standard roentgenographs or computed tomography were used to identify successful arthrodesis following the ALIF procedure and longitudinal clinical improvements were determined by scores on the Visual Analog Scale (VAS) for low back and leg pain. Results Forty-four subjects (48% male, mean=53 years) were included in this chart review. Follow-up radiology demonstrated radiographic union with bridging bone formation across the interbody space for 42/44 (96%) individuals with solid arthrodesis occurring at an average of 7.3 ± 2.3 months. Subjects demonstrated significant improvement in VAS low back pain (4.5 ± 2.4 point improvement, p=0.0001) and VAS leg pain (4.1 ± 3.3 point improvement, p=0.0001). While there was a significant reduction in the improvement of VAS low back pain of Worker's Compensation claimants as compared to other patients (3.9 ± 2.4 vs. 5.3 ± 2.1), there was no difference in VAS low back pain or leg pain when the data was stratified by gender, age, tobacco use, comorbidities, prior surgery, fusion construct length, use of supplemental posterior instrumentation, BMI, or diagnosis. Conclusions This study provides support that the addition of a PTC coating

  5. Graphene oxide as a dual-function conductive binder for PEEK-derived microporous carbons in high performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Kim, Christine H. J.; Zhang, Hongbo; Liu, Jie

    2015-06-01

    Microporous carbons (MPCs) are promising electrode materials for supercapacitors because of their high surface area and accessible pores. However, their low electrical conductivity and mechanical instability result in limited power density and poor cycle life. This work proposes a unique two-layered film made of polyetheretherketone-derived MPCs and reduced graphene oxide (rGO) as an electrode for supercapacitors. Electrochemical characterizations of films show that such a layered structure is more effective in increasing the accessibility of ions to the hydrophilic MPCs and establishing conductive paths through the rGO network than a simple mixed composite film. The two-layered structure increases the capacitance by ˜124% (237 F g-1) with excellent cycling stability (˜93% after 6000 cycles). More importantly, we demonstrate that such performance improvements result from an optimal balance between electrical conductivity and ion accessibility, which maximizes the synergistic effects of MPC and rGO. The MPCs, which are exposed to the surface, provide a highly accessible surface area for ion adsorption. The rGO serves a dual function as a conductive filler to increase the electrical conductivity and as a binder to interconnect individual MPC particles into a robust and flexible film. These findings provide a rational basis for the design of MPC-based electrodes in high performance supercapacitors.

  6. Investigation of metallic and carbon fibre PEEK fracture fixation devices for three-part proximal humeral fractures.

    PubMed

    Feerick, Emer M; Kennedy, Jim; Mullett, Hannan; FitzPatrick, David; McGarry, Patrick

    2013-06-01

    A computational investigation of proximal humeral fracture fixation has been conducted. Four devices were selected for the study; a locking plate, intramedullary nail (IM Nail), K-wires and a Bilboquet device. A 3D model of a humerus was created using a process of thresholding based on the grayscale values of a CT scan of an intact humerus. An idealised three part fracture was created in addition to removing a standard volume from the humeral head as a representation of bone voids that occur as a result of the injury. All finite element simulations conducted represent 90° arm abduction. Simulations were conducted to investigate the effect of filling this bone void with calcium phosphate cement for each device. The effect of constructing devices from carbon fibre polyetheretherketone (CFPEEK) was investigated. Simulations of cement reinforced devices predict greater stability for each device. The average unreinforced fracture line opening (FLO) is reduced by 48.5% for metallic devices with a lesser effect on composite devices with FLO reduced by 23.6%. Relative sliding (shear displacement) is also reduced between fracture fragments by an average of 58.34%. CFPEEK device simulations predict reduced stresses at the device-bone interface. Copyright © 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

  7. Cervical perineural cyst masquerading as a cervical spinal tumor.

    PubMed

    Joshi, Vijay P; Zanwar, Atul; Karande, Anuradha; Agrawal, Amit

    2014-04-01

    Tarlov (perineural) cysts of the nerve roots are common and usually incidental findings during magnetic resonance imaging of the lumbosacral spine. There are only a few case reports where cervical symptomatic perineural cysts have been described in the literature. We report such a case where a high cervical perineural cyst was masquerading as a cervical spinal tumor.

  8. Cervical Perineural Cyst Masquerading as a Cervical Spinal Tumor

    PubMed Central

    Joshi, Vijay P; Zanwar, Atul; Karande, Anuradha

    2014-01-01

    Tarlov (perineural) cysts of the nerve roots are common and usually incidental findings during magnetic resonance imaging of the lumbosacral spine. There are only a few case reports where cervical symptomatic perineural cysts have been described in the literature. We report such a case where a high cervical perineural cyst was masquerading as a cervical spinal tumor. PMID:24761204

  9. Spinal surgery -- cervical - series (image)

    MedlinePlus

    The cervical spinal column is made up of vertebral bodies which protect the spinal cord. ... spinal nerves, trauma, and narrowing (stenosis) of the spinal column around the spinal cord. Symptoms of cervical spine ...

  10. Cervical cancer -- screening and prevention

    MedlinePlus

    ... ency/patientinstructions/000419.htm Cervical cancer - screening and prevention To use the sharing features on this page, ... no visible warts or other symptoms. Vaccines to Prevent Cervical Cancer A vaccine is available to protect ...

  11. Cervical Spinal Motion During Intubation.

    DTIC Science & Technology

    2000-01-01

    Ten fresh human cadavers were intubated while recording cervical motion using a cinefluoroscopic technique. Segmental cervical motion from the...performed using no external stabilization, Gardner-Wells traction and manual in-line cervical immobilization. The data are currently being analyzed. A...paper entitled Segmental cervical spine motion during orotracheal intubation of the intact and injured spine with and without external stabilization was published in the Journal of Neurosurgery.

  12. Data Analysis in Cervical Trauma

    DTIC Science & Technology

    1989-04-01

    The cervical spine in lateral view is discussed and a method based on digital statistical analysis is used to reproduce quantitative data of the... cervical lordosis. (2) Marked straightening of the cervical spine. (3) Segmental straightening with reversal of the curve. Part II discusses the use of...the digital analysis to determine the displacement in subjects that have sustained ligamentous injuries of the cervical spine following whiplash injury.

  13. Cervical ectopic pregnancy.

    PubMed

    Samal, Sunil Kumar; Rathod, Setu

    2015-01-01

    Cervical pregnancy is a rare type of ectopic pregnancy and it represents <1% of all ectopic pregnancies. Early diagnosis and medical management with systemic or local administration of methotrexate is the treatment of choice. If the pregnancy is disturbed, it may lead to massive hemorrhage, which may require hysterectomy to save the patient. We report three cases of cervical pregnancy managed successfully with different approaches of management. Our first case, 28 years old G3P2L2 with previous two lower segment cesarean sections, presented with bleeding per vaginum following 6 weeks of amenorrhea. Clinical examination followed by transvaginal ultrasound confirmed the diagnosis of cervical pregnancy. Total abdominal hysterectomy was done in view of intractable bleeding to save the patient. The second case, a 26-year-old second gravida with previous normal vaginal delivery presented with pain abdomen and single episode of spotting per vaginum following 7 weeks of amenorrhea. Transvaginal ultrasound revealed empty endometrial cavity, closed internal os with gestational sac containing live fetus of 7 weeks gestational age in cervical canal and she was treated with intra-amniotic potassium chloride followed by systemic methotrexate. Follow up with serum beta human chorionic gonadotropin level revealed successful outcome. Our third case, a 27-year-old primigravida with history of infertility treatment admitted with complaints of bleeding per vaginum for 1 day following 8 weeks amenorrhea. She was diagnosed as cervical pregnancy by clinical examination, confirmed by transvaginal ultrasonography and subsequently managed by dilation and curettage with intracervical Foleys' ballon tamponade.

  14. Pilot study of a new acrylic cage in a dog cervical spine fusion model.

    PubMed

    Farrokhi, Majid Reza; Torabinezhad, Simin; Ghajar, Korush Azodi

    2010-06-01

    An experimental pilot study using an acrylic interbody cage in a dog cervical spine fusion model. To compare bony fusion in autologous bone grafting with a novel acrylic cage in terms of preservation of disc height, biomechanical properties, and histologic characteristics. Degenerative diseases of cervical intervertebral discs are commonly treated by anterior decompression and interbody fusion. To restore physiologic disc height and achieve fusion, the disc is replaced with bone graft, bone cement, interbody fusion cages, or other materials. The advantages of bone cement in contrast to bone graft and interbody fusion cages are immediate stability and less subsidence, although real bony fusion cannot be achieved. To overcome this problem, we designed a new, inexpensive acrylic cage. Ten adult hybrid dogs underwent C3/C4 (5 dogs) and C4/C5 (5 dogs) discectomy and fusion with an acrylic interbody fusion cage made of polymethylmethacrylate filled with bone graft (n=5, group1) or an autologous iliac bone graft (n=5, group 2). Dynamic functional x-ray was obtained 1 and 12 weeks after the operation. After 12 weeks, the animals were killed and fusion sites were evaluated with quantitative computed tomographic scanning to evaluate bone mineral density. Subsistence was quantified with biomechanical testing. Histopathologic analysis was used to evaluate fusion and possible foreign body reactions associated with the acrylic cage. The acrylic cage led to significantly higher disc space height and less subsidence than bone grafting (P<0.021). Bone mineral density after 12 weeks was greater with the acrylic cage, but the difference was not statistically significant. Histologically, new bony tissue and hyaline cartilage were seen inside the acrylic cage, accompanied by mild chronic inflammation. The acrylic cage showed significantly higher mechanical stiffness and less subsidence than bone grafting. Additional studies with more subjects and longer follow-up periods are needed to

  15. Cervical Total Disc Arthroplasty

    PubMed Central

    Basho, Rahul; Hood, Kenneth A.

    2012-01-01

    Symptomatic adjacent segment degeneration of the cervical spine remains problematic for patients and surgeons alike. Despite advances in surgical techniques and instrumentation, the solution remains elusive. Spurred by the success of total joint arthroplasty in hips and knees, surgeons and industry have turned to motion preservation devices in the cervical spine. By preserving motion at the diseased level, the hope is that adjacent segment degeneration can be prevented. Multiple cervical disc arthroplasty devices have come onto the market and completed Food and Drug Administration Investigational Device Exemption trials. Though some of the early results demonstrate equivalency of arthroplasty to fusion, compelling evidence of benefits in terms of symptomatic adjacent segment degeneration are lacking. In addition, non-industry-sponsored studies indicate that these devices are equivalent to fusion in terms of adjacent segment degeneration. Longer-term studies will eventually provide the definitive answer. PMID:24353955

  16. Investigation of the peeks creek debris flow of September 2004 and its relationship to landslide hazard mapping in Macon County, North Carolina

    Treesearch

    Rebecca Latham; Rick Wooten; Anne Witt; Ken Gillon; Tommy Douglas; Stephen Fuemmeler; Jennifer Bauer; Scott Brame

    2007-01-01

    On September 16,2004 the remnants of Hurricane Ivan dumped heavy rain on Macon County, North Carolina, triggering a debris slide near the top of Fishhawk Mountain (figure 1) at an elevation of 4,420 ft around 10: 10 PM. This slide quickly mobilized into a debris flow that traveled approximately 2.25 miles and dropped 2,000 ft colliding with the Peeks Creek community...

  17. Porous poly-ether ether ketone (PEEK) manufactured by a novel powder route using near-spherical salt bead porogens: characterisation and mechanical properties.

