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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 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

  2. Polyetheretherketone (PEEK) for medical applications.

    PubMed

    Panayotov, Ivan Vladislavov; Orti, Valérie; Cuisinier, Frédéric; Yachouh, Jacques

    2016-07-01

    Polyetheretherketone (PEEK) is a polyaromatic semi-crystalline thermoplastic polymer with mechanical properties favorable for bio-medical applications. Polyetheretherketone forms: PEEK-LT1, PEEK-LT2, and PEEK-LT3 have already been applied in different surgical fields: spine surgery, orthopedic surgery, maxillo-facial surgery etc. Synthesis of PEEK composites broadens the physicochemical and mechanical properties of PEEK materials. To improve their osteoinductive and antimicrobial capabilities, different types of functionalization of PEEK surfaces and changes in PEEK structure were proposed. PEEK based materials are becoming an important group of biomaterials used for bone and cartilage replacement as well as in a large number of diverse medical fields. The current paper describes the structural changes and the surface functionalization of PEEK materials and their most common biomedical applications. The possibility to use these materials in 3D printing process could increase the scientific interest and their future development as well. PMID:27259708

  3. Polyetheretherketone (PEEK) cage filled with cancellous allograft in anterior cervical discectomy and fusion

    PubMed Central

    Liao, Jen-Chung; Chen, Wen-Jer; Chen, Lih-Huei

    2007-01-01

    From July 2004 to June 2005, 19 patients with 25 discs underwent anterior cervical discectomy and interbody fusion (ACDF) in which polyetheretherketone (PEEK) cages were filled with freeze-dried cancellous allograft bone. This kind of bone graft was made from femoral condyle that was harvested during total knee arthroplasty. Patient age at surgery was 52.9 (28–68) years. All patients were followed up at least 1 year. We measured the height of the disc and segmental sagittal angulation by pre-operative and post-operative radiographs. CT scan of the cervical spine at 1 year was used to evaluate fusion rates. Odom's criteria were used to assess the clinical outcome. All interbody disc spaces achieved successful union at 1-year follow-up. The use of a PEEK cage was found to increase the height of the disc immediately after surgery (5.0 mm pre-operatively, 7.3 mm immediately post-operatively). The final disc height was 6.2 mm, and the collapse of the disc height was 1.1 mm. The segmental lordosis also increased after surgery (2.0° pre-operatively, 6.6° immediately post-operatively), but the mean loss of lordosis correction was 3.3° at final follow-up. Seventy-four percent of patients (14/19) exhibited excellent/good clinical outcomes. Analysis of the results indicated the cancellous allograft bone-filled PEEK cage used in ACDF is a good choice for patients with cervical disc disease, and avoids the complications of harvesting iliac autograft. PMID:17639386

  4. Fabrication of polyetheretherketone (PEEK) parts

    SciTech Connect

    Nelson, R.W.

    1991-12-01

    A literature search was conducted for polyetheretherketone (PEEK) thermoplastic to investigate its physical properties and molding applications. Simple molds were designed, built, and tested using PEEK molding compound. Molding parameters and shrink factors were determined. Physical properties varied with the percent of crystalline PEEK present. Annealing the molded parts enhanced their physical properties and increased the percent crystallinity. 11 refs.

  5. Polyetheretherketone (PEEK) Spacers for Anterior Cervical Fusion: A Retrospective Comparative Effectiveness Clinical Trial

    PubMed Central

    Lemcke, Johannes; Al-Zain, Ferass; Meier, Ullrich; Suess, Olaf

    2011-01-01

    Background: Anterior cervical decompression and fusion (ACDF) is the standard surgical treatment for radiculopathy and myelopathy. Polyetheretherketone (PEEK) has an elasticity similar to bone and thus appears well suited for use as the implant in ACDF procedures. The aim of this study is to examine the clinical and radiographic outcome of patients treated with standing alone PEEK spacers without bone morphogenic protein (BMP) or plating and to examine the influence of the different design of the two spacers on the rate of subsidence and dislocation. Methods: This retrospective comparative study reviewed 335 patients treated by ACDF in a specialized urban hospital for radiculopathy or myelopathy due to degenerative pathologies. The Intromed PEEK spacer was used in 181 patients from 3/2002 to 11/2004, and the AMT SHELL spacer was implanted in 154 patients from 4/2004 to 12/2007. The follow-up rate was 100% at three months post-op and 82.7% (277 patients) at one year. The patients were assessed with the Japanese Orthopedic Association (JOA) questionnaire and radiographically. Results: At the one-year follow-up there were 118/277 patients with an excellent clinical outcome on the JOA, 112/277 with a good outcome, 20/277 with a fair outcome, and 27/277 with a poor outcome. Subsidence was observed in 13.3% of patients with the Intromed spacer vs 8.4% of the patients with the AMT SHELL. Dislocation of the spacer was observed in 10 of the 181 patients with Intromed spacers but in none of the 154 patients with Shell spacers. Conclusion: The study demonstrates that ACDF with standing alone PEEK cages leads to excellent and good clinical outcomes. The differences we observed in the subsidence rate between the two spacers were not significant and cannot be related to a single design feature of the spacers. PMID:22016753

  6. 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

  7. 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

  8. Fabrication of polyetheretherketone (PEEK) parts. Final report

    SciTech Connect

    Nelson, R.W.

    1991-12-01

    A literature search was conducted for polyetheretherketone (PEEK) thermoplastic to investigate its physical properties and molding applications. Simple molds were designed, built, and tested using PEEK molding compound. Molding parameters and shrink factors were determined. Physical properties varied with the percent of crystalline PEEK present. Annealing the molded parts enhanced their physical properties and increased the percent crystallinity. 11 refs.

  9. 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.

  10. [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

  11. 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. PMID:26409233

  12. Thermal analyses of solvent-exposed poly(etheretherketone) (PEEK) composites

    SciTech Connect

    Whitaker, R.B.; Brown, C.R.; Carlson, R.S.; Trainer, P.D.

    1986-09-01

    Poly(etheretherketone) (PEEK) is a thermally stable, semicrystalline engineering thermoplastic resin which is used as a wire coating and as a fiberglass filled molding compound in Mound applications. Considerable characterization of its thermal, chemical, and crystalline structural properties has been done. The present study was undertaken, in order to determine the effect of solvents which could be encountered in normal processing of PEEK composites into Mound components on PEEK's physical, chemical and thermal properties.

  13. On the structure of poly(etheretherketone) (PEEK)

    NASA Technical Reports Server (NTRS)

    Wakelyn, N. T.

    1984-01-01

    Annealed, hot pressed, and melt-quenched PEEK specimens have been analyzed by wide-angle X-ray diffraction. The analysis suggests, in part, that structural studies based on the reported similarity between the structure of PEEK and that reported for poly(p-phenylene oxide) are valid and may be extended to a structure more in keeping with the chemical structure of the material.

  14. Polyetheretherketone (PEEK) rods: short-term results in lumbar spine degenerative disease.

    PubMed

    Colangeli, S; Barbanti Brodàno, G; Gasbarrini, A; Bandiera, S; Mesfin, A; Griffoni, C; Boriani, S

    2015-06-01

    Pedicle screw and rod instrumentation has become the preferred technique for performing stabilization and fusion in the surgical treatment of lumbar spine degenerative disease. Rigid fixation leads to high fusion rates but may also contribute to stress shielding and adjacent segment degeneration. Thus, the use of semirigid rods made of polyetheretherketone (PEEK) has been proposed. Although the PEEK rods biomechanical properties, such as anterior load sharing properties, have been shown, there are few clinical studies evaluating their application in the lumbar spine surgical treatment. This study examined a retrospective cohort of patients who underwent posterior lumbar fusion for degenerative disease using PEEK rods, in order to evaluate the clinical and radiological outcomes and the incidence of complications.

  15. Polyetheretherketone (PEEK) rods: short-term results in lumbar spine degenerative disease.

    PubMed

    Colangeli, S; Barbanti Brodàno, G; Gasbarrini, A; Bandiera, S; Mesfin, A; Griffoni, C; Boriani, S

    2015-06-01

    Pedicle screw and rod instrumentation has become the preferred technique for performing stabilization and fusion in the surgical treatment of lumbar spine degenerative disease. Rigid fixation leads to high fusion rates but may also contribute to stress shielding and adjacent segment degeneration. Thus, the use of semirigid rods made of polyetheretherketone (PEEK) has been proposed. Although the PEEK rods biomechanical properties, such as anterior load sharing properties, have been shown, there are few clinical studies evaluating their application in the lumbar spine surgical treatment. This study examined a retrospective cohort of patients who underwent posterior lumbar fusion for degenerative disease using PEEK rods, in order to evaluate the clinical and radiological outcomes and the incidence of complications. PMID:25751575

  16. 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).

  17. Effects of solvent exposures on poly(etheretherketone) (PEEK) and PEEK-fiberglass composites

    SciTech Connect

    Whitaker, R.B.; Brown, C.R.; Carlson, R.S.; Trainer, P.D.

    1986-12-15

    Specimens of PEEK and PEEK-fiberglass (FG) were exposed to a number of solvents, and, after removal of the solvents, were tested for changes in weight, tensile strength, and thermal/chemical properties. Solvents tested included: Alconox/water, ethanol, trichloroethylene, ethylene glycol, toluene, Freon TF, silicone oil, and dilute (15%) NaOH and H/sub 2/SO/sub 4/ solutions. Exposures were for five days at temperatures up to 80/sup 0/C. The only significant decreases in tensile strength after solvent exposure occurred with the dilute NaOH-exposed PEEK-FG specimens. Several samples showed minor weight changes. Differential scanning calorimetry showed that the ability of the solvent-exposed PEEK or PEEK-FG recrystallize was not affected, except in concentrated H/sub 2/S/sub 4/ (greater than or equal to65 wt %) solutions. Similarly, infrared (ir) spectroscopic analyses showed no changes in solvent-exposed PEEK or PEEK-FG, except in greater than or equal to85% H/sub 2/SO/sub 4/, where minor changes in the ir spectrum were observed. Examination of the glass transition (Tg) region of concentrated (65%) H/sub 2/SO/sub 4/-exposed PEEK, the dilute NaOH-exposed PEEK-FG, and the dilute H/sub 2/SO/sub 4/-exposed PEEK-FG by thermomechanical and dynamic mechanical analyses showed no significant differences from unexposed controls. Similar results were obtained for alcohol- and trichloroethylene-exposed PEEK specimens. 7 figs., 9 tabs.

  18. 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

  19. Dual resin bonded joints in polyetheretherketone (PEEK) matrix composites

    NASA Astrophysics Data System (ADS)

    Zelenak, Steve; Radford, Donald W.; Dean, Michael W.

    1993-04-01

    The paper describes applications of the dual resin (miscible polymer) bonding technique (Smiley, 1989) developed as an alternative to traditional bonding approaches to joining thermoplastic matrix composite subassemblies into structures. In the experiments, the performance of joint geometries, such as those that could be used to assemble large truss structures in space, are investigated using truss joint models consisting of woven carbon fiber/PEEK tubes of about 1 mm wall thickness. Specific process conditions and hand-held hardware used to apply heat and pressure were chosen to simulate a field asembly technique. Results are presented on tube/cruciform double lap shear tests, pinned-pinned tube compression tests, and single lap shear bond tests of joints obtained using the dual resin bonding technique.

  20. Fatigue behavior of carbon fiber reinforced polyetheretherketone (PEEK) laminated composites (III)

    SciTech Connect

    Ma, C.C.M.; Kuo, H.C.; Chang, M.J.; Ong, C.L.; Wu, I.C.; Sheu, M.F.

    1993-12-31

    Fatigue behavior of carbon fiber reinforced polyetheretherketone (PEEK) laminated composite [O/({+-}45){sub 4}/90]{sub S} was investigated. The [0/({+-}45){sub 4}/90]{sub S} AS-4/PEEK composite laminate under static loading and tension-tension fatigue loading tests were conducted at various levels of stress amplitude to study the effect of stress amplitude on the fatigue life. The experimental fatigue life data under different stress amplitude tests were estimated by median rank order-statistic cumulative-distribution function. Then, the fitting curves of estimated data were analyzed by utilizing the Weibull distribution function. The S-N curves for a series of cyclic loading at different survival probability were also presented and the damage behavior after fatigue loading test was also investigated by optical microscopy.

  1. Crystalline morphology of the matrix of PEEK-carbon fiber aromatic polymer composites. I. Assessment of crystallinity. [Polyetheretherketone

    SciTech Connect

    Blundell, D.J.; Chalmers, J.M.; Mackenzie, M.W.; Gaskin, W.F.

    1985-07-01

    The crystallinity of the polyetheretherketone (PEEK) matrix polymer in the Aromatic Polymer Composite APC-2 has been estimated using a combination of techniques based on wide angle x-ray diffraction and infrared reflection spectroscopy. Crystallinity varies systematically with cooling rate and annealing time over the range 20 to 40%. The occurrence of oriented crystal growth of the PEEK relative to the carbon fiber can be monitored by x-ray diffraction. 8 references, 10 figures, 1 table.

  2. 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.

  3. 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.

  4. The Taylor Impact and Large Strain Response of Poly(Ether-Etherketone) (PEEK)

    NASA Astrophysics Data System (ADS)

    Rae, Philip J.; Brown, Eric N.

    2006-07-01

    Taylor impacts experiments were conducted on PEEK at velocities between 150 & 360 m s-1. The material was found to respond in a ductile manner and exhibit a color change later found to be associated with large compressive strains in PEEK, irrespective of strain-rate. No changes in molecular weight were detected as a result of high-strain rate or large strain deformation. Melting has been shown not to be responsible for the ductile deformation and limited tearing response of PEEK subject to Taylor impact.

  5. 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

  6. The Effect of the PEEK Cage on the Cervical Lordosis in Patients Undergoing Anterior Cervical Discectomy

    PubMed Central

    Gulsen, Salih

    2015-01-01

    BACKGROUND: Loss of cervical lordosis is a significant factor in the development of degeneration of the spine with aging. This degenerative changings of the cervical spine would cause pressure effect on the cervical root and/or medulla spinalis. AIM: Our goal is to understand the effect of the PEEK cage on cervical lordosis in the early postoperative period. Also, to interpret the effects of one- level, two- level, three-level and four- level disc pathologies on cervical lordosis. MATERIAL AND METHODS: We retrospectively investigated our archive, and we selected thirty-four patients undergoing anterior cervical discectomy and fusion with PEEK cage filled with demineralized bone matrix (ACDFP). RESULTS: We determined that ACDFP provides improvement in the cervical lordosis angle in both groups. Also, we found statistically significant difference between group 1 and 2 regarding causes of radiculomyelopathy statistically. CONCLUSION: We achieved better cervical lordotic angles at the postoperative period by implanting one-level, two-level, three-level or four-level PEEK cage filled with demineralized bone matrix. Also, the causes of cervical root and or medulla spinalis impingement were different in group1 and 2. While extruded cervical disc impingement was the first pathology in group 1, osteophyte formation was the first pathology in group 2. PMID:27275224

  7. 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.

  8. Surface Damage Characteristics and Specific Wear Rates of a New Continuous Carbon Fiber (CF) / Polyetheretherketone (PEEK) Composite under Sliding and Rolling Contact Conditions

    NASA Astrophysics Data System (ADS)

    Almajid, Abdulhakim; Friedrich, Klaus; Floeck, Joachim; Burkhart, Thomas

    2011-06-01

    The surface damage characteristics of a continuous carbon fiber reinforced composite, having a polyetheretherketone (PEEK) matrix, were investigated under sliding and rolling contact. The corresponding mechanisms were studied by the use of scanning electron microscopy (SEM) in three different fiber orientations, namely: Paralllel direction to the fibers, AntiParallel direction to the fibers, and Normal direction to the fibers. All wear tests were conducted against smooth steel surfaces for both contact conditions. Mechanical properties under tension, compression, and shear were investigated for the material at two different temperature levels, i.e. room temperature and 150 °C. The composite material under normal fiber orientation has the lowest specific wear rate in case of rolling wear while the parallel orientation has the lowest specific wear rate under sliding wear conditions. Both results were compared to wear data of the neat PEEK matrix.

  9. [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

    Antecedentes: la descompresión y artrodesis con auto-injerto es el patrón de referencia para el tratamiento del conducto cervical estrecho. El uso de cajas de PEEK polímero no reabsorbible, con elasticidad similar al hueso, radiolúcido, y mismo grado de fusión reduce la morbilidad. aterial y métodos: estudio de serie de casos, prospectivo, longitudinal, de intervención deliberada, evaluación en grupol antes y después, seguimiento a dos años. Discoidectomía y colocación de caja de PEEK con injerto autólogo. Se evaluaron artrodesis, lordosis cervical, altura del espacio intervertebral, dolor mediante escala visual análoga, índice de discapacidad cervical, tiempo quirúrgico, sangrado transoperatorio, estancia intrahospitalaria y complicaciones. Análisis estadístico con t de Student, Wilcoxon y exacta de Fisher. Resultados: de 17 pacientes estudiados, 9 (53%) eran del sexo femenino. La edad promedio 62 años. Sangrado promedio de 187 mL. El nivel más afectado fue C5-C6, C6-C7 en cinco pacientes. Se encontró fusión al 100% sin hundimiento ni migración de la caja, altura del espacio conservada, pero no se conservó la lordosis segmentaria. Mejoría clínica en todos los pacientes, y del índice de discapacidad. Conclusión: la disminución de los síntomas, la conservación de la altura del espacio anterior y posterior, la no conservación de la lordosis segmentaria y la fusión con caja de PEEK fueron congruentes con lo reportado en la bibliografía. Se sugiere utilizar la placa anterior para mantener la lordosis cervical. El índice de fusión encontrado fue de 100%, con disminución de los síntomas de dolor y discapacidad. Pérdida de lordosis cervical global.

  10. 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.

  11. 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. PMID:27612794

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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. PMID:26824216

  19. PEEK cages as a potential alternative in the treatment of cervical spondylodiscitis: a preliminary report on a patient series

    PubMed Central

    Walter, Jan; Kuhn, Susanne Antje; Reichart, Rupert; Kalff, Rolf

    2010-01-01

    The surgical management of cervical spondylodiscitis consists of the resection of the affected disc, the decompression of the cervical spinal cord, followed by the stabilization using an autologous bone graft or a titanium implant combined with a ventral plate fixation. Until now, there were no studies about the practicability and putative safety of PEEK cages in cervical spine infection. Now, we present the history of five patients suffering from neurological deficits and septicemia caused by mono- or bisegmental pyogenic cervical discitis and intraspinal abscess without severe bone destruction. Patients were treated surgically by discectomy, decompression, and ventral spondylodesis. The disc was replaced by a PEEK cage without additional fixation. Progressive bony fusion and complete regression of the inflammatory changes was demonstrated 7–8 months later by a computer assisted tomography and contrast enhanced magnetic resonance imaging, respectively. The vertebral alignment changed minimally; the cages developed only a slight average subsidence. The clinical symptoms improved in all patients significantly. Neck pain or instability was never observed. Nevertheless, prospective investigations of a larger patient series are mandatory. We suppose that the use of PEEK cages represents a potential and safe alternative in the treatment of cervical spondylodiscitis in selected patients. PMID:20069319

  20. 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. PMID:25098826

  1. 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

  2. The Taylor impact and high strain-rate response of poly(chlorotrifluoroethylene) PCTFE, poly(ether-etherketone) PEEK and Kel-F 800

    NASA Astrophysics Data System (ADS)

    Rae, Philip

    2005-07-01

    The mechanical properties of PCTFE, PEEK and Kel-F 800 have been investigated over a range of temperatures using both the Taylor impact geometry and Hopkinson bars. PCTFE and PEEK are both industrially important polymers. Kel-F 800 (comprising 75wt% PCTFE and 25wt% poly(vinylidene fluoride) PVDF) was a 3M product that is still used as a binder material in polymer bonded explosives. Compression and tensile Hopkinson bars have been used to generate stress vs. strain data over a range of temperatures for each polymer. Additionally, quasi-static tension and compression data has been collected with respect to strain-rate and temperature for comparison. The Taylor impact geometry has been used to study the ballistic response. High-speed photography was used to quantify sample deformation as a function of time. In each material, a transition velocity is identified between a ductile plastic response involving sample bulging and a brittle response initiated by cracking. Post-shot microscopy has been undertaken to elucidate failure mechanisms.

  3. 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

  4. Laser surface modification of PEEK

    NASA Astrophysics Data System (ADS)

    Riveiro, A.; Soto, R.; Comesaña, R.; Boutinguiza, M.; del Val, J.; Quintero, F.; Lusquiños, F.; Pou, J.

    2012-09-01

    Polyether-ether-ketone (PEEK) is a synthetic thermoplastic polymer with excellent mechanical and chemical properties, which make it attractive for the field of reconstructive surgery. Nevertheless, this material has a poor interfacial biocompatibility due to its large chemical stability which induces poor adhesive bonding properties. The possibilities of enhancing the PEEK adhesive properties by laser treatments have been explored in the past. This paper presents a systematic approach to discern the role of laser irradiation wavelength on the surface modification of PEEK under three laser wavelengths (λ = 1064, 532, and 355 nm) with the aim to determine the most adequate processing conditions to increase the roughness and wettability, the main parameters affecting cell adhesion characteristics of implants. Overall results show that the ultraviolet (λ = 355 nm) laser radiation is the most suitable one to enhance surface wettability of PEEK.

  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. 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.

  7. Comparison of long terms follow up results in patients with cervical disk disease treated with anterior PEEK cage implantation and without it in Rasoul Akram Hospital

    PubMed Central

    Mollahoseini, Reza; Khajoo, Ashkan; Motiei, Mir Abolfazl

    2012-01-01

    Background Anterior interbody fusion of the cervical spine have become the gold standard for treating spinal diseases, hence the aim of this study was to compare long term follow up results in patients with cervical disk disease treated with anterior PEEK cage implantation and without it in anterior approach. Methods Retrospectively 63 patients with known cervical discogenic disorders who went under surgery with and without cage implantation were enrolled. The neurological examination and neurologic function were assessed by using the Japanese Orthopedic Association (JOA) scoring system and neurological cervical spine scale (NCSS) before and 8 years after surgery in each patient and at the end all complications were recorded. Results In the first group, there were 15 males and 14 females (mean age: 49±10 years) and in the second group there were 27 male and 7 female (mean age: 47±9 years). The NCSS score was significantly different between two groups after surgery (p = 0.035) but there was no significant difference before surgery (p = 0.163). No statistical significance difference was also observed in JOA score and complications before and after procedure, but JOA post surgery score between two groups had significant difference (p = 0.047). Conclusion In conclusion, present study showed that PEEK cage implantation is a highly useful alternative to the conventional treatment methods. PMID:23482426

  8. 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

  9. Impact Damage In Carbon/Epoxy And Carbon/PEEK Composites

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    Report describes results of drop-weight impact testing of specimens of carbon-fiber/epoxy and carbon-fiber/polyetheretherketone (PEEK) composite materials. Panels made of these materials assembled into lightweight, strong, stiff structures useful in automobiles, aircraft, sporting goods, and many other products. PEEK specimens showed less delamination than epoxy specimens at given impact energy.

  10. 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

  11. Enhancement of adhesion on polyether etherketone (PEEK) by excimer laser treatments

    SciTech Connect

    Sadras, B.; Laurens, P.; Decobert, F.; Arefi, F.; Amouroux, J.

    1996-12-31

    Due to its important chemical stability, polyether-etherketone (PEEK) thermoplastic presents poor adhesive bonding properties. The possibilities of enhancing the PEEK adhesive properties by excimer laser pretreatments are investigated. Surface modifications are characterized, depending on the experimental working conditions, using SEM, profilometry, XPS, wettability and mechanical tests. Lap shear strength values show that excimer laser irradiation improve PEEK adhesion bonding properties for all treatment conditions (energy, atmosphere).

  12. 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

  13. 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.

  14. Polyetheretherketone/poly (glycolic acid) blend scaffolds with biodegradable properties.

    PubMed

    Shuai, Chenying; Wu, Ping; Zhong, Yancheng; Feng, Pei; Gao, Chengde; Huang, Wei; Zhou, Zhiyang; Chen, Li; Shuai, Cijun

    2016-10-01

    Polyetheretherketone (PEEK) is widely applied in tissue engineering due to its good biocompatibility and mechanical properties. However, the slow degradation rate limits its further application. In this study, PEEK blended with plyglycolicacid (PGA) was used to fabricate porous scaffolds via selective laser sintering. The results demonstrated that the blend scaffolds could gradually degrade, and the degradation rate was able to regulate by tailoring the PGA content. Moreover, the scaffolds maintained good biocompatibility and suitable mechanical properties. These were explained as follows: PGA on the surface layer of the scaffolds might degrade first owing to its exposure to the ambient medium. The degraded PGA left much space, which could promote cell attachment and proliferation. Meanwhile, the slow degradation of PEEK was beneficial to sustaining the scaffolds' strength and stable structure. PMID:27398735

  15. 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.

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

    PubMed Central

    2013-01-01

    Background 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. Methods/Design 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. Discussion 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

  17. Wide-angle X-ray scattering study of heat-treated PEEK and PEEK composite

    NASA Technical Reports Server (NTRS)

    Cebe, Peggy; Lowry, Lynn; Chung, Shirley Y.; Yavrouian, Andre; Gupta, Amitava

    1987-01-01

    Samples of poly(etheretherketone) (PEEK) neat resin and APC-2 carbon fiber composite were subjected to various heat treatments, and the effect of quenching and annealing treatments was studied by wide-angle X-ray scattering. It is found that high-temperature treatments may introduce disorder into neat resin and composite PEEK when followed by rapid cooling. The disorder is metastable and can revert to ordered state when the material is heated above its glass transition temperature and then cooled slowly. The disorder may result from residual thermal stresses.

  18. 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.

  19. 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.

  20. Biomechanical and bioactivity concepts of polyetheretherketone composites for use in orthopedic implants-a review.

    PubMed

    Abdullah, Mohamed Ruslan; Goharian, Amirhossein; Abdul Kadir, Mohammed Rafiq; Wahit, Mat Uzir

    2015-11-01

    The use of polyetheretherketone (PEEK) composites in the trauma plating system, total replacement implants, and tissue scaffolds has found great interest among researchers. In recent years (2008 afterward), this type of composites has been examined for suitability as substitute material over stainless steel, titanium alloys, ultra high molecular weight polyethylene, or even biodegradable materials in orthopedic implant applications. Biomechanical and bioactivity concepts were contemplated for the development of PEEK orthopedic implants and a few primary clinical studies reported the clinical outcomes of PEEK-based orthopedic implants. This study aims to review and discuss the recent concepts and contribute further concepts in terms of biomechanical and bioactivity challenges for the development of PEEK and PEEK composites in orthopedic implants.

  1. 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

  2. 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.

  3. Mechanical and thermal expansion properties of glass fibers reinforced PEEK composites at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Chu, X. X.; Wu, Z. X.; Huang, R. J.; Zhou, Y.; Li, L. F.

    2010-02-01

    Polyetheretherketone (PEEK) has been widely used as matrix material for high performance composites. In this work, 30% chopped glass fibers reinforced PEEK composites were prepared by injection molding, and then the tensile, flexural and impact properties were tested at different temperatures. The modulus, strength and specific elongation of glass fibers reinforced PEEK at room temperature, 77 K and 20 K have been compared. And the fracture morphologies of different samples were investigated by scanning electron microscopy (SEM). The results showed a dependence of mechanical properties of glass fibers reinforced PEEK composites on temperature. The coefficient of thermal expansion of unfilled PEEK and glass fibers reinforced PEEK were also investigated from 77 K to room temperature. The results indicated that the thermal expansion coefficient (CTE) of PEEK matrix was nearly a constant in this temperature region, and it can be significantly decreased by adding glass fibers.

  4. 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

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

    PubMed

    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

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

    PubMed

    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.

  7. 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

  8. Surface topography and wetting modifications of PEEK for implant applications.

    PubMed

    Akkan, Cagri Kaan; Hammadeh, Mohammed Eid; May, Alexander; Park, Hai-Woong; Abdul-Khaliq, Hashim; Strunskus, Thomas; Aktas, Oral Cenk

    2014-09-01

    Polyetheretherketone (PEEK) is considered as a substitute for metallic implant materials due to its extremely low elastic modulus (3-4 GPa). Despite its good mechanical properties, PEEK exhibits a slow integration with the bone tissue due to its relatively inert surface and low biocompatibility. We introduced a dual modification method, which combines the laser and plasma surface treatments to achieve hierarchically patterned PEEK surfaces. While the plasma treatment leads to nanotopography, the laser treatment induces microstructures over the PEEK surface. On the other hand, plasma and laser treatments induce inhomogeneity in the surface chemistry in addition to the tailored surface topography. Therefore, we coated the structured PEEK surfaces with a thin alumina layer by pulsed laser deposition (PLD) to get identical surface chemistry on each substrate. Such alumina-coated PEEK surfaces are used as a model to investigate the effect of the surface topography on the wetting independent from the surface chemistry. Prepared surfaces bring advantages of enhanced wetting, multiscaled topography, proven biocompatibility (alumina layer), and low elastic modulus (PEEK as substrate), which together may trigger the use of PEEK in bone and other implant applications.

  9. Covalent Grafting of the RGD-Peptide onto Polyetheretherketone Surfaces via Schiff Base Formation

    PubMed Central

    Becker, Marc; Lorenz, Steffen; Strand, Dennis; Vahl, Christian-Friedrich; Gabriel, Matthias

    2013-01-01

    In recent years, the synthetic polymer polyetheretherketone (PEEK) has increasingly been used in a number of orthopedic implementations, due to its excellent mechanical properties, bioinertness, and chemical resistance. For in vivo applications, the surface of PEEK, which does not naturally support cell adhesion, has to be modified to improve tissue integration. In the present work we demonstrate a novel wet-chemical modification of PEEK to modify the surface, enabling the covalent grafting of the cell-adhesive RGD-peptide. Modification of the polymer surface was achieved via Schiff base formation using an aliphatic diamine and subsequent crosslinker-mediated immobilization of the peptide. In cell culture experiments with primary osteoblasts it was shown that the RGD-modified PEEK not only significantly promoted cellular adhesion but also strongly enhanced the proliferation of osteoblasts on the modified polymer surface. PMID:24228010

  10. Covalent grafting of the RGD-peptide onto polyetheretherketone surfaces via Schiff base formation.

    PubMed

    Becker, Marc; Lorenz, Steffen; Strand, Dennis; Vahl, Christian-Friedrich; Gabriel, Matthias

    2013-01-01

    In recent years, the synthetic polymer polyetheretherketone (PEEK) has increasingly been used in a number of orthopedic implementations, due to its excellent mechanical properties, bioinertness, and chemical resistance. For in vivo applications, the surface of PEEK, which does not naturally support cell adhesion, has to be modified to improve tissue integration. In the present work we demonstrate a novel wet-chemical modification of PEEK to modify the surface, enabling the covalent grafting of the cell-adhesive RGD-peptide. Modification of the polymer surface was achieved via Schiff base formation using an aliphatic diamine and subsequent crosslinker-mediated immobilization of the peptide. In cell culture experiments with primary osteoblasts it was shown that the RGD-modified PEEK not only significantly promoted cellular adhesion but also strongly enhanced the proliferation of osteoblasts on the modified polymer surface. PMID:24228010

  11. Effect of surface pretreatments on resin composite bonding to PEEK.

    PubMed

    Silthampitag, Patcharawan; Chaijareenont, Pisaisit; Tattakorn, Kittipong; Banjongprasert, Chaiyasit; Takahashi, Hidekazu; Arksornnukit, Mansuang

    2016-01-01

    This study evaluated the effect of surface pretreatments on resin composite bonding to polyetheretherketone (PEEK). Four groups of surface pretreatment (no pretreatment, etched with 98% sulfuric acid, etched with piranha solution and sandblasting with 50 µm alumina) were performed on PEEK. Surface roughness, Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were examined. Shear bond strength (SBS) and interface characteristics were also evaluated after the specimens were bonded with resin materials. Two-way ANOVA analysis revealed significance on two main effects and interactions. Tukey's multiple comparisons test showed that the SBS of resin composite on PEEK were the highest in the group etched with 98% sulfuric acid and bonded with Heliobond(®) (p<0.05). All pretreatments produced similar spectra of FTIR patterns. SEM demonstrated porosities and pitting from chemical etching, which suggested a significant influence on the adhesion between PEEK and resin materials. PMID:27477234

  12. 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.

  13. Preparation, characterization, cellular response and in vivo osseointegration of polyetheretherketone/nano-hydroxyapatite/carbon fiber ternary biocomposite.

    PubMed

    Deng, Yi; Zhou, Ping; Liu, Xiaochen; Wang, Lixin; Xiong, Xiaoling; Tang, Zhihui; Wei, Jie; Wei, Shicheng

    2015-12-01

    As FDA-approved implantable material, polyetheretherketone (PEEK) is becoming a prime candidate to replace traditional surgical metallic implants made of titanium (Ti) and its alloys, since it has a lower elastic modulus than Ti. The bioinertness and defective osteointegration of PEEK, however, limit its clinical adoption as load-bearing dental/orthopedic material. The present work aimed at developing a PEEK bioactive ternary composite, polyetheretherketone/nano-hydroxyapatite/carbon fiber (PEEK/n-HA/CF), and evaluating it as a potential bone-repairing material by assessment of growth and differentiation of osteoblast-like MG63 cells and by estimation of osteointegration in vivo. Our results indicated that the adhesion, proliferation and osteogenic differentiation of cells, as well as the mechanical properties were greatly promoted for the PEEK/n-HA/CF biocomposite compared with pure PEEK matrix. More importantly, the ternary composite implant boosted in vivo bioactivity and osseointegration in canine tooth defect model. Thus, the PEEK/n-HA/CF ternary biocomposite with enhanced mechanics and biological performances hold great potential as bioactive implant material in dental and orthopedic applications. PMID:26363268

  14. Preparation, characterization, cellular response and in vivo osseointegration of polyetheretherketone/nano-hydroxyapatite/carbon fiber ternary biocomposite.

