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1

Coblation of spinal endplates in preparation for interbody spinal fusion  

Microsoft Academic Search

Posterior lumbar interbody fusion (PLIF) and anterior lumbar interbody fusion (ALIF) have become routine alternatives to intertransverse process fusion. The use of Coblation® (ArthroCare Corporation, Sunnyvale, CA) allows for routine and reproducible removal of cartilaginous endplate down to the bony endplate. Our experience with this new technology is reviewed. The authors used Coblation® to prepare endplates of 10 consecutive patients

Henry E. Aryan; Christopher P. Ames; Bartek Szandera; Andrew D. Nguyen; Frank L. Acosta; William R. Taylor

2006-01-01

2

Failed anterior lumbar interbody fusion due to incomplete foraminal decompression  

Microsoft Academic Search

Background  Anterior lumbar interbody fusion (ALIF) has gained widespread popularity for spinal disorders requiring fusion. The purpose\\u000a of this study was to analyze ALIF failures.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  The medical records of 223 patients treated with ALIF between January 2007 and June 2008 were retrospectively reviewed. Patients\\u000a with unfavorable outcomes, including subsequent posterior decompression at the index level or poor outcomes after ALIF were

Kyung-Chul Choi; Yong Ahn; Byung-Uk Kang; Joo-Hee Jang; Kyeong-Ki Kim; Yong Hwan Shin; Jong-Oh Choi; Sang-Ho Lee

2011-01-01

3

Anterior lumbar interbody fusion with LT-cages  

Microsoft Academic Search

Purpose of study: Workers compensation status is a predictor of clinical outcome in patients undergoing spinal fusion. The intent of this study was to examine the influence of workers compensation status on the chronological outcome of patients undergoing anterior lumbar interbody fusion (ALIF) with intervertebral fusion cages.Methods used: Patients with symptomatic lumbar disc disease were enrolled in prospective studies to

Harvinder Sandhu; Thomas Zdeblick; Kevin Foley; Fengyu Zheng; Safdar Khan

2002-01-01

4

Radiographic Results of Minimally Invasive (MIS) Lumbar Interbody Fusion (LIF) Compared with Conventional Lumbar Interbody Fusion  

PubMed Central

Objective To evaluate the radiographic results of minimally invasive (MIS) anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF). Methods Twelve and nineteen patients who underwent MIS-ALIF, MIS-TLIF, respectively, from 2006 to 2008 were analyzed with a minimum 24-months' follow-up. Additionally, 18 patients treated with single level open TLIF surgery in 2007 were evaluated as a comparative group. X-rays and CT images were evaluated preoperatively, postoperatively, and at the final follow-up. Fusion and subsidence rates were determined, and radiographic parameters, including lumbar lordosis angle (LLA), fused segment angle (FSA), sacral slope angle (SSA), disc height (DH), and foraminal height (FH), were analyzed. These parameters were also compared between the open and MIS-TLIF groups. Results In the MIS interbody fusion group, statistically significant increases were observed in LLA, FSA, and DH and FH between preoperative and final values. The changes in LLA, FSA, and DH were significantly increased in the MIS-ALIF group compared with the MIS-TLIF group, but SSA and FH were not significantly different. No significant differences were seen between open and MIS-TLIF except for DH. The interbody subsidence and fusion rates of the MIS groups were 12.0±4% and 96%, respectively. Conclusion Radiographic results of MIS interbody fusion surgery are as favorable as those with conventional surgery regarding fusion, restoration of disc height, foraminal height, and lumbar lordosis. MIS-ALIF is more effective than MIS-TLIF for intervertebral disc height restoration and lumbar lordosis.

Lim, Jae Kwan

2013-01-01

5

Current status of bone graft options for anterior interbody fusion of the cervical and lumbar spine.  

PubMed

Anterior cervical discectomy and fusion (ACDF) and anterior lumbar interbody fusion (ALIF) are common surgical procedures for degenerative disc disease of the cervical and lumbar spine. Over the years, many bone graft options have been developed and investigated aimed at complimenting or substituting autograft bone, the traditional fusion substrate. Here, we summarise the historical context, biological basis and current best evidence for these bone graft options in ACDF and ALIF. PMID:23743981

Chau, Anthony Minh Tien; Xu, Lileane Liang; Wong, Johnny Ho-Yin; Mobbs, Ralph Jasper

2014-01-01

6

Post-discectomy syndrome treated with lumbar interbody fusion  

PubMed Central

We studied 27 patients with post-discectomy syndrome. All patients had Lumbar Interbody Fusion with titanium cages and pedicle screw fixation either as Anterior (ALIF, n=18) or as Transforaminal Lumbar Interbody Fusion (TLIF, n=9). Follow-up ranged from 24 to 94 months. The clinical and radiological data were compared. The outcome was evaluated using the Oswestry low back pain disability score and the visual analogue pain intensity scale. Outcomes were similar for all patients regardless of surgical technique and showed a significant improvement at final follow-up.

Halm, Henry; Hackenberg, Lars; Liljenqvist, Ulf; Bovingloh, Albert Schulze

2006-01-01

7

CT navigated lateral interbody fusion.  

PubMed

Lateral interbody fusion techniques are heavily reliant on fluoroscopy for retractor docking and graft placement, which expose both the patient and surgeon to high doses of radiation. Use of image-guided technologies with CT-based images, however, can eliminate this radiation exposure for the surgeon. We describe the surgical technique of performing lateral lumbar interbody fusion using CT navigation. PMID:23931938

Drazin, Doniel; Liu, John C; Acosta, Frank L

2013-10-01

8

Transforaminal versus Anterior Lumbar Interbody Fusion in Long Deformity Constructs: a matched cohort analysis.  

PubMed

ABSTRACT: Study Design. Prospectively-enrolled, retrospectively analyzed matched cohort analysis.Objective. Evaluate the relative merits of transforaminal lumbar interbody fusion (TLIF) and anterior lumbar interbody fusion (ALIF) when used in long deformity constructs.Summary of Background Data. Interbody fusion is frequently employed at the caudal levels of long-segment spinal deformity instrumentation constructs in order to protect the sacral implants and enhance fusion rates. However, there is a paucity of literature regarding which technique is more efficacious.Methods. 42 TLIF and 42 ALIF patients were matched with respect to age, gender, comorbidities, curve magnitude, fusion length, and ALIF/TLIF level. Radiographs and clinical outcomes were compared at minimum 2-year follow-up.Results. Age averaged 54.0 years and instrumented vertebrae averaged 13.6. TLIFs had less operative time (481 vs. 595 minutes, P = 0.0007), but greater blood loss (2011 vs. 1281 mL, P = 0.0002). Overall complications (TLIF 12/42 vs. ALIF 15/42) and neurologic complications (TLIF 4/42 vs. ALIF 3/42) did not differ. One pseudarthrosis occurred at an ALIF level, with none at TLIF levels. ALIF patients began with lower SRS scores but improved more (44.4 to 70.7 vs. 58.6 to 70.6, P = 0.0043). ODI scores in both groups improved similarly. Regionally, ALIFs engendered more lordosis than TLIFs at L3-S1 (gain of 6.9° vs. -2.6°, P<0.0001) but not T12-S1 (gain of 11.5° vs. 7.9°, P = 0.29). Locally, ALIFs created more lordosis at L4-5 (gain of 5.6° vs. -1.7°, P<0.0001) and L5-S1 (gain of 2.5° vs. -1.4°, P = 0.022), but not at L3-4 (gain of 5.3° vs. 4.0°, P = 0.65). TLIF patients obtained greater correction of AP Cobb angles in lumbar (reduction of 22.4° vs. 9.9°, P<0.0001) and fractional lumbosacral curves (reduction of 10.3° vs. 3.4°, P<0.0001).Conclusion. Spinal deformity surgery utilizing TLIFs rather than ALIFs resulted in shorter operative time with no difference in complication rates. ALIFs provided more segmental lordosis, while TLIFs afforded better correction of scoliotic curves. PMID:23442780

Dorward, Ian G; Lenke, Lawrence G; Bridwell, Keith H; O?leary, Patrick T; Stoker, Geoffrey E; Pahys, Joshua M; Kang, Matthew M; Sides, Brenda A; Koester, Linda A

2013-02-25

9

Bone graft substitutes for anterior lumbar interbody fusion.  

PubMed

The procedure of anterior lumbar interbody fusion (ALIF) is commonly performed on patients suffering from pain and/or neurological symptoms associated with disorders of the lumbar spine caused by disc degeneration and trauma. Surgery is indicated when prolonged conservative management proves ineffective. Because an important objective of the ALIF procedure is solid arthrodesis of the degenerative spinal segment, bone graft selection is critical. Iliac crest bone grafts (ICBG) remain the "gold standard" for achieving lumbar fusion. However, patient dissatisfaction stemming from donor site morbidity, lengthier operating times and finite supply of ICBG has prompted a search for better alternatives. Here presented is a literature review evaluating available bone graft options assessed within the clinical setting. These options include autografts, allograft-based, synthetic and cell-based technologies. The emphasis is on the contentious use of recombinant human bone morphogenetic proteins, which is in widespread use and has demonstrated both significant osteogenic potential and risk of complications. PMID:23658041

Mobbs, Ralph J; Chung, Mina; Rao, Prashanth J

2013-05-01

10

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 11: Interbody techniques for lumbar fusion.  

PubMed

Interbody fusion techniques have been promoted as an adjunct to lumbar fusion procedures in an effort to enhance fusion rates and potentially improve clinical outcome. The medical evidence continues to suggest that interbody techniques are associated with higher fusion rates compared with posterolateral lumbar fusion (PLF) in patients with degenerative spondylolisthesis who demonstrate preoperative instability. There is no conclusive evidence demonstrating improved clinical or radiographic outcomes based on the different interbody fusion techniques. The addition of a PLF when posterior or anterior interbody lumbar fusion is performed remains an option, although due to increased cost and complications, it is not recommended. No substantial clinical benefit has been demonstrated when a PLF is included with an interbody fusion. For lumbar degenerative disc disease without instability, there is moderate evidence that the standalone anterior lumbar interbody fusion (ALIF) has better clinical outcomes than the ALIF plus instrumented, open PLF. With regard to type of interbody spacer used, frozen allograft is associated with lower pseudarthrosis rates compared with freeze-dried allograft; however, this was not associated with a difference in clinical outcome. PMID:24980588

Mummaneni, Praveen V; Dhall, Sanjay S; Eck, Jason C; Groff, Michael W; Ghogawala, Zoher; Watters, William C; Dailey, Andrew T; Resnick, Daniel K; Choudhri, Tanvir F; Sharan, Alok; Wang, Jeffrey C; Kaiser, Michael G

2014-07-01

11

A Radiological Comparison of Anterior Fusion Rates in Anterior Lumbar Interbody Fusion  

PubMed Central

Aim?To compare anterior fusion in standalone anterior lumbar interbody fusion (ALIF) using cage and screw constructs and anterior cage–alone constructs with posterior pedicle screw supplementation but without posterior fusion. Methods?Eighty-five patients underwent single- or two-level ALIF procedure for degenerative disk disease or lytic spondylolisthesis (SPL). Posterior instrumentation was performed without posterior fusion in all cases of lytic SPL and when the anterior cage used did not have anterior screw through cage fixation. Results?Seventy (82%) patients had adequate radiological follow-up at a mean of 19 months. Forty patients had anterior surgery alone (24 single level and 16 two levels) and 30 had front-back surgery (15 single level and 15 two levels). Anterior locked pseudarthrosis was only seen in the anterior surgery–alone group when using the STALIF cage (Surgicraft, Worcestershire, UK) (37 patients). This occurred in five of the single-level surgeries (5/22) and nine of the two-level surgeries (9/15). Fusion was achieved in 100% of the front-back group and only 65% (26/40) of the anterior surgery–alone group. Conclusion?Posterior pedicle screw supplementation without posterolateral fusion improves the fusion rate of ALIF when using anterior cage and screw constructs. We would recommend supplementary posterior fixation especially in cases where more than one level is being operated.

McCarthy, M. J. H.; Ng, L.; Vermeersch, G.; Chan, D.

2012-01-01

12

Biomechanical comparison of anterior lumbar interbody fusion: stand-alone interbody cage versus interbody cage with pedicle screw fixation - a finite element analysis  

PubMed Central

Background Anterior lumbar interbody fusion (ALIF) followed by pedicle screw fixation (PSF) is used to restore the height of the intervertebral disc and provide stability. Recently, stand-alone interbody cage with anterior fixation has been introduced, which eliminates the need for posterior surgery. We compared the biomechanics of the stand-alone interbody cage to that of the interbody cage with additional PSF in ALIF. Methods A three-dimensional, non-linear finite element model (FEM) of the L2-5 segment was modified to simulate ALIF in L3-4. The models were tested under the following conditions: (1) intact spine, (2) destabilized spine, (3) with the interbody cage alone (type 1), (4) with the stand-alone cage with anterior fixation (SynFix-LR®; type 2), and (5) with type 1 in addition to PSF (type 3). Range of motion (ROM) and the stiffness of the operated level, ROM of the adjacent segments, load sharing distribution, facet load, and vertebral body stress were quantified with external loading. Results The implanted models had decreased ROM and increased stiffness compared to those of the destabilized spine. The type 2 had differences in ROM limitation of 8%, 10%, 4%, and 6% in flexion, extension, axial rotation, and lateral bending, respectively, compared to those of type 3. Type 2 had decreased ROM of the upper and lower adjacent segments by 3-11% and 3-6%, respectively, compared to those of type 3. The greatest reduction in facet load at the operated level was observed in type 3 (71%), followed by type 2 (31%) and type 1 (23%). An increase in facet load at the adjacent level was highest in type 3, followed by type 2 and type 1. The distribution of load sharing in type 2 (anterior:posterior, 95:5) was similar to that of the intact spine (89:11), while type 3 migrated posterior (75:25) to the normal. Type 2 reduced about 15% of the stress on the lower vertebral endplate compared to that in type 1. The stress of type 2 increased two-fold compared to the stress of type 3, especially in extension. Conclusions The stand-alone interbody cage can provide sufficient stability, reduce stress in adjacent levels, and share the loading distribution in a manner similar to an intact spine.

2013-01-01

13

Fracture of the L-4 vertebral body after use of a stand-alone interbody fusion device in degenerative spondylolisthesis for anterior L3-4 fixation.  

PubMed

Many studies attest to the excellent results achieved using anterior lumbar interbody fusion (ALIF) for degenerative spondylolisthesis. The purpose of this report is to document a rare instance of L-4 vertebral body fracture following use of a stand-alone interbody fusion device for L3-4 ALIF. The patient, a 55-year-old man, had suffered intractable pain of the back, right buttock, and left leg for several weeks. Initial radiographs showed Grade I degenerative spondylolisthesis, with instability in the sagittal plane (upon 15° rotation) and stenosis of central and both lateral recesses at the L3-4 level. Anterior lumbar interbody fusion of the affected vertebrae was subsequently conducted using a stand-alone cage/plate system. Postoperatively, the severity of spondylolisthesis diminished, with resolution of symptoms. However, the patient returned 2 months later with both leg weakness and back pain. Plain radiographs and CT indicated device failure due to anterior fracture of the L-4 vertebral body, and the spondylolisthesis had recurred. At this point, bilateral facetectomies were performed, with reduction/fixation of L3-4 by pedicle screws. Again, degenerative spondylolisthesis improved postsurgically and symptoms eased, with eventual healing of the vertebral body fracture. This report documents a rare instance of L-4 vertebral body fracture following use of a stand-alone device for ALIF at L3-4, likely as a consequence of angular instability in degenerative spondylolisthesis. Under such conditions, additional pedicle screw fixation is advised. PMID:24725181

Kwon, Yoon-Kwang; Jang, Ju-Hee; Lee, Choon-Dae; Lee, Sang-Ho

2014-06-01

14

Comparison of low back fusion techniques: transforaminal lumbar interbody fusion (TLIF) or posterior lumbar interbody fusion (PLIF) approaches  

Microsoft Academic Search

The authors review and compare posterior lumbar interbody fusion (PLIF) with transforaminal lumbar interbody fusion (TLIF).\\u000a A review of the literature is performed wherein the history, indications for surgery, surgical procedures with their respective\\u000a biomechanical advantages, potential complications, and grafting substances are presented. Along with the technical advancements\\u000a and improvements in grafting substances, the indications and use of PLIF and

Chad D. Cole; Todd D. McCall; Meic H. Schmidt; Andrew T. Dailey

2009-01-01

15

Analysis of spinal lumbar interbody fusion cage subsidence using Taguchi method, finite element analysis, and artificial neural network  

NASA Astrophysics Data System (ADS)

Subsidence, when implant penetration induces failure of the vertebral body, occurs commonly after spinal reconstruction. Anterior lumbar interbody fusion (ALIF) cages may subside into the vertebral body and lead to kyphotic deformity. No previous studies have utilized an artificial neural network (ANN) for the design of a spinal interbody fusion cage. In this study, the neural network was applied after initiation from a Taguchi L 18 orthogonal design array. Three-dimensional finite element analysis (FEA) was performed to address the resistance to subsidence based on the design changes of the material and cage contact region, including design of the ridges and size of the graft area. The calculated subsidence is derived from the ANN objective function which is defined as the resulting maximum von Mises stress (VMS) on the surface of a simulated bone body after axial compressive loading. The ANN was found to have minimized the bone surface VMS, thereby optimizing the ALIF cage given the design space. Therefore, the Taguchi-FEA-ANN approach can serve as an effective procedure for designing a spinal fusion cage and improving the biomechanical properties.

Nassau, Christopher John; Litofsky, N. Scott; Lin, Yuyi

2012-09-01

16

Surgical management of minimally invasive anterior lumbar interbody fusion with stand-alone interbody cage for L4-5 degenerative disorders: clinical and radiographic findings.  

PubMed

Surgical treatment for degenerative spinal disorders is controversial, although lumbar fusion is considered an acceptable option for disabling lower back pain. Patients underwent instrumented minimally invasive anterior lumbar interbody fusion (mini-ALIF) using a retroperitoneal approach except for requiring multilevel fusions, severe spinal canal stenosis, high-grade spondylolisthesis, and a adjacent segments disorders. We retrospectively reviewed the clinical records and radiographs of 142 patients who received mini-ALIF for L4-5 degenerative lumbar disorders between 1998 and 2010. We compared preoperative and postoperative clinical data and radiographic measurements, including the modified Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score for back and leg pain, disc height (DH), whole lumbar lordosis (WL), and vertebral wedge angle (WA). The mean follow-up period was 76 months. The solid fusion rate was 90.1% (128/142 patients). The average length of hospital stay was 6.9 days (range, 3-21 days). The mean blood loss was 63.7 ml (range, 10-456 ml). The mean operation time was 155.5 min (range, 96-280 min). The postoperative JOA and VAS scores for back and leg pain were improved compared with the preoperative scores. Radiological analysis showed significant postoperative improvements in DH, WL, and WA, and the functional and radiographical outcomes improved significantly after 2 years. The 2.8% complication rate included cases of wound infection, liquorrhea, vertebral body fractures, and a misplaced cage that required revision. Mini-ALIF was found to be associated with improved clinical results and radiographic findings for L4-5 disorders. A retroperitoneal approach might therefore be a valuable treatment option. PMID:24140782

Hironaka, Yasuo; Morimoto, Tetsuya; Motoyama, Yasushi; Park, Young-Su; Nakase, Hiroyuki

2013-01-01

17

Cervical disc prosthesis replacement and interbody fusion: a comparative study.  

PubMed

The purpose of this paper is to compare the new functional intervertebral cervical disc prosthesis replacement and the classical interbody fusion operation, including the clinical effect and maintenance of the stability and segmental motion of cervical vertebrae. Twenty-four patients with single C5-6 intervertebral disk hernias were specifically selected and divided randomly into two groups: One group underwent artificial cervical disc replacement and the other group received interbody fusion. All patients were followed up and evaluated. The operation time for the single disc replacement was (130 +/- 50) minutes and interbody fusion was (105 +/- 53) minutes. Neurological or vascular complications were not observed during or after operation. There was no prosthesis subsidence or extrusion. The JOA score of the group with prosthesis replacement increased from an average of 8.6 to 15.8. The JOA score of the group with interbody fusion increased from an average of 9 to 16.2. The clinical effect and the ROM of the adjacent space of the two groups showed no statistical difference. The short follow-up time does not support the advantage of the cervical disc prosthesis. The clinical effect and the maintenance of the function of the motion of the intervertebral space are no better than the interbody fusion. At least 5 years of follow-up is needed to assess the long-term functionality of the prosthesis and the influence on adjacent levels. PMID:17180356

Peng-Fei, Sun; Yu-Hua, Jia

2008-02-01

18

[Axial lumbar Interbody Fusion: Prospective Monocentric Study].  

PubMed

PURPOSE OF THE STUDY The aim of this prospective study was to evaluate clinical and radiographic results in the patients who underwent L5-S1 fixation using the technique of percutaneous lumbar interbody fusion (AxiaLIF). MATERIAL The study comprised 23 patients, 11 women and 12 men, who ranged from age of 21 to 63 years, with an average of 48.2 years. In all patients surgical posterior stabilisation involving the L5-S1 segment had previously been done. The initial indications for surgery were L5-S1 spondylolisthesis in 20 and L5-S1 spondylosis and stenosis in three patients. METHODS The AxiaLIF technique for L5-S1 fixation was indicated in overweight patients and in those after repeated abdominal or retroperitoneal surgery. A suitable position and shape of the sacrum or lumbosacral junction was another criterion. The patients were evaluated between 26 and 56 months (average, 40.4 months) after primary surgery and, on the basis of CT and radiographic findings, bone union and lumbosacral junction stability were assessed. The clinical outcome was investigated using the ODI and VAS systems and the results were statistically analysed by the Wilcoxon test for paired samples with statistical significance set at a level of 0.05. RESULTS The average VAS value was 6.6 before surgery and, after surgery, 5.2 at three months, 4.2 at six months, 3.1 at one year, 2.9 at two years and 2.1 at three years (n=18). At two post-operative years, improvement in the VAS value by 56.1% was recorded. The average pre-operative ODI value was 25.1; the post-operative values were 17.0 at six months, 12.3 at one year, 10.6 at two years and 8.2 at three years (n=18). At two years after surgery the ODI value improved by 57.8%. To the question concerning their willingness to undergo, with acquired experience, surgery for the same diagnosis, 21 patients (91.3%) gave an affirmative answer. Neither screw breakage nor neurovascular damage or rectal injury was found. CT scans showed complete interbody bone fusion in 22 of the 23 patients (95.6%), In one patient the finding was not clear. Also, posterolateral fusion was achieved in all but one patients (95.6%). A stable L5-S1 segment was found in all patients at all follow-up intervals. The improvement in both VAS and ODI values was statistically significant. DISCUSSION In addition to indications usual in degenerative disc disease, overweight patients, those who had repeated trans- or retroperitoneal surgery in the L5-S1 region or who underwent long posterior fixation to stabilise the caudal margin of instrumentation are indicated for the AxiaLIF procedure. The clinical results of our study are in agreement with the conclusions of other studies and are similar to the outcomes of surgery using other types of fusion or dynamic stabilisation for this diagnosis. The high rate of fusion in our group is affected by use of a rigid transpedicular fixator together with posterolateral arthrodesis. On the other hand, no negative effects of only synthetic bone applied to interbody space were recorded. CONCLUSIONS The percutaneous axial pre-sacral approach to the L5-S1 interbody space with application of a double-treaded screw is another option for the management of this much strained segment. The technique is useful particularly when contraindications for conventional surgical procedures are present in patients with anatomical anomalies, in overweight patients or in those who have had repeated surgery in the region. Clinical outcomes and the success rate for L5-S1 bone fusion are comparable with conventional techniques. Complications are rare but their treatment is difficult. Key words:AxiaLIF, lumbar spine, spinal fusion, axial lumbar fixation. PMID:24945389

Stulík, J; Adámek, S; Barna, M; Kasp?íková, N; Polanecký, O; Kryl, J

2014-01-01

19

Extension CT scan: its suitability for assessing fusion after posterior lumbar interbody fusion  

Microsoft Academic Search

Posterior lumbar interbody fusion (PLIF) is a popular procedure for treating lumbar canal stenosis with spinal instability,\\u000a and several reports concerning fusion assessment methods exist. However, there are currently no definitive criteria for diagnosing\\u000a a successful interbody fusion in the lumbar spine. We suggested evaluating fusion status using computed tomography (CT) in\\u000a extension position to detect pseudoarthrosis more precisely. The

Hiroaki NakashimaYasutsugu; Yasutsugu Yukawa; Keigo Ito; Yumiko Horie; Masaaki Machino; Shunsuke Kanbara; Daigo Morita; Shiro Imagama; Naoki Ishiguro; Fumihiko Kato

20

Double-segment Wilhelm Tell technique for anterior lumbar interbody fusion in unstable isthmic spondylolisthesis and adjacent segment discopathy.  

PubMed

The Wilhelm Tell technique is a novel instrumented anterior lumbar interbody fusion (ALIF) procedure using a specially designed composite carbon fibre cage and a single short-threaded cancellous screw that obliquely passes through the upper adjacent vertebral body, the interbody cage itself and through the lower adjacent vertebral body. This single-stage fusion method, which is in principle a combination of the Louis technique and modern cage surgery, is reported to have a lower rate of pseudoarthrosis formation than stand-alone cage techniques. In addition, it eliminates both the surgical trauma of paravertebral muscle retraction and the risk of neural damage by poorly located pedicular screws. This anterior approach allows decompression of neural structures within the anterior part of the spinal canal and the foraminal region. It is the purpose of this case report, to present the successful application of this novel technique in a 32-year-old woman who concurrently suffered from severe instability-related back pain from L4/5 isthmic spondylolisthesis and marked L5/S1 degenerative disc disease. PMID:16459090

Wenger, Markus; Vogt, Emanuel; Markwalder, Thomas-Marc

2006-02-01

21

Biomechanical comparison of two different concepts for stand alone anterior lumbar interbody fusion  

PubMed Central

Segmental instability in degenerative disc disease is often treated with anterior lumbar interbody fusion (ALIF). Current techniques require an additional posterior approach to achieve sufficient stability. The test device is an implant which consists of a PEEK-body and an integrated anterior titanium plate hosting four diverging locking screws. The test device avoids posterior fixation by enhancing stability via the locking screws. The test device was compared to an already established stand alone interbody implant in a human cadaveric three-dimensional stiffness test. In the biomechanical test, the L4/5 motion segment of 16 human cadaveric lumbar spines were isolated and divided into two test groups. Tests were performed in flexion, extension, right and left lateral bending, right and left axial rotation. Each specimen was tested in native state first, then a discectomy was performed and either of the test implants was applied. Finite element analysis (FE) was also performed to investigate load and stress distribution within the implant in several loading conditions. The FE models simulated two load cases. These were flexion and extension with a moment of 5 Nm. The biomechanical testing revealed a greater stiffness in lateral bending for the SynFix-LR™ compared to the established implant. Both implants showed a significantly higher stiffness in all loading directions compared to the native segment. In flexion loading, the PEEK component takes on most of the load, whereas the majority of the extension load is put on the screws and the screw–plate junction. Clinical investigation of the test device seems reasonable based on the good results reported here.

Gerlach, R.; Schar, B.; Cain, C. M. J.; Achatz, W.; Pflugmacher, R.; Haas, N. P.; Kandziora, F.

2008-01-01

22

The axial transsacral approach to interbody fusion at L5-S1.  

PubMed

Lumbosacral interbody fusion may be indicated to treat degenerative disc disease at L5-S1, instability or spondylolisthesis at that level, and severe neural foraminal stenosis resulting from loss of disc space height. In addition, L5-S1 interbody fusion may provide anterior support to a long posterior fusion construct and help offset the stresses experienced by the distal-most screws. There are 3 well-established techniques for L5-S1 interbody fusion: anterior lumbar interbody fusion, posterior lumbar interbody fusion, and transforaminal lumbar interbody fusion. Each of these has advantages and pitfalls. A more recently described axial transsacral technique, utilizing the presacral corridor, may represent a minimally invasive approach to obtaining lumbosacral interbody arthrodesis. Biomechanical studies demonstrate that the stiffness of the axial rod is comparable to existing fixation devices, suggesting that, biomechanically, it may be a good implant for obtaining lumbosacral interbody fusion. Clinical studies have demonstrated good early results with the use of the axial transsacral approach in obtaining lumbosacral interbody fusion for degenerative disc disease, spondylolisthesis, and below long posterior fusion constructs. The technique is exacting and complications can be major, including rectal perforation and fistula, loss of correction, and pseudarthrosis. PMID:24785490

Issack, Paul S; Kotwal, Suhel Y; Boachie-Adjei, Oheneba

2014-05-01

23

Minimum 10-Year Follow-up Study of Anterior Lumbar Interbody Fusion for Degenerative Spondylolisthesis: Progressive Pattern of the Adjacent Disc Degeneration  

PubMed Central

Study Design Retrospective study. Purpose The aims of the current study are to evaluate the minimum 10-year follow-up clinical results of anterior lumbar interbody fusion (ALIF) for degenerative spondylolisthesis. Overview of Literature ALIF has been widely used as a treatment regimen in the management of lumbar spondylolisthesis. Still much controversy exists regarding the factors that affect the postoperative clinical outcomes. Methods The author performed a retrospective review of 20 patients with degenerative spondylolisthesis treated with ALIF (follow-up, 16.4 years). The clinical results were assessed by the Japanese Orthopaedic Association (JOA) score for low back pain, vertebral slip and disc height index on the radiographs. Results The mean preoperative JOA score was 7.1 ± 1.8 points (15-point-method). At 1 year, 5 years, and 10 years or more after surgery, the JOA scores were assessed as 12.4 ± 2.2 points, 12.7 ± 2.6 points, 12.0 ± 2.5 points, respectively (excluding the data of reoperated cases). The adjacent disc degeneration developed in all cases during the long-term follow-up. The progressive pattern of disc degeneration was divided into three types. Initially, disc degeneration occurred due to disc space narrowing. After that, the intervertebral discs showed segmental instability with translation at the upper level. But the lower discs showed osteophyte formation, and occasionally lead to the collapse or spontaneous union. Conclusions The clinical results of the long-term follow-up data after ALIF became worse due to the adjacent disc degeneration. The progressive pattern of disc degeneration was different according to the adjacent levels.

Yasuda, Taketoshi; Hori, Takeshi; Suzuki, Kayo; Kawaguchi, Yoshiharu

2012-01-01

24

Lateral transpsoas lumbar interbody fusion: outcomes and deformity correction.  

PubMed

The lateral transpsoas approach for interbody fusion is a minimally invasive technique that has been gaining increasing popularity in the management of a variety of spinal degenerative disorders. Recently, there has been increasing utilization of this technique in the management of adult deformity. The authors present a review of the current evidence of using the lateral lumbar transpsoas approach in the correction of adult degenerative scoliosis. PMID:24703453

Dahdaleh, Nader S; Smith, Zachary A; Snyder, Laura A; Graham, Randall B; Fessler, Richard G; Koski, Tyler R

2014-04-01

25

Clinical and radiological relationship between posterior lumbar interbody fusion and posterolateral lumbar fusion  

Microsoft Academic Search

BackgroundPosterolateral lumbar fusion (PLF) is the most popular technique for stabilizing the lumbar spine. Biomechanically, PLF decreases segmental motion in the posterior column, which presumably reduces facet joint pain. Posterior lumbar interbody fusion (PLIF) may decompress nerve roots by distracting the collapsed disc space, and achieving optimal fusion in relation to load-bearing capacity. The purpose of the study was to

Zvi Lidar; Andrew Beaumont; Jason Lifshutz; Dennis J. Maiman

2005-01-01

26

The Wilhelm tell technique for anterior lumbar interbody fusion. Technical note.  

PubMed

Experience indicates that stand-alone cages may lack the necessary stability to secure highly unstable motion segments at the lumbosacral junction. The authors have designed a special carbon fiber composite interbody cage that allows additional screw placement in anterior lumbar interbody fusion procedures performed at the lumbosacral junction. PMID:12650410

Markwalder, Thomas-Marc; Wenger, Markus; Elsig, Jean-Pierre; Laloux, Etienne

2003-03-01

27

Minimally invasive lateral lumbar interbody fusion with direct psoas visualization  

PubMed Central

Background Minimally invasive lateral approaches to the lumbar spine have been adopted to allow access to the intervertebral disc space while avoiding the complications associated with anterior or posterior approaches. This report describes a minimally invasive technique for lateral lumbar interbody fusion LLIF that allows direct intraoperative visualization of the psoas and surrounding neurovasculature (DV-LIF). Methods The technique utilizes a radiolucent tubular retractor and a secondary psoas retractor that allows a muscle-sparing approach while offering excellent visualization of the operative site. The unique advantage of this procedure is that the psoas muscle and surrounding nerves can be directly visualized intraoperatively to supplement neuromonitoring. We retrospectively reviewed complication rates in 34 patients treated with DV-LLIF (n?=?19) or standard lateral lumbar interbody fusion (S-LLIF, n?=?15). Results There were 29 complications (median: 1 per patient) with DV-LLIF and 20 (median: 1 per patient) complications with S-LLIF. Postoperative sensory deficits were reported in eight (42%) and seven (47%) patients, respectively. Thigh pain or numbness was reported in eight (42%) and five (33%) patients, respectively. The percentage of the overall complications directly attributable to the procedure was 69% with DV-LLIF and 83% with S-LLIF. One severe complication (back pain) was reported in one DV-LLIF patient and four severe complications (severe bleeding, respiratory failure, deep venous thrombosis and gastrointestinal prophylaxis, and nicked renal vein and aborted procedure) were reported in two S-LLIF patients. Conclusions Preliminary evidence suggests that minimally invasive lateral interbody fusion with direct psoas visualization may reduce the risk for severe procedural complications.