    PubMed

    Siddiq, Abdur R; Kennedy, Andrew R

    2015-02-01

    Porous PEEK structures with approximately 85% open porosity have been made using PEEK-OPTIMA® powder and a particulate leaching technique using porous, near-spherical, sodium chloride beads. A novel manufacturing approach is presented and compared with a traditional dry mixing method. Irrespective of the method used, the use of near-spherical beads with a fairly narrow size range results in uniform pore structures. However the integration, by tapping, of fine PEEK into a pre-existing network salt beads, followed by compaction and "sintering", produces porous structures with excellent repeatability and homogeneity of density; more uniform pore and strut sizes; an improved and predictable level of connectivity via the formation of "windows" between the cells; faster salt removal rates and lower levels of residual salt. Although tapped samples show a compressive yield stress >1 MPa and stiffness >30 MPa for samples with 84% porosity, the presence of windows in the cell walls means that tapped structures show lower strengths and lower stiffnesses than equivalent structures made by mixing.

  18. PEEK tube-based online solid-phase microextraction-high-performance liquid chromatography for the determination of yohimbine in rat plasma and its application in pharmacokinetics study.

    PubMed

    Xiang, Xiaowei; Shang, Bing; Wang, Xiaozheng; Chen, Qinhua

    2017-04-01

    Yohimbine is a novel compound for the treatment of erectile dysfunction derived from natural products, and pharmacokinetic study is important for its further development as a new medicine. In this work, we developed a novel PEEK tube-based solid-phase microextraction (SPME)-HPLC method for analysis of yohimbine in plasma and further for pharmacokinetic study. Poly (AA-EGDMA) was synthesized inside a PEEK tube as the sorbent for microextraction of yohimbine, and parameters that could influence extraction efficiency were systematically investigated. Under optimum conditions, the PEEK tube-based SPME method exhibits excellent enrichment efficiency towards yohimbine. By using berberine as internal standard, an online SPME-HPLC method was developed for analysis of yohimbine in human plasma sample. The method has wide linear range (2-1000 ng/mL) with an R(2) of 0.9962; the limit of detection was determined and was as low as 0.1 ng/mL using UV detection. Finally, a pharmacokinetic study of yohimbine was carried out by the online SPME-HPLC method and the results have been compared with those of reported methods.

  19. Amniotic membrane for cervical reconstruction.

    PubMed

    Mhaskar, R

    2005-08-01

    To evaluate the use of amniotic membrane grafts in cases of vaginal and cervical agenesis. Five girls with complete cervical and vaginal agenesis underwent cervicoplasty and vaginoplasty using amniotic membrane grafts. Excellent epithelization and patency of cervix and vagina was achieved in all cases. Amniotic membrane may be used as an allograft in cervical reconstruction. It is inexpensive, readily available, of low antigenicity and does not necessitate repeated cervical dilatation. The performance of the reconstructed cervix during labor is yet to be observed. To the author's knowledge, this is the first series reported in the literature in which amniotic membrane was used for cervical reconstruction.

  20. Cisplatin and Radiation Therapy With or Without Tirapazamine in Treating Patients With Cervical Cancer

    ClinicalTrials.gov

    2014-06-18

    Cervical Adenocarcinoma; Cervical Adenosquamous Cell Carcinoma; Cervical Squamous Cell Carcinoma; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  1. Cervical spine trauma

    PubMed Central

    Torretti, Joel A; Sengupta, Dilip K

    2007-01-01

    Cervical spine trauma is a common problem with a wide range of severity from minor ligamentous injury to frank osteo-ligamentous instability with spinal cord injury. The emergent evaluation of patients at risk relies on standardized clinical and radiographic protocols to identify injuries; elucidate associated pathology; classify injuries; and predict instability, treatment and outcomes. The unique anatomy of each region of the cervical spine demands a review of each segment individually. This article examines both upper cervical spine injuries, as well as subaxial spine trauma. The purpose of this article is to provide a review of the broad topic of cervical spine trauma with reference to the classic literature, as well as to summarize all recently available literature on each topic. Identification of References for Inclusion: A Pubmed and Ovid search was performed for each topic in the review to identify recently published articles relevant to the review. In addition prior reviews and classic references were evaluated individually for inclusion of classic papers, classifications and previously unidentified references. PMID:21139776

  2. Cervical Neoplasia Probe Control

    SciTech Connect

    Vargo, Timothy D.

    1997-01-24

    This software, which consists of a main executive and several subroutines, performs control of the optics, image acquisition, and Digital Signal Processing (DSP) of this image, of an optical based medical instrument that performs fluoresence detection of precancerous lesions (neoplasia) of the human cervix. The hardware portion of this medical instrument is known by the same name Cervical Neoplasia Probe (CNP)

  3. Cervical ectopic pregnancy

    PubMed Central

    Samal, Sunil Kumar; Rathod, Setu

    2015-01-01

    Cervical pregnancy is a rare type of ectopic pregnancy and it represents <1% of all ectopic pregnancies. Early diagnosis and medical management with systemic or local administration of methotrexate is the treatment of choice. If the pregnancy is disturbed, it may lead to massive hemorrhage, which may require hysterectomy to save the patient. We report three cases of cervical pregnancy managed successfully with different approaches of management. Our first case, 28 years old G3P2L2 with previous two lower segment cesarean sections, presented with bleeding per vaginum following 6 weeks of amenorrhea. Clinical examination followed by transvaginal ultrasound confirmed the diagnosis of cervical pregnancy. Total abdominal hysterectomy was done in view of intractable bleeding to save the patient. The second case, a 26-year-old second gravida with previous normal vaginal delivery presented with pain abdomen and single episode of spotting per vaginum following 7 weeks of amenorrhea. Transvaginal ultrasound revealed empty endometrial cavity, closed internal os with gestational sac containing live fetus of 7 weeks gestational age in cervical canal and she was treated with intra-amniotic potassium chloride followed by systemic methotrexate. Follow up with serum beta human chorionic gonadotropin level revealed successful outcome. Our third case, a 27-year-old primigravida with history of infertility treatment admitted with complaints of bleeding per vaginum for 1 day following 8 weeks amenorrhea. She was diagnosed as cervical pregnancy by clinical examination, confirmed by transvaginal ultrasonography and subsequently managed by dilation and curettage with intracervical Foleys’ ballon tamponade. PMID:25810679

  4. Postcoital bleeding due to cervical endometriosis

    PubMed Central

    Seval, Mehmet Murat; Cavkaytar, Sabri; Atak, Zeliha; Guresci, Servet

    2013-01-01

    Endometriosis of the uterine cervix is a rare lesion that is generally asymptomatic in gynaecological practice. We present a case with postcoital bleeding due to a cervical mass mimicking cervical polyp or fibroma which was histologically proven as cervical endometriosis later. Cervical endometriosis should be considered in the differential diagnosis of cervical masses with postcoital bleeding. PMID:23376669

  5. Postcoital bleeding due to cervical endometriosis.

    PubMed

    Seval, Mehmet Murat; Cavkaytar, Sabri; Atak, Zeliha; Guresci, Servet

    2013-01-31

    Endometriosis of the uterine cervix is a rare lesion that is generally asymptomatic in gynaecological practice. We present a case with postcoital bleeding due to a cervical mass mimicking cervical polyp or fibroma which was histologically proven as cervical endometriosis later. Cervical endometriosis should be considered in the differential diagnosis of cervical masses with postcoital bleeding.

  6. Mechanical assessment of a hip joint stem model made of a PEEK/carbon fibre composite under compression loading.

    PubMed

    Dworak, Michał; Błażewicz, Stanisław

    2016-01-01

    The aim of the work was to manufacture a composite stem model consisting of carbon fibres (CF) and polyether ether ketone (PEEK) and to perform the surface strain and stress distributions in the stem-femoral bone model under compression loading. Composite stems differing in elasticity were prepared. Three types of composite stems having different arrangements of carbon fibre reinforcements (carbon fibre roving, carbon fibre sleeves and their combinations) in the polymer matrix were made. The stems were cementless fixed in the femoral bone model channel or with the use of the polymer bone cement (PMMA). Mechanical behaviour of composite stems under compression loading was compared with a metallic stem by strain gauge measurements at different parts of stem/bone model systems. The values of stresses in the proximal part of the bone model for cemented and cementless fixations of the composite stem in the femoral bone channel were higher than those noted for the metallic stem. The increase in proximal bone stress was almost similar for both types of fixation of composite stems, i.e., cemented and cementless fixed stems. The optimal range of mechanical stiffness, strengths and work up to fracture was obtained for composite stem made of carbon fibre sleeves and carbon fibres in the form of roving. Depending on the elasticity of the composite stem model, an increase in the stress in the proximal part of femoral bone model of up to 40% was achieved in comparison with the metallic stem.

  7. The influence of a compatibilizer on the thermal and dynamic mechanical properties of PEEK/carbon nanotube composites.

    PubMed

    Díez-Pascual, A M; Naffakh, M; Gómez, M A; Marco, C; Ellis, G; González-Domínguez, J M; Ansón, A; Martínez, M T; Martínez-Rubi, Y; Simard, B; Ashrafi, B

    2009-08-05

    The effect of polyetherimide (PEI) as a compatibilizing agent on the morphology, thermal, electrical and dynamic mechanical properties of poly(ether ether ketone) (PEEK)/single-walled carbon nanotube (SWCNT) nanocomposites, has been investigated for different CNT loadings. After a pre-processing step based on ball milling and pre-mixing under mechanical treatment in ethanol, the samples were prepared by melt extrusion. A more homogeneous distribution of the CNTs throughout the matrix is found for composites containing PEI, as revealed by scanning electron microscopy. Thermogravimetric analysis demonstrates an increase in the matrix degradation temperatures under dry air and nitrogen atmospheres with the addition of SWCNTs; the level of thermal stability of these nanocomposites is maintained when PEI is incorporated. Both differential scanning calorimetry and synchrotron x-ray scattering studies indicate a slight decrease in the crystallization temperatures of the compatibilized samples, and suggest the existence of reorganization phenomena during the heating, which are favoured in the composites incorporating the compatibilizer, due to their smaller crystal size. Dynamic mechanical studies show an increase in the glass transition temperature of the nanocomposites upon the addition of PEI. Furthermore, the presence of PEI causes an enhancement in the storage modulus, and hence in the rigidity of these systems, attributed to an improved interfacial adhesion between the reinforcement and the matrix. The electrical and thermal conductivities of these composites decrease with the incorporation of PEI. Overall, the compatibilized samples exhibit improved properties and are promising for their use in industrial applications.

  8. Water absorption in PEEK and PEI matrices. Contribution to the understanding of water-polar group interactions

    NASA Astrophysics Data System (ADS)

    Courvoisier, E.; Bicaba, Y.; Colin, X.

    2016-05-01

    The water absorption in two aromatic linear polymers (PEEK and PEI) was studied between 10% and 90% RH at 30, 50 and 70°C. It was found that these polymers display classical Henry and Fick's behaviors. Moreover, they have very close values of equilibrium water concentration C∞ and water diffusivity D presumably because their respective polar groups establish molecular interactions of the same nature with water. This assumption was checked from a literature compilation of values of C∞ and D for a large variety of linear and tridimensional polymers containing a single type of polar group. It was then evidenced that almost all types of carbonyl group (in particular, those belonging to imides, amides and ketones) have the same molar contribution to water absorption, except those belonging to esters which are much less hydrophilic. Furthermore, hydroxyl and sulfone groups are much more hydrophilic than carbonyl groups so that their molar contribution is located on another master curve. On this basis, semi-empirical structure/water transport property relationships were proposed. It was found that C∞ increases exponentially with the concentration of polar groups (presumably because water is doubly bonded), but also with the intensity of their molecular interactions with water. In contrast, D is inversely proportional to C∞, which means that polar group-water interactions slow down the rate of water diffusion.