    PubMed

    Deng, Yi; Zhou, Ping; Liu, Xiaochen; Wang, Lixin; Xiong, Xiaoling; Tang, Zhihui; Wei, Jie; Wei, Shicheng

    2015-12-01

    As FDA-approved implantable material, polyetheretherketone (PEEK) is becoming a prime candidate to replace traditional surgical metallic implants made of titanium (Ti) and its alloys, since it has a lower elastic modulus than Ti. The bioinertness and defective osteointegration of PEEK, however, limit its clinical adoption as load-bearing dental/orthopedic material. The present work aimed at developing a PEEK bioactive ternary composite, polyetheretherketone/nano-hydroxyapatite/carbon fiber (PEEK/n-HA/CF), and evaluating it as a potential bone-repairing material by assessment of growth and differentiation of osteoblast-like MG63 cells and by estimation of osteointegration in vivo. Our results indicated that the adhesion, proliferation and osteogenic differentiation of cells, as well as the mechanical properties were greatly promoted for the PEEK/n-HA/CF biocomposite compared with pure PEEK matrix. More importantly, the ternary composite implant boosted in vivo bioactivity and osseointegration in canine tooth defect model. Thus, the PEEK/n-HA/CF ternary biocomposite with enhanced mechanics and biological performances hold great potential as bioactive implant material in dental and orthopedic applications.

  15. 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. PMID:26117784

  16. [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.

  17. 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

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

    PubMed

    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

  19. 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

  20. Low-temperature thermal conductivity of composites: Alumina fiber/epoxy and alumina fiber/PEEK

    SciTech Connect

    Rule, D.L.; Sparks, L.L.

    1989-05-01

    The thermal conductivities of poly-ether-ether-ketone (PEEK), of alumina fiber in a matrix of PEEK, and of alumina fiber in a matrix of epoxy, were determined along with the effects of fiber orientation and thermal cycling. Thermal conductivity was measured over the temperature range of 4.2 to 310 K using a steady-state apparatus. Data are presented and discussed relative to specimen characteristics. It appears that, after accounting for different fiber fractions in the specimens, the thermal conductivity of the PEEK composite material is less than that of the epoxy composite material in particular temperature ranges.

  1. 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

  2. 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.

  3. Fracture characteristics of PEEK at various stress triaxialities.

    PubMed

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

    2016-12-01

    Polyether-ether-ketone (PEEK) is an alternative to metal alloys in orthopaedic applications. It gives significant advantages including excellent mechanical properties and non-toxicity. In this work, a set of specimens with different notched radii were selected to examine the effect of triaxial state of stress on the fracture behavior of PEEK. Fractographic analysis via scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) further elucidated the fracture micromechanisms. Distinct fracture patterns were identified under different stress triaxialities. In addition, the microstructural inclusion properties in PEEK specimen such as inclusion size and chemical composition were analysed and determined. Finite element simulations were carried out to evaluate the correlation of observed fracture characteristics with different stress triaxialities. PMID:27498427

  4. 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.

  5. 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.

  6. 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.

  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. PMID:25833994

  8. Effects of the mold temperature on the mechanical properties and crystallinity of hydroxyapatite whisker-reinforced polyetheretherketone scaffolds.

    PubMed

    Conrad, Timothy L; Jaekel, David J; Kurtz, Steven M; Roeder, Ryan K

    2013-05-01

    Porous and bioactive polyetheretherketone (PEEK) scaffolds have potential to replace metallic scaffolds for biologic fixation of permanent implants adjacent to trabecular bone, such as interbody spinal fusion devices. The objective of this study was to investigate the effects of the mold temperature and PEEK powder on the mechanical properties and crystallinity of hydroxyapatite (HA) whisker-reinforced PEEK scaffolds prepared using compression molding and porogen leaching. Scaffolds were prepared at mold temperatures ranging 340-390°C with a 50 or 10 μm PEEK powder, 75 vol% porosity, and 20 vol% HA whiskers. Scaffold mechanical properties were evaluated in unconfined, uniaxial compression and the PEEK matrix crystallinity was measured using specular reflectance Fourier transform infrared spectroscopy. Increased mold temperature resulted in increased compressive modulus, yield strength, and yield strain, reaching a plateau at ~370°C. HA reinforcements were observed to be segregated between PEEK particles, which inhibited PEEK particle coalescence during compression molding at temperatures less than 365°C but also ensured that bioactive HA reinforcements were exposed on scaffold strut surfaces. Increased mold temperature also resulted in decreased PEEK crystallinity, particularly for scaffolds molded at greater than 375°C. The PEEK powder size exhibited relatively minor effects on the scaffold mechanical properties and PEEK crystallinity. Therefore, the results of this study suggested that HA-reinforced PEEK scaffolds should be compression molded at 370-375°C. The apparent compressive modulus, yield strength, and yield strain for scaffolds molded at 370-375°C was 75-92 MPa, 2.0-2.2 MPa, and 2.5-3.6%, respectively, which was within the range exhibited by human vertebral trabecular bone.

  9. 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

  10. Preparation, characterization, in vitro bioactivity, and cellular responses to a polyetheretherketone bioactive composite containing nanocalcium silicate for bone repair.

    PubMed

    Ma, Rui; Tang, Songchao; Tan, Honglue; Qian, Jun; Lin, Wentao; Wang, Yugang; Liu, Changsheng; Wei, Jie; Tang, Tingting

    2014-08-13

    In this study, a nanocalcium silicate (n-CS)/polyetheretherketone (PEEK) bioactive composite was prepared using a process of compounding and injection-molding. The mechanical properties, hydrophilicity, and in vitro bioactivity of the composite, as well as the cellular responses of MC3T3-E1 cells (attachment, proliferation, spreading, and differentiation) to the composite, were investigated. The results showed that the mechanical properties and hydrophilicity of the composites were significantly improved by the addition of n-CS to PEEK. In addition, an apatite-layer formed on the composite surface after immersion in simulated body fluid (SBF) for 7 days. In cell culture tests, the results revealed that the n-CS/PEEK composite significantly promoted cell attachment, proliferation, and spreading compared with PEEK or ultrahigh molecular weight polyethylene (UHMWPE). Moreover, cells grown on the composite exhibited higher alkaline phosphatase (ALP) activity, more calcium nodule-formation, and higher expression levels of osteogenic differentiation-related genes than cells grown on PEEK or UHMWPE. These results indicated that the incorporation of n-CS to PEEK could greatly improve the bioactivity and biocompatibility of the composite. Thus, the n-CS/PEEK composite may be a promising bone repair material for use in orthopedic clinics.

  11. 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. PMID:27040195

  12. Preparation, characterization, in vitro bioactivity, and cellular responses to a polyetheretherketone bioactive composite containing nanocalcium silicate for bone repair.

    PubMed

    Ma, Rui; Tang, Songchao; Tan, Honglue; Qian, Jun; Lin, Wentao; Wang, Yugang; Liu, Changsheng; Wei, Jie; Tang, Tingting

    2014-08-13

    In this study, a nanocalcium silicate (n-CS)/polyetheretherketone (PEEK) bioactive composite was prepared using a process of compounding and injection-molding. The mechanical properties, hydrophilicity, and in vitro bioactivity of the composite, as well as the cellular responses of MC3T3-E1 cells (attachment, proliferation, spreading, and differentiation) to the composite, were investigated. The results showed that the mechanical properties and hydrophilicity of the composites were significantly improved by the addition of n-CS to PEEK. In addition, an apatite-layer formed on the composite surface after immersion in simulated body fluid (SBF) for 7 days. In cell culture tests, the results revealed that the n-CS/PEEK composite significantly promoted cell attachment, proliferation, and spreading compared with PEEK or ultrahigh molecular weight polyethylene (UHMWPE). Moreover, cells grown on the composite exhibited higher alkaline phosphatase (ALP) activity, more calcium nodule-formation, and higher expression levels of osteogenic differentiation-related genes than cells grown on PEEK or UHMWPE. These results indicated that the incorporation of n-CS to PEEK could greatly improve the bioactivity and biocompatibility of the composite. Thus, the n-CS/PEEK composite may be a promising bone repair material for use in orthopedic clinics. PMID:25013988

  13. 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. PMID:15020136

  14. 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.

  15. Characterization of New PEEK/HA Composites with 3D HA Network Fabricated by Extrusion Freeforming.

    PubMed

    Vaezi, Mohammad; Black, Cameron; Gibbs, David M R; Oreffo, Richard O C; Brady, Mark; Moshrefi-Torbati, Mohamed; Yang, Shoufeng

    2016-05-26

    Addition of bioactive materials such as calcium phosphates or Bioglass, and incorporation of porosity into polyetheretherketone (PEEK) has been identified as an effective approach to improve bone-implant interfaces and osseointegration of PEEK-based devices. In this paper, a novel production technique based on the extrusion freeforming method is proposed that yields a bioactive PEEK/hydroxyapatite (PEEK/HA) composite with a unique configuration in which the bioactive phase (i.e., HA) distribution is computer-controlled within a PEEK matrix. The 100% interconnectivity of the HA network in the biocomposite confers an advantage over alternative forms of other microstructural configurations. Moreover, the technique can be employed to produce porous PEEK structures with controlled pore size and distribution, facilitating greater cellular infiltration and biological integration of PEEK composites within patient tissue. The results of unconfined, uniaxial compressive tests on these new PEEK/HA biocomposites with 40% HA under both static and cyclic mode were promising, showing the composites possess yield and compressive strength within the range of human cortical bone suitable for load bearing applications. In addition, preliminary evidence supporting initial biological safety of the new technique developed is demonstrated in this paper. Sufficient cell attachment, sustained viability in contact with the sample over a seven-day period, evidence of cell bridging and matrix deposition all confirmed excellent biocompatibility.

  16. Characterization of New PEEK/HA Composites with 3D HA Network Fabricated by Extrusion Freeforming.

    PubMed

    Vaezi, Mohammad; Black, Cameron; Gibbs, David M R; Oreffo, Richard O C; Brady, Mark; Moshrefi-Torbati, Mohamed; Yang, Shoufeng

    2016-01-01

    Addition of bioactive materials such as calcium phosphates or Bioglass, and incorporation of porosity into polyetheretherketone (PEEK) has been identified as an effective approach to improve bone-implant interfaces and osseointegration of PEEK-based devices. In this paper, a novel production technique based on the extrusion freeforming method is proposed that yields a bioactive PEEK/hydroxyapatite (PEEK/HA) composite with a unique configuration in which the bioactive phase (i.e., HA) distribution is computer-controlled within a PEEK matrix. The 100% interconnectivity of the HA network in the biocomposite confers an advantage over alternative forms of other microstructural configurations. Moreover, the technique can be employed to produce porous PEEK structures with controlled pore size and distribution, facilitating greater cellular infiltration and biological integration of PEEK composites within patient tissue. The results of unconfined, uniaxial compressive tests on these new PEEK/HA biocomposites with 40% HA under both static and cyclic mode were promising, showing the composites possess yield and compressive strength within the range of human cortical bone suitable for load bearing applications. In addition, preliminary evidence supporting initial biological safety of the new technique developed is demonstrated in this paper. Sufficient cell attachment, sustained viability in contact with the sample over a seven-day period, evidence of cell bridging and matrix deposition all confirmed excellent biocompatibility. PMID:27240326

  17. 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. PMID:27434650

  18. Mechanical properties of alumina-PEEK unidirectional composite - Compression, shear, and tension

    NASA Technical Reports Server (NTRS)

    Kriz, R. D.; Mccolskey, J. D.

    1990-01-01

    An Al2O3 (alumina)-fiber composite with high strain to failure was fabricated with a thermal plastic PEEK (poly-ether-ether-ketone). The Al2O3-PEEK composite shows a marked improvement over thermally setting composite in that it absorbs 150 percent more elastic-strain energy at 76 K than at room temperature. This increase in fracture toughness at low temperatures can provide improved fatigue performance for thermal isolation straps at low temperature. Other mechanical property results suggest improvements for applications where graphite-epoxy materials are presently being used at low temperatures and where light weight is not a critical issue.

  19. Influence of the temperature on the tribological behaviour of PEEK composites in vacuum environment

    NASA Astrophysics Data System (ADS)

    Theiler, G.; Gradt, T.

    2008-03-01

    This paper describes tribological experiments carried out with polyetheretherketone (PEEK), filled with carbon fibres and solid lubricants (polytetrafluoroethylene (PTFE), graphite or MoS2), against steel discs. Oscillating sliding tests were performed in high vacuum environment in the temperature range between -40°C and +160°C. Results indicate that MoS2 filled PEEK show the best tribological performance in vacuum. Particularly, in the lower temperature range and at higher loads the friction behaviour is improved by the MoS2 content.

  20. 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. PMID:12895584

  1. 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.

  2. 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

  3. 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. PMID:27524073

  4. 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

  5. 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. PMID:26981285

  6. 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.

  7. Fixation strength of taper connection at head-neck junction in retrieved carbon fiber-reinforced PEEK hip stems.

    PubMed

    Nakahara, Ichiro; Takao, Masaki; Bandoh, Shunichi; Sugano, Nobuhiko

    2014-12-01

    Carbon fiber-reinforced polyetheretherketone (CFR-PEEK) hip prostheses possess numerous advantages over metal prostheses; however, the security of the taper connection between the CFR-PEEK stem and the modular femoral head in vivo has not been verified. Therefore, we mechanically examined the taper connection of retrieved in vivo loaded CFR-PEEK stems in comparison with in vivo loaded titanium alloy stems. CFR-PEEK and titanium alloy femoral stems with a 12/14 taper trunnion were implanted in ovine hips. A 22-mm ceramic head was intraoperatively impacted to the stem. Retrieved specimens were obtained following weight-bearing conditions for up to 39 postoperative weeks and taper junction pull-off tests were conducted. Postoperative retrieved CFR-PEEK stem pull-off strength was significantly greater than that at time zero. Postoperative retrieved CFR-PEEK stem pull-off strength was also significantly higher than that of postoperative retrieved titanium alloy stem. Microscopic findings of the taper surface revealed no obvious damage in the retrieved CFR-PEEK stems, whereas fretting and corrosion were observed in the retrieved titanium alloy stems. The present findings suggest that the taper connection between the ceramic head and the 12/14 CFR-PEEK stem trunnion is more secure than that between the ceramic head and the titanium alloy trunnion. PMID:25190272

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

    PubMed

    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

  9. Time-dependent mechanical properties of 3-D braided graphite/PEEK composites

    SciTech Connect

    Chu, J.N.; Ko, F.K. ); Song, J.W. )

    1992-07-01

    Poly(ether-ether-ketone) or PEEK, was developed as a high performance engineering material. In this study, 3-D braided AS4 graphite /PEEK (graphite/PEEK) composites were preformed and processed to investigate the combined performance of this new system. These manufactured composites were then characterized, using matrix digestion and wide angle x-ray diffraction, to determine their fiber volume fractions and degrees of crystallinity. After physical characterization, the mechanical response of these composites were evaluated at various temperatures. Experimental results from tensile measurements are compared to a fabric geometry model (FGM). This model predicts tensile strength based upon fiber and matrix properties, fiber volume fraction, and braiding angle. The model 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 graphite/PEEK composites, their stress relaxation and dynamic mechanical properties were evaluated. The dynamic mechanical properties of PEEK composites are compared to short fiber and continuous fiber reinforced PEEK composites to determine the effects of fiber geometry.

  10. 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.

  11. In Vitro and in Vivo Evaluation of Silicate-Coated Polyetheretherketone Fabricated by Electron Beam Evaporation.

    PubMed

    Wen, Jin; Lu, Tao; Wang, Xiao; Xu, Lianyi; Wu, Qianju; Pan, Hongya; Wang, Donghui; Liu, Xuanyong; Jiang, Xinquan

    2016-06-01

    Intrinsic bioinertness severely hampers the application of polyetheretherketone (PEEK), although in the field of dentistry it is considered to be an ideal titanium substitute implanting material. In this study, a bioactive silicate coating was successfully introduced onto PEEK surface by using electron beam evaporation (EBE) technology to improve its bioactivity and osseointegration of PEEK. Through controlling the duration of EBE, the incorporated amounts of silicon (Si) could be exquisitely adjusted to obtain proper biofunctionality, as assessed by cell adhesion, proliferation, osteogenic gene expression, and protein detection. In vivo, the samples were then tested in a femur implantation model to assay osseointegration effects in ovariectomized (OVX) rats. Remarkable enhancement of adhesion, spreading, osteogenesis, and differentiation of bone marrow stem cells (rBMSCs-OVX) were noted on silicate-coated samples. In particular, the group that was processed for 5 min with EBE (EBE-5 min) showed the most improvements in ALP activity and osteogenic-related gene expression compared to the remaining groups. Better osseointegration of the group that was processed for 8 min with EBE (EBE-8 min) was observed in vivo, as indicated by micro-CT test, fluorescent labeling, and histological and histomorphometric analyses. Collectively, the outcomes of the above experiments demonstrate that the present work is a meaningful attempt to promote osseointegration under osteoporotic conditions with only Si element incorporated to PEEK surface by the application of EBE technique. To the best of our knowledge, this work is the first demonstration of tuning the surface properties of PEEK via the adoption of an EBE-fabricated silicate coating to address an osteoporotic problem both in vitro and in vivo.

  12. 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

  13. 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.

  14. An in vitro investigation of bacteria-osteoblast competition on oxygen plasma-modified PEEK.

    PubMed

    Rochford, Edward T J; Subbiahdoss, Guruprakash; Moriarty, T Fintan; Poulsson, Alexandra H C; van der Mei, Henny C; Busscher, Henk J; Richards, R Geoff

    2014-12-01

    Polyetheretherketone (PEEK) films were oxygen plasma treated to increase surface free energy and characterized by X-ray photoelectron microscopy, atomic force microscopy, and water contact angles. A parallel plate flow chamber was used to measure Staphylococcus epidermidis, Staphylococcus aureus, and U-2 OS osteosarcomal cell-line adhesion to the PEEK films in separate monocultures. In addition, bacteria and U-2 OS cells were cocultured to model competition between osteoblasts and contaminating bacteria for the test surfaces. Plasma treatment of the surfaces increased surface oxygen content and decreased the hydrophobicity of the materials, but did not lead to a significant difference in bacterial or U-2 OS cell adhesion in the monocultures. In the S. epidermidis coculture experiments, the U-2 OS cells adhered in greater numbers on the treated surfaces compared to the untreated PEEK and spread to a similar extent. However, in the presence of S. aureus, cell death of the U-2 OS occurred within 10 h on all surfaces. The results of this study suggest that oxygen plasma treatment of PEEK may maintain the ability of osteoblast-like cells to adhere and spread, even in the presence of S. epidermidis contamination, without increasing the risk of preoperative bacterial adhesion. Therefore, oxygen plasma-treated PEEK remains a promising method to improve implant surface free energy for osseointegration.

  15. 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.

  16. Nanomodified Peek Dental Implants: Bioactive Composites and Surface Modification—A Review

    PubMed Central

    Najeeb, Shariq; Khurshid, Zohaib; Matinlinna, Jukka Pekka; Siddiqui, Fahad; Nassani, Mohammad Zakaria; Baroudi, Kusai

    2015-01-01

    Purpose. The aim of this review is to summarize and evaluate the relevant literature regarding the different ways how polyetheretherketone (PEEK) can be modified to overcome its limited bioactivity, and thereby making it suitable as a dental implant material. Study Selection. An electronic literature search was conducted via the PubMed and Google Scholar databases using the keywords “PEEK dental implants,” “nano,” “osseointegration,” “surface treatment,” and “modification.” A total of 16 in vivo and in vitro studies were found suitable to be included in this review. Results. There are many viable methods to increase the bioactivity of PEEK. Most methods focus on increasing the surface roughness, increasing the hydrophilicity and coating osseoconductive materials. Conclusion. There are many ways in which PEEK can be modified at a nanometer level to overcome its limited bioactivity. Melt-blending with bioactive nanoparticles can be used to produce bioactive nanocomposites, while spin-coating, gas plasma etching, electron beam, and plasma-ion immersion implantation can be used to modify the surface of PEEK implants in order to make them more bioactive. However, more animal studies are needed before these implants can be deemed suitable to be used as dental implants. PMID:26495000

  17. 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. PMID:26454136

  18. Autohesion of semi-crystalline PEEK near and under the glass transition temperature

    NASA Astrophysics Data System (ADS)

    Awaja, Firas; Zhang, Shengnan; McKenzie, David R.

    2013-10-01

    Autohesion of semi-crystalline polymers under the glass transition temperature (Tg) is fundamentally difficult due to severe restriction in molecular chain mobility. We demonstrate that enhanced autohesion of semi-crystalline polyetheretherketone (PEEK) at temperatures close or under Tg can be achieved through plasma immersion ion implantation (PIII) treatment. Autohesive bonding strength of PEEK increased linearly with PIII bias voltage up to tenfold compared to untreated controls at 160 °C (Tg +10 °C). At 130 °C (Tg -20 °C), PIII treatment increased bonding strength of PEEK by more than fivefold compared to the untreated control. PIII treated surface exhibited higher surface energy, polar component and oxygen content. A model based on the formation of covalent bonds on the plasma treated PEEK by radicals present at the interface was found to predict the bonding strength above and below Tg. The major mechanism responsible for improved autohesion of PEEK near and under Tg is believed to be free radicals based covalent bonding assisted by an increase of surface wettability and reduction in surface crystal structure as was evidenced by SEM images.

  19. Nanomodified Peek Dental Implants: Bioactive Composites and Surface Modification-A Review.

    PubMed

    Najeeb, Shariq; Khurshid, Zohaib; Matinlinna, Jukka Pekka; Siddiqui, Fahad; Nassani, Mohammad Zakaria; Baroudi, Kusai

    2015-01-01

    Purpose. The aim of this review is to summarize and evaluate the relevant literature regarding the different ways how polyetheretherketone (PEEK) can be modified to overcome its limited bioactivity, and thereby making it suitable as a dental implant material. Study Selection. An electronic literature search was conducted via the PubMed and Google Scholar databases using the keywords "PEEK dental implants," "nano," "osseointegration," "surface treatment," and "modification." A total of 16 in vivo and in vitro studies were found suitable to be included in this review. Results. There are many viable methods to increase the bioactivity of PEEK. Most methods focus on increasing the surface roughness, increasing the hydrophilicity and coating osseoconductive materials. Conclusion. There are many ways in which PEEK can be modified at a nanometer level to overcome its limited bioactivity. Melt-blending with bioactive nanoparticles can be used to produce bioactive nanocomposites, while spin-coating, gas plasma etching, electron beam, and plasma-ion immersion implantation can be used to modify the surface of PEEK implants in order to make them more bioactive. However, more animal studies are needed before these implants can be deemed suitable to be used as dental implants. PMID:26495000

  20. 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

  1. Impact damage of a graphite/PEEK

    SciTech Connect

    Demuts, E.

    1994-12-31

    Low-velocity non-penetrating impact has been applied to graphite polyetheretherketone (AS4/APC-2) laminates in accordance with the USAF guidelines for designing damage tolerant primary structures. The extent of delaminations and dent depths for two lay ups and five thicknesses at room temperature and ambient moisture conditions have been determined. Based on these findings as well as those presented elsewhere it may be concluded that the ``softer`` lay up (40/50/10), up to about 75-ply thickness, is more damage tolerant than the ``harder`` lay up (60/30/10) because within this thickness range the ``softer`` lay up displays smaller dent depths, smaller delaminated areas and higher post-impost compressive strength (PICS). For laminates thicker than 75 plies, the relative situation in delamination extent and PICS is reversed, i.e. the ``harder`` lay up is more damage tolerant than the ``softer`` one. The test data obtained in this experimental investigation provide the amount of initial damage to be assumed for a damage tolerant design of USAF primary structures made out of AS4/APC-2 graphite/PEEK. In addition, 9 these data may serve to validate the predictive capability of appropriate analytic models.

  2. 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.

  3. Effects of LEO Environment on Tensile Properties of PEEK Films

    NASA Astrophysics Data System (ADS)

    Nakamura, Takashi; Nakamura, Hiroshi; Shimamura, Hiroyuki

    2009-01-01

    To clarify the effects of space environment on mechanical properties of polymer, exposure experiments were conducted utilizing the International Space Station Russian Service Module. Poly-ether-ether-ketone (PEEK) films under tensile stress were exposed to low Earth orbit (LEO) environment, and reference samples were irradiated with atomic oxygen (AO), electron beam (EB), and ultraviolet light (UV) in ground facilities. By comparing the results of flight and ground tests, the degradation behavior and the influential factors in LEO were investigated. The following results were obtained. (1) UV was found to be the harshest factor in LEO on tensile properties, since it decreased elongation to 15% of pristine sample after 46-months exposure. (2) AO in LEO eroded the specimen surface with a cone-like morphology and reduced the thickness; however, it had no significant effect on tensile properties. (3) EB irradiation in LEO had no measurable effects on the material properties.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

    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.

  9. The investigation of the action of fillers by XPS studies of the transfer films of PEEK and its composites containing CuS and CuF2

    NASA Astrophysics Data System (ADS)

    Bahadur, S.; Gong, Deli; Anderegg, J. W.

    1993-01-01

    The wear behavior of polyetheretherketone (PEEK) and CuS-PEEK composite rubbing at 1 m/s speed and 19.6 N load against both the steel and glass disks is examined. While CuS filler decreased considerably the wear rate of PEEK in rubbing against the steel disk, the wear rate of both the filled and untilled materials in rubbing against the glass disk was almost the same. The wear rate of CuF2-PEEK composite sliding against a steel surface was also considerably lower than that of PEEK. The transfer films of the polymer and its composites containing CuS and CuF2 formed against the steel disk surfaces were studied by X-ray photoelectron spectroscopy (XPS). The analysis of the XPS spectra revealed that both CuS and CuF2 decomposed under the rubbing conditions. The analysis at two different depths in the transfer film of CuF2-PEEK revealed that the concentrations of Cu and FeF2 were greater close to the transfer film-counterface interface. However, there was no chemical change detected when unfilled PEEK rubbed against the steel disk surface.

  10. 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

    2016-01-01

    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. PMID:26956660

  11. 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. PMID:26796319

  12. Long-term compressive property durability of carbon fibre-reinforced polyetheretherketone composite in physiological saline.

    PubMed

    Zhang, G; Latour, R A; Kennedy, J M; Del Schutte, H; Friedman, R J

    1996-04-01

    In total hip arthroplasty, concerns such as corrosion and stress shielding associated with stiff metallic femoral components have led to the development of low stiffness advanced fibre-reinforced polymer (FRP) composite femoral components. Carbon fibre-reinforced polyetheretherketone (CF/PEEK) composite material is now one of the primary material systems being considered for composite hip stem development. As a hip stem, a composite material must be able to support a complex state of stress in the in vivo environment without failure. Considering the loading conditions of a hip stem (superimposed compression and bending), and the fact that FRP composites typically possess lower compressive than tensile strength, the compressive behaviour of FRP composites becomes very important for femoral component design. This paper presents an investigation of the long-term durability of 0 degree and 90 degrees compressive strengths of CF/PEEK composite following physiological saline saturation. 0 degree and 90 degrees compressive moduli and Poisson ratio (v12) properties are also reported. Samples were tested following conditioning in physiological saline at 37, 65 and 95 degrees C for time periods from 0 to 5000 h. Dry samples were tested as controls. Results show no significant loss in compressive property values of the saline-saturated or the dry control samples as a function of conditioning time or temperature. PMID:8730962

  13. 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.

  14. 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. PMID:26474500

  15. 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. PMID:26773668

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

    PubMed

    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

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

    PubMed

    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.

  18. 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

  19. 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.

  20. 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. PMID:26492595

  1. The use of PEEK nanorod arrays for the fabrication of nanoporous surfaces under high temperature: SiNx example

    NASA Astrophysics Data System (ADS)

    Martín, Jaime; Martín-González, Marisol

    2012-08-01

    Large area silicon nitride (SiNx) nanoporous surfaces are fabricated using poly(ether-ether-ketone) (PEEK) nanorod arrays as a template. The procedure involves manipulation of nanoporous anodic aluminum oxide (AAO) templates in order to form an ordered array of PEEK nanopillars with high temperature resistant characteristics. In this context, self-ordered AAO templates are infiltrated with PEEK melts via the ``precursor film'' method. Once the melts have been crystallized in the porous structure of AAO, the basis alumina layer is removed, yielding an ordered array of PEEK nanopillars. The resulting structure is a high temperature and chemical resistant polymeric nanomold, which can be utilized in the synthesis of nanoporous materials under aggressive conditions. Such conditions are high temperatures (up to 320 °C), vacuum, or extreme pH. For example, SiNx nanopore arrays have been grown by plasma enhanced chemical vapor deposition at 300 °C, which can be of interest as mold for nanoimprint lithography, due to its hardness and low surface energy. The SiNx nanopore array portrays the same characteristics as the original AAO template: 120 nm diameter pores and an interpore distance of 430 nm. Furthermore, the aspect ratio of the SiNx nanopores can be tuned by selecting an AAO template with appropriate conditions. The use of PEEK as a nanotemplate extends the applicability of polymeric nanopatterns into a temperature regime up to now not accessible and opens up the simple fabrication of novel nanoporous inorganic surfaces.

  2. 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

    2015-01-01

    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. PMID:25435385

  3. 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

    2015-01-01

    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.

  4. Chemical anchoring of lauryl methacrylate-based reversed phase monolith to 1/16″ o.d. polyetheretherketone tubing.

    PubMed

    Shu, Shin; Kobayashi, Hiroharu; Okubo, Masaki; Sabarudin, Akhmad; Butsugan, Michio; Umemura, Tomonari

    2012-06-15

    In this paper, we describe a method for the preparation of easy-to-use reversed-phase monolithic microbore columns. Polyetheretherketone (PEEK) tubing with an outer diameter of 1/16″ and an inner diameter of 1.0 mm was used as a column housing (empty column), and in it lauryl methacrylate (LMA) was copolymerized with ethylene dimethacrylate (EDMA). In order to chemically anchor the polymer monolith to the tube wall, the inner wall surface was pretreated by the following two-step procedure. (1) 50% sulfuric acid was filled into the PEEK tubing and left to stand for 6 h to generate sulfonate groups on the surface. (2) After washing with Milli-Q water, the sulfonated PEEK surface was brought into contact with 1 M glycidyl methacrylate in dichloromethane (or acetone) at 40°C for 4 h to introduce methacryloyl groups via the reaction of sulfonate groups and epoxy groups. Mechanical strength and column efficiency of the resulting monoliths were evaluated through the separation of a series of alkylbenzenes in acetonitrile-water (50:50, v/v) eluent over the flow rate range of 50-750 μL/min (corresponding to 1.7-25.5 mm/s). The poly(LMA-co-EDMA) monolith provided acceptable column efficiency of 2000 theoretical plates/10 cm (HETP value of 50 μm) for amylbenzene (separation factor k=40) and low flow resistance of 0.5 MPa/10 cm at a normal flow rate of 50 μL/min. The methacryloylated PEEK tubing tightly held the monolith, and the monolithic column exhibited good pressure resistance up to 15 MPa, allowing rapid separation at a 15-20 fold higher flow rate than normal. PMID:22560348

  5. 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

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

    PubMed

    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.

  7. 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.

  8. Thermal expansion coefficients of a 30% glass fiber filled PEEK pyrotechnic charge holder

    SciTech Connect

    Donnelly, M.W.; Walters, R.R.; Miller, G.D.

    1985-01-01

    Pyrotechnic actuators use hollow cylindrical ceramic or plastic charge holders to electrically isolate the pyrotechnic charge from the actuator case. In a newly developed actuator, 30% glass fiber filled polyetheretherketone (PEEK) was selected as the charge holder material both for its strength and its forming properties. Because the actuators are exposed to significant temperature variations during storage and flight, a determination of the coefficient of thermal expansion, ..cap alpha.., of the charge holders was required to assure success in this, the first electroexplosive device application of PEEK. Of special interest in this project were the questions of whether ..cap alpha.. depends on the direction (with respect to flow in the mold) or on injection pressure. From the test results, the conclusions are: (1) ..cap alpha.. does depend on direction. Its value in the thickness direction is approximately twice that in either the height or circumferential direction. This is probably because the wall thickness, 0.015'', is less than the average fiber length, 0.100'', and the PEEK is, therefore, not acting as a composite in the t direction. (2) Varying the injection pressure over the range of this study has no detectable effect on ..cap alpha... This charge holder is molded into an Inconel actuator case with ..cap alpha.. = 11.4 ..mu..m/m.C. This relatively close match of ..cap alpha..'s between adjacent materials has resulted in no dimensional problems during manufacturing and environmental testing. 1 fig., 1 tab.

  9. PEEK/SiO2 composites with high thermal stability for electronic applications

    NASA Astrophysics Data System (ADS)

    Goyal, R. K.; Rokade, K. A.; Kapadia, A. S.; Selukar, B. S.; Garnaik, B.

    2013-01-01

    Thermal and mechanical properties of new high performance polymer matrix composites based on poly(etheretherketone) (PEEK) as matrix and crystalline-silica (SiO2) as reinforcement were discussed for application in electronic packaging substrates or printed circuit boards. The content of SiO2 was varied between 0 and 50 wt. %. Scanning electron microscopy showed uniform dispersion of SiO2 particles in the matrix. Thermogravimetry analysis showed significant increase in thermal stability and char yield with increase in SiO2 content in the matrix. Differential scanning calorimetry showed that SiO2 had a heterogeneous nucleating effect on PEEK, leading to an increase in peak temperature of crystallization and onset crystallization temperature of the composites compared to a pure matrix. The microhardness increased approximately 42%. A modified rule of mixtures with a strengthening efficiency factor equal to 0.06 fit the data nicely. The results show that the prepared PEEK/SiO2 composites may have potential applications in electronics.