2014-01-01

28

Posterior lumbar interbody fusion and segmental lumbar lordosis  

Microsoft Academic Search

Introduction  The sagittal plane of body produces a convex curve anteriorly referred to as the lordotic curve. Malalignment of lordotic\\u000a curve leads to low back disorders and lumbar spinal surgery has been known to cause this. This study was a retrospective analysis\\u000a of the effects of posterior lumbar interbody fusion using cages on segmental lumbar lordosis.\\u000a \\u000a \\u000a \\u000a Materials and methods  We conducted a

Rahul Kakkar; P. B. R. Sirigiri; A. Howieson; A. Siva Raman; R. J. Crawford

2007-01-01

29

Bilateral implantation of low-profile interbody fusion cages: subsidence, lordosis, and fusion analysis  

Microsoft Academic Search

BACKGROUND CONTEXT: The use of interbody fusion cages as a treatment for degenerative disc disease has become widespread. Low-profile cages have been developed to allow a closer fit when implanting bilateral cages in patients with smaller vertebral bodies. Some surgeons feel the open design also allows better bone contact and visualization. This is particularly true when two low-profile cages are

Michael Schiffman; Salvador A Brau; Robin Henderson; Gwen Gimmestad

2003-01-01

30

Posterior lumbar interbody fusion using one diagonal fusion cage with transpedicular screw\\/rod fixation  

Microsoft Academic Search

Posterior lumbar interbody fusion (PLIF) using threaded cages has gained wide popularity for lumbosacral spinal disease. Our biomechanical tests showed that PLIF using a single diagonal cage with unilateral facetectomy does add a little to spinal stability and provides equal or even higher postoperative stability than PLIF using two posterior cages with bilateral facetectomy. Studies also demonstrated that cages placed

Jie Zhao; Tiesheng Hou; Xinwei Wang; Shengzhong Ma

2003-01-01

31

Direct lateral interbody fusion (DLIF) at the lumbosacral junction L5-S1.  

PubMed

The direct lateral interbody fusion (DLIF), a minimally invasive lateral approach for placement of an interbody fusion device, does not require nerve root retraction or any contact with the great vessels and can lead to short operative times with little blood loss. Due to anatomical restrictions, this procedure has not been used at the lumbosacral (L5-S1) junction. Lumbosacral transitional vertebrae (LSTV), a structural anomaly of the lumbosacral spine associated with low back pain, can result in a level being wrongly identified pre-operatively due to misnumbering of the vertebral levels. To our knowledge, use of the DLIF graft in this patient is the first report of an interbody fusion graft being placed at the disc space between the LSTV and S1 via the transpsoas route. We present a review of the literature regarding the LSTV variation as well as the lateral placement of interbody fusion grafts at the lumbosacral junction. PMID:22551586

Shirzadi, Ali; Birch, Kurtis; Drazin, Doniel; Liu, John C; Acosta, Frank

2012-07-01

32

Biological performance of a polycaprolactone-based scaffold used as fusion cage device in a large animal model of spinal reconstructive surgery  

Microsoft Academic Search

A bioactive and bioresorbable scaffold fabricated from medical grade poly (epsilon-caprolactone) and incorporating 20% beta-tricalcium phosphate (mPCL–TCP) was recently developed for bone regeneration at load bearing sites. In the present study, we aimed to evaluate bone ingrowth into mPCL–TCP in a large animal model of lumbar interbody fusion. Six pigs underwent a 2-level (L3\\/4; L5\\/6) anterior lumbar interbody fusion (ALIF)

Sunny A. Abbah; Christopher X. L. Lam; Dietmar W. Hutmacher; James C. H. Goh; Hee-Kit Wong

2009-01-01

33

Outcome of instrumented lumbar fusion for low grade spondylolisthesis; Evaluation of interbody fusion with & without cages  

PubMed Central

Object: The aim is to evalute the outcome of posterior lumbar interbody fusion with autologous bone graft versus titanium Cages, BAK system (Bagby – Kuslich, Spine Tech, Inc. Minneapolis, MN) for low grade spondyloisthesis (Grade1,11). Interbody cages have been developed to replace tricortical Interbody grafts in posterior lumbar interbody fusion (PLIF) procedures. The cages provide immediate post operative stability and facilitate bony union with cancellous bone packed in the cage itself. METHOD: We Evaluated 50 consecutive patients in whom surgery was performed between June 2000 to June 2003 in the Main Alexandria University Hospital at EGYPT. Twenty five patients were operated using autologous bone graft and 25 patients using the BAK cages. The neuro–radiologic al work up consisted of; plain X – ray lumbosacral spine including dynamic films preoperative and postoperative follow up; C.T lumbosacral spine and MRI lumbosacral spine. The surgery was performed at L4-5 level in 34 cases and at L5-S1 level in 16 cases. The median follow up was 15 months. RESULTS: Satisfactory fusion was obtained at all levels at a minimum one year follow – up. The fusion rate was 96% (24 patients) for the cage group and 80% (20 patients) for bone graft group however clinical improvement was 64% (16 patients) for those with bone graft group. CONCLUSION: A higher fusion rates and a better clinical outcome have been obtained by Instrumented PLIF with titanium cages that with bone graft. Inderbody fusion cages help to stabilize spainal segment primarily by distracting them as well as by allowing bone ingrowth and fusion. The procedure is safe and effective with 96% fusion rate and 76% overall Satisfactory rate. The use of cages help to distract the space between the vertebral bodies making the correction of the degree of spondylolisthesis easier. Long term follow up revealed better fusion rate and better realignment and less resorption with cages than with bone grafts.

Fathy, Mostafa; Fahmy, Mohamed; Fakhri, Mazen; Aref, Khaled; Abdin, Khaled; Zidan, Ihab

2010-01-01

34

Comparison of the early results of transforaminal lumbar interbody fusion and posterior lumbar interbody fusion in symptomatic lumbar instability  

PubMed Central

Background: Transforaminal lumbar interbody fusion (TLIF) has been preferred to posterior lumbar interbody fusion (PLIF) for different spinal disorders but there had been no study comparing their outcome in lumbar instability. A comparative retrospective analysis of the early results of TLIF and PLIF in symptomatic lumbar instability was conducted between 2005 and 2011. Materials and Methods: Review of the records of 102 operated cases of lumbar instability with minimum 1 year followup was done. A total of 52 cases (11 men and 41 women, mean age 46 years SD 05.88, range 40-59 years) underwent PLIF and 50 cases (14 men and 36 women, mean age 49 years SD 06.88, range 40-59 years) underwent TLIF. The surgical time, duration of hospital stay, intraoperative blood loss were compared. Self-evaluated low back pain and leg pain status (using Visual Analog Score), disability outcome (using Oswestry disability questionnaire) was analyzed. Radiological structural restoration (e.g., disc height, foraminal height, lordotic angle, and slip reduction), stability (using Posner criteria), fusion (using Hackenberg criteria), and overall functional outcome (using MacNab's criteria) were compared. Results: Pain, disability, neurology, and overall functional status were significantly improved in both groups but PLIF required more operative time and caused more blood loss. Postoperative hospital stay, structural restoration, stability, and fusion had no significant difference but neural complications were relatively more with PLIF. Conclusions: Both methods were effective in relieving symptoms, achieving structural restoration, stability, and fusion, but TLIF had been associated with shorter operative time, less blood loss, and lesser complication rates for which it can be preferred for symptomatic lumbar instability.

Sakeb, Najmus; Ahsan, Kamrul

2013-01-01

35

Transforaminal lumbar interbody fusion and posterior lumbar interbody fusion utilizing BMP-2 in treatment of degenerative spondylolisthesis: neither safe nor cost effective  

PubMed Central

Background: With the rise of health care costs, there is increased emphasis on evaluating the cost of a particular surgical procedure for quality adjusted life year (QALY) gained. Recent data have shown that surgical intervention for the treatment of degenerative spondylolisthesis (DS) is as cost-effective as total joint arthroplasty. Despite these excellent outcomes, some argue that the addition of interbody fusion supplemented with bone morphogenetic protein (BMP) enhances the value of this procedure. Methods: This review examines the current research regarding the cost-effectiveness of the surgical management of lumbar DS utilizing interbody fusion along with BMP. Results: Posterolateral spinal fusion with instrumentation for focal lumbar spinal stenosis with DS can provide and maintain improvement in self-reported quality of life. Based on the available literature, including nonrandomized comparative studies and case series, the addition of interbody fusion along with BMP does not lead to significantly better clinical outcomes and increases costs when compared with more routine posterolateral fusion techniques. Conclusions: To enhance the value of the surgical management for DS, costs must decrease or there should be substantial improvement in effectiveness as measured by clinical outcomes. To date, there is insufficient evidence to support the use of interbody fusion devices along with BMP to treat routine cases of focal stenosis accompanied by DS, which are routinely adequately treated utilizing posterolateral fusion techniques.

Moatz, Bradley; Tortolani, P. Justin

2013-01-01

36

A two-cage reconstruction versus a single mega-cage reconstruction for lumbar interbody fusion: an experimental comparison  

Microsoft Academic Search

Background Interbody cages are used as an adjunct to anterior lumbar interbody fusion, but exposure and insertion of two cages can be difficult. A biomechanical study was performed to compare the stability and exposed surface for fusion obtained with interbody reconstruction using two traditional cylindrical cages (18-mm diameter) vs. a single expanded mega-cage (24-mm diameter). A single-cage technique could result

Hideki Murakami; William C. Horton; Katsuro Tomita; William C. Hutton

2004-01-01

37

A randomized double-blind prospective study of the efficacy of pulsed electromagnetic fields for interbody lumbar fusions  

Microsoft Academic Search

A randomized double-blind prospective study of pulsed electromagnetic fields for lumbar interbody fusions was performed on 195 subjects. There were 98 subjects in the active group and 97 subjects in the placebo group. A brace containing equipment to induce an electromagnetic field was applied to patients undergoing interbody fusion in the active group, and a sham brace was used in

VERT MOONEY

1990-01-01

38

Posterior Lumbar Interbody Fusion via a Unilateral Approach  

PubMed Central

This study sought to determine the outcomes of posterior lumbar interbody fusion (PLIF), via a unilateral approach, in selected patients who presented with unilateral leg pain and segmental instability of the lumbar spine. Patients with a single level of a herniated disc disease in the lumbar spine, unilateral leg pain, chronic disabling lower back pain (LBP), and a failed conservative treatment, were considered for the procedure. A total of 41 patients underwent a single-level PLIF using two PEEK™ (Poly-Ether-Ether-Ketone) cages filled with iliac bone, via a unilateral approach. The patients comprised 21 women and 20 men with a mean age of 41 years (range: 22 to 63 years). Two cages were inserted using a unilateral medial facetectomy and a partial hemilaminectomy. At follow-up, the outcomes were assessed using the Prolo Scale. The success of the fusion was determined by dynamic lumbar radiography and/or computerized tomography scanning. All the patients safely underwent surgery without severe complications. During a mean follow-up period of 26 months, 1 patient underwent percutaneous pedicle screw fixation due to persistent LBP. A posterior displacement of the cage was found in one patient. At the last follow up, 90% of the patients demonstrated satisfactory results. An osseous fusion was present in 85% of the patients. A PLIF, via a unilateral approach, enables a solid union with satisfactory clinical results. This preserves part of the posterior elements of the lumbar spine in selected patients with single level instability and unilateral leg pain.

Shin, Hyun Chul; Yi, Seong; Kim, Sang Hyun; Yoon, Do Heum

2006-01-01

39

Repeated Migration of a Fusion Cage after Posterior Lumbar Interbody Fusion  

PubMed Central

Although posterior lumbar interbody fusion (PLIF) is a widely accepted procedure, perioperative and postoperative complications are still encountered. In particular, cage migration can result in severe sequelae, and revision surgery is technically demanded. Here, we report a rare case of repeated migration of a fusion cage after PLIF. To the best of our knowledge, no report has been previously issued on repeated migration of a fusion cage after PLIF. The authors discuss the radiological and clinical findings of this unusual complication with a review of the literature.

Lee, Jun Gue; Lee, Sung Myung; Shin, Ho

2013-01-01

40

Posterolateral versus posterior interbody fusion in isthmic spondylolisthesis.  

PubMed

Spondylolisthesis is a heterogeneous disorder characterized by subluxation of a vertebral body over another in the sagittal plane. Its most common form is isthmic spondylolisthesis (IS). This study aims to compare clinical outcomes of posterolateral fusion (PLF) with posterior lumbar interbody fusion (PLIF) with posterior instrumentation in the treatment of IS. We performed a randomized prospective study in which 80 patients out of a total of 85 patients with IS were randomly allocated to one of two groups: PLF with posterior instrumentation (group I) or PLIF with posterior instrumentation (group II). Posterior decompression was performed in the patients. The Oswestry low back pain disability (OLBP) scale and Visual Analogue Scale (VAS) were used to evaluate the quality of life (QoL) and pain, respectively. Fisher's exact test was used to evaluate fusion rate and the Mann-Whitney U test was used to compare categorical data. Fusion in group II was significantly better than in group I (p=0.012). Improvement in low back pain was statistically more significant in group I (p=0.001). The incidence of neurogenic claudication was significantly lower in group I than in group II (p=0.004). In group I, there was no significant correlation between slip Meyerding grade and disc space height, radicular pain, and low back pain. There was no significant difference in post-operative complications at 1-year follow-up. Our data showed that PLF with posterior instrumentation provides better clinical outcomes and more improvement in low back pain compared to PLIF with posterior instrumentation despite the low fusion rate. PMID:22260338

Farrokhi, Majid Reza; Rahmanian, Abdolkarim; Masoudi, Mohammad Sadegh

2012-05-20

41

Outcomes of allogenic cages in anterior and posterior lumbar interbody fusion  

Microsoft Academic Search

Interbody lumbar fusions provide a proven logical solution to diseases of the intervertebral discs by eliminating motion of the segment. Historically, there are many techniques to achieve spinal fusion in the lumbar spine. These include anterior, posterior, and foramenal approaches, often in combination with various internal fixation devices. The surgeon's choice of the approach and mechanical or biological implant is

M. E. Janssen; C. Lam; R. Beckham

2001-01-01

42

Posterior lumbar interbody fusion using rhBMP-2  

PubMed Central

The use of biological technologies for the treatment of degenerative spinal diseases has undergone rapid clinical and scientific development. BMP strategies have gained wide support for an inherent potential to improve the ossification process. It has been extensively studied in combination with various techniques for spinal stabilisation from both anterior and posterior approach. We studied the fusion process after implantation of rhBMP-2 in 17 patients with degenerative lumbar spine diseases in combination with dorsal fixation with pedicle screws and poly-ether-ether-ketone (PEEK) interbody cages. We used 12 mg rhBMP-2 carried by collagen sponge, 6 mg in every cage. Patient follow up consisted of pre-operative radiographic and clinical evaluation. Similar post-operative evaluations were performed at 3 and 6 months. Clinical assessment demonstrated clear improvement in all patients despite evidence of vertebral endplate osteoclastic activity in the 3-month radiographs. The 6-month radiograph, however, confirmed evidence of fusion, and no untoward results or outcomes were noted. While previous studies have shown exclusively positive results in both fusion rates and process, our study demonstrated an intermediate morphology at 3 months during the ossification process using Induct Os in combination with peek-cages using a PLIF-technique. The transient resorption of bone surrounding the peek cage did not result in subsidence, pain or complication, and fusion was reached in all cases within a 6-month-controlled evaluation. Although there was no negative influence on clinical outcome, the potential for osteoclastic or metabolic resorption bears watching during the post-surgical follow up.

Schnoring, Mark; Hohaus, Christian; Minkus, Yvonne; Beier, Andre; Ganey, Timothy; Mansmann, Ulrich

2008-01-01

43

Repeated adjacent-segment degeneration after posterior lumbar interbody fusion.  

PubMed

One of the most important sequelae affecting long-term results is adjacent-segment degeneration (ASD) after posterior lumbar interbody fusion (PLIF). Although several reports have described the incidence rate, there have been no reports of repeated ASD. The purpose of this report was to describe 1 case of repeated ASD after PLIF. A 62-year-old woman with L-4 degenerative spondylolisthesis underwent PLIF at L4-5. At the second operation, L3-4 PLIF was performed for L-3 degenerative spondylolisthesis 6 years after the primary operation. At the third operation, L2-3 PLIF was performed for L-2 degenerative spondylolisthesis 1.5 years after the primary operation. Vertebral collapse of L-1 was detected 1 year after the third operation, and the collapse had progressed. At the fourth operation, 3 years after the third operation, vertebral column resection of L-1 and replacement of titanium mesh cages with pedicle screw fixation between T-4 and L-5 was performed. Although the patient's symptoms resolved after each operation, the time between surgeries shortened. The sacral slope decreased gradually although each PLIF achieved local lordosis at the fused segment. PMID:24654745

Okuda, Shinya; Oda, Takenori; Yamasaki, Ryoji; Maeno, Takafumi; Iwasaki, Motoki

2014-05-01

44

Vascular anatomy anterior to lumbosacral transitional vertebrae and implications for anterior lumbar interbody fusion  

Microsoft Academic Search

Background context: Anterior approaches to the lumbosacral spine afford the ideal window to the disc for interbody fusion. Vascular injuries represent the most feared complications of such approaches. Unfortunately, the combination of more procedures being performed, more surgeons at the beginning of the learning curve and less invasive techniques of approach combine to increase the risk of vascular injury in

Bradley K Weiner; Matthew Walker; Robert D Fraser

2001-01-01

45

Interbody Fusion in Thoracolumbar Fractures (T11-L2) Using the Percutaneous Dorsolateral Technique  

Microsoft Academic Search

Background: The authors' concept of reduction and stabilization of thoracolumbar fractures has become more sophisticated. Depending upon the fracture classification, a posterior transpedicular, an isolated anterior or a combined approach is used. Fractures with a low degree of vertebral body comminution and only one-space disk injury are reduced and stabilized by the transpedicular approach. For reliable anterior interbody fusion, the

Peter Wendsche; Ján Ko?iš; Petr Viš?a; Vladimír Mužík

2002-01-01

46

Posterior lumbar interbody fusion versus posterolateral fusion in spondylolisthesis: a prospective controlled study in the Han nationality  

PubMed Central

In this prospective study, our aim was to compare the clinical outcome of posterior lumbar interbody fusion (PLIF) and posterolateral fusion (PLF) in spondylolisthesis. A total of 138 patients with spondylolisthesis were randomly assigned to two groups: those operated on with pedicle screw fixation and posterior lumbar interbody fusion by autografting (PLIF), and those operated on with pedicle screw fixation and posterolateral fusion by autografting (PLF). The patients were followed-up for four years. Clinical evaluation was carried out using the Oswestry disability index (ODI) and pain index (VAS). Radiography was performed preoperatively and postoperatively to assess the fusion. Both surgical procedures were effective, but the PLF group showed more complications related to hardware biomechanics. There was no significant statistical difference in clinical and functional outcome in the two groups. The PLIF group presented a better fusion rate than the PLF group.

Nie, Lin; Zhang, Li

2008-01-01

47

Defatted, gas-sterilised cortical bone allograft for posterior lumbar interbody vertebral fusion  

Microsoft Academic Search

Summary. In posterior lumbar interbody vertebral fusion operations, variously sized, rectangular shaped, defatted, freeze-dried, gas-sterilised\\u000a cortical bone allografts were used in combination with cancellous bone autografts from excised posterior elements. Single-level\\u000a fusion, with or without internal fixation, was undertaken in 38 patients aged 50 years or less with disc herniation or a failed\\u000a discectomy (the younger group) and in 33

M. Kakiuchi; K. Ono

1998-01-01

48

Allograft Cellular Bone Matrix in Extreme Lateral Interbody Fusion: Preliminary Radiographic and Clinical Outcomes  

PubMed Central

Introduction. Extreme lateral interbody fusion (XLIF) is a minimally disruptive alternative for anterior lumbar interbody fusion. Recently, synthetic and allograft materials have been increasingly used to eliminate donor-site pain and complications secondary to autogenous bone graft harvesting. The clinical use of allograft cellular bone graft has potential advantages over autograft by eliminating the need to harvest autograft while mimicking autograft's biologic function. The objective of this study was to examine 12-month radiographic and clinical outcomes in patients who underwent XLIF with Osteocel Plus, one such allograft cellular bone matrix. Methods. Forty (40) patients were treated at 61 levels with XLIF and Osteocel Plus and included in the analysis. Results. No complications were observed. From preoperative to 12-month postoperative followup, ODI improved 41%, LBP improved 55%, leg pain improved 43.3%, and QOL (SF-36) improved 56%. At 12 months, 92% reported being “very” or “somewhat” satisfied with their outcome and 86% being either “very” or “somewhat likely” to choose to undergo the procedure again. Complete fusion was observed in 90.2% (55/61) of XLIF levels. Conclusions. Complete interbody fusion with Osteocel Plus was shown in 90.2% of XLIF levels, with the remaining 9.8% being partially consolidated and progressing towards fusion at 12 months.

Tohmeh, Antoine G.; Watson, Blake; Tohmeh, Mirna; Zielinski, Xavier J.

2012-01-01

49

Posterior interbody fusion using a diagonal cage with unilateral transpedicular screw fixation for lumbar stenosis.  

PubMed

Few reports have described the combined use of unilateral pedicle screw fixation and interbody fusion for lumbar stenosis. We retrospectively reviewed 79 patients with lumbar stenosis. The rationale and effectiveness of unilateral pedicle screw fixation were studied from biomechanical and clinical perspectives, aiming to reduce stiffness of the implant. All patients were operated with posterior interbody fusion using a diagonal cage in combination with unilateral transpedicular screw fixation and had reached the 3-year follow-up interval after operation. The mean operating time was 115 minutes (range=95-150 min) and the mean estimated blood loss was 150 mL (range=100-200 mL). The mean duration of hospital stay was 10 days (range=7-15 days). Clinical outcomes were assessed prior to surgery and reassessed at intervals using Denis' pain and work scales. Fusion status was determined from X-rays and CT scans. At the final follow-up, the clinical results were satisfactory and patients showed significantly improved scores (p<0.01) either on the pain or the work scale. Successful fusion was achieved in all patients. There were no new postoperative radiculopathies, or instances of malpositioned or fractured hardware. Posterior interbody fusion using a diagonal cage with unilateral transpedicular fixation is an effective treatment for decompressive surgery for lumbar stenosis. PMID:21237659

Zhao, Jian; Zhang, Feng; Chen, Xiaoqing; Yao, Yu

2011-03-01

50

The Clinical and Radiological Outcomes of Minimally Invasive Transforaminal Lumbar Interbody Single Level Fusion  

PubMed Central

Study Design This is a retrospective study that was done according to clinical and radiological evaluation. Purpose We analyzed the clinical and radiological outcomes of minimally invasive transforaminal lumbar interbody single level fusion. Overview of Literature Minimally invasive transforaminal lumbar interbody fusion is effective surgical method for treating degenerative lumbar disease. Methods The study was conducted on 56 patients who were available for longer than 2 years (range, 24 to 45 months) follow-up after undergoing minimally invasive transforminal lumbar interbody single level fusion. Clinical evaluation was performed by the analysis of the visual analogue scale (VAS) score and the Oswestry Disability Index (ODI) and the Kirkaldy-Willis score. For the radiological evaluation, the disc space height, the segmental lumbar lordotic angle and the whole lumbar lordotic angle were analyzed. At the final follow-up after operation, the fusion rate was analyzed according to Bridwell's anterior fusion grade. Results For the evaluation of clinical outcomes, the VAS score was reduced from an average of 6.7 prior to surgery to an average of 1.8 at the final follow-up. The ODI was decreased from an average of 36.5 prior to surgery to an average of 12.8 at the final follow-up. In regard to the clinical outcomes evaluated by the Kirkaldy-Willis score, better than good results were obtained in 52 cases (92.9%). For the radiological evaluation, the disc space height (p = 0.002), and the whole lumbar lordotic angle (p = 0.001) were increased at the final follow-up. At the final follow-up, regarding the interbody fusion, radiological union was obtained in 54 cases (95.4%). Conclusions We think that if surgeons become familiar with the surgical techniques, this is a useful method for minimally invasive spinal surgery.

Chung, Hung-Tae; Kim, Dong-Jun; Kim, Sang-Hyuk; Jeon, Sang-Ho

2011-01-01

51

A novel synthetic material for spinal fusion: a prospective clinical trial of porous bioactive titanium metal for lumbar interbody fusion  

Microsoft Academic Search

The objective of this study was to establish the efficacy and safety of porous bioactive titanium metal for use in a spinal\\u000a fusion device, based on a prospective human clinical trial. A high-strength spinal interbody fusion device was manufactured\\u000a from porous titanium metal. A bioactive surface was produced by simple chemical and thermal treatment. Five patients with\\u000a unstable lumbar spine

Shunsuke FujibayashiMitsuru; Mitsuru Takemoto; Masashi Neo; Tomiharu Matsushita; Tadashi Kokubo; Kenji Doi; Tatsuya Ito; Akira Shimizu; Takashi Nakamura

52

Lateral Interbody Fusion for Treatment of Discogenic Low Back Pain: Minimally Invasive Surgical Techniques  

PubMed Central

Low back pain is one of the most common ailments in the general population, which tends to increase in severity along with aging. While few patients have severe enough symptoms or underlying pathology to warrant surgical intervention, in those select cases treatment choices remain controversial and reimbursement is a substancial barrier to surgery. The object of this study was to examine outcomes of discogenic back pain without radiculopathy following minimally-invasive lateral interbody fusion. Twenty-two patients were treated at either one or two levels (28 total) between L2 and 5. Discectomy and interbody fusion were performed using a minimallyinvasive retroperitoneal lateral transpsoas approach. Clinical and radiographic parameters were analyzed at standard pre- and postoperative intervals up to 24 months. Mean surgical duration was 72.1 minutes. Three patients underwent supplemental percutaneous pedicle screw instrumentation. Four (14.3%) stand-alone levels experienced cage subsidence. Pain (VAS) and disability (ODI) improved markedly postoperatively and were maintained through 24 months. Segmental lordosis increased significantly and fusion was achieved in 93% of levels. In this series, isolated axial low back pain arising from degenerative disc disease was treated with minimally-invasive lateral interbody fusion in significant radiographic and clinical improvements, which were maintained through 24 months.

Marchi, Luis; Oliveira, Leonardo; Amaral, Rodrigo; Castro, Carlos; Coutinho, Thiago; Coutinho, Etevaldo; Pimenta, Luiz

2012-01-01

53

Anterior Interbody Fusion with the BAK-Cage in Cervical Spondylosis  

Microsoft Academic Search

Summary   BAK-C is a new autostabilizing interbody cage which is implanted during an anterior cervical procedure to provide stability\\u000a to the motion segment and allow fusion to occur. Special intrumentation is provided with a bone collecting reamer. The system\\u000a utilizes surgical site bone graft as the osteo-inductive material within the implant.\\u000a \\u000a Biomechanical testing indicates improved stability and animal studies show

G. Matge

1998-01-01

54

Clinical Outcome and Fusion Rates after the First 30 Extreme Lateral Interbody Fusions  

PubMed Central

Introduction. The lateral transpsoas approach for lumbar interbody fusion (XLIF) is gaining popularity. Studies examining a surgeon's early experience are rare. We aim to report treatment, complication, clinical, and radiographic outcomes in an early series of patients. Methods. Prospective data from the first thirty patients treated with XLIF by a single surgeon was reviewed. Outcome measures included pain, disability, and quality of life assessment. Radiographic assessment of fusion was performed by computed tomography. Results. Average follow-up was 11.5 months, operative time was 60 minutes per level and blood loss was 50?mL. Complications were observed: clinical subsidence, cage breakage upon insertion, new postoperative motor deficit and bowel injury. Approach side-effects were radiographic subsidence and anterior thigh sensory changes. Two patients required reoperation; microforaminotomy and pedicle screw fixation respectively. VAS back and leg pain decreased 63% and 56%, respectively. ODI improved 41.2% with 51.3% and 8.1% improvements in PCS and MCS. Complete fusion (last follow-up) was observed in 85%. Conclusion. The XLIF approach provides superior treatment, clinical outcomes and fusion rates compared to conventional surgical approaches with lowered complication rates. Mentor supervision for early cases and strict adherence to the surgical technique including neuromonitoring is essential.

Malham, Gregory M.; Ellis, Ngaire J.; Parker, Rhiannon M.; Seex, Kevin A.

2012-01-01

55

Failure of a carbon fiber-reinforced polymer implant used for transforaminal lumbar interbody fusion.  

PubMed

Lumbar interbody fusion is a common procedure owing to the high prevalence of degenerative spinal disorders. During such procedures, carbon fiber-reinforced polymer (CFRP) cages are frequently utilized to fill the void created between adjacent vertebral bodies, to provide mechanical stability, and to carry graft material. Failure of such implants can lead to significant morbidity. We discuss the possible causes leading to the failure of a CFRP cage in a patient with rheumatoid arthritis. Review of a 49-year-old woman who underwent revision anterior lumbar interbody fusion 2 years after posterior instrumentation and transforaminal lumbar interbody fusion at L4-L5 and L5-S1. The patient developed pseudarthrosis at the two previously fused levels with failure of the posterior instrumentation. Revision surgery reveled failure with fragmentation of the CFRP cage at the L5-S1 level. CFRP implants can break if mechanical instability or nonunion occurs in the spinal segments, thus emphasizing the need for optimizing medical management and meticulous surgical technique in achieving stability. PMID:24436878

Sardar, Zeeshan; Jarzem, Peter

2013-12-01

56

Evaluation of an injectable calcium phosphate cement as an autograft substitute for transpedicular lumbar interbody fusion: a controlled, prospective study in the sheep model  

Microsoft Academic Search

Anteroposterior procedures for lumbar interbody fusion usually combine posterior instrumentation with anterior techniques that achieve primary stability for compressive loading: tricortical strut-graft, anterior plating systems, or cages. In comparison to transpedicular lumbar interbody fusion (TLIF), these methods bear the burden of the additional anterior approach. TLIF with autograft, in contrast, does not prove to be clinically sufficient because of its

T. R. Blattert; G. Delling; A. Weckbach

2003-01-01

57

MRI Measurement of Neuroforaminal Dimension at the Index and Supradjacent Levels after Anterior Lumbar Interbody Fusion: A Prospective Study  

PubMed Central

Background Anterior interbody fusion has previously been demonstrated to increase neuroforaminal height in a cadaveric model using cages. No prior study has prospectively assessed the relative change in magnetic resonance imaging (MRI) demonstrated neuroforaminal dimensions at the index and supradjacent levels, after anterior interbody fusion with a corticocancellous allograft in a series of patients without posterior decompression. The objective of this study was to determine how much foraminal dimension can be increased with indirect foraminal decompression alone via anterior interbody fusion, and to determine the effect of anterior lumbar interbody fusion on the dimensions of the supradjacent neuroforamina. Methods A prospective study comparing pre- and postoperative neuroforaminal dimensions on MRI scan among 26 consecutive patients undergoing anterior lumbar interbody fusion without posterior decompression was performed. We studies 26 consecutive patients (50 index levels) that had undergone anterior interbody fusion followed by posterior pedicle screw fixation without distraction or foraminotomy. We used preoperative and postoperative MRI imaging to assess the foraminal dimensions at each operated level on which the lumbar spine had been operated. The relative indirect foraminal decompression achieved was calculated. The foraminal dimension of the 26 supradjacent untreated levels was measured pre- and postoperatively to serve as a control and to determine any effects after anterior interbody fusion. Results In this study, 8 patients underwent 1 level fusion (L5-S1), 12 patients had 2 levels (L4-S1) and 6 patients had 3 levels (L3-S1). The average increase in foraminal dimension was 43.3% (p < 0.05)-19.2% for L3-4, 57.1% for L4-5, and 40.1% for L5-S1. Mean pre- and postoperative supradjacent neuroforaminal dimension measurements were 125.84 mm2 and 124.89 mm2, respectively. No significant difference was noted (p > 0.05). Conclusions Anterior interbody fusion with a coriticocancellous allograft can significantly increase neuroforaminal dimension even in the absence of formal posterior distraction or foraminotomy; anterior interbody fusion with a coriticocancellous allograft has little effect on supradjacent neuroforaminal dimensions.

Sokolowski, Mark J.; Mehbod, Amir A.; Denis, Francis; Garvey, Timothy A.; Perl, John; Transfeldt, Ensor E.

2013-01-01

58

Mechanics of interbody spinal fusion. Analysis of critical bone graft area.  

PubMed

Bone graft subsidence is a serious complication of interbody spinal fusion. In this study, 66 mechanical tests were performed on 35 thoracic vertebral bodies to investigate the in situ mechanics of interbody spinal fusion. The relationships among trabecular bone density, bone strength, and size of bone graft area were analyzed. All vertebral bodies were scanned by quantitative computer tomography (QCT) to determine their bone density before mechanical testing. The decorticated trabecular beds of the vertebral bodies, void of all posterior elements, were loaded in a manner similar to that which occurs after surgical interbody fusion. That is, rectangular blocks of polymethylmethacrylate, representing bone grafts, were used to transfer controlled compressive loads to the decorticated vertebral trabecular surface. Both destructive and nondestructive tests were performed. The relationship between QCT bone density and trabecular bone strength was related by a power function, and, on average, the bone density and trabecular bone strength were 0.137 g/cm3 and 3.97 MPa, respectively. Eighty percent of the vertebral bodies with graft covering 25% of the total end plate area or less failed at loads less than 600 N, while 88% of the vertebral bodies with 30% or greater covered were able to carry a load greater than 600 N. The results suggest that the intrinsic behavior of trabecular bone loaded within the vertebral body is little different from the behavior of the whole body, that QCT bone density is indicative of bone strength, and that interbody graft area should be significantly greater than 30% of the total end plate area to provide a margin of safety.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8367768

Closkey, R F; Parsons, J R; Lee, C K; Blacksin, M F; Zimmerman, M C

1993-06-15

59

Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Perspective on Current Evidence and Clinical Knowledge  

PubMed Central

This paper reviews the current published data regarding open transforaminal lumbar interbody fusion (TLIF) in relation to minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). Introduction. MI-TLIF, a modern method for lumbar interbody arthrodesis, has allowed for a minimally invasive method to treat degenerative spinal pathologies. Currently, there is limited literature that compares TLIF directly to MI-TLIF. Thus, we seek to discuss the current literature on these techniques. Methods. Using a PubMed search, we reviewed recent publications of open and MI-TLIF, dating from 2002 to 2012. We discussed these studies and their findings in this paper, focusing on patient-reported outcomes as well as complications. Results. Data found in 14 articles of the literature was analyzed. Using these reports, we found mean follow-up was 20 months. The mean patient study size was 52. Seven of the articles directly compared outcomes of open TLIF with MI-TLIF, such as mean duration of surgery, length of post-operative stay, blood loss, and complications. Conclusion. Although high-class data comparing these two techniques is lacking, the current evidence supports MI-TLIF with outcomes comparable to that of the traditional, open technique. Further prospective, randomized studies will help to further our understanding of this minimally invasive technique.