  9. Leprotic cervical spondylodiscitis

    PubMed Central

    Lee, Tae Hoon; Shin, Jun Jae; Chae, Gue Tae

    2010-01-01

    Leprosy is a chronic infectious disease caused by the Mycobacterium leprae that leads to leprotic neuropathy involving the peripheral nerve and several characteristic skin lesions. Skeletal involvement can occur in peripheral joints, such as the wrist and the ankle. However, there is no report of an axial leprotic lesion involving the spine or paraspinal soft tissue. The authors report the first case of a leprotic cervical lesion involving the axial skeletal system. A 48-year-old male presented with neck pain and severe pain in the right suprascapular area and left arm. Preoperative MRI of the cervical spine revealed signal changes in the prevertebral soft tissue at the level of the C3, 4, 5 vertebral bodies. There were a lower signal intensity on T1-weighted image and high signal intensity on T2WI of the bone marrow at the level of the C5 and C6 vertebral bodies, and a C5/6 segmental ossification of the posterior longitudinal ligament. There were herniated cervical disc on the left C5/6 with C6 root and the right side of C6/7 with a C7 root compression. He was previously diagnosed with leprosy when he was 14 years old and received treatment intermittently over the course of 7 years. But patient did not disclose his past history. Surgical intervention was conducted using an anterior cervical approach. An incision was made in the anterior longitudinal ligament at C5/6, and a pinkish gray friable gelatinous material was observed on the C5/6 disc and on the anterior lower one-third surface of the C5 vertebral body. Specimens were obtained and subjected to pathological evaluation and microbiological culture. After C5/6 and C6/7 discectomies, nerve root decompression and autologous iliac bone grafting were performed at the C5/6 and C6/7 levels. The C5–6–7 vertebrae were fixed with an Atlantis® cervical locking plate and a screw system. The pathological report indicated chronic inflammation with heavy plasma cell infiltration on the specimen. We sent the specimens

  10. Cervical spine reposition errors after cervical flexion and extension.

    PubMed

    Wang, Xu; Lindstroem, René; Carstens, Niels Peter Bak; Graven-Nielsen, Thomas

    2017-03-13

    Upright head and neck position has been frequently applied as baseline for diagnosis of neck problems. However, the variance of the position after cervical motions has never been demonstrated. Thus, it is unclear if the baseline position varies evenly across the cervical joints. The purpose was to assess reposition errors of upright cervical spine. Cervical reposition errors were measured in twenty healthy subjects (6 females) using video-fluoroscopy. Two flexion movements were performed with a 20 s interval, the same was repeated for extension, with an interval of 5 min between flexion and extension movements. Cervical joint positions were assessed with anatomical landmarks and external markers in a Matlab program. Reposition errors were extracted in degrees (initial position minus reposition) as constant errors (CEs) and absolute errors (AEs). Twelve of twenty-eight CEs (7 joints times 4 repositions) exceeded the minimal detectable change (MDC), while all AEs exceeded the MDC. Averaged AEs across the cervical joints were larger after 5 min' intervals compared to 20 s intervals (p < 0.05). This is the first study to demonstrate single joint reposition errors of the cervical spine. The cervical spine returns to the upright positions with a 2° average absolute difference after cervical flexion and extension movements in healthy adults.

  11. Cetuximab, Cisplatin, and Radiation Therapy in Treating Patients With Stage IB, Stage II, Stage III, or Stage IVA Cervical Cancer

    ClinicalTrials.gov

    2014-12-29

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Small Cell Carcinoma; Cervical Squamous Cell Carcinoma; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  12. Cisplatin and Radiation Therapy Followed by Paclitaxel and Carboplatin in Treating Patients With Stage IB-IVA Cervical Cancer

    ClinicalTrials.gov

    2017-05-03

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma, Not Otherwise Specified; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage IIIA Cervical Cancer; Stage IIIB Cervical Cancer; Stage IVA Cervical Cancer

  13. Comparison of 3 fusion techniques in the treatment of the degenerative cervical spine disease. Is stand-alone autograft really the "gold standard?": prospective study with 2-year follow-up.

    PubMed

    Vanek, Petr; Bradac, Ondrej; DeLacy, Patricia; Saur, Karel; Belsan, Tomas; Benes, Vladimir

    2012-09-01

    A prospective study. The aim of this study was to compare the 3 different methods of interbody fusion of the cervical spine-autograft in stand-alone technique, autograft with anterior plate, and polyetheretherketone cage supported by anterior plate. The clinical and radiological data obtained were analyzed and discussed. Although degenerative cervical spine disease has been treated by an anterior approach for more than 50 years, there is not one generally accepted operative approach. There is a very low-quality evidence of little or no difference in pain relief between each of the techniques. Iliac crest autograft still seems to be the "gold standard" for interbody fusion. Prospective study collecting clinical and radiological data of 81 patients undergoing anterior cervical interbody fusion, in which the interbody fusion of 1 or 2 motion segments from C3 to C7 was done by any of the 3 techniques--stand-alone insertion of autograft (group 1: 28 patients), autograft and anterior plate (group 2: 18 patients), and polyetheretherketone cage filled with beta-tricalcium phosphate and plate (group 3: 29 patients). Patients were followed for 2 years after surgery. Significant interaction of relative height in the segment and time was found (P < 0.001). The values of the relative height of stand-alone autograft dropped below 95% of initial height and the values of the other 2 groups remained above 105%. Significant interaction of time and group was found for Cobb S angles (P < 0.001). Values of group 1 decreased substantially and remained significantly lower than values of other 2 groups. Fusion rate was 100% in all groups. Neck Disability Index group and time interaction was found (P = 0.023). During postoperative follow-up, group 1 scored in all controls higher than the other 2 groups, but differences were not significant. Visual analogue scale showed effect of time (P < 0.001). This was due to a smaller improvement of patients in group 1 during the whole follow-up in

  14. Os Odontoideum: Rare Cervical Lesion

    DTIC Science & Technology

    2011-11-01

    the articulation between C1 and the os odontoideum on flexion imaging. The remainder of his cervical vertebral bodies had normal alignment with no...appears normal. Figure 3. Flexion view of plain cervical spine. This image shows abnormal translation of the articulation between C1 and the C2 os...worldwide. Peer Reviewed Title: Os Odontoideum: Rare Cervical Lesion Journal Issue: Western Journal of Emergency Medicine, 12(4) Author: Robson

  15. Chronic Pseudomonas aeruginosa cervical osteomyelitis

    PubMed Central

    Meher, Sujeet Kumar; Jain, Harsh; Tripathy, Laxmi Narayan; Basu, Sunandan

    2016-01-01

    Pseudomonas aeruginosa is a rare cause of osteomyelitis of the cervical spine and is usually seen in the background of intravenous drug use and immunocompromised state. Very few cases of osteomyelitis of the cervical spine caused by pseudomonas aeruginosa have been reported in otherwise healthy patients. This is a case presentation of a young female, who in the absence of known risk factors for cervical osteomyelitis presented with progressively worsening neurological signs and symptoms. PMID:27891039

  16. [Primary cervical cancer screening].

    PubMed

    Vargas-Hernández, Víctor Manuel; Vargas-Aguilar, Víctor Manuel; Tovar-Rodríguez, José María

    2015-01-01

    Cervico-uterine cancer screening with cytology decrease incidence by more than 50%. The cause of this cancer is the human papilloma virus high risk, and requires a sensitive test to provide sufficient sensitivity and specificity for early detection and greater interval period when the results are negative. The test of the human papilloma virus high risk, is effective and safe because of its excellent sensitivity, negative predictive value and optimal reproducibility, especially when combined with liquid-based cytology or biomarkers with viral load, with higher sensitivity and specificity, by reducing false positives for the detection of cervical intraepithelial neoplasia grade 2 or greater injury, with excellent clinical benefits to cervical cancer screening and related infection of human papilloma virus diseases, is currently the best test for early detection infection of human papillomavirus and the risk of carcinogenesis.

  17. Cervical plate fracture: a rare complication

    PubMed Central

    Veli, Citisli; Muhammet, Ibrahimoglu; Serkan, Civlan; Murat, Kocaoglu

    2015-01-01

    In traumatic and degenerative diseases cervical fusion with anterior cervical plate are commonly used. The increase in the use of cervical plate segment level is also increased risk of developing complications. This case report shows that the increase in the use of cervical plate segment level and also the complications in cervical spinal instrumentation, short-segment cervical plate rare case reported to be broken. PMID:26161189

  18. Cervical plate fracture: a rare complication.

    PubMed

    Veli, Citisli; Muhammet, Ibrahimoglu; Serkan, Civlan; Murat, Kocaoglu

    2015-01-01

    In traumatic and degenerative diseases cervical fusion with anterior cervical plate are commonly used. The increase in the use of cervical plate segment level is also increased risk of developing complications. This case report shows that the increase in the use of cervical plate segment level and also the complications in cervical spinal instrumentation, short-segment cervical plate rare case reported to be broken.

  19. [Measurement and clinical significance of cervical lordosis].

    PubMed

    Zhang, Yu-ting; Wang, Xiang; Zhan, Hong-sheng

    2014-12-01

    Measurement of cervical lordosis is the basic method for evaluating cervical function, and important reference for determine treatment decision. However, how to choose appropriate measurement in accordance with different situation, as well as the relationship among these methods is not clear. An increasing number of studies suggested that different measurements could directly affect the judgment of cervical lordosis. Therefore, comparative study of cervical vertebrae plays an important role in clinical treatment for cervical spondylosis under different cervical curvature conditions.

  20. Achondroplasia and cervical laminoplasty.

    PubMed

    Yoshii, June; Traynelis, Vincent C

    2009-10-01

    Achondroplasia is associated with short pedicles that predispose individuals with this trait to develop symptomatic spinal canal stenosis. Laminoplasty is an excellent means of treating cervical myelopathy due to stenosis in selected individuals. Laminoplasty preserves segmental motion and stability, both of which are of benefit to all individuals. The authors report the successful surgical treatment of an achondroplastic adult woman with laminoplasty. This procedure alleviated her symptoms, and she was doing well at 2-year follow-up.

  1. Cervical split: A pseudofracture

    SciTech Connect

    Goldberg, R.P.; Vine, H.S.; Sacks, B.A.; Ellison, H.P.

    1982-01-01

    A horizontal lucent line projecting over a cervical vertebral body on lateral radiographs and simulating a fracture is described. This pseudofracture line results from the lucency between contiguous proliferative osteophytes at the uncinate process/vertebral articulation. Associated disc space narrowing was seen in all of our eleven cases. The origin of this pseudofracture line, cases illustrating this phenomenon, and additional projections helpful for clarification are presented.

  2. Congenital midline cervical cleft.

    PubMed

    Agag, Richard; Sacks, Justin; Silver, Lester

    2007-01-01

    Congenital midline cervical cleft (CMCC) is a rare disorder of the ventral neck that is clinically evident at birth and must be differentiated from the more common thyroglossal duct cyst. The case of CMCC presented here was associated with chromosomes 13/14 de novo Robertsonian translocations as well as midline deformities including a sacral tuft and a minor tongue-tie. The case is presented as well as discussion of histopathology, embryology, and surgical treatment.

  3. Preinduction cervical ripening.

    PubMed

    Thiery, M

    1983-01-01

    This work reviews the evolution of cervical ripening procedures and discusses the most effective current techniques. Current knowledge of the process of spontaneous ripening of the cervix is briefly assessed, but the review concentrates on methodological aspects and the clinical results of preinduction cervical ripening. The historical development of mechanical and pharmacologic ripening procedures is examined, including enzymes, oxytocin, relaxin, corticosteriods, estrogens administered parenterally or locally, and prostaglandins (PGs) administered intravenously, orally, locally, and intravaginally. 3 effective procedures for preinduction cervical ripening are identified and described in greater detail: the catheter technique and local and vaginal administration of PGs. The extraamniotic catheter technique is simple, effective, and safe and is recommended for patients with not totally unripe cervixes and for whom PGs are unavailable or contraindicated. Single-dose extraamniotic instillation of PGE2 in Tylose gel was found to be highly effective for priming the unfavorable cervix before conventional labor induction. In some patients the procedure induces labor. The technique is easy to use, well accepted by the woman, and safe when applied appropriately to carefully selected patients. PGF2alpha gel has been less thoroughly studied. Electronic monitoring at the ripening stage is recommended for patients at risk, and even in low-risk cases much larger series will require study before conclusions can be reached about safety. Injection of PG gel into the cervical canal is less invasive than extraamniotic instillation, but no definite conclusions about its safety are possible due to small series and dissimilar clinical protocols. Pericervical administration of PGE2 and PGF2 alpha and intracervical and intraamniotic tablets of PGE2 are briefly assessed. Adoption of the intravaginal route has been a major step in the development of ripening techniques. 3 types of media

  4. Osteotomies in the Cervical Spine

    PubMed Central

    Nemani, Venu M.; Derman, Peter B.