  10. 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

  11. Processing of amorphous PEEK and amorphous PEEK based composites

    SciTech Connect

    Kenny, J.; D'amore, A.; Nicolais, L.; Iannone, M.; Scatteia, B.; Aeritalia, S.p.A., Naples )

    1989-08-01

    An analysis of the crystallization behavior of amorphous PEEK, its carbon fiber composite, and its relationships with dynamic-mechanical properties of the system measured during and after processing is presented. The effect of the processing conditions, time and temperature, on the quality and on the amount of the crystallinity developed during cold crystallization has been investigated in order to evaluate the processability window of amorphous PEEK and amorphous PEEK based composite above the glass transition temperature and below the melting point. Also, the anomalous behavior of the amorphous matrix, crystallized at low temperatures, has been studied. Multiple melting peaks and changes of the glass transition during crystallization are explained in terms of crystalline morphology and molecular mobility. 20 refs.

  12. 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.

  13. Characterisation of Ni + implanted PEEK, PET and PI

    NASA Astrophysics Data System (ADS)

    Mackova, A.; Bocan, J.; Khaibullin, R. I.; Valeev, V. F.; Slepicka, P.; Sajdl, P.; Svorcik, V.

    2009-05-01

    Polyimide (PI), polyetheretherketone (PEEK) and polyethyleneterephthalate (PET) were implanted with 40 keV Ni+ ions at room temperature at fluences ranging from 1.0 × 1016 to 1.5 × 1017 ions cm-2 and with ion current density varying between 4 and 10 μA cm-2. The depth profiles of the implanted Ni atoms determined by the RBS technique were compared with those predicted by the SRIM and TRIDYN codes. Hydrogen depletion as a function of the ion fluence was determined by the ERDA technique, and the compositional and structural changes of the polymers were characterised by the UV-vis and XPS methods. The implanted profiles differed significantly from those predicted by the SRIM code while the lower fluences were satisfactorily described by the TRIDYN simulation. A significant hydrogen release from the polymer surface layer was observed along with significant changes in the surface layer composition. The UV-vis results indicated an increase in the concentration and conjugation of double bonds.

  14. Nano-hydroxyapatite-coated PEEK implants: a pilot study in rabbit bone.

    PubMed

    Barkarmo, Sargon; Wennerberg, Ann; Hoffman, Maria; Kjellin, Per; Breding, Karin; Handa, Paul; Stenport, Victoria

    2013-02-01

    Osseointegration of surface-modified polyetheretherketone (PEEK) implants was studied in vivo. A total of 18 cylinder-shaped PEEK implants were inserted in the femurs of nine New Zealand rabbits; half were coated with nanocrystalline hydroxyapatite (nanoHA) and half were uncoated controls. Healing time was 6 weeks. Samples were retrieved with the implant and surrounding tissue, processed to cut and ground sections, and analyzed histomorphometrically. The implant surfaces were analyzed with optical interferometry, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). NanoHA-coated PEEK surfaces had lower height deviation (Sa) than controls [mean ± SD: 0.41 μm (± 0.14) vs. 0.96 μm (± 0.28)]. SEM images showed the nanoHA crystals as a thin layer on the polymer surface. XPS analysis of the coated implants showed a Ca/P ratio of 1.67. Histomorphometry indicated that the nanoHA-coated implants had more bone-to-implant contact [16% (± 4.7) vs. 13% (± 9.3)] and more bone area [52% (± 9.5) vs. 45% (± 11.9)]. We found no difference between smooth nanoHA-coated cylinder-shaped PEEK implants and uncoated controls. However, higher mean bone-to-implant contact indicated better osseointegration in the coated implants than in the uncoated controls. The large number of lost implants was interpreted as a lack of primary stability due to implant design.

  15. 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.

  16. Annealing of PEEK, PET and PI implanted with Co ions at high fluencies

    NASA Astrophysics Data System (ADS)

    Mackova, A.; Malinsky, P.; Miksova, R.; Pupikova, H.; Khaibullin, R. I.; Valeev, V. F.; Svorcik, V.; Slepicka, P.

    2013-07-01

    The properties of implanted polymers strongly depend on the implantation ion fluence and on the properties of the implanted atoms. The stability of synthesized nano-structures during further technological steps like annealing is of importance for their possible applications. Polyimide (PI), polyetheretherketone (PEEK), and polyethyleneterephtalate (PET) were implanted with 40 keV Co+ ions at room temperature at fluences ranging from 0.2 × 1016 cm-2 to 1.0 × 1017 cm-2 and annealed at a temperature of 200 °C. The implanted depth profiles of as-implanted and annealed samples, determined by the RBS method, were compared with the results of SRIM 2012 simulations. The structural and compositional changes of the implanted and subsequently annealed polymers were characterized by RBS and UV-vis spectroscopy. The surface morphology of as-implanted and annealed samples was examined by the AFM method and their electrical properties by sheet resistance measurement.

  17. The use of PEEK nanorod arrays for the fabrication of nanoporous surfaces under high temperature: SiNx example.

    PubMed

    Martín, Jaime; Martín-González, Marisol

    2012-09-21

    Large area silicon nitride (SiN(x)) nanoporous surfaces are fabricated using poly(ether-ether-ketone) (PEEK) nanorod arrays as a template. The procedure involves manipulation of nanoporous anodic aluminum oxide (AAO) templates in order to form an ordered array of PEEK nanopillars with high temperature resistant characteristics. In this context, self-ordered AAO templates are infiltrated with PEEK melts via the "precursor film" method. Once the melts have been crystallized in the porous structure of AAO, the basis alumina layer is removed, yielding an ordered array of PEEK nanopillars. The resulting structure is a high temperature and chemical resistant polymeric nanomold, which can be utilized in the synthesis of nanoporous materials under aggressive conditions. Such conditions are high temperatures (up to 320 °C), vacuum, or extreme pH. For example, SiN(x) nanopore arrays have been grown by plasma enhanced chemical vapor deposition at 300 °C, which can be of interest as mold for nanoimprint lithography, due to its hardness and low surface energy. The SiN(x) nanopore array portrays the same characteristics as the original AAO template: 120 nm diameter pores and an interpore distance of 430 nm. Furthermore, the aspect ratio of the SiN(x) nanopores can be tuned by selecting an AAO template with appropriate conditions. The use of PEEK as a nanotemplate extends the applicability of polymeric nanopatterns into a temperature regime up to now not accessible and opens up the simple fabrication of novel nanoporous inorganic surfaces. PMID:22854871

  18. The use of PEEK nanorod arrays for the fabrication of nanoporous surfaces under high temperature: SiNx example.

    PubMed

    Martín, Jaime; Martín-González, Marisol

    2012-09-21

    Large area silicon nitride (SiN(x)) nanoporous surfaces are fabricated using poly(ether-ether-ketone) (PEEK) nanorod arrays as a template. The procedure involves manipulation of nanoporous anodic aluminum oxide (AAO) templates in order to form an ordered array of PEEK nanopillars with high temperature resistant characteristics. In this context, self-ordered AAO templates are infiltrated with PEEK melts via the "precursor film" method. Once the melts have been crystallized in the porous structure of AAO, the basis alumina layer is removed, yielding an ordered array of PEEK nanopillars. The resulting structure is a high temperature and chemical resistant polymeric nanomold, which can be utilized in the synthesis of nanoporous materials under aggressive conditions. Such conditions are high temperatures (up to 320 °C), vacuum, or extreme pH. For example, SiN(x) nanopore arrays have been grown by plasma enhanced chemical vapor deposition at 300 °C, which can be of interest as mold for nanoimprint lithography, due to its hardness and low surface energy. The SiN(x) nanopore array portrays the same characteristics as the original AAO template: 120 nm diameter pores and an interpore distance of 430 nm. Furthermore, the aspect ratio of the SiN(x) nanopores can be tuned by selecting an AAO template with appropriate conditions. The use of PEEK as a nanotemplate extends the applicability of polymeric nanopatterns into a temperature regime up to now not accessible and opens up the simple fabrication of novel nanoporous inorganic surfaces.

  19. 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.

  20. 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.

  1. The characterization of PEEK, PET and PI implanted with Co ions to high fluences

    NASA Astrophysics Data System (ADS)

    Mackova, A.; Malinsky, P.; Miksova, R.; Khaibullin, R. I.; Valeev, V. F.; Svorcik, V.; Slepicka, P.; Slouf, M.

    2013-06-01

    Polyimide (PI), polyetheretherketone (PEEK), and polyethylene terephthalate (PET) foils have been implanted with 40 keV Co+ ions at room temperature to the fluences ranging from 0.2 × 1016 cm-2 to 1.0 × 1017 cm-2. Co depth profiles determined by RBS have been compared to SRIM 2008 calculations. The measured projected ranges RP differ slightly from the SRIM simulation because of the compositional changes in polymers implanted to high fluences; especially the widths of the Co profiles are much larger than those simulated by SRIM. Oxygen and hydrogen depletion has been examined using the RBS and ERDA techniques. The surface morphology of the implanted polymers has been characterized using AFM. The PET polymer exhibits lower oxygen escape than the PI and PEEK, but the surface roughness at PET has been affected most significantly after the implantation. Implanted Co atoms tend to aggregate into nanoparticles, the size and distribution of which has been determined from TEM micrographs and using image analysis. The largest diameter of Co particles has been found in implanted PET.

  2. 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

  3. 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

  4. PEEK valve seats cut steam losses in R. J. Reynolds tobacco plants

    SciTech Connect

    Not Available

    1986-11-01

    R.J. Reynolds Tobacco Company wanted to reduce large energy losses due to leaky block valves in high temperature and high pressure steam lines throughout its vast cigarette and pipe tobacco production facilities in downtown Winston-Salem, NC. Valves with metal-to-metal seating were being used to control steam at pressures to 160 psi and temperatures over 500/sup 0/F because few resilient valve seat materials could long withstand the severe service conditions. Possible product contamination due to seat wear, fatigue and hydrolysis was also unacceptable. However, metal-seated valves began to leak excessively shortly after being placed in service due to corrosion by boiler water treatment chemicals, and erosion by rust and scale in the steam lines. Steam losses from leaky block valves were excessive. To minimize costly energy losses from leaky steam valves, Reynolds Tobacco engineers evaluated samples of a recently introduced thermoplastic, polyetheretherketone (PEEK), as a seat material for steam service valves. PEEK has excellent flexural and tensile properties for resistance to fatigue and abrasion, and is substantially unaffected after thousands of hours in pressurized water at 480/sup 0/F. The polymer is virtually inert to all chemicals, dissolving only in concentrated sulfuric acid. The 94 V-O flammability rating with negligible toxic gas generation during combustion is also a desirable property in tobacco processing applications. Reynolds Tobacco now has a umber of PEEK-seated ball and butterfly valves that have provided tight shut-off for over four years in high pressure and high temperature steam lines. Some of the test valves have leaked, but the problem was not attributed to failure of the seat material.

  5. Clinical outcomes of two types of cages used in transforaminal lumbar interbody fusion for the treatment of degenerative lumbar diseases: n-HA/PA66 cages versus PEEK cages.

    PubMed

    Deng, Qian-xing; Ou, Yun-sheng; Zhu, Yong; Zhao, Zeng-hui; Liu, Bo; Huang, Qiu; Du, Xing; Jiang, Dian-ming

    2016-06-01

    This study reports the clinical effects of nano-hydroxyapatite/polyamide66 cages (n-HA/PA66 cages) and compares the clinical outcomes between n-HA/PA66 and polyetheretherketone cages (PEEK cages) for application in transforaminal lumbar interbody fusion (TLIF). A retrospective and case-control study involving 124 patients using n-HA/PA66 cages and 142 patients using PEEK cages was conducted. All patients underwent TLIF and had an average of 2-years of follow-up. The Oswestry Disability Index and Visual Analog Scale were selected to assess the pain of low back and leg, as well as neurological status. The intervertebral space height and segmental angle were also measured to estimate the radiological changes. At the 1-year and final follow-ups, the fusion and subsidence rates were evaluated. There was no significant difference between the two groups regarding clinical and radiological results. At the final follow-up, the bony fusion rate was 92.45 and 91.57 % for the n-HA/PA66 and PEEK groups, respectively, and the subsidence rate was 7.55 and 8.99 %, respectively. The study indicated that both n-HA/PA66 and PEEK cages could promote effective clinical and radiographic outcomes when used to treat degenerative lumbar diseases. The high fusion and low subsidence rates revealed that n-HA/PA66 cages could be an alternative ideal choice as the same to PEEK cages for lumbar reconstruction after TLIF. PMID:27091044

  6. 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

  7. 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.

  8. 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. PMID:25733834

  9. 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.

  10. 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.

  11. 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

  12. Fatigue fracture behavior of PEEK

    SciTech Connect

    Brillhart, M.; Botsis, J. )

    1993-09-01

    Experimental results on fatigue crack propagation in PEEK under different load levels, specimen thickness, and environmental temperatures (Brillhart, 1991; Brillhart and Botsis, 1992) are analyzed. When the kinetic data are plotted against J1 = sigma sub y delta (where sigma sub y is the yield stress of the material and delta is the crack tip opening displacement), the crack speed is practically independent of the load level, specimen thickness, and environmental temperatures up to 75 C. The experimental data is confronted with a power type kinetic equation and the kinetic equation of the crack layer model. The analysis indicates that both kinetic equations describe well the data under a wide spectrum of loading conditions. 7 refs.

  13. 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.

  14. Characterization of PEEK and short-fiber PEEK thermoplastic composites

    SciTech Connect

    Motz, H.

    1987-01-01

    Various topics in the areas of processing, structure, and properties in PEEK and its short-fiber composites are treated. Crystallization at constant temperatures and under nonisothermal conditions was analyzed using time-temperature-transformation curves. Correlation between isothermal and continuous cooling curves allows the rate of cooling needed to manufacture a product with a specific microstructure to be determined. The crystallization range (time or temperature) can be predicted for various heat treatments. In large-dimensioned polymer parts, crystallization does not develop uniformly. A finite-difference approach predicts the temperature distributions within the part for a variety of conditions, so that processing conditions that cause the inhomogeneities can be avoided. Crystallization temperature is important with respect to spherulitic morphology. The lathlike crystallites of adjacent spherulites formed at medium temperatures interweave, whereas a noncrystalline layer separates spherulites formed at higher temperatures. Carbon fibers are more effective nucleating agents than glass fibers, though not all fibers show transcrystallinity. Generally, the fibers did not seem to accelerate the crystallization process. But, they improve the mechanical properties, strength and modulus, at the expense of toughness.

  15. 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

  16. 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

  17. Comparative study of flexural fatigue properties of epoxy and PEEK composites and matrices

    SciTech Connect

    Trotignon, J.P.; Verdu, J.

    1993-12-31

    Fatigue tests at 5 Hz, ambient temperature, were performed until rupture on carbon fiber unidirectional composites based on two types of matrix: epoxy network (Tg = 483 K) and semicrystalline polyetheretherketone (PEEK). Similar tests were also made on the unreinforced matrices. All the fatigue test made on pure matrices were run in the alternate mode. The fatigue tests on composites has been run in the ondulated mode with a minimum/maximum stress ratio of 0.1. Two loading configurations, respectively 3 and 4 points bending, were compared in conditions where flexural and shear stress-levels were identical for both materials. The results can be summarized as follows: for both composites, there is a wide scatter of lifetimes, typically from 10{sup 3} to 10{sup 5} cycles for stress levels ranging from 1700 to 2000 MPa in the 3 points bending configuration and 1300-1700 MPa in the 4 points configuration. The scatter is presumably due to a random crack initiation by fiber rupture. The systematic difference between 3 and 4 points bending was previously observed in the case of glass fiber composites and interpreted in terms of difference of loaded volume. These interpretations are supported by SEM observations revealing also the existence of a preferential initiation in the interply region. Testing in pure matrix samples reveals a big difference between both polymers since, in the 10{sup 3} 10{sup 5} cycles lifetime interval, the stress varies between 105 and 80 MPa for PEEK and 50 and 30 MPa for epoxy. It appears thus that, in the case under study, the intrinsic fatigue behavior of the matrix plays practically no role on the composite fatigue.

  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. 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

  20. Superhydrophobic PEEK/PTFE composite coating

    NASA Astrophysics Data System (ADS)

    Song, Hao-Jie; Zhang, Zhao-Zhu; Men, Xue-Hu

    2008-04-01

    A simple and inexpensive method for forming a PEEK/PTFE superhydrophobic surfaces by controlling the topographical microstructures by adjusting the curing temperature has been proposed. The resulting porous surface, with ribbon-like randomly distributed double-scale structure and the lowest surface energy hydrophobic groups (-CF3) has a water contact angle of 161°.

  1. Fabrication of an SU-8 based microfluidic reactor on a PEEK substrate sealed by a 'flexible semi-solid transfer'(FST) process

    NASA Astrophysics Data System (ADS)

    Song, Yujun; Kumar, Challa S. S. R.; Hormes, Josef

    2004-07-01

    A continuous flow polymeric microfluidic reactor utilizing SU-8 as a photoresist on a PEEK (polyetheretherketone) substrate was fabricated by standard UV lithography. Embedded multilayer structures were fabricated between the substrate and the inlets and outlet of the microfluidic reactor that facilitated fabrication of the entire microfluidics using SU-8, resulting in improved bonding between the substrate and the pattern. A 'flexible semi-solid transfer' (FST) process, based on a reduced exposure dosage, was developed to seal the microfluidic channels. Scanning electron microscopy (SEM) images and photographs revealed no trace of blockages in channels due to the sealing process. The maximum pressure drop without any leakage was found to be 2.1 MPa. The microfluidic reactor withstood temperatures as high as 150 °C and was found to be suitable for carrying out wet chemical synthesis.

  2. Photopyroelectric response of PTCa/PEEK composite

    NASA Astrophysics Data System (ADS)

    Estevam, Giuliano Pierre; de Melo, Washington Luiz Barros; Sakamoto, Walter Katsumi

    2011-02-01

    A pyroelectric composite made of calcium modified lead titanate ceramic and polyether-ether-ketone high performance polymer was obtained in the film form by hot pressing the ceramic/polymer mixture into the desired composition. After polarization with a suitable electric field, a ceramic composite film (60% vol.) exhibited a pyroelectric figure of merit three times higher than that of a lead zirconate titanate ceramic. The material was used as infrared radiation sensor. The voltage responsivity decreases with the inverse of the frequency showing the same behavior of the thermally thick sensor. The reproducibility of the sensor responses was observed.

  3. Study of the Splat-Substrate Interface for a PEEK Coating Plasma-Sprayed onto Aluminum Substrates

    NASA Astrophysics Data System (ADS)

    Wu, J.; Munroe, P. R.; Withy, B.; Hyland, M. M.

    2010-01-01

    The quality of coatings made using thermal spray processes depends greatly on the degree of adhesion between the substrate and its coating. Yet the bonding mechanisms between a substrate and coating are not well understood. In this study, polyetheretherketone (PEEK) powder was plasma-sprayed to form single splats on aluminum substrates, which had undergone various surface treatments, including boiled (BT), etched (E, ET), and polished (PT), all of which had also been thermally treated to remove water from the substrate surface, with the exception of one etched aluminum substrate. Scanning electron microscopy was used to give an overview of the surface and splat morphology. The splat-substrate interfaces were studied in detail using focused ion beam imaging and transmission electron microscopy, to characterize microstructural features within the splat-substrate interface, including inter/intrasplat pores, pores along the splat-substrate interface, level of contact between the splat and the substrate, etc. The results showed that the splat-substrate interface for the BT and the E substrate surface had poor level of contact, with a high number of small pores (<1 μm) along the splat-substrate interface for the BT splat-substrate interface, and the formation of a near-continuous crevice between the PEEK splat and the aluminum substrate for the E substrate surface. The presence of the fine needle-like network of oxide layer on the BT substrate surface may have restricted the flow of the molten PEEK on the aluminum substrate, and the possible presence of physisorbed and chemisorbed water on the E substrate surface may have reduced the level of contact between the PEEK and the aluminum substrate. In contrast, specimens which had undergone thermal treatment to minimize the presence of water on the substrate surface, such as the ET and PT substrate surface, exhibited high level of contact at the splat-substrate interface. The number of pores for the ET and the PT splat

  4. The effect of stress rate on crack damage evolution in polystyrene and PEEK. Ph.D. Thesis

    SciTech Connect

    Gregory, B.L.

    1993-01-01

    The effects of stress rate on fatigue crack propagation (FCP) in polystyrene (PS) and polyetheretherketone (PEEK) were examined emphasizing damage evolution during fatigue fracture. Extruded and compression molded PS were studied. Craze distributions along trailing edges of successive process zone configurations in each material were self-similar. A core of dense crazing was observed in the extruded PS; no core was observed in the compression molded material. These results have important implications for the kinematics of process zone evolution in compression molded PS. Crack growth kinetics were treated as dl/dn and dl/dt. Consideration of the loading waveform and the load-time-area (LTA) revealed that LTA and rate effects couldn`t be decoupled. However, by treating the data as dl/dt the contribution of LTA constant, and the effect of stress rate was determined. Attempts were made to quantify the contributions of fatigue and creep LTA on total FCP kinetics by linear summation. While these failed, it was subsequently determined that two linear regimes separated by a characteristic period could approximate the data. The contributions of both stress rate and LTA varied above and below this characteristic period. From this analysis, the contributions of time and cycle reversal could be evaluated. Crack growth due to creep exhibited strong correlation with an exponential function compatible with stress-temperature activated processes. The crack damage evolution of PEEK as a function of stress rate during fatigue was also investigated. A brittle-ductile transition was observed characterized by a transformation at the crack tip from a rounded to a triangular (90 deg angle) crack front. The results showed that the damaged material ahead of the crack tip behaved as an elastic perfectly plastic material (plane stress conditions). This damage zone was further characterized as a volume of transformed material.

  5. Effect of Biceps Tenodesis Using PEEK Screw on the Torsional Strength of Humerus

    PubMed Central

    Mellano, Chris; Shin, Jason J.; Mascarenhas, Randhir; Shewman, Elizabeth; Wang, Vincent; Romeo, Anthony A.; Verma, Nikhil N.; Forsythe, Brian

    2015-01-01

    Objectives: Biceps tendoesis is a commonly accepted surgical option for long head biceps related pathology. Sub-pectoral tenodesis with interference screw offers reproducible outcomes with high biomechanical strength allowing for accelerated rehabilitiation. However, there is concern regarding potential fracture risk associate with a diaphyseal humeral tunnel particularly in an athletic population. The purpose of this study was to determine the amount of torsional strength reduction in the humerus resulting from an unicortically drilled hole, and to evaluate the effect of inserting a tenodesis screw into the drilled defect. We hypothesized that unicortical drilling would weaken the humerus and that the use of tenodesis screws would restore strength to the humerus. Methods: Twenty (10 matched pairs) of fresh frozen full length humeri (mean age 55.3 years, range 37-70 years) were used to perform this study. All humeral specimens were stripped of all soft tissue, except for the pectoralis major tendon, which was used to determine location of the tenodesis. Specimens were allocated to either Screw (n=5) or Empty Ream Group (n=5) and the matching contralateral pairs remained intact. In the Empty Ream specimens, an 8 mm unicortical hole was placed into the bicipital groove 1 cm proximal to the inferior border of the pectoralis major tendon. The humeri in the Screw Group were prepared in the same manner and filled with a 8mm x 12 mm polyetheretherketone (PEEK) screw. All specimens were tested until failure under torsional loading at a rate of 1 degree/second. Peak torque, angular deformation at peak, and total energy to failure were recorded. A paired t-test was used to compare data from left and right humeri for each of the two groups. Data were also evaluated as the ratio of the intervention humerus to its contralateral intact humerus in order to compare Tenodesis Screw and Empty Ream groups via a 2-tailed, unpaired t-test. Statistical significance was assumed for P <0

  6. 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

  7. Influence of contact pressure, cross-shear and counterface material on the wear of PEEK and CFR-PEEK for orthopaedic applications.

    PubMed

    Brockett, C L; Carbone, S; Abdelgaied, A; Fisher, J; Jennings, L M

    2016-10-01

    Total joint replacement is a successful surgical intervention for the treatment of the degeneration of many joints, particularly the hip and knee. As the demand for joint replacement grows, and the life expectancy of the population increases, the performance requirements of these implants also changes. New materials, to improve longevity and enhance performance have been explored including PEEK and CFR-PEEK. This study investigated whether CFR-PEEK and PEEK were appropriate materials for total joint replacement by examining wear performance in simple configuration studies articulating against cobalt chrome under a range of cross-shear and contact pressure conditions. Simple geometry pin on plate studies were conducted for one million cycles for each test condition, with the contact pressure and cross-shear conditions representing a range in which the material may need to operate in-vivo. The wear factor for PEEK was significantly higher than CFR-PEEK and conventional polyethylene under all test conditions. Both PEEK and CFR-PEEK wear were influenced by contact pressure, with the highest wear factors for both materials measured at the highest pressure conditions. PEEK appeared to have a cross-shear dependent wear response, but this was not observed for the CFR-PEEK material. This study has further characterised the wear performance of two materials that are gaining interest for total joint replacement. The wear performance of the PEEK material showed poorer wear performance compared to polyethylene when articulating with a metal counterface, but the performance of the CFR-PEEK material suggested it may provide a suitable alternative to polyethylene in some applications. The wear performance of CFR-PEEK was poorer than polyethylene when it was used as the plate, when there was translation of the contact zone over the surface of the CFR-PEEK plate. This has implications for applications in low conforming contacts, such as lower conformity knee replacement.

  8. Influence of contact pressure, cross-shear and counterface material on the wear of PEEK and CFR-PEEK for orthopaedic applications.

    PubMed

    Brockett, C L; Carbone, S; Abdelgaied, A; Fisher, J; Jennings, L M

    2016-10-01

    Total joint replacement is a successful surgical intervention for the treatment of the degeneration of many joints, particularly the hip and knee. As the demand for joint replacement grows, and the life expectancy of the population increases, the performance requirements of these implants also changes. New materials, to improve longevity and enhance performance have been explored including PEEK and CFR-PEEK. This study investigated whether CFR-PEEK and PEEK were appropriate materials for total joint replacement by examining wear performance in simple configuration studies articulating against cobalt chrome under a range of cross-shear and contact pressure conditions. Simple geometry pin on plate studies were conducted for one million cycles for each test condition, with the contact pressure and cross-shear conditions representing a range in which the material may need to operate in-vivo. The wear factor for PEEK was significantly higher than CFR-PEEK and conventional polyethylene under all test conditions. Both PEEK and CFR-PEEK wear were influenced by contact pressure, with the highest wear factors for both materials measured at the highest pressure conditions. PEEK appeared to have a cross-shear dependent wear response, but this was not observed for the CFR-PEEK material. This study has further characterised the wear performance of two materials that are gaining interest for total joint replacement. The wear performance of the PEEK material showed poorer wear performance compared to polyethylene when articulating with a metal counterface, but the performance of the CFR-PEEK material suggested it may provide a suitable alternative to polyethylene in some applications. The wear performance of CFR-PEEK was poorer than polyethylene when it was used as the plate, when there was translation of the contact zone over the surface of the CFR-PEEK plate. This has implications for applications in low conforming contacts, such as lower conformity knee replacement. PMID

  9. Cervical Laminoplasty

    MedlinePlus

    ... Treatments for Spinal Pain Surgical Options Anterior Cervical Fusion Artificial Disc Replacement Bone Graft Alternatives Bone Morphogenetic ... Discectomy Percutaneous Vertebral Augmentation Posterior Cervical Foraminotomy Spinal Fusion ... Medicine Cervical Laminoplasty What is ...

  10. 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

  11. PEEK biomaterials in trauma, orthopedic, and spinal implants.

    PubMed

    Kurtz, Steven M; Devine, John N

    2007-11-01

    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

  12. Remelting of Flame Spraying PEEK Coating Using Lasers

    NASA Astrophysics Data System (ADS)

    Soveja, A.; Costil, S.; Liao, H.; Sallamand, P.; Coddet, C.

    2010-01-01

    Flame spraying is frequently used for polyether ether ketone (PEEK) and PTFE coating deposition on metallic surfaces. However, this process has a certain number of limitations, particularly on the coating quality such as high porosity, low interfacial adherence, etc. For that reason a thermal post-processing step is often necessary. The objective of this study is to analyze the effects produced during a laser beam heat treatment on morphological structure (compactness) of PEEK coatings and their mechanical properties (adherence and tribology). The influence of the laser beam wavelength (by using a Nd:YAG, CO2 or diode lasers) on compactness of the flame sprayed PEEK coating deposited on metallic substrate (304L) was analyzed. Since the value of laser light absorption coefficient of the PEEK coating depends on the laser wavelength, an optimization of the operational parameters for each laser has been carried out in order to achieve melting but not burning of the PEEK coating. Nevertheless, whatever the laser wavelengths used, the results showed a good effect of the laser treatment: improvement of both polymer coating compactness and its adherence to the substrate.

  13. X-Ray-Scattering Measurements Of Strain In PEEK

    NASA Technical Reports Server (NTRS)

    Cebe, Peggy; Lowry, Lynn E.; Chung, Shirley Y.; Yavrouian, Andre H.; Gupta, Amitava

    1988-01-01

    Internal stress relieved by heating above glass-transition temperature. Report describes wide-angle x-ray scattering and differential scanning calorimetry of specimens of poly(etheretherketone) having undergone various thermal treatments. Wide-angle x-ray scattering particularly useful in determining distances between atoms, crystallinity, and related microstructurally generated phenomena, as thermal expansion and strain. Calorimetric measurements aid interpretation of scattering measurements by enabling correlation with thermal effects.

  14. Characterisation of PEEK, PET and PI implanted with 80 keV Fe+ ions to high fluencies

    NASA Astrophysics Data System (ADS)

    Mackova, A.; Malinsky, P.; Miksova, R.; Hnatowicz, V.; Khaibullin, R. I.; Slepicka, P.; Svorcik, V.

    2014-07-01

    Polyimide (PI), polyetheretherketone (PEEK) and polyethylene terephthalate (PET) foils were implanted with 80 keV Fe+ ions at room temperature at fluencies of 0.2 × 1016 cm-2- 5.0 × 1016 cm-2. The implanted polymers were subsequently annealed at 200 °C for 20 min. The depth profiles of implanted Fe atoms and compositional changes of the implanted polymers were characterised by RBS and ERDA methods. A significant shift of the Fe concentration maximum to the sample surface with increasing ion fluence was observed and annealing does not influence the Fe profiles. The implanted Fe profiles cannot be reproduced by SRIM and TRIDYN simulations. Hydrogen desorption from the surface layer of all polymers is observed, the effect being the most pronounced on PET. Desorption of oxygen from the samples implanted to lower fluences is observed too. On the samples implanted to the highest fluence of 5.0 × 1016 cm-2, however, oxygen concentration increases to the value close to that of pristine polymer, this phenomenon is strongly pronounced after the annealing, which is provided in the ambient atmosphere. The electrical, optical and structural properties of the implanted polymers were investigated by sheet resistance measurement and UV-Vis spectroscopy. With increasing ion fluence, the sheet resistance decreases, but a saturation effect is achieved at a fluence of 5.0 × 1016 cm-2. UV-Vis absorbance increases simultaneously with the decline of the optical band gap Eg. After annealing, no significant changes in UV-Vis spectra or in electrical properties were observed.

  15. Fatigue delamination behavior of PEEK thermoplastic composite laminates

    NASA Technical Reports Server (NTRS)

    O'Brien, T. K.

    1986-01-01

    The delamination resistance of graphite-reinforced PEEK composites was quantified by conducting static and cyclic edge delamination tests on (35n/-35n/0n/90n)s AS4/PEEK laminates, where n = 1, 2. The experimentally determined mechanical delamination onset strains were used to calculate the critical strain-energy release rate for delamination onset as a function of fatigue cycle. The delamination onset strains decreased dramatically with fatigue cycles and then began to level off to an endurance limit at 1 million cycles. Although the static interlaminar fracture toughness of the AS4/PEEK composite is much greater than the toughness of graphite epoxy composites, the delamination fatigue threshold, calculated from the cyclic strain endurance limit at 1 million cycles, was only slightly greater than the threshold for graphite epoxy composites. The contribution of residual thermal stresses to delamination in the AS4/PEEK is substantial due to the large temperature range between the manufacture and the room temperatures.

  16. Latino Hillbilly: An Interview with Marcos McPeek Villatoro.

    ERIC Educational Resources Information Center

    Minick, Jim; McPeek Villatoro, Marcos

    2001-01-01

    Novelist and faculty member McPeek Villatoro, son of a Salvadoran mother and an Appalachian father, discusses his childhood in Tennessee and San Francisco, racism encountered for being Latino or Appalachian, embracing his Latino roots, similarities between Appalachian and rural Central American cultures, the importance of teachers raising…

  17. 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.

  18. 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.