Habib, Ali; Smith, Zachary A.; Lawton, Cort D.; Fessler, Richard G.

2012-01-01

60

Caudal Vertebral Body Fractures Following Lateral Interbody Fusion in Nonosteoporotic Patients  

PubMed Central

Background The minimally invasive lateral transpsoas approach for lumbar fusions has become increasingly popular. However, vertebral body fractures have been reported after this procedure, particularly in patients with osteoporosis and patients undergoing multilevel fusions. We evaluated the risk factors for caudal vertebral body fractures in 2 nonosteoporotic patients with single-level disease. Case Reports Two patients presented with several years' history of incapacitating chronic low back pain and intermittent radicular pain. Diagnostic imaging in both cases demonstrated grade 1 degenerative spondylolisthesis. The patients underwent a lateral transpsoas interbody fusion, with lateral plate fixation in 1 patient and standalone lateral fusion in the other. The operations were performed without any incidents and both patients experienced immediate symptom relief. Both patients returned several weeks later with excruciating low back pain, without any postoperative history of trauma or heavy lifting. Diagnostic imaging in both patients showed a coronal fracture of the inferior vertebral body. The patients underwent urgent revision surgery involving posterior supplementation with pedicle screw and rod constructs and posterolateral fusion. Conclusion Caudal vertebral body fracture in patients with normal bone quality is a major potential complication after the minimally invasive lateral approach for lumbar fusions. Risk factors may include placement of a lateral plate, the size of the smaller anteroposterior cage, endplate violation, and oblique placement of the interbody cage.

Tender, Gabriel C.

2014-01-01

61

Transforaminal lumbar interbody fusion using unilateral pedicle screws and a translaminar screw  

PubMed Central

Lumbar spinal fusion is advancing with minimally invasive techniques, bone graft alternatives, and new implants. This has resulted in significant reductions of operative time, duration of hospitalization, and higher success in fusion rates. However, costs have increased as many new technologies are expensive. This study was carried out to investigate the clinical outcomes and fusion rates of a low implant load construct of unilateral pedicle screws and a translaminar screw in transforaminal lumbar interbody fusion (TLIF) which reduced the cost of the posterior implants by almost 50%. Nineteen consecutive patients who underwent single level TLIF with this construct were included in the study. Sixteen patients had a TLIF allograft interbody spacer placed, while in three a polyetheretherketone (PEEK) cage was used. Follow-up ranged from 15 to 54 months with a mean of 32 months. A clinical and radiographic evaluation was carried out preoperatively and at multiple time points following surgery. An overall improvement in Oswestry scores and visual analogue scales for leg and back pain (VAS) was observed. Three patients underwent revision surgery due to recurrence of back pain. All patients showed radiographic evidence of fusion from 9 to 26 months (mean 19) following surgery. This study suggests that unilateral pedicle screws and a contralateral translaminar screw are a cheaper and viable option for single level lumbar fusion.

Lee, Sandra; Vaidya, Rahul

2008-01-01

62

A randomized double-blind prospective study of the efficacy of pulsed electromagnetic fields for interbody lumbar fusions  

SciTech Connect

A randomized double-blind prospective study of pulsed electromagnetic fields for lumbar interbody fusions was performed on 195 subjects. There were 98 subjects in the active group and 97 subjects in the placebo group. A brace containing equipment to induce an electromagnetic field was applied to patients undergoing interbody fusion in the active group, and a sham brace was used in the control group. In the active group there was a 92% success rate, while the control group had a 65% success rate (P greater than 0.005). The effectiveness of bone graft stimulation with the device is thus established.

Mooney, V. (Univ. of California, Irvine (USA))

1990-07-01

63

Clinical, radiological and histological study of the failure of cervical interbody fusions with bone substitutes.  

PubMed

Few histological studies on bone substitutes in human cervical spine are available and the biological processes of bone substitutes are not well documented. The authors studied four failure cases of cervical interbody fusion: two cases with hydroxyapatite (HA), one case with beta-tricalcium phosphate ceramic (beta-TCP) and one case with xenograft (bovine bone). Clinical data showed that all the patients experienced neck pain with or without numbness of upper extremity due to fusion failure. Successful fusions were achieved after the salvage surgeries in which autograft were used. Radiographs showed that radiolucent lines were present in all cases. Two HA substitutes fractured without complications. One of them sank into the vertebral body. Some small beta-TCP fragments were found under the microscope. Histological study demonstrated only a few newly formed bones at the interface of the substitutes. The fragments of HA were encapsulated by fibrous tissue. The degradation process and bone regeneration were more active in beta-TCP than in HA. The intertrabecular spaces of bovine bone were filled with fibrous tissue. The results suggest that a porous calcium phosphate ceramic with special design might assure bone ingrowth and meet the mechanical requirements in cervical interbody fusion. The complications of these materials in the cervical spine should be highlighted. PMID:16429285

Xie, Youzhuan; Chopin, Daniel; Hardouin, Pierre; Lu, Jianxi

2006-08-01

64

Stand-Alone Lateral Interbody Fusion for the Treatment of Low-Grade Degenerative Spondylolisthesis  

PubMed Central

The purpose of this paper was to investigate the stand-alone lateral interbody fusion as a minimally invasive option for the treatment of low-grade degenerative spondylolisthesis with a minimum 24-month followup. Prospective nonrandomized observational single-center study. 52 consecutive patients (67.6 ± 10?y/o; 73.1% female; 27.4 ± 3.4?BMI) with single-level grade I/II single-level degenerative spondylolisthesis without significant spine instability were included. Fusion procedures were performed as retroperitoneal lateral transpsoas interbody fusions without screw supplementation. The procedures were performed in average 73.2 minutes and with less than 50cc blood loss. VAS and Oswestry scores showed lasting improvements in clinical outcomes (60% and 54.5% change, resp.). The vertebral slippage was reduced in 90.4% of cases from mean values of 15.1% preoperatively to 7.4% at 6-week followup (P < 0.001) and was maintained through 24 months (7.1%, P < 0.001). Segmental lordosis (P < 0.001) and disc height (P < 0.001) were improved in postop evaluations. Cage subsidence occurred in 9/52 cases (17%) and 7/52 cases (13%) spine levels needed revision surgery. At the 24-month evaluation, solid fusion was observed in 86.5% of the levels treated. The minimally invasive lateral approach has been shown to be a safe and reproducible technique to treat low-grade degenerative spondylolisthesis.

Marchi, Luis; Abdala, Nitamar; Oliveira, Leonardo; Amaral, Rodrigo; Coutinho, Etevaldo; Pimenta, Luiz

2012-01-01

65

Time-sequential changes of differentially expressed miRNAs during the process of anterior lumbar interbody fusion using equine bone protein extract, rhBMP-2 and autograft  

NASA Astrophysics Data System (ADS)

The precise mechanism of bone regeneration in different bone graft substitutes has been well studied in recent researches. However, miRNAs regulation of the bone formation has been always mysterious. We developed the anterior lumbar interbody fusion (ALIF) model in pigs using equine bone protein extract (BPE), recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge (ACS), and autograft as bone graft substitute, respectively. The miRNA and gene expression profiles of different bone graft materials were examined using microarray technology and data analysis, including self-organizing maps, KEGG pathway and Biological process GO analyses. We then jointly analyzed miRNA and mRNA profiles of the bone fusion tissue at different time points respectively. Results showed that miRNAs, including let-7, miR-129, miR-21, miR-133, miR-140, miR-146, miR-184, and miR-224, were involved in the regulation of the immune and inflammation response, which provided suitable inflammatory microenvironment for bone formation. At late stage, several miRNAs directly regulate SMAD4, Estrogen receptor 1 and 5-hydroxytryptamine (serotonin) receptor 2C for bone formation. It can be concluded that miRNAs play important roles in balancing the inflammation and bone formation.

Chen, Da-Fu; Zhou, Zhi-Yu; Dai, Xue-Jun; Gao, Man-Man; Huang, Bao-Ding; Liang, Tang-Zhao; Shi, Rui; Zou, Li-Jin; Li, Hai-Sheng; Bünger, Cody; Tian, Wei; Zou, Xue-Nong

2014-04-01

66

Time-sequential changes of differentially expressed miRNAs during the process of anterior lumbar interbody fusion using equine bone protein extract, rhBMP-2 and autograft  

NASA Astrophysics Data System (ADS)

The precise mechanism of bone regeneration in different bone graft substitutes has been well studied in recent researches. However, miRNAs regulation of the bone formation has been always mysterious. We developed the anterior lumbar interbody fusion (ALIF) model in pigs using equine bone protein extract (BPE), recombinant human bone morphogenetic protein-2 (rhBMP-2) on an absorbable collagen sponge (ACS), and autograft as bone graft substitute, respectively. The miRNA and gene expression profiles of different bone graft materials were examined using microarray technology and data analysis, including self-organizing maps, KEGG pathway and Biological process GO analyses. We then jointly analyzed miRNA and mRNA profiles of the bone fusion tissue at different time points respectively. Results showed that miRNAs, including let-7, miR-129, miR-21, miR-133, miR-140, miR-146, miR-184, and miR-224, were involved in the regulation of the immune and inflammation response, which provided suitable inflammatory microenvironment for bone formation. At late stage, several miRNAs directly regulate SMAD4, Estrogen receptor 1 and 5-hydroxytryptamine (serotonin) receptor 2C for bone formation. It can be concluded that miRNAs play important roles in balancing the inflammation and bone formation.

Chen, Da-Fu; Zhou, Zhi-Yu; Dai, Xue-Jun; Gao, Man-Man; Huang, Bao-Ding; Liang, Tang-Zhao; Shi, Rui; Zou, Li-Jin; Li, Hai-Sheng; Bünger, Cody; Tian, Wei; Zou, Xue-Nong

2014-03-01

67

Posterior lumbar interbody fusion using one diagonal fusion cage with transpedicular screw/rod fixation.  

PubMed

Posterior lumbar interbody fusion (PLIF) using threaded cages has gained wide popularity for lumbosacral spinal disease. Our biomechanical tests showed that PLIF using a single diagonal cage with unilateral facetectomy does add a little to spinal stability and provides equal or even higher postoperative stability than PLIF using two posterior cages with bilateral facetectomy. Studies also demonstrated that cages placed using a posterior approach did not cause the same increase in spinal stiffness seen with pedicle screw instrumentation, and we concluded that cages should not be used posteriorly without other forms of fixation. On the other hand, placement of two cages using a posterior approach does have the disadvantage of risk to the bilateral nerve roots. We therefore performed a prospective study to determine whether PLIF can be accomplished by utilizing a single diagonal fusion cage with the application of supplemental transpedicular screw/rod instrumentation. Twenty-seven patients underwent a PLIF using one single fusion cage (BAK, Sulzer Spine-Tech, Minneapolis, MN, USA) inserted posterolaterally and oriented anteromedially on the symptomatic side with unilateral facetectomy and at the same level supplemental fixation with a transpedicular screw/rod system. The internal fixation systems included 12 SOCON spinal systems (Aesculap AG, Germany) and 15 TSRH spinal systems (Medtronic Sofamor Danek, USA). The inclusion criteria were grade 1 to 2 lumbar isthmic spondylolisthesis, lumbar degenerative spondylolisthesis, and recurrent lumbar disc herniations with instability. Patients had at least 1 year of low back pain and/or unilateral sciatica and a severely restricted functional ability in individuals aged 28-55 years. Patients with more than grade 2 spondylolisthesis or adjacent-level degeneration were excluded from the study. Patients were clinically assessed prior to surgery by an independent assessor; they were then reassessed at 1, 3, 6, 12, 18, and 24 months postoperatively by the same assessor and put into four categories: excellent, good, fair, and poor. Operative time, blood loss, hospital expense, and complications were also recorded. All patients achieved successful radiographic fusion at 2 years, and this was achieved at 1 year in 25 out of 27 patients. At 2 years, clinical results were excellent in 15 patients, good in 10, fair in 1, and poor in 1. Regarding complications, one patient had a postoperative motor and sensory deficit of the nerve root. Reoperation was required in one patient due to migration of pedicle screws. No implant fractures or deformities occurred in any of the patients. PLIF using diagonal insertion of a single threaded cage with supplemental transpedicular screw/rod instrumentation enables sufficient decompression and solid interbody fusion to be achieved with minimal invasion of the posterior spinal elements. It is a clinically safer, easier, and more economical means of accomplishing PLIF. PMID:12709855

Zhao, Jie; Hou, Tiesheng; Wang, Xinwei; Ma, Shengzhong

2003-04-01

68

9:34 Comparison of impacted femoral ring allografts, threaded cortical bone dowels and titanium cages in lumbar fusion  

Microsoft Academic Search

Purpose of study: To test the efficacy of recombinant human bone morphogenic protein (rhBMP-2), we compared clinical and radiographic outcomes in patients who underwent a single-level anterior lumbar interbody fusion (ALIF) and were treated with impacted femoral rings and autogenous bone graft, threaded cortical allograft dowels or titanium cages. Patients who received dowels or titanium cages were randomized to receive

Kenneth Burkus; John Dorchak

2002-01-01

69

A biomechanical and histological evaluation of a bioresorbable lumbar interbody fusion cage.  

PubMed

Novel spinal interbody fusion cages made of bioactive and bioresorbable composites by a unique forging process were developed. Previous in vitro study demonstrated that these cages marked excellent biomechanical values. The purpose of the present in vivo study was to evaluate the viability and advantage of this forged composite of uncalcined hydroxyapatite/poly L-Lactide (F-u-HA/PLLA) cage radiographically, biomechanically, and histologically, when compared to conventional autologous iliac bone (AIB) and carbon fiber cage (CFC). Twenty-five mature sheep underwent posterior lumbar interbody fusion at L2-3 level with pedicle screws system made of titanium. Three types of interbody fusion implants were grafted: AIB (n = 7), CFCs (n = 9), F-u-HA/PLLA cages (n = 9). Two types of cages were packed with autologous fragmented cancellous bone harvested locally. All animals were euthanized at 120 days after surgery. The fusion scoring using the coronal view CT scans was designed to three-dimensionally evaluate fusion quality within and around cages. The mean CT scores of three groups were 33.3 points, 35.0 points, and 33.6 points in AIB, CFC, and F-u-HA/PLLA cage groups, respectively (full-score: 56 points). Statistical differences were not detected among the three groups. The mean range of motion values among fused groups had no significant difference under all pure loadings. The range of motion showed strong and significant correlation with the CT fusion scores. Histologic results demonstrated that F-u-HA/PLLA cages contacted with the surrounding bone directly, and CFC was encircled with thick fibrous tissue layers without any sign of inflammation around cages. The fusion quality of fused spinal segment using F-u-HA/PLLA cages was equal to that of AIB or CFCs both radiographically and biomechanically. In the histological observation, biocompatibility of F-u-HA/PLLA cage was obviously superior to CFC. It has been confirmed that the novel bioactive and bioresorbable cages had valuable advantages over existing CFC for use in spinal reconstructive surgery. PMID:15585267

Hojo, Yoshihiro; Kotani, Yoshihisa; Ito, Manabu; Abumi, Kuniyoshi; Kadosawa, Tsuyoshi; Shikinami, Yasuo; Minami, Akio

2005-05-01

70

Clinical Outcomes of Extreme Lateral Interbody Fusion in the Treatment of Adult Degenerative Scoliosis  

PubMed Central

Introduction. The use of extreme lateral interbody fusion (XLIF) and other lateral access surgery is rapidly increasing in popularity. However, limited data is available regarding its use in scoliosis surgery. The objective of this study was to evaluate the clinical outcomes of adults with degenerative lumbar scoliosis treated with XLIF. Methods. Thirty consecutive patients with adult degenerative scoliosis treated by a single surgeon at a major academic institution were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Validated clinical outcome scores were obtained on patients preoperatively and at most recent follow-up. Complications were recorded. Results. The study group demonstrated improvement in multiple clinical outcome scores. Oswestry Disability Index scores improved from 24.8 to 19.0 (P?

Caputo, Adam M.; Michael, Keith W.; Chapman, Todd M.; Massey, Gene M.; Howes, Cameron R.; Isaacs, Robert E.; Brown, Christopher R.

2012-01-01

71

Protecting the genitofemoral nerve during direct/extreme lateral interbody fusion (DLIF/XLIF) procedures.  

PubMed

A 77-year-old male presented with a history of severe lower back pain for 10 years with radiculopathy, positive claudication type symptoms in his calf with walking, and severe "burning" in his legs bilaterally with walking. Magnetic resonance imaging (MRI) revealed lumbar stenosis at the L3-L4 and L4-L5 levels. During the direct or extreme lateral interbody fusion (DLIF/XLIF) procedure, bilateral posterior tibial, femoral, and ulnar nerve somatosensory evoked potentials (SSEPs) were recorded with good morphology of waveforms observed. Spontaneous electromyography (S-EMG) and triggered electromyography (T-EMG) were recorded from cremaster and ipsilateral leg muscles. A left lateral retroperitoneal transpsoas approach was used to access the anterior disc space for complete discectomy, distraction, and interbody fusion. T-EMG ranging from 0.05 to 55.0 mA with duration of 200 microsec was used for identification of the genitofemoral nerve using a monopolar stimulator during the approach. The genitofemoral nerve (L1-L2) was identified, and the guidewire was redirected away from the nerve. Post-operatively, the patient reported complete pain relief and displayed no complications from the procedure. Intraoperative SSEPs, S-EMG, and T-EMG were utilized effectively to guide the surgeon's approach in this DLIF thereby preventing any post-operative neurological deficits such as damage to the genitofemoral nerve that could lead to groin pain. PMID:21313792

Jahangiri, Faisal R; Sherman, Jonathan H; Holmberg, Andrea; Louis, Robert; Elias, Jeff; Vega-Bermudez, Francisco

2010-12-01

72

Anterior lumbar interbody fusion for treatment of low back pain  

Microsoft Academic Search

Purpose of study: The spectrum of discogenic pain syndrome ranges from internal disc disruption (IDD), degenerative disc disease (DDD) and segmental instability. After failure of conservative treatment, surgical options would include fusion. This study was performed to determine whether the results of fusion differ between IDD and DDD.Methods used: Patient and radiographic data were entered prospectively on 118 patients who

Ashraf Ragab; Mark Flanum; Charles Galanis; Thomas Zdeblick

2002-01-01

73

Axial lumbar interbody fusion: a 6-year single-center experience  

PubMed Central

Introduction The aim of this study is to report our 6-year single-center experience with L5–S1 axial lumbar interbody fusion (AxiaLIF). Methods A total of 131 patients with symptomatic degenerative disc disease refractory to nonsurgical treatment were treated with AxiaLIF at L5–S1, and were followed for a minimum of 1 year (mean: 21 months). Main outcomes included back and leg pain severity, Oswestry Disability Index score, working status, analgesic medication use, patient satisfaction, and complications. Computed tomography was used to determine postoperative fusion status. Results No intraoperative complications, including vascular, neural, urologic, or bowel injuries, were reported. Back and leg pain severity decreased by 51% and 42%, respectively, during the follow-up period (both P < 0.001). Back function scores improved 50% compared to baseline. Clinical success, defined as improvement ?30%, was 67% for back pain severity, 65% for leg pain severity, and 71% for back function. The employment rate increased from 47% before surgery to 64% at final follow-up (P < 0.001). Less than one in four patients regularly used analgesic medications postsurgery. Patient satisfaction with the AxiaLIF procedure was 83%. The fusion rate was 87.8% at final follow-up. During follow-up, 17 (13.0%) patients underwent 18 reoperations on the lumbar spine, including pedicle screw fixation (n = 10), total disc replacement of an uninvolved level (n = 3), facet screw fixation (n = 3), facet screw removal (n = 1), and interbody fusion at L4–L5 (n = 1). Eight (6.1%) reoperations were at the index level. Conclusion Single-level AxiaLIF is a safe and effective means to achieve lumbosacral fusion in patients with symptomatic degenerative disc disease.

Zeilstra, Dick J; Miller, Larry E; Block, Jon E

2013-01-01

74

7:52 Recombinant human bone morphogenic protSD stem–2 in a posterior lumbar interbody fusion construct  

Microsoft Academic Search

Purpose of study: Recombinant human bone morphogenetic protein (rhBMP)-2 has been demonstrated to form bone in various spine fusion applications as effectively as autologous iliac crest bone, without the morbidity of the graft harvest. Posterior lumbar interbody fusion (PLIF) constructs are commonly used in the treatment of degenerative spinal disease. This study evaluates the use of rhBMP-2 in a PLIF

Joseph Alexander; Charles Branch

2002-01-01

75

Prospective clinical outcomes of revision fusion surgery in patients with pseudarthrosis after posterior lumbar interbody fusions using stand-alone metallic cages  

Microsoft Academic Search

Background contextPosterior lumbar interbody fusion (PLIF) is a popular method of arthrodesis for surgical treatment of instabilities and degenerative conditions of the spine. With the introduction of threaded titanium cage devices, surgeons began performing PLIF procedures using these cages as stand-alone devices. Complications have been reported, however, including pseudarthrosis with persistent pain. Outcomes after revision surgical treatment for these patients

Ezequiel H. Cassinelli; Corey Wallach; Brett Hanscom; Molly Vogt; James D. Kang

2006-01-01

76

Role of femoral ring allograft in anterior interbody fusion of the spine.  

PubMed

A review was carried out on 59 patients (10 males and 49 females) who had anterior interbody fusion performed with femoral ring allograft packed with autograft bone chips with a minimum follow up of 2 years. The average age at the time of surgery was 49.1 year old (26 to 75). The total number of levels grafted was 141. The diagnosis consisted of multiple degenerative disease in 6, degenerative change below the long segment of fusion for scoliosis in 9, osteoporosis with collapsed fracture in 3, pseudarthrosis after posterior laminectomy and fusion in 35, congenital scoliosis in 3, scoliosis in 2 and paralytic scoliosis due to multiple sclerosis in one. The distribution of levels fused was T12-L1 in 6, L1-2 in 12, L2-3 in 17, L3-4 in 22, L4-5 in 35 and L5-S1 in 39. The remaining 10 levels were in the lower thoracic areas (T7-T12). The operations were performed as anterior fusion alone in 13 patients, one-stage anterior and posterior fusion in 26 patients and two-stage surgery in 20 patients. Anterior instrumentation was used in all 141 levels. At average follow-up (33.7 months) there was no significant change in allograft angles (average = 1.6 degrees ). Fusion of the allograft was classified by Bridwell's grading system. At 24 months of the follow up, 97 % of the allografts were in grade I (fully incorporated) and 3% were in grade II (partially incorporated). Compared to 12 months follow-up only 76.2% of the grafts were in grade I, 28 % were in grade II and 0.8% were in grade III. Two patients had deep posterior infections which required further surgery (without resorption of the allograft anteriorly). One patient had a screw migration anteriorly which required removal. Three patients had persistence of radiolucent line at one of the vertebral end plates - graft interfaces but no subsidence of the graft or pain. In conclusion, the femoral ring allograft appeared to benefit the anterior interbody fusion in complex spinal surgery. PMID:12118123

Chotivichit, Areesak; Fujita, Takuya; Wong, Tze-Hong; Kostuik, John P; Sieber, Ann N

2001-12-01

77

Posterior instrumentation and transpedicular interbody fusion. Clinical and radiological results with utilization of CT scans after implant removal  

Microsoft Academic Search

Summary  \\u000a The aim of this retrospective study was to determine the late result after operative treatment of acute thoracolumbar fractures\\u000a and fracture dislocations. 29 patients, treated between 1988 and 1995 at the Department of Trauma Surgery, Hannover Medical\\u000a School with posterior stabilization and interbody fusion with transpedicular cancellous bone grafting, were reexamined 3 1\\/2\\u000a years after surgery. The incorporation and

C. Knop; L. Bastian; U. Lange; M. Blauth

1999-01-01

78

Cantilever Transforaminal Lumbar Interbody Fusion for Upper Lumbar Degenerative Diseases (Minimum 2 Years Follow Up)  

PubMed Central

Purpose To evaluate the clinical outcomes of cantilever transforaminal lumbar interbody fusion (c-TLIF) for upper lumbar diseases. Materials and Methods Seventeen patients (11 males, 6 females; mean ± SD age: 62 ± 14 years) who underwent c-TLIF using kidney type spacers between 2002 and 2008 were retrospectively evaluated, at a mean follow-up of 44.1 ± 12.3 months (2 year minimum). The primary diseases studied were disc herniation, ossification of posterior longitudinal ligament (OPLL), degenerative scoliosis, lumbar spinal canal stenosis, spondylolisthesis, and degeneration of adjacent disc after operation. Fusion areas were L1-L2 (5 patients), L2-L3 (9 patients), L1-L3 (1 patient), and L2-L4 (2 patients). Operation time, blood loss, complications, Japanese Orthopaedic Association (JOA) score for back pain, bone union, sagittal alignment change of fusion level, and degeneration of adjacent disc were evaluated. Results JOA score improved significantly after surgery, from 12 ± 2 to 23 ± 3 points (p < 0.01). We also observed significant improvement in sagittal alignment of the fusion levels, from - 1.0 ± 7.4 to 5.2 ± 6.1 degrees (p < 0.01). Bony fusion was obtained in all cases. One patient experienced a subcutaneous infection, which was cured by irrigation. At the final follow-up, three patients showed degenerative changes in adjacent discs, and one showed corrective loss of fusion level. Conclusion c-TLIF is a safe procedure, providing satisfactory results for patients with upper lumbar degenerative diseases.

Hioki, Akira; Hosoe, Hideo; Sugiyama, Seiichi; Suzuki, Naoki; Shimizu, Katsuji

2011-01-01

79

An emerging field: intersection of ALife and AI  

Microsoft Academic Search

This work attempts to provide a systematical view of the intersection of artificial life (A-Life) and artificial intelligence (AI), focusing on the highlight of this emerging field: adaptive behavior system and adaptive autonomous agent. First of all, A-Life and AI are delineated, and the AI roots of A-Life and A-Life roots of AI are discussed. Based upon the discussions, adaptive

Ying Liao; Yuguo Dong; Julong Lan

2004-01-01

80

Surgical treatment of recurrent lumbar disc herniation by transforaminal lumbar interbody fusion  

PubMed Central

Between 2001 and 2005, 43 patients (average age 54.2, range 36–68 years) with recurrent lumbar disc herniation underwent reoperation with the transforaminal lumbar interbody fusion (TLIF) technique at our unit. All cases were followed up for 24–72 months (mean 45 months) and graded using the Japanese Orthopaedic Association (JOA) score system pre- and post-operation and during the follow-up period. The leg pain of all patients was relieved significantly within one month postoperatively. The mean JOA score was improved from 9.3 before surgery to 25.0 at the final follow-up visit (P<0.0001). The average recovery rate was 86.0% (range 52–100%). General clinical outcome was excellent in 23 (53.5%) patients, good in 14 (32.6%) and fair in 6 (13.9%). The fusion rate was 100% two years postoperatively. Three patients (7%) had transient neurological deficits, which resolved completely within 3 months. There were no major complications. We, therefore, believe the TLIF technique to be an effective procedure with satisfactory clinical results for the treatment of recurrent lumbar disc herniation.

Zhao, Jie; Liu, AiGang; Yuan, Jiandong; Li, Zhonghai

2008-01-01

81

Biomechanical evaluation of three surgical scenarios of posterior lumbar interbody fusion by finite element analysis  

PubMed Central

Background For the treatment of low back pain, the following three scenarios of posterior lumbar interbody fusion (PLIF) were usually used, i.e., PLIF procedure with autogenous iliac bone (PAIB model), PLIF with cages made of PEEK (PCP model) or titanium (Ti) (PCT model) materiel. But the benefits or adverse effects among the three surgical scenarios were still not fully understood. Method Finite element analysis (FEA), as an efficient tool for the analysis of lumbar diseases, was used to establish a three-dimensional nonlinear L1-S1 FE model (intact model) with the ligaments of solid elements. Then it was modified to simulate the three scenarios of PLIF. 10?Nm moments with 400?N preload were applied to the upper L1 vertebral body under the loading conditions of extension, flexion, lateral bending and torsion, respectively. Results Different mechanical parameters were calculated to evaluate the differences among the three surgical models. The lowest stresses on the bone grafts and the greatest stresses on endplate were found in the PCT model. The PCP model obtained considerable stresses on the bone grafts and less stresses on ligaments. But the changes of stresses on the adjacent discs and endplate were minimal in the PAIB model. Conclusions The PCT model was inferior to the other two models. Both the PCP and PAIB models had their own relative merits. The findings provide theoretical basis for the choice of a suitable surgical scenario for different patients.

2012-01-01

82

Durotomy repair in minimally invasive transforaminal lumbar interbody fusion by nonpenetrating clips  

PubMed Central

Background: Closure of the dura defect may be easy to perform in open lumbar surgery but could be difficult in minimally invasive transforaminal lumbar interbody fusions (MIS-TLIF) since MIS-TLIF was done through a small tube, which limited the use of standard dural repair instruments. We used nonpenetrating titanium clips that were originally designed for the vascular anastomoses to repair the dura defect, which is never described in the literature. Methods: We presented a case of spinal stenosis with incidental durotomy while performing MIS-TLIF. We closed the dura laceration with three medium-sized nonpenetrating titanium clips (AnastoClip Vessel Closure System, LeMaitre Vascular, Inc., Burlington, MA). Results: Nonpenetrating titanium clips have the benefits of being technically easy to use, reduced durotomy repair time, decreased bed rest due to related medical complications, superior postoperation with immediate hydrostatic strength, and better reapproximation if it fails to clip successfully. As for the postoperation follow up, clips are tiny and reveal no obvious artifact, especially in cases where the pedicle screws are already causing much artifact. Conclusion: Primary dural closure during MIS-TLIF with clips is an effective way in cases that involve limited tubular space.

Cheng, Yen-Po; Lin, Ping-Yi; Huang, Abel Po-Hao; Cheng, Chun-Yuan; Chen, Chien-Min; Hueng, Dueng-Yuan

2014-01-01

83

Anterior dislodgement of a fusion cage after transforaminal lumbar interbody fusion for the treatment of isthmic spondylolisthesis.  

PubMed

Transforaminal lumbar interbody fusion (TLIF) is commonly used procedure for spinal fusion. However, there are no reports describing anterior cage dislodgement after surgery. This report is a rare case of anterior dislodgement of fusion cage after TLIF for the treatment of isthmic spondylolisthesis with lumbosacral transitional vertebra (LSTV). A 51-year-old man underwent TLIF at L4-5 with posterior instrumentation for the treatment of grade 1 isthmic spondylolisthesis with LSTV. At 7 weeks postoperatively, imaging studies demonstrated that banana-shaped cage migrated anteriorly and anterolisthesis recurred at the index level with pseudoarthrosis. The cage was removed and exchanged by new cage through anterior approach, and screws were replaced with larger size ones and cement augmentation was added. At postoperative 2 days of revision surgery, computed tomography (CT) showed fracture on lateral pedicle and body wall of L5 vertebra. He underwent surgery again for paraspinal decompression at L4-5 and extension of instrumentation to S1 vertebra. His back and leg pains improved significantly after final revision surgery and symptom relief was maintained during follow-up period. At 6 months follow-up, CT images showed solid fusion at L4-5 level. Careful cage selection for TLIF must be done for treatment of spondylolisthesis accompanied with deformed LSTV, especially when reduction will be attempted. Banana-shaped cage should be positioned anteriorly, but anterior dislodgement of cage and reduction failure may occur in case of a highly unstable spine. Revision surgery for the treatment of an anteriorly dislodged cage may be effectively performed using an anterior approach. PMID:24175028

Oh, Hyeong Seok; Lee, Sang-Ho; Hong, Soon-Woo

2013-08-01

84

Anterior Dislodgement of a Fusion Cage after Transforaminal Lumbar Interbody Fusion for the Treatment of Isthmic Spondylolisthesis  

PubMed Central

Transforaminal lumbar interbody fusion (TLIF) is commonly used procedure for spinal fusion. However, there are no reports describing anterior cage dislodgement after surgery. This report is a rare case of anterior dislodgement of fusion cage after TLIF for the treatment of isthmic spondylolisthesis with lumbosacral transitional vertebra (LSTV). A 51-year-old man underwent TLIF at L4-5 with posterior instrumentation for the treatment of grade 1 isthmic spondylolisthesis with LSTV. At 7 weeks postoperatively, imaging studies demonstrated that banana-shaped cage migrated anteriorly and anterolisthesis recurred at the index level with pseudoarthrosis. The cage was removed and exchanged by new cage through anterior approach, and screws were replaced with larger size ones and cement augmentation was added. At postoperative 2 days of revision surgery, computed tomography (CT) showed fracture on lateral pedicle and body wall of L5 vertebra. He underwent surgery again for paraspinal decompression at L4-5 and extension of instrumentation to S1 vertebra. His back and leg pains improved significantly after final revision surgery and symptom relief was maintained during follow-up period. At 6 months follow-up, CT images showed solid fusion at L4-5 level. Careful cage selection for TLIF must be done for treatment of spondylolisthesis accompanied with deformed LSTV, especially when reduction will be attempted. Banana-shaped cage should be positioned anteriorly, but anterior dislodgement of cage and reduction failure may occur in case of a highly unstable spine. Revision surgery for the treatment of an anteriorly dislodged cage may be effectively performed using an anterior approach.