    2016-01-01

    Rigid cervical deformities are difficult problems to treat. The goals of surgical treatment include deformity correction, achieving a rigid fusion, and performing a thorough neural decompression. In stiff and ankylosed cervical spines, osteotomies are required to restore sagittal and coronal balance. In this chapter, we describe the clinical and radiographic workup for patients with cervical deformities, and delineate the various factors that must be considered when planning surgical treatment. We also describe in detail the various types of cervical osteotomies, along with their surgical technique, advantages, and potential complications. PMID:26949476

  5. Hybrid cervical disc arthroplasty.

    PubMed

    Tu, Tsung-Hsi; Wu, Jau-Ching; Cheng, Henrich; Mummaneni, Praveen V

    2017-01-01

    For patients with multilevel cervical stenosis at nonadjacent segments, one of the traditional approaches has included a multilevel fusion of the abnormal segments as well as the intervening normal segment. In this video we demonstrate an alternative treatment plan with tailored use of a combination of anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) with an intervening skipped level. The authors present the case of a 72-year-old woman with myeloradiculopathy and a large disc herniation with facet joint degeneration at C3-4 and bulging disc at C5-6. After nonoperative treatment failed, she underwent a single-level ACDF at C3-4 and single-level arthroplasty at C5-6, which successfully relieved her symptoms. No intervention was performed at the normal intervening C4-5 segment. By using ACDF combined with arthroplasty, the authors have avoided a 3-level fusion for this patient and maintained the range of motion of 2 disc levels. The video can be found here: https://youtu.be/OrxcPUBvqLk .

  6. The degenerative cervical spine.

    PubMed

    Llopis, E; Belloch, E; León, J P; Higueras, V; Piquer, J

    2016-04-01

    Imaging techniques provide excellent anatomical images of the cervical spine. The choice to use one technique or another will depend on the clinical scenario and on the treatment options. Plain-film X-rays continue to be fundamental, because they make it possible to evaluate the alignment and bone changes; they are also useful for follow-up after treatment. The better contrast resolution provided by magnetic resonance imaging makes it possible to evaluate the soft tissues, including the intervertebral discs, ligaments, bone marrow, and spinal cord. The role of computed tomography in the study of degenerative disease has changed in recent years owing to its great spatial resolution and its capacity to depict osseous components. In this article, we will review the anatomy and biomechanical characteristics of the cervical spine, and then we provide a more detailed discussion of the degenerative diseases that can affect the cervical spine and their clinical management. Copyright © 2015 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  7. [Cervical spine trauma].

    PubMed

    Yilmaz, U; Hellen, P

    2016-08-01

    In the emergency department 65 % of spinal injuries and 2-5 % of blunt force injuries involve the cervical spine. Of these injuries approximately 50 % involve C5 and/or C6 and 30 % involve C2. Older patients tend to have higher spinal injuries and younger patients tend to have lower injuries. The anatomical and development-related characteristics of the pediatric spine as well as degenerative and comorbid pathological changes of the spine in the elderly can make the radiological evaluation of spinal injuries difficult with respect to possible trauma sequelae in young and old patients. Two different North American studies have investigated clinical criteria to rule out cervical spine injuries with sufficient certainty and without using imaging. Imaging of cervical trauma should be performed when injuries cannot be clinically excluded according to evidence-based criteria. Degenerative changes and anatomical differences have to be taken into account in the evaluation of imaging of elderly and pediatric patients.

  8. Radiation Therapy and Cisplatin With or Without Epoetin Alfa in Treating Patients With Cervical Cancer and Anemia

    ClinicalTrials.gov

    2014-12-29

    Anemia; Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma; Drug Toxicity; Radiation Toxicity; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  9. Cervical Cancer Working Group report.

    PubMed

    Konno, Ryo; Sagae, Satoru; Yoshikawa, Hiroyuki; Basu, Partha Sarathi; Hanley, Sharon J B; Tan, Jeffrey H J; Shin, Hai-Rim

    2010-09-01

    Disease burden of cervical cancer in Asia was summarized. Human papillomavirus 16 is the most oncogenic human papillomavirus type. Korea's national cervical cancer screening program targets women aged 30 or over, with coverage of almost 80%. Japan has a long history (50 years) of cervical cancer screening, and cytological screening programs have reduced the incidence/mortality of cervical cancer by 70%. But, recent cervical cancer screening coverage is ∼24%. Modeling suggested that vaccination of all 12-year-old girls would reduce cervical cancer cases by 73% in Japan. India has no cervical cancer screening program, as well as a serious lack of awareness in the general population, medical professionals and policy-makers. A realistic, affordable approach would be a low-volume, once-in-a-lifetime human papillomavirus-based screening program. In Australia, the national cervical cancer program has been very successful in reducing the incidence and mortality of cervical cancer. Australia was the first country to implement free, national human papillomavirus immunization (April 2007), expected to reduce human papillomavirus 16 infections by 56% in 2010 and 92% in 2050. A comparison of the UK and Japan was demonstrated that in the UK, cervical cancer screening and human papillomavirus vaccination uptakes are high because the government provides adequate education/funding. The Japanese government needs to put more emphasis on women's health and preventative medicine. Our conclusion and recommendations are that heightened public awareness of cervical cancer prevention, focusing on screening and vaccination will lead to improved survival and a better quality of life.

  10. Characterization of impact damage resistance of CF/PEEK and CF/toughened epoxy laminates under low and high velocity impact tests

    SciTech Connect

    Morita, Hideo; Adachi, Tadaharu; Tateishi, Yasuhiro; Matsumoto, Hiroyuki

    1995-12-31

    In order to use composite materials in aeronautical turbo engines, their resistance to impact damage must be understood. In this work the subperforation flat-wise impact resistance of three kinds of high resistance material systems were evaluated under low and high velocity impact tests. Tested systems were AS4/PEEK (APC-2/AS4, ICI-Fiberite), AS4/PEEK+IL, which consists of APC-2 prepreg and PEEK film inserted between layers as an interleave, and toughened epoxy system T800/{number_sign}3900 (Toray). To investigate the effects of stacking sequence on resistance, three lay-ups -- (0/+30/0/{minus}30)s, (0/+60/0/{minus}60)s, and (0/+45/90/{minus}45)s -- were tested. A drop weight system was used for the low velocity tests, where the velocity ranged from 1.5 to 3.1 m/s. An air gun system was used for the high velocity tests, where the velocity range was between 50 and 100 m/s. The relation between damage area (DA) and impact energy (IE) was linear, and the ratio of the DA/IE quantified the impact resistance of each specimen. The value of DA/IE for the high velocity tests was larger than the value for low velocity tests. To estimate the lay-up effect, a stacking parameter {beta}, which indicates the difference of the inplane stiffness between the adjacent laminae, was proposed. A proportional relation between the DA/IE and the {beta} was obtained. The value of (DA/IE)/{beta}, which was independent of stacking sequence, indicated the impact resistance of the tested material systems for both velocity levels. The ratio of (DA/IE)/{beta} for the high velocity to the value for the low velocity changed with material systems.

  11. Surgical Outcomes of Anterior Cervical Fusion Using Deminaralized Bone Matrix as Stand-Alone Graft Material: Single Arm, Pilot Study.

    PubMed

    Chung, Ho-Jung; Hur, Jung-Woo; Ryu, Kyeong-Sik; Kim, Jin-Sung; Seong, Ji-Hoon

    2016-09-01

    To investigate the safety and efficacy of demineralized bone matrix (DBM) as a bone graft substitute for anterior cervical discectomy and fusion (ACDF) surgery. Twenty consecutive patients treated with ACDF using stand-alone polyestheretherketone (PEEK) cages (Zero-P) with DBM(CGDBM100) were prospectively evaluated with a minimum of 6 months of follow-up. Radiologic efficacy was evaluated with a 6-point scoring method for osseous fusion using plain radiograph and computed tomogrpahy scans. Clinical efficacy was evaluated using the visual analogue scale (VAS), Owestry disability index (ODI), and short-form health questionnaire-36. The safety of the bone graft substitute was assessed with vital sign monitoring and a survey measuring complications at each follow-up visit. There were significant improvements in VAS and ODI scores at a mean 6-month follow-up. Six months after surgery, solid fusion was achieved in all patients. Mean score on the 6-point scoring system was 5.1, and bony formation was found to score at least 4 points in all patients. There was no case with implant-related complications such as cage failure or migration, and no complications associated with the use of CGDBM100. ACDF using CGDBM100 demonstrated good clinical and radiologic outcomes. The fusion rate was comparable with the published results of traditional ACDF. Therefore, the results of this study suggest that the use of a PEEK cage packed with DBM for ACDF is a safe and effective alternative to the gold standard of autologous iliac bone graft.

  12. Surgical Outcomes of Anterior Cervical Fusion Using Deminaralized Bone Matrix as Stand-Alone Graft Material: Single Arm, Pilot Study

    PubMed Central

    Chung, Ho-Jung; Ryu, Kyeong-Sik; Kim, Jin-Sung; Seong, Ji-Hoon

    2016-01-01

    Objective To investigate the safety and efficacy of demineralized bone matrix (DBM) as a bone graft substitute for anterior cervical discectomy and fusion (ACDF) surgery. Methods Twenty consecutive patients treated with ACDF using stand-alone polyestheretherketone (PEEK) cages (Zero-P) with DBM(CGDBM100) were prospectively evaluated with a minimum of 6 months of follow-up. Radiologic efficacy was evaluated with a 6-point scoring method for osseous fusion using plain radiograph and computed tomogrpahy scans. Clinical efficacy was evaluated using the visual analogue scale (VAS), Owestry disability index (ODI), and short-form health questionnaire-36. The safety of the bone graft substitute was assessed with vital sign monitoring and a survey measuring complications at each follow-up visit. Results There were significant improvements in VAS and ODI scores at a mean 6-month follow-up. Six months after surgery, solid fusion was achieved in all patients. Mean score on the 6-point scoring system was 5.1, and bony formation was found to score at least 4 points in all patients. There was no case with implant-related complications such as cage failure or migration, and no complications associated with the use of CGDBM100. Conclusion ACDF using CGDBM100 demonstrated good clinical and radiologic outcomes. The fusion rate was comparable with the published results of traditional ACDF. Therefore, the results of this study suggest that the use of a PEEK cage packed with DBM for ACDF is a safe and effective alternative to the gold standard of autologous iliac bone graft. PMID:27799989

  13. [Anterior cervical hypertrichosis: case report].

    PubMed

    Orozco-Gutiérrez, Mario H; Sánchez-Corona, José; García-Ortiz, José E; Castañeda-Cisneros, Gema; Dávalos-Rodríguez, Nory O; Corona-Rivera, Jorge R; García-Cruz, Diana

    2016-10-01

    The non-syndromic anterior cervical hypertrichosis (OMIM N° 600457) is a genetic disorder characterized by a patch of hair at the level of the laryngeal prominence. We present a 12-year-old boy with anterior cervical hypertrichosis and mild generalized hypertrichosis. He has no neurological, ophthalmological or skeletal anomalies. The clinical follow up is 10 years.