  19. Cervical Cancer

    MedlinePlus

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

  20. Red selenium nanoparticles and gray selenium nanorods as antibacterial coatings for PEEK medical devices.

    PubMed

    Wang, Qi; Mejía Jaramillo, Alejandra; Pavon, Juan J; Webster, Thomas J

    2016-10-01

    Bacterial infections are commonly found on various poly(ether ether ketone) (PEEK) medical devices (such as orthopedic instruments, spinal fusion devices, and segments in dialysis equipment), and thus, there is a significant need for introducing antibacterial properties to such materials. The objective of this in vitro study was to introduce antibacterial properties to PEEK medical devices by coating them with nanosized selenium. In this study, red selenium (an elemental form of selenium) nanoparticles were coated on PEEK medical devices through a quick precipitation method. Furthermore, with heat treatment at 100°C for 6 days, red selenium nanoparticles were transferred into gray selenium nanorods on the PEEK surfaces. Bacteria test results showed that both red and gray selenium-coated PEEK medical devices significantly inhibited the growth of Pseudomonas aeruginosa compared with uncoated PEEK after either 1, 2, or 3 days. Red selenium nanoparticle-coated PEEK showed less bacteria growth on its surface than gray selenium nanorod-coated PEEK after 3 days. This study demonstrated that red, and to a lesser extent gray, nanosized selenium could be used as potential antibacterial coatings to prevent bacteria function on PEEK medical devices. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1352-1358, 2016. PMID:26138597

  1. Elaboration of submicron structures on PEEK polymer by femtosecond laser

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    In this work, laser parameters initiating the emergence of periodic structures, so-called ripples on poly (ether ether ketone) (PEEK) surfaces, are investigated. PEEK was used in its semi-crystalline and amorphous forms. Polymer surfaces were treated locally by performing a matrix of laser impacts to highlight the influence of the crystallinity in ultrashort laser interaction. Different surface morphologies or ripples were analyzed by atomic force microscopy and optical interferometry. A map of the presence of these different morphologies according to the laser fluence and the number of pulses was established. Analysis by optical interferometry was carried out and led to the calculations of ablation efficiency. Some significant differences were demonstrated between amorphous and semi-crystalline surfaces. This work revealed topographical information on the local behavior of the irradiated material. Finally, the crystallinity rate of polymer surface seems to be a determinant factor for the periodic nanostructured appearance.

  2. Cervical radiculopathy.

    PubMed

    Iyer, Sravisht; Kim, Han Jo

    2016-09-01

    Cervical radiculopathy is a common clinical scenario. Patients with radiculopathy typically present with neck pain, arm pain, or both. We review the epidemiology of cervical radiculopathy and discuss the diagnosis of this condition. This includes an overview of the pertinent findings on the patient history and physical examination. We also discuss relevant clinical syndromes that must be considered in the differential diagnosis including peripheral nerve entrapment syndromes and shoulder pathology. The natural history of cervical radiculopathy is reviewed and options for management are discussed. These options include conservative management, non-operative modalities such as physical therapy, steroid injections, and operative intervention. While the exact indications for surgical intervention have not yet been elucidated, we provide an overview of the available literature regarding indications and discuss the timing of intervention. The surgical outcomes of anterior cervical decompression and fusion (ACDF), cervical disc arthroplasty (CDA), and posterior cervical foraminotomy (PCF) are discussed. PMID:27250042

  3. 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

  4. Cervical cerclage.

    PubMed

    Suhag, Anju; Berghella, Vincenzo

    2014-09-01

    Cervical cerclage is an obstetric procedure performed for prevention of prematurity. Cerclage was first introduced by Drs Shirodkar and McDonald in the mid-1950s for women with repeated second trimester losses and cervical changes in current pregnancy. Currently, cerclage placement is based on 3 common indications in singleton gestations, including history-indicated (prior multiple early preterm births or second trimester losses), ultrasound-indicated (cervical length <25 mm before 24-wk gestational age in women with prior spontaneous preterm birth) and physical examination-indicated (cervical dilation on manual or physical examination before 24 wk).

  5. 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

  6. 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. PMID:27058498

  7. 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.

  8. Cervical Cancer

    MedlinePlus

    ... dysplasia of the cervix, vagina, or vulva • A family history of cervical cancer •Smoking •Certain sexually transmitted infections , such as chlamydia • ... to treat your cancer, you still need cervical cancer screening. Cells are taken from the upper vagina ... smallest units of a structure in the body; the building blocks for all ...

  9. 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.

  10. 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. PMID:26758897

  11. Properties of intermingled carbon/PEEK 3-D woven composites

    NASA Technical Reports Server (NTRS)

    Mohamed, M. H.; Machfud, N. F. N.; Hamouda, H.

    1992-01-01

    The presence of voids is one of the major problems associated with resin infiltration techniques when using 3-D woven preforms. Efforts to reduce the voids invariably result in the creation of microcracks. In this paper, the use of PEEK fibers intermingled with carbon fibers into a multi-layer preform is discussed. Influence of processing parameters, such as temperature, pressure, and consolidation time, on the composite properties is presented. One of the issues emphasized is the effect of pressure on buckling of the Z-reinforcement fibers and the bending behavior.

  12. Effects of microstructural inclusions on fatigue life of polyether ether ketone (PEEK).

    PubMed

    Simsiriwong, Jutima; Shrestha, Rakish; Shamsaei, Nima; Lugo, Marcos; Moser, Robert D

    2015-11-01

    In this study, the effects of microstructural inclusions on fatigue life of polyether ether ketone (PEEK) was investigated. Due to the versatility of its material properties, the semi-crystralline PEEK polymer has been increasingly adopted in a wide range of applications particularly as a biomaterial for orthopedic, trauma, and spinal implants. To obtain the cyclic behavior of PEEK, uniaxial fully-reversed strain-controlled fatigue tests were conducted at ambient temperature and at 0.02 mm/mm to 0.04 mm/mm strain amplitudes. The microstructure of PEEK was obtained using the optical and the scanning electron microscope (SEM) to determine the microstructural inclusion properties in PEEK specimen such as inclusion size, type, and nearest neighbor distance. SEM analysis was also conducted on the fracture surface of fatigue specimens to observe microstructural inclusions that served as the crack incubation sites. Based on the experimental strain-life results and the observed microstructure of fatigue specimens, a microstructure-sensitive fatigue model was used to predict the fatigue life of PEEK that includes both crack incubation and small crack growth regimes. Results show that the employed model is applicable to capture microstructural effects on fatigue behavior of PEEK.

  13. Effects of microstructural inclusions on fatigue life of polyether ether ketone (PEEK).

    PubMed

    Simsiriwong, Jutima; Shrestha, Rakish; Shamsaei, Nima; Lugo, Marcos; Moser, Robert D

    2015-11-01

    In this study, the effects of microstructural inclusions on fatigue life of polyether ether ketone (PEEK) was investigated. Due to the versatility of its material properties, the semi-crystralline PEEK polymer has been increasingly adopted in a wide range of applications particularly as a biomaterial for orthopedic, trauma, and spinal implants. To obtain the cyclic behavior of PEEK, uniaxial fully-reversed strain-controlled fatigue tests were conducted at ambient temperature and at 0.02 mm/mm to 0.04 mm/mm strain amplitudes. The microstructure of PEEK was obtained using the optical and the scanning electron microscope (SEM) to determine the microstructural inclusion properties in PEEK specimen such as inclusion size, type, and nearest neighbor distance. SEM analysis was also conducted on the fracture surface of fatigue specimens to observe microstructural inclusions that served as the crack incubation sites. Based on the experimental strain-life results and the observed microstructure of fatigue specimens, a microstructure-sensitive fatigue model was used to predict the fatigue life of PEEK that includes both crack incubation and small crack growth regimes. Results show that the employed model is applicable to capture microstructural effects on fatigue behavior of PEEK. PMID:26301567

  14. [Cervical cerclage].

    PubMed

    Akladios, C Y; Sananes, N; Gaudineau, A; Boudier, E; Langer, B

    2015-10-01

    Cervical cerclage aims to strengthen not only the mechanical properties of the cervix, but also its immunological and anti-infectious functions. The demonstration of a strong interrelation between cervical insufficiency as well as decreased cervical length at endo-vaginal ultrasonography and infection has changed the indications cerclage. Actually we can distinguish three indications for cerclage: prophylactic, for obstetrical history; therapeutic, for shortened cervical length at ultrasonography in patients at risk and; emergency cerclage in case of threatening cervix at physical examination. The McDonald's technique is the most recommended. In case of failure, it is proposed to realize cerclage at a higher level on the cervix either by vaginal or abdominal route. PMID:26144289

  15. 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 ...

  16. Cervical spondylosis

    MedlinePlus

    Cervical osteoarthritis; Arthritis - neck; Neck arthritis; Chronic neck pain; Degenerative disk disease ... pain using stretches. The therapist will teach you exercises that make your neck muscles stronger. The therapist ...

  17. Cervical polyps

    MedlinePlus

    Vaginal bleeding - polyps ... The exact cause of cervical polyps is not known. They may occur with: An abnormal response to increased levels of the female hormone estrogen Chronic inflammation Clogged ...

  18. 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.

  19. Rheology and mechanics of polyether(ether)ketone - Polyetherimide blends for composites in aeronautics

    NASA Astrophysics Data System (ADS)

    Rosa, Mattia; Grassia, Luigi; D'Amore, Alberto; Carotenuto, Claudia; Minale, Mario

    2016-05-01

    In the present work rheological and mechanical properties of PEEK-PEI blends were investigated. Besides the pure components, blends with PEI concentration ranging from 10% to 90% in mass were considered. Oscillatory experiments in controlled atmosphere were conducted at different frequencies and temperatures. The frequency responses at different temperatures allowed using the TTS principle to reconstruct the master curves. All systems showed a shear thinning behavior and a flux index increasing with the percentage of PEI. The zero-shear viscosity was computed with the implementation of the Cross model and showed a decreasing behavior with the percentage of PEI. The relaxation time estimated from the crossover value of storage and loss moduli didn't change significantly with blend composition, suggesting the non-sensibility of the elasticity of the system. Lastly, tensile tests were executed to investigate the dependence of Young modulus in the different blends.

  20. Conference peeks into the past and future of ocean science

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    During the past 50 fifty years, oceanographic research in the United States has birthed many landmark discoveries and programs that have changed our perception of the seas, how they work, and how mankind interacts with them. During these decades, ocean science also drifted through the Cold War as a frequent and strategic partner with the military, and then largely was weaned away from that source of funding as the National Science Foundation (NSF) became perhaps the principle supporter for the science.Speakers at a NSF conference held in Washington, D.C. in October reviewed some of these achievements, as well as anecdotal remembrances of programs, priorities, and personalities that have shaped ocean sciences over the past five decades, since NSF was founded in 1950. Speakers also peeked into the future of oceanography and significant affects it has on climate, coastal processes, human health, and other societal concerns.

  1. 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…

  2. General Information about Cervical Cancer

    MedlinePlus

    ... Research Cervical Cancer Treatment (PDQ®)–Patient Version General Information About Cervical Cancer Go to Health Professional Version ... the NCI website . Cervical Cancer During Pregnancy General Information About Cervical Cancer During Pregnancy Treatment of cervical ...

  3. Influence of cooling rate on interlaminar fracture properties of unidirectional commingled CF/PEEK composites

    NASA Astrophysics Data System (ADS)

    Beehag, Andrew; Ye, Lin

    1995-05-01

    The influence of cooling rates on the mechanical property profile (transverse flexure properties and modes-I and -II interlaminar fracture toughness) has been investigated for unidirectional commingled CF/PEEK composites. A laboratory hot press with a steel mould was used to process the composites at 400°C for 60 min, at an applied pressure of 1 MPa. Cooling rates from fast (quenching in oil) to slow (hot press cooling) were achieved at ambient pressure. The results indicate that different matrix morphology was found at different cooling conditions, although deconsolidation occurred in the CF/PEEK composites during cooling. When the cooling rate was shifted from slow to fast, consolidation quality of the CF/PEEK composites was improved. The resulting effect of the consolidation quality and cooling rates on the mechanical property profile of commingled CF/PEEK composites is presented. It was found that the effect of the cooling rate on the mechanical property profile of the commingled CF/PEEK composites could not be isolated from the consolidation quality.

  4. DRAW+SneakPeek: Analysis workflow and quality metric management for DNA-seq experiments

    PubMed Central

    Lin, Chiao-Feng; Valladares, Otto; Childress, D. Micah; Klevak, Egor; Geller, Evan T.; Hwang, Yih-Chii; Tsai, Ellen A.; Schellenberg, Gerard D.; Wang, Li-San

    2013-01-01

    Summary: We report our new DRAW+SneakPeek software for DNA-seq analysis. DNA resequencing analysis workflow (DRAW) automates the workflow of processing raw sequence reads including quality control, read alignment and variant calling on high-performance computing facilities such as Amazon elastic compute cloud. SneakPeek provides an effective interface for reviewing dozens of quality metrics reported by DRAW, so users can assess the quality of data and diagnose problems in their sequencing procedures. Both DRAW and SneakPeek are freely available under the MIT license, and are available as Amazon machine images to be used directly on Amazon cloud with minimal installation. Availability: DRAW+SneakPeek is released under the MIT license and is available for academic and nonprofit use for free. The information about source code, Amazon machine images and instructions on how to install and run DRAW+SneakPeek locally and on Amazon elastic compute cloud is available at the National Institute on Aging Genetics of Alzheimer’s Disease Data Storage Site (http://www.niagads.org/) and Wang lab Web site (http://wanglab.pcbi.upenn.edu/). Contact: gerardsc@mail.med.upenn.edu or lswang@mail.med.upenn.edu PMID:23943636

  5. Antibacterial Property of Cold-Sprayed HA-Ag/PEEK Coating

    NASA Astrophysics Data System (ADS)

    Sanpo, Noppakun; Tan, Meng Lu; Cheang, Philip; Khor, K. A.

    2009-03-01

    The antibacterial behavior of HA-Ag (silver-doped hydroxyapatite) nanopowder and their composite coatings were investigated against Escherichia coli (DH5α). HA-Ag nanopowder and PEEK (poly-ether-ether-ketone)-based HA-Ag composite powders were synthesized using in-house powder processing techniques. Bacteria culture assay of HA-Ag nanopowder and their composite powders displayed excellent bacteriostatic activity against E. coli. The antibacterial activity increased with increasing concentration of HA-Ag nanoparticle in these composite powders. These nanocomposite powders were subsequently used as feedstock to generate antibacterial coatings via cold spray technology. The ratios of HA-Ag to PEEK in their composite powders were 80:20, 60:40, 40:60, and 20:80 (wt.%). Microstructural characterization and phase analysis of feedstock powders and as-deposited coatings were carried out using FESEM/EDX and XRD. Antibacterial nanocomposite HA-Ag/PEEK coatings were successfully deposited using cold spraying parameters of 11-12 bars at preheated air temperature between 150 and 160 °C. These as-sprayed coatings of HA-Ag/PEEK composite powders comprising varying HA-Ag and PEEK ratios retained their inherent antibacterial property as verified from bacterial assay. The results indicated that the antibacterial activity increased with increasing HA-Ag nanopowder concentration in the composite powder feedstock and cold-sprayed coating.

  6. 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.

  7. 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.

  8. [Cervical radiculopathy].

    PubMed

    Kuijper, B

    2014-10-01

    Cervical radiculopathy is a common cause of pain in the arm. It is caused by nerve root compression in the neck, as a consequence of a herniated disc, or spondyliotic foraminal stenosis. It causes severe pain, especially during the first few weeks, and paraesthesias in the forearm and hand. Patients also suffer from neck pain and loss of strength in the relevant arm. The arm pain can be exacerbated by certain movements of the head; these should be avoided as much as possible. Diagnosis can be made on the basis of history and physical examination. The pain generally disappears without active patient treatment. A semi-rigid cervical collar is recommended to accelerate pain relief. In cases of persistent pain, surgery will be considered. In such cases an MRI should be performed to show the cause and level of nerve root compression. PMID:26185991

  9. [Cervical radiculopathy].

    PubMed

    Kuijper, B

    2014-10-01

    Cervical radiculopathy is a common cause of pain in the arm. It is caused by nerve root compression in the neck, as a consequence of a herniated disc, or spondyliotic foraminal stenosis. It causes severe pain, especially during the first few weeks, and paraesthesias in the forearm and hand. Patients also suffer from neck pain and loss of strength in the relevant arm. The arm pain can be exacerbated by certain movements of the head; these should be avoided as much as possible. Diagnosis can be made on the basis of history and physical examination. The pain generally disappears without active patient treatment. A semi-rigid cervical collar is recommended to accelerate pain relief. In cases of persistent pain, surgery will be considered. In such cases an MRI should be performed to show the cause and level of nerve root compression.

  10. Optimization of the ultrasonic welding of PEEK-carbon composites

    SciTech Connect

    Harras, B.; Cole, K.C.; Vu-Khanh, T.

    1995-10-01

    The ultrasonic welding of PEEK-carbon composites was studied in order to better understand the process and determine the optimum welding conditions. The parameters that varied were the applied pressure and the welding time. The optimum applied pressure at the horn-sample interface was found to be 3.8 MPa. The joint properties were evaluated through fracture tests in both Mode I (opening) and Mode II (shear). It was found that the optimum welding time depends very much on the physical configuration of the specimen being welded; this affects the efficiency of conversion of the ultrasound into thermal energy in the composite. However, for both types of specimen tested (Mode I and Mode II) the optimum joint strength was found to correspond to a specific value of total energy input, namely 6.8 J/mm{sup 2}. This gave critical strain energy release rates of G{sub Ic} = 3.2 kJ/m{sup 2} and G{sub IIc} = 4.6 kJ/m{sup 2}. A variation of the energy by 10% in either direction resulted in a decrease in properties by about half. Hence the weld energy can be used as a reliable control parameter to produce joints with strengths equivalent to those of molded composite.

  11. 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. PMID:22353492

  12. 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.

  13. 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.

  14. 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.

  15. Nonlinear analysis of AS4/PEEK thermoplastic composite laminate using a one parameter plasticity model

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    A one-parameter plasticity model was shown to adequately describe the orthotropic 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 nonlinear stress-strain relations were measured and compared with those predicted by the finite element analysis using the one-parameter elastic-plastic constitutive model. The results show that the one-parameter orthotropic plasticity model is suitable for the analysis of elastic-plastic deformation of AS4/PEEK composite laminates.

  16. 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

  17. Characterization of elastic-plastic behavior of AS4/PEEK thermoplastic composite for temperature variation

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    Inelastic and strength properties of AS4/PEEK composites were characterized with respect to temperature variation by using a one-parameter orthotropic plasticity model and a one-parameter failure criterion. Simple uniaxial off-axis tension tests were performed on coupon specimens of unidirectional AS4/PEEK thermoplastic composite at various temperatures. To avoid the complication caused by the extension-shear coupling effect in off-axis testing, new tabs were designed and used on the test specimens. Experimental results showed that the nonlinear behavior of constitutive relations and the strength can be characterized quite well using the one-parameter plasticity model and the failure criterion, respectively.

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

    NASA Astrophysics Data System (ADS)

    Mohiuddin, Mohammad; van Hoa, Suong

    2011-06-01

    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.

  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. Biomarkers in Cervical Cancer

    PubMed Central

    Yim, Eun-Kyoung; Park, Jong-Sup

    2006-01-01

    Cervical cancer, a potentially preventable disease, remains the second most common malignancy in women worldwide. Human papillomavirus (HPV) is the single most important etiological agent in cervical cancer, contributing to neoplastic progression through the action of viral oncoproteins, mainly E6 and E7. Cervical screening programs using Pap smear testing have dramatically improved cervical cancer incidence and reduced deaths, but cervical cancer still remains a global health burden. The biomarker discovery for accurate detection and diagnosis of cervical carcinoma and its malignant precursors (collectively referred to as high-grade cervical disease) represents one of the current challenges in clinical medicine and cytopathology. PMID:19690652

  1. Investigating the compatibility of PEEK polymer for the fabrication of sample cells for use in muon spin spectroscopy

    NASA Astrophysics Data System (ADS)

    Chandrasena, L.; McKenzie, I.; Brodovitch, J.-C.; Mozafari, M.; Cottrell, S. P.; Percival, P. W.

    2014-12-01

    Polyether ether ketone (PEEK) is a thermoplastic polymer with a wide range of applications due to its chemical inertness and thermal stability, and for these reasons sample cells for gas and liquid phase μSR have been constructed from PEEK. Muon levelcrossing resonance (μLCR) studies of PEEK revealed a broad, strong μLCR signal that, we hypothesize, is due to multiple overlapping resonances from the various muonium (Mu) adducts of PEEK. To investigate this, two monomer units from PEEK (4,4'-dihydroxybenzophenone and para-dimethoxybenzene) were studied in solution using transverse-field muon spin rotation (TF-μSR) and μLCR. Two different muoniated radicals were formed by Mu addition to 4,4/- dihydroxybenzophenone and one radical was formed in para-dimethoxybenzene. The μSR spectra were assigned by comparing the experimentally measured muon and proton hyperfine coupling constants with values calculated for the possible structures using Gaussian-09 software with the B3LYP functional and 6-31G basis set. Good agreement was found for cyclohexadienyl- type radicals formed by Mu addition to the benzene rings of the monomer units. We can also infer that these radicals are being formed in PEEK, and based on this we conclude that sample cells made of PEEK are unsuitable for many types of μSR experiment.

  2. 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.

  3. Parent Early Evaluation of Kids: PEEK Outreach Training Project. Final Report.

    ERIC Educational Resources Information Center

    Squires, Jane; Twombly, Liz; Yockelson, Sue

    This report describes achievements and activities of the Parent Early Evaluation of Kids (PEEK) Outreach Project at the University of Oregon. This project focused on assisting state agencies, regional and tribal entities, and local health and education programs to develop comprehensive, low-cost systems for child-find and referral. Rural and inner…

  4. In Vitro Comparison of Dynesys, PEEK, and Titanium Constructs in the Lumbar Spine

    PubMed Central

    Yeager, Matthew S.; Cook, Daniel J.; Cheng, Boyle C.

    2015-01-01

    Introduction. Pedicle based posterior dynamic stabilization systems aim to stabilize the pathologic spine while also allowing sufficient motion to mitigate adjacent level effects. Two flexible constructs that have been proposed to act in such a manner, the Dynesys Dynamic Stabilization System and PEEK rod, have yet to be directly compared in vitro to a rigid Titanium rod. Methods. Human lumbar specimens were tested in flexion extension, lateral bending, and axial torsion to evaluate the following conditions at L4-L5: Intact, Dynesys, PEEK rod, Titanium rod, and Destabilized. Intervertebral range of motion, interpedicular travel, and interpedicular displacement metrics were evaluated from 3rd-cycle data using an optoelectric tracking system. Results. Statistically significant decreases in ROM compared to Intact and Destabilized conditions were detected for the instrumented conditions during flexion extension and lateral bending. AT ROM was significantly less than Destabilized but not the Intact condition. Similar trends were found for interpedicular displacement in all modes of loading; however, interpedicular travel trends were less consistent. More importantly, no metrics under any mode of loading revealed significant differences between Dynesys, PEEK, and Titanium. Conclusion. The results of this study support previous findings that Dynesys and PEEK constructs behave similarly to a Titanium rod in vitro. PMID:26366303

  5. In Vitro Comparison of Dynesys, PEEK, and Titanium Constructs in the Lumbar Spine.

    PubMed

    Yeager, Matthew S; Cook, Daniel J; Cheng, Boyle C

    2015-01-01

    Introduction. Pedicle based posterior dynamic stabilization systems aim to stabilize the pathologic spine while also allowing sufficient motion to mitigate adjacent level effects. Two flexible constructs that have been proposed to act in such a manner, the Dynesys Dynamic Stabilization System and PEEK rod, have yet to be directly compared in vitro to a rigid Titanium rod. Methods. Human lumbar specimens were tested in flexion extension, lateral bending, and axial torsion to evaluate the following conditions at L4-L5: Intact, Dynesys, PEEK rod, Titanium rod, and Destabilized. Intervertebral range of motion, interpedicular travel, and interpedicular displacement metrics were evaluated from 3rd-cycle data using an optoelectric tracking system. Results. Statistically significant decreases in ROM compared to Intact and Destabilized conditions were detected for the instrumented conditions during flexion extension and lateral bending. AT ROM was significantly less than Destabilized but not the Intact condition. Similar trends were found for interpedicular displacement in all modes of loading; however, interpedicular travel trends were less consistent. More importantly, no metrics under any mode of loading revealed significant differences between Dynesys, PEEK, and Titanium. Conclusion. The results of this study support previous findings that Dynesys and PEEK constructs behave similarly to a Titanium rod in vitro. PMID:26366303

  6. 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…

  7. Nano-TiO2/PEEK bioactive composite as a bone substitute material: in vitro and in vivo studies

    PubMed Central

    Wu, Xiaomian; Liu, Xiaochen; Wei, Jie; Ma, Jian; Deng, Feng; Wei, Shicheng

    2012-01-01

    Background Compared with titanium (Ti) and other metal implant materials, poly(ether-ether ketone) (PEEK) shows outstanding biomechanical properties. A number of studies have also reported attractive bioactivity for nano-TiO2 (n-TiO2). Methods In this study, n-TiO2/PEEK nanocomposites were prepared, taking advantage of the unique properties of both PEEK polymer and n-TiO2. The in vitro and in vivo bioactivity of these nanocomposites was assessed against a PEEK polymer control. The effect of surface morphology or roughness on the bioactivity of the n-TiO2/PEEK nanocomposites was also studied. n-TiO2/PEEK was successfully fabricated and cut into disks for physical and chemical characterization and in vitro studies, and prepared as cylindrical implants for in vivo studies. Their presence on the surface and dispersion in the composites was observed and analyzed by scanning and transmission electron microscopy and X-ray photoelectron spectroscopy. Results Bioactivity evaluation of the nanocomposites revealed that pseudopods of osteoblasts preferred to anchor at areas where n-TiO2 was present on the surface. In a cell attachment test, smooth PEEK showed the lowest optical density value (0.56 ± 0.07) while rough n-TiO2/PEEK exhibited the highest optical density value (1.21 ± 0.34, P < 0.05). In in vivo studies, the percent bone volume value of n-TiO2/PEEK was approximately twice as large as that of PEEK (P < 0.05). Vivid three-dimensional and histologic images of the newly generated bone on the implants further supported our test results. Conclusion Our study demonstrates that n-TiO2 significantly improves the bioactivity of PEEK, especially if it has a rough composite surface. A n-TiO2/PEEK composite with a rough surface could be a novel alternative implant material for orthopedic and dental applications. PMID:22419869

  8. 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.

  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. Effect of PTFE addition on the transfer film, wear and friction of PEEK-CuO composite

    SciTech Connect

    Vande Voort, J.; Bahadur, S.

    1995-12-31

    This work was done in part as a follow-up of an earlier study which had showed that CuO was effective in reducing the wear of PEEK, but the coefficient of friction of PEEK increased with the addition of CuO. In order to reduce the coefficient of friction, the organic filler PTFE was added to the CUO-PEEK composite so as to increase its appeal for practical applications. Initially, the optimum volume fraction of CuO in PEEK was determined for minimum wear by varying the proportion of the inorganic filler. With this composition as the basis for total filler content, PTFE was added to CuO-filled composites in 5 and 10 vol.% proportions. The friction and wear behaviors of these composites sliding against a tool steel surface were studied in a pin-on-disk configuration. It was determined from experiment that the optimum filler proportion of CuO in PEEK for minimum wear rate was 35 vol.%. The greater the content of CuO, the higher was the coefficient of friction. The optimum composition with PTFE and Cu additions was PEEK-30 vol.% CuO-5 vol.% PTFE. The wear rate and the coefficient of friction both of these compositions were lower than those of PEEK-35 vol.% CuO. The wear behavior has been analyzed by optical and scanning electron microscopy in terms of the ability of these composites to form transfer film on the steel counterface and the transfer film of PEEK-CuO-PTFE formulation has been investigated by XPS analysis. The XPS results revealed the presence of Cu ions and FeF{sub 2} compounds near the interface of the transfer film and the steel substrate. These observations have been used to support the hypothesis of reduced wear by the addition of inorganic and organic fillers to the polymer material.

  11. Cervical Cancer Screening

    MedlinePlus

    ... Cancer found early may be easier to treat. Cervical cancer screening is usually part of a woman's health ... may do more tests, such as a biopsy. Cervical cancer screening has risks. The results can sometimes be ...

  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. The synthesis of poly(ether ether ketone) (PEEK) derived from 1,1-bis(4-hydroxyphenyl)-1-phenyl-2,2,3,3,4,4,4-heptafluorobutane

    SciTech Connect

    Peterman, J.A.; Feld, W.A.

    1995-12-31

    Poly(ether ether ketone)s (PEEK) are of interest due to their high thermal stability. Most PEEK materials are prepared by aromatic nucleophilic substitution between an activated aromatic dihalide and an alkali-metal bisphenolate in polar, aprotic solvents. We now report the preparation of a PEEK containing an extended fluorocarbon chain in the bisphenol, analogous to that produced by McGrath, et. al which contained a trifluoromethyl group in the bisphenol, and examine the effect on thermal properties.

  14. 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

  15. Veliparib, Topotecan Hydrochloride, and Filgrastim or Pegfilgrastim in Treating Patients With Persistent or Recurrent Cervical Cancer

    ClinicalTrials.gov

    2016-03-25

    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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. Investigations of the mechanical behavior of graphite/PEEK (APC-2) composites

    SciTech Connect

    Lee, K.

    1991-01-01

    The purpose was to investigate the effects of two phenomena specific to thermoplastic resin composites. These phenomena are: (a) significant nonlinear creep, that occurs especially at high temperatures, which affects the residual thermal stresses in a geometrically constrained structure; and (b) spatially nonuniform transverse crystallinity that develops in some fiber-reinforced thermoplastic composites, which introduces spatial variability and nonlinearity in the stiffness of the composite. The first part is related to (a). It presents a computational scheme for the optimal temperature path for APC-2 composite laminate, modeled as nonlinear, thermorheologically complex, viscoelastic material. The laminate is assumed to be sufficiently thin to obviate accounting for temperature nonuniformities across the thickness. The second part concerns (b) and presents analytical/computational results for the in-plane stresses in a moderately thick, cross-ply, graphite/PEEK (APC-2) laminate accounting for effects of nonuniform PEEK crystallinity across the plate's thickness.

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

    PubMed

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

    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

  2. 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.

  3. 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. PMID:27286776

  4. Characterization of elastic-plastic and viscoplastic behavior of AS4/PEEK thermoplastic composite

    SciTech Connect

    Yoon, Kwangjoon.

    1990-01-01

    The elastic-plastic and strength properties of AS4/PEEK (APC-2) thermoplastic composite were characterized with respect to temperature variation by using a one parameter plasticity model and the elastic-viscoplastic properties were characterized by using a one parameter overstress viscoplasticity model and a modified Bodner and Patom's viscoplasticity model. These plasticity and viscoplasticity models were verified further for the case of unidirectional composite panels with cutouts and in laminates with and without hole.

  5. FDG and FMISO PET Hypoxia Evaluation in Cervical Cancer

    ClinicalTrials.gov

    2015-06-03

    Cervical Adenocarcinoma; Cervical Squamous Cell Carcinoma; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer; Stage IVB Cervical Cancer

  6. 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

  7. Derivation of cesium-137 residual radioactive material guidelines for the Peek Street site, Schenectady, New York

    SciTech Connect

    Jones, L.; Nimmagadda, M.; Yu, C.

    1992-01-01

    Residual radioactive material guidelines for cesium-137 were derived for the Peek rk. The derivation was based on the requirement that the Street site in Schenectady, New York. The derivation was based on the requirement that the 50-year committed effective dose equivalent to a hypothetical individual who lives or works in the immediate vicinity of the Peek Street site should not exceed a dose of 100 mrem/yr following remedial action. The US Department of Energy (DOE) residual radioactive material guideline computer code, RESRAD was used in this evaluation. Three potential scenarios were considered for the site on the assumption that for a period of 1,000 years following remedial action, the site wig be utilized without radiological restrictions. The scenarios vary with regard to use of the site, time spent at the site, and sources of food consumed. Results indicate that the basic dose limit of 100 mrem/yr will not be exceeded for cesium-137 within 1,000 years, provided that the soil concentration of cesium-137 at the Peek Street site does not exceed the following levels: 98 pCi/g for Scenario A (industrial worker: the expected scenario), 240 pCi/g for Scenario B (recreationist: a plausible scenario), and 34 pCi/g for Scenario C (resident farmer ingesting food produced in the decontaminated area: a plausible scenario).

  8. 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.

  9. The Comprehensive Biomechanics and Load-Sharing of Semirigid PEEK and Semirigid Posterior Dynamic Stabilization Systems

    PubMed Central

    Sengupta, D. K.; Bucklen, Brandon; McAfee, Paul C.; Nichols, Jeff; Angara, Raghavendra; Khalil, Saif

    2013-01-01

    Alternatives to conventional rigid fusion have been proposed for several conditions related to degenerative disc disease when nonoperative treatment has failed. Semirigid fixation, in the form of dynamic stabilization or PEEK rods, is expected to provide compression under loading as well as an intermediate level of stabilization. This study systematically examines both the load-sharing characteristics and kinematics of these two devices compared to the standard of internal rigid fixators. Load-sharing was studied by using digital pressure films inserted between an artificially machined disc and two loading fixtures. Rigid rods, PEEK rods, and the dynamic stabilization system were inserted posteriorly for stabilization. The kinematics were quantified on ten, human, cadaver lumbosacral spines (L3-S1) which were tested under a pure bending moment, in flexion-extension, lateral bending, and axial rotation. The magnitude of load transmission through the anterior column was significantly greater with the dynamic device compared to PEEK rods and rigid rods. The contact pressures were distributed more uniformly, throughout the disc with the dynamic stabilization devices, and had smaller maximum point-loading (pressures) on any particular point within the disc. Kinematically, the motion was reduced by both semirigid devices similarly in all directions, with slight rigidity imparted by a lateral interbody device. PMID:23984077

  10. Damage tolerance evaluation of PEEK (polyether ether ketone) composites: Final report

    SciTech Connect

    Frazier, J.L.