Oh, Hyeong Seok; Lee, Sang-Ho

2013-01-01

85

Allogeneic morphogenetic protein vs. recombinant human bone morphogenetic protein-2 in lumbar interbody fusion procedures: a radiographic and economic analysis  

PubMed Central

Background Since the introduction of rhBMP-2 (Infuse®) in 2002, surgeons have had an alternative substitute to autograft and its related donor site morbidity. Recently, the prevalence of reported adverse events and complications related to the use of rhBMP-2 has raised many ethical and legal concerns for surgeons. Additionally, the cost and decreasing reimbursement landscape of rhBMP-2 use have required identification of a viable alternative. Osteo allogeneic morphogenetic protein (OsteoAMP®) is a commercially available allograft-derived growth factor rich in osteoinductive, angiogenic, and mitogenic proteins. This study compares the radiographic fusion outcomes between rhBMP-2 and OsteoAMP allogeneic morphogenetic protein in lumbar interbody fusion spine procedures. Methods Three hundred twenty-one (321) patients from three centers underwent a transforaminal lumbar interbody fusion (TLIF) or lateral lumbar interbody fusion (LLIF) procedure and were assessed by an independent radiologist for fusion and radiographically evident complications. The independent radiologist was blinded to the intervention, product, and surgeon information. Two hundred and twenty-six (226) patients received OsteoAMP with autologous local bone, while ninety-five (95) patients received Infuse with autologous local bone. Patients underwent radiographs (x-ray and/or CT) at standard postoperative follow-up intervals of approximately 1, 3, 6, 12, and 18 months. Fusion was defined as radiographic evidence of bridging across endplates, or bridging from endplates to interspace disc plugs. Osteobiologic surgical supply costs were also analyzed to ascertain cost differences between OsteoAMP and rhBMP-2. Results OsteoAMP produced higher rates of fusion at 6, 12, and 18 months (p???0.01). The time required for OsteoAMP to achieve fusion was approximately 40% less than rhBMP-2 with approximately 70% fewer complications. Osteobiologic supply costs were 80.5% lower for OsteoAMP patients (73.7% lower per level) than for rhBMP-2. Conclusions Results of this study indicate that OsteoAMP is a viable alternative to rhBMP-2 both clinically and economically when used in TLIF and LLIF spine procedures.

2013-01-01

86

Experience with transforaminal interbody fusion in corrective surgery for adolescent idiopathic scoliosis.  

PubMed

One of the surgical goals during the treatment of adolescent idiopathic scoliosis (AIS) is to preserve segments and thus mobility while achieving a well-balanced spine on all planes. The transforaminal interbody fusion (TLIF) technique allows for a significant degree of rotational correction and thus may allow for preservation of more mobile segments. This retrospective study analyzed the use of TLIF in AIS patients who underwent surgery between 2006 and 2009 at a single center, and discusses the degree of curve correction, complications and outcomes. All curves were classified using the Lenke classification system. Standing posterior-anterior Cobb angle, sagittal and coronal balance, percent correction, and end/stable/neutral/apical vertebra were determined on preoperative, postoperative and follow-up radiographs. Nine patients were identified (eight women and one man) ranging in age from 11.6-18 years. All TLIF procedures were performed at the L2/3 level. Lenke curves included 5CN (n=5), 5BN (n=2), and 6CN (n=2). Average follow-up was 27.4 months (range, 12-57 months). Average postoperative curve correction was 79%. One patient underwent revision surgery. All patients remained stable from a clinical and radiographic standpoint on their last follow-up visit. TLIF is an important adjunct in the surgical management of select AIS patients. By allowing for greater rotational correction, it may be possible to preserve one more mobile segment without decompensation or overcorrection. To our knowledge, this is the first report on the role of TLIF in AIS. Future studies are warranted in determining those who will maximally benefit from this technique. PMID:23702374

Barami, Kaveh; Lincoln, Todd; Bains, Ravinder

2013-09-01

87

Effect of Psychological Status on Outcome of Posterior Lumbar Interbody Fusion Surgery  

PubMed Central

Study Design Prospective longitudinal study. Purpose To determine if preoperative psychological status affects outcome in spinal surgery. Overview of Literature Low back pain is known to have a psychosomatic component. Increased bodily awareness (somatization) and depressive symptoms are two factors that may affect outcome. It is possible to measure these components using questionnaires. Methods Patients who underwent posterior interbody fusion (PLIF) surgery were assessed preoperatively and at follow-up using a self-administered questionnaire. The visual analogue scale (VAS) for back and leg pain severity and the Oswestry Disability Index (ODI) were used as outcome measures. The psychological status of patients was classified into one of four groups using the Distress and Risk Assessment Method (DRAM); normal, at-risk, depressed somatic and distressed depressive. Results Preoperative DRAM scores showed 14 had no psychological disturbance (normal), 39 were at-risk, 11 distressed somatic, and 10 distressed depressive. There was no significant difference between the 4 groups in the mean preoperative ODI (analysis of variance, p = 0.426). There was a statistically and clinically significant improvement in the ODI after surgery for all but distressed somatic patients (9.8; range, -5.2 to 24.8; p = 0.177). VAS scores for all groups apart from the distressed somatic showed a statistically and clinically significant improvement. Our results show that preoperative psychological state affects outcome in PLIF surgery. Conclusions Patients who were classified as distressed somatic preoperatively had a less favorable outcome compared to other groups. This group of patients may benefit from formal psychological assessment before undergoing PLIF surgery.

Lakkol, Sandesh; Budithi, Chakra; Bhatia, Chandra; Krishna, Manoj

2012-01-01

88

Osteolysis in transforaminal lumbar interbody fusion with bone morphogenetic protein-2.  

PubMed

STUDY DESIGN.: Retrospective radiographic review. OBJECTIVE.: To determine the incidence of osteolysis, graft subsidence, and cage migration after recombinant human bone morphogenetic protein-2 (rhBMP-2) use with transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA.: Osteolysis after TLIF is a recently described phenomenon associated with rhBMP-2 use. Although this is typically a self-limiting condition, complications such as graft subsidence and cage migration have been described. The incidence of this is not well defined and most studies use plain radiographs for diagnosis rather than more advanced imaging. This study serves to quantify the risk of osteolysis and its associated graft complications with routine use of computed tomography. METHODS.: A total of 58 patients who underwent primary TLIF from a single surgeon between 2004 and 2007 underwent routine postoperative computed tomographic scan. Seventy-seven levels of fusion were evaluated for osteolysis. All patients received the same dose of rhBMP-2 of 5 mg per level. Imaging was performed immediately postoperative and again at an average of 4.3 months postoperative (range = 2.4-9.0 months). These images were evaluated for the presence of osteolysis, graft subsidence, and cage migration. These changes were then graded according to their severity. RESULTS.: Osteolysis was found in 16 of the 58 (27.6%) patients and 19 of the 77 (24.7%) levels treated. No significant difference was found between single and two-level fusions. The degree of osteolysis ranged from 3 to 20 mm with an average of 12.5 mm. The osteolysis was characterized as severe (>1 cm) in 12 of the 19 levels. Of the patients with osteolysis, 31.6% demonstrated graft subsidence all of which occurred with severe osteolytic defects. Migration of the intervertebral cage was found in 8.8% of patients. CONCLUSION.: rhBMP-2 use with TLIF is associated with a significant risk of postoperative osteolysis. Patients who demonstrated postoperative osteolysis were associated with significant risk of subsidence or migration of the intervertebral cage. The clinical implications of these changes are not currently known. PMID:21217443

Knox, Jeffrey B; Dai, Joseph M; Orchowski, Joseph

2011-04-15

89

Comparison of the biomechanical stability of dense cancellous allograft with tricortical iliac autograft and fibular allograft for cervical interbody fusion.  

PubMed

Several choices are available for cervical interbody fusion after anterior cervical discectomy. A recent option is dense cancellous allograft (CS) which is characterized by an open-matrix structure that may promote vascularization and cellular penetration during early osseous integration. However, the biomechanical stability of CS should be comparable to that of the tricortical iliac autograft (AG) and fibular allograft (FA) to be an acceptable alternative to these materials. The purpose of this study was to compare the initial biomechanical stability of CS to that of AG and FA in a one-level anterior cervical discectomy and interbody fusion (ACDF) model. Twelve human cervical spines (C3-T1) were loaded in six modes of motion and evaluated under three conditions: (1) intact, (2) after ACDF using CS, AG, and FA in alternating sequences, and (3) after ACDF with anterior plating. Three reflective markers were placed on the adjacent vertebral bodies. Intervertebral motion was measured with a video-based motion-capture system (MacReflex, Qualisys, Sweden). Torques were applied to a maximum of 2.0 N m. The range-of-motion and neutral-zone values measured in each loading mode were compared. No graft material displayed significant differences in biomechanical stability in any of the tested loading modes, suggesting that the initial stability of CS is comparable to that of AG and FA. Anterior cervical plating significantly increased biomechanical stability in all modes. PMID:16429289

Ryu, Stephen I; Lim, Jesse T; Kim, Sung-Min; Paterno, Josemaria; Willenberg, Rafer; Kim, Daniel H

2006-09-01

90

Comparison of the biomechanical stability of dense cancellous allograft with tricortical iliac autograft and fibular allograft for cervical interbody fusion  

PubMed Central

Several choices are available for cervical interbody fusion after anterior cervical discectomy. A recent option is dense cancellous allograft (CS) which is characterized by an open-matrix structure that may promote vascularization and cellular penetration during early osseous integration. However, the biomechanical stability of CS should be comparable to that of the tricortical iliac autograft (AG) and fibular allograft (FA) to be an acceptable alternative to these materials. The purpose of this study was to compare the initial biomechanical stability of CS to that of AG and FA in a one-level anterior cervical discectomy and interbody fusion (ACDF) model. Twelve human cervical spines (C3–T1) were loaded in six modes of motion and evaluated under three conditions: (1) intact, (2) after ACDF using CS, AG, and FA in alternating sequences, and (3) after ACDF with anterior plating. Three reflective markers were placed on the adjacent vertebral bodies. Intervertebral motion was measured with a video-based motion-capture system (MacReflex, Qualisys, Sweden). Torques were applied to a maximum of 2.0 N m. The range-of-motion and neutral-zone values measured in each loading mode were compared. No graft material displayed significant differences in biomechanical stability in any of the tested loading modes, suggesting that the initial stability of CS is comparable to that of AG and FA. Anterior cervical plating significantly increased biomechanical stability in all modes.

Lim, Jesse T.; Kim, Sung-Min; Paterno, Josemaria; Kim, Daniel H.

2006-01-01

91

Anterolateral Corrective Lumbar Corpectomy and Interbody Fusion by Using Extended Screw Fixation without Posterior Instrumentation for Posttraumatic Kyphosis  

PubMed Central

A 26-year-old paraplegic schizophrenic Japanese woman suffered from severe kyphosis and back pain derived from lumbar burst fractures caused by jumping. She had already undergone resection of the L1 and L2 spinous processes for sharp angular kyphosis, but she still had severe kyphosis and back pain at the L1 and L2. Radiographical examination revealed fused anterior columns at L1 and L2 with severe local kyphosis and a significantly decreased percutaneous distance in the back. The patient underwent anterior instrumented bony resection including an L2 vertebral osteotomy: bilateral L2-L3 facetectomy and partial posterior osteotomy of the L2 vertebrae via a posterior approach followed by an anterior corpectomy of the L2 vertebrae and insertion of a cylindrical cage. No posterior instrumentation was used owing to the presence of atrophied paraspinal soft tissues. Lumbar interbody fusion was performed with vertebral body screws extending from T12 to L4 and corresponding anterior distension and posterior compression. The procedure corrected the kyphosis by 15° and enhanced local stability. Postsurgical visual analogue scale improved from 9.0 to 2.0 and Oswestry Disability Index from 40 to 17.8, respectively. In conclusion, we have demonstrated that anterolateral interbody fusion using extended fixation can compensate for posterior corrective surgery.

Yamazaki, Atsuro; Orita, Sumihisa; Sainoh, Takeshi; Yamauchi, Kazuyo; Suzuki, Miyako; Sakuma, Yoshihiro; Kubota, Go; Oikawa, Yasuhiro; Inage, Kazuhide; Nakata, Yukio; Inoue, Gen; Aoki, Yasuchika; Toyone, Tomoaki; Nakamura, Junichi; Miyagi, Masayuki; Takahashi, Kazuhisa; Ohtori, Seiji

2013-01-01

92

The Memory Metal Minimal Access Cage: A New Concept in Lumbar Interbody Fusion--A Prospective, Noncomparative Study to Evaluate the Safety and Performance  

PubMed Central

Study Design/Objective. A single-centre, prospective, non-comparative study of 25 patients to evaluate the performance and safety of the Memory Metal Minimal Access Cage (MAC) in Lumbar Interbody Fusion. Summary of Background Data. Interbody fusion cages in general are designed to withstand high axial loads and in the meantime to allow ingrowth of new bone for bony fusion. In many cages the contact area with the endplate is rather large leaving a relatively small contact area for the bone graft with the adjacent host bone. MAC is constructed from the memory metal Nitinol and builds on the concept of sufficient axial support in combination with a large contact area of the graft facilitating bony ingrowth and ease in minimal access implantation due to its high deformability. Methods. Twenty five subjects with a primary diagnosis of disabling back and radicular leg pain from a single level degenerative lumbar disc underwent an interbody fusion using MAC and pedicle screws. Clinical performance was evaluated prospectively over 2 years using the Oswestry Disability Index (ODI), Short Form 36 questionnaire (SF-36) and pain visual analogue scale (VAS) scores. The interbody fusion status was assessed using conventional radiographs and CT scan. Safety of the device was studied by registration of intra- and post-operative adverse effects. Results. Clinical performance improved significantly (P < .0018), CT scan confirmed solid fusion in all 25 patients at two year follow-up. In two patients migration of the cage occurred, which was resolved uneventfully by placing a larger size at the subsequent revision. Conclusions. We conclude that the Memory Metal Minimal Access Cage (MAC) resulted in 100% solid fusions in 2 years and proved to be safe, although two patients required revision surgery in order to achieve solid fusion.

Kok, D.; Donk, R. D.; Wapstra, F. H.; Veldhuizen, A. G.

2012-01-01

93

The memory metal minimal access cage: a new concept in lumbar interbody fusion-a prospective, noncomparative study to evaluate the safety and performance.  

PubMed

Study Design/Objective. A single-centre, prospective, non-comparative study of 25 patients to evaluate the performance and safety of the Memory Metal Minimal Access Cage (MAC) in Lumbar Interbody Fusion. Summary of Background Data. Interbody fusion cages in general are designed to withstand high axial loads and in the meantime to allow ingrowth of new bone for bony fusion. In many cages the contact area with the endplate is rather large leaving a relatively small contact area for the bone graft with the adjacent host bone. MAC is constructed from the memory metal Nitinol and builds on the concept of sufficient axial support in combination with a large contact area of the graft facilitating bony ingrowth and ease in minimal access implantation due to its high deformability. Methods. Twenty five subjects with a primary diagnosis of disabling back and radicular leg pain from a single level degenerative lumbar disc underwent an interbody fusion using MAC and pedicle screws. Clinical performance was evaluated prospectively over 2 years using the Oswestry Disability Index (ODI), Short Form 36 questionnaire (SF-36) and pain visual analogue scale (VAS) scores. The interbody fusion status was assessed using conventional radiographs and CT scan. Safety of the device was studied by registration of intra- and post-operative adverse effects. Results. Clinical performance improved significantly (P < .0018), CT scan confirmed solid fusion in all 25 patients at two year follow-up. In two patients migration of the cage occurred, which was resolved uneventfully by placing a larger size at the subsequent revision. Conclusions. We conclude that the Memory Metal Minimal Access Cage (MAC) resulted in 100% solid fusions in 2 years and proved to be safe, although two patients required revision surgery in order to achieve solid fusion. PMID:22567409

Kok, D; Donk, R D; Wapstra, F H; Veldhuizen, A G

2012-01-01

94

The influence of cage positioning and cage type on cage migration and fusion rates in patients with monosegmental posterior lumbar interbody fusion and posterior fixation  

PubMed Central

In posterior lumbar interbody fusion, cage migrations and lower fusion rates compared to autologous bone graft used in the anterior lumbar interbody fusion procedure are documented. Anatomical and biomechanical data have shown that the cage positioning and cage type seem to play an important role. Therefore, the aim of the present study was to evaluate the impact of cage positioning and cage type on cage migration and fusion. We created a grid system for the endplates to analyze different cage positions. To analyze the influence of the cage type, we compared “closed” box titanium cages with “open” box titanium cages. This study included 40 patients with 80 implanted cages. After pedicle screw fixation, 23 patients were treated with a “closed box” cage and 17 patients with an “open box” cage. The follow-up period averaged 25 months. Twenty cages (25%) showed a migration into one vertebral endplate of <3 mm and four cages (5%) showed a migration of ?3 mm. Cage migration was highest in the medio-medial position (84.6%), followed by the postero-lateral (42.9%), and the postero-medial (16%) cage position. Closed box cages had a significantly higher migration rate than open box cages, but fusion rates did not differ. In conclusion, cage positioning and cage type influence cage migration. The medio-medial cage position showed the highest migration rate. Regarding the cage type, open box cages seem to be associated with lower migration rates compared to closed box cages. However, the cage type did not influence bone fusion.

Abbushi, Alexander; Cabraja, Mario; Thomale, Ulrich-Wilhelm; Woiciechowsky, Christian

2009-01-01

95

Applying hierarchical task analysis to improving the patient positioning for direct lateral interbody fusion in spinal surgery.  

PubMed

The present study brings together for the first time the techniques of hierarchical task analysis (HTA), human error identification (HEI), and business process management (BPM) to select practices that can eliminate or reduce potential errors in a surgical setting. We applied the above approaches to the improvement of the patient positioning process for lumbar spine surgery referred to as 'direct lateral interbody fusion' (DLIF). Observations were conducted to gain knowledge on current DLIF positioning practices, and an HTA was constructed. Potential errors associated with the practices specific to DLIF patient positioning were identified. Based on literature review and expert views alternative practices are proposed aimed at improving the DLIF patient positioning process. To our knowledge, this is the first attempt to use BPM in association with HEI/HTA for the purpose of improving the performance and safety of a surgical process - with promising results. PMID:24332824

Al-Hakim, Latif; Maiping, Tanaphon; Sevdalis, Nick

2014-07-01

96

Biomechanical comparison of a new stand-alone anterior lumbar interbody fusion cage with established fixation techniques - a three-dimensional finite element analysis  

PubMed Central

Background Initial promise of a stand-alone interbody fusion cage to treat chronic back pain and restore disc height has not been realized. In some instances, a posterior spinal fixation has been used to enhance stability and increase fusion rate. In this manuscript, a new stand-alone cage is compared with conventional fixation methods based on the finite element analysis, with a focus on investigating cage-bone interface mechanics and stress distribution on the adjacent tissues. Methods Three trapezoid 8° interbody fusion cage models (dual paralleled cages, a single large cage, or a two-part cage consisting of a trapezoid box and threaded cylinder) were created with or without pedicle screws fixation to investigate the relative importance of the screws on the spinal segmental response. The contact stress on the facet joint, slip displacement of the cage on the endplate, and rotational angle of the upper vertebra were measured under different loading conditions. Results Simulation results demonstrated less facet stress and slip displacement with the maximal contact on the cage-bone interface. A stand-alone two-part cage had good slip behavior under compression, flexion, extension, lateral bending and torsion, as compared with the other two interbody cages, even with the additional posterior fixation. However, the two-part cage had the lowest rotational angles under flexion and torsion, but had no differences under extension and lateral bending. Conclusion The biomechanical benefit of a stand-alone two-part fusion cage can be justified. This device provided the stability required for interbody fusion, which supports clinical trials of the cage as an alternative to circumferential fixations.

Chen, Shih-Hao; Tai, Ching-Lung; Lin, Chien-Yu; Hsieh, Pang-Hsing; Chen, Weng-Pin

2008-01-01

97

Lateral Lumbar Interbody Fusion for the Correction of Spondylolisthesis and Adult Degenerative Scoliosis in High-Risk Patients: Early Radiographic Results and Complications  

PubMed Central

Background Lateral lumbar interbody fusion (LLIF) is not associated with many of the complications seen in other interbody fusion techniques. This study used computed tomography (CT) scans, the radiographic gold standard, to assess interbody fusion rates achieved utilizing the LLIF technique in high-risk patients. Methods We performed a retrospective review of patients who underwent LLIF between January 2008 and July 2013. Forty-nine patients underwent nonstaged or staged LLIF on 119 levels with posterior correction and augmentation. Per protocol, patients received CT scans at their 1-year follow-up. Of the 49 patients, 21 patients with LLIF intervention on 54 levels met inclusion criteria. Two board-certified musculoskeletal radiologists and the senior surgeon (JZ) assessed fusion. Results Of the 21 patients, 6 patients had had previous lumbar surgery, and the cohort's comorbidities included osteoporosis, diabetes, obesity, and smoking, among others. Postoperative complications occurred in 12 (57.1%) patients and included anterior thigh pain and weakness in 6 patients, all of which resolved by 6 months. Two cases of proximal junctional kyphosis occurred, along with 1 case of hardware pullout. Two cases of abdominal atonia occurred. By CT scan assessment, each radiologist found fusion was achieved in 53 of 54 levels (98%). The radiologists' findings were in agreement with the senior surgeon. Conclusion Several studies have evaluated LLIF fusion and reported fusion rates between 88%-96%. Our results demonstrate high fusion rates using this technique, despite multiple comorbidities in the patient population. Spanning the ring apophysis with large LLIF cages along with supplemental posterior pedicle screw augmentation can enhance stability of the fusion segment and increase fusion rates.

Waddell, Brad; Briski, David; Qadir, Rabah; Godoy, Gustavo; Houston, Allison Howard; Rudman, Ernest; Zavatsky, Joseph

2014-01-01

98

3:57 Transpedicular lumbar interbody fusion by means of an osteogenic protein–1 (bone morphogenic protein–7)–enhanced hydroxyapatite cement  

Microsoft Academic Search

Purpose of study: In a sheep model, we developed a posterior approach method to treat burst fractures, providing primary stability for axial loading in a sheep model. Using this model and method we tested the efficacy of the osteogenic protein (OP)-1–enhanced hydroxyapatite cement to form an interbody fusion.Methods used: In 36 sheep, L4–L6 were instrumented posteriorly, intervertebral disc L4–L5 was

Thomas Blattert; Guenter Delling; Paresh Dalal; Carol Toth; Arnulf Weckbach

2002-01-01

99

Good Functional Outcome and Adjacent Segment Disc Quality 10 Years after Single-Level Anterior Lumbar Interbody Fusion with Posterior Fixation  

PubMed Central

We reviewed the records of a prospective consecutive cohort to evaluate the clinical performance of anterior lumbar interbody fusion with a titanium box cage and posterior fixation, with emphasis on long-term functional outcome. Thirty-two patients with chronic low back pain underwent anterior lumbar interbody fusion and posterior fixation. Radiological and functional results (visual analogue scale [VAS] and Oswestry score) were evaluated. Adjacent segment degeneration (ASD) was evaluated radiologically and by magnetic resonance imaging (MRI). Twenty-five patients (78%) were available for follow-up. Functional scores showed significant improvement in pain and function up to the 2-year follow-up observation. At 4 years, there was some deterioration of the clinical results. At 10-year follow-up, results remained stable compared with 4-year results. MRI showed ASD in 3/25 (12%) above and 2/10 (20%) below index level (compared with absent preoperatively). ASD could not be related to clinical outcome in this study. Anterior lumbar interbody fusion and posterior fixation is safe and effective. Initial improvement in VAS and Oswestry scores is partly lost at the 4-year follow-up. Good clinical results are maintained at 10-year follow-up and are not related to adjacent segment degeneration.

Horsting, Philip P.; Pavlov, Paul W.; Jacobs, Wilco C.H.; Obradov-Rajic, Marina; de Kleuver, Marinus

2012-01-01

100

Minimally Invasive Transforaminal Lumbar Interbody Fusion with Unilateral Pedicle Screw Fixation: Comparison between Primary and Revision Surgery  

PubMed Central

Minimally invasive surgery with a transforaminal lumbar interbody fusion (MIS TLIF) is an important minimally invasive fusion technique for the lumbar spine. Lumbar spine reoperation is challenging and is thought to have greater complication risks. The purpose of this study was to compare MIS TLIF with unilateral screw fixation perioperative results between primary and revision surgeries. This was a prospective study that included 46 patients who underwent MIS TLIF with unilateral pedicle screw. The patients were divided into two groups, primary and revision MIS TLIF, to compare perioperative results and complications. The two groups were similar in age, sex, and level of operation, and were not significantly different in the length of follow-up or clinical results. Although dural tears were more common with the revision group (primary 1; revision 4), operation time, blood loss, total perioperative complication, and fusion rates were not significantly different between the two groups. Both groups showed substantial improvements in VAS and ODI scores one year after surgical treatment. Revision MIS TLIF performed by an experienced surgeon does not necessarily increase the risk of perioperative complication compared with primary surgery. MIS TLIF with unilateral pedicle screw fixation is a valuable option for revision lumbar surgery.

Kang, Moo Sung; Kim, Kyung Hyun; Kuh, Sung Uk; Chin, Dong Kyu; Kim, Keun Su; Cho, Yong Eun

2014-01-01

101

The impact of sagittal balance on clinical results after posterior interbody fusion for patients with degenerative spondylolisthesis: A Pilot study  

PubMed Central

Background Comparatively little is known about the relation between the sagittal vertical axis and clinical outcome in cases of degenerative lumbar spondylolisthesis. The objective of this study was to determine whether lumbar sagittal balance affects clinical outcomes after posterior interbody fusion. This series suggests that consideration of sagittal balance during posterior interbody fusion for degenerative spondylolisthesis can yield high levels of patient satisfaction and restore spinal balance Methods A retrospective study of clinical outcomes and a radiological review was performed on 18 patients with one or two level degenerative spondylolisthesis. Patients were divided into two groups: the patients without improvement in pelvic tilt, postoperatively (Group A; n = 10) and the patients with improvement in pelvic tilt postoperatively (Group B; n = 8). Pre- and postoperative clinical outcome surveys were administered to determine Visual Analogue Pain Scores (VAS) and Oswestry disability index (ODI). In addition, we evaluated full spine radiographic films for pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), sacrofemoral distance (SFD), and sacro C7 plumb line distance (SC7D) Results All 18 patients underwent surgery principally for the relief of radicular leg pain and back pain. In groups A and B, mean preoperative VAS were 6.85 and 6.81, respectively, and these improved to 3.20 and 1.63 at last follow-up. Mean preoperative ODI were 43.2 and 50.4, respectively, and these improved to 23.6 and 18.9 at last follow-up. In spinopelvic parameters, no significant difference was found between preoperative and follow up variables except PT in Group A. However, significant difference was found between the preoperative and follows up values of PT, SS, TK, LL, and SFD/SC7D in Group B. Between parameters of group A and B, there is borderline significance on preoperative PT, preoperative LL and last follow up SS. Correlation analysis revealed the VAS improvements in Group A were significantly related to postoperative lumbar lordosis (Pearson's coefficient = -0.829; p = 0.003). Similarly, ODI improvements were also associated with postoperative lumbar lordosis (Pearson's coefficient = -0.700; p = 0.024). However, in Group B, VAS and ODI improvements were not found to be related to postoperative lumbar lordosis and to spinopelvic parameters. Conclusion In the current series, patients improving PT after fusion were found to achieve good clinical outcomes in degenerative spondylolisthesis. Overall, our findings show that it is important to quantify sagittal spinopelvic parameters and promote sagittal balance when performing lumbar fusion for degenerative spondylolisthesis.

2011-01-01

102

Intraspinal metalloma causing lumbar stenosis after interbody fusion with cylindrical titanium cages.  

PubMed

Intraspinal metallomas are rare. The authors present a case after implantation of two titanium threaded interbody cages at the L4L5 level, without posterior instrumentation. To their knowledge this is the first case due to intervertebral cages. The lack of additional instrumentation had probably allowed the cages to make contact. Subsequently, friction generated wear debris, which led to the formation of a granuloma, responsible for compression of the dural sac. Intraspinal metallosis should be kept in mind as an infrequent cause of delayed neurological symptoms after spinal surgery with metallic instrumentation. PMID:23409582

Fernández-Baíllo, Nicomedes; Sánchez Marquez, José Miguel; Conde Gallego, Esther; Martín Esteban, Ana

2012-12-01

103

Management of sagittal balance in adult spinal deformity with minimally invasive anterolateral lumbar interbody fusion: a preliminary radiographic study.  

PubMed

Object Minimally invasive (MI) fusion and instrumentation techniques are playing a new role in the treatment of adult spinal deformity. The open pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) are proven segmental methods for improving regional lordosis and global sagittal parameters. Recently the MI anterior column release (ACR) was introduced as a segmental method for treating sagittal imbalance. There is a paucity of data in the literature evaluating the alternatives to PSO and SPO for sagittal balance correction. Thus, the authors conducted a preliminary retrospective radiographic review of prospectively collected data from 2009 to 2012 at a single institution. The objectives of this study were to: 1) investigate the radiographic effect of MI-ACR on spinopelvic parameters, 2) compare the radiographic effect of MI-ACR with PSO and SPO for treatment of adult spinal deformity, and 3) investigate the radiographic effect of percutaneous posterior spinal instrumentation on spinopelvic parameters when combined with MI transpsoas lateral interbody fusion (LIF) for adult spinal deformity. Methods: Patient demographics and radiographic data were collected for 36 patients (9 patients who underwent MI-ACR and 27 patients who did not undergo MI-ACR). Patients included in the study were those who had undergone at least a 2-level MI-LIF procedure; adequate preoperative and postoperative 36-inch radiographs of the scoliotic curvature; a separate second-stage procedure for the placement of posterior spinal instrumentation; and a diagnosis of degenerative scoliosis (coronal Cobb angle > 10° and/or sagittal vertebral axis > 5 cm). Statistical analysis was performed for normality and significance testing. Results Percutaneous transpedicular spinal instrumentation did not significantly alter any of the spinopelvic parameters in either the ACR group or the non-ACR group. Lateral MI-LIF alone significantly improved coronal Cobb angle by 16°, and the fractional curve significantly improved in a subgroup treated with L5-S1 transforaminal lumbar interbody fusion. Fifteen ACRs were performed in 9 patients and resulted in significant coronal Cobb angle correction, lumbar lordosis correction of 16.5°, and sagittal vertebral axis correction of 4.8 cm per patient. Segmental analysis revealed a 12° gain in segmental lumbar lordosis and a 3.1-cm correction of the sagittal vertebral axis per ACR level treated. Conclusions The lateral MI-LIF with ACR has the ability to powerfully restore lumbar lordosis and correct sagittal imbalance. This segmental MI surgical technique boasts equivalence to SPO correction of these global radiographic parameters while simultaneously creating additional disc height and correcting coronal imbalance. Addition of posterior percutaneous instrumentation without in situ manipulation or overcorrection does not alter radiographic parameters when combined with the lateral MI-LIF. PMID:24628129

Manwaring, Jotham C; Bach, Konrad; Ahmadian, Amir A; Deukmedjian, Armen R; Smith, Donald A; Uribe, Juan S

2014-05-01

104

Load- and displacement-controlled finite element analyses on fusion and non-fusion spinal implants.  

PubMed

This study used finite element (FE) analysis with the load-controlled method (LCM) and the displacement-controlled method (DCM) to examine motion differences at the implant level and adjacent levels between fusion and non-fusion implants. A validated three-dimensional intact (INT) L1-L5 FE model was used. At the L3-L4 level, the INT model was modified to surgery models, including the artificial disc replacement (ADR) of ProDisc II, and the anterior lumbar interbody fusion (ALIF) cage with pedicle screw fixation. The LCM imposed 10 Nm moments of four physiological motions and a 150 N preload at the top of L1. The DCM process was in accordance with the hybrid testing protocol. The average percentage changes in the range of motion (ROM) for whole non-operated levels were used to predict adjacent level effects (ALE%). At the implant level, the ALIF model showed similar stability with both control methods. The ADR model using the LCM had a higher ROM than the model using the DCM, especially in extension and torsion. At the adjacent levels, the ALIF model increased ALE% (at least 17 per cent) using the DCM compared with the LCM. The ADR model had an ALE% close to that of the INT model, using the LCM (average within 6 per cent), while the ALE% decreased when using the DCM. The study suggests that both control methods can be adopted to predict the fusion model at the implant level, and similar stabilization characteristics can be found. The LCM will emphasize the effects of the non-fusion implants. The DCM was more clinically relevant in evaluating the fusion model at the adjacent levels. In conclusion, both the LCM and the DCM should be considered in numerical simulations to obtain more realistic data in spinal implant biomechanics. PMID:19278192

Zhong, Z-C; Chen, S-H; Hung, C-H

2009-02-01

105

Screw Placement Accuracy for Minimally Invasive Transforaminal Lumbar Interbody Fusion Surgery: A Study on 3-D Neuronavigation-Guided Surgery  

PubMed Central

Purpose?The aim of this study was to assess the impact of 3-D navigation for pedicle screw placement accuracy in minimally invasive transverse lumbar interbody fusion (MIS-TLIF). Methods?A retrospective review of 52 patients who had MIS-TLIF assisted with 3D navigation is presented. Clinical outcomes were assessed with the Oswestry Disability Index (ODI), Visual Analog Scales (VAS), and MacNab scores. Radiographic outcomes were assessed using X-rays and thin-slice computed tomography. Result?The mean age was 56.5 years, and 172 screws were implanted with 16 pedicle breaches (91.0% accuracy rate). Radiographic fusion rate at a mean follow-up of 15.6 months was 87.23%. No revision surgeries were required. The mean improvement in the VAS back pain, VAS leg pain, and ODI at 11.3 months follow-up was 4.3, 4.5, and 26.8 points, respectively. At last follow-up the mean postoperative disc height gain was 4.92?mm and the mean postoperative disc angle gain was 2.79 degrees. At L5–S1 level, there was a significant correlation between a greater disc space height gain and a lower VAS leg score. Conclusion?Our data support that application of 3-D navigation in MIS-TLIF is associated with a high level of accuracy in the pedicle screw placement.