  14. MRI and PET Imaging in Predicting Treatment Response in Patients With Stage IB-IVA Cervical Cancer

    ClinicalTrials.gov

    2017-06-27

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma, Not Otherwise Specified; Cervical Undifferentiated Carcinoma; Recurrent Cervical Carcinoma; Stage IB2 Cervical Cancer; Stage II Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IIIA Cervical Cancer; Stage IIIB Cervical Cancer; Stage IVA Cervical Cancer

  15. Arrow trauma to cervical spine.

    PubMed

    Geissinger, Gregory; Magid, Gail A; McMahon, Robert C

    2009-07-01

    A 50-year-old man was the victim of an accidental arrow shooting while hunting. The arrow entered his posterolateral neck and came to rest in the space between the C1/C2 vertebrae in his cervical spine. He was able to maintain his own cervical immobilization. His hunting partners drove him to meet emergency medical technicians, who stabilized the arrow shaft, transferred him to a backboard and gurney, and continued manual cervical immobilization en route to a local hospital. Cervical spine X-ray results compelled an air ambulance transfer to a trauma center where he underwent surgical intervention to remove the arrow. Following approximately 12 months of physical and occupational therapy, he returned to work full-time. Adherence to training and utilization of proven techniques involving pre-hospital transfers and positioning of cervically injured patients proved imperative to the patient's ultimate recovery.

  16. Cervical carcinoma: an experimental approach.

    PubMed

    Cowan, M E; Skinner, G R

    1988-01-01

    A mouse model system was used to investigate the preventive efficacy of a subunit herpes simplex virus (HSV) vaccine on the development of HSV induced cervical carcinoma. Ten groups of mice were vaccinated before receiving repeated intravaginal exposure to HSV-type 2 inactivated by ultraviolet irradiation. At 20 months postvaccination, neutralizing antibody activity to herpes simplex viruses was detected in the sera of the mice which had received the highest vaccine dose. Although three experimental mice and one control mouse developed cervical tumours and five mice developed preinvasive malignant changes, 87% of cervices were of normal or koilocytotic appearance on histological examination. There was therefore no evidence from this study that repeated exposure of mouse cervices to inactivated HSV-2 induced a significant incidence of preinvasive or invasive cervical carcinoma.

  17. The cervical cap.

    PubMed

    1988-10-07

    The US Food and Drug Administration has approved marketing of the Prentif cavity-rim cervical cap. This contraceptive device is being distributed in the US and Canada by Cervical Cap Ltd, Los Gatos, California. The Prentif cap is available in 4 sizes: 22, 25, 28, and 31 mm inside diameter, with a length of 1 1/4-1 1/2 inches. In a multicenter trial involving 522 diaphragm users and 581 cap users followed for 2 years, the cap was 82.6% effective and the diaphragm was 83.3% effective in preventing pregnancy. When pregnancies attributable to user failure were excluded, these rates were increased to 93.6% for the cap and 95.4% for the diaphragm. 4% of cap users compared with only 1.7% of diaphragm users in this study developed abnormal Pap smears after 3 months of use; in addition, a higher proportion of cap users became infected with Gardnerella vaginalis and Monilia. Theoretical hazards include toxic shock syndrome and endometriosis due to backflow of menstrual fluids. Cap users are advised to undergo a Pap test after 3 months of use and discontinue cap use if the results are abnormal. The cap should not be used during menstruation. Although the cap can be left in place for up to 48 hours, its position should be checked before and after each episode of intercourse. The cervical cap requires less spermicide than the diaphragm and is not as messy. In addition, it can be left in the vagina twice as long as the diaphragm, without additional spermicide. Since the cap is smaller than the diaphragm and does not cover the vaginal wall, some women find intercourse more pleasurable with this device.

  18. Fractures of the cervical spine

    PubMed Central

    Marcon, Raphael Martus; Cristante, Alexandre Fogaça; Teixeira, William Jacobsen; Narasaki, Douglas Kenji; Oliveira, Reginaldo Perilo; de Barros Filho, Tarcísio Eloy Pessoa

    2013-01-01

    OBJECTIVES: The aim of this study was to review the literature on cervical spine fractures. METHODS: The literature on the diagnosis, classification, and treatment of lower and upper cervical fractures and dislocations was reviewed. RESULTS: Fractures of the cervical spine may be present in polytraumatized patients and should be suspected in patients complaining of neck pain. These fractures are more common in men approximately 30 years of age and are most often caused by automobile accidents. The cervical spine is divided into the upper cervical spine (occiput-C2) and the lower cervical spine (C3-C7), according to anatomical differences. Fractures in the upper cervical spine include fractures of the occipital condyle and the atlas, atlanto-axial dislocations, fractures of the odontoid process, and hangman's fractures in the C2 segment. These fractures are characterized based on specific classifications. In the lower cervical spine, fractures follow the same pattern as in other segments of the spine; currently, the most widely used classification is the SLIC (Subaxial Injury Classification), which predicts the prognosis of an injury based on morphology, the integrity of the disc-ligamentous complex, and the patient's neurological status. It is important to correctly classify the fracture to ensure appropriate treatment. Nerve or spinal cord injuries, pseudarthrosis or malunion, and postoperative infection are the main complications of cervical spine fractures. CONCLUSIONS: Fractures of the cervical spine are potentially serious and devastating if not properly treated. Achieving the correct diagnosis and classification of a lesion is the first step toward identifying the most appropriate treatment, which can be either surgical or conservative. PMID:24270959

  19. X-Ray Exam: Cervical Spine

    MedlinePlus

    ... to 2-Year-Old X-Ray Exam: Cervical Spine KidsHealth > For Parents > X-Ray Exam: Cervical Spine Print A A A What's in this article? ... Radiografía: columna cervical What It Is A cervical spine X-ray is a safe and painless test ...

  20. [Subcutaneous cervical emphysema secondary to tooth extraction].

    PubMed

    Calvo Boizas, E; Sancipriano Hernández, J A; Rincón Esteban, L; Diego Pérez, C; Santiago Andrés, J; Hermosa Finamor, P; Gómez Toranzo, F

    1997-01-01

    Cervical emphysema is rare and its diagnosis involves the ENT specialist. A case of cervical subcutaneous emphysema secondary to lower molar extraction is reported. The patient had no signs or symptoms other than cervical emphysema. Simple radiography and CT are recommended for early diagnosis. The etiopathogenic mechanisms of subcutaneous cervical emphysema are reviewed. Recent literature contains few cases of dental origin.

  1. X-Ray Exam: Cervical Spine

    MedlinePlus

    ... to 2-Year-Old X-Ray Exam: Cervical Spine KidsHealth > For Parents > X-Ray Exam: Cervical Spine A A A What's in this article? What ... Radiografía: columna cervical What It Is A cervical spine X-ray is a safe and painless test ...

  2. [Cervical spine instability in the surgical patient].

    PubMed

    Barbeito, A; Guerri-Guttenberg, R A

    2014-03-01

    Many congenital and acquired diseases, including trauma, may result in cervical spine instability. Given that airway management is closely related to the movement of the cervical spine, it is important that the anesthesiologist has detailed knowledge of the anatomy, the mechanisms of cervical spine instability, and of the effects that the different airway maneuvers have on the cervical spine. We first review the normal anatomy and biomechanics of the cervical spine in the context of airway management and the concept of cervical spine instability. In the second part, we review the protocols for the management of cervical spine instability in trauma victims and some of the airway management options for these patients.

  3. Cervical extravasation of bevacizumab.

    PubMed

    Dréanic, Johann; Coriat, Romain; Mir, Olivier; Perkins, Géraldine; Boudou-Rouquette, Pascaline; Brezault, Catherine; Dhooge, Marion; Goldwasser, François; Chaussade, Stanislas

    2013-04-01

    Monoclonal antibodies such as bevacizumab are widely used in medical oncology, either alone or in combination with chemotherapy. No specific recommendations on the management of monoclonal antibodies extravasation exist. Incidence rates vary considerably. Estimates of 0.5-6% have been reported in the literature. Also, patient-associated and procedure-associated risk factors of extravasation are multiple, such as bolus injections or poorly implanted central venous access. We report on an 86-year-old woman with colon cancer with liver metastasis who was treated with 5-fluorouracil, folinic acid, and bevacizumab. Extravasation occurred during chemotherapy infusion because of a catheter migration of the port outside of the superior vena cava, causing cervical pain without skin modifications. Diagnosis was confirmed with the appearance of clinical right cervical tumefaction and cervicothoracic computed tomography scan indicated a perijugular hypodense collection, corresponding to the extravasation. Conservative management was proposed. The patient recovered within 3 weeks from all symptoms. Physicians should be aware that in cases of bevacizumab extravasation, a nonsurgical approach might be effective.

  4. Antibacterial and Bioactive Coatings Based on Radio Frequency Co-Sputtering of Silver Nanocluster-Silica Coatings on PEEK/Bioactive Glass Layers Obtained by Electrophoretic Deposition.

    PubMed

    Ur Rehman, Muhammad Atiq; Ferraris, Sara; Goldmann, Wolfgang H; Perero, Sergio; Bastan, Fatih Erdem; Nawaz, Qaisar; Confiengo, G Gautier di; Ferraris, Monica; Boccaccini, Aldo R

    2017-09-27

    Bioactive and antibacterial coatings on stainless steel substrates were developed and characterized in this study. Silver nanocluster-silica composite coatings of 60-150 nm thickness were deposited using radio frequency (RF) co-sputtering on PEEK/bioactive glass (BG) layers (of 80-90 μm thickness) which had been electrophoretically deposited onto stainless steel. Two sputtering conditions were used by varying the deposition time (15 and 40 min); the resulting microstructure, composition, adhesion strength, in vitro bioactivity, and antibacterial activity were investigated. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive spectroscopy (EDX) confirmed the presence of silver nanoclusters, which were homogeneously embedded in the silica matrix. The isoelectric point of the coatings and their charge at physiological pH were determined by zeta potential measurements. The presence of BG particles in the PEEK/BG layer allows the coatings to form apatite-like crystals upon immersion in simulated body fluid (SBF). Moreover, silver nanoclusters embedded in the silica matrix as a top layer provided an antibacterial effect against Escherichia coli and Staphylococcus carnosus.

  5. Dysphagia due to cervical osteophytes.

    PubMed

    Khan, Mohammad Saeed; Bansal, Meghana; Agarwal, Abhishek

    2012-05-01

    Cervical bony outgrowths or osteophytes are common and usually asymptomatic. In some cases, they may be associated with dysphagia, dysphonia, dyspnea and pulmonary aspiration. The most common causes of cervical osteophytes are osteoarthritis, ankylosing spondylitis and ankylosing hyperostosis or Diffuse Idiopathic Spinal Hyperostosis (DISH), also known as Forestier's Disease. Other causes are hypoparathyroidism, trauma, acromegaly, ochronosis and flourosis. However, while dysphagia due to osteophytes is reported in the setting of DISH, it is very rare with osteoarthritis. We report a case of a patient who developed dysphagia due to anterior cervical osteophytes in the setting of osteoarthritis.

  6. Cervical spine injuries in football.

    PubMed

    Breslow, M J; Rosen, J E

    2000-01-01

    The game of football, as it is played today, poses serious risk of injury for players of all ages. Injury may occur to any structure of the spinal column, including its bony, ligamentous and soft tissue components. The majority of cervical spine injuries occurring in football are self limited, and a full recovery can be expected. While these injuries are relatively uncommon, cervical spine injuries represent a significant proportion of athletic injuries that can produce permanent disability. The low incidence of cervical spine injuries has lead to a lack of emergency management experience of on-site medical staff. This paper will review the numerous injuries sustained by the cervical spine in football players and provide insights into prevention and guidelines for return to play.

  7. Cervical Dysplasia: Is It Cancer?

    MedlinePlus

    ... showed cervical dysplasia. What does that mean? Is it cancer? Answers from Shannon K. Laughlin-Tommaso, M. ... or glandular cells. Dysplasia could go away on its own. Or, rarely, it could develop into cancer. ...