    1988-12-01

    A polyether ether ketone (PEEK) thermoplastic system is currently being evaluated in flight service as a structural element for the US Air Force C-130 transport plane. The particular structure under study is the C-130 belly skin, a fuselage panel that is located on the underside of the aircraft and is subjected to impact from runway debris. A current Air Force objective is to reduce maintenance and replacement requirements of aircraft using lightweight composite structures to replace or supplement existing metal alloy components. The incorporation of lighter weight composite structures would result in aircraft weight reductions, allowing greater range and fuel economy. The impact-damage susceptibility of composite structures often results in strain-limited application of composite materials where the mechanical properties' advantages over traditional metal alloys are not attained. Methods developed to enhance the damage tolerance of composite material systems should increase their potential uses in existing and future aircraft. A materials evaluation program was conducted to determine the possible benefits of interleaving thermoplastic film layers between the plies of a PEEK/graphite composite material system to produce a material system with increased resistance to impact damage. Several laminate designs incorporating PEEK thermoplastic film as an interleaf material were subjected to impacts of various energies and projectile velocities. Mechanical properties of unimpacted, open-hole, and impacted laminate panels were measured to determine the effectiveness of the interleaf concept for improving damage tolerance relative to the existing baseline material. 5 refs., 19 figs., 8 tabs.

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

    PubMed

    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

  12. 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

  13. Drugs Approved for Cervical Cancer

    MedlinePlus

    ... Professionals Questions to Ask about Your Treatment Research Drugs Approved for Cervical Cancer This page lists cancer ... in cervical cancer that are not listed here. Drugs Approved to Prevent Cervical Cancer Cervarix (Recombinant HPV ...

  14. Cervical cancer - screening and prevention

    MedlinePlus

    Cancer cervix - screening; HPV - cervical cancer screening; Dysplasia - cervical cancer screening ... Almost all cervical cancers are caused by HPV (human papilloma virus). HPV is a common virus that spreads through sexual contact. Certain types ...

  15. Cervical insufficiency and cervical cerclage.

    PubMed

    Brown, Richard; Gagnon, Robert; Delisle, Marie-France; Gagnon, Robert; Bujold, Emmanuel; Basso, Melanie; Bos, Hayley; Brown, Richard; Cooper, Stephanie; Crane, Joan; Davies, Gregory; Gouin, Katy; Menticoglou, Savas; Mundle, William; Pylypjuk, Christy; Roggensack, Anne; Sanderson, Frank; Senikas, Vyta

    2013-12-01

    Objectif : La présente directive clinique a pour but de fournir un cadre de référence que les cliniciens pourront utiliser pour identifier les femmes qui sont exposées aux plus grands risques de connaître une insuffisance cervicale, ainsi que pour déterminer les circonstances en présence desquelles la mise en place d’un cerclage pourrait s’avérer souhaitable. Résultats : La littérature publiée a été récupérée par l’intermédiaire de recherches menées dans PubMed ou MEDLINE, CINAHL et The Cochrane Library en 2012 au moyen d’un vocabulaire contrôlé (p. ex. « uterine cervical incompetence ») et de mots clés appropriés (p. ex. « cervical insufficiency », « cerclage », « Shirodkar », « cerclage », « MacDonald », « cerclage », « abdominal », « cervical length », « mid-trimester pregnancy loss »). Les résultats ont été restreints aux analyses systématiques, aux essais comparatifs randomisés / essais cliniques comparatifs et aux études observationnelles. Aucune restriction n’a été appliquée en matière de date ou de langue. Les recherches ont été mises à jour de façon régulière et intégrées à la directive clinique jusqu’en janvier 2011. La littérature grise (non publiée) a été identifiée par l’intermédiaire de recherches menées dans les sites Web d’organismes s’intéressant à l’évaluation des technologies dans le domaine de la santé et d’organismes connexes, dans des collections de directives cliniques, dans des registres d’essais cliniques et auprès de sociétés de spécialité médicale nationales et internationales. Valeurs : La qualité des résultats est évaluée au moyen des critères décrits dans le rapport du Groupe d’étude canadien sur les soins de santé préventifs (Tableau). Recommandations 1. Les femmes qui sont enceintes ou qui planifient connaître une grossesse devraient faire l’objet d’une évaluation visant les facteurs de

  16. Preventing cervical cancer globally.

    PubMed

    Schmeler, Kathleen M

    2012-11-01

    Cervical cancer is one of the leading causes of cancer and cancer-related deaths among women worldwide. More than 85% of cases and deaths occur in the developing world where the availability of effective screening is limited. In this issue of the journal, Pierce and colleagues (beginning on page 1273) describe a novel technique using a high-resolution microendoscope (HRME) to diagnose cervical dysplasia. This perspective reviews the limitations of existing cervical cancer screening methods currently in use in low-resource settings and the potential for HRME imaging to contribute to cervical cancer prevention in the developing world.

  17. 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.

  18. 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

  19. 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.

  20. Spontaneous delivery through a cervical tear without cervical os dilatation.

    PubMed

    Djokovic, Dusan; Costa, Cristina; Martins, Ana; Abushad, Shadi

    2015-01-01

    Spontaneous delivery through a cervical tear, provoked by prostaglandin-induced uterine contractions, was described in a G2P0 woman with a history of cervical dilatation and uterine curettage. This rare complication with potentially serious maternal-fetal consequences can be predicted by an aberrant cervical response to prostaglandins in parturients with previous cervical interventions. PMID:25678963

  1. Spontaneous delivery through a cervical tear without cervical os dilatation

    PubMed Central

    Djokovic, Dusan; Costa, Cristina; Martins, Ana; Abushad, Shadi

    2015-01-01

    Key Clinical Message Spontaneous delivery through a cervical tear, provoked by prostaglandin-induced uterine contractions, was described in a G2P0 woman with a history of cervical dilatation and uterine curettage. This rare complication with potentially serious maternal–fetal consequences can be predicted by an aberrant cervical response to prostaglandins in parturients with previous cervical interventions. PMID:25678963

  2. Cervical Discitis in Children.

    PubMed

    Scheuerman, Oded; Landau, Daniel; Schwarz, Michael; Hoffer, Vered; Marcus, Nufar; Hoffnung, Liat Ashkenazi; Levy, Itzhak

    2015-07-01

    Cervical discitis, though rare, should be included in the differential diagnosis of torticollis, neck pain and neurodevelopmental regression in motor skills in children and infants. Magnetic resonance imaging is the diagnostic method of choice. Treatment should be conservative with antibiotics only. The aim of this study was to describe the 10-year experience of a tertiary pediatric medical center with cervical discitis. PMID:25886786

  3. 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.

  4. 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.

  5. Shear strains in a graphite-PEEK beam by moire interferometry with carrier fringes

    NASA Technical Reports Server (NTRS)

    Post, Daniel; Czarnek, Robert; Joh, Duksung

    1986-01-01

    A multispan quasi-isotropic graphite-PEEK beam exhibited dramatic shear strains in the interlaminar region between plies. Shear strains in the plies themselves varied in basic accord with fiber direction. Large anomalous shear strains developed near the center of the beam height, where shear stresses were large. High-sensitivity moire interferometry with 2400 lines/mm was used. A new technique of data extraction was developed, using carrier fringes to transform the pattern to one in which fringe slopes are proportional to derivatives of displacement. It enhanced detection and measurement of highly localized shear-strain gradients.

  6. Response of notched AS4/PEEK laminates to tension/compression loading

    NASA Technical Reports Server (NTRS)

    Simonds, Robert A.; Stinchcomb, Wayne W.

    1989-01-01

    Fatigue life, damage-initiation and propagation, and residual strength data are presently examined to ascertain the response of notched AS4/PEEK specimens to fully reversed tension/compression loading. Stiffness measurements made during the low-level fatigue history show that compression stiffness and tension stiffness degrade throughout the fatigue life. Damage to specimens fatigued at higher cyclic stresses developed primarily in the direction perpendicular to the loading. As in the case of specimens fatigued at lower stress levels, residual compressive stress decreased with damage development.

  7. 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.

  8. 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.

  9. 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.

  10. Temperature rise due to mechanical energy dissipation in undirectional thermoplastic composites(AS4/PEEK)

    NASA Technical Reports Server (NTRS)

    Georgious, I. T.; Sun, C. T.

    1992-01-01

    The history of temperature rise due to internal dissipation of mechanical energy in insulated off-axis uniaxial specimens of the unidirectional thermoplastic composite (AS4/PEEK) has been measured. The experiment reveals that the rate of temperature rise is a polynomial function of stress amplitude: It consists of a quadratic term and a sixth power term. This fact implies that the specific heat of the composite depends on the stretching its microstructure undergoes during deformation. The Einstein theory for specific heat is used to explain the dependence of the specific heat on the stretching of the microstructure.

  11. Mode II interlaminar fracture of graphite/epoxy and graphite/PEEK

    NASA Technical Reports Server (NTRS)

    Carlsson, L. A.; Gillespie, J. W.; Trethewey, B. R.

    1986-01-01

    The end notched flexure (ENF) specimen is employed in an investigation of the interlaminar fracture toughness in Mode II (skew symmetric shear) loading of unidirectional graphite/epoxy and graphite/PEEK composites. Important experimental parameters such as the influence of precracking and the data reduction scheme for the Mode II toughness are discussed. Nonlinear load-deflection response is significant for the tough thermoplastic resin composite but is also present for the brittle thermoset composite. The observed nonlinearities, which are highly rate dependent, are attributed to a combination of slow stable crack growth preceding unstable crack growth and material inelastic behavior in the process zone around the crack tip.

  12. MRI and PET Imaging in Predicting Treatment Response in Patients With Stage IB-IVA Cervical Cancer

    ClinicalTrials.gov

    2016-06-24

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma; Cervical Undifferentiated Carcinoma; Recurrent Cervical Carcinoma; Stage IB2 Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage IIIA Cervical Cancer; Stage IIIB Cervical Cancer; Stage IVA Cervical Cancer

  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. PMID:16410639

  14. The Effect of Surface Chemistry and Morphology on the Properties of HVAF PEEK Single Splats

    NASA Astrophysics Data System (ADS)

    Withy, B. P.; Hyland, M. M.; James, B. J.

    2008-12-01

    Thermal spray of polymers has had limited investigation due to the narrow processing windows that are inherent to polymer powders, especially their low temperatures of thermal degradation. The polymer poly aryl ether ether ketone (PEEK) has a continuous use temperature of 260 °C, does not suffer significant thermal degradation below 500 °C (Lu et al., Polymer, 37(14):2999-3009, 1996), and has high resistance to alkaline and acidic attack. These properties led to PEEK being selected for investigation. To minimize thermal degradation of the particles, the high velocity air fuel technique was used. To investigate the effect of substrate pretreatment on single splat properties, single splats were collected on aluminum 5052 substrates with six different pretreatments. The single splats collected were imaged by scanning electron microscopy and image analysis was performed with ImageJ, an open source scientific graphics package. On substrates held at 323 °C, it was found that substrate pretreatment had a significant effect on the circularity and area of single splats, and also on the number of splats deposited on the substrates. Increases in splat circularity, area, and the number of splats deposited on the surface were linked to the decrease in chemisorbed water on the substrate surface and the decrease of surface roughness. This proved that surface chemistry and roughness are crucial to forming single splats with good properties, which will lead to coatings of good properties.

  15. 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.

  16. 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.

  17. On the thermally-induced residual stresses in thick fiber-thermoplastic matrix (PEEK) cross-ply laminated plates

    SciTech Connect

    Hu, S.; Nairn, J.A.

    1992-09-01

    An analytical method for calculating thermally-induced residual stresses in laminated plates is applied to cross-ply PEEK laminates. The authors 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.

  18. [Cervical cerclage in 2008].

    PubMed

    Fuchs, F; Senat, M-V; Gervaise, A; Deffieux, X; Faivre, E; Frydman, R; Fernandez, H

    2008-11-01

    Cervical cerclage is a common surgical technique that has been used for more than 50 years to prevent preterm deliveries and in the management of a threatened second trimester loss. However, it remains one of the most controversial interventions in obstetrics and this is probably due to difficulties in diagnosing cervical insufficiency, which is based on a history of recurrent second trimester loss or early preterm delivery following painless cervical dilatation in the absence of contractions or bleeding. This article reviews in 2008 the current literature regarding the efficacy of elective cerclage, ultrasound-indicated cerclage, emergency cerclage, and cervico-isthmic cerclage for singletons and multiple pregnancies.

  19. [Cervical cerclage in 2008].

    PubMed

    Fuchs, F; Senat, M-V; Gervaise, A; Deffieux, X; Faivre, E; Frydman, R; Fernandez, H

    2008-11-01

    Cervical cerclage is a common surgical technique that has been used for more than 50 years to prevent preterm deliveries and in the management of a threatened second trimester loss. However, it remains one of the most controversial interventions in obstetrics and this is probably due to difficulties in diagnosing cervical insufficiency, which is based on a history of recurrent second trimester loss or early preterm delivery following painless cervical dilatation in the absence of contractions or bleeding. This article reviews in 2008 the current literature regarding the efficacy of elective cerclage, ultrasound-indicated cerclage, emergency cerclage, and cervico-isthmic cerclage for singletons and multiple pregnancies. PMID:18922730

  20. Prevent Cervical Cancer

    MedlinePlus

    ... Fighting Cervical Cancer Worldwide Stay Informed Printable Versions Standard quality PDF [PDF-877KB] High-quality PDF for professional ... uterus, vagina, and vulva. Stay Informed Printable Versions Standard quality PDF [PDF-877KB] High-quality PDF for professional ...

  1. 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 ( ...

  2. 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.

  3. 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

  4. Pseudoactinomyces in cervical mucus.

    PubMed

    Deen, Suha; Ashford, Keith; Harwood, Andrew; Gray, Trevor

    2011-05-01

    Actinomyces israelii are gram-positive filamentous bacteria forming yellow sulfur granules. They are the most well known complication of intrauterine contraceptive devices (IUCD). Healthcare staff dealing with reporting cervical smears should be aware of pseudoactinomyces entity in a cervical smears and biopsies as it may raise a false alarm to the clinician and may lead to unnecessary removal of IUCD and/or medical treatment.

  5. Postlaminectomy cervical deformity.

    PubMed

    Deutsch, Harel; Haid, Regis W; Rodts, Gerald E; Mummaneni, Praveen V

    2003-09-15

    Postlaminectomy cervical kyphosis is an important consideration when performing surgery. Identifying factors predisposing to postoperative deformity is essential. The goal is to prevent postlaminectomy cervical kyphosis while exposing the patient to minimal additional morbidity. When postlaminectomy kyphosis does occur, surgical correction is often required and performed via an anterior, posterior, or combined approach. The authors discuss the indications for surgical approaches as well as clinical results. PMID:15347223

  6. Atezolizumab and Bevacizumab in Treating Patients With Recurrent, Persistent, or Metastatic Cervical Cancer

    ClinicalTrials.gov

    2016-10-10

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma, Not Otherwise Specified; Recurrent Cervical Carcinoma; Stage IVA Cervical Cancer; Stage IVB Cervical Cancer

  7. Nivolumab in Treating Patients With Persistent, Recurrent, or Metastatic Cervical Cancer

    ClinicalTrials.gov

    2016-11-01

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma, Not Otherwise Specified; Recurrent Cervical Carcinoma; Stage IVA Cervical Cancer; Stage IVB Cervical Cancer

  8. 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.

  9. Fatigue data for polyether ether ketone (PEEK) under fully-reversed cyclic loading

    PubMed Central

    Shrestha, Rakish; Simsiriwong, Jutima; Shamsaei, Nima

    2016-01-01

    In this article, the data obtained from the uniaxial fully-reversed fatigue experiments conducted on polyether ether ketone (PEEK), a semi-crystalline thermoplastic, are presented. The tests were performed in either strain-controlled or load-controlled mode under various levels of loading. The data are categorized into four subsets according to the type of tests, including (1) strain-controlled fatigue tests with adjusted frequency to obtain the nominal temperature rise of the specimen surface, (2) strain-controlled fatigue tests with various frequencies, (3) load-controlled fatigue tests without step loadings, and (4) load-controlled fatigue tests with step loadings. Accompanied data for each test include the fatigue life, the maximum (peak) and minimum (valley) stress–strain responses for each cycle, and the hysteresis stress–strain responses for each collected cycle in a logarithmic increment. A brief description of the experimental method is also given. PMID:26937465

  10. 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.

  11. Damage extension in carbon fiber/PEEK crossply laminates under low velocity impact

    SciTech Connect

    Wang, H.; Vu-khanh, T.

    1994-12-31

    Low-velocity impact in carbon fiber/PEEK crossply laminates has been studied by test and analysis. Emphases of the study were focused on the material properties which may control the damage extension of transverse crack and delamination. It was found that, considering the thermal residual stress and the crack constraining effect, extension of transverse cracks could not be predicted by the Strength of Materials approach. The impact-induced delamination could be characterized by the crack arrest concept of fracture mechanics. The delamination resulted from a Mode II-dominated unstable fracture, which occurred under displacement-controlled conditions and seemed to be arrested at a constant interlaminar fracture energy. 44 refs.

  12. A constitutive model for AS4/PEEK thermoplastic composites under cyclic loading

    NASA Technical Reports Server (NTRS)

    Rui, Yuting; Sun, C. T.

    1990-01-01

    Based on the basic and essential features of the elastic-plastic response of the AS4/PEEK thermoplastic composite subjected to off-axis cyclic loadings, a simple rate-independent constitutive model is proposed to describe the orthotropic material behavior for cyclic loadings. A one-parameter memory surface is introduced to distinguish the virgin deformation and the subsequent deformation process and to characterize the loading range effect. Cyclic softening is characterized by the change of generalized plastic modulus. By the vanishing yield surface assumption, a yield criterion is not needed and it is not necessary to consider loading and unloading separately. The model is compared with experimental results and good agreement is obtained.

  13. Fatigue data for polyether ether ketone (PEEK) under fully-reversed cyclic loading.

    PubMed

    Shrestha, Rakish; Simsiriwong, Jutima; Shamsaei, Nima

    2016-03-01

    In this article, the data obtained from the uniaxial fully-reversed fatigue experiments conducted on polyether ether ketone (PEEK), a semi-crystalline thermoplastic, are presented. The tests were performed in either strain-controlled or load-controlled mode under various levels of loading. The data are categorized into four subsets according to the type of tests, including (1) strain-controlled fatigue tests with adjusted frequency to obtain the nominal temperature rise of the specimen surface, (2) strain-controlled fatigue tests with various frequencies, (3) load-controlled fatigue tests without step loadings, and (4) load-controlled fatigue tests with step loadings. Accompanied data for each test include the fatigue life, the maximum (peak) and minimum (valley) stress-strain responses for each cycle, and the hysteresis stress-strain responses for each collected cycle in a logarithmic increment. A brief description of the experimental method is also given. PMID:26937465

  14. The effect of thermal processing on residual strain development in unidirectional graphite fibre reinforced PEEK

    SciTech Connect

    Unger, W.J.; Hansen, J.S. )

    1993-01-01

    The effect of annealing on residual strain development in amorphous graphite fiber reinforced PEEK (APC-2) is studied experimentally. A method is presented for embedding strain gauges in a unidirectional laminate at the time of manufacture and then quenching the laminate into the amorphous state. With this method, thermal and crystallization strains are measured directly during quasi-isothermal heating of the laminate. Both longitudinal and transverse lamina strains resulting from contraction during crystallization are measured. Longitudinal cyrstallization strains are found to be negligible due to fiber stiffness. Transverse contraction due to crystallization is large and increases with anneal temperature. A coefficient of crystalline expansion is defined which is analogous to the CTE. This coefficient describes the permanent crystallization strain as a function of anneal temperature and is determined experimentally. 26 refs.

  15. 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 ...

  16. 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. PMID:26878769

  17. 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.

  18. 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

  19. Free volume study on the miscibility of PEEK/PEI blend using positron annihilation and dynamic mechanical thermal analysis

    NASA Astrophysics Data System (ADS)

    Ramani, R.; Alam, S.

    2015-06-01

    High performance polymer blend of poly(ether ether ketone) (PEEK) and poly(ether imide) (PEI) was examined for their free volume behaviour using positron annihilation lifetime spectroscopy and dynamic mechanical thermal analysis methods. The fractional free volume obtained from PALS shows a negative deviation from linear additivity rule implying good miscibility between PEEK and PEI. The dynamic modulus and loss tangent were obtained for the blends at three different frequencies 1, 10 and 100 Hz at temperatures close to and above their glass transition temperature. Applying Time-Temperature-Superposition (TTS) principle to the DMTA results, master curves were obtained at a reference temperature To and the WLF coefficients c01 and c02 were evaluated. Both the methods give similar results for the dependence of fractional free volume on PEI content in this blend. The results reveal that free volume plays an important role in determining the visco-elastic properties in miscible polymer blends.

  20. 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.

  1. Ovarian and cervical cancer.

    PubMed Central

    Williams, C.

    1992-01-01

    Death rates from cervical cancer have already fallen this century and for patients with invasive cervical cancer five year survival rates are greater than for most solid tumours. Better screening for premalignant changes may further reduce the incidence of invasive cancer; indeed, it has been claimed that the reduction in mortality could be as high as 90%, though estimates of screening efficacy have varied greatly. For those with advanced invasive carcinoma neoadjuvant chemotherapy may reduce the risk of relapse and improve survival. Images FIG 2 p1504-a PMID:1611377

  2. 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.

  3. 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. PMID:26462678

  4. 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. PMID:26849309

  5. 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.

  6. 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

  7. Chemoradiation Therapy and Ipilimumab in Treating Patients With Locally Advanced Cervical Cancer

    ClinicalTrials.gov

    2016-10-25

    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 IIIB Cervical Cancer; Stage IVA Cervical Cancer

  8. Cervical Neoplasia Probe Control

    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)

  9. 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

  10. Congenital Midline Cervical Cleft

    PubMed Central

    Villanueva-Meyer, Javier; Glastonbury, Christine; Marcovici, Peter

    2015-01-01

    Congenital midline cervical cleft is a rare anomaly that typically presents in the neonatal period as a thin suprasternal vertical band of erythematous skin with a nipple-like projection superiorly, which may exude fluid. We present the clinical and pathophysiologic features and the imaging findings of this uncommon, and rarely described entity in a newborn girl. PMID:25926928

  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

    2016-03-16

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma; 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. Clinical aspects of cervical insufficiency.

    PubMed

    Lotgering, Frederik K

    2007-06-01

    Fetal loss is a painful experience. A history of second or early third trimester fetal loss, after painless dilatation of the cervix, prolapse or rupture of the membranes, and expulsion of a live fetus despite minimal uterine activity, is characteristic for cervical insufficiency. In such cases the risk of recurrence is high, and a policy of prophylactic cerclage may be safer than one of serial cervical length measurements followed by cerclage, tocolysis and bed rest in case of cervical shortening or dilatation. In low risk cases, however, prophylactic cerclage is not useful. There is a need for more basic knowledge of cervical ripening, objective assessment of cervical visco-elastic properties, and randomized controlled trials of technical aspects of cervical cerclage (e.g. suturing technique).

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Retention force of differently fabricated telescopic PEEK crowns with different tapers.

    PubMed

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

    2016-01-01

    To assess the retention force between primary and secondary PEEK crowns made by different fabrication methods. Primary crowns with different tapers (0°, 1°, and 2°) were fabricated and secondary crowns that were either milled from breCam BioHPP blanks, pressed from pellets (BioHPP Pellet) or granules (BioHPP Granulat) were produced. Each specimen was measured 20 times in a pulloff-test and results were analyzed using 2-/1-way ANOVA and linear regression analyses (p<0.05). Within 0° tapered crowns milled secondary crowns showed lower retention forces compared to pressed pellet crowns. Crowns with a 1° taper, however, showed no impact of the fabrication method on retention force. At a 2° taper, granular pressed crowns displayed lower values than their milled counterparts. Within the milled group, a 0° taper showed lower retention values than the higher tapers, whereas in the pressed groups, no impact of taper angle on retention force was found. PMID:27477224

  20. Composite S-PEEK membranes for medium temperature polymer electrolyte fuel cells

    NASA Astrophysics Data System (ADS)

    Carbone, A.; Pedicini, R.; Saccà, A.; Gatto, I.; Passalacqua, E.

    Sulphonated-PEEK polymers with two different sulphonation degrees (DS) were obtained by varying the sulphonation parameters. Ionomeric membranes were prepared as a reference. Composite membranes were obtained by mixing different percentage of 3-aminopropyl functionalised silica to the polymers dissolved in DMAc. The resulting membranes were characterised in terms of water uptake, IEC and proton conductivity in different conditions of temperature and relative humidity. The introduction of amino-functionalised silica in the lowest DS polymer slightly increases the water uptake, because it retains the water and in this case the hydrophilic property of the material is predominant. In the highest DS polymer the presence of SiO-NH 2 decreases the water uptake and swelling, probably due to a major interaction between the amino groups of silica and the sulphonic groups of polymer. The proton conductivity of the highly sulphonated polymer does not change even if the swelling decreases, while in the poorly sulphonated polymer a slight increases of water retention increases the conductivity. A composite membrane was tested in PEFC at 120 °C reaching a maximum power density of 246 mW cm -2.

  1. Adenocarcinoma of the cervical stump

    SciTech Connect

    Goodman, H.M.; Niloff, J.M.; Buttlar, C.A.; Welch, W.R.; Marck, A.; Feuer, E.J.; Lahman, E.A.; Jenison, E.; Knapp, R.C. )

    1989-11-01

    Sixteen women with adenocarcinoma of the cervical stump were treated over a 15-year period. The median survivals of 40 months for stage IB and 17 months for stages II and III were significantly worse compared with those for patients treated for cervical adenocarcinoma of the intact uterus or squamous carcinoma of the cervical stump. The poor results were due to both local and distant failure. Implications regarding tumor radiosensitivity and adjuvant therapy in these high-risk patients are discussed.

  2. Operations for cervical incompetence.

    PubMed

    Branch, D W

    1986-06-01

    At present, cervical cerclage is indicated in those patients with a classic history of cervical incompetence. For the majority of these patients, a postconceptional cerclage procedure is better suited because it is done after the fetus has been evaluated ultrasonographically for obvious abnormalities and after the risk for spontaneous abortion is past. The greatest experience is with the Shirodkar and the McDonald procedures; allowing for operator differences, neither appears to have an important advantage. The transabdominal cervicoisthmic cerclage may be a useful postconceptional procedure in the selected patient whose cervix is either markedly foreshortened, deeply lacerated, or infected. Preconceptional cerclages are best reserved for those rare patients in whom a markedly foreshortened incompetent cervix is associated with early second-trimester pregnancy losses (preconceptional isthmic cerclage) or in whom the cervix has a single, identifiable scar or deep laceration extending through the internal os (Lash procedure). PMID:3522005

  3. Degenerative cervical myelopathy.

    PubMed

    Kato, So; Fehlings, Michael

    2016-09-01

    Cervical myelopathy is the most common cause of acquired spinal cord compromise. The concept of degenerative cervical myelopathy (DCM), defined as symptomatic myelopathy associated with degenerative arthropathic changes in the spine axis, is being introduced. Given its progressive nature, treatment options have to be chosen in a timely manner. Surgical options include anterior discectomy and fusion (ACDF), anterior corpectomy and fusion (ACCF), arthroplasty (in highly select cases), posterior laminectomy with/without fusion, and laminoplasty. Indications for each should be carefully considered in individual patients. Riluzole, a sodium-glutamate antagonist, is a promising option to optimize neurologic outcomes post-surgery and is being examined in the CSM-Protect Randomized Controlled Trial. Preoperative risk assessment is mandatory for prognostication. Sagittal alignment is known to play an important role to optimize surgical outcome. Guidelines for optimal management of DCM are in process. In principle, all but the mildest cases of DCM should be offered surgery for optimal outcome. PMID:27250040

  4. [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.

  5. [Cervical disc herniation].

    PubMed

    Schnake, K J; Hoffmann, C-H; Kandziora, F

    2012-12-01

    The cervical disc herniation is characterized by prolapsed nucleus pulposus material through the annulus into the spinal canal. The local mechanical or chemical irritation of neural structures typically leads to symptoms of radiculopathy, cervicocephalgia or myelopathy. Pronounced sensorimotor deficits or intractable pain constitute surgical treatment. In all other cases conservative treatment is indicated, including pain medication, active and passive physiotherapy, and local injections, respectively. Anterior cervical discectomy and interbody fusion (ACDF) is still the surgical treatment of choice. Predominantly, cages with or without plates are in use to obtain solid fusion. The implantation of a total disc replacement is a viable alternative, if no contraindications exist. Other surgical techniques may be performed in proper selected cases. The overall clinical and radiological results of both surgical and conservative treatment are good. PMID:23296562

  6. [Preventing cervical cancer].

    PubMed

    Simon, P; Noël, J-C

    2015-09-01

    The incidence of cervical cancer has hopefully been dropping down in our industrialized countries since the introduction of both primary and secondary prevention. Nevertheless, it is still lethal in one out of two affected women though the introduction of cytological screening has dramatically reduced the mortality. Progressive diffusion of anti-HPV vaccination, the broadening of the viral types concerned, its association with existing screening measures and finally the introduction of viral detection as a screening tool must optimize the results already obtained.

  7. Asymptomatic cervical bruits.

    PubMed Central

    Côté, R.; Battista, R. N.

    1984-01-01

    The diagnosis, significance and management of asymptomatic cervical bruits have been the focus of considerable controversy. The literature does not support an aggressive approach but, rather, careful follow-up of patients with this disorder. This paper reviews the available data and discusses the management options of family practitioners who may detect this disorder during a routine physical examination, during an examination prompted by an unrelated problem or preoperatively when elective surgery is being considered. PMID:6367922

  8. Cervical spondylosis. An update.

    PubMed Central

    McCormack, B M; Weinstein, P R

    1996-01-01

    Cervical spondylosis is caused by degenerative disc disease and usually produces intermittent neck pain in middle-aged and elderly patients. This pain usually responds to activity modification, neck immobilization, isometric exercises, and medication. Neurologic symptoms occur infrequently, usually in patients with congenital spinal stenosis. For these patients, magnetic resonance imaging is the preferred initial diagnostic study. Because involvement of neurologic structures on imaging studies may be asymptomatic, consultation with a neurologist is advised to rule out other neurologic diseases. In most cases of spondylotic radiculopathy, the results of conservative treatment are so favorable that surgical intervention is not considered unless pain persists or unless there is progressive neurologic deficit. If indicated, a surgical procedure may be done through the anterior or posterior cervical spine; results are gratifying, with long-term improvement in 70% to 80% of patients. Cervical spondylotic myelopathy is the most serious and disabling condition of this disease. Because many patients have nonprogressive minor impairment, neck immobilization is a reasonable treatment in patients presenting with minor neurologic findings or in whom an operation is contraindicated. This simple remedy will result in improvement in 30% to 50% of patients. Surgical intervention is indicated for patients presenting with severe or progressive neurologic deficits. Anterior cervical approaches are generally preferred, although there are still indications for laminectomy. Surgical results are modest, with good initial results expected in about 70% of patients. Functional outcome noticeably declines with long-term follow-up, which raises the question of whether, and how much, surgical treatment affects the natural course of the disease. Prospective randomized studies are needed to answer these questions. Images Figure 1. Figure 2. Figure 3. PMID:8855684

  9. 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

  10. [Ultrastructure of cervical mucus].

    PubMed

    Chretien, F C

    1973-09-01

    This discussion covers the chemical structure of cervical mucus, accepted thoeries of its ultrastructure, and the author's data from the scanning electron microscope. A theory of the ultrastructure of cervical mucus must explain how it can be viscous and hostile to sperm for most of the cycle, but elastic and arranged parallel to their upward migration at ovulation. Cervical mucus is a hydrogel with 2%-12% solid phase composed of glucoproteins, probably meshed noncovalently into protein chains, with oligosaccharide side chains ending in sialic acid. A popular thoery generated by nuclear magnetic resonnance studies suggests that there may be sheaves of fibers arranged into micelles, with transverse fibers forming a netwrok that enlarges at ovulation. The light microscope is useless for studying mucus structure, but transmission electron microscopes have tentatively verified this hypothesis. The author's work with the scanning electron microscope showed a tangled web of filaments approximately 500-750 Angstroms, 1000-1500 or 300-6000 Angstroms thick. Usually the margin of the specimen appeared thin, like a spider web, but the center appeared thick with open channels, like the skeleton of a sponge, with a secondary network at the level of the oblique and transverse fibers.

  11. 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

  12. Pallidal deep brain stimulation in patients with cervical dystonia and severe cervical dyskinesias with cervical myelopathy

    PubMed Central

    Krauss, J; Loher, T; Pohle, T; Weber, S; Taub, E; Barlocher, C; Burgunder, J

    2002-01-01

    Objectives: Surgical treatment of complex cervical dystonia and of cervical dyskinesias associated with cervical myelopathy is challenging. In this prospective study, the long term effect of chronic pallidal stimulation in cervical dystonia and on combining the technique with spinal surgery in patients with severe cervical dyskinesias and secondary cervical myelopathy is described. Methods: Eight patients with a history of chronic dystonia who did not achieve adequate benefit from medical treatment or botulinum toxin injection participated in the study. Five patients had complex cervical dystonia with tonic postures and phasic movements. Three patients had rapidly progressive cervical myelopathy secondary to severe cervical dyskinesias and dystonia in the context of a generalised movement disorder. Quadripolar electrodes were implanted in the posteroventral lateral globus pallidus internus with stereotactic CT and microelectrode guidance. In the three patients with secondary cervical myelopathy, spinal surgery was performed within a few weeks and included multilevel laminectomies and a four level cervical corporectomy with spinal stabilisation. Results: Improvement of the movement disorder was noted early after pallidal surgery, but the full benefit could be appreciated only with a delay of several months during chronic stimulation. Three months after surgery, patients with cervical dystonia had improved by 38% in the severity score, by 54% in the disability score, and by 38% in the pain score of a modified version of the Toronto western spasmodic torticollis rating scale. At a mean follow up of 20 months, the severity score had improved by 63%, the disability score by 69%, and the pain score by 50% compared with preoperatively. There was also sustained amelioration of cervical dyskinesias in the three patients who underwent spinal surgery. Lead fractures occurred in two patients. The mean amplitude needed for chronic deep brain stimulation was 3.8 V at a mean

  13. Cathodic delaminations of poly(phenyl ether ether ketone) (PEEK) coatings overlaid on zinc phosphate-deposited steels

    SciTech Connect

    Sugama, T.; Carciello, N.R. . Dept. of Applied Science)

    1993-12-10

    The melt-crystallized poly(phenyl) ether ether ketone (PEEK) polymer was overlaid on crystalline zinc phosphate (Zn [center dot] Ph) conversion coating-deposited and nondeposited cold-rolled steels at 400 C in air or in N[sub 2] environments. The ability of these coatings systems to protect the steel against corrosion was evaluated from the rate of cathodic delamination of the coating layer from the steel. Because the cathodic reaction, H[sub 2]O + 1/20[sub 2] + 2e[sup [minus

  14. 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.