Torres, Jorge; James, Andrew R.; Alimi, Marjan; Tsiouris, Apostolos John; Geannette, Christian; Hartl, Roger

2012-01-01

106

Comparative Study of Posterior Lumbar Interbody Fusion via Unilateral and Bilateral Approaches in Patients with Unilateral Leg Symptoms  

PubMed Central

Objective We investigated the clinical and radiological advantages of unilateral laminectomy in posterior lumbar interbody fusion (PLIF) procedure comparing with bilateral laminectomy, under the same procedural condition including bilateral instrumentation and insertion of two cages, in patients with degenerative lumbar disease with unilateral leg symptoms. Methods We retrospectively reviewed 124 consecutive cases of PLIF via unilateral or bilateral approach between January 2006 and April 2010. In 80 cases (bilateral group), two cages were inserted via bilateral laminectomy, and in 44 cases (unilateral group), via unilateral laminectomy. The average follow-up duration was 29.5 months. The clinical outcomes were evaluated with the Visual Analogue Scale (VAS) and the Oswestry disability index (ODI). The fusion rates and disc space heights were determined by dynamic standing radiographs and/or computed tomography. Operative times, intra-operative and post-operative blood losses and hospitalization periods were also evaluated. Results In clinical evaluation, the VAS and ODI scores showed excellent outcomes in both groups. There were no significant differences in term of fusion rate, but the perioperative blood loss and the operative time of the unilateral group were lower than that of the bilateral group. Conclusion Unilateral laminectomy can minimize the operative time and perioperative blood loss in PLIF procedure. However, the different preoperative disc height between two groups is a limitation of this study. Despite this limitation, solid fusion and satisfactory symptomatic improvement could be achieved uniquely by our surgical method. This surgical method can be an alternative surgical technique in patients with unilateral leg pain.

Lee, Jong-Won; Kwon, Ki-Young; Rhee, Jong-Joo; Hur, Jin-Woo; Lee, Hyun-Koo

2011-01-01

107

Minimally Invasive Lateral Lumbar Interbody Fusion: Clinical and Radiographic Outcome at a Minimum 2-year Follow-up.  

PubMed

STUDY DESIGN:: Retrospective case series. OBJECTIVE:: To determine the clinical and radiographic outcomes of patients undergoing minimally invasive lateral lumbar interbody fusion (LLIF) with a minimum 2-year follow-up. SUMMARY OF BACKGROUND DATA:: Minimally invasive LLIF is performed through a lateral, retroperitoneal, transpsoas approach. This procedure is characterized by the use of a tubular retractor to minimize tissue damage and real-time neuromonitoring to ensure safe passage through the psoas muscle. To date, advantages of minimal invasive LLIF, compared to open procedures, has been limited to early postoperative outcomes and complications, with the longest mean follow-up duration of 22 months. METHODS:: 118 patients who underwent minimally invasive LLIF with a minimum of 2 years follow-up were included in this study. Clinical outcomes were determined by using Visual Analog Score (VAS) for the degree of pain (trunk or lower extremity), and Oswestry Disability Index (ODI) and Short Form-12 (SF-12) scoring methods for patient function. Radiographic evaluations included (i) disc height, (ii) segmental coronal angulation, (iii) segmental lordotic angulation, (iv) Cobb angle, (v) cage subsidence, and (vi) fusion status. Data were statistically tested using either paired Students-t-test or Wilcoxon matched pair test. Significance levels was set at P<0.05. RESULTS:: We found (i) that the VAS for pain, Oswestry Disability Index and the physical components summary, but not the mental components summary of Short Form-12 improved significantly at the follow-up, (ii) that disc height, coronal angulation, and lordotic angulation at each level and the Cobb angle were restored at the statistically significant extent, (iii) that successful fusion was achieved in 209 levels (88%), and (iv) that transient thigh pain was the most frequent complications seen in 36% of the patients. Conclusions. Our results support the efficacy of minimally invasive LLIF in improvements of clinical and radiographic features. PMID:22964885

Kotwal, Suhel; Kawaguchi, Satoshi; Lebl, Darren; Hughes, Alexander; Huang, Russel; Sama, Andrew; Cammisa, Frank; Girardi, Federico

2012-09-01

108

Minimally Invasive Multi-Level Posterior Lumbar Interbody Fusion Using a Percutaneously Inserted Spinal Fixation System : Technical Tips, Surgical Outcomes  

PubMed Central

Objective There are technical limitations of multi-level posterior pedicle screw fixation performed by the percutaneous technique. The purpose of this study was to describe the surgical technique and outcome of minimally invasive multi-level posterior lumbar interbody fusion (PLIF) and to determine its efficacy. Methods Forty-two patients who underwent mini-open PLIF using the percutaneous screw fixation system were studied. The mean age of the patients was 59.1 (range, 23 to 78 years). Two levels were involved in 32 cases and three levels in 10 cases. The clinical outcome was assessed using the visual analog scale (VAS) and Low Back Outcome Score (LBOS). Achievement of radiological fusion, intra-operative blood loss, the midline surgical scar and procedure related complications were also analyzed. Results The mean follow-up period was 25.3 months. The mean LBOS prior to surgery was 34.5, which was improved to 49.1 at the final follow up. The mean pain score (VAS) prior to surgery was 7.5 and it was decreased to 2.9 at the last follow up. The mean estimated blood loss was 238 mL (140-350) for the two level procedures and 387 mL (278-458) for three levels. The midline surgical scar was 6.27 cm for two levels and 8.25 cm for three level procedures. Complications included two cases of asymptomatic medial penetration of the pedicle border. However, there were no signs of neurological deterioration or fusion failure. Conclusion Multi-level, minimally invasive PLIF can be performed effectively using the percutaneous transpedicular screw fixation system. It can be an alternative to the traditional open procedures.

Kim, Hyeun Sung; Park, Keun Ho; Ju, Chag Il; Lee, Seung Myung; Shin, Ho

2011-01-01

109

Posterior Lumbar Interbody Fusion Using a Unilateral Single Cage and a Local Morselized Bone Graft in the Degenerative Lumbar Spine  

PubMed Central

Background We retrospectively evaluated the clinical and radiological outcomes of posterior lumbar interbody fusion (PLIF) with using a unilateral single cage and a local morselized bone graft. Methods Fifty three patients who underwent PLIF with a unilateral single cage filled with local morselized bone graft were enrolled in this study. The average follow-up duration was 31.1 months. The clinical outcomes were evaluated with using the visual analogue scale (VAS) at the pre-operative period, at 1 year post-operation and at the last follow-up, the Oswestry Disability Index, the Prolo scale and the Kim & Kim criteria at the last follow-up; the radiological outcomes were evaluated according to the change of bone bridging, the radiolucency, the instablity and the disc height. Results For the clinical evaluation, the VAS pain index, the Oswestry Disability Index, the Prolo scale and the Kim & Kim criteria showed excellent outcomes. For the the radiological evaluation, 52 cases showed complete bone union at the last follow-up. Regarding the complications, only 1 patient had cage breakage during follow-up. Conclusions PLIF using a unilateral single cage filled with a local morselized bone graft has the advantages of a shorter operation time, less blood loss and a shorter hospital stay, as compared with the PLIF using bilateral cages, for treating degenerative lumbar spine disease. This technique also provides excellent outcomes according to the clinical and radiological evaluation.

Kim, Dong-Hee; Lee, Sang-Soo

2009-01-01

110

Demineralized Bone Matrix, as a Graft Enhancer of Auto-Local Bone in Posterior Lumbar Interbody Fusion  

PubMed Central

Study Design A case controlled study with prospective data collection. Purpose To evaluate the early influence and the final consequence of demineralized bone matrix (DBM) on auto-local bone as a graft enhancer in posterior lumbar interbody fusion (PLIF). Overview of Literature DBM is known as an osteoinductive material; however, it has not been clearly recognized to enhance auto-local bone with a small amount. Methods Patients who had a PLIF were allocated into two groups. Group I (70 cases) used auto-local bone chips and group II (44 cases) used DBM as an additive to auto-local bone, 1 mL per a segment. Group selection was alternated. Early assessment was performed by computed tomography at 6 months and final assessment was done by simple radiography after 24 months at least. The degree of bone formation was assessed by 4 grade scale. Results The subjects of both groups were homogenous and had similar Oswestry Disability Index at final assessment. The ratio of auto-local bone chips and DBM was 6:1. The degree of bone formation at 6 months after surgery was superior in group II. However, there was no significant difference between the two groups at the final assessment. Conclusions DBM was not recognized to enhance auto-local bone with small amount.

Moon, Sang Ho; Kim, Tae Woo; Boo, Kyung Hwan; Hong, Sung Won

2014-01-01

111

The Effect of the Retroperitoneal Transpsoas Minimally Invasive Lateral Interbody Fusion on Segmental and Regional Lumbar Lordosis  

PubMed Central

Background. The minimally invasive lateral interbody fusion (MIS LIF) in the lumbar spine can correct coronal Cobb angles, but the effect on sagittal plane correction is unclear. Methods. A retrospective review of thirty-five patients with lumbar degenerative disease who underwent MIS LIF without supplemental posterior instrumentation was undertaken to study the radiographic effect on the restoration of segmental and regional lumbar lordosis using the Cobb angles on pre- and postoperative radiographs. Mean disc height changes were also measured. Results. The mean follow-up period was 13.3 months. Fifty total levels were fused with a mean of 1.42 levels fused per patient. Mean segmental Cobb angle increased from 11.10° to 13.61° (P < 0.001) or 22.6%. L2-3 had the greatest proportional increase in segmental lordosis. Mean regional Cobb angle increased from 52.47° to 53.45° (P = 0.392). Mean disc height increased from 6.50?mm to 10.04?mm (P < 0.001) or 54.5%. Conclusions. The MIS LIF improves segmental lordosis and disc height in the lumbar spine but not regional lumbar lordosis. Anterior longitudinal ligament sectioning and/or the addition of a more lordotic implant may be necessary in cases where significant increases in regional lumbar lordosis are desired.

Le, Tien V.; Vivas, Andrew C.; Dakwar, Elias; Baaj, Ali A.; Uribe, Juan S.

2012-01-01

112

Remodeling of heat-treated cortical bone allografts for posterior lumbar interbody fusion: serial 10-year follow-up.  

PubMed

We have selected heat-treated bone allografts as the graft material since the Tokai Bone Bank, the first regional bone bank in Japan, was established in 1992. In this study, we examined changes in bone mineral density (BMD), and morphology observed by magnetic resonance imaging (MRI), and histological findings of bone grafts in cases followed up for 7-10 years after bone grafting to grasp the remodeling of heat-treated cortical bone allografts for posterior lumber interbody fusion (PLIF). BMD of bone grafts was reduced by half at 10 years after grafting. MRI revealed that bone grafts were indistinguishable initially in only 22.2% of cases, whereas after a lengthy period of 10 years distinguishable in many cases. Histologically, new bone formation at the graft-host interface was observed earlier, at 1 year after grafting, than that at the periphery of canals in the specimens. The laminated structure of the cortical bone eroded over time, and fragmented bone trabeculae were observed in the specimens at 8 years or longer after grafting, though necrotic bone still remained in some sites. PMID:21773718

Muramatsu, Koichi; Hachiya, Yudo; Izawa, Hiroyuki; Yamada, Harumoto

2012-12-01

113

Slip Reduction Rate between Minimal Invasive and Conventional Unilateral Transforaminal Interbody Fusion in Patients with Low-Grade Isthmic Spondylolisthesis  

PubMed Central

Objective To compare the slip reduction rate and clinical outcomes between unilateral conventional transforaminal lumbar interbody fusion (conventional TLIF) and unilateral minimal invasive TLIF (minimal TLIF) with pedicle screw fixation for treatment of one level low-grade symptomatic isthmic spondylolisthesis. Methods Between February 2008 and April 2012, 25 patients with low-grade isthmic spondylolisthesis underwent conventional TLIF (12 patients) and minimal TLIF (13 patients) in single university hospital by a single surgeon. Lateral radiographs of lumbar spine were taken 12 months after surgery to analyze the degree of slip reduction and the clinical outcome. All measurements were performed by a single observer. Results The demographic data between conventional TLIF and minimal TLIF were not different. Slip percentage was reduced from 15.00% to 8.33% in conventional TLIF, and from 14.15% to 9.62% in minimal TLIF. In both groups, slip percentage was significantly improved postoperatively (p=0.002), but no significant intergroup differences of slip percentage in preoperative and postoperative were found. The reduction rate also not different between conventional TLIF (45.41±28.80%) and minimal TLIF (32.91±32.12%, p=0.318). Conclusion Conventional TLIF and minimal TLIF with pedicle screw fixation showed good slip reduction in patients with one level low-grade symptomatic isthmic spondylolisthesis. The slip percentage and reduction rate were similar in the conventional TLIF and minimal TLIF.

Oh, Chang Hyun; Ji, Gyu Yeul; Jeon, Jae Kyun; Lee, Junho; Hyun, Dong Keun

2013-01-01

114

Radiographic Results of Single Level Transforaminal Lumbar Interbody Fusion in Degenerative Lumbar Spine Disease: Focusing on Changes of Segmental Lordosis in Fusion Segment  

PubMed Central

Background To assess the radiographic results in patients who underwent transforaminal lumbar interbody fusion (TLIF), particularly the changes in segmental lordosis in the fusion segment, whole lumbar lordosis and disc height. Methods Twenty six cases of single-level TLIF in degenerative lumbar diseases were analyzed. The changes in segmental lordosis, whole lumbar lordosis, and disc height were evaluated before surgery, after surgery and at the final follow-up. Results The segmental lordosis increased significantly after surgery but decreased at the final follow-up. Compared to the preoperative values, the segmental lordosis did not change significantly at the final follow-up. Whole lumbar lordosis at the final follow-up was significantly higher than the preoperative values. The disc height was significantly higher in after surgery than before surgery (p = 0.000) and the disc height alter surgery and at the final follow-up was similar. Conclusions When performing TLIF, careful surgical techniques and attention are needed to restore and maintain the segmental lordosis at the fusion level.

Kim, Sang-Bum; Heo, Youn-Moo; Lee, Woo-Suk; Yi, Jin-Woong; Kim, Tae-Kyun; Hwang, Cheol-Mog

2009-01-01

115

Intervertebral disk-like biphasic scaffold--demineralized bone matrix cylinder and poly(polycaprolactone triol malate)--for interbody spine fusion  

PubMed Central

Interbody fusion is an established procedure to preserve disk height and anterior fusion, but fusion with autografts, allografts, and metallic cages has its endogenous shortcomings. The objective of this study is to investigate whether a biphasic scaffold model, the native demineralized bone matrix cylinder in conjunction with degradable biomaterial poly(polycaprolactone triol malate), can be employed as a biological graft for interbody fusion. The poly(polycaprolactone triol malate) was synthesized by polycondensing malic acid and polycaprolactone and then the concentric sheet of poly(polycaprolactone triol malate) was fabricated into the demineralized bone matrix cylinder derived from rabbit femurs. Rabbit chondrocytes were loaded onto the three-dimensional constructs with 1-day in vitro culture and implanted into the subcutaneous dorsal pocket of nude mice. The chondrocytes/scaffold constructs are approximately two folds bigger than the scaffold-alone constructs after 12 weeks of implantation. X-ray and micro-computed tomography imaging showed endochondral bone formation in the chondrocytes/scaffold constructs as early as 4 weeks and showed that the bone intensity increased over time. Histological staining confirmed the above observation. By week 8, lamellar bone tissues were formed inside the demineralized bone matrix cylinder. In addition, the compression biomechanical test showed that the chondrocytes/scaffold constructs produced a significant higher compressive strength compared to the scaffold group. These results demonstrated that the inner-phase poly(polycaprolactone triol malate) degraded over time and was replaced by new bone in an in vivo environment.

Jin, Li; Wan, Yuqing; Shimer, Adam L; Shen, Francis H

2012-01-01

116

Posterior lumbar interbody fusion with stand-alone Trabecular Metal cages for repeatedly recurrent lumbar disc herniation and back pain.  

PubMed

Object Patients with recurrent sciatica due to repeated reherniation of the intervertebral disc carry a poor prognosis for recovery and create a large burden on society. There is no consensus about the best treatment for this patient group. The goal of this study was to evaluate the 12-month results of the placement of stand-alone Trabecular Metal cages in these patients. Methods The authors performed a retrospective analysis of 26 patients with recurrent disc herniations treated with stand-alone posterior lumbar interbody fusion (PLIF) with Trabecular Metal cages. At 1 year patients were evaluated using the Roland Morris Disability Questionnaire (RMDQ) and a visual analog scale (VAS) for back and leg pain. Furthermore, Likert scores of perceived recovery and satisfaction with the treatment were recorded. Lumbar spine radiographs after 1 year were compared with postoperative radiographs to measure subsidence. Stability of the operated segment was assessed using dynamic radiography. Results The patient group consisted of 26 patients (62% male) with a mean age of 45.7 ± 11.4 years (± SD). Patients had a history of 1 (31%), 2 (42%), or more (27%) discectomies at the same level. The mean follow-up period was 15.3 ± 7.3 months. At follow-up the mean VAS score for pain in the affected leg was 36.7 ± 27.9. The mean VAS score for back pain was 42.5 ± 30.2. The mean RMDQ score at follow-up was 9.8 ± 6.2. Twelve (46%) of the 26 patients had a global perceived good recovery. With respect to treatment satisfaction, 18 patients (69%) were content or very content with the operation and would recommend it. Disc height was increased immediately postoperatively, and at the 1-year follow-up it was still significantly higher compared with the preoperative height (mean 41% ± 38.7%, range -25.7 to 126.8, paired t-test, both p < 0.001), although a mean of 7.52% ± 11.6% subsidence occurred (median 2.0% [interquartile range 0.0%-10.9%], p < 0.003). No significant correlation between subsidence and postoperative back pain was found (Spearman's rho -0.2, p = 0.459). Flexion-extension radiographs showed instability in 1 patient. Conclusions Although only 46% of patients reported a good recovery with significant reductions in back and leg pain, 85% of patients reported at least some benefit from the operation, and a marked improvement in working status at follow-up was noted. In view of previously published poor results of instrumented lumbar fusion for patients with failed back surgery syndrome, the present data indicate that Trabecular Metal interbody fusion cages can be used in a stand-alone fashion and should not always need supplemental posterior fixation in patients with recurrent disc herniation without spinal instability, although a long-term follow-up study is warranted. PMID:24678638

Lequin, Michiel B; Verbaan, Dagmar; Bouma, Gerrit J

2014-06-01

117

Spinal fusion  

MedlinePLUS

Vertebral interbody fusion; Posterior spinal fusion; Arthrodesis; Anterior spinal fusion; Spine surgery - spinal fusion ... Spinal fusion is most often done along with other surgical procedures of the spine. It may be done: With ...

118

Surgeons' Exposure to Radiation in Single- and Multi-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion; A Prospective Study  

PubMed Central

Although minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has widely been developed in patients with lumbar diseases, surgeons risk exposure to fluoroscopic radiation. However, to date, there is no studies quantifying the effective dose during MIS-TLIF procedure, and the radiation dose distribution is still unclear. In this study, the surgeons' radiation doses at 5 places on the bodies were measured and the effective doses were assessed during 31 consecutive 1- to 3-level MIS-TLIF surgeries. The operating surgeon, assisting surgeon, and radiological technologist wore thermoluminescent dosimeter on the unshielded thyroid, chest, genitals, right middle finger, and on the chest beneath a lead apron. The doses at the lens and the effective doses were also calculated. Mean fluoroscopy times were 38.7, 53.1, and 58.5 seconds for 1, 2, or 3 fusion levels, respectively. The operating surgeon's mean exposures at the lens, thyroid, chest, genitals, finger, and the chest beneath the shield, respectively, were 0.07, 0.07, 0.09, 0.14, 0.32, and 0.05 mSv in 1-level MIS-TLIF; 0.07, 0.08, 0.09, 0.18, 0.34, and 0.05 mSv in 2-level; 0.08, 0.09, 0.14, 0.15, 0.36, and 0.06 mSv in 3-level; and 0.07, 0.08, 0.10, 0.15, 0.33, and 0.05 mSv in all cases. Mean dose at the operating surgeon's right finger was significantly higher than other measurements parts (P<0.001). The operating surgeon's effective doses (0.06, 0.06, and 0.07 mSv for 1, 2, and 3 fusion levels) were low, and didn't differ significantly from those of the assisting surgeon or radiological technologist. Revision MIS-TLIF was not associated with higher surgeons' radiation doses compared to primary MIS-TLIF. There were significantly higher surgeons' radiation doses in over-weight than in normal-weight patients. The surgeons' radiation exposure during MIS-TLIF was within the safe level by the International Commission on Radiological Protection's guidelines. The accumulated radiation exposure, especially to surgeon's hands, should be carefully monitored.

Funao, Haruki; Ishii, Ken; Momoshima, Suketaka; Iwanami, Akio; Hosogane, Naobumi; Watanabe, Kota; Nakamura, Masaya; Toyama, Yoshiaki; Matsumoto, Morio

2014-01-01

119

The influence of intervertebral disc tissue on anterior spinal interbody fusion: an experimental study on pigs  

Microsoft Academic Search

Intervertebral disc has been shown to be related to low back pain and nerve root injury in pathologic conditions. However, little is known about its influence on spinal fusion. With the development of minimal invasive operations, such as laparoscopic anterior spinal fusion with cages, insufficient discectomy may occur. With its inflammatory properties, the residue nucleus pulposus may have an effect

Haisheng Li; Xuenong Zou; Malene Laursen; Niels Egund; Martin Lind; Cody Bünger

2002-01-01

120

A Multi-center Clinical Study of Posterior Lumbar Interbody Fusion with the Expandable Stand-alone Cage (Tyche(R) Cage) for Degenerative Lumbar Spinal Disorders  

PubMed Central

Objective This multi-center clinical study was designed to determine the long-term results of patients who received a one-level posterior lumbar interbody fusion with expandable cage (Tyche® cage) for degenerative spinal diseases during the same period in each hospital. Methods Fifty-seven patients with low back pain who had a one-level posterior lumbar interbody fusion using a newly designed expandable cage were enrolled in this study at five centers from June 2003 to December 2004 and followed up for 24 months. Pain improvement was checked with a Visual Analogue Scale (VAS) and their disability was evaluated with the Oswestry Disability Index. Radiographs were obtained before and after surgery. At the final follow-up, dynamic stability, quality of bone fusion, interveretebral disc height, and lumbar lordosis were assessed. In some cases, a lumbar computed tomography scan was also obtained. Results The mean VAS score of back pain was improved from 6.44 points preoperatively to 0.44 at the final visit and the score of sciatica was reduced from 4.84 to 0.26. Also, the Oswestry Disability Index was improved from 32.62 points preoperatively to 18.25 at the final visit. The fusion rate was 92.5%. Intervertebral disc height, recorded as 9.94±2.69 mm before surgery was increased to 12.23±3.31 mm at postoperative 1 month and was stabilized at 11.43±2.23 mm on final visit. The segmental angle of lordosis was changed significantly from 3.54±3.70° before surgery to 6.37±3.97° by 24 months postoperative, and total lumbar lordosis was 20.37±11.30° preoperatively and 24.71±11.70° at 24 months postoperative. Conclusion There have been no special complications regarding the expandable cage during the follow-up period and the results of this study demonstrates a high fusion rate and clinical success.

Kim, Jin Wook; Yoon, Seung Hwan; Oh, Seong Hoon; Roh, Sung Woo; Rim, Dae Cheol; Kim, Tae Sung

2007-01-01

121

Quality-of-Life Outcomes With Minimally Invasive Transforaminal Lumbar Interbody Fusion Based on Long-Term Analysis of 304 Consecutive Patients  

PubMed Central

Study Design. This was a prospective clinical study that took place in an outpatient spine clinic. Objective. To demonstrate the short-/long-term outcomes from a large cohort of patients undergoing minimally invasive transforaminal lumbar interbody fusion (MITLIF). Summary of Background Data. Long-term prospective outcomes in patients undergoing minimally invasive spinal fusion for debilitating back pain has not been well studied. Methods. Presenting diagnosis was determined from clinical findings and radiographical (radiograph, magnetic resonance image, computed tomographic scan) evaluations preoperatively. Patients were assessed with outcome measures preoperatively, and postoperatively at 2 weeks, 3 months, 6 months, 12 months, 24 months, and annually 2 to 7 years (mean follow-up: 47 mo) final follow-up. The rate of postoperative complications and reoperations at the initial level of MITLIF and adjacent level(s) were followed. Fusion rates were assessed blinded and independently by radiograph. Results. Visual analogue scale scores decreased significantly from 7.0 preoperatively to 3.5 at mean 47-month follow-up. Oswestry Disability Index scores declined from 43.1 preoperatively to 28.2 at mean 47-month follow-up. Short-Form 36 mental component scores increased from 43.8 preoperatively to 49.7 at 47-month follow-up. Short-Form 36 physical component scores increased from 30.6 preoperatively to 39.6 at 47-month follow-up (P < 0.05). Conclusion. This prospectively collected outcomes study shows long-term statistically significant clinical outcomes improvement after MITLIF in patients with clinically symptomatic spondylolisthesis and degenerative disc disease with or without stenosis. MITLIF resulted in a high rate of spinal fusion and very low rate of interbody fusion failure and/or adjacent segment disease requiring reoperation while reducing postoperative complications. Level of Evidence: 3

Hussain, Namath S.; White, G. Zachary; Begun, Evan M.; Collins, Robert A.; Fahim, Daniel K.; Hiremath, Girish K.; Adbi, Fadumo M.; Yacob, Sammy A.

2014-01-01

122

Late Results of Anterior Cervical Discectomy and Fusion with Interbody Cages  

PubMed Central

Study Design Retrospective analysis. Purpose To evaluate the effectiveness of anterior cervical discectomy with fusion for degenerative cervical disc disease. Overview of Literature Anterior spinal surgery originated in the mid-1950s and graft for fusion was also employed. Currently anterior cervical microdiscectomy and fusion with an intervertebral cage is a widely accepted procedure for treatment of cervical disc hernia. Artificial grafts and cages for fusion are preferred because of their lower morbidity, reduced operating time and acceptable fusion rate. Methods The study involved retrospective analysis and investigation of long-term results for 41 consecutive patients who had undergone anterior cervical discectomy and fusion with an intervertebral cage for cervical disc hernia. The angle of lordosis, segmental height and range of motion were evaluated preoperatively and postoperatively at 1 month and 2 years. The clinical outcome was assessed by the visual analog scale and Odom's criteria. Results The angle of lordosis increased by 2.62° and the range of motion angle increased by 5.14° after the operation. The segmental height did not change. The visual analog scale and Odom's criteria scores decreased significantly after the operation. Conclusions Using a cage in anterior cervical discectomy prevents segmental collapse, so the segmental height and the angle of lordosis are preserved and newly-developed pain does not occur.

Dagl?, Murat; Simsek, Serkan; Bavbek, Murad

2013-01-01

123

Comparison of SpineJet(TM) XL and Conventional Instrumentation for Disk Space Preparation in Unilateral Transforaminal Lumbar Interbody Fusion  

PubMed Central

Objective Although unilateral transforaminal lumbar interbody fusion (TLIF) is widely used because of its benefits, it does have some technical limitations. Removal of disk material and endplate cartilage is difficult, but essential, for proper fusion in unilateral surgery, leading to debate regarding the surgery's limitations in removing the disk material on the contralateral side. Therefore, authors have conducted a randomized, comparative cadaver study in order to evaluate the efficiency of the surgery when using conventional instruments in the preparation of the disk space and when using the recently developed high-pressure water jet system, SpineJet™ XL. Methods Two spine surgeons performed diskectomies and disk preparations for TLIF in 20 lumbar disks. All cadaver/surgeon/level allocations for preparation using the SpineJet™ XL (HydroCision Inc., Boston, MA, USA) or conventional tools were randomized. All assessments were performed by an independent spine surgeon who was unaware of the randomizations. The authors measured the areas (cm2) and calculated the proportion (%) of the disk surfaces. The duration of the disk preparation and number of instrument insertions and withdrawals required to complete the disk preparation were recorded for all procedures. Results The proportion of the area of removed disk tissue versus that of potentially removable disk tissue, the proportion of the area of removed endplate cartilage, and the area of removed disk tissue in the contralateral posterior portion showed 74.5 ± 17.2%, 18.5 ± 12.03%, and 67.55 ± 16.10%, respectively, when the SpineJet™ XL was used, and 52.6 ± 16.9%, 22.8 ± 17.84%, and 51.64 ± 19.63%, respectively, when conventional instrumentations were used. The results also showed that when the SpineJet™ XL was used, the proportion of the area of removed disk tissue versus that of potentially removable disk tissue and the area of removed disk tissue in the contralateral posterior portion were statistically significantly high (p < 0.001, p < 0.05, respectively). Also, compared to conventional instrumentations, the duration required to complete disk space preparation was shorter, and the frequency of instrument use and the numbers of insertions/withdrawals were lower when the SpineJet™ XL was used. Conclusion The present study demonstrates that hydrosurgery using the SpineJet™ XL unit allows for the preparation of a greater portion of disk space and that it is less traumatic and allows for more precise endplate preparation without damage to the bony endplate. Furthermore, the SpineJet™ XL appears to provide tangible benefits in terms of disk space preparation for graft placement, particularly when using the unilateral TLIF approach.

Huh, Han-Yong; Ji, Cheol; Ryu, Kyeong-Sik

2010-01-01

124

Functional outcomes of instrumented posterior lumbar interbody fusion in active-duty US servicemen  

Microsoft Academic Search

Background context: The existing literature lacks a functional outcome study addressing instrumented posterior lumbar fusion surgery in physically active patients. Furthermore, results of operative versus nonoperative treatment in these patients are not clear. Purpose: To evaluate patient-assessed function, pain, and satisfaction and military job performance between servicemen treated operatively and nonoperatively. Study design\\/setting: This is a nonrandomized analysis of consecutive

Major Robert W Molinari; Major Tad Gerlinger

2001-01-01

125

Spinal fusion - series (image)  

MedlinePLUS

Interbody cage fusion uses a hollow threaded titanium or carbon fiber cylinder to fuse two vertebrae together. The diseased disk is removed and two interbody cages are placed in the opening where the diseased ...

126

The rising psoas sign: an analysis of preoperative imaging characteristics of aborted minimally invasive lateral interbody fusions at L4-5.  

PubMed

Minimally invasive lateral interbody fusion for the treatment of degenerative disc disease, spondylolisthesis, or scoliosis is becoming increasingly popular. The approach at L4-5 carries the highest risk of nerve injury given the proximity of the lumbar plexus and femoral nerve. The authors present 3 cases that were aborted during the approach because of pervasive electromyography responses throughout the L4-5 disc space. Preoperative imaging characteristics of psoas muscle anatomy in all 3 cases are analyzed and discussed. In all cases, the psoas muscle on axial views was rising away from the vertebral column as opposed to its typical location lateral to it. Preoperative evaluation of psoas muscle anatomy is important. A rising psoas muscle at L4-5 on axial imaging may complicate a lateral approach. PMID:24606002

Voyadzis, Jean-Marc; Felbaum, Daniel; Rhee, Jay

2014-05-01

127

The NEtherlands Cervical Kinematics (NECK) Trial. Cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in the treatment of cervical disc herniation; a double-blind randomised multicenter study  

PubMed Central

Background Patients with cervical radicular syndrome due to disc herniation refractory to conservative treatment are offered surgical treatment. Anterior cervical discectomy is the standard procedure, often in combination with interbody fusion. Accelerated adjacent disc degeneration is a known entity on the long term. Recently, cervical disc prostheses are developed to maintain motion and possibly reduce the incidence of adjacent disc degeneration. A comparative cost-effectiveness study focused on adjacent segment degeneration and functional outcome has not been performed yet. We present the design of the NECK trial, a randomised study on cost-effectiveness of anterior cervical discectomy with or without interbody fusion and arthroplasty in patients with cervical disc herniation. Methods/Design Patients (age 18-65 years) presenting with radicular signs due to single level cervical disc herniation lasting more than 8 weeks are included. Patients will be randomised into 3 groups: anterior discectomy only, anterior discectomy with interbody fusion, and anterior discectomy with disc prosthesis. The primary outcome measure is symptomatic adjacent disc degeneration at 2 and 5 years after surgery. Other outcome parameters will be the Neck Disability Index, perceived recovery, arm and neck pain, complications, re-operations, quality of life, job satisfaction, anxiety and depression assessment, medical consumption, absenteeism, and costs. The study is a randomised prospective multicenter trial, in which 3 surgical techniques are compared in a parallel group design. Patients and research nurses will be kept blinded of the allocated treatment for 2 years. The follow-up period is 5 years. Discussion Currently, anterior cervical discectomy with fusion is the golden standard in the surgical treatment of cervical disc herniation. Whether additional interbody fusion or disc prothesis is necessary and cost-effective will be determined by this trial. Trial Registration Netherlands Trial Register NTR1289

2010-01-01

128

Assessment of bone graft incorporation by 18 F-fluoride positron-emission tomography/computed tomography in patients with persisting symptoms after posterior lumbar interbody fusion  

PubMed Central

Background Posterior lumbar interbody fusion (PLIF) is a method that allows decompression of the spinal canal and nerve roots by laminectomy combined with fusion by means of intervertebral cages filled with bone graft and pedicle screw fixation. Conventional imaging techniques, such as plain radiography and computed tomography (CT), have limitations to assess bony fusion dynamics. Methods In 16 PLIFs of 15 patients with persisting symptoms, positron-emission tomography (PET)/CT scans were made 60?min after intravenous administration of 156 to 263?MBq of 18?F-fluoride, including 1-mm sliced, high-dose, non-contrast-enhanced CT scanning. Maximal standard uptake values (SUVmax) of various regions were calculated and correlated with abnormalities on CT. Results Subsidence of the cages into the vertebral endplates was the most frequently observed abnormality on CT (in 16 of 27 or 59% of evaluable endplates). Endplate SUVmax values were significantly higher for those patients with pronounced (p?fusion was seen on CT in 63% but showed no correlation to intercorporal SUVmax values. Conclusions With the use of 18?F-fluoride PET/CT, intervertebral cage subsidence appeared to be a prominent finding in this patient group with persisting symptoms, and highly correlating with the degree of PET hyperactivity at the vertebral endplates and pedicle screw entry points. Further study using 18?F-fluoride PET/CT should specifically assess the role of metabolically active subsidence in a prospective patient group, to address its role in nonunion and as a cause of persisting pain.