  8. Advocating for cervical cancer prevention.

    PubMed

    Sherris, J; Agurto, I; Arrossi, S; Dzuba, I; Gaffikin, L; Herdman, C; Limpaphayom, K; Luciani, S

    2005-05-01

    Cervical cancer is a significant health problem among women in developing countries. Contributing to the cervical cancer health burden in many countries is a lack of understanding and political will to address the problem. Broad-based advocacy efforts that draw on research and program findings from developing-country settings are key to gaining program and policy support, as are cost-effectiveness analyses based on these findings. The Alliance for Cervical Cancer Prevention (ACCP) has undertaken advocacy efforts at the international, regional, national, and local levels to raise awareness and understanding of the problem (and workable solutions), galvanize funders and governments to take action, and engage local stakeholders in ensuring program success. ACCP experience demonstrates the role that evidence-based advocacy efforts play in the ultimate success of cervical cancer prevention programs, particularly when new screening and treatment approaches-and, ultimately, radically new approaches such as a human papillomavirus vaccine-are available.

  9. Cervical Stenosis, Myelopathy and Radiculopathy

    MedlinePlus

    ... between the vertebrae results in narrowing of the space for the spinal cord and its branches, known ... and cervical stenosis refers to narrowing of the space for the spinal cord or nerve branches in ...

  10. Human papillomavirus and cervical cancer.

    PubMed

    Crook, T; Farthing, A

    Cervical cancer is the fifth most common cancer worldwide, and is second only to breast cancer as the leading cause of cancer deaths in women. Half a million cases are diagnosed annually with the highest rates in developing countries.

  11. Cervical Cancer Screening - Multiple Languages

    MedlinePlus

    ... Supplements Videos & Tools You Are Here: Home → Multiple Languages → All Health Topics → Cervical Cancer Screening URL of this page: https://medlineplus.gov/languages/cervicalcancerscreening.html Other topics A-Z Expand Section ...

  12. Airway management for cervical spine surgery.

    PubMed

    Farag, Ehab

    2016-03-01

    Cervical spine surgery is one of the most commonly performed spine surgeries in the United States, and 90% of the cases are related to degenerative cervical spine disease (the rest to cervical spine trauma and/or instability). The airway management for cervical spine surgery represents a crucial step in the anesthetic management to avoid injury to the cervical cord. The crux for upper airway management for cervical spine surgery is maintaining the neck in a neutral position with minimal neck movement during endotracheal intubation. Therefore, the conventional direct laryngoscopy (DL) can be unsuitable for securing the upper airway in cervical spine surgery, especially in cases of cervical spine instability and myelopathy. This review discusses the most recent evidence-based facts of the main advantages and limitations of different techniques available for upper airway management for cervical spine surgery.

  13. [Pregnancy and invasive cervical cancer].

    PubMed

    Kornovski, Ia; Gorchev, G; Trendafilova

    2008-01-01

    A case of 27-year old woman with spinocellular cervical cancer stage IB1 (FIGO) associated with pregnancy (36 g.w.) was reported. Authors performed cesarean radical hysterectomy with pelvic lymphadenectomy and transposition of the ovaries. The review of the literature revealed an algorithm and and practical recommendations in terms of management of cervical cancer during pregnancy, depending on the stage of the pregnancy and the tumor.

  14. [Current perspectives in cervical cancer].

    PubMed

    Valdespino Gómez, Víctor M; Valdespino Castillo, Víctor E

    2004-01-01

    Cervical cancer is a Public Health problem among women worldwide, especially in the developing world. The understanding of the HPV association with the high-grade squamous intraepithelial lesions and cervical cancer and the knowledge of the pre-invasive lesions natural history have strengthened the justification of different means of cancer prevention and screening programs, the application of different pre-invasive lesion treatments and particularly advances in conventional treatments of cervical cancer. In the last thirty years, cervical cancer's incidence and mortality rates have decreased in more than 75% in developed nations due to efficient application of secondary prevention based on cytology and colposcopy screening programs plus to in-office implementation of precursor lesions treatment methods. In the developing nations, these achievements can be obtained using specific steps of primary prevention, massive participation of risk patients in screening programs and improving ambulatory application of pre-invasive cervical lesion treatments. In Mexico several indicators suggest that this condition has began. New knowledge paradigms of the local immune response to HPV-cervical cancer pre-invasive and invasive lesions are being added to the construction of new preventive and therapeutic anti-cancer strategies. The preventive vaccines anti-high risk oncogenic-HPVs offer a good perspective in short term, also the use of different cellular immunotherapy strategies anti-cervical cancer as adyuvant of conventional treatments offer an encouraging panorama in not long term. In the next years, the improving of specific genes determination and their correlation with biologic features of the specific tumor which are involved on pre-invasive and invasive stages of cervical cancer will raise the understanding and the treatment of these patients.

  15. Cervical Vagal Schwannoma: Anesthetic Concerns

    PubMed Central

    Saini, Suman; Sabharwal, Nikki; Agrawal, Nidhi; Singh, Bhupender

    2017-01-01

    Schwannomas arising from cervical vagus nerve is an extremely rare benign neoplasm. The majority of patients present with insidiously growing lateral neck mass without neurological deficit. We report a case of symptomatic cervical vagal nerve schwannoma in a 32-year-old female. Complete surgical resection is the treatment of choice. However, anesthetic management of these tumors can be challenging. We describe here the complications experienced during the management of the patient.

  16. Glycoprotein and Glycan in Tissue and Blood Samples of Patients With Stage IB-IVA Cervical Cancer Undergoing Surgery to Remove Pelvic and Abdominal Lymph Nodes

    ClinicalTrials.gov

    2016-10-26

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Small Cell Carcinoma; Cervical Squamous Cell Carcinoma, Not Otherwise Specified; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  17. Cervical spine injury: tiger attack.

    PubMed

    Anderson, Meredith; Utter, Philip; Szatkowski, Jan; Patrick, Todd; Duncan, William; Turner, Norman; Dekutoski, Mark

    2008-12-01

    Reports of tiger attacks in the United States are rare. This article presents a case of a young woman who was violently attacked by a Siberian tiger and sustained penetrating trauma to the neck, cervical spine, and bilateral lower extremities. This article presents both diagnostic and therapeutic management of patients who may present with similar injuries. Animal bites from large animals are prone to infection in 10% to 20% of cases. Most infections are polymicrobial, with Pasteurella multicida being the most common isolate. Animal bites also mandate consideration of tetanus and rabies prophylaxis. The decision to administer postexposure rabies prophylaxis is dependent on the type of animal involved, whether the exposure was provoked, the local epidemiology of rabies, and the availability of the animal for observation or testing. Assessment of patients with cervical spine injury requires knowledge of possible associated injuries. Evaluation involves assessment of plain radiographs and computed tomography for evaluation of the cervical spine for bony injury. Furthermore, computed angiography is advantageous to noninvasively evaluate carotid or vertebral artery injury at the same setting in patients with deep cervical puncture wounds. Surgical treatment of unstable cervical spine fractures with lateral mass screw and rod fixation has been reported in the literature to have superior biomechanical properties compared to anterior and posterior instrumentation and fusion. In recent clinical studies, the use of lateral mass screws for traumatic injury of the cervical spine has been associated with excellent maintenance of alignment and minimal complications.

  18. Cervical total disk replacement: complications and avoidance.

    PubMed

    Salari, Behnam; McAfee, Paul C

    2012-01-01

    Anterior cervical diskectomy and fusion for neurologic deficits, radicular arm pain, and neck pain refractory to conservative management are successful. The approach and procedure were first described in 1955 and have become the anterior cervical standard of care for orthopedic surgeons and neurosurgeons. Advancements and innovations have addressed disease processes of the cervical spine with motion-preserving technology. The possibility of obtaining anterior cervical decompression while maintaining adjacent segment motion led to the advent of cervical total disk replacement. The Food and Drug Administration has approved 3 cervical devices with other investigational device exemption trials under way.

  19. Pathogenesis, Diagnosis, and Treatment of Cervical Vertigo.

    PubMed

    Li, Yongchao; Peng, Baogan

    2015-01-01

    Cervical vertigo is characterized by vertigo from the cervical spine. However, whether cervical vertigo is an independent entity still remains controversial. In this narrative review, we outline the basic science and clinical evidence for cervical vertigo according to the current literature. So far, there are 4 different hypotheses explaining the vertigo of a cervical origin, including proprioceptive cervical vertigo, Barré-Lieou syndrome, rotational vertebral artery vertigo, and migraine-associated cervicogenic vertigo. Proprioceptive cervical vertigo and rotational vertebral artery vertigo have survived with time. Barré-Lieou syndrome once was discredited, but it has been resurrected recently by increased scientific evidence. Diagnosis depends mostly on patients' subjective feelings, lacking positive signs, specific laboratory examinations and clinical trials, and often relies on limited clinical experiences of clinicians. Neurological, vestibular, and psychosomatic disorders must first be excluded before the dizziness and unsteadiness in cervical pain syndromes can be attributed to a cervical origin. Treatment for cervical vertigo is challenging. Manual therapy is recommended for treatment of proprioceptive cervical vertigo. Anterior cervical surgery and percutaneous laser disc decompression are effective for the cervical spondylosis patients accompanied with Barré-Liéou syndrome. As to rotational vertebral artery vertigo, a rare entity, when the exact area of the arterial compression is identified through appropriate tests such as magnetic resonance angiography (MRA), computed tomography angiography (CTA) or digital subtraction angiography (DSA) decompressive surgery should be the chosen treatment.

  20. Analysis of digitized cervical images to detect cervical neoplasia

    NASA Astrophysics Data System (ADS)

    Ferris, Daron G.

    2004-05-01

    Cervical cancer is the second most common malignancy in women worldwide. If diagnosed in the premalignant stage, cure is invariably assured. Although the Papanicolaou (Pap) smear has significantly reduced the incidence of cervical cancer where implemented, the test is only moderately sensitive, highly subjective and skilled-labor intensive. Newer optical screening tests (cervicography, direct visual inspection and speculoscopy), including fluorescent and reflective spectroscopy, are fraught with certain weaknesses. Yet, the integration of optical probes for the detection and discrimination of cervical neoplasia with automated image analysis methods may provide an effective screening tool for early detection of cervical cancer, particularly in resource poor nations. Investigative studies are needed to validate the potential for automated classification and recognition algorithms. By applying image analysis techniques for registration, segmentation, pattern recognition, and classification, cervical neoplasia may be reliably discriminated from normal epithelium. The National Cancer Institute (NCI), in cooperation with the National Library of Medicine (NLM), has embarked on a program to begin this and other similar investigative studies.

  1. "This I Suffered in the Short Space of my Life". The Epitaph for Lucius Minicius Anthimianus (CIG 3272; Peek GVn 1166).

    PubMed

    Graumann, Lutz A; Horstmanshoff, Manfred

    2016-01-01

    Herewith we present an interdisciplinary study of the metrical funerary inscription from the third century CE (CIG 3272; Peek GV 1166). This emotional Greek epitaph reports the short life (from birth to death) of the 4 year old Lucius Minicius Anthimianus. This is the first detailed study since the dissertation by Klitsch (1976). The inscription presents an ideal case for a truly interdisciplinary study of the patient-history, in that its interpretation involves the study of Greek literature and linguistics, epigraphy, social and religious history, and ancient medicine. It also offers ample opportunity to show the contradictions inherent in proposing retrospective diagnosis, without neglecting the relevant information modern medicine has to offer for the interpretation of this case history. We argue that Lucius' father was most probably a physician, that the text of the inscription stems from expert knowledge of ancient medicine and that the traditional retrospective diagnosis of this case, tuberculosis, is an untenable hypothesis.