  15. [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.

  16. [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. PMID:27606653

  17. 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.

  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. PMID:26366514

  19. Supplementary radiological and beryllium characterization of the facility at 425 Peek Street, Schenectady, New York

    SciTech Connect

    Foley, R.D.; Allred, J.F.; Carrier, R.F.

    1994-10-01

    At the request of the Office of Naval Reactors through the Office of Remedial Action and Waste Technology, a radiological survey of the Peek Street industrial facility, the adjacent state-owned bike path, and two nearby residential properties was conducted by Oak Ridge National Laboratory (ORNL) in November 1989. The results indicated small isolated areas that exceeded DOE guidelines. These areas totaled approximately 0.2 m{sup 2} of floor area and approximately 3 m{sup 2} of wall area inside the building, and two small areas totaling approximately 5 m{sup 2} outside the building. A small section of one of these areas extended beyond the fence on the east side of the industrial property onto the state-owned property. No residual radioactive material or elevated radiation levels were detected on any portion of the paved section of the bike path or the residential properties adjacent to the site. Because the elevated radiation levels were localized and limited in extent, any credible use scenario, including current use conditions, indicated that no significant radiation exposures would accrue to individuals frequenting the area. Samples were also analyzed for elemental beryllium since that material had formerly been used at the site. In conjunction with the planned remediation at the facility, a supplementary characterization survey was performed to further define the areas containing beryllium in excess of the identified guidelines. Additional radiological characterization of Ra-226, Th-232, and U-238 was also performed in areas that were largely inaccessible prior to the remediation efforts.

  20. Cervical incompetence: diagnosis and outcome.

    PubMed

    Barford, D A; Rosen, M G

    1984-08-01

    The results of 147 cervical cerclage procedures were reviewed in a retrospective study. Patient history and past reproductive performance were assessed to determine which factors were predictive of successful pregnancy outcome after cervical cerclage. A past history of spontaneous second trimester abortion or premature labor was associated with a better outcome than was a history classically associated with cervical incompetence. Morbidity immediately following the procedure was low, however significant morbidity related to cervical scarring occurred at the time of delivery. There was poor correlation between the clinical history, examination and adjunctive tests of cervical incompetence, and the pregnancy outcome following cerclage. These observations indicate the need for a prospective, randomized study of the efficacy of this procedure.

  1. The Biomechanics of Cervical Spondylosis

    PubMed Central

    Ferrara, Lisa A.

    2012-01-01

    Aging is the major risk factor that contributes to the onset of cervical spondylosis. Several acute and chronic symptoms can occur that start with neck pain and may progress into cervical radiculopathy. Eventually, the degenerative cascade causes desiccation of the intervertebral disc resulting in height loss along the ventral margin of the cervical spine. This causes ventral angulation and eventual loss of lordosis, with compression of the neural and vascular structures. The altered posture of the cervical spine will progress into kyphosis and continue if the load balance and lordosis is not restored. The content of this paper will address the physiological and biomechanical pathways leading to cervical spondylosis and the biomechanical principles related to the surgical correction and treatment of kyphotic progression. PMID:22400120

  2. The biomechanics of cervical spondylosis.

    PubMed

    Ferrara, Lisa A

    2012-01-01

    Aging is the major risk factor that contributes to the onset of cervical spondylosis. Several acute and chronic symptoms can occur that start with neck pain and may progress into cervical radiculopathy. Eventually, the degenerative cascade causes desiccation of the intervertebral disc resulting in height loss along the ventral margin of the cervical spine. This causes ventral angulation and eventual loss of lordosis, with compression of the neural and vascular structures. The altered posture of the cervical spine will progress into kyphosis and continue if the load balance and lordosis is not restored. The content of this paper will address the physiological and biomechanical pathways leading to cervical spondylosis and the biomechanical principles related to the surgical correction and treatment of kyphotic progression. PMID:22400120

  3. 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

  4. Radiotherapy of Cervical Cancer.

    PubMed

    Vordermark, Dirk

    2016-01-01

    Curative-intent radical radiotherapy of cervical cancer consists of external-beam radiotherapy, brachytherapy, and concomitant chemotherapy with cisplatin. For each element, new developments aim to improve tumor control rates or treatment tolerance. Intensity-modulated radiotherapy (IMRT) has been shown to reduce gastrointestinal toxicity and can be used to selectively increase the radiotherapy dose. Individualized, image-guided brachytherapy enables better adaptation of high-dose volumes to the tumor extension. Intensification of concomitant or sequential systemic therapy is under evaluation. PMID:27614991

  5. Electrodiagnosis of cervical radiculopathy.

    PubMed

    Hakimi, Kevin; Spanier, David

    2013-02-01

    Cervical radiculopathy is a common diagnosis with a peak onset in the fifth decade. The most commonly affected nerve root is C7, C6, and C8. The etiology is often compressive, but may arise from noncompressive sources. Patients commonly complain of pain, weakness, numbness, and/or tingling. Examination may reveal sensory or motor disturbance in a dermatomal/myotomal distribution. Neural compression and tension signs may be positive. Diagnostic tests include imaging and electrodiagnostic study. Electrodiagnostic study serves as an extension of the neurologic examination. Electrodiagnostic findings can be useful for patients with atypical symptoms, potential pain-mediated weakness, and nonfocal imaging findings.

  6. [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.

  7. Silver doped titanium oxide-PDMS hybrid coating inhibits Staphylococcus aureus and Staphylococcus epidermidis growth on PEEK.

    PubMed

    Tran, Nhiem; Kelley, Michael N; Tran, Phong A; Garcia, Dioscaris R; Jarrell, John D; Hayda, Roman A; Born, Christopher T

    2015-04-01

    Bacterial infection remains one of the most serious issues affecting the successful installation and retention of orthopedic implants. Many bacteria develop resistance to current antibiotics, which complicates or prevents traditional antibiotic-dependent eradication therapy. In this study, a hybrid coating of titanium dioxide and polydimethylsiloxane (PDMS) was synthesized to regulate the release of silver. The coatings were benefited from the antimicrobial activity of silver ion, the biocompatibility of titanium dioxide, and the flexibility of the polymer. Three studied silver doped coatings with different titanium dioxide-PDMS ratios effectively inhibited the attachment and growth of Staphylococcus aureus and Staphylococcus epidermidis in a dose-dependent manner. The coatings were successfully applied on the discs of polyether ether ketone (PEEK), a common spinal implant material and antibacterial property of these coatings was assessed via Kirby Bauer assay. More importantly, these selected coatings completely inhibited biofilm formation. The release study demonstrated that the release rate of silver from the coating depended on doping levels and also the ratios of titanium dioxide and PDMS. This result is crucial for designing coatings with desired silver release rate on PEEK materials for antimicrobial applications.

  8. Invasive Cervical Cancer and Antidepressants

    PubMed Central

    Chan, Hsiang-Lin; Hsieh, Yi-Hsuan; Lin, Chiao-Fan; Liang, Hsin-Yi; Huang, Kuo-You; Chiu, Wei-Che; Lee, Yena; McIntyre, Roger S.; Chen, Vincent Chin-Hung

    2015-01-01

    Abstract To our knowledge, no prior population-based study has been published wherein the primary aim was to evaluate whether an association between psychotropic drug prescription and cervical cancer exists. Herein we have conducted the first study that primarily aimed to determine the association between antidepressants use and risk of invasive cervical cancer in the general population. This is a population-based study utilizing Taiwan's National Health Insurance Research Database. We identified 26,262 cases with invasive cervical cancer and 129,490 controls. We adopted the conditional logistic regression model as the statistical method and adjusted for potential confounding factors. The prescription of selective serotonin reuptake inhibitors (SSRIs) (adjusted OR = 0.93, 95% CI = 0.84–1.04), tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), serotonin norepinephrine reuptake inhibitors (SNRIs), mirtazapine and bupropion, adjusting for cumulative dose, was not associated with an increased, or decreased, risk for invasive cervical cancer. An association between trazodone prescription and invasive cervical cancer was observed (adjusted OR = 1.22, 95% CI = 1.03–1.43). An association between the major classes of antidepressants and invasive cervical cancer was not observed herein. Our preliminary finding regarding a possible association between trazodone and cervical cancer requires replication. PMID:26496343

  9. Cervical Tissue Engineering Using Silk Scaffolds and Human Cervical Cells

    PubMed Central

    Sanchez, Cristina C.; Rice, William L.; Socrate, Simona; Kaplan, David L.

    2010-01-01

    Spontaneous preterm birth is a frequent complication of pregnancy and a common cause of morbidity in childhood. Obstetricians suspect abnormalities of the cervix are implicated in a significant number of preterm births. The cervix is composed of fibrous connective tissue and undergoes significant remodeling in preparation for birth. We hypothesized that a tissue engineering strategy could be used to develop three-dimensional cervical-like tissue constructs that would be suitable for investigating cervical remodeling. Cervical cells were isolated from two premenopausal women undergoing hysterectomy for a benign gynecological condition, and the cells were seeded on porous silk scaffolds in the presence or absence of dynamic culture and with 10% or 20% serum. Morphological, biochemical, and mechanical properties were measured during the 8-week culture period. Cervical cells proliferated in three-dimensions and synthesized an extracellular matrix with biochemical constituents and morphology similar to native tissue. Compared to static culture, dynamic culture was associated with significantly increased collagen deposition (p < 0.05), sulfated glycosaminoglycan synthesis (p < 0.05), and mechanical stiffness (p < 0.05). Serum concentration did not affect measured variables. Relevant human tissue-engineered cervical-like constructs constitute a novel model system for a range of fundamental and applied studies related to cervical remodeling. PMID:20121593

  10. Resection of cervical ependymoma.

    PubMed

    Lanzino, Giuseppe; Morales-Valero, Saul F; Krauss, William E; Campero, Mario; Marsh, W Richard

    2014-09-01

    Intramedullary ependymomas are surgically curable tumors. However, their surgical resection poses several challenges. In this intraoperative video we illustrate the main steps for the surgical resection of a cervical intramedullary ependymoma. These critical steps include: adequate exposure of the entire length of the tumor; use of the intraoperative ultrasound; identification of the posterior median sulcus and separation of the posterior columns; Identification of the plane between the spinal cord and the tumor; mobilization and debulking of the tumor and disconnection of the vascular supply (usually from small anterior spinal artery branches). Following these basic steps a complete resection can be safely achieved in many cases. The video can be found here: http://youtu.be/QMYXC_F4O4U. PMID:25175575

  11. 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 ...

  12. Get Tested for Cervical Cancer

    MedlinePlus

    ... help understanding your Pap test result . What about cost? Testing for cervical cancer is covered under the ... may be able to get tested at no cost to you. If you have private insurance, check ...

  13. [Diagnosis and therapy of cervical insufficiency].

    PubMed

    Matijević, Ratko; Grgić, Ozren; Klobucar, Ante

    2003-01-01

    Cervical insufficiency is one of the risk factors for late spontaneous miscarriage and preterm labor. As cervical insufficiency can reoccur in the every subsequent pregnancy, there is a need for precise diagnostic modality and therapeutic procedure in order to reduce perinatal mortality and morbidity. Traditionally, the diagnosis of cervical insufficiency was made based on the patient's history. In this cases the intervention in the form of the cervical cerclage, was not found to be useful, i.e. perinatal mortality and morbidity remained unchanged. It is a similar situation in cervical insufficiency suspected based on hysterosalpingography and clinical examination. Recently, ultrasound, or more precisely transvaginal cervical assessment--cervicometry, was introduced in order to assess the morphological changes indicative for cervical insufficiency. In this literature review, we analyzed ultrasound based markers of cervical insufficiency, with their specificity, sensitivity, positive and negative predictive value, as well as usefulness of cervical cerclage in such cases.

  14. How Are Cervical Cancers and Pre-Cancers Diagnosed?

    MedlinePlus

    ... How is cervical cancer staged? How is cervical cancer diagnosed? The first step in finding cervical cancer ... systems. Tests for women with symptoms of cervical cancer or abnormal Pap results Medical history and physical ...

  15. 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

  16. Cervical cord injury after massage.

    PubMed

    Lee, Tzu-Han; Chiu, Jan-Wei; Chan, Rai-Chi

    2011-10-01

    We present the case of a 47-yr-old gentleman with cervical cord injury after he received massage in the neck area. Magnetic resonance imaging of the cervical spine showed a herniation of the nucleus pulposus and compressive myelopathy. The patient required surgical intervention and rehabilitation. Despite 6 mos of rehabilitation, residual hand dysfunction and minor ambulation problems persisted. Although massage has many benefits, this case reminds us that there is potential danger in performing neck massage. PMID:21862908

  17. 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

  18. 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.

  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. 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. Cervical insufficiency: re-evaluating the prophylactic cervical cerclage.

    PubMed

    Abenhaim, Haim A; Tulandi, Togas

    2009-06-01

    Historically, placement of a cervical cerclage was based almost entirely on the obstetrical history. Over the past two decades however, we have recognised that history alone may not be the only indication for cerclage but rather, complementing the obstetrical history with ultrasonographic and biochemical findings may better identify those women who may benefit most from the placement of a cervical cerclage. Review of the literature appears to suggest that the best approach towards the management of a cervical insufficiency is to first categorise women as being either high risk of low risk-based on obstetrical history. Although women with an obstetrical history of at least three 2nd trimester losses are likely to benefit from a prophylactic cerclage than those without this history may better be managed with progesterone and serial cervical length measurements. This approach can in turn be used to identify those women with early cervical shortening that may require an emergency cerclage. Although randomised controlled trials are still lacking, recent studies suggests that this approach may be more effective especially when combined with markers of intra-amniotic inflammation. As for the prophylactic cerclage itself, with the abdominal cerclage being less invasive given the possibility of a laparoscopic placement, it may prove to be a more effective alternative to the conventionally placed McDonald cerclage. This however, remains to be evaluated more carefully.

  2. Nano-TiO2 reinforced PEEK/PEI blends as biomaterials for load-bearing implant applications.

    PubMed

    Díez-Pascual, Ana M; Díez-Vicente, Angel L

    2015-03-11

    Biocompatible ternary nanocomposites based on poly(ether ether ketone) (PEEK)/poly(ether imide) (PEI) blends reinforced with bioactive titanium dioxide (TiO2) nanoparticles were fabricated via ultrasonication followed by melt-blending. The developed biomaterials were characterized using FT-IR, SEM, XRD, DSC, TGA, and DMA. Further, their water-absorption, tensile, tribological, dielectric, and antibacterial properties were evaluated. PEI acts as a coupling agent, since it can interact both with PEEK via π-π stacking and polar interactions as well as with the nanoparticles through hydrogen bonding, as corroborated by the FT-IR spectra, which resulted in a homogeneous titania dispersion within the biopolymer blend without applying any particle surface treatment or polymer functionalization. A change from promotion to retardation in the crystallization rate of the matrix was found with increasing TiO2 concentration, while its crystalline structure remained unaltered. The nanoparticles stiffened, strengthened, and toughened the matrix simultaneously, and the optimal properties were achieved at 4.0 wt % TiO2. More interesting, the tensile properties were retained after steam sterilization in an autoclave or exposure to a simulated body fluid (SBF). The nanocomposites also displayed reduced water absorption though higher thermal stability, storage modulus, glass transition temperature, dielectric constant, and dielectric loss compared to the control blend. Further, remarkable enhancements in the tribological properties under both SBF and dry environments were attained. The nanoparticles conferred antibacterial action versus Gram-positive and Gram-negative bacteria in the presence and the absence of UV light, and the highest inhibition was attained at 4.0 wt % nanoparticle concentration. These nanocomposites are expected to be used in long-term load-bearing implant applications. PMID:25706225

  3. [Therapy of cervical rheumatoid arthritis].

    PubMed

    Kothe, R; Wiesner, L; Rüther, W

    2004-08-01

    The rheumatoid involvement of the cervical spine can be divided into three phases. In the early stage of the disease there is an isolated atlantoaxial subluxation (AAS), followed by vertical instability and subaxial instability. If patients show clear symptoms of cervical myelopathy, which can occur during any stage of the disease, the progression cannot be stopped by conservative treatment, which is of great importance at the beginning of the cervical manifestation. Patient education, physiotherapy and immobilization with a stiff collar can significantly reduce pain. Early and effective DMARD therapy can have a positive effect on the natural history of the disease. In case of progressive instability, cervical myelopathy or severe pain operative treatment is indicated. If there is an isolated AAS, fusion can be restricted to the C1/C2 segment. The Magerl transarticular screw fixation is the preferred technique for stabilization. If there is evidence for vertical instability or severe destruction of the C0/C1 joints, occipital cervical fusion has to be performed. Durin the preoperative planning it is necessary to look for signs of subaxial instability. If this is the case, fusion should include the entire cervical spine. Transoral decompression may be necessary when there is persistent anterior compression of the myelon, typically seen in fixed AAS. Non-ambulatory myelopathic patients are more likely to develop severe surgical complications. Therefore, it is important to avoid the development of severe cervical instability by early surgical intervention. The right timing for surgery is still a matter of controversy. Future prospective randomized trials should address this topic to improve the treatment concept for the rheumatoid patient.

  4. 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.

  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. American Society for Colposcopy and Cervical Pathology

    MedlinePlus

    ... Prevention of Cervical Cancer ASCCP has endorsed American Society of Clinical Oncology's Guidelines for Secondary Prevention of ... 7227 Toll-Free (240) 575-9880 Fax © American Society for Colposcopy and Cervical Pathology * Required * First Name: * ...

  7. 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.

  8. 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.

  9. [Cervical incompetence after previous cervical dilatation and curettage (author's transl)].

    PubMed

    Grünberger, W; Riss, P

    1979-07-15

    Out of a total of 3502 deliveries over a period of two years 254 patients (7.25%) had a surgical closure of the cervix according to Shirodkar because of cervical incompetence. All 3502 records were reviewed with regard to previous obstetrical and gynecological history. In the group with Shirodkar operation the percentage of women with a history of spontaneous or induced abortions was almost twice as high as in the comparison group. The reason for the development of cervical incompetence could be a trauma to the endocervix due to mechanical dilatation since diagnostic or therapeutic dilatation and curettage was found five times more often in women with Shirodkar operation than in patients without cervical incompetence. The results show that dilatation and curettage for any indication should be performed as carefully as possible, especially in younger women of childbearing age. Chemical dilatation of the endocervix--for example with prostaglandins--seems to be preferable to mechanical dilatation.

  10. 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

  11. 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

  12. Cervical incompetence: preliminary evaluation with MR imaging.

    PubMed

    Hricak, H; Chang, Y C; Cann, C E; Parer, J T

    1990-03-01

    The ability of magnetic resonance (MR) imaging to demonstrate cervical incompetence in nonpregnant women was investigated in a prospective study of 41 volunteers referred in random order. These included 20 patients with normal cervices, 11 with cervical incompetence of traumatic or congenital origin, and 10 with clinically small cervices due to in utero diethylstilbestrol (DES) exposure. On MR images of the normal patients, cervical length was 33.0 mm +/- 1.0 (mean +/- standard error of the mean) and the width of the internal cervical os was 3.3 mm +/- 0.1. In patients with cervical incompetence, the cervical length did not significantly differ from those in the normal group. However, the internal cervical os was significantly wider (4.5 mm +/- 0.3, P less than .001), and localized irregularity of the endocervical canal was demonstrated in two patients. The MR appearance of the cervical stroma varied from normal, uniformly low signal intensity (n = 4) to uniformly (n = 3) or partially (n = 4) medium-to-high signal intensity on T2-weighted images. In the patients with in utero DES exposure, the mean length of the cervical canal (22.9 mm +/- 1.7) was significantly shorter than that of the normal group. The width of the internal cervical os and the MR signal intensity of the cervical stroma were normal. In summary, MR findings of a cervical length shorter than 3.1 mm (95% confidence limit), an internal cervical os wider than 4.2 mm (95% confidence limit), or abnormal signal intensity in the cervical stroma are highly suggestive of incompetent cervix and should assist in planning further therapeutic decisions. PMID:2305065

  13. 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.

  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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  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...

  2. Invasive cervical cancer in pregnancy.

    PubMed

    La Russa, M; Jeyarajah, A R

    2016-05-01

    Detection of invasive cervical cancer during pregnancy is rare, with reported incidence rates ranging from 0.05% to 0.1%. However, cervical cancer is one of the most common malignancies diagnosed during pregnancy. The management of invasive cervical cancer in pregnancy is extremely challenging and requires a multidisciplinary team approach to optimise the treatment for the patient by simultaneously providing the best chance of survival for the foetus. The approach is based mainly on the following factors: gestational age at the time of the diagnosis, stage, histological subtype, desire regarding fertility and quality of life. The gold standard treatment for this condition in pregnancy is not yet established. This is due to the absence of prospective studies and clinical trials. Therefore, its management presents a dilemma that requires individualisation of care. The various factors that need to be considered for obtaining a good outcome for both mother and child are described in this study. PMID:26586539

  3. Cervical cancer: a preventable death.

    PubMed

    Nour, Nawal M

    2009-01-01

    Cervical cancer kills 260,000 women annually, and nearly 85% of these deaths occur in developing nations, where it is the leading cause of cancer deaths in women. Disparities of health and poverty play a large role in this high mortality rate. Whereas routine Papanicolaou and human papillomavirus (HPV) testing has dramatically reduced cervical cancer deaths in Western nations, without proper infrastructure, facilities, and medical training, the rates of cervical cancer in developing nations will remain high. Studies on HPV DNA testing and the low-technology method of "screen and treat" are promising. In addition, reducing the cost and increasing the availability of HPV vaccines in developing nations brings hope and promise to the next generation of women. PMID:20111660

  4. Spontaneous cervical and mediastinal emphysema.

    PubMed

    Parker, G S; Mosborg, D A; Foley, R W; Stiernberg, C M

    1990-09-01

    Subcutaneous cervical emphysema often appears as a result of surgery or trauma. However, when it occurs spontaneously, the patient may present with clinically impressive and dramatic features. The etiology is related to the rupture of terminal alveoli and dissection of air along the pulmonary vasculature. Exercise may contribute to the process by increases in intrathoracic pressure. Six cases of spontaneous cervical emphysema, all related to SCUBA diving training at a Naval facility, were recently seen at our institution. Proper management entails having a high index of suspicion for diagnosis, and then being able to identify potentially life-threatening complications.

  5. Stress-induced cervical lesions.

    PubMed

    Braem, M; Lambrechts, P; Vanherle, G

    1992-05-01

    The increasing occurrence of dental lesions at the cervical surfaces requires more knowledge of the causes of the process. Acidic and abrasive mechanisms have clearly been documented as causes but the stress theory by Lee and Eakle is still controversial. This report describes several incidences of possible stress-induced lesions according to the characteristics described by Lee and Eakle. The occurrences of subgingival lesions lend credence to the stress-induction theory by exclusion of other superimposing etiologic factors. With the current concepts, a perceptive approach to the treatment of cervical lesions can be executed. PMID:1527763

  6. 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

  7. Cervical spine pain in the competitive athlete.

    PubMed

    Krabak, Brian J; Kanarek, Samantha L

    2011-08-01

    Cervical pain is a common complaint in both the well-conditioned athlete and the weekend warrior. Some injuries are mild in nature, responding to conservative treatment, including rest, medication, physical therapy, and time. However, more serious injuries, especially those involving the cervical spine, can have devastating consequences. Having a comprehensive understanding of the evaluation and management of cervical pain and cervical spine emergencies is crucial for physicians providing coverage for organized athletic events or for those who serve as team physicians. This article reviews the common causes of cervical spine pain in the competitive athlete.

  8. 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.

  9. 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.

  10. Synthesis and properties of side-chain-type ion exchange membrane PEEK-g-StSO 3Na for bipolar membranes

    NASA Astrophysics Data System (ADS)

    Huang, Xuehong; Huang, Dengbin; Ou, Xiaojuan; Ding, Fuchuan; Chen, Zhen

    2012-01-01

    Side-chain-type ion exchange membranes (PEEK-g-StSO3Na) were prepared by grafting poly (ether ether ketone) (PEEK) containing propenyl groups with sodium sulfonic styrene (StSO3Na) and KH570. PEEK was synthesized by the aromatic nucleophilic polycondensation reaction of 4,4‧-difluorobenzophenone, bisphenol A and diallylbisphenol A. The synthesized copolymers with the -SO3Na group on the side chain of polymers possessed high molecular weights. The cross-linking reaction was carried out through a sol-gel reaction of the trimethoxysilane group. The copolymer membranes exhibited excellent mechanical properties due to their aromatic structure extending through the backbone and flexible StSO3Na aliphatic chains. The ion exchange capacities (IECs) of the membranes ranged from 2.27 to 2.50 mmol g-1 and the water content ranged from 107.2 to 126.1%, with both parameters increasing with StSO3Na grafting degree. The H+ permeability of copolymer membranes increased with increasing IEC, reaching value above 0.3056 mol/L at 2 h, which is higher than that of Nafion® 117 at the same measurement condition. They displayed reasonably high H+ permeability due to the higher acidity of benzoyl sulfonic acid group, the larger interchain spacing, which is available for water occupation, and the lower AC impedance of the bipolar membrane.

  11. Development of poly(ether ether ketone)(PEEK) derived from bisphenol-S for proton exchange membrane (PEM) in direct methanol fuel cells (DMFC)

    NASA Astrophysics Data System (ADS)

    Changkhamchom, Sairung; Sirivat, Anuvat

    2008-03-01

    The currently used Proton Exchange Membrane (PEM) in Direct Methanol Fuel Cell (DMFC) is Nafion?, an excellent proton conductivity in fully hydrated membrane. However, it has major drawbacks such as very high cost, and lost of conductivity at elevated temperature and low humidity. In our work, the novel PEM was based on sulfonated poly(ether ether ketone) (S-PEEK) which was synthesized by the nucleophilic aromatic substitution polycondensation of bisphonol-S, 4,4'-dichlorobenzophenone (DCBP), and sodium 5,5'-carbonylbis(2-chlorobenzenesulfonate) (SDCBP). Bisphenol-S is expected to improve thermal stability due to its high melting point (245oC). S-PEEK was characterized by FTIR, 1H-NMR, TGA, DSC, and titration to determine the degree of sulfonation (D.S.). Composite membranes were prepared by using S-PEEK as polymer matrix and heteropolyacid (HPA) as an inorganic filler. The phosphotungstic acid (PTA) was used due to its highly proton conductivity at high temperature and low water uptake. The membranes were characterized by SEM, TGA, DSC, DMTA, and by the measurements of the water uptake (%), the swelling ratio (%), the ion exchange capacities (IEC), the methanol diffusion coefficient, and the proton conductivity.

  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. Cervical epidural arteriovenous fistula with radiculopathy mimicking cervical spondylosis.

    PubMed

    Kawabori, Masahito; Hida, Kazutoshi; Yano, Shunsuke; Asano, Takeshi; Iwasaki, Yoshinobu

    2009-03-01

    A 65-year-old woman presented with a rare case of cervical epidural arteriovenous fistula (AVF) manifesting as radiculopathy of the right upper extremity that mimicked cervical spondylosis. She had a 2-month history of gradually progressive right-hand motor weakness and sensory disturbance. The initial diagnosis was cervical disk herniation. However, computed tomography with contrast medium showed abnormal enhancement at the right C5-6 and C6-7 intervertebral foramina. Magnetic resonance (MR) imaging with gadolinium disclosed an enhanced abnormal epidural mass at the dorsal surface of the dural tube between the C5 and C6 vertebrae. T(2)-weighted MR imaging showed a slight flow void on the dorsal and ventral surfaces of the spinal cord between C3 and T4. Digital subtraction angiography disclosed cervical epidural and dural AVFs fed by the C5 and C6 radicular arteries. The diagnosis was concomitant epidural and dural AVFs. The dilated internal vertebral venous plexus attributable to epidural AVF was considered to be responsible for the radiculopathy. Transarterial embolization using n-butylcyanoacrylate achieved complete occlusion of the lesions. Her symptoms improved immediately and MR imaging and angiography performed 10 days postembolization showed reduction of both the epidural and dural AVFs.

  14. Percutaneous cervical nucleoplasty in the treatment of cervical disc herniation.

    PubMed

    Li, Jian; Yan, Deng-lu; Zhang, Zai-Heng

    2008-12-01

    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) > or =11 degrees or horizontal displacement (HD) > or =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

  15. [Cervical pessary and prevention of preterm birth].

    PubMed

    Sentilhes, L; Descamps, P; Legendre, G

    2014-01-01

    Cervical pessary is a promising tool to prevent preterm birth in high risk pregnant women with shortened midtrimester ultrasonographic cervical length. It is well tolerated by women. PECEP and ProTWIN trials have opened new fields of clinical research. Their results suggest that cervical pessary may prevent preterm birth in women with (i) singleton and cervical length ≤25 mm at 18-22weeks, and with (ii) twins and cervical length ≤37mm at 16-22weeks. These results must be confirmed by other randomized controlled trial before a generalization of cervical pessary in these situations. The role of cervical pessary in the existing strategies to prevent birth (progesterone, cerclage or combinations thereof) has to be determined.

  16. Cervical Cancer Risk Prediction Models

    Cancer.gov

    Developing statistical models that estimate the probability of developing cervical cancer over a defined period of time will help clinicians identify individuals at higher risk of specific cancers, allowing for earlier or more frequent screening and counseling of behavioral changes to decrease risk.

  17. Nonoperative Management of Cervical Radiculopathy.

    PubMed

    Childress, Marc A; Becker, Blair A

    2016-05-01

    Cervical radiculopathy describes pain in one or both of the upper extremities, often in the setting of neck pain, secondary to compression or irritation of nerve roots in the cervical spine. It can be accompanied by motor, sensory, or reflex deficits and is most prevalent in persons 50 to 54 years of age. Cervical radiculopathy most often stems from degenerative disease in the cervical spine. The most common examination findings are painful neck movements and muscle spasm. Diminished deep tendon reflexes, particularly of the triceps, are the most common neurologic finding. The Spurling test, shoulder abduction test, and upper limb tension test can be used to confirm the diagnosis. Imaging is not required unless there is a history of trauma, persistent symptoms, or red flags for malignancy, myelopathy, or abscess. Electrodiagnostic testing is not needed if the diagnosis is clear, but has clinical utility when peripheral neuropathy of the upper extremity is a likely alternate diagnosis. Patients should be reassured that most cases will resolve regardless of the type of treatment. Nonoperative treatment includes physical therapy involving strengthening, stretching, and potentially traction, as well as nonsteroidal anti-inflammatory drugs, muscle relaxants, and massage. Epidural steroid injections may be helpful but have higher risks of serious complications. In patients with red flag symptoms or persistent symptoms after four to six weeks of treatment, magnetic resonance imaging can identify pathology amenable to epidural steroid injections or surgery. PMID:27175952

  18. Drugs Approved for Cervical Cancer

    Cancer.gov

    This page lists cancer drugs approved by the Food and Drug Administration (FDA) for cervical cancer. The list includes generic names, brand names, and common drug combinations, which are shown in capital letters. The drug names link to NCI's Cancer Drug Information summaries.

  19. Nanomechanical clues from morphologically normal cervical squamous cells could improve cervical cancer screening

    NASA Astrophysics Data System (ADS)

    Geng, Li; Feng, Jiantao; Sun, Quanmei; Liu, Jing; Hua, Wenda; Li, Jing; Ao, Zhuo; You, Ke; Guo, Yanli; Liao, Fulong; Zhang, Youyi; Guo, Hongyan; Han, Jinsong; Xiong, Guangwu; Zhang, Lufang; Han, Dong

    2015-09-01

    Applying an atomic force microscope, we performed a nanomechanical analysis of morphologically normal cervical squamous cells (MNSCs) which are commonly used in cervical screening. Results showed that nanomechanical parameters of MNSCs correlate well with cervical malignancy, and may have potential in cancer screening to provide early diagnosis.Applying an atomic force microscope, we performed a nanomechanical analysis of morphologically normal cervical squamous cells (MNSCs) which are commonly used in cervical screening. Results showed that nanomechanical parameters of MNSCs correlate well with cervical malignancy, and may have potential in cancer screening to provide early diagnosis. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr03662c

  20. Preparation and characterization of sulfonated PEEK-WC membranes for fuel cell applications. A comparison between polymeric and composite membranes

    NASA Astrophysics Data System (ADS)

    Regina, A.; Fontananova, E.; Drioli, E.; Casciola, M.; Sganappa, M.; Trotta, F.