2012-01-01

129

Long-Term Follow-Up Radiologic and Clinical Evaluation of Cylindrical Cage for Anterior Interbody Fusion in Degenerative Cervical Disc Disease  

PubMed Central

Objective Various procedures have been introduced for anterior interbody fusion in degenerative cervical disc disease including plate systems with autologous iliac bone, carbon cages, and cylindrical cages. However, except for plate systems, the long-term results of other methods have not been established. In the present study, we evaluated radiologic findings for cylindrical cervical cages over long-term follow up periods. Methods During 4 year period, radiologic findings of 138 patients who underwent anterior cervical fusion with cylindrical cage were evaluated at 6, 12, 24, and 36 postoperative months using plain radiographs. We investigated subsidence, osteophyte formation (anterior and posterior margin), cage direction change, kyphotic angle, and bone fusion on each radiograph. Results Among the 138 patients, a minimum of 36 month follow-up was achieved in 99 patients (mean follow-up : 38.61 months) with 115 levels. Mean disc height was 7.32 mm for preoperative evaluations, 9.00 for immediate postoperative evaluations, and 4.87 more than 36 months after surgery. Osteophytes were observed in 107 levels (93%) of the anterior portion and 48 levels (41%) of the posterior margin. The mean kyphotic angle was 9.87° in 35 levels showing cage directional change. There were several significant findings : 1) related subsidence [T-score (p=0.039) and anterior osteophyte (p=0.009)], 2) accompanying posterior osteophyte and outcome (p=0.05). Conclusion Cage subsidence and osteophyte formation were radiologically observed in most cases. Low T-scores may have led to subsidence and kyphosis during bone fusion although severe neurologic aggravation was not found, and therefore cylindrical cages should be used in selected cases.

Kim, Suhyeong; Yi, Hyeon-Joong; Bak, Koang Hum; Kim, Dong Won; Lee, Yoon Kyoung

2012-01-01

130

Mid-term Clinical Outcomes of Stand-alone Posterior Interbody Fusion with Rectangular Cages: A 4-year-minimum Follow-up  

PubMed Central

Objective We sought to determine minimum 4 years of clinical outcomes including fusion rate, revision rate and complications of patients who underwent placement of rectangular stand-alone cages. Methods Thirty-three cases of degenerative spine that had been followed for at least 4-years were reviewed retrospectively. Cages were inserted at L4-L5 level or L5-S1 in 27 or in 6 cases respectively. Visual analogue scale (VAS), Odom's criteria, fusion rate, intervertebral disc height and lumbar lordosis were determined pre- and post-operatively on standing x-rays. Amount of intra- and postoperative blood loss, total volume transfused, duration of surgery and perioperative complications were also evaluated. Results The mean VAS score of back pain and sciatica were improved from 8.0 and 7.0 points to 3.4 and 2.4 during 1 years follow-up visit and the scores was raised gradually. Also, during the follow-up, 94% of patients showed excellent or good outcomes by the Odom's criteria. Intervertebral disc height was increased from 8.2±1.4mm to 9.2±1.9mm at the first year of follow-up, however, found to be decreased and stabilized to 8.3±1.8mm after 2 years. The fusion rate was approximately 91% after 4 year postoperative. The segmental angle of lordosis was increased significantly by two years but it was not maintained after four years. A statistically insignificant change in total lumbar lordosis was also observed. Three patients (9%) had experienced perioperative complications. Conclusion The use of rectangular stand-alone cages for posterior lumbar interbody fusion (PLIF) resulted in a various degree of subsidence and demonstrate very low complication rate, high functional stability and improved clinical outcomes in patients with degenerative lumbar disc disease.

Cho, Kyung Rae; Lee, Sun-Ho; Kim, Eun Sang

2013-01-01

131

[The design, preparation and compressive strength testing of interbody fusion cages made from a composite of multi-amino acid copolymer/tri-calcium phosphate].  

PubMed

This research was to design and prepare interbody fusion cages using composite materials of multi-amino acid copolymer/tri-calcium phosphate (MAACP/TCP) and to test compressive strength of the cages. 16 specimens of C3-4 segments from female adult goats were scanned by X-ray to exclude disease of cervical spine, and then anatomical data were measured, i. e. disc space height of C3-4 segment (DSH), sagittal diameter of C3 lower endplate (SDLE3), sagittal diameter of C4 upper endplate (SDUE4), coronary diameter of C3 lower endplate (CDLE3), and coronary diameter of C4 upper endplate (CDUE4). According to the anatomical data, we designed and prepared the interbody fusion cage using the composite of MAACP/TCP and titanium with the same sizes. The MAACP/TCP Cages were made with the method of injection molding and finish machining, and titanium Cages were made with machining. In the testing of compressive strength of Cages, the specimens were divided into three groups, tricortical iliac crest bone group (isolated from goats), MAACP/TCP Cage group and titanium Cage group. There were 8 specimens in every group with the same sizes, the length of 12 mm, the width of 10 mm, and the height of 6 mm. The compressive strength of all specimens was tested on a universal testing machine. The values of DSH, SDLE3, SDUE4, CDLE3 and CDUE4 were (4.78 +/- 0.17) mm, (15.06 +/- 0.53) mm, (12.46 +/- 0.44) mm, (14.47 +/- 0.51) mm and (12.15 +/- 0.65) mm, respectively. MAACP/TCP Cage was successfully designed and made with a compressive strength of 76.34 MPa, which was much higher than that of tricortical iliac crest bone (18.41 MPa). The maximal loading of universal testing machine was 50 000 N, so the compressive strength of titanium Cages, whose value should be more than 541.35 MPa, could not be tested precisely. It is feasible to make cages with MAACP/TCP composite, and the compressive strength of MAACP/TCP Cages was much higher than that of tricortical iliac crest bone isolated from goats. PMID:22295701

Zhou, Chungnang; Song, Yueming; Tu, Chongqi; Pei, Fuxing; Duan, Hong; Liu, Limin; Li, Hong

2011-12-01

132

Posterior decompression with transforaminal interbody fusion for thoracic myelopathy due to ossification of the posterior longitudinal ligament and the ligamentum flavum at the same level.  

PubMed

Our objective was to evaluate the clinical efficacy and feasibility of posterior decompression with transforaminal thoracic interbody fusion (PTTIF) for thoracic myelopathy caused by ossification of the ligamentum flavum (OLF) and ossification of the posterior longitudinal ligament (OPLL) at the same level. Between March 2004 and December 2008, 13 patients (five men and eight women, average age: 56years, range: 39-72years) who underwent PTTIF for concurrent OLF and OPLL were studied retrospectively. The clinical efficacy, operative time, blood loss, sagittal alignment and complications were investigated. Cerebrospinal fluid leakage occurred in three patients, all of whom healed well after repair. One patient developed a urinary tract infection and one developed a wound infection, but both were cured with appropriate antibiotic therapy. Neurological symptom deterioration occurred in one patient, but she returned to her preoperative baseline after completing methylprednisolone therapy. After an average 36.8months follow up, the mean Japanese Orthopaedic Association (JOA) score significantly increased from 4.3±1.3 preoperatively to 7.2±1.8 at 3months after the operation and 8.5±1.7 at the final follow-up (P<0.01), with an overall recovery rate of 63.2±21.8%. Postoperative imaging demonstrated an improvement in the local kyphosis (P<0.01), and as of the final follow up no cases of spinal instability or instrument loosening had occurred. We conclude that PTTIF provides satisfactory neurological recovery and stabilises the thoracic fusion through a single posterior approach. However, this procedure is not complication free and demands advanced technical expertise on the part of practitioners, particularly to avoid catastrophic spinal cord injuries. PMID:23313526

Liu, Fa-Jing; Chai, Yi; Shen, Yong; Xu, Jia-Xin; Du, Wei; Zhang, Peng

2013-04-01

133

The Memory Metal Spinal System in a Posterior Lumbar Interbody Fusion (PLIF) Procedure: A Prospective, Non-Comparative Study to Evaluate the Safety and Performance  

PubMed Central

Study Design: A prospective, non-comparative study of 27 patients to evaluate the safety and performance of the Memory Metal Spinal System used in a PLIF procedure in the treatment of spondylolisthesis, symptomatic spinal stenosis or degenerative disc disease (DDD). Objective: To evaluate the clinical performance, radiological outcome and safety of the Memory Metal Spinal System, used in a PLIF procedure, in the treatment of spondylolisthesis, symptomatic spinal stenosis or degenerative disc disease in human subjects. Summary of Background Data: Spinal systems that are currently available for correction of spinal deformities or degeneration such as lumbar spondylosis or degenerative disc disease, use components manufactured from stainless steel or titanium and typically comprise two spinal rods with associated connection devices. The Memory Metal Spinal System consists of a single square spinal rod made from a nickel titanium alloy (Nitinol) used in conjunction with connection devices. Nitinol is characterized by its shape memory effect and is a more flexible material than either stainless steel or titanium. With current systems there is loss of achieved reposition due to the elastic properties of the spine. By using a memory metal in this new system the expectation was that this loss of reposition would be overcome due to the metal’s inherent shape memory properties. Furthermore, we expect a higher fusion rate because of the elastic properties of the memory metal. Methods: Twenty-seven subjects with primary diagnosis of spondylolisthesis, symptomatic spinal stenosis or degenerative disc disease (DDD) were treated with the Memory Metal Spinal System in conjunction with the Brantigan IF® Cage in two consecutive years. Clinical performance of the device was evaluated over 2 years using the Oswestry Disability Index (ODI), Short Form 36 questionnaire (SF-36) and pain visual analogue scale (VAS) scores. Safety was studied by collection of adverse events intra-operative and during the followup. Interbody fusion status was assessed using radiographs and a CT scan. Results: The mean pre-operative ODI score of 40.9 (±14.52) significantly improved to 17.7 (±16.76) at 24 months postoperative. Significant improvement in the physical component from the SF36 questionnaire was observed with increases from the baseline result of 42.4 to 72.7 at 24 months (p<.0001); The emotional component in the SF36 questionnaires mean scores highlighted a borderline significant increase from 56.5 to 81.7 at 24 months (p=0.0441). The average level of leg pain was reduced by more than 50% postoperation (VAS values reduced from 5.7 (±2.45) to 2.2 (±2.76) at 24 month post-operation with similar results observed for back pain. CT indicated interbody fusion rate was not significantly faster compared to other devices in literature. No device related adverse events were recorded in this study. Conclusions: The Memory Metal Spinal System, different from other devices on the market with regard to material and the one rod configuration, is safe and performed very well by improving clinically important outcomes in the treatment of spondylolisthesis, symptomatic spinal stenosis or degenerative disc disease. In addition the data compares favorably to that previously reported for other devices in the literature.

Kok, D; Grevitt, M; Wapstra, FH; Veldhuizen, AG

2012-01-01

134

Effect of alendronate on bone ingrowth into porous tantalum and carbon fiber interbody devices: an experimental study on spinal fusion in pigs.  

PubMed

Recent studies have reported that bisphosphonates reduce the resorption of grafted bone and inhibit bone resorption at a bone-implant interface. However, it is not known whether bisphosphonates affect bone ingrowth into porous biomaterial or spine fusion interbody devices with an autograft. In this study, 18 pigs (9 in each group) underwent anterior intervertebral lumbar arthrodeses at L2-3, L4-5 and L6-7. Each level was randomly allocated to one of the 3 implants: a solid piece of porous tantalum (Hedrocel), a porous tantalum ring or a carbon fiber cage both packed with an autograft. Alendronate was given orally to one of the groups. The radiographic and histological findings in the two groups 3 months after operation were similar in these devices. Histological examination showed that the original graft was entirely replaced by new trabecular bone in both groups. On histomorphometric analysis, the bone volume fraction, both inside the central hole of porous tantalum ring and in the porous tantalum, was larger in the pigs given alendronate than in the controls, but the fraction inside and around the central hole of the carbon fiber cage was not affected by this treatment. Short-term alendronate treatment, in a relatively low dose, does not impair the formation of new bone, but increases bone ingrowth into the central hole of the porous tantalum ring and the pores of the porous tantalum in this porcine model. This may be an effective way to enhance early biologic fixation of porous intervertebral implants. PMID:14620983

Zou, Xuenong; Xue, Qingyun; Li, Haisheng; Bünger, Mathias; Lind, Martin; Bünge, Cody

2003-10-01

135

Minimally Invasive Versus Open Transforaminal Lumbar Interbody Fusion for Degenerative Spondylolisthesis Grades 1-2: Patient-Reported Clinical Outcomes and Cost-Utility Analysis  

PubMed Central

Background Transforaminal lumbar interbody fusion (TLIF) is the standard surgical treatment for patients with lumbar degenerative spondylolisthesis who do not respond to a 6-week course of conservative therapy. A number of morbidities are associated with the conventional open-TLIF method, so minimally invasive surgery (MIS) techniques for TLIF (MIS-TLIF) have been introduced to reduce the trauma to paraspinal muscles and hasten postoperative recovery. Because providing cost-effective medical treatment is a core initiative of healthcare reforms, a comparison of open-TLIF and MIS-TLIF must include a cost-utility analysis in addition to an analysis of clinical effectiveness. Methods We compared patient-reported clinical functional outcomes and hospital direct costs in age-matched patients treated surgically with either open-TLIF or MIS-TLIF. Patients were followed for at least 1 year, and patient scores on the Oswestry Disability Index (ODI) and visual analog scale (VAS) were analyzed at 6 weeks, 6 months, and ?1 year postoperatively in the 2 treatment groups. Results Compared to their preoperative scores, patients in both the open-TLIF and MIS-TLIF groups had significant improvements in the ODI and VAS scores at each follow-up point, but no significant difference in functional outcome occurred between the open-TLIF and MIS-TLIF groups (P=0.46). However, open-TLIF is significantly more costly compared to MIS-TLIF (P=0.0002). Conclusion MIS-TLIF is a more cost-effective treatment than open-TLIF for patients with degenerative spondylolisthesis and is equally effective as the conventional open-TLIF procedure, although further financial analysis—including an analysis of indirect costs—is needed to better understand the full benefit of MIS-TLIF.

Sulaiman, Wale A. R.; Singh, Manish

2014-01-01

136

Harvesting local cylinder autograft from adjacent vertebral body for anterior lumbar interbody fusion: surgical technique, operative feasibility and preliminary clinical results  

PubMed Central

Autogenous iliac crest has long served as the gold standard for anterior lumbar arthrodesis although added morbidity results from the bone graft harvest. Therefore, femoral ring allograft, or cages, have been used to decrease the morbidity of iliac crest bone harvesting. More recently, an experimental study in the animal showed that harvesting local bone from the anterior vertebral body and replacing the void by a radio-opaque ?-tricalcium phosphate plug was a valid concept. However, such a concept precludes theoretically the use of posterior pedicle screw fixation. At one institution a consecutive series of 21 patients underwent single- or multiple-level circumferential lumbar fusion with anterior cages and posterior pedicle screws. All cages were filled with cancellous bone harvested from the adjacent vertebral body, and the vertebral body defect was filled with a ?-tricalcium phosphate plug. The indications for surgery were failed conservative treatment of a lumbar degenerative disc disease or spondylolisthesis. The purpose of this study, therefore, was to report on the surgical technique, operative feasibility, safety, benefits, and drawbacks of this technique with our primary clinical experience. An independent researcher reviewed all data that had been collected prospectively from the onset of the study. The average age of the patients was 39.9 (26–57) years. Bone grafts were successfully harvested from 28 vertebral bodies in all but one patient whose anterior procedure was aborted due to difficulty in freeing the left common iliac vein. This case was converted to a transforaminal interbody fusion (TLIF). There was no major vascular injury. Blood loss of the anterior procedure averaged 250 ml (50–350 ml). One tricalcium phosphate bone plug was broken during its insertion, and one endplate was broken because of wrong surgical technique, which did not affect the final outcome. One patient had a right lumbar plexopathy that was not related to this special technique. There was no retrograde ejaculation, infection or pseudoarthrosis. One patient experienced a deep venous thrombosis. At the last follow up (mean 28 months) all patients had a solid lumbar spine fusion. At the 6-month follow up, the pain as assessed on the visual analog scale (VAS) decreased from 6.9 to 4.5 (33% decrease), and the Oswestry disability index (ODI) reduced from 48.0 to 31.7 with a 34% reduction. However, at 2 years follow up there was a trend for increase in the ODI (35) and VAS (5). The data in this study suggest that harvesting a cylinder of autograft from the adjacent vertebral body is safe and efficient. Filling of the void defect with a ?-tricalcium phosphate plug does not preclude the use of posterior pedicle screw stabilization.

Jiang, Liang; Steffen, Thomas; Ouellet, Jean; Reindl, Rudy; Aebi, Max

2006-01-01

137

The accuracy of 3D image navigation with a cutaneously fixed dynamic reference frame in minimally invasive transforaminal lumbar interbody fusion.  

PubMed

Objective: In contrast to preoperative image-based 3D navigation systems, which require surgeon-dependent registration, an intraoperative cone-beam computed tomography (cb-CT) image-based 3D navigation system allows automatic registration during the acquisition of 3D images intraoperatively. Thus, the need for spinal exposure for point matching is obviated, making a cb-CT image-based navigation system ideal for use in minimally invasive spinal procedures. Conventionally, the dynamic reference frame (DRF) is mounted to an adjacent spinous process or iliac bone through a separate incision. However, the close proximity of the DRF to the surgical area may result in its interfering with the surgical procedure or causing streak artifacts on the navigation images. Cutaneous placement of the DRF overlying the sacral hiatus is one possible solution to these problems, but such a placement does not provide a solid bony fixation point and is distant from the surgical area, both of which factors may hinder the accuracy of the navigation. The purpose of this study was to evaluate the accuracy of a novel idea for DRF placement in a series of mini-open transforaminal lumbar interbody fusion (TLIF) procedures performed with intraoperative cb-CT image-based 3D navigation. Methods: From June 2009 to December 2009, 20 patients underwent mini-open TLIF for a total 82 pedicle screws placed in the lumbar spine with cutaneous placement of the DRF overlying the sacral hiatus. The pedicle screws were inserted under navigational guidance using cb-CT data acquired intraoperatively with a Medtronic O-arm. Screw positions were subsequently checked with a final intraoperative cb-CT scan. Nineteen patients underwent single-level fusion (8 at L4-5, 6 at L5-S1, 4 at L3-4, and 1 at L2-3) and one patient underwent two-level fusion (from L3-5). Results: There were 4 (4.9%) pedicle perforations greater than 2?mm out of the 82 pedicle screw insertions in the 20 patients. Two of these breached screws were repositioned and confirmed to be in place with a final intraoperative cb-CT. There were no complications of neural injury associated with these perforations. Conclusion: A cutaneously mounted DRF overlying the sacral hiatus provides accuracy in intraoperative 3D image guided navigation for mini-open TLIF that is comparable to that obtained in other reported series using a fixed bony attachment point for the DRF. PMID:23098190

Cho, Ji Young; Chan, Chee Keong; Lee, Sang-Ho; Lee, Ho-Yeon

2012-01-01

138

The Significance of Removing Ruptured Intervertebral Discs for Interbody Fusion in Treating Thoracic or Lumbar Type B and C Spinal Injuries through a One-Stage Posterior Approach  

PubMed Central

Objectives To identify the negative effect on treatment results of reserving damaged intervertebral discs when treating type B and type C spinal fracture-dislocations through a one-stage posterior approach. Methods This is a retrospective review of 53 consecutive patients who were treated in our spine surgery center from January 2005 to May 2012 due to severe thoracolumbar spinal fracture-dislocation. The patients in Group A (24 patients) underwent long-segment instrumentation laminectomy with pedicle screw-rod fixators for neural decompression. In Group B (29 patients), the patients underwent long-segment instrumentation laminectomy with pedicle screw-rod fixators for neural decompression evacuating of the ruptured disc and inserting of a bone graft into the evacuated disc space for interbody fusion. The mean time between injury and operation was 4.1 days (range 2–15 days). The clinical, radiologic and complication outcomes were analyzed retrospectively. Results Periodic follow-ups were carried out until an affirmative union or treatment failure took place. A progressive kyphosis angle larger than 10°, loss of disc height, pseudoarthrosis, recurrence of dislocation or subluxation, or instrument failure before fusion were considered treatment failures. Treatment failures were detected in 13 cases in Group A (failure rate was 54.2%). In Group B, there were 28 cases in which definitive bone fusion was demonstrated on CT scans, and CT scans of the other cases demonstrated undefined pseudoarthrosis without hardware failure. There were statistically significant differences between the two groups (p<0.001 chi-square test). The neurologic recoveries, assessed by the ASIA scoring system, were not satisfactory for the neural deficit patients in either group, indicating there was no significant difference with regard to neurologic recovery between the two groups (p>0.05 Fisher's exact test). Conclusion Intervertebral disc damage is a common characteristic in type B and C spinal fracture-dislocation injuries. The damaged intervertebral disc should be removed and substituted with a bone graft because reserving the damaged disc in situ increases the risk of treatment failure.

Zhang, Qian-Shi; Lu, Guo-Hua; Wang, Xiao-Bin; Li, Jing

2014-01-01

139

The influence of different magnitudes and methods of applying preload on fusion and disc replacement constructs in the lumbar spine: a finite element analysis.  

PubMed

In a finite element (FE) analysis of the lumbar spine, different preload application methods that are used in biomechanical studies may yield diverging results. To investigate how the biomechanical behaviour of a spinal implant is affected by the method of applying the preload, hybrid-controlled FE analysis was used to evaluate the biomechanical behaviour of the lumbar spine under different preload application methods. The FE models of anterior lumbar interbody fusion (ALIF) and artificial disc replacement (ADR) were tested under three different loading conditions: a 150 N pressure preload (PP) and 150 and 400 N follower loads (FLs). This study analysed the resulting range of motion (ROM), facet contact force (FCF), inlay contact pressure (ICP) and stress distribution of adjacent discs. The FE results indicated that the ROM of both surgical constructs was related to the preload application method and magnitude; differences in the ROM were within 7% for the ALIF model and 32% for the ADR model. Following the application of the FL and after increasing the FL magnitude, the FCF of the ADR model gradually increased, reaching 45% at the implanted level in torsion. The maximum ICP gradually decreased by 34.1% in torsion and 28.4% in lateral bending. This study concluded that the preload magnitude and application method affect the biomechanical behaviour of the lumbar spine. For the ADR, remarkable alteration was observed while increasing the FL magnitude, particularly in the ROM, FCF and ICP. However, for the ALIF, PP and FL methods had no remarkable alteration in terms of ROM and adjacent disc stress. PMID:22224913

Zhong, Zheng-Cheng; Hung, Chinghua; Lin, Hung-Ming; Wang, Ying-Hui; Huang, Chang-Hung; Chen, Chen-Sheng

2013-01-01

140

Clinical and radiographic assessment of transforaminal lumbar interbody fusion using HEALOS collagen-hydroxyapatite sponge with autologous bone marrow aspirate  

Microsoft Academic Search

Background contextStudies have suggested that the use of bone marrow aspirate (BMA) with HEALOS (DePuy Spine, Raynham, MA), a collagen-hydroxyapatite sponge (CHS), is an effective substitute for autologous iliac crest bone graft when used in fusion procedures of the lumbar spine.

Jason D. Carter; Alan B. Swearingen; Christopher D. Chaput; Mark D. Rahm

2009-01-01

141

Biomechanical comparison of unilateral and bilateral pedicle screws fixation for transforaminal lumbar interbody fusion after decompressive surgery -- a finite element analysis  

PubMed Central

Background Little is known about the biomechanical effectiveness of transforaminal lumbar interbody fusion (TLIF) cages in different positioning and various posterior implants used after decompressive surgery. The use of the various implants will induce the kinematic and mechanical changes in range of motion (ROM) and stresses at the surgical and adjacent segments. Unilateral pedicle screw with or without supplementary facet screw fixation in the minimally invasive TLIF procedure has not been ascertained to provide adequate stability without the need to expose on the contralateral side. This study used finite element (FE) models to investigate biomechanical differences in ROM and stress on the neighboring structures after TLIF cages insertion in conjunction with posterior fixation. Methods A validated finite-element (FE) model of L1-S1 was established to implant three types of cages (TLIF with a single moon-shaped cage in the anterior or middle portion of vertebral bodies, and TLIF with a left diagonally placed ogival-shaped cage) from the left L4-5 level after unilateral decompressive surgery. Further, the effects of unilateral versus bilateral pedicle screw fixation (UPSF vs. BPSF) in each TLIF cage model was compared to analyze parameters, including stresses and ROM on the neighboring annulus, cage-vertebral interface and pedicle screws. Results All the TLIF cages positioned with BPSF showed similar ROM (<5%) at surgical and adjacent levels, except TLIF with an anterior cage in flexion (61% lower) and TLIF with a left diagonal cage in left lateral bending (33% lower) at surgical level. On the other hand, the TLIF cage models with left UPSF showed varying changes of ROM and annulus stress in extension, right lateral bending and right axial rotation at surgical level. In particular, the TLIF model with a diagonal cage, UPSF, and contralateral facet screw fixation stabilize segmental motion of the surgical level mostly in extension and contralaterally axial rotation. Prominent stress shielded to the contralateral annulus, cage-vertebral interface, and pedicle screw at surgical level. A supplementary facet screw fixation shared stresses around the neighboring tissues and revealed similar ROM and stress patterns to those models with BPSF. Conclusions TLIF surgery is not favored for asymmetrical positioning of a diagonal cage and UPSF used in contralateral axial rotation or lateral bending. Supplementation of a contralateral facet screw is recommended for the TLIF construct.

2012-01-01

142

Cervical vertebral interbody fusion in the horse: a comparative study of bovine xenografts and autografts supported by stainless steel baskets.  

PubMed

A modified form of the Cloward technique for anterior cervical fusion in human beings was used in the application of different grafts for evaluation of their effectiveness in stabilizing equine cervical vertebrae. Results of bovine xenograft implants in 8 horses were compared with results of stainless steel baskets (SSB) packed with cancellous autogenous bone in 8 horses. Graft material was incorporated in all cases. Evidence of graft rejection was not present. Both forms of implants decreased the mobility of the intervertebral space in which they were implanted. A fibrous connective tissue union was prevalent after xenograft implantation. Osseous union was prevalent after implantation of the SSB. Reduction in range of motion was greatest at those sites with the SSB. PMID:6367560

DeBowes, R M; Grant, B D; Bagby, G W; Gallina, A M; Sande, R D; Ratzlaff, M H

1984-01-01

143

Medical i2b2 NLP Smoking Challenge: The A-Life System Architecture and Methodology  

PubMed Central

We describe the architecture of LifeCode® (A-Life Medical, Inc.), a natural language processing system for free-text clinical information extraction, our methodology in applying LifeCode® to the i2b2 smoking challenge, and statistical measures for performance evaluation. Due to the limited test size and the coefficient of variation in the test standard, it is difficult to draw conclusions regarding the relative efficacy of approaches that were applied to this challenge.

Heinze, Daniel T.; Morsch, Mark L.; Potter, Brian C.; Sheffer, Ronald E.

2008-01-01

144

Extreme Lateral Interbody Fusion Procedure  

MedlinePLUS Videos and Cool Tools

... is the assistant professor of neurosurgery at the University of South Florida College of Medicine. He will ... colleagues, chief of the spine section at the University of South Florida in Tampa, Florida. My name ...

145

Biomechanics of Lateral Interbody Spacers: Going Wider for Going Stiffer  

PubMed Central

This study investigates the biomechanical stability of a large interbody spacer inserted by a lateral approach and compares the biomechanical differences with the more conventional transforaminal interbody fusion (TLIF), with and without supplemental pedicle screw (PS) fixation. Twenty-four L2-L3 functional spinal units (FSUs) were tested with three interbody cage options: (i) 18?mm XLIF cage, (ii) 26?mm XLIF cage, and (iii) 11?mm TLIF cage. Each spacer was tested without supplemental fixation, and with unilateral and bilateral PS fixation. Specimens were subjected to multidirectional nondestructive flexibility tests to 7.5?N·m. The range of motion (ROM) differences were first examined within the same group (per cage) using repeated-measures ANOVA, and then compared between cage groups. The 26?mm XLIF cage provided greater stability than the 18?mm XLIF cage with unilateral PS and 11?mm TLIF cage with bilateral PS. The 18?mm XLIF cage with unilateral PS provided greater stability than the 11?mm TLIF cage with bilateral PS. This study suggests that wider lateral spacers are biomechanically stable and offer the option to be used with less or even no supplemental fixation for interbody lumbar fusion.

Pimenta, Luiz; Turner, Alexander W. L.; Dooley, Zachary A.; Parikh, Rachit D.; Peterson, Mark D.

2012-01-01

146

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

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 trial in which the silicon nitride cage is compared with the PEEK cage in patients with symptomatic degenerative lumbar disc disorders. Trial registration NCT01557829

2014-01-01

147

Anterior Lumbar Interbody Implants: Importance of the Interdevice Distance  

PubMed Central

Object. The implantation of interbody fusion cages allows for the restoration of disc height and the enlargement of the neuroforaminal space. The purpose of this study was to compare the extent of subsidence occurring after conventional cage placement compared to a novel wider cage placement technique. Methods. This study is a retrospective evaluation of radiographs of patients who underwent stand-alone single level anterior lumbar interbody fusion with lordotic titanium cages and rhBMP-2. Fifty-three patients were evaluated: 39 patients had wide cage placement (6?mm interdevice distance) and 14 had narrow cage placement (2?mm interdevice distance). Anterior and posterior intervertebral disc space heights were measured post-operatively and at follow-up imaging. Results. The decrease in anterior intervertebral disc space height was 2.05?mm versus 3.92?mm (P < .005) and 1.08?mm versus 3.06?mm in posterior disc space height for the wide cage placement and the narrow cage placement respectively. The proportion of patients with subsidence greater than 2?mm was 41.0% in the wide cage patients and 85.7% for the narrow cage patients (P < .005). Conclusions. The wider cage placement significantly reduced the amount of subsidence while allowing for a greater exposed surface area for interbody fusion.

Subach, Brian R.; Copay, Anne G.; Martin, Marcus M.; Schuler, Thomas C.

2011-01-01

148

Compressive strength of interbody cages in the lumbar spine: the effect of cage shape, posterior instrumentation and bone density  

Microsoft Academic Search

One goal of interbody fusion is to increase the height of the degenerated disc space. Interbody cages in particular have\\u000a been promoted with the claim that they can maintain the disc space better than other methods. There are many factors that\\u000a can affect the disc height maintenance, including graft or cage design, the quality of the surrounding bone and the

B. Jost; P. A. Cripton; T. Lund; T. R. Oxland; K. Lippuner; P. Jaeger; L.-P. Nolte

1998-01-01

149

Spine interbody implants: material selection and modification, functionalization and bioactivation of surfaces to improve osseointegration.  

PubMed

The clinical outcome of lumbar spinal fusion is correlated with achievement of bony fusion. Improving interbody implant bone on-growth and in-growth may enhance fusion, limiting pseudoarthrosis, stress shielding, subsidence and implant failure. Polyetheretherketone (PEEK) and titanium (Ti) are commonly selected for interbody spacer construction. Although these materials have desirable biocompatibility and mechanical properties, they require further modification to support osseointegration. Reports of extensive research on this topic are available in biomaterial-centric published reports; however, there are few clinical studies concerning surface modification of interbody spinal implants. The current article focuses on surface modifications aimed at fostering osseointegration from a clinician's point of view. Surface modification of Ti by creating rougher surfaces, modifying its surface topography (macro and nano), physical and chemical treatment and creating a porous material with high interconnectivity can improve its osseointegrative potential and bioactivity. Coating the surface with osteoconductive materials like hydroxyapatite (HA) can improve osseointegration. Because PEEK spacers are relatively inert, creating a composite by adding Ti or osteoconductive materials like HA can improve osseointegration. In addition, PEEK may be coated with Ti, effectively bio-activating the coating. PMID:24890288

Rao, Prashanth J; Pelletier, Matthew H; Walsh, William R; Mobbs, Ralph J

2014-05-01

150

Lumbar Laminectomy and Transforaminal Lumbar Interbody Fusion  

MedlinePLUS Videos and Cool Tools

... ANNOUNCER: During the next hour in a real-time Internet broadcast, spine specialists at Thomas Jefferson University ... in the program by sending questions at any time; just click the MDirectAccess button on the screen. ...