  2. Peeking over Saturn Shoulder

    NASA Image and Video Library

    2017-01-16

    No Earth-based telescope could ever capture a view quite like this. Earth-based views can only show Saturn's daylit side, from within about 25 degrees of Saturn's equatorial plane. A spacecraft in orbit, like Cassini, can capture stunning scenes that would be impossible from our home planet. This view looks toward the sunlit side of the rings from about 25 degrees (if Saturn is dominant in image) above the ring plane. The image was taken in violet light with the Cassini spacecraft wide-angle camera on Oct. 28, 2016. The view was obtained at a distance of approximately 810,000 miles (1.3 million kilometers) from Saturn. Image scale is 50 miles (80 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20517

  3. Peeking at the Planets.

    ERIC Educational Resources Information Center

    Riddle, Bob

    2002-01-01

    Provides information about each of the planets in our solar system. Focuses on information related to the space missions that have visited or flown near each planet, and includes a summary of what is known about some of the features of each planet. (DDR)

  4. Cervical Flexion Myelopathy Eleven Years after a Cervical Spinal Cord Injury.

    PubMed

    Nakano, Hiroto; Sakai, Kenji; Iwasa, Kazuo; Yamada, Masahito

    2017-08-15

    We herein describe a 37-year-old man who developed cervical flexion myelopathy 11 years after suffering a cervical spinal cord injury. Cervical magnetic resonance imaging 11 years after the accident demonstrated atrophy and hyperintense lesions at the C6 and C7 levels in the cervical cord with an abnormal alignment of the vertebrae. In the neck flexion position, an anterior shift of the cervical cord was evident. Our patient's condition suggests that an abnormal alignment of the cervical spine and spinal cord injury due to a traumatic accident could be risk factors in the subsequent development of cervical flexion myelopathy.

  5. Preventing Cervical Cancer with HPV Vaccines

    Cancer.gov

    Cervical cancer can be prevented with HPV vaccines. NCI-supported researchers helped establish HPV as a cause of cervical cancer. They also helped create the first HPV vaccines, were involved in the vaccine trials, and contribute to ongoing studies.

  6. Internet-Based Cervical Cytology Screening System

    DTIC Science & Technology

    2007-04-01

    telecytology, cytopathology, telemedicine, cancer screening, health care information systems, cervical cancer 16. SECURITY CLASSIFICATION OF......approaches to cervical cancer screening possible. In addition, advances in information technology have facilitated the Internet transmission and archival

  7. Cervical Spine Injuries in the Athlete.

    PubMed

    Schroeder, Gregory D; Vaccaro, Alexander R

    2016-09-01

    Cervical spine injuries are extremely common and range from relatively minor injuries, such as cervical muscle strains, to severe, life-threatening cervical fractures with spinal cord injuries. Although cervical spine injuries are most common in athletes who participate in contact and collision sports, such as American football and rugby, they also have been reported in athletes who participate in noncontact sports, such as baseball, gymnastics, and diving. Cervical spine injuries in athletes are not necessarily the result of substantial spine trauma; some athletes have chronic conditions, such as congenital stenosis, that increase their risk for a serious cervical spine injury after even minor trauma. Therefore, physicians who cover athletic events must have a thorough knowledge of cervical spine injures and the most appropriate ways in which they should be managed. Although cervical spine injuries can be career-ending injuries, athletes often are able to return to play after appropriate treatment if the potential for substantial re-injury is minimized.

  8. Cervical cancer screening.

    PubMed Central

    Katz, A.

    1998-01-01

    OBJECTIVE: To review the role of family physicians in screening for cancer of the cervix, to review the evidence for screening, in particular, frequency and technique for screening, and to review the reasons cervical cancer has not been prevented and the role of family physicians in addressing these failures. QUALITY OF EVIDENCE: The value of screening has been established with level II evidence. Many of the unresolved issues are not supported either way by good evidence; level II and III evidence predominates. MAIN FINDINGS: In Canada, 1350 women were predicted to be diagnosed with cancer of the cervix in 1996. Most of these women had not been screened. Minority, rural, low-income, and older women face important barriers to screening. Family physicians have a role in reaching out to these women to provide effective health care, including cancer screening. When cancer screening is performed, it should conform to recommended techniques with appropriate follow up of abnormal test results. CONCLUSIONS: Family physicians have an important role in preventing cancer of the cervix. Efforts should be concentrated on encouraging a greater proportion of eligible women to be screened. Criteria are suggested for effective screening. PMID:9721422

  9. Cervical interfacet spacers and maintenance of cervical lordosis.

    PubMed

    Tan, Lee A; Straus, David C; Traynelis, Vincent C

    2015-05-01

    OBJECT The cervical interfacet spacer (CIS) is a relatively new technology that can increase foraminal height and area by facet distraction. These offer the potential to provide indirect neuroforaminal decompression while simultaneously enhancing fusion potential due to the relatively large osteoconductive surface area and compressive forces exerted on the grafts. These potential benefits, along with the relative ease of implantation during posterior cervical fusion procedures, make the CIS an attractive adjuvant in the management of cervical pathology. One concern with the use of interfacet spacers is the theoretical risk of inducing iatrogenic kyphosis. This work tests the hypothesis that interfacet spacers are associated with loss of cervical lordosis. METHODS Records from patients undergoing posterior cervical fusion at Rush University Medical Center between March 2011 and December 2012 were reviewed. The FacetLift CISs were used in all patients. Preoperative and postoperative radiographic data were reviewed and the Ishihara indices and cervical lordotic angles were measured and recorded. Statistical analyses were performed using STATA software. RESULTS A total of 64 patients were identified in whom 154 cervical levels were implanted with machined allograft interfacet spacers. Of these, 15 patients underwent anterior-posterior fusions, 4 underwent anterior-posterior-anterior fusions, and the remaining 45 patients underwent posterior-only fusions. In the 45 patients with posterior-only fusions, a total of 110 levels were treated with spacers. There were 14 patients (31%) with a single level treated, 16 patients (36%) with two levels treated, 5 patients (11%) with three levels treated, 5 patients (11%) with four levels treated, 1 patient (2%) with five levels treated, and 4 patients (9%) with six levels treated. Complete radiographic data were available in 38 of 45 patients (84%). On average, radiographic follow-up was obtained at 256.9 days (range 48-524 days

  10. Cervical Spinal Motion During Orotracheal Intubation.

    DTIC Science & Technology

    1998-01-01

    Sixteen fresh human cadavers were intubated while recording cervical motion using a cine fluoroscopic technique. Segmental cervical motion from the...intubation was performed using no external stabilization, Gardner-Wells traction and manual in-line cervical immobilization. The cadaveric spine motion...immobilization reduced motion at the destabilize C4-5 level. Four patients without significant cervical pathology and normal motion of flexion

  11. Cervical cancer screening at crossroads.

    PubMed

    Lynge, Elsebeth; Rygaard, Carsten; Baillet, Miguel Vazquez-Prada; Dugué, Pierre-Antoine; Sander, Bente Braad; Bonde, Jesper; Rebolj, Matejka

    2014-08-01

    Cervical screening has been one of the most successful public health prevention programmes. For 50 years, cytology formed the basis for screening, and detected cervical intraepithelial lesions (CIN) were treated surgically to prevent progression to cancer. In a high-risk country as Denmark, screening decreased the incidence of cervical cancer from 34 to 11 per 100,000, age-standardized rate (World Standard Population). Screening is, however, also expensive; Denmark (population: 5.6 million) undertakes close to half a million tests per year, and has 6-8 CIN-treated women for each prevented cancer case. The discovery of human papillomavirus (HPV) as the cause of cervical cancer dramatically changed perspectives for disease control. Screening with HPV testing was launched around 1990, and preventive HPV vaccination was licensed in 2006. Long-term randomized controlled trials (RCT) demonstrated that HPV testing provides better protection against cervical cancer than cytology, but it requires extra repeated testing. HPV vaccination RCTs, furthermore, have proved that HPV vaccination protects against vaccine-type high-grade CIN in women vaccinated prior to sexual activity, but less so in women vaccinated later. The challenge now is therefore to find an algorithm for screening of a heterogeneous population including non-vaccinated women; women vaccinated prior to start of sexual activity; and women vaccinated later. © 2014 APMIS. Published by John Wiley & Sons Ltd.

  12. Human Papillomavirus and Cervical Cancer

    PubMed Central

    Burd, Eileen M.

    2003-01-01

    Of the many types of human papillomavirus (HPV), more than 30 infect the genital tract. The association between certain oncogenic (high-risk) strains of HPV and cervical cancer is well established. Although HPV is essential to the transformation of cervical epithelial cells, it is not sufficient, and a variety of cofactors and molecular events influence whether cervical cancer will develop. Early detection and treatment of precancerous lesions can prevent progression to cervical cancer. Identification of precancerous lesions has been primarily by cytologic screening of cervical cells. Cellular abnormalities, however, may be missed or may not be sufficiently distinct, and a portion of patients with borderline or mildly dyskaryotic cytomorphology will have higher-grade disease identified by subsequent colposcopy and biopsy. Sensitive and specific molecular techniques that detect HPV DNA and distinguish high-risk HPV types from low-risk HPV types have been introduced as an adjunct to cytology. Earlier detection of high-risk HPV types may improve triage, treatment, and follow-up in infected patients. Currently, the clearest role for HPV DNA testing is to improve diagnostic accuracy and limit unnecessary colposcopy in patients with borderline or mildly abnormal cytologic test results. PMID:12525422

  13. Use of Cervical Pessary in the Management of Cervical Insufficiency.

    PubMed

    Timofeev, Julia

    2016-06-01

    Prevention of spontaneous preterm birth is an important public health priority. Pessary may be a potential therapy in cases of cervical insufficiency, in singleton and multiple gestations. Availability of transvaginal sonography for accurate assessment of cervical length is allowing for the tailoring of therapy to a more specific subset of patients who may benefit from this treatment. Pessary therapy is attractive given the favorable side effect profile, low cost, and ease of placement and removal. Large randomized trials are ongoing to validate initial favorable findings.

  14. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix to...

  15. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix to...

  16. 21 CFR 884.3200 - Cervical drain.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cervical drain. 884.3200 Section 884.3200 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Prosthetic Devices § 884.3200 Cervical drain. (a) Identification. A cervical drain is a device designed to provide an exit channel for draining...

  17. 21 CFR 884.3200 - Cervical drain.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cervical drain. 884.3200 Section 884.3200 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Prosthetic Devices § 884.3200 Cervical drain. (a) Identification. A cervical drain is a device designed to provide an exit channel for draining...

  18. 21 CFR 884.3200 - Cervical drain.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cervical drain. 884.3200 Section 884.3200 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Prosthetic Devices § 884.3200 Cervical drain. (a) Identification. A cervical drain is a device designed to provide an exit channel for draining...

  19. 21 CFR 884.3200 - Cervical drain.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cervical drain. 884.3200 Section 884.3200 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Prosthetic Devices § 884.3200 Cervical drain. (a) Identification. A cervical drain is a device designed to provide an exit channel for draining...

  20. 21 CFR 884.3200 - Cervical drain.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cervical drain. 884.3200 Section 884.3200 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Prosthetic Devices § 884.3200 Cervical drain. (a) Identification. A cervical drain is a device designed to provide an exit channel for draining...

  1. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix to...

  2. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix to...

  3. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix...

  4. Cervical vertebral bone age in girls.

    PubMed

    Mito, Toshinori; Sato, Koshi; Mitani, Hideo

    2002-10-01

    The purpose of this study was to establish cervical vertebral bone age as a new index for objectively evaluating skeletal maturation on cephalometric radiographs. Using cephalometric radiographs of 176 girls (ages 7.0-14.9 years), we measured cervical vertebral bodies and determined a regression formula to obtain cervical vertebral bone age. Next, using cephalometric and hand-wrist radiographs of another 66 girls (ages 8.0-13.9 years), we determined the correlation between cervical vertebral bone age and bone age using the Tanner-Whitehouse 2 method. The following results were obtained: (1) a regression formula was determined to obtain cervical vertebral bone age based on ratios of measurements in the third and fourth cervical vertebral bodies; (2) the correlation coefficient for the relationship between cervical vertebral bone age and bone age (0.869) was significantly (P <.05) higher than that for the relationship between cervical vertebral bone age and chronological age (0.705); and (3) the difference (absolute value) between the cervical vertebral bone age and bone age (0.75 years) was significantly (P <.001) smaller than that between cervical vertebral bone age and chronological age (1.17 years). These results suggest that cervical vertebral bone age reflects skeletal maturity because it approximates bone age, which is considered to be the most reliable method for evaluating skeletal maturation. Using cervical vertebral bone age, it might be possible to evaluate maturity in a detailed and objective manner on cephalometric radiographs.