    Sulfonated poly(etheretherketone) with a cardo group (SPEEK-WC) exhibiting a wide range of degree of sulfonation (DS) was used to prepare polymeric membranes and composite membranes obtained by incorporation of an amorphous zirconium phosphate sulfophenylenphosphonate (Zr(HPO 4)(O 3PC 6H 4SO 3H), hereafter Zr(SPP)) in a SPEEK-WC matrix. The nominal composition of the composite membranes was fixed at 20 wt% of Zr(SPP). Both types of membrane were characterized for their proton conductivity, methanol permeability, water and/or methanol uptake, morphology by SEM and mechanical properties. For comparison, a commercial Nafion 117 membrane was characterized under the same operative conditions. The composite membranes exhibited a reduced water uptake in comparison with the polymeric membranes especially at high DS values and temperature higher than 50 °C. As a result, the water uptake into composite membranes remained about constant in the range 20-70 °C. The methanol permeability (P) of both polymeric and composite membranes was always lower than that of a commercial Nafion 117 membrane. At 22 °C and 100% relative humidity (RH), the proton conductivities (σ) of the polymeric membranes increased from 6 × 10 -4 to 1 × 10 -2 S cm -1 with the increase of DS from 0.1 to 1.04. The higher conductivity value was comparable with that of Nafion 117 membrane (3 × 10 -2 S cm -1) measured under the same operative conditions. The conductivities of the composite membranes are close to that of the corresponding polymeric membranes, but they are affected to a lesser extent by the polymer DS. The maximum value of the σ/ P ratio (about 7 × 10 4 at 25 °C) was found for the composite membrane with DS = 0.2 and was 2.5 times higher than the corresponding value of the Nafion membrane.

  1. Cervical cancer: screening, diagnosis and staging.

    PubMed

    Tsikouras, Panagiotis; Zervoudis, Stefanos; Manav, Bachar; Tomara, Eirini; Iatrakis, George; Romanidis, Constantinos; Bothou, Anastasia; Galazios, George

    2016-01-01

    Purpose: Despite the widespread screening programs, cervical cancer remains the third most common cancer in developing countries. Based on the implementation of cervical screening programs with the referred adoption of improved screening methods in cervical cytology with the knowledge of the important role of the human papilloma virus (HPV) it's incidence is decreased in the developed world. Even if cervical HPV infection is incredibly common, cervical cancer is relatively rare. Depending on the rarity of invasive disease and the improvement of detection of pre-cancerous lesions due to the participation in screening programs, the goal of screening is to detect the cervical lesions early in order to be treated before cancer is developed. In populations with many preventive screening programs, a decrease in cervical cancer mortality of 50-75% is mentioned over the past 50 years. The preventive examination of vagina and cervix smear, Pap test, and the HPV DNA test are remarkable diagnostic tools according to the American Cancer Association guidelines, in the investigation of asymptomatic women and in the follow up of women after the treatment of pre-invasive cervical cancer. The treatment of cervical cancer is based on the FIGO 2009 cervical cancer staging.

  2. Cervical cancer: screening, diagnosis and staging.

    PubMed

    Tsikouras, Panagiotis; Zervoudis, Stefanos; Manav, Bachar; Tomara, Eirini; Iatrakis, George; Romanidis, Constantinos; Bothou, Anastasia; Galazios, George

    2016-01-01

    Purpose: Despite the widespread screening programs, cervical cancer remains the third most common cancer in developing countries. Based on the implementation of cervical screening programs with the referred adoption of improved screening methods in cervical cytology with the knowledge of the important role of the human papilloma virus (HPV) it's incidence is decreased in the developed world. Even if cervical HPV infection is incredibly common, cervical cancer is relatively rare. Depending on the rarity of invasive disease and the improvement of detection of pre-cancerous lesions due to the participation in screening programs, the goal of screening is to detect the cervical lesions early in order to be treated before cancer is developed. In populations with many preventive screening programs, a decrease in cervical cancer mortality of 50-75% is mentioned over the past 50 years. The preventive examination of vagina and cervix smear, Pap test, and the HPV DNA test are remarkable diagnostic tools according to the American Cancer Association guidelines, in the investigation of asymptomatic women and in the follow up of women after the treatment of pre-invasive cervical cancer. The treatment of cervical cancer is based on the FIGO 2009 cervical cancer staging. PMID:27273940

  3. Hybrid Strategy of Two-Level Cervical Artificial Disc and Intervertebral Cage

    PubMed Central

    Chung, Tzu-Tsao; Hueng, Dueng-Yuan; Lin, Shang-Chih

    2015-01-01

    Abstract This numerical study aimed to evaluate tissue and implant responses to the hybrid surgery (HS) of cervical artificial disc replacement (C-ADR) and anterior cervical discectomy and fusion (ACDF). Four hybrid strategies of two-level C-ADR and ACDF were compared in terms of adjacent segment degeneration (ASD) and implant failure. The rotary C-ADR and semirigid ACDF have been extensively used in the multilevel treatment of cervical instability and degeneration, but the constrained mobility at the ACDF segments can induce postoperative ASD problems. Hybrid surgery of C-ADR and ACDF has been an alternative to provide the optimal tradeoff between surgical cost and ASD problems. The biomechanical effects of hybrid strategies warrant thorough investigation for the two-level instrumentation. Based on computed tomography imaging, a nonlinear C2–C7 model was developed and validated by cadaveric and numerical data. Four strategies of inserting the C-ADR and ACDF into the C4–C6 segments were systematically arranged as PP (2 peek cages), AA (2 artificial discs), PA, and AP. The biomechanical behavior of these 4 strategies was evaluated in terms of motion and stresses of discs, facet forces, stresses of C-ADR and ACDF, and C-ADR motion. The constrained mobility of the ACDF segment worsened the kinematic and mechanical demands of the adjacent segments and artificial discs. The C-ADR articulation provided higher mobility than the replaced disc of the intact construct, making it an effective buffer to accommodate the compensated mobility and load from the ACDF segment. Consequently, the ASD progression of the AA construct was most restricted, followed by the PA, AP, and PP construct. The PA strategy is a tradeoff to preserve mobility and reduce cost. The C-ADR of the PA construct preserves the mobility of the C5/C6 segment and shares the transferred motion and loads of the fused C4/C5 segment. The PA construct shows optimal biomechanical results for minimizing ASD and

  4. Epidemiology of uterine cervical cancer.

    PubMed

    Brinton, L A; Fraumeni, J F

    1986-01-01

    The epidemiology of cervical cancer presents a number of unique challenges, mainly with respect to disentangling correlated factors and to elucidating biological mechanisms. The available evidence suggests a complex multifactorial etiology, although the relative contributions of risk factors and their interactions remain obscure. Infectious agents are strongly suspected, but as yet not conclusively identified. It is also unclear whether there are subgroups of women or periods of life that are most susceptible to the action of infectious agents, and the contribution of the "male factor" needs to be defined. Several epidemiologic leads can be pursued through biochemical and molecular techniques. Most promising is the recent evidence linking certain HPV types to cervical abnormalities, including cancer, and newly developed probes can be incorporated into epidemiologic studies to evaluate an array of risk factors. Endocrine and metabolic assays may be helpful in clarifying the role of exogenous and possibly endogenous hormones. The effects of cigarette smoking may be further evaluated by studying constituents of tobacco smoke and their metabolites in cervical mucus. Finally, the relationship of diet to cervical cancer should be assessed by examining the levels of micronutrients, trace minerals, and other nutritional indices in body tissues and fluids, as well as through interview data. An understanding of cervical cancer etiology will require a better identification of risk factors for precursor lesions as well as factors that enhance their progression to invasive cancer. Through studies that focus on disease stage and time-related events, it should be possible to clarify the multi-stage processes involved in cervical carcinogenesis, and those factors that may inhibit as well as promote transition rates. The protective effects of screening programs deserve further attention, and research into dietary factors may lead in time to nutritional intervention. Investigation

  5. [Injury of upper cervical spine].

    PubMed

    Ryba, Luděk; Cienciala, Jan; Chaloupka, Richard; Repko, Martin; Vyskočil, Robert

    2016-01-01

    Injuries of the upper cervical spine represent 1/3 of all cervical spine injuries and approximately 40 % result by the death. Every level of the cervical spine can be injured - fractures of condyles of the occipital bone (CO), atlantooccipital dislocation (AOD), fractures of the Atlas (C1), atlantoaxial dislocation (AAD) and fractures of the axis (C2). Most of cases in younger patients are caused by high-energy trauma, while by elderly people, because of the osteoporosis, is needed much less energy and even simple falls can cause the injury of the cervical spine. That´s why the etiology of injuries can be different. In younger patients are caused mainly by car accidents, motorcycle and bicycle accidents and pedestrian crashes by car and in elderly populations are the main reason falls. The mechanism of the injury is axial force, hyperflexion, hyperextension, latero-flexion, rotation and combination of all. The basic diagnostic examination is X ray in AP, lateral and transoral projection. But in the most of cases is CT examination necessary and in the suspicion of the ligamentous injury and neurological deterioration must be MRI examination added. Every injury of the upper cervical spine has its own classification. Clinical symptoms can vary from the neck pain, restricted range of motion, antalgic position of the head, injury of the cranial nerves and different neurologic symptoms from the irritation of nerves to quadriplegia. A large percentage of deaths is at the time of the injury. Therapy is divided to conservative treatment, which is indicated in bone injuries with minimal dislocation. In more severe cases, with the dislocation and ligamentous injury, when is high chance of the instability, is indicated the surgical treatment. We can use anterior or posterior approach, make the osteosynthesis, stabilisation and fusion of the spine. Complex fractures and combination of different types of injuries are often present in this part of the spine. Correct and early

  6. 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.

  7. The influence of a compatibilizer on the thermal and dynamic mechanical properties of PEEK/carbon nanotube composites

    NASA Astrophysics Data System (ADS)

    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.

    2009-08-01

    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. Adhesion study of thermoplastic polyimides with Ti-6Al-4V alloy and PEEK-graphite composites

    SciTech Connect

    Yoon Taeho.

    1991-01-01

    High glass transition (e.g. 360C) melt processable thermoplastic polyimide homopolymers and poly(imide-siloxane) segmented copolymers were prepared from a number of diamines and dianhydrides via solution imidization, polydimethylsilxane segment incorporation and molecular weight control with non-reactive phthalimide end-groups. The adhesive bond performance of these polyimides was investigated as a function of molecular weight, siloxane incorporation, residual solvent, test temperature, and polyimide structure via single-lap shear samples prepared from treated Ti-6Al-4V alloy adherends and compression-molded film adhesives of scrim-cloth adhesives. The adhesive bond strengths increased greatly with siloxane-segment incorporation at 10, 20 and 30 wt% and decreased slightly with total polymer molecular weight. As the test temperature was increased, adhesive bond strength increased, decreased or showed a maximum at some temperatures depending on the polyimide structure and siloxane content. The poly(imide-30% siloxane) segmented copolymer and a miscible poly(ether-imide) also demonstrated excellent adhesive bond strength with poly(arylene ether ketone) PEEK{reg sign}-graphite composites.

  9. Cervical spondylosis and hypertension: a clinical study of 2 cases.

    PubMed

    Peng, Baogan; Pang, Xiaodong; Li, Duanming; Yang, Hong

    2015-03-01

    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

  10. What's New in Cervical Cancer Research and Treatment?

    MedlinePlus

    ... resources for cervical cancer What`s new in cervical cancer research and treatment? New ways to prevent and treat ... Your Doctor After Treatment What`s New in Cervical Cancer Research? Other Resources and References Cancer Information Cancer Basics ...

  11. Molecular imaging in cervical cancer.

    PubMed

    Khan, Sairah R; Rockall, Andrea G; Barwick, Tara D

    2016-06-01

    Despite the development of screening and of a vaccine, cervix cancer is a major cause of cancer death in young women worldwide. A third of women treated for the disease will recur, almost inevitably leading to death. Functional imaging has the potential to stratify patients at higher risk of poor response or relapse by improved delineation of disease extent and tumor characteristics. A number of molecular imaging biomarkers have been shown to predict outcome at baseline and/or early during therapy in cervical cancer. In future this could help tailor the treatment plan which could include selection of patients for close follow up, adjuvant therapy or trial entry for novel agents or adaptive clinical trials. The use of molecular imaging techniques, FDG PET/CT and functional MRI, in staging and response assessment of cervical cancer is reviewed. PMID:26859085

  12. [Hpv cofactors in cervical carcinogenesis].

    PubMed

    Pinto, Alvaro P; Tulio, Siumara; Cruz, Olívia Russo

    2002-01-01

    Human papillomavirus (HPV) plays a central rule in uterine cervix carcinogenesis. Other factors direct or indirectly influence the installation of this mechanism in cervical squamous epithelium. Investigations regarding mechanisms of interaction of these factors with viral elements are found in the literature of the last 20 years. The present review article discusses possible co-factors of HPV in the genesis of the squamous carcinoma of uterine cervix, taking into account only the factors whose association with the virus or cervical cancer has been documented by experimental studies, and not based just on clinical or epidemiological data. Among the approached parameters are immunological factors (local and humoral immune response), the association with Acquired Immune Deficiency Syndrome, genetic factors as protein p53 polymorphism, tabagism and the use of oral contraceptives. All these factors interact in variable intensity with oncoproteins and other HPV elements, increasing and facilitating the virus action in host cells, leading to the development of immortalization and carcinogenesis. PMID:12185639

  13. Schwannomatosis of Cervical Vagus Nerve

    PubMed Central

    Sasi, M. P.

    2016-01-01

    Cervical vagal schwannoma is a rare entity among lesions presenting as a neck mass. They are usually slow-growing benign lesions closely associated with the vagus nerve. They are usually solitary and asymptomatic. Multiple schwannomas occurring in patients without neurofibromatosis (NF) are rare and have recently been referred to as schwannomatosis. Here, we present a case of a neck mass that had imaging features suggestive of vagal schwannoma and was operated upon. Intraoperatively, it was discovered to be a case of multiple vagal cervical schwannoma, all directly related to the right vagus nerve, and could be resected from the nerve in toto preserving the function of the vagus nerve. Final HPR confirmed our pre-op suspicion of vagal schwannomatosis.

  14. [Inequalities in cervical screening practices].

    PubMed

    Döbrőssy, Lajos; Kovács, Attila; Budai, András

    2015-06-14

    Theoretically, the cytology-based cervical screening is capable of early detection of precancerous epithelial lesions of cervix uteri and its cancer, and of early referral to treatment. In this way, screening can inmprove the quality of life of the patients and reduce mortality from the target disease. Unfortunately, this often remains unexploited, because there might be inequalities on both "supply" and "demand" side of screening. In addition to the geopolitical situation of a country, inequalities might result from differences in the health care systems, and heavy access to the screening services. On the other hand, the socioeconomic status, the health-conciousness of the target population, and their knowledge and information of the benefits and potential harms of screening examination might have a bearing on the acceptance or refusal of the offered screening. Efforts need to be made to increase the uptake of cervical screening programmes.

  15. Cervical teratoma in a dog.

    PubMed

    Lambrechts, N E; Pearson, J

    2001-03-01

    A young adult boxer dog was examined for a painless swelling in the left cranial cervical area that was refractory to antibiotic therapy. Ultrasound examination revealed a hypoechoic mass abutting the rostrolateral aspect of the left mandibular salivary gland. The cystic mass was excised and was found to extend through the capsule of the salivary gland and appeared to be confluent with the glandular tissue at this point. Histopathological examination of the excised tissue demonstrated tissue from all 3 germinal layers. There was no indication of malignancy and the mass was diagnosed as a benign cervical teratoma. Hypotheses regarding the origin of teratomas in general are discussed and the origin of the teratoma in this case is suggested.

  16. Anterior cervical discectomy and fusion for noncontiguous cervical spondylotic myelopathy

    PubMed Central

    Qizhi, Sun; Peijia, Li; Lei, Sun; Junsheng, Chen; Jianmin, Li

    2016-01-01

    Background: Noncontiguous cervical spondylotic myelopathy (CSM) is a special degenerative disease because of the intermediate normal level or levels between supra and infraabnormal levels. Some controversy exists over the optimal procedure for two noncontiguous levels of CSM. The study was to evaluate the outcomes of the anterior cervical discectomy and fusion (ACDF) with zero-profile devices for two noncontiguous levels of CSM. Materials and Methods: 17 consecutive patients with two noncontiguous levels of CSM operated between December 2009 and August 2012 were included in the study. There were 12 men and 5 women with a mean age of 60.7 years (range 45–75 years). Involved disc levels were C3/4 and C5/6 in 11 patients and C4/5 and C6/7 in six patients. Preoperative plain radiographs, computed tomography (CT) with 3-D reconstruction and magnetic resonance imaging (MRI) of the cervical spine were taken in all patients. All radiographs were independently evaluated by 2 spine surgeons and 1 radiologist. The outcomes were assessed by the average operative time, blood loss, Japanese Orthopedic Association (JOA) score, improvement rate, neck dysfunction index (NDI), swallowing quality of life (SWAL-QOL) score, the cervical lordosis and complications. Results: The mean followup was 48.59 months (range 24-56 months). The average operative time and blood loss was 105.29 min and 136.47 ml, respectively. The preoperative JOA score was 8.35, which significantly increased to 13.7 at the final followup (P < 0.01). The NDI score was significantly decreased from preoperative 13.06 to postoperative 3.35 (P < 0.01). The operation also provided a significant increase in the cervical lordosis (P < 0.01) from preoperative 10.17° to postoperative 17.06°. The fusion rate was 94.1% at 6 months postoperatively, and 100% at 12 months after surgery. The mean SWAL-QOL score decreased from preoperative 68.06 to immediate postoperatively 65.65 and then increased to 67.65 at final followup

  17. Cyclic AMP in cervical mucus.

    PubMed

    Póvoa, H; Figueira, D R; Campos da Paz, A; Spichler, E R; Lopes, E R

    1981-01-01

    Cyclic adenosine monophosphate normally stimulates motility of spermatozoa. Its concentration in cervical mucus was studied by an isotopic competitive method in 15 normal women aged between 20 and 50 years. Values were very high, particularly in the periovulatory period, with a mean (+/-SD) value of 167.90 +/- 154.96 nmol/l. These are very high when compared with values in other biological fluids (blood serum and urine).

  18. Human papilloma virus and cervical preinvasive disease

    PubMed Central

    Bari, M; Iancu, G; Popa, F

    2009-01-01

    Cervical cancer lesions represent a major threat to the health of the women worldwide. Human Papillomavirus (HPV) is responsible for 99.7% of cervical cancer cases, the infectious etiology giving the possibility of preventing cervical cancer by vaccination. The most aggressive HPV types are 16 and 18, which cause about 70% of cases of invasive cancer. The vaccination is recommended to the girls aged 11–12. The diagnosis and the treatment of cervical preinvasive disease allow the doctor to prevent the development of the invasive disease. PMID:20108750

  19. Laparoscopic Fertility Sparing Management of Cervical Cancer

    PubMed Central

    Facchini, Chiara; Rapacchia, Giuseppina; Montanari, Giulia; Casadio, Paolo; Pilu, Gianluigi; Seracchioli, Renato

    2014-01-01

    Fertility can be preserved after conservative cervical surgery. We report on a 29-year-old woman who was obese, para 0, and diagnosed with cervical insufficiency at the first trimester of current pregnancy due to a previous trachelectomy. She underwent laparoscopic transabdominal cervical cerclage (LTCC) for cervical cancer. The surgery was successful and she was discharged two days later. The patient underwent a caesarean section at 38 weeks of gestation. Laparoscopic surgery is a minimally invasive approach associated with less pain and faster recovery, feasible even in obese women. PMID:24696772

  20. Nanotechnology in the management of cervical cancer.

    PubMed

    Chen, Jiezhong; Gu, Wenyi; Yang, Lei; Chen, Chen; Shao, Renfu; Xu, Kewei; Xu, Zhi Ping

    2015-03-01

    Cervical cancer is a major disease with high mortality. All cervical cancers are caused by infection with human papillomaviruses (HPV). Although preventive vaccines for cervical cancer are successful, treatment of cervical cancer is far less satisfactory because of multidrug resistance and side effects. In this review, we summarize the recent application of nanotechnology to the diagnosis and treatment of cervical cancer as well as the development of HPV vaccines. Early detection of cervical cancer enables tumours to be efficiently removed by surgical procedures, leading to increased survival rate. The current method of detecting cervical cancer by Pap smear can only achieve 50% sensitivity, whereas nanotechnology has been used to detect HPVs with greatly improved sensitivity. In cervical cancer treatment, nanotechnology has been used for the delivery of anticancer drugs to increase treatment efficacy and decrease side effects. Nanodelivery of HPV preventive and therapeutic vaccines has also been investigated to increase vaccine efficacy. Overall, these developments suggest that nanoparticle-based vaccine may become the most effective way to prevent and treat cervical cancer, assisted or combined with some other nanotechnology-based therapy.

  1. Nanotechnology in the management of cervical cancer.

    PubMed

    Chen, Jiezhong; Gu, Wenyi; Yang, Lei; Chen, Chen; Shao, Renfu; Xu, Kewei; Xu, Zhi Ping

    2015-03-01

    Cervical cancer is a major disease with high mortality. All cervical cancers are caused by infection with human papillomaviruses (HPV). Although preventive vaccines for cervical cancer are successful, treatment of cervical cancer is far less satisfactory because of multidrug resistance and side effects. In this review, we summarize the recent application of nanotechnology to the diagnosis and treatment of cervical cancer as well as the development of HPV vaccines. Early detection of cervical cancer enables tumours to be efficiently removed by surgical procedures, leading to increased survival rate. The current method of detecting cervical cancer by Pap smear can only achieve 50% sensitivity, whereas nanotechnology has been used to detect HPVs with greatly improved sensitivity. In cervical cancer treatment, nanotechnology has been used for the delivery of anticancer drugs to increase treatment efficacy and decrease side effects. Nanodelivery of HPV preventive and therapeutic vaccines has also been investigated to increase vaccine efficacy. Overall, these developments suggest that nanoparticle-based vaccine may become the most effective way to prevent and treat cervical cancer, assisted or combined with some other nanotechnology-based therapy. PMID:25752817

  2. Clinical technique for invasive cervical root resorption

    PubMed Central

    Silveira, Luiz Fernando Machado; Silveira, Carina Folgearini; Martos, Josué; Piovesan, Edno Moacir; César Neto, João Batista

    2011-01-01

    This clinical case report describes the diagnosis and treatment of an external invasive cervical resorption. A 17-year-old female patient had a confirmed diagnosis of invasive cervical resorption class 4 by cone beam computerized tomography. Although, there was no communication with the root canal, the invasive resorption process was extending into the cervical and middle third of the root. The treatment of the cervical resorption of the lateral incisor interrupted the resorptive process and restored the damaged root surface and the dental functions without any esthetic sequelae. Both the radiographic examination and computed tomography are imperative to reveal the extent of the defect in the differential diagnosis. PMID:22144822

  3. Studying the Physical Function and Quality of Life Before and After Surgery in Patients With Stage I Cervical Cancer

    ClinicalTrials.gov

    2016-10-26

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma, Not Otherwise Specified; Lymphedema; Sexual Dysfunction and Infertility; Stage IA1 Cervical Cancer; Stage IA2 Cervical Cancer; Stage IB1 Cervical Cancer

  4. 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.

  5. Relationship of Specific Bacteria in the Cervical and Vaginal Microbiotas with Cervicitis

    PubMed Central

    Srinivasan, Sujatha; Fiedler, Tina L.; Morgan, Martin T.; Balkus, Jennifer E.; McClelland, R. Scott; Fredricks, David N.; Marrazzo, Jeanne M.

    2015-01-01

    Background Cervicitis is an inflammatory condition of the cervix associated with upper genital tract infection and reproductive complications. Although cervicitis can be caused by several known pathogens, the etiology frequently remains obscure. Here we investigate vaginal bacteria associated with bacterial vaginosis as potential causes of cervicitis. Methods Associations between vaginal bacteria and cervicitis were assessed in a retrospective case control study of women attending a Seattle STD clinic. Individual bacterial species were detected using two molecular methods: quantitative PCR (qPCR) and broad range 16S rRNA gene PCR with pyrosequencing. The primary finding from this initial study was evaluated using qPCR in a second cohort of Kenyan women. Results The presence of Mageeibacillus indolicus, formerly BVAB3, in the cervix was associated with cervicitis, while the presence of Lactobacillus jensenii was inversely associated. Quantities of these bacteria did not differ between cervicitis cases and controls, though in a model inclusive of presence and abundance, M. indolicus remained significantly associated with cervicitis after adjustment for other cervicitis-causing pathogens. M. indolicus was not associated with cervicitis in our study of Kenyan women, possibly due to differences in the clinical definition of cervicitis. Conclusions Colonization of the endocervix with M. indolicus may contribute to the clinical manifestations of cervicitis, but further study is needed to determine whether this finding is repeatable and applicable to diverse groups of women. Colonization of the cervix with L. jensenii could be a marker of health, perhaps reducing inflammation or inhibiting pathogenic infection. PMID:26267872

  6. Time dependent physical properties of semicrystalline poly(arylene ether ether ketone) (PEEK) above its glass transition temperature: Physical aging vs. secondary crystallization

    SciTech Connect

    Velikov, V.; Verma, R.; marand, H.

    1995-12-01

    We monitored the change in small strain short term isothermal creep compliance of semicrystalline. PEEK (T{sub g} {approx} 150{degrees}C - 165{degrees}C) at various temperatures from 120{degrees}C to 260{degrees}C. With increase of aging times creep curves are shifted to longer times, implying slowing down of the mechanical relaxation of the polymer. The isothermal horizontal shift rate is close to unity below and above T{sub g} and exhibits significant drop in the glass transition region.

  7. Integration of Cu-coated single-mode optical fiber into carbon/PEEK composite for distributed structural health monitoring based on Rayleigh backscatter reflectometry

    NASA Astrophysics Data System (ADS)

    Steffen, Milan; Schukar, Marcus

    2013-05-01

    In this paper a technique for integrating copper coated silica optical fibers into AS-4/PEEK composite for Structural Health Monitoring (SHM) is presented. The integration steps are described in detail. X-ray and microscopic images indicate a successfully integrated optical fiber which does not seem to affect the fiber/matrix distribution around it. Optical backscatter reflectometry shows losses of approximately 2dBm-1 along the integrated parts of the optical fiber due to temperature induced shrinkage of the composite.

  8. Bilateral cervical ribs in a Dobermann Pinscher.

    PubMed

    Ricciardi, M; De Simone, A; Gernone, F; Giannuzzi, P

    2015-01-01

    An 11-year-old intact female Doberman Pinscher was presented with the complaint of non-ambulatory tetraparesis. Clinical and neurological examination revealed a caudal cervical spinal cord disfunction (C6-T2 spinal cord segments). Magnetic resonance imaging and computed tomographic (CT) findings of the cervical spine were consistent with caudal cervical spondylomyelopathy (CSM). During the diagnostic work-up for the cervical spine, bilateral bone anomalies involving the seventh cervical vertebra and the first ribs were found on radiographs and CT examination. The rib anomalies found in this dog appear similar to cervical ribs widely described in human medicine. In people, cervical ribs are associated with a high rate of stillbirth, early childhood cancer, and can cause the thoracic outlet syndrome, characterized by neurovascular compression at level of superior aperture of the chest. In dogs, only some sporadic anatomopathological descriptions of cervical ribs exist. In this report the radiographic and CT findings of these particular vertebral and rib anomalies along with their relationships with adjacent vasculature and musculature are shown intravitam in a dog. Specific radiographic and CT findings described in this report may help in reaching a presumptive diagnosis of this anomaly. Finally, their clinical and evolutionary significance are discussed.

  9. Surgical Management of Cervical Spondylotic Myelopathy

    PubMed Central

    Hsu, Wesley; Dorsi, Michael J.; Witham, Timothy F.

    2010-01-01

    Cervical spondylosis is a common degenerative condition that is a significant cause of morbidity. This review discusses the pathophysiology and natural history of cervical spondylotic myelopathy and focuses on the current literature evaluating the clinical management of these patients. PMID:20191085

  10. 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 Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... drain. (a) Identification. A cervical drain is a device designed to provide an exit channel for...

  11. Cervical Spine MRI in Abused Infants.

    ERIC Educational Resources Information Center

    Feldman, Kenneth W.; And Others

    1997-01-01

    This study attempted to use cervical spine magnetic resonance imaging (MRI) to detect cord injury in 12 dead children with head injury from child abuse. Eighty percent of children autopsied had small cervical spine hemorrhages; MRI did not identify them and did not identify cord injury in any child studied, indicating that MRI scans are probably…

  12. 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. PMID:27479833

  13. Oral contraceptives, human papillomavirus and cervical cancer.

    PubMed

    La Vecchia, Carlo; Boccia, Stefania

    2014-03-01

    Oncogenic human papillomavirus is the key determinant of cervical cancer, but other risk factors interact with it to define individual risk. Among these, there is oral contraceptive (OC) use. A quantitative review of the link between OCs and cervical cancer was performed. Long-term (>5 year) current or recent OC use has been related to an about two-fold excess risk of cervical cancer. Such an excess risk, however, levels off after stopping use, and approaches unity 10 or more years after stopping. The public health implications of OC use for cervical cancer are limited. In any case, such implications are greater in middle-income and low-income countries, as well as in central and eastern Europe and Latin America, where cervical cancer screening and control remain inadequate.

  14. Mechanical and cellular processes driving cervical myelopathy

    PubMed Central

    Dolan, Roisin T; Butler, Joseph S; O’Byrne, John M; Poynton, Ashley R

    2016-01-01

    Cervical myelopathy is a well-described clinical syndrome that may evolve from a combination of etiological mechanisms. It is traditionally classified by cervical spinal cord and/or nerve root compression which varies in severity and number of levels involved. The vast array of clinical manifestations of cervical myelopathy cannot fully be explained by the simple concept that a narrowed spinal canal causes compression of the cord, local tissue ischemia, injury and neurological impairment. Despite advances in surgical technology and treatment innovations, there are limited neuro-protective treatments for cervical myelopathy, which reflects an incomplete understanding of the pathophysiological processes involved in this disease. The aim of this review is to provide a comprehensive overview of the key pathophysiological processes at play in the development of cervical myelopathy. PMID:26807352

  15. Cervical Vertebral Body Chordoma in a Cat.

    PubMed

    Hampel, R; Taylor-Brown, F; Priestnall, S L

    2016-05-01

    A 9-year-old, neutered female Maine Coon cat with a 6-week history of progressive ataxia was diagnosed with a cervical vertebral body mass using magnetic resonance imaging. The mass displaced and compressed the cervical spinal cord. The cat was humanely destroyed and necropsy examination confirmed a mass within the second cervical vertebral body. Microscopically, the mass was composed of large, clear, vacuolated ('physaliferous') cells. Immunohistochemically, the neoplastic cells expressed both cytokeratin and vimentin and the final diagnosis was a cervical, vertebral body chordoma. This is only the third report of a chordoma in this species and the first in this location. Chordoma should be considered as a potential differential diagnosis for tumours arising from the cervical vertebrae in the cat.

  16. Triapine, Cisplatin, and Radiation Therapy in Treating Patients With Cervical Cancer or Vaginal Cancer

    ClinicalTrials.gov

    2014-04-21

    Recurrent Cervical Cancer; Recurrent Vaginal Cancer; Stage IB Cervical Cancer; Stage II Vaginal Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage III Vaginal Cancer; Stage IVA Cervical Cancer; Stage IVA Vaginal Cancer; Stage IVB Cervical Cancer; Stage IVB Vaginal Cancer; Therapy-related Toxicity

  17. Reoperations Following Cervical Disc Replacement.

    PubMed

    Skovrlj, Branko; Lee, Dong-Ho; Caridi, John Michael; Cho, Samuel Kang-Wook

    2015-06-01

    Cervical disc replacement (CDR) has emerged as an alternative surgical option to cervical arthrodesis. With increasing numbers of patients and longer follow-ups, complications related to the device and/or aging spine are growing, leaving us with a new challenge in the management and surgical revision of CDR. The purpose of this study is to review the current literature regarding reoperations following CDR and to discuss about the approaches and solutions for the current and future potential complications associated with CDR. The published rates of reoperation (mean, 1.0%; range, 0%-3.1%), revision (mean, 0.2%; range, 0%-0.5%), and removal (mean, 1.2%; range, 0%-1.9%) following CDR are low and comparable to the published rates of reoperation (mean, 1.7%; range; 0%-3.4%), revision (mean, 1.5%; range, 0%-4.7%), and removal (mean, 2.0%; range, 0%-3.4%) following cervical arthrodesis. The surgical interventions following CDR range from the repositioning to explantation followed by fusion or the reimplantation to posterior foraminotomy or fusion. Strict patient selection, careful preoperative radiographic review and surgical planning, as well as surgical technique may reduce adverse events and the need for future intervention. Minimal literature and no guidelines exist for the approaches and techniques in revision and for the removal of implants following CDR. Adherence to strict indications and precise surgical technique may reduce the number of reoperations, revisions, and removals following CDR. Long-term follow-up studies are needed, assessing the implant survivorship and its effect on the revision and removal rates. PMID:26097667

  18. Post laminoplasty cervical kyphosis—Case report

    PubMed Central

    Dugoni, D.E.; Mancarella, C.; Landi, A.; Tarantino, R.; Ruggeri, A.G.; Delfini, R.

    2014-01-01

    INTRODUCTION Cervical kyphosis is a progressive cervical sagittal plane deformity that may cause a reduction in the ability to look horizontally, breathing and swallowing difficulties, sense of thoracic oppression and social isolation. Moreover, cervical kyphosis can cause myelopathy due to a direct compression by osteo-articular structures on the spinal cord or to a transitory ischaemic injury. The treatment of choice is surgery. The goals of surgery are: nervous structures decompression, cervical and global sagittal balance correction and vertebral stabilization and fusion. PRESENTATION OF CASE In October 2008 a 35 years old woman underwent surgical removal of a cervical-bulbar ependymoma with C1–C5 laminectomy and a C2–C5 laminoplasty. Five months after surgery, the patient developed a kyphotic posture, with intense neck and scapular girdle pain. The patients had a flexible cervical kyphosis. Therefore, we decided to perform an anterior surgical approach. We performed a corpectomy C4–C5 in order to achieve the anterior decompression; we placed a titanium expansion mesh. DISCUSSION Cervical kyphosis can be flexible or fixed. Some authors have reported the use of anterior surgery only for flexible cervical kyphosis as discectomy and corpectomy. This approach is useful for anterior column load sharing however it is not required for deformity correction. CONCLUSION The anterior approach is a good surgical option in flexible cervical kyphosis. It is of primary importance the sagittal alignment of the cervical spine in order to decompress the nervous structures and to guarantee a long-term stability. PMID:25462050

  19. Cervical disc hernia operations through posterior laminoforaminotomy

    PubMed Central

    Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit

    2016-01-01

    Objective: The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. Materials and Methods: We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. Results: The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years). Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%). On control examinations, there was no finding of instability or cervical kyphosis. Conclusion: Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis. PMID:27217655

  20. 21 CFR 884.4260 - Hygroscopic Laminaria cervical dilator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hygroscopic Laminaria cervical dilator. 884.4260 Section 884.4260 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... cervical dilator is a device designed to dilate (stretch open) the cervical os by cervical insertion of...