151

Lateral Transpsoas Fusion: Indications and Outcomes  

PubMed Central

Spinal fusion historically has been used extensively, and, recently, the lateral transpsoas approach to the thoracic and lumbar spine has become an increasingly common method to achieve fusion. Recent literature on this approach has elucidated its advantage over more traditional anterior and posterior approaches, which include a smaller tissue dissection, potentially lower blood loss, no need for an access surgeon, and a shorter hospital stay. Indications for the procedure have now expanded to include degenerative disc disease, spinal stenosis, degenerative scoliosis, nonunion, trauma, infection, and low-grade spondylolisthesis. Lateral interbody fusion has a similar if not lower rate of complications compared to traditional anterior and posterior approaches to interbody fusion. However, lateral interbody fusion has unique complications that include transient neurologic symptoms, motor deficits, and neural injuries that range from 1 to 60% in the literature. Additional studies are required to further evaluate and monitor the short- and long-term safety, efficacy, outcomes, and complications of lateral transpsoas procedures.

Patel, Vishal C.; Park, Daniel K.; Herkowitz, Harry N.

2012-01-01

152

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

PubMed Central

Purpose The aim of this study was to investigate the biomechanical stability provided by a novel, polylactic acid/nano-sized, ?-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.

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

2012-01-01

153

ALIFE@Work: a randomised controlled trial of a distance counselling lifestyle programme for weight control among an overweight working population [ISRCTN04265725  

Microsoft Academic Search

BACKGROUND: The prevalence of overweight is increasing and its consequences will cause a major public health burden in the near future. Cost-effective interventions for weight control among the general population are therefore needed. The ALIFE@Work study is investigating a novel lifestyle intervention, aimed at the working population, with individual counselling through either phone or e-mail. This article describes the design

Marieke F van Wier; Geertje AM Ariëns; Johanna C Dekkers; Ingrid JM Hendriksen; Nico P Pronk; Tjabe Smid; Willem van Mechelen

2006-01-01

154

Construct Rigidity after Fatigue Loading in Pedicle Subtraction Osteotomy with or without Adjacent Interbody Structural Cages.  

PubMed

Introduction?Studies document rod fracture in pedicle subtraction osteotomy (PSO) settings where disk spaces were preserved above or adjacent to the PSO. This study compares the multidirectional bending rigidity and fatigue life of PSO segments with or without interbody support. Methods?Twelve specimens received bilateral T12-S1 posterior fixation and L3 PSO. Six received extreme lateral interbody fusion (XLIF) cages in addition to PSO at L2-L3 and L3-L4; six had PSO only. Flexion-extension, lateral bending, and axial rotation (AR) tests were conducted up to 7.5 Newton-meters (Nm) for groups: (1) posterior fixation, (2) L3 PSO, (3) addition of cages (six specimens). Relative motion across the osteotomy (L2-L4) and entire fixation site (T12-S1) was measured. All specimens were then fatigue tested for 35K cycles. Results?Regardingmultiaxial bending, there was a significant 25.7% reduction in AR range of motion across L2-L4 following addition of cages. Regarding fatigue bending, dynamic stiffness, though not significant (p?=?0.095), was 22.2% greater in the PSO?+?XLIF group than in the PSO-only group. Conclusions?Results suggest that placement of interbody cages in PSO settings has a potential stabilizing effect, which is modestly evident in the acute setting. Inserting cages in a second-stage surgery remains a viable option and may benefit patients in terms of recovery but additional clinical studies are necessary to confirm this. PMID:24353970

Deviren, Vedat; Tang, Jessica A; Scheer, Justin K; Buckley, Jenni M; Pekmezci, Murat; McClellan, R Trigg; Ames, Christopher P

2012-12-01

155

Construct Rigidity after Fatigue Loading in Pedicle Subtraction Osteotomy with or without Adjacent Interbody Structural Cages  

PubMed Central

Introduction?Studies document rod fracture in pedicle subtraction osteotomy (PSO) settings where disk spaces were preserved above or adjacent to the PSO. This study compares the multidirectional bending rigidity and fatigue life of PSO segments with or without interbody support. Methods?Twelve specimens received bilateral T12–S1 posterior fixation and L3 PSO. Six received extreme lateral interbody fusion (XLIF) cages in addition to PSO at L2–L3 and L3–L4; six had PSO only. Flexion-extension, lateral bending, and axial rotation (AR) tests were conducted up to 7.5 Newton-meters (Nm) for groups: (1) posterior fixation, (2) L3 PSO, (3) addition of cages (six specimens). Relative motion across the osteotomy (L2–L4) and entire fixation site (T12–S1) was measured. All specimens were then fatigue tested for 35K cycles. Results?Regardingmultiaxial bending, there was a significant 25.7% reduction in AR range of motion across L2–L4 following addition of cages. Regarding fatigue bending, dynamic stiffness, though not significant (p?=?0.095), was 22.2% greater in the PSO?+?XLIF group than in the PSO-only group. Conclusions?Results suggest that placement of interbody cages in PSO settings has a potential stabilizing effect, which is modestly evident in the acute setting. Inserting cages in a second-stage surgery remains a viable option and may benefit patients in terms of recovery but additional clinical studies are necessary to confirm this.

Deviren, Vedat; Tang, Jessica A.; Scheer, Justin K.; Buckley, Jenni M.; Pekmezci, Murat; McClellan, R. Trigg; Ames, Christopher P.

2012-01-01

156

A radiological and cadaveric study of oblique lumbar interbody fixation in patients with normal spinal anatomy.  

PubMed

The purpose of this study was to determine whether it would be feasible to use oblique lumbar interbody fixation for patients with degenerative lumbar disease who required a fusion but did not have a spondylolisthesis. A series of CT digital images from 60 patients with abdominal disease were reconstructed in three dimensions (3D) using Mimics v10.01: a digital cylinder was superimposed on the reconstructed image to simulate the position of an interbody screw. The optimal entry point of the screw and measurements of its trajectory were recorded. Next, 26 cadaveric specimens were subjected to oblique lumbar interbody fixation on the basis of the measurements derived from the imaging studies. These were then compared with measurements derived directly from the cadaveric vertebrae. Our study suggested that it is easy to insert the screws for L1/2, L2/3 and L3/4 fixation: there was no significant difference in measurements between those of the 3-D digital images and the cadaveric specimens. For L4/5 fixation, part of L5 inferior articular process had to be removed to achieve the optimal trajectory of the screw. For L5/S1 fixation, the screw heads were blocked by iliac bone: consequently, the interior oblique angle of the cadaveric specimens was less than that seen in the 3D digital images. We suggest that CT scans should be carried out pre-operatively if this procedure is to be adopted in clinical practice. This will assist in determining the feasibility of the procedure and will provide accurate information to assist introduction of the screws. PMID:23814253

Wu, A M; Tian, N F; Wu, L J; He, W; Ni, W F; Wang, X Y; Xu, H Z; Chi, Y L

2013-07-01

157

Fusion  

NASA Astrophysics Data System (ADS)

Acknowledgments; 1. The invention of Dr Spitzer; 2. Behind closed doors; 3. Friends and rivals; 4. Searching for answers; 5. Dawn of the tokamak; 6. Building big science; 7. Forming the major league; 8. The political plasma; 9. The modern fusion lab; 10. The plasma olympics; 11. Different directions; 12. Struggling to sell fusion; 13. In sight of breakeven; 14. Fusion's past and future; Notes; Glossary; Appendices; Index.

Herman, Robin

2006-03-01

158

Fusion  

NASA Astrophysics Data System (ADS)

The book abounds with fascinating anecdotes about fusion's rocky path: the spurious claim by Argentine dictator Juan Peron in 1951 that his country had built a working fusion reactor, the rush by the United States to drop secrecy and publicize its fusion work as a propaganda offensive after the Russian success with Sputnik; the fortune Penthouse magazine publisher Bob Guccione sank into an unconventional fusion device, the skepticism that met an assertion by two University of Utah chemists in 1989 that they had created "cold fusion" in a bottle. Aimed at a general audience, the book describes the scientific basis of controlled fusion--the fusing of atomic nuclei, under conditions hotter than the sun, to release energy. Using personal recollections of scientists involved, it traces the history of this little-known international race that began during the Cold War in secret laboratories in the United States, Great Britain and the Soviet Union, and evolved into an astonishingly open collaboration between East and West.

Herman, Robin

1990-10-01

159

Bone graft gel: Autologous growth factors used with autograft bone for lumbar spine fusions  

Microsoft Academic Search

A method to combine autologous growth factors (AGF) with autologous bone graft in a bone graft gel for spine fusions is described.\\u000a The bone graft gel can be inserted into cages for interbody fusions or used directly for posterolateral intertransverse fusions.\\u000a Sixty patients have undergone spinal fusion surgery under this technique. No equipment problems have been encountered and\\u000a no adverse

Bikash Bose; Michael A. Balzarini

2002-01-01

160

Painful Schmorl's node treated by lumbar interbody fusion  

Microsoft Academic Search

Study design: A case report of painful lumbar Schmorl's node is presented.Objective: To describe diagnostic evidence and the result of surgical treatment of a rare case of painful Schmorl's node.Setting: Niigata, Japan.Case report: A 55-year-old housewife was diagnosed with painful Schmorl's node of L3 by discography, which depicted leakage of the contrast medium into the L3 vertebra through a disruption

K Hasegawa; A Ogose; T Morita; Y Hirata

2004-01-01

161

Biomechanical effects of polyaxial pedicle screw fixation on the lumbosacral segments with an anterior interbody cage support  

PubMed Central

Background Lumbosacral fusion is a relatively common procedure that is used in the management of an unstable spine. The anterior interbody cage has been involved to enhance the stability of a pedicle screw construct used at the lumbosacral junction. Biomechanical differences between polyaxial and monoaxial pedicle screws linked with various rod contours were investigated to analyze the respective effects on overall construct stiffness, cage strain, rod strain, and contact ratios at the vertebra-cage junction. Methods A synthetic model composed of two ultrahigh molecular weight polyethylene blocks was used with four titanium pedicle screws (two in each block) and two rods fixation to build the spinal construct along with an anterior interbody cage support. For each pair of the construct fixed with polyaxial or monoaxial screws, the linked rods were set at four configurations to simulate 0°, 7°, 14°, and 21° lordosis on the sagittal plane, and a compressive load of 300 N was applied. Strain gauges were attached to the posterior surface of the cage and to the central area of the left connecting rod. Also, the contact area between the block and the cage was measured using prescale Fuji super low pressure film for compression, flexion, lateral bending and torsion tests. Results Our main findings in the experiments with an anterior interbody cage support are as follows: 1) large segmental lordosis can decrease the stiffness of monoaxial pedicle screws constructs; 2) polyaxial screws rather than monoaxial screws combined with the cage fixation provide higher compression and flexion stiffness in 21° segmental lordosis; 3) polyaxial screws enhance the contact surface of the cage in 21° segmental lordosis. Conclusion Polyaxial screws system used in conjunction with anterior cage support yields higher contact ratio, compression and flexion stiffness of spinal constructs than monoaxial screws system does in the same model when the spinal segment is set at large lordotic angles. Polyaxial pedicle screw fixation performs nearly equal percentages of vertebra-cage contact among all constructs with different sagittal alignments, therefore enhances the stabilization effect of interbody cages in the lumbosacral area.

Chen, Shih-Hao; Mo Lin, Ruey; Chen, Hsiang-Ho; Tsai, Kai-Jow

2007-01-01

162

3:35 Demographic influences on the outcome of spinal fusion  

Microsoft Academic Search

Purpose of study: To analyze the outcome of spinal fusion with respect to both surgical and nonmedical variables.Methods used: The first 82 patients treated at our institution with a combined posterior lumbar interbody fusion\\/bilateral lateral fusion\\/pedicle screw instrumentation technique were retrospectively studied. Sixty-nine (84%) of the patients were located, with results evaluated by a structured telephone interview by an investigator

Stephen Faust; Thomas Ducker; David Hatef

2002-01-01

163

Surgical treatment of a hemivertebra by partial ventral corpectomy and fusion in a Labrador puppy.  

PubMed

This report describes a partial ventral verte-brectomy and interbody fusion for a progressive hemivertebra disease using a ventral transthoracic approach in a 3.6-month-old male Labrador puppy. The goal of this article is to clarify the potential advantages of this uncommon surgical technique for this condition and to discuss its technical aspects. PMID:20585711

Meheust, P; Robert, R

2010-01-01

164

Cost effectiveness of disc prosthesis versus lumbar fusion in patients with chronic low back pain: randomized controlled trial with 2-year follow-up  

Microsoft Academic Search

This randomized controlled health economic study assesses the cost-effectiveness of the concept of total disc replacement\\u000a (TDR) (Charité\\/Prodisc\\/Maverick) when compared with the concept of instrumented lumbar fusion (FUS) [posterior lumbar fusion\\u000a (PLF) \\/posterior lumbar interbody fusion (PLIF)]. Social and healthcare perspectives after 2 years are reported. In all, 152\\u000a patients were randomized to either TDR (n = 80) or lumbar FUS (n = 72). Cost

Peter Fritzell; Svante Berg; Fredrik Borgström; Tycho Tullberg; Hans Tropp

165

Hybrid construct for two levels disc disease in lumbar spine.  

PubMed

Prospective study. To study the validity of Hybrid construction (Anterior Lumbar Interbody Fusion) ALIF at one level and total disc arthroplasty (TDA) at adjacent, for two levels disc disease in lumbar spine as surgical strategy. With growing evidence that fusion constructs in the treatment of degenerative disc disease (DDD) may alter sagittal balance and contribute to undesirable complications in the long-term, total disc arthroplasty (TDA) slowly becomes an accepted treatment option for a selected group of patients. Despite encouraging early and intermediate term results of single-level total disc arthroplasty reported in the literature, there is growing evidence that two-level arthroplasty does not fare as well. Hybrid fusion is an attempt to address two-level DDD by combining the advantages of a single-level ALIF with those of a single-level arthroplasty. 42 patients (25 females and 17 males) underwent Hybrid fusion and had a median follow-up of 26.3 months. The primary functional outcomes were assessed before and after surgery with Oswestry Disability Index and the visual analogue score of the back and legs. Patients were divided into four groups according to the percentage improvement between preop and postop ODI scores. A total of 42 patients underwent a hybrid fusion as follows: 35 L5-S1 ALIF/L4-5 prosthesis, 3 L4-5 ALIF/L3-4 prosthesis, 2 L5-S1 ALIF/L4-5 prosthesis/L3-4 prosthesis, 1 L5-S1 prosthesis/L4-5 ALIF, and 1 L5-S1 ALIF/L4-5 ALIF/L3-4 prosthesis. At 2-years clinical outcomes, mean reduction in ODI is 24.9 points (53.0% improvement compared to preop ODI). The visual analogue score for the back is 64.6% improvement. At 2-year clinical outcomes, Hybrid fusion is a viable surgical alternative for the treatment of two-level DDD in comparison with two-level TDA and with two-level fusion. PMID:19888610

Aunoble, Stephane; Meyrat, Robert; Al Sawad, Yasser; Tournier, C; Leijssen, Philip; Le Huec, Jean-Charles

2010-02-01

166

Anterior cervical fusion with a bio-resorbable composite cage (beta TCP–PLLA): clinical and radiological results from a prospective study on 20 patients  

Microsoft Academic Search

A resorbable composite material (40% PLLA and 60% beta TCP) with a high breaking strength and capacity to withstand plastic\\u000a and elastic strain has been developed for cervical interbody fusion. This is a prospective study to evaluate clinical and\\u000a radiological results of 20 patients implanted with 27 cages (mean follow-up, 27 months). Clinical (neck disability index,\\u000a VAS, neurological evaluation) and radiological

F. Debusscher; S. Aunoble; Y. Alsawad; D. Clement; Jean-Charles Le Huec

2009-01-01

167

Transforaminal Lumbar Interbody Fusion Using a Modified Distractor Handle: A Midterm Clinicoradiological Follow-Up Study  

PubMed Central

In current TLIF practice, the choice of the cage size is empirical and primarily depends on the case volume and experience of the surgeon. We used a self-made modified distractor handle in TLIF procedure with the goal of standardizing the intervertebral space tension and determining the proper cage size.

Rewuti, Abuduaini; Chen, Zixian; Feng, Zhenzhou; Cao, Yuanwu; Jiang, Xiaoxing; Jiang, Chun

2013-01-01

168

Biomechanical effect of anterior cervical spine fusion on adjacent segments.  

PubMed

The biomechanical effects of superior (C4-C5) and inferior (C5-C6) level fusions with different graft materials on the adjacent unaltered components were quantified using an anatomically accurate and experimentally validated C4-C5-C6 finite element model. Smith-Robinson and Bailey-Badgley fusion procedures were analyzed with five different types of inter-body fusion materials with varying stiffnesses. Intact and surgically altered finite element models were subjected to physiologic compression, flexion, extension and lateral bending. The external axial and angular stiffness, and the internal unaltered intervertebral disc (C5-C6 for the superior and C4-C5 for inferior fusion) and C5 vertebral body stresses were determined. The superior level fusion resulted in the highest increase in external response in lateral bending for all implant materials in both surgical procedures. In contrast, the inferior level fusion produced a higher increase in the C4-C5 disc and C5 vertebral body stresses in compression than the superior level fusion in both surgical procedures. The increased internal stress responses reflecting the changes in the load-sharing following inferior level fusion may explain clinical observations such as enhanced degeneration subsequent to surgery. Because of the inclusion of three levels in the present multi-segment finite element model, it was possible to determine these responses in the unaltered adjacent components of the cervical spine. PMID:10436851

Maiman, D J; Kumaresan, S; Yoganandan, N; Pintar, F A

1999-01-01

169

Shape optimization for the subsidence resistance of an interbody device using simulation-based genetic algorithms and experimental validation.  

PubMed

Subsidence of interbody devices into the vertebral body might result in serious clinical problems, especially when the devices are not well designed and analyzed. Recently, some novel designs were proposed to reduce the risk of subsidence, but those designs are based on the researcher's experience. The purpose of this study was to discover the interbody device design with excellent subsidence resistance by changing the device's shape. The three-dimensional nonlinear finite element models, which consisted of the interbody device and vertebral body, were created first. Then, the simulation-based genetic algorithm, which combined the finite element model and the searching algorithm, was developed by using ANSYS® Parametric Design Language. Finally, the numerical results were carefully validated with the use of biomechanical tests. The optimum shape design obtained in this study looks like a flower with many petals and it has excellent subsidence resistance when compared with the other designs provided by the past studies. The results of the present study could help surgeons to understand the subsidence resistance of interbody devices in terms of their shapes and has directly provided the design rationales to engineers. PMID:23335363

Hsu, Ching-Chi

2013-07-01

170

Biomechanical comparison between lumbar disc arthroplasty and fusion.  

PubMed

The artificial disc is a mobile implant for degenerative disc replacement that attempts to lessen the degeneration of the adjacent elements. However, inconsistent biomechanical results for the neighboring elements have been reported in a number of studies. The present study used finite element (FE) analysis to explore the biomechanical differences at the surgical and both adjacent levels following artificial disc replacement and interbody fusion procedures. First, a three-dimensional FE model of a five-level lumbar spine was established by the commercially available medical imaging software Amira 3.1.1, and FE software ANSYS 9.0. After validating the five-level intact (INT) model with previous in vitro studies, the L3/L4 level of the INT model was modified to either insert an artificial disc (ProDisc II; ADR) or incorporate bilateral posterior lumbar interbody fusion (PLIF) cages with a pedicle screw fixation system. All models were constrained at the bottom of the L5 vertebra and subjected to 150N preload and 10Nm moments under four physiological motions. The ADR model demonstrated higher range of motion (ROM), annulus stress, and facet contact pressure at the surgical level compared to the non-modified INT model. At both adjacent levels, ROM and annulus stress were similar to that of the INT model and varied less than 7%. In addition, the greatest displacement of posterior annulus occurred at the superior-lateral region. Conversely, the PLIF model showed less ROM, less annulus stress, and no facet contact pressure at the surgical level compared to the INT model. The adjacent levels had obviously high ROM, annulus stress, and facet contact pressure, especially at the adjacent L2/3 level. In conclusion, the artificial disc replacement revealed no adjacent-level instability. However, instability was found at the surgical level, which might accelerate degeneration at the highly stressed annulus and facet joint. In contrast to disc replacement results, the posterior interbody fusion procedure revealed possibly accelerative degeneration of the annulus and facet joint at both adjacent levels. PMID:18760654

Chen, Shih-Hao; Zhong, Zheng-Cheng; Chen, Chen-Sheng; Chen, Wen-Jer; Hung, Chinghua

2009-03-01

171

Comparison of Expandable and Fixed Interbody Cages in a Human Cadaver Corpectomy Model: Fatigue Characteristics.  

PubMed

STUDY DESIGN:: In vitro cadaver biomechanics study. OBJECTIVE:: The goal of this study is to compare the in situ fatigue life of expandable versus fixed interbody cage designs. SUMMARY OF BACKGROUND DATA:: Expandable cages are becoming more popular due in large part to their versatility; however, subsidence and catastrophic failure remain a concern. This in vitro analysis investigates the fatigue life of expandable and fixed interbody cages in a single level human cadaver corpectomy model by evaluating modes of subsidence of expandable and fixed cages as well as change in stiffness of the constructs with cyclic loading. METHODS:: 19 specimens from ten human thoracolumbar spines (T10-L2, L3-L5) were biomechanically evaluated following a single level corpectomy that was reconstructed with an expandable or fixed cage and anterior dual rod instrumentation. All specimens underwent 98?K cycles to simulate 3 months of postoperative weight bearing. In addition, a third group with hyperlordotic cages was used to simulate catastrophic failure that is observed in clinical practice. RESULTS:: Three fixed and two expandable cages withstood the cyclic loading despite perfect sagittal and coronal plane fitting of the endcaps. The majority of the constructs settled in following initial subsidence. The catastrophic failures that were observed in clinical practice could not be reproduced with hyperlordotic cages. However, all cages in this group subsided, and 60% resulted in endplate fractures during deployment of the cage. CONCLUSIONS:: Despite greater surface contact area, expandable cages have a trend for higher subsidence rates when compared to fixed cages. When there is edge loading as in the hyperlordotic cage scenario, there is a higher risk of subsidence and intraoperative fracture during deployment of expandable cages. PMID:22925989

Pekmezci, Murat; Tang, Jessica Anne; Cheng, Liu; Modak, Ashin; McClellan, R Trigg; Buckley, Jenni M; Ames, Christopher P

2012-08-23

172

Extreme multi-level anterior cervical discectomy and fusion.  

PubMed

The use of anterior cervical discectomy and fusion (ACDF) is a common procedure used to treat those who suffer from degenerative disc disease (DDD) of the cervical spine which may result in spondylolisthesis, spinal stenosis, disc herniation, nerve root and/or cord compression. ACDF is regularly used for the fusion of one to four cervical spine levels; however, the literature documenting the fusion of 5 or 6 levels is surprisingly lacking. In this retrospective review of our case series, we document two 5-level and two 6-level ACDF in elderly patients using custom made titanium fusion plates and patellar allograft bone for interbody placement without posterior fixation. The documentation of these long anterior constructs without supplemental posterior fixation or the use of a halo vest apparatus, but a simple neck collar for three months, is an important contribution to the literature illustrating that with utilization of appropriate technique, a high number of levels can be safely fused in the elderly patients necessitating this particular procedure. PMID:23957113

Morgan, Jeremy P; Asfora, Wilson T

2013-07-01

173

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 4: Radiographic assessment of fusion status.  

PubMed

The ability to identify a successful arthrodesis is an essential element in the management of patients undergoing lumbar fusion procedures. The hypothetical gold standard of intraoperative exploration to identify, under direct observation, a solid arthrodesis is an impractical alternative. Therefore, radiographic assessment remains the most viable instrument to evaluate for a successful arthrodesis. Static radiographs, particularly in the presence of instrumentation, are not recommended. In the absence of spinal instrumentation, lack of motion on flexion-extension radiographs is highly suggestive of a successful fusion; however, motion observed at the treated levels does not necessarily predict pseudarthrosis. The degree of motion on dynamic views that would distinguish between a successful arthrodesis and pseudarthrosis has not been clearly defined. Computed tomography with fine-cut axial images and multiplanar views is recommended and appears to be the most sensitive for assessing fusion following instrumented posterolateral and anterior lumbar interbody fusions. For suspected symptomatic pseudarthrosis, a combination of techniques including static and dynamic radiographs as well as CT images is recommended as an option. Lack of facet fusion is considered to be more suggestive of a pseudarthrosis compared with absence of bridging posterolateral bone. Studies exploring additional noninvasive modalities of fusion assessment have demonstrated either poor potential, such as with (99m)Tc bone scans, or provide insufficient information to formulate a definitive recommendation. PMID:24980581

Choudhri, Tanvir F; Mummaneni, Praveen V; Dhall, Sanjay S; Eck, Jason C; Groff, Michael W; Ghogawala, Zoher; Watters, William C; Dailey, Andrew T; Resnick, Daniel K; Sharan, Alok; Wang, Jeffrey C; Kaiser, Michael G

2014-07-01

174

Fusion Basics  

NSDL National Science Digital Library

This website from the Princeton Plasma Physics Laboratory provides background information about fusion. Different sections cover fusion reactions, plasma heating, and how a fusion power plant would work. In addition, the site offers links to research projects at the Princeton Plasma Physics Laboratory.

2009-11-05

175

A meta-analysis of artificial total disc replacement versus fusion for lumbar degenerative disc disease  

PubMed Central

Lumbar fusion has been developed for several decades and became the standard surgical treatment for symptomatic lumbar degenerative disc disease (DDD). Artificial total disc replacement (TDR), as an alternative for spinal arthrodesis, is becoming more commonly employed treating lumbar DDD. It is still uncertain whether TDR is more effective and safer than lumbar fusion. To systematically compare the effectiveness and safety of TDR to that of the fusion for the treatment of lumbar DDD, we performed a meta-analysis. Cochrane review methods were used to analyze all relevant randomized controlled trials published up to July 2009. Five relevant randomized controlled trials involving 837 patients were identified. Patients in TDR group have sightly better functioning and less back or leg pain without clinical significance, and significantly higher satisfaction status in TDR group compared with lumbar fusion group at the 2-year follow-up. But these outcomes are highly influenced by the study with BAK cage interbody fusion, the function/pain and patient satisfaction status are no longer significantly different between two groups after excluding this study. At 5 years, these outcomes are not significantly different between comparing groups. The complication and reoperation rate of two groups are similar both at 2 and at 5 years. In conclusion, TDR does not show significant superiority for the treatment of lumbar DDD compared with fusion. The benefits of motion preservation and the long-term complications are still unable to be concluded. More high-quality RCTs with long-term follow-up are needed.

Yajun, Wu; Xiuxin, Han; Cui, Cui

2010-01-01

176

One-stage posterior C2 and C3 pedicle screw fixation or combined anterior C2-C3 fusion for the treatment of unstable hangman's fracture  

PubMed Central

The present study aimed to evaluate the effect of using one-stage posterior C2 and C3 pedicle screw fixation or combined anterior C2-C3 fusion in the treatment of unstable hangman’s fracture. A total of 13 patients with unstable hangman’s fractures underwent C2 and C3 pedicle screw fixation, lamina interbody fusion or combined anterior C2-C3 fusion and imaging examinations to evaluate the fracture fixation and healing condition at three days and three months following surgery. Postoperative X-ray and computed tomography (CT) results showed high fracture reduction, good internal fixation position and reliable fracture fixation. The three-month postoperative CT showed good vertebral fracture healing. C2 and C3 pedicle screw fixation has a good curative effect in the treatment of unstable hangman’s fracture. The direct fixation of the fracture enables early ambulation by the patients.

LIU, JINGCHEN; LI, YE; WU, YUNTAO

2013-01-01

177

Fusion breeder  

SciTech Connect

The fusion breeder is a fusion reactor designed with special blankets to maximize the transmutation by 14 MeV neutrons of uranium-238 to plutonium or thorium to uranium-233 for use as a fuel for fission reactors. Breeding fissile fuels has not been a goal of the US fusion energy program. This paper suggests it is time for a policy change to make the fusion breeder a goal of the US fusion program and the US nuclear energy program. The purpose of this paper is to suggest this policy change be made and tell why it should be made, and to outline specific research and development goals so that the fusion breeder will be developed in time to meet fissile fuel needs.

Moir, R.W.

1982-02-22

178

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 16: Bone graft extenders and substitutes as an adjunct for lumbar fusion.  

PubMed

In an attempt to enhance the potential to achieve a solid arthrodesis and avoid the morbidity of harvesting autologous iliac crest bone (AICB) for a lumbar fusion, numerous alternatives have been investigated. The use of these fusion adjuncts has become routine despite a lack of convincing evidence demonstrating a benefit to justify added costs or potential harm. Potential alternatives to AICB include locally harvested autograft, calcium-phosphate salts, demineralized bone matrix (DBM), and the family of bone morphogenetic proteins (BMPs). In particular, no option has created greater controversy than the BMPs. A significant increase in the number of publications, particularly with respect to the BMPs, has taken place since the release of the original guidelines. Both DBM and the calciumphosphate salts have demonstrated efficacy as a graft extender or as a substitute for AICB when combined with local autograft. The use of recombinant human BMP-2 (rhBMP-2) as a substitute for AICB, when performing an interbody lumbar fusion, is considered an option since similar outcomes have been observed; however, the potential for heterotopic bone formation is a concern. The use of rhBMP-2, when combined with calcium phosphates, as a substitute for AICB, or as an extender, when used with local autograft or AICB, is also considered an option as similar fusion rates and clinical outcomes have been observed. Surgeons electing to use BMPs should be aware of a growing body of literature demonstrating unique complications associated with the use of BMPs. PMID:24980593

Kaiser, Michael G; Groff, Michael W; Watters, William C; Ghogawala, Zoher; Mummaneni, Praveen V; Dailey, Andrew T; Choudhri, Tanvir F; Eck, Jason C; Sharan, Alok; Wang, Jeffrey C; Dhall, Sanjay S; Resnick, Daniel K

2014-07-01

179

Thoracoscopic assisted anterior fusion in fractures of the thoracic and lumbar spine  

Microsoft Academic Search

Summary\\u000a Objectives  Using a thoracoscopic approach reduction of vertebral body fractures and interbody fusion of the involved segment after implantation\\u000a of an autogenous bone graft and plate fixation.\\u000a \\u000a \\u000a \\u000a \\u000a Indications  Unstable fractures of the vertebral column from T4 to L3 inclusive of Types A1.2 and A1.3 of the AO classification. Fractures\\u000a of types A2, A3, B and C. Discoligamentous instability. Posttraumatic deformity.\\u000a \\u000a \\u000a \\u000a \\u000a Contraindications  Cardiopulmonary

Rudolf Beisse; Michael Potulski; Volker Biihren

1999-01-01

180

Laser fusion  

Microsoft Academic Search

Unrestricted laser fusion offers nations an opportunity to circumvent arms control agreements and develop thermonuclear weapons. Early laser weapons research sought a clean radiation-free bomb to replace the fission bomb, but this was deceptive because a fission bomb was needed to trigger the fusion reaction and additional radioactivity was induced by generating fast neutrons. As laser-implosion experiments focused on weapons

W. A. Smit; P. Boskma

1980-01-01

181

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

PubMed Central

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

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

2013-01-01

182

Pros, cons, and costs of INFUSE in spinal surgery  

PubMed Central

Background: INFUSE (recombinant human bone morphogenetic protein-2 [rh-BMP-2]; Medtronic, Memphis, TN, USA) is approved by the Federal Drug Administration (FDA) only for use with the lumbar tapered fusion device (LT Cage; Medtronic) to perform single-level anterior lumbar interbody fusions (ALIF: L2-S1 levels). INFUSE, however, is widely utilized in an “off-label” capacity for anterior and/or posterior cervical, thoracic, and lumbar surgery. Nevertheless, Medicare and other insurance companies, are now increasingly denying reimbursement (average cost of a “large” INFUSE to the hospital without overhead $5000-6000) to hospitals for INFUSE when utilized “off-label”. Methods: This commentary looks at several representative studies citing the cons associated with utilizing INFUSE in spinal surgery, contraindications, complications, and cost factors. Results: There are multiple cons of utilizing INFUSE in an “off-label” capacity for spinal surgery. Direct contraindications include pregnancy, allergy to titanium, allergy to bovine type I collagen or rhBMP-2, infection, tumor, liver or kidney disease, immunosuppression (e.g., lupus, HIV/AIDS); contraindications are also seen in those receiving radiation, chemotherapy, or steroids. Reported complications include exuberant/ectopic bone formation, paralysis (cord, nerve damage), dural tears, bowel–bladder and sexual dysfunction, respiratory failure, inflammation of adjacent tissues, fetal developmental complications, scar, excessive bleeding, and even death. Complications are so prevalent in the anterior cervical spine, that many surgeons no longer use it in this region. Similarly, INFUSE complications and indications for posterior lumbar interbody fusions (PLIFs) and transforaminal interbody lumbar fusions (TLIFs) should also be reexamined. Conclusions: More surgeons need to question the safety, efficacy, and appropriate “off-label” use of INFUSE in all spine surgeries.

Epstein, Nancy E.

2011-01-01

183

Fusion Power.  

ERIC Educational Resources Information Center

Discusses the extraordinary potential, the technical difficulties, and the financial problems that are associated with research and development of fusion power plants as a major source of energy. (GA)

Dingee, David A.

1979-01-01

184

Fusion Simulation  

NSDL National Science Digital Library

In this activity, kids are able to see with their own eyes how fusion works. The simple experiment requires only Velcro and two strong magnets.The activity begins with a brief overview that introduces students to the science they are about to see. Then, the procedure is laid out in simple step-by-step directions. The activity ends with an explanation that gives students a deeper understanding of how what they've just witnessed relates to fusion.

185

Pedicle-Screw-Based Dynamic Systems and Degenerative Lumbar Diseases: Biomechanical and Clinical Experiences of Dynamic Fusion with Isobar TTL  

PubMed Central

Dynamic systems in the lumbar spine are believed to reduce main fusion drawbacks such as pseudarthrosis, bone rarefaction, and mechanical failure. Compared to fusion achieved with rigid constructs, biomechanical studies underlined some advantages of dynamic instrumentation including increased load sharing between the instrumentation and interbody bone graft and stresses reduction at bone-to-screw interface. These advantages may result in increased fusion rates, limitation of bone rarefaction, and reduction of mechanical complications with the ultimate objective to reduce reoperations rates. However published clinical evidence for dynamic systems remains limited. In addition to providing biomechanical evaluation of a pedicle-screw-based dynamic system, the present study offers a long-term (average 10.2 years) insight view of the clinical outcomes of 18 patients treated by fusion with dynamic systems for degenerative lumbar spine diseases. The findings outline significant and stable symptoms relief, absence of implant-related complications, no revision surgery, and few adjacent segment degenerative changes. In spite of sample limitations, this is the first long-term report of outcomes of dynamic fusion that opens an interesting perspective for clinical outcomes of dynamic systems that need to be explored at larger scale.

Barrey, Cedric; Perrin, Gilles; Champain, Sabina

2013-01-01

186

Polarized fusion  

NASA Astrophysics Data System (ADS)

Since more than 50 years it has been discussed to increase the gain of nuclear fusion reactors with the use of polarized fuel. For example, the total cross sections of the fusion reactions d + t ? 4He + n or 3He + d ? 4He + p are increased by a factor of about 1.5 if the spins of both incoming particles are aligned. But before polarized fuel can be used for energy production in the different types of reactors, a number of questions must be answered. In this contribution we give an overview on our various activities in this field of research.

Engels, R.; Grigoryev, K.; Kochenda, L.; Kravtsov, P.; Mikirtytchiants, M.; Rathmann, F.; Paetz gen. Schieck, H.; Ströher, H.; Trofimov, V.; Vasilyev, A.; Vznuzdaev, M.

2014-01-01

187

Splenogonadal fusion.  

PubMed

We report a case of an 11-year-old boy who presented with a painless left scrotal mass of one year's duration. Clinical examination and diagnostic modalities indicated a solid left testicular mass. Exploration was done and a complete splenogonadal fusion was found. The ectopic splenic tissue was completely removed with preservation of the testis. Splenogonadal fusion is a rare and infrequently reported entity in the paediatric surgical literature. This was our first encounter with this condition. A review of the literature is briefly presented here. PMID:18924073

Alalayet, Y F; Mansoor, K; Shiba, N A; Khan, A M; Al Kasim, F

2008-10-01

188

Posterior fusion and implantation of the SOCON-SRI system in the treatment of adult spondylolisthesis.  

PubMed

Surgery for adult patients with lumbar and lumbosacral spondylolisthesis is reserved for those with intractable radiculopathy, claudication, or symptomatic spinal instability. Internal fixation, in which posterior fusion, transpedicular screw fixation, and implantation of titanium devices are performed, has been advocated to improve fusion rates and clinical results. Fourteen consecutive patients with Grade II to III lumbar and lumbosacral spondylolisthesis who underwent posterior decompression, reduction, autologous posterior facet joint arthrodesis, and SOCON-SRI implantation are retrospectively reviewed. All patients underwent complete preoperative clinical and neuroradiological evaluation. Treatment consisted of posterior decompressive surgery and implantation of the SOCON-SRI system (transpedicular screws, prebent longitudinal rods, and one locking-screw clamps). Distraction of the interbody space and rotation were performed to achieve an optimum spinal realignment. The facet joints were fused by using autologous bone graft. The authors obtained detailed clinical, functional, economic, and neuroradiological follow-up data for up to 14 months (range 8-18 months). The efficacy of the treatment was evaluated by comparing pre- and postoperative data. Pain was decreased in all cases, neurological dysfunction ameliorated in 50%, and functional and economic status was improved in 78% and 100%, respectively. No cases of fusion failure or instrumentation-related complications occurred. The authors describe their results of treating patients with spondylolisthesis in the light of the rationale for surgery and the more recent pertinent literature. PMID:16918204

La Rosa, G; Germano, A; Conti, A; Cacciola, F; Caruso, G; Tomasello, F

1999-12-15

189

Data fusion  

Microsoft Academic Search

The development of the Internet in recent years has made it possible and useful to access many different information systems anywhere in the world to obtain information. While there is much research on the integration of heterogeneous information systems, most commercial systems stop short of the actual integration of available data. Data fusion is the process of fusing multiple records

Jens Bleiholder; Felix Naumann

2008-01-01

190

Nuclear Fusion.  

National Technical Information Service (NTIS)

Fusion of very light (with only a couple of nucleons) and of heavier nuclei is discussed, respectively, as a source of nuclear energy and towards the extension of the periodic table to include superheavy elements. In particular, laser-induced nuclear fusi...

R. K. Gupta K. V. Subbaram

1978-01-01

191

Kinematic evaluation of the adjacent segments after lumbar instrumented surgery: a comparison between rigid fusion and dynamic non-fusion stabilization.  

PubMed

The aim of the current study was to evaluate changes in lumbar kinematics after lumbar monosegmental instrumented surgery with rigid fusion and dynamic non-fusion stabilization. A total of 77 lumbar spinal stenosis patients with L4 degenerative spondylolisthesis underwent L4-5 monosegmental posterior instrumented surgery. Of these, 36 patients were treated with rigid fusion (transforaminal lumbar interbody fusion) and 41 with dynamic stabilization [segmental spinal correction system (SSCS)]. Lumbar kinematics was evaluated with functional radiographs preoperatively and at final follow-up postoperatively. We defined the contribution of each segmental mobility to the total lumbar mobility as the percent segmental mobility [(sagittal angular motion of each segment in degrees)/(total sagittal angular motion in degrees) × 100]. Magnetic resonance imaging was performed on all patients preoperatively and at final follow-up postoperatively. The discs were classified into five grades based on the previously reported system. We defined the progress of disc degeneration as (grade at final follow-up) - (grade at preoperatively). No significant kinematical differences were shown at any of the lumbar segments preoperatively; however, significant differences were observed at the L2-3, L4-5, and L5-S1 segments postoperatively between the groups. At final follow-up, all of the lumbar segments with rigid fusion demonstrated significantly greater disc degeneration than those with dynamic stabilization. Our results suggest that the SSCS preserved 14% of the kinematical operations at the instrumented segment. The SSCS may prevent excessive effects on adjacent segmental kinematics and may prevent the incidence of adjacent segment disorder. PMID:21301893

Morishita, Yuichiro; Ohta, Hideki; Naito, Masatoshi; Matsumoto, Yoshiyuki; Huang, George; Tatsumi, Masato; Takemitsu, Yoshiharu; Kida, Hirotaka

2011-09-01

192

Cold fusion: Alchemist's dream  

NASA Astrophysics Data System (ADS)

In this report the following topics relating to cold fusion are discussed: muon catalyzed cold fusion; piezonuclear fusion; sundry explanations pertaining to cold fusion; cosmic ray muon catalyzed cold fusion; vibrational mechanisms in excited states of D2 molecules; barrier penetration probabilities within the hydrogenated metal lattice/piezonuclear fusion; branching ratios of D2 fusion at low energies; fusion of deuterons into He-4; secondary D+T fusion within the hydrogenated metal lattice; helium-3 to helium-4 ratio within the metal lattice; shock induced fusion; and anomalously high isotopic ratios of helium-3/helium-4.

Clayton, E. D.

1989-09-01

193

The development of whole blood titanium levels after instrumented spinal fusion - Is there a correlation between the number of fused segments and titanium levels?  

PubMed Central

Background Most modern spinal implants contain titanium and remain in the patient’s body permanently. Local and systemic effects such as tissue necrosis, osteolysis and malignant cell transformation caused by implants have been described. Increasing tissue concentration and whole blood levels of ions are necessary before a disease caused by a contaminant develops. The aim of the present study was the measurement of whole blood titanium levels and the evaluation of a possible correlation between these changes and the number of fused segments. Methods A prospective study was designed to determine changes in whole blood titanium levels after spinal fusion and to analyze the correlation to the number of pedicle screws, cross connectors and interbody devices implanted. Blood samples were taken preoperatively in group I (n?=?15), on the first, second and 10th day postoperatively, as well as 3 and 12?months after surgery. Group II (n?=?16) served as a control group of volunteers who did not have any metal implants in the body. Blood samples were taken once in this group. The number of screw-rod-connections and the length of the spinal fusion were determined using radiographic pictures. This study was checked and approved by the ethical committee of the University of Tuebingen. Results The mean age in group I was 47?±?22?years (range 16 - 85?years). There were three male (20%) and twelve female (80%) patients. The median number of fused segments was 5 (range 1 to 11 segments). No statistically significant increase in the titanium level was seen 12?months after surgery (mean difference: -7.2??g/l, 95% CI: -26.9 to 12.5??g/l, p?=?0.446). By observing the individual titanium levels, 4 out of 15 patients demonstrated an increase in titanium levels 12?months after surgery. No statistically significant correlation between fused segments (r?=?-0.188, p?=?0.503) length of instrumentation (r?=?-0.329, p?=?0.231), number of interbody devices (r?=?-0.202, p?=?0.291) and increase of titanium levels over the observation period was seen. Conclusions Instrumented spinal fusion does not lead to a statistically significant increase in whole blood titanium levels. There seems to be no correlation between the number of pedicle screws, cross connectors and interbody devices implanted and the increase of serum titanium levels.

2012-01-01

194

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 3: Assessment of economic outcome.  

PubMed

A comprehensive economic analysis generally involves the calculation of indirect and direct health costs from a societal perspective as opposed to simply reporting costs from a hospital or payer perspective. Hospital charges for a surgical procedure must be converted to cost data when performing a cost-effectiveness analysis. Once cost data has been calculated, quality-adjusted life year data from a surgical treatment are calculated by using a preference-based health-related quality-of-life instrument such as the EQ-5D. A recent cost-utility analysis from a single study has demonstrated the long-term (over an 8-year time period) benefits of circumferential fusions over stand-alone posterolateral fusions. In addition, economic analysis from a single study has found that lumbar fusion for selected patients with low-back pain can be recommended from an economic perspective. Recent economic analysis, from a single study, finds that femoral ring allograft might be more cost-effective compared with a specific titanium cage when performing an anterior lumbar interbody fusion plus posterolateral fusion. PMID:24980580

Ghogawala, Zoher; Whitmore, Robert G; Watters, William C; Sharan, Alok; Mummaneni, Praveen V; Dailey, Andrew T; Choudhri, Tanvir F; Eck, Jason C; Groff, Michael W; Wang, Jeffrey C; Resnick, Daniel K; Dhall, Sanjay S; Kaiser, Michael G

2014-07-01

195

Nell-1 Protein Promotes Bone Formation in a Sheep Spinal Fusion Model  

PubMed Central

Bone morphogenetic proteins (BMPs) are widely used as bone graft substitutes in spinal fusion, but are associated with numerous adverse effects. The growth factor Nel-like molecule-1 (Nell-1) is mechanistically distinct from BMPs and can minimize complications associated with BMP therapies. This study evaluates the efficacy of Nell-1 combined with demineralized bone matrix (DBM) as a novel bone graft material for interbody spine fusion using sheep, a phylogenetically advanced animal with biomechanical similarities to human spine. Nell-1+sheep DBM or Nell-1+heat-inactivated DBM (inDBM) (to determine the osteogenic effect of residual growth factors in DBM) were implanted in surgical sites as follows: (1) DBM only (control) (n=8); (2) DBM+0.3?mg/mL Nell-1 (n=8); (3) DBM+0.6?mg/mL Nell-1 (n=8); (4) inDBM only (control) (n=4); (5) inDBM+0.3?mg/mL Nell-1 (n=4); (6) inDBM+0.6?mg/mL Nell-1 (n=4). Fusion was assessed by computed tomography, microcomputed tomography, and histology. One hundred percent fusion was achieved by 3 months in the DBM+0.6?mg/mL Nell-1 group and by 4 months in the inDBM+0.6?mg/mL Nell-1 group; bone volume and mineral density were increased by 58% and 47%, respectively. These fusion rates are comparable to published reports on BMP-2 or autograft bone efficacy in sheep. Nell-1 is an independently potent osteogenic molecule that is efficacious and easily applied when combined with DBM.

Siu, Ronald K.; Lu, Steven S.; Li, Weiming; Whang, Julie; McNeill, Gabriel; Zhang, Xinli; Wu, Benjamin M.; Turner, A. Simon; Seim, Howard B.; Hoang, Paul; Wang, Jeffrey C.; Gertzman, Arthur A.; Ting, Kang

2011-01-01

196

Comparison between Instrumented Mini-TLIF and Instrumented Circumferential Fusion in Adult Low-Grade Lytic Spondylolisthesis : Can Mini-TLIF with PPF Replace Circumferential Fusion?  

PubMed Central

Objective To evaluate clinical and radiological results of two different fusion techniques in adult low-grade isthmic spondylolisthesis. Methods Between November 2003 and December 2004, 46 consecutive patients underwent instrumented mini-transforaminal lumbar interbody fusion (mini-TLIF) (group I) at Wooridul Spine Hospital, Seoul, Korea. Between February 2003 and October 2006, 32 consecutive patients underwent instrumented circumferential fusion (group II) at Leon Wiltse Memorial Hospital, Suwon, Korea. The mean follow-up periods were 29.7 and 26.1 months, respectively. Results Mean visual analog scale (VAS) scores for back and leg pain decreased, respectively, from 6.98 and 6.33 to 2.3 and 2.2 in group I and from 7.38 and 6.00 to 1.7 and 1.0 in group II. Mean Oswestry disability index (ODI) improved from 51.85% to 14.4% in group I and from 60% to 9.1% in group II. In both groups, VAS and ODI scores significantly changed from pre- to postoperatively (p<0.001), but postoperative outcome between groups was statistically not significant. Radiologic evidence of fusion was noted in 95.7% and 100% of the patients in group I and II, respectively. In both groups, changes in disc height, segmental lordosis, degree of listhesis, and whole lumbar lordosis between the pre- and postoperative periods were significant except whole lumbar lordosis in both groups. Conclusion Clinical and functional outcomes demonstrate no significant differences between groups in treating back and leg pain of adult patients with low-grade isthmic spondylolisthesis. However, in terms of operative data (i.e. operation time and hospital stay), instrumented mini-TLIF demonstrated better results.

Kim, Dong-Hyun; Lee, Sang-Ho

2009-01-01

197

Multi Sensor Data Fusion (Multisensor Data Fusion).  

National Technical Information Service (NTIS)

The present state of development of multisensor data fusion is presented as the MUltiSensor Image Processing (MUSIP) project, which developed a proof of concept software demonstrator for the fusion and analysis of remotely sensed images within a knowledge...

T. K. Pike C. Boesswetter

1991-01-01

198

Magnetized target fusion and fusion propulsion  

Microsoft Academic Search

Magnetized target fusion (MTF) is a thermonuclear fusion concept that is intermediate between the two mainline approaches, magnetic confinement and inertial confinement fusion (MCF and ICF). MTF incorporates some aspects of each and offers advantages over each of the mainline approaches. First, it provides a means of reducing the driver power requirements, thereby admitting a wider range of drivers than

Kirkpatrick

2001-01-01

199

Magnetized target fusion and fusion propulsion  

Microsoft Academic Search

Magnetized target fusion (MTF) is a thermonuclear fusion concept that is intermediate between the two mainline approaches, magnetic confinement and inertial confinement fusion (MCF and ICF). MTF incorporates some aspects of each and offers advantages over each of the mainline approaches. First, it provides a means of reducing the driver power requirements, thereby admitting a wider range of drivers than

Ronald C. Kirkpatrick

2002-01-01

200

Complications of anterior cervical discectomy and fusion using recombinant human bone morphogenetic protein-2  

PubMed Central

The use of bone morphogenetic protein-2 (rhBMP-2) in spinal fusion has increased dramatically since an FDA approval for its use in anterior lumbar fusion with the LT cage. There are several reports of its use in transforaminal lumbar interbody fusion, posterolateral fusion, and anterior cervical fusion. Reports on adverse effects of rhBMP-2 when used in spinal fusion are scarce in literature. An Institutional Review Board approved retrospective study was conducted in patients undergoing anterior spinal fusion and instrumentation following diskectomy at a single center. Forty-six consecutive patients were included. Twenty-two patients treated with rhBMP-2 and PEEK cages were compared to 24 in whom allograft spacers and demineralized bone matrix was used. Patients filled out Cervical Oswestry Scores, VAS for arm pain, neck pain, and had radiographs preoperatively as well at every follow up visit. Radiographic examination following surgery revealed end plate resorption in all patients in whom rhBMP-2 was used. This was followed by a period of new bone formation commencing at 6 weeks. In contrast, allograft patients showed a progressive blurring of end plate-allograft junction. Dysphagia was a common complication and it was significantly more frequent and more severe in patients in whom rhBMP-2 was used. Post operative swelling anterior to the vertebral body on lateral cervical spine X-ray was significantly larger in the rhBMP-2 group when measured from 1 to 6 weeks after which it was similar. These effects are possibly due to an early inflammatory response to rhBMP-2 and were observed to be dose related. With the parameters we used, there was no significant difference in the clinical outcome of patients in the two groups at 2 years. The cost of implants in patients treated with rhBMP-2 and PEEK spacers was more than three times the cost of allograft spacers and demineralized bone matrix in 1, 2, and 3-level cases. Despite providing consistently good fusion rates, we have abandoned using rhBMP-2 and PEEK cages for anterior cervical fusion, due to the side effects, high cost, and the availability of a suitable alternative.

Carp, Julia; Sethi, Anil; Bartol, Stephen; Craig, Joseph; Les, Clifford M.

2007-01-01

201

Sequential fusion  

NASA Astrophysics Data System (ADS)

A classification system such as an Automatic Target Recognition (ATR) system might yield better performance when fused sequentially than in parallel. Most fused systems have parallel architecture, but, the medical community often uses sequential tests due to costs constraints. We define the different types of sequential fusion and investigate their characteristics. We compare parallel fused systems with sequential fused systems. Another goal of this paper is to compare competing sequential fused systems to arrive at an optimal architecture design given the systems at hand. These systems may be legacy systems whose performances are well known. If these systems have known Receiver Operating Characteristic (ROC) curves/manifolds then we derive a formula that yields the ROC curve/manifold for the resultant sequentially fused system, thus, enabling one to make these comparisons. This formula is distribution free. We give an example to demonstrate the utility of our method, and show that one can play "what if" scenarios.

Oxley, Mark E.; Daly, Kathleen E.; Schubert-Kabban, Christine M.; Zitelli, David A.

2011-05-01

202

Inertial Fusion Energy  

NSDL National Science Digital Library

This webpage from the National Ignition Facility (NIF) discusses the NIF Inertial Fusion Energy program, an effort to use lasers to begin fusion. The page includes more details on the process of fusion, complete with helpful pictures, and a few possible applications of fusion technology.

2010-03-31

203

Feature Level Sensor Fusion.  

National Technical Information Service (NTIS)

This paper describes two practical fusion techniques (hybrid fusion and cued fusion) for automatic target cueing that combine features derived from each sensor data at the object-level. In the hybrid fusion method each of the input sensor data is prescree...

T. Peli M. Young R. Knox K. Ellis F. Bennett

1999-01-01

204

Fusion Science Education Outreach  

Microsoft Academic Search

This presentation will focus on education outreach activities at General Atomics that have been expanded to include the general population on science education with a focus on fusion energy. Outreach materials are distributed upon request both nationally and internationally. These materials include a notebook containing copies of DIII--D tour panels, fusion poster, new fusion energy video, new fusion energy brochure,

C. A. Danielson

1996-01-01

205

Fusion energy  

SciTech Connect

The main purpose of the International Thermonuclear Experimental Reactor (ITER) is to develop an experimental fusion reactor through the united efforts of many technologically advanced countries. The ITER terms of reference, issued jointly by the European Community, Japan, the USSR, and the United States, call for an integrated international design activity and constitute the basis of current activities. Joint work on ITER is carried out under the auspices of the International Atomic Energy Agency (IAEA), according to the terms of quadripartite agreement reached between the European Community, Japan, the USSR, and the United States. The site for joint technical work sessions is at the MaxPlanck Institute of Plasma Physics. Garching, Federal Republic of Germany. The ITER activities have two phases: a definition phase performed in 1988 and the present design phase (1989--1990). During the definition phase, a set of ITER technical characteristics and supporting research and development (R D) activities were developed and reported. The present conceptual design phase of ITER lasts until the end of 1990. The objectives of this phase are to develop the design of ITER, perform a safety and environmental analysis, develop site requirements, define future R D needs, and estimate cost, manpower, and schedule for construction and operation. A final report will be submitted at the end of 1990. This paper summarizes progress in the ITER program during the 1989 design phase.

Not Available

1990-09-01

206

Multilevel image fusion  

NASA Astrophysics Data System (ADS)

Signal-level image fusion has in recent years established itself as a useful tool for dealing with vast amounts of image data obtained by disparate sensors. In many modern multisensor systems, fusion algorithms significantly reduce the amount of raw data that needs to be presented or processed without loss of information content as well as provide an effective way of information integrations. One of the most useful and widespread applications of signal-level image fusion is for display purposes. Fused images provide the observer with a more reliable and more complete representation of the scene than would be obtained through single sensor display configurations. In recent years, a plethora of algorithms that deal with problem of fusion for display has been proposed. However, almost all are based on relatively basic processing techniques and do not consider information from higher levels of abstraction. As some recent studies have shown this does not always satisfy the complex demands of a human observer and a more subjectively meaningful approach is required. This paper presents a fusion framework based on the idea that subjectively relevant fusion could be achieved in information at higher levels of abstraction such as image edges and image segment boundaries are used to guide the basic signal-level fusion process. Fusion of processed, higher level information to form a blueprint for fusion at signal level and fusion of information from multiple levels of extraction into a single fusion engine are both considered. When tested on two conventional signal-level fusion methodologies, such multi-level fusion structures eliminated undesirable effects such as a fusion artifacts and loss of visually vital information that compromise their usefulness. Images produced by inclusion of multi-level information in the fusion process are clearer and of generally better quality than those obtained through conventional low-level fusion. This is verified through subjective evaluation and established objective fusion performance metrics.

Petrovic, Vladimir

2003-04-01

207

Complications due to the use of BMP/INFUSE in spine surgery: The evidence continues to mount  

PubMed Central

Increasingly, adverse events (AE) attributed to utilizing BMP/INFUSE (Bone Morphogenetic Protein, Medtronic, Memphis, TN, USA) “off-label” in spine surgery are being reported. In 2008, the Food and Drug Administration (FDA) issued a warning that in anterior cervical spine surgery, the “off-label” use of BMP/INFUSE contributed to marked dysphagia, hematoma, seroma, swelling, and/or the need for intubation/tracheostomy. Subsequent studies have cited the following AE; heterotopic ossification (HO), osteolysis, infection, arachnoiditis, increased neurological deficits, retrograde ejaculation, and cancer. Furthermore, in 2011, Carragee et al. noted that 13 of the original industry-sponsored BMP/INFUSE spinal surgery studies failed to acknowledge multiple AE. Additionally, in 2012, Comer et al. observed that the frequency of retrograde ejaculation reported for BMP/INFUSE used “on-label” to perform Anterior Lumbar Interbody Fusion/Lumbar Tapered Fusion-Cage Device (ALIF/LT-Cage) was also largely “under-reported.” To summarize, there is mounting evidence in the spinal literature that utilizing BMP/INFUSE in spinal fusions contributes to major perioperative and postoperative morbidity.

Epstein, Nancy E.

2013-01-01

208

Alternative Approaches to Fusion.  

National Technical Information Service (NTIS)

The limitations of the Tokamak fusion reactor concept are discussed and various other fusion reactor concepts are considered that employ the containment of thermonuclear plasmas by magnetic fields (i.e., stellarators). Progress made in the containment of ...

R. J. Roth

1976-01-01

209

Review of 'cold fusion'.  

National Technical Information Service (NTIS)

This review describes the results from the following works: (1) to overview the chronological history of 'cold fusion' including the International Conferences on cold fusion (ICCF-3 and ICCF-4), (2) to overview the various theories which can explain the '...

1995-01-01

210

ChemTeacher: Fusion  

NSDL National Science Digital Library

ChemTeacher compiles background information, videos, articles, demonstrations, worksheets and activities for high school teachers to use in their classrooms. The Fusion page includes resources for teaching students about the discovery and applications of fusion.

2011-01-01

211

Horseshoe Kidney (Renal Fusion)  

MedlinePLUS

... sit amet, consectetur adipiscing elit. Horseshoe Kidney (Renal Fusion) Most people are born with two kidneys, which ... as is the case for people with renal fusion abnormalities. The following information will help you talk ...

212

Fusion Metrics Final Report.  

National Technical Information Service (NTIS)

In the Fusion Metrics program, a multi-sensor testbed was developed and an associated multisensor fusion system was demonstrated in an initial data collection. In developing this testbed, algorithms developed in part in previous Air Force research program...

D. Fay P. Ilardi S. Haron

2009-01-01

213

Fusion ignition research experiment.  

National Technical Information Service (NTIS)

Understanding the properties of high gain (alpha-dominated) fusion plasmas in an advanced toroidal configuration is the largest remaining open issue that must be addressed to provide the scientific foundation for an attractive magnetic fusion reactor. The...

D. Meade

2000-01-01

214

Energy from inertial fusion  

Microsoft Academic Search

Progress in drivers, reactors and targets has made smaller, more flexible power plants feasible and has reduced the potential costs of developing them. Fusion is potentially a safe, clean energy source not limited by political boundaries. Magnetic and inertial fusion share this promise, but there are differences between them. An inertial fusion power plant is based on different physics and

William J. Hogan; Roger Bangerter; Gerald L. Kulcinski

1992-01-01

215

Slow liner fusion  

SciTech Connect

{open_quotes}Slow{close_quotes} liner fusion ({approximately}10 ms compression time) implosions are nondestructive and make repetitive ({approximately} 1 Hz) pulsed liner fusion reactors possible. This paper summarizes a General Atomics physics-based fusion reactor study that showed slow liner feasibility, even with conservative open-line axial magnetic field confinement and Bohm radial transport.

Shaffer, M.J.

1997-08-01

216

Magnetized target fusion and fusion propulsion  

NASA Astrophysics Data System (ADS)

Magnetized target fusion (MTF) is a thermonuclear fusion concept that is intermediate between the two mainline approaches, magnetic confinement and inertial confinement fusion (MCF and ICF). MTF incorporates some aspects of each and offers advantages over each of the mainline approaches. First, it provides a means of reducing the driver power requirements, thereby admitting a wider range of drivers than ICF. Second, the magnetic field is only used for insulation, not confinement, and the plasma is wall confined, so that plasma instabilities are traded in for hydrodynamic instabilities. However, the degree of compression required to reach fusion condition is lower than for ICF, so that hydrodynamic instabilities are much less threatening. The standoff driver innovation proposes to dynamically form the target plasma and a gaseous shell that compresses and confines the target plasma. Therefore, fusion target fabrication is traded in for a multiplicity of plasma guns, which must work in synchrony. The standoff driver embodiment of MTF leads to a fusion propulsion system concept that is potentially compact and lightweight. We will discuss the underlying physics of MTF and some of the details of the fusion propulsion concept using the standoff driver approach. We discuss here the optimization of an MTF target design for space propulsion. .

Kirkpatrick, Ronald C.

2002-01-01

217

Magnetized target fusion and fusion propulsion.  

SciTech Connect

Magnetized target fusion (MTF) is a thermonuclear fusion concept that is intermediate between the two mainline approaches, magnetic confinement and inertial confinement fusion (MCF and ICF). MTF incorporates some aspects of each and offers advantages over each of the mainline approaches. First, it provides a means of reducing the driver power requirements, thereby admitting a wider range of drivers than ICF. Second, the magnetic field is only used for insulation, not confinement, and the plasma is wall confined, so that plasma instabilities are traded in for hydrodynamic instabilities. However, the degree of compression required to reach fusion conditions is lower than for ICF, so that hydrodynamic instabilities are much less threatening. The standoff driver innovation proposes to dynamically form the target plasma and a gaseous shell that compresses and confines the target plasma. Therefore, fusion target fabrication is traded in for a multiplicity of plasma guns, which must work in synchrony. The standoff driver embodiment of MTF leads to a fusion propulsion system concept that is potentially compact and lightweight. We will discuss the underlying physics of MTF and some of the details of the fusion propulsion concept using the standoff driver approach. We discuss here the optimization of an MTF target design for space propulsion.

Kirkpatrick, R. C. (Ronald C.)

2001-01-01

218

Biomechanical comparison of three stand-alone lumbar cages -- a three-dimensional finite element analysis  

PubMed Central

Background For anterior lumbar interbody fusion (ALIF), stand-alone cages can be supplemented with vertebral plate, locking screws, or threaded cylinder to avoid the use of posterior fixation. Intuitively, the plate, screw, and cylinder aim to be embedded into the vertebral bodies to effectively immobilize the cage itself. The kinematic and mechanical effects of these integrated components on the lumbar construct have not been extensively studied. A nonlinearly lumbar finite-element model was developed and validated to investigate the biomechanical differences between three stand-alone (Latero, SynFix, and Stabilis) and SynCage-Open plus transpedicular fixation. All four cages were instrumented at the L3-4 level. Methods The lumbar models were subjected to the follower load along the lumbar column and the moment at the lumbar top to produce flexion (FL), extension (EX), left/right lateral bending (LLB, RLB), and left/right axial rotation (LAR, RAR). A 10 Nm moment was applied to obtain the six physiological motions in all models. The comparison indices included disc range of motion (ROM), facet contact force, and stresses of the annulus and implants. Results At the surgical level, the SynCage-open model supplemented with transpedicular fixation decreased ROM (>76%) greatly; while the SynFix model decreased ROM 56-72%, the Latero model decreased ROM 36-91%, in all motions as compared with the INT model. However, the Stabilis model decreased ROM slightly in extension (11%), lateral bending (21%), and axial rotation (34%). At the adjacent levels, there were no obvious differences in ROM and annulus stress among all instrumented models. Conclusions ALIF instrumentation with the Latero or SynFix cage provides an acceptable stability for clinical use without the requirement of additional posterior fixation. However, the Stabilis cage is not favored in extension and lateral bending because of insufficient stabilization.

2013-01-01

219

Fusion Energy Education  

NSDL National Science Digital Library

The basics of fusion are deceptively simple: the process powers the sun and other stars, and it all takes place when atomic nuclei collide at high speed. But many questions remain. How can humans develop and exploit fusion energy? Is there a way to convert it more efficiently into useful mechanical, electrical, or thermal energy? This intriguing site, created by the Lawrence Livermore National Laboratory and the Princeton Plasma Physics Laboratory, presents an online fusion course designed to teach students and others about how fusion works and how it might be harnessed in the future. Visitors can try out The Guided Tour to get started, or they can click on one of the Main Topics. These include Energy Sources and Conversions, Two Key Fusion Reactions, and Creating the Conditions for Fusion. Each section contains graphics, explanatory text, and various diagrams. The site also includes charts which can be printed out for classroom use.

220

Status of fusion maintenance  

SciTech Connect

Effective maintenance will be an essential ingredient in determining fusion system productivity. This level of productivity will result only after close attention is paid to the entire system as an entity and appropriate integration of the elements is made. The status of fusion maintenance is reviewed in the context of the entire system. While there are many challenging developmental tasks ahead in fusion maintenance, the required technologies are available in several high-technology industries, including nuclear fission.

Fuller, G.M.

1984-01-01

221

Viral membrane fusion  

Microsoft Academic Search

Infection by viruses having lipid-bilayer envelopes proceeds through fusion of the viral membrane with a membrane of the target cell. Viral 'fusion proteins' facilitate this process. They vary greatly in structure, but all seem to have a common mechanism of action, in which a ligand-triggered, large-scale conformational change in the fusion protein is coupled to apposition and merger of the

Stephen C Harrison

2008-01-01

222

Intense fusion neutron sources  

Microsoft Academic Search

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons\\/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion

B. V. Kuteev; P. R. Goncharov; V. Yu. Sergeev; V. I. Khripunov

2010-01-01

223

Multisensor Data Fusion  

Microsoft Academic Search

Multisensor data fusion is a key enabling technology in which information from a number of sources is integrated to form a\\u000a unified picture [1]. This concept has been applied to numerous fields and new applications are being explored constantly. Even though most multisensor\\u000a data fusion applications have been developed relatively recently, the notion of data fusion has always been around.

Pramod K. Varshney

2000-01-01

224

Cell fusions in mammals  

Microsoft Academic Search

Cell fusions are important to fertilization, placentation, development of skeletal muscle and bone, calcium homeostasis and\\u000a the immune defense system. Additionally, cell fusions participate in tissue repair and may be important to cancer development\\u000a and progression. A large number of factors appear to regulate cell fusions, including receptors and ligands, membrane domain\\u000a organizing proteins, proteases, signaling molecules and fusogenic proteins

Lars-Inge Larsson; Bolette Bjerregaard; Jan Fredrik Talts

2008-01-01

225

Intense fusion neutron sources  

Microsoft Academic Search

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects\\u000a of creating fission and fusion neutron sources with intensities of 1015–1021 neutrons\\/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes\\u000a and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of\\u000a fusion

B. V. Kuteev; P. R. Goncharov; V. Yu. Sergeev; V. I. Khripunov

2010-01-01

226

The European Fusion Programme  

SciTech Connect

The long-term objective of the European fusion programme is the harnessing of the power of fusion to help meet mankind's future energy needs.This paper describes the current research programme, the unique organisational character of the fusion programme, and European and world-wide co-operation. The future