  5. [Therapeutic effect and mechanism of the surgical treatment for cervical vertigo with cervical spondylosis].

    PubMed

    Zhong, Zhuolin; Hu, Jianhua; Zhai, Jiliang; Tian, Ye; Qiu, Guixing; Weng, Xisheng; Wu, Gui; Zhu, Qiankun; Zhao, Lijuan

    2015-07-07

    To investigate the therapeutic effect and mechanism of the surgical treatment for cervical vertigo with cervical spondylosis. Thirty-five patients in Department of Orthopaedics, Peking Union Medical College Hospital, Peking Union Medical College, who received surgical treatment for cervical spondylosis concomitant with cervical vertigo from 2004 to 2013 were reviewed retrospectively. The preoperative cervical curvature index (CCI), slip distance and intervertebral angle, as well as the pre-and-postoperative Cobb angle were measured. The pre-and-postoperative degree of vertigo was reported according to the American Academy of Otolaryngology-Head and Neck Surgery Committee on Hearing and Equilibrium standard. The therapeutic effect and mechanism for patients with different imaging features and thus underwent various surgical approaches were analyzed. The mean follow-up was 40.6 months. Cervical instability was found in 33 patients. 29 of 35 (82.9%) patients had a satisfied recovery from cervical vertigo. The difference in Cobb angle in pre- and postoperative neutral cervical X-ray images was positively associated with the improvement for the vertigo (Pearson's test, P < 0.05). Cervical instability may be the major cause of cervical vertigo in the context of cervical spondylosis. Cervical sympathetic nerves may have played an important role in the cervical vertigo. Surgery may relieve the cervical vertigo accompanying the cervical spondylosis.

  6. The statics of cervical traction.

    PubMed

    Pio, A; Rendina, M; Benazzo, F; Castelli, C; Paparella, F

    1994-08-01

    The statics of a sliding body was used to study the distribution of forces during the application of cervical traction in supine patients. This theoretical analysis was completed using a dynamometer to determine the static friction between bed surface and patient head. Therefore, we measured the head weight in 12 inpatients and the minimum force that causes impending motion of the head on the bed surface. The static friction coefficient was calculated from the ratio of the two quantities. The forces acting on the cervical spine were determined by inserting the former data into a specifically designed algorithm that forecasted a progressively increasing traction angle. The coefficient of static friction was 0.62, whereas the maximum available force acting on the cervical spine was obtained with a 35 degrees traction inclination. In contrast, the forces dissipated by the plane progressively decreased with larger angles.

  7. Cervical Cancer Screening with AMIGAS

    PubMed Central

    Lairson, David R.; Chang, Yu-Chia; Byrd, Theresa L.; Smith, Judith Lee; Fernandez, Maria E.; Wilson, Katherine M.

    2015-01-01

    Background Hispanic women have a higher incidence of cervical cancer than all other races and ethnicities. In Hispanic subgroups, Mexican American women were among the least likely to have received cervical cancer screening. In a recent RCT, Ayudando a las Mujeres con Información, Guia, y Amor para su Salud (AMIGAS) was shown to increase cervical cancer screening rates among women of Mexican descent at 6 months in all intervention arms compared to the control arm. Limited information exists about the economics of interventions to increase cervical cancer screening rates among women of Mexican descent. Purpose This study aims to estimate the cost-effectiveness of the alternative AMIGAS intervention methods for increasing cervical cancer screening among low-income women of Mexican descent in three U.S. communities. Methods Cost data were collected from 2008 to 2011 alongside the AMIGAS study of 613 women. Receipt of Pap test within 6 months of intervention was the primary outcome measure in the cost-effectiveness analysis, conducted during 2012–2013. Results The cost per additional woman screened comparing the video-only intervention to usual care was $980. The cost increased to $1,309 with participant time cost included. With an additional cost per participant of $3.90 compared to flipchart only, the full AMIGAS program (video plus flipchart) yielded 6.8% additional women screened. Conclusions Results on the average and incremental cost-effectiveness of the AMIGAS program elements may assist health policymakers and program managers to select and appropriately budget for interventions shown to increase cervical cancer screening among low-income women of Mexican descent. PMID:24842738

  8. No Carious Cervical Lesions: Abfraction

    PubMed Central

    Shetty, Sumanth M; Shetty, Rashmi G; Mattigatti, Sudha; Managoli, Noopur A; Rairam, Surabhi G; Patil, Ashwini M

    2013-01-01

    Abfraction or Theory of Abfraction is a theory explaining the non-carious cervical lesions (NCCL). It suggests that they are caused by flexural forces, usually from cyclic loading; the enamel, especially at the cementoenamel junction (CEJ), undergoes this pattern of destruction by separating the enamel rods. Clinical aspect importance of these ineart lesions are at most important to be detected for early intervention and treatment modalities as options during the progression of the disease. How to cite this article: Shetty SM, Shetty RG, Mattigatti S, Managoli NA, Rairam SG, Patil AM. No Carious Cervical Lesions: Abfraction. J Int Oral Health 2013; 5(5):142-5. PMID:24324319

  9. No carious cervical lesions: abfraction.

    PubMed

    Shetty, Sumanth M; Shetty, Rashmi G; Mattigatti, Sudha; Managoli, Noopur A; Rairam, Surabhi G; Patil, Ashwini M

    2013-10-01

    Abfraction or Theory of Abfraction is a theory explaining the non-carious cervical lesions (NCCL). It suggests that they are caused by flexural forces, usually from cyclic loading; the enamel, especially at the cementoenamel junction (CEJ), undergoes this pattern of destruction by separating the enamel rods. Clinical aspect importance of these ineart lesions are at most important to be detected for early intervention and treatment modalities as options during the progression of the disease. How to cite this article: Shetty SM, Shetty RG, Mattigatti S, Managoli NA, Rairam SG, Patil AM. No Carious Cervical Lesions: Abfraction. J Int Oral Health 2013; 5(5):142-5.

  10. [Lithopedion in cervical pregnancy: a case report].

    PubMed

    Bustamante Sarabia, J; Flores Gil, O; Rubio, J E; Plata Nuñez, P

    1989-12-01

    One clinical case of cervical pregnancy studied, at the Hospital Regional ISSSTE in Acapulco, Guerrero, México, is presented. Clinically it was manifested as a true cervical pregnancy, with intermittent vaginal bleeding, fetid leukorrhea and slight pelvic pain. Literature reveals that diagnosis is rarely, if ever made, except by direct observation of the cervix. The case fulfills the Rubin's criteria for cervical pregnancy. Cervical pregnancy is extremely rare as evidenced by the paucity of cases in literature. Although it is an abnormal gestation, cervical pregnancy and a lithopedion formation makes this report rare and unique in world literature.

  11. Cervical spine in Treacher Collins syndrome.

    PubMed

    Pun, Amy Hoi-Ying; Clark, Bruce Eric; David, David John; Anderson, Peter John

    2012-05-01

    Treacher Collins syndrome is a congenital syndrome with characteristic craniofacial malformations, which are well described in the literature. However, the presence of cervical spine dysmorphology in this syndrome has been minimally described. This study reviews cervical spine radiographs of 40 patients with Treacher Collins syndrome. In this sample, 7 of 40 patients displayed cervical spine anomalies, with 3 of these patients displaying multiple cervical spine anomalies. The patterns of spinal anomalies were variable, suggesting that the underlying genetic mutation has variable expressivity in cervical spine development as it does elsewhere in the craniofacial skeleton.

  12. Cervical Whiplash: Considerations in the Rehabilitation of Cervical Myofascial Injury

    PubMed Central

    Ameis, Arthur

    1986-01-01

    Cervical whiplash, usually the result of impact injuries at high speed, is a typically 20th-century problem. This article describes the biomechanical stresses that result in whiplash and outlines the treatment programs that can be expected to help the patient through the four stages of recovery to achieve functional rehabilitation. PMID:21267293

  13. Percutaneous cervical nucleoplasty in the treatment of cervical disc herniation

    PubMed Central

    Li, Jian; Zhang, Zai-Heng

    2008-01-01

    Percutaneous disc decompression procedures have been performed in the past. Various percutaneous techniques such as percutaneous discectomy, laser discectomy, and nucleoplasty have been successful. Our prospective study was directly to evaluate the results of percutaneous cervical nucleoplasty (PCN) surgery for cervical disc herniation, and illustrate the effectiveness of PCN in symptomatic patients who had cervical herniated discs. From July of 2002 to June of 2005, 126 consecutive patients with contained cervical disc herniations have presented at the authors’ clinic and treated by PCN. The patients’ gender distribution for PCN was 65 male, 61 female. The age of patients ranged from 34 to 66 years (mean 51.9 ± 10.2 years). The levels of involvement were 21 cases at C3–4, 30 cases at C4–5, 40 cases at C5–6, and 35 cases at C6–7. The clinical outcomes, pain reduction and the segment stability were all recorded during this study. A clinical outcome was quantified by the Macnab standard and using VAS. The angular displacement (AD) ≥11° or horizontal displacement (HD) ≥3 mm was considered to be radiographically unstable. In the results of this study, puncture of the needle into the disc space was accurately performed under X-ray guidance in all cases. There was one case where the Perc-D Spine Wand had broken in the disc space during the procedure. The partial Perc-D Spine Wand, which had broken in the disc space could not be removed by the percutaneous cervical discectomy and thus remained there. There were no recurrent cases or complications in our series. Macnab standard results were excellent in 62 cases, good in 41 cases and fair in 23 cases. The rate of excellent and good was 83.73%. The VAS scores demonstrated statistically significant improvement in PCN at the 2-week, 1, 3, 6, and 12-month follow-up visits when compared to preoperational values (P < 0.01). There were no cases of instability following the PCN procedure. There was no

  14. Double Balloon Cervical Ripening Catheter for Control of Massive Hemorrhage in a Cervical Ectopic Pregnancy.

    PubMed

    Zambrano, Nabila; Reilly, James; Moretti, Michael; Lakhi, Nisha

    2017-01-01

    Cervical pregnancy can be complicated by perfuse vaginal bleeding. Mechanical compression directed at tamponing the cervical vessels can control hemostasis. There are several types of balloon catheters that have been described for cervical compression. However use of a double balloon catheter is a novel approach for cervical tamponade, as one balloon is positioned below the external cervical os and the second balloon is situated above in the internal cervical os. This compresses the cervix from internal os to external os between the two balloons, forming a "cervical sandwich." We describe this method of cervical tamponade using a silicone double balloon cervical ripening catheter that rapidly controlled hemorrhage in a patient that failed conservative management with methotrexate.

  15. Double Balloon Cervical Ripening Catheter for Control of Massive Hemorrhage in a Cervical Ectopic Pregnancy

    PubMed Central

    Zambrano, Nabila; Reilly, James; Moretti, Michael

    2017-01-01

    Cervical pregnancy can be complicated by perfuse vaginal bleeding. Mechanical compression directed at tamponing the cervical vessels can control hemostasis. There are several types of balloon catheters that have been described for cervical compression. However use of a double balloon catheter is a novel approach for cervical tamponade, as one balloon is positioned below the external cervical os and the second balloon is situated above in the internal cervical os. This compresses the cervix from internal os to external os between the two balloons, forming a “cervical sandwich.” We describe this method of cervical tamponade using a silicone double balloon cervical ripening catheter that rapidly controlled hemorrhage in a pa