  1. 21 CFR 884.1040 - Viscometer for cervical mucus.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Viscometer for cervical mucus. 884.1040 Section... Devices § 884.1040 Viscometer for cervical mucus. (a) Identification. A viscometer for cervical mucus is a device that is intended to measure the relative viscoelasticity of cervical mucus collected from a...

  2. 21 CFR 884.1040 - Viscometer for cervical mucus.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Viscometer for cervical mucus. 884.1040 Section... Devices § 884.1040 Viscometer for cervical mucus. (a) Identification. A viscometer for cervical mucus is a device that is intended to measure the relative viscoelasticity of cervical mucus collected from a...

  3. 21 CFR 884.1040 - Viscometer for cervical mucus.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Viscometer for cervical mucus. 884.1040 Section... Devices § 884.1040 Viscometer for cervical mucus. (a) Identification. A viscometer for cervical mucus is a device that is intended to measure the relative viscoelasticity of cervical mucus collected from a...

  4. 21 CFR 884.4250 - Expandable cervical dilator.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Expandable cervical dilator. 884.4250 Section 884....4250 Expandable cervical dilator. (a) Identification. An expandable cervical dilator is an instrument with two handles and two opposing blades used manually to dilate (stretch open) the cervical os....

  5. 21 CFR 884.4250 - Expandable cervical dilator.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Expandable cervical dilator. 884.4250 Section 884....4250 Expandable cervical dilator. (a) Identification. An expandable cervical dilator is an instrument with two handles and two opposing blades used manually to dilate (stretch open) the cervical os....

  6. 21 CFR 884.4250 - Expandable cervical dilator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Expandable cervical dilator. 884.4250 Section 884....4250 Expandable cervical dilator. (a) Identification. An expandable cervical dilator is an instrument with two handles and two opposing blades used manually to dilate (stretch open) the cervical os....

  7. 21 CFR 884.1040 - Viscometer for cervical mucus.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Viscometer for cervical mucus. 884.1040 Section... Devices § 884.1040 Viscometer for cervical mucus. (a) Identification. A viscometer for cervical mucus is a device that is intended to measure the relative viscoelasticity of cervical mucus collected from a...

  8. 21 CFR 884.4250 - Expandable cervical dilator.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Expandable cervical dilator. 884.4250 Section 884....4250 Expandable cervical dilator. (a) Identification. An expandable cervical dilator is an instrument with two handles and two opposing blades used manually to dilate (stretch open) the cervical os....

  9. 21 CFR 884.4250 - Expandable cervical dilator.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Expandable cervical dilator. 884.4250 Section 884....4250 Expandable cervical dilator. (a) Identification. An expandable cervical dilator is an instrument with two handles and two opposing blades used manually to dilate (stretch open) the cervical os....

  10. 21 CFR 884.1040 - Viscometer for cervical mucus.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Viscometer for cervical mucus. 884.1040 Section... Devices § 884.1040 Viscometer for cervical mucus. (a) Identification. A viscometer for cervical mucus is a device that is intended to measure the relative viscoelasticity of cervical mucus collected from a...

  11. Anterior Cervical Spine Surgery for Degenerative Disease: A Review

    PubMed Central

    SUGAWARA, Taku

    Anterior cervical spine surgery is an established surgical intervention for cervical degenerative disease and high success rate with excellent long-term outcomes have been reported. However, indications of surgical procedures for certain conditions are still controversial and severe complications to cause neurological dysfunction or deaths may occur. This review is focused mainly on five widely performed procedures by anterior approach for cervical degenerative disease; anterior cervical discectomy, anterior cervical discectomy and fusion, anterior cervical corpectomy and fusion, anterior cervical foraminotomy, and arthroplasty. Indications, procedures, outcomes, and complications of these surgeries are discussed. PMID:26119899

  12. Invasive Cervical Resorption: A Review

    PubMed Central

    Kandalgaonkar, Shilpa D; Gharat, Leena A; Tupsakhare, Suyog D; Gabhane, Mahesh H

    2013-01-01

    Invasive cervical resorption is a relatively uncommon form of external root resorption exhibiting no external signs. The resorptive condition is often detected by routine radiographic examination. The clinical features vary from a small defect at the gingival margin to a pink coronal discoloration of the tooth crown resulting in ultimate cavitation of the overlying enamel which is painless unless pulpal or periodontal infection supervenes. Radiographic features of lesions vary from well-delineated to irregularly bordered mottled radiolucencies, and these can be confused with dental caries. A characteristic radiopaque line generally separates the image of the lesion from that of the root canal, because the pulp remains protected by a thin layer of predentin until late in the process. Histopathologically, the lesions contain fibrovascular tissue with resorbing clastic cells adjacent to the dentin surface. More advanced lesions display fibro-osseous characteristics with deposition of ectopic bonelike calcifications both within the resorbing tissue and directly on the dentin surface. How to cite this article: Kandalgaonkar SD, Gharat LA, Tupsakhare SD, Gabhane MH. Invasive Cervical Resorption: A Review. J Int Oral Health 2013;5(6):124-30 . PMID:24453457

  13. Network Topologies Decoding Cervical Cancer

    PubMed Central

    Jalan, Sarika; Kanhaiya, Krishna; Rai, Aparna; Bandapalli, Obul Reddy; Yadav, Alok

    2015-01-01

    According to the GLOBOCAN statistics, cervical cancer is one of the leading causes of death among women worldwide. It is found to be gradually increasing in the younger population, specifically in the developing countries. We analyzed the protein-protein interaction networks of the uterine cervix cells for the normal and disease states. It was found that the disease network was less random than the normal one, providing an insight into the change in complexity of the underlying network in disease state. The study also portrayed that, the disease state has faster signal processing as the diameter of the underlying network was very close to its corresponding random control. This may be a reason for the normal cells to change into malignant state. Further, the analysis revealed VEGFA and IL-6 proteins as the distinctly high degree nodes in the disease network, which are known to manifest a major contribution in promoting cervical cancer. Our analysis, being time proficient and cost effective, provides a direction for developing novel drugs, therapeutic targets and biomarkers by identifying specific interaction patterns, that have structural importance. PMID:26308848

  14. Epidemiology and Early Detection of Cervical Cancer.

    PubMed

    Hillemanns, Peter; Soergel, Phillip; Hertel, Hermann; Jentschke, Matthias

    2016-01-01

    The new German S3 guideline 'Prevention of Cervical Cancer' published in 2016 is based on the latest available evidence about cervical cancer screening and treatment of cervical precancer. Large randomized controlled trials indicate that human papillomavirus (HPV)-based screening may provide better protection against cervical cancer than cytology alone through improved detection of premalignant disease in the first screening round prior to progression. Therefore, women aged 30 years and older should preferably be screened with HPV testing every 3-5 years (cytology alone every 2 years is an acceptable alternative). Co-testing is not recommended. Screening should start at 25 years using cytology alone every 2 years. The preferred triage test after a positive HPV screening test is cytology. Women positive for HPV 16 and HPV 18 should receive immediate colposcopy. Another alternative triage method is p16/Ki-67 dual stain cytology. The mean yearly participation rate in Germany is between 45 and 50%. Offering devices for HPV self-sampling has the potential to increase participation rates in those women who are at higher risk of developing cervical cancer. Regarding primary prevention, the 9-valent vaccine may provide protection against up to 85% of cervical intraepithelial neoplasia (CIN) 3 and 90% of cervical cancer, and is available in Europe as a 2-dose schedule from May 2016. PMID:27614953

  15. Conservative Surgery for Early Cervical Cancer.

    PubMed

    Rema, P; Ahmed, Iqbal

    2016-09-01

    There is a rising incidence of early cervical cancer in young patients as a result of screening and early detection. Treatment of cervical cancer by surgery or radiotherapy results in permanent infertility which affects the quality of life of cancer survivors. Now with improved survival rates among early cervical cancer patients, conservative surgery aiming at fertility preservation in those desiring future pregnancy is an accepted treatment. Conservative surgery is possible in early cervical cancer including micro invasive cancer and stage IB cancers less than 2 cm. Stage IA1 cervical cancer is treated effectively by cervical conisation. In stage IA2 cancers and stage IB1 cancers less than 2 cm the fertility preservation surgery is radical trachelectomy. Radical trachelectomy removes the cervix with medial parametrium and upper 2 cm vaginal cuff retaining the uterus and adnexa to allow future pregnancy. Radical trachelectomy is a safe procedure in selected patients with cancer cervix with acceptable oncologic risks and promising obstetric outcome. It should be avoided in tumours larger than 2 cm and aggressive histologic types. This article focuses on the current options of conservative surgery in early cervical cancer. PMID:27651696

  16. Fatal Cervical Spine Injury From Diving Accident.

    PubMed

    Voland, Christelle; Vilarino, Raquel; Grabherr, Silke; Lobrinus, Johannes Alexander; Palmiere, Cristian

    2015-09-01

    Spinal cord injuries result after diving into shallow water, often after incautious jumps head first into water of unknown depth during recreational or sport activities. Mortality is generally due to upper cervical trauma. The authors present a case of a diving-related death in a young woman who underwent medicolegal investigations. The measured water depth at the supposed dive site was 1.40 m. Postmortem radiology and autopsy revealed fractures of the body and the posterior arch of the fifth cervical vertebra, a fracture of the right transverse process of the sixth cervical vertebra and hemorrhages involving the cervical paraspinal muscles. Neuropathology showed a posterior epidural hematoma involving the whole cervical region and a symmetric laceration of the spinal cord located at the fourth and fifth cervical vertebra level, surrounded by multiple petechial hemorrhages. Toxicology revealed the presence of ethanol in both blood and urine samples. The death was attributed to cervical spine fracture (C5-C6), spinal cord contusion, and subsequent drowning. This case highlights the usefulness of postmortem radiology, examination of the deep structures of the neck, toxicology, neuropathology, and a detailed research of signs of drowning to formulate appropriate hypotheses pertaining to the cause and mechanism of death.

  17. Prognosis for Patients With Traumatic Cervical Spinal Cord Injury Combined With Cervical Radiculopathy

    PubMed Central

    Kim, Seo Yeon; Kim, Tae Uk; Lee, Seong Jae

    2014-01-01

    Objective To delineate cervical radiculopathy that is found in combination with traumatic cervical spinal cord injury (SCI) and to determine whether attendant cervical radiculopathy affects the prognosis and functional outcome for SCI patients. Methods A total of 66 patients diagnosed with traumatic cervical SCI were selected for neurological assessment (using the International Standards for the Neurological Classification of Spinal Cord Injury [ISNCSCI]) and functional evaluation (based on the Korean version Modified Barthel Index [K-MBI] and Functional Independence Measure [FIM]) at admission and upon discharge. All of the subjects received a preliminary electrophysiological assessment, according to which they were divided into two groups as follows: those with cervical radiculopathy (the SCI/Rad group) and those without (the SCI group). Results A total of 32 patients with cervical SCI (48.5%) had cervical radiculopathy. The initial ISNCSCI scores for sensory and motor, K-MBI, and total FIM did not significantly differ between the SCI group and the SCI/Rad group. However, at discharge, the ISNCSCI scores for motor, K-MBI, and FIM of the SCI/Rad group showed less improvement (5.44±8.08, 15.19±19.39 and 10.84±11.49, respectively) than those of the SCI group (10.76±9.86, 24.79±19.65 and 17.76±15.84, respectively) (p<0.05). In the SCI/Rad group, the number of involved levels of cervical radiculopathy was negatively correlated with the initial and follow-up motors score by ISNCSCI. Conclusion Cervical radiculopathy is not rare in patients with traumatic cervical SCI, and it can impede neurological and functional improvement. Therefore, detection of combined cervical radiculopathy by electrophysiological assessment is essential for accurate prognosis of cervical SCI patients in the rehabilitation unit. PMID:25229022

  18. [Induction chemotherapy for locally advanced cervical cancer].

    PubMed

    Morkhov, K Yu; Nechushkina, V M; Kuznetsov, V V

    2015-01-01

    The main methods of treatment for cervical cancer are surgery, radiotherapy or their combination. During past two decades chemotherapy are increasingly being used not only in patients with disseminated forms of this disease but also in patients undergoing chemoradiotherapy or as induction therapy. Possibilities of adjuvant chemotherapy for cervical cancer are being studied. According to A.D.Kaprin and V.V. Starinskiy in 2013 in Russia, 32% of patients with newly diagnosed cervical cancer underwent only radiation therapy, 32%--combined or complex treatment, 27.3%--only surgery, and just 8.7%--chemoradiotherapy. PMID:26087600

  19. Cervical sprains, disc herniations, minor fractures, and other cervical injuries in the athlete.

    PubMed

    Zmurko, Matthew G; Tannoury, Tony Y; Tannoury, Chadi A; Anderson, D Greg

    2003-07-01

    In today's health-conscious society, more people are participating in athletic endeavors. As participation increases, so does the incidence of cervical injuries. Fortunately, most of the cervical injuries seen in sports are minor and can be treated successfully with minimal morbidity. It is important, however, to accurately assess the patient sustaining a cervical injury to rule out the presence of a more severe cervical injury. When practitioners understand the pathophysiology and treatment of common injuries, including sprains, strains, contusions, disc herniations, and simple fractures, most athletes can be returned to full function.

  20. Cisplatin and Radiation Therapy With or Without Triapine in Treating Patients With Previously Untreated Stage IB-IVA Cervical Cancer or Stage II-IVA Vaginal Cancer

    ClinicalTrials.gov

    2016-03-25

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma; Stage IB2 Cervical Cancer; Stage II Vaginal Cancer; Stage IIA1 Cervical Cancer; Stage IIA2 Cervical Cancer; Stage IIB Cervical Cancer; Stage III Vaginal Cancer; Stage IIIA Cervical Cancer; Stage IIIB Cervical Cancer; Stage IVA Cervical Cancer; Stage IVA Vaginal Cancer; Vaginal Adenocarcinoma; Vaginal Adenosquamous Carcinoma; Vaginal Squamous Cell Carcinoma

  1. Cisplatin and Radiation Therapy With or Without Carboplatin and Paclitaxel in Patients With Locally Advanced Cervical Cancer

    ClinicalTrials.gov

    2016-10-26

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Squamous Cell Carcinoma; Chemotherapeutic Agent Toxicity; Cognitive Side Effects of Cancer Therapy; Psychological Impact of Cancer; Radiation Toxicity; Sexual Dysfunction and Infertility; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  2. Hybrid Strategy of Two-Level Cervical Artificial Disc and Intervertebral Cage: Biomechanical Effects on Tissues and Implants.

    PubMed

    Chung, Tzu-Tsao; Hueng, Dueng-Yuan; Lin, Shang-Chih

    2015-11-01

    This numerical study aimed to evaluate tissue and implant responses to the hybrid surgery (HS) of cervical artificial disc replacement (C-ADR) and anterior cervical discectomy and fusion (ACDF).Four hybrid strategies of two-level C-ADR and ACDF were compared in terms of adjacent segment degeneration (ASD) and implant failure.The rotary C-ADR and semirigid ACDF have been extensively used in the multilevel treatment of cervical instability and degeneration, but the constrained mobility at the ACDF segments can induce postoperative ASD problems. Hybrid surgery of C-ADR and ACDF has been an alternative to provide the optimal tradeoff between surgical cost and ASD problems. The biomechanical effects of hybrid strategies warrant thorough investigation for the two-level instrumentation.Based on computed tomography imaging, a nonlinear C2-C7 model was developed and validated by cadaveric and numerical data. Four strategies of inserting the C-ADR and ACDF into the C4-C6 segments were systematically arranged as PP (2 peek cages), AA (2 artificial discs), PA, and AP. The biomechanical behavior of these 4 strategies was evaluated in terms of motion and stresses of discs, facet forces, stresses of C-ADR and ACDF, and C-ADR motion.The constrained mobility of the ACDF segment worsened the kinematic and mechanical demands of the adjacent segments and artificial discs. The C-ADR articulation provided higher mobility than the replaced disc of the intact construct, making it an effective buffer to accommodate the compensated mobility and load from the ACDF segment. Consequently, the ASD progression of the AA construct was most restricted, followed by the PA, AP, and PP construct.The PA strategy is a tradeoff to preserve mobility and reduce cost. The C-ADR of the PA construct preserves the mobility of the C5/C6 segment and shares the transferred motion and loads of the fused C4/C5 segment. The PA construct shows optimal biomechanical results for minimizing ASD and implant failure

  3. Cervicitis

    MedlinePlus

    ... include: Avoid irritants such as douches and deodorant tampons. Make sure that any foreign objects you insert into your vagina (such as tampons) are properly placed. Be sure to follow instructions ...

  4. [Cervical cancer: particularities in HIV patients].

    PubMed

    Grellier, Noémie; Quéro, Laurent

    2014-11-01

    Cervical cancer is the second most common cancer in women worldwide. It represents one of the most challenging public health problems in developing countries. HIV-infected women have a higher risk of cervical cancer which is an AIDS defining cancer. Cervical cancer treatment in HIV-infected and non-infected women is the same. HIV naive women must be prescribed combination antiretroviral therapy at the moment of HIV cancer diagnosis. A close collaboration between oncologist and infectiologist is mandatory to optimize HIV treatment. Among HIV-infected women, PAP-smear screening for early detection and treatment of precancerous cervical lesions is recommended. HPV vaccination is also recommended with the same efficacy and safety profile as the general population.

  5. Cervical Human Papillomavirus Screening among Older Women

    PubMed Central

    Grainge, Matthew J.; Seth, Rashmi; Guo, Li; Neal, Keith R.; Coupland, Carol; Vryenhoef, Paul; Johnson, Jane; Jenkins, David

    2005-01-01

    Rates of acquisition and clearance of cervical human papillomavirus (HPV) during a 3-year period in women 51 years of age were compared with rates in younger women to provide data on cervical screening for women >50 years of age. Paired, cytologically negative, archived cervical smears taken 3 years apart from 710 women in Nottingham, United Kingdom, were retrieved and tested for HPV infection with polymerase chain reaction (PCR) with GP5+/6+ primers. Seventy-one (21.3%) of 333 women 51 years of age who were HPV negative at baseline were positive 3 years later. This percentage was higher than the corresponding acquisition rates among women 21 (15.2%), 31 (14.1%), and 41 (13.3%) years of age, although these differences were not significant. This retrospective study shows that HPV-negative women >50 years of age can acquire HPV and, therefore, require cervical screening. PMID:16318718

  6. Traumatic cervical spine fractures in the adult.

    PubMed

    Copley, Phillip; Tilliridou, Vicky; Jamjoom, Aimun

    2016-09-01

    This article reviews fractures of the cervical spine, highlighting the pertinent goals of initial management, the indications for different imaging modalities and the different fracture patterns. Basic principles of management of these different fracture patterns are outlined. PMID:27640656

  7. Airway management in cervical spine injury

    PubMed Central

    Austin, Naola; Krishnamoorthy, Vijay; Dagal, Arman

    2014-01-01

    To minimize risk of spinal cord injury, airway management providers must understand the anatomic and functional relationship between the airway, cervical column, and spinal cord. Patients with known or suspected cervical spine injury may require emergent intubation for airway protection and ventilatory support or elective intubation for surgery with or without rigid neck stabilization (i.e., halo). To provide safe and efficient care in these patients, practitioners must identify high-risk patients, be comfortable with available methods of airway adjuncts, and know how airway maneuvers, neck stabilization, and positioning affect the cervical spine. This review discusses the risks and benefits of various airway management strategies as well as specific concerns that affect patients with known or suspected cervical spine injury. PMID:24741498

  8. NIH Research Leads to Cervical Cancer Vaccine

    MedlinePlus

    ... Transmitted Diseases NIH Research Leads to Cervical Cancer Vaccine Past Issues / Fall 2008 Table of Contents For ... Douglas Lowy (left) and John Schiller developed the vaccine to prevent HPV infection in women, the cause ...

  9. Midline cervical cleft. A case report.

    PubMed

    Ikuzawa, M; Matsumoto, K; Amino, K; Sakuda, M

    1992-10-01

    A case of incomplete midline cervical cleft of the upper neck is reported. It showed histological resemblance to a mature teratoma with three different germ-cell components, including cartilage, striated muscles, small salivary glands, and nerves.

  10. Unmet clinical needs in cervical cancer screening.

    PubMed

    Rao, Jianyu; Escobar-Hoyos, Luisa; Shroyer, Kenneth R

    2016-01-01

    Cancer rates worldwide are expected to increase disproportionally in coming decades relative to the projected increase in population, especially in the developing world. The general unavailability of the Pap test and the cost of the HPV test in the developing world have precluded the deployment of effective cervical cancer screening programs in many developing countries. Recent improvements in testing technology arise from a need to overcome the significant limitations of the Pap test and HPV test, but results require first-world technology and validation. Developing countries, where cervical cancer remains one of the most important causes of cancer death, have the greatest need for an affordable, easy-to-use, and highly reliable cancer screening method that can return a diagnosis through efficient laboratory analysis or, more easily, at a woman's point of care. While research, testing, and vaccine improvements in recent years continue to lower the incidence of cervical cancer in some developed countries such as the U.S., HPV testing research needs to do more than test for the presence of virus. The tests must determine the presence and progression of cervical disease. Tests should be more sensitive and specific than Pap tests and Pap-related tests, and should be accurate in more than 90 percent of cases. Tests also need to be low-cost, objective, and easy to perform so screening programs can be widely implemented in developing countries where the need for a better cervical cancer screening test is highest. Such tests may be available through the recent advances in specific biomarkers of cervical cancer and multiplex detection technologies. Development of the next generation of cervical cancer tests that are more specific, sensitive, and informative than the traditional Pap or HPV test will make a significant impact on the reduction of cervical cancer worldwide.

  11. Cervical intra-/extramedullary solitary fibrous tumour.

    PubMed

    Ogungbo, B; Prakash, S; Kulkarni, G; Bradey, N; Marks, S M; Scoones, D

    2005-06-01

    A 53-year-old man presented with a 9-month history of symptoms of right-sided weakness, tingling and hypersentivity to clothes on both sides of the body. MRI revealed a large intraspinal intradural tumour at the level of C3-C4 in the cervical cord. The final histology was a solitary fibrous tumour (SFT) of the cervical spinal cord. The radiological diagnosis, surgical management and histology are reviewed.

  12. Cervical cancer: A comprehensive approach towards extermination.

    PubMed

    Bava, Smitha V; Thulasidasan, Arun Kumar T; Sreekanth, Chanickal N; Anto, Ruby John

    2016-01-01

    Human Papilloma Virus (HPV) is one of the most common sexually transmitted pathogen, globally. Oncogenic types of HPV are the causative agents of many neoplastic diseases, including cervical cancer, which ranks as the most common cancer affecting females in developing countries. HPV infection of the cervical epithelium and the subsequent integration of viral DNA into the host genome are the major risk factors for cervical cancer. The scientific discovery of HPV as the causal agent of cervical cancer has led to the development of HPV-based diagnostic tools. Prophylactic vaccines, based on the oncogenic HPV type virus-like particles have been introduced in several developed countries as a preliminary preventive approach. Nevertheless, it remains a continuous threat to women in developing countries, where the prophylactic vaccines are unaffordable and organized screening programmes are lacking. This warrants implementation of prevention strategies that will reduce cervical cancer-related mortality. In this review, we have discussed molecular pathogenesis of HPV infection and the risk factors associated with it. The diagnosis, treatment and prevention strategies of HPV-related cervical cancer have also been discussed.

  13. The Future of Vaccines for Cervical Cancer

    PubMed Central

    Huh, Warner K.; Roden, Richard B.S.

    2015-01-01

    Cervical cancer continues to cause significant morbidity and mortality worldwide, making prophylactic cervical cancer vaccines an important focus for cervical cancer prevention. The increasing accessibility of these vaccines worldwide has the potential to greatly decrease the incidence and burden of disease in the future. However, current prophylactic vaccines offer no therapeutic benefit for persons already infected with human papillomavirus types targeted by vaccines or persons with precancerous lesions or cervical cancer. The protection offered by current vaccines is primarily against human papillomavirus types used to derive the vaccine, although partial cross-protection for related virus types has been observed. Herein, we describe findings from preclinical and clinical studies that employ vaccine strategies that have the potential to shape the future of vaccines against cervical cancer. Modalities include prophylactic strategies to target more oncogenic virus types by using the minor capsid antigen L2 and/or by increasing the number of types used to derive virus-like particle vaccines. Therapeutic strategies include the development of vaccines against human papillomavirus early proteins (targets for cellular immunity) for the resolution of precancerous lesions and cervical cancer. Future applications of existing VLP-based vaccines are also discussed. PMID:18482559

  14. Anterior cervical hypertrichosis: a sporadic case

    PubMed Central

    Bostan, Sezen; Yaşar, Şirin; Serdar, Zehra Aşiran; Gizlenti, Sevda

    2016-01-01

    Anterior cervical hypertrichosis is a very rare form of primary localized hypertrichosis. It consists of a tuft of terminal hair on the anterior neck just above the laryngeal prominence. The etiology is still unknown. In this article, we reported a 15-year-old female patient who presented to our clinic with a complaint of hypertrichosis on the anterior aspect of the neck for the last five years. Her past medical history revealed no pathology except for vesicoureteral reflux. On the basis of clinical presentation, our patient was diagnosed with anterior cervical hypertrichosis and she was considered to be a sporadic case due to lack of other similar cases in familial history. To date, 33 patients with anterior cervical hypertrichosis have been reported. Anterior cervical hypertrichosis can be associated with other abnormalities, but it frequently presents as an isolated defect (70%). The association of vesicoureteral reflux and anterior cervical hypertrichosis which was observed in our patient might be coincidental. So far, no case of anterior cervical hypertrichosis associated with vesicoureteral reflux has been reported in the literature. PMID:27103865

  15. Simple trachelectomy during pregnancy for cervical cancer

    PubMed Central

    Moreno-Luna, Estefania; Alonso, Patricia; Santiago, Javier De; Zapardiel, Ignacio

    2016-01-01

    Invasive cervical cancer is rare during a pregnancy, even though it is one of the most frequently diagnosed neoplasias during that time. It is noted that around 30% of women diagnosed with cervical cancer are of reproductive age. This means that up to 3% of cases of cervical cancer are found in pregnant women or those who are in the post-birth period. A cervicovaginal Pap smear is performed as part of the regular checkup for a pregnant woman during the first visit so that cervical cancer can easily be diagnosed early in these women, detecting it early in up to 70–80% of cases. We present here the case of a patient with initial diagnosis of cervical cancer made around 20th week of pregnancy. It was then treated by a simple trachelectomy and cerclage during week 24. The pregnant woman gave birth to a healthy baby at the end of her pregnancy. Definitive treatment was completed three months after giving birth with a total hysterectomy and laparoscopic bilateral salpingectomy while preserving both ovaries. After 17 months of monitoring the patient showed no signs of reoccurrence. In conclusion, during the early stage of cervical cancer conservative management may be a reasonable option to preserve the current pregnancy. PMID:27610199

  16. Cervical radiculopathy: epidemiology, etiology, diagnosis, and treatment.

    PubMed

    Woods, Barrett I; Hilibrand, Alan S

    2015-06-01

    Cervical radiculopathy is a relatively common neurological disorder resulting from nerve root dysfunction, which is often due to mechanical compression; however, inflammatory cytokines released from damaged intervertebral disks can also result in symptoms. Cervical radiculopathy can often be diagnosed with a thorough history and physical examination, but an magnetic resonance imaging or computed tomographic myelogram should be used to confirm the diagnosis. Because of the ubiquity of degenerative changes found on these imaging modalities, the patient's symptoms must correlate with pathology for a successful diagnosis. In the absence of myelopathy or significant muscle weakness all patients should be treated conservatively for at least 6 weeks. Conservative treatments consist of immobilization, anti-inflammatory medications, physical therapy, cervical traction, and epidural steroid injections. Cervical radiculopathy typically is self-limiting with 75%-90% of patients achieving symptomatic improvement with nonoperative care. For patients who are persistently symptomatic despite conservative treatment, or those who have a significant functional deficit surgical treatment is appropriate. Surgical options include anterior cervical decompression and fusion, cervical disk arthroplasty, and posterior foraminotomy. Patient selection is critical to optimize outcome. PMID:25985461

  17. Cervical cancer: disease prevention and informational support.

    PubMed

    Schwartz, Lindsay Ashley

    2009-01-01

    Cervical cancer and Human Papillomavirus (HPV) are significant health care concerns for women worldwide. Globally, in 2006, cervical cancer remains the second most common cancer in women. Infection with high-risk strains of HPV is found to be present in approximately 99% of cervical cancer cases. The Supportive Care Framework developed by Fitch (2008) will serve as a guide to the paper. The need for informational support and disease prevention initiatives will be explored. Knowledge and awareness of HPV and its link to cervical cancer amongst the general population are low. Once women are made aware of the relationship between HPV and cervical cancer, they want more information on disease prevention, transmission, detection, treatment information, symptoms and risk for developing cancer. Evidence-based nursing interventions that focus on meeting the informational needs of women and increasing awareness of HPV and cervical cancer will be proposed. Information on HPV-prophylactic vaccines and Papanicolaou (PAP) screening as primary and secondary disease prevention strategies will be discussed.

  18. Intrapartum Cervical Laceration and Subsequent Pregnancy Outcomes

    PubMed Central

    Wong, Luchin F.; Wilkes, Jacob; Korgenski, Kent; Varner, Michael W.; Manuck, Tracy A.

    2016-01-01

    Objective The objective of this study was to describe pregnancy outcomes, including cervical insufficiency and preterm birth, in the subsequent pregnancy following an intrapartum cervical laceration. Study Design Retrospective cohort of women with their first two consecutive singleton pregnancies carried to ≥ 200/7 weeks' gestation within a tertiary health care system from 2002 to 2012. Cervical laceration cases were identified by ICD9 codes and included if suture repair was required. Results In this study, 55 women were confirmed to have a cervical laceration in the first delivery; 43 lacerations after vaginal delivery (VD) and 12 after cesarean delivery (CD). The median gestational age of the first delivery was 400/7 weeks and the median birth weight 3,545 g; these did not differ between VD and CD. In the second pregnancy, 2 of 55 women (4.6%) had a prophylactic cerclage placed; 1 carried to term and the other delivered at 356/7 weeks. In total, four women (9.3%) delivered the second pregnancy < 37 weeks: three had a prior term VD and one had a prior 34 weeks VD. There was only one case of recurrent cervical laceration, occurring in the setting of vaginal deliveries. Conclusion Obstetric cervical lacerations are uncommon. Complications in the following pregnancy were low, despite lack of additional prophylactic cerclage use. PMID:27621953

  19. Cervical cerclage: a review of the evidence.

    PubMed

    Fox, Nathan S; Chervenak, Frank A

    2008-01-01

    Cervical insufficiency is a difficult and confusing diagnosis. Its diagnostic criteria, etiology, and treatment are all debated. Cervical cerclage has been a common practice in obstetrics since it was first described by Shirodker and then McDonald in the 1950s. Cerclages have been placed because of a patient's obstetrical history, physical examination, ultrasound, or a combination of the above. However, the data supporting cerclage placement is limited. There has never been a prospective, randomized, controlled trial of cerclage versus no cerclage in patients with a classic history of cervical insufficiency (multiple painless second trimester losses occurring at progressively earlier gestational ages). This article attempts to review the relevant studies regarding cerclage placement for the treatment of cervical insufficiency. Based on the current literature, there is evidence supporting cervical cerclage in the following limited circumstances: a history of 3 or more spontaneous preterm births or second trimester losses; a high-risk patient with a singleton pregnancy who has a short cervix in the second trimester. Because the majority of patients with risk factors for preterm birth and second trimester loss (poor obstetric history, short cervix) will still deliver at term or near-term, studies on the effectiveness of cervical cerclage would need many patients to be powered appropriately.

  20. Cervical cancer: screening and therapeutic perspectives.

    PubMed

    Sankaranarayanan, Rengaswamy; Thara, Somanathan; Esmy, Pulikottil Okkuru; Basu, Partha

    2008-01-01

    Cervical cancer is a major cause of mortality and premature death among women in their most productive years in low- and medium-resourced countries in Asia, Africa and Latin America, despite the fact that it is an eminently preventable cancer. While cytology screening programmes have resulted in a substantial reduction of cervical cancer mortality in developed countries, they have been shown to have a wide range of sensitivity in most routine settings including in developing countries. Although liquid-based cytology improves sample adequacy, claims on improved sensitivity remain controversial. Human papillomavirus testing is more sensitive than cytology, but whether this gain represents protection against future cervical cancer is not clear. Recently, in a randomized trial, the use of visual inspection with 4% acetic acid was shown to reduce cervical cancer incidence and mortality. Cryotherapy and large loop excision of the transformation zone are effective and safe treatment methods for cervical intraepithelial neoplasia. The clinical stage of cancer is the single most important prognostic factor and should be carefully evaluated in choosing optimal treatment between surgery and radiotherapy, with or without chemotherapy. At the public health level, health care infrastructure, affordability and capacity for initiating and sustaining vaccination and screening programmes are critical factors in cervical cancer control. On the other hand, an informed practitioner can utilize the multiple opportunities in routine primary care interactions for prevention, screening, early detection and prompt referral for treatment. PMID:18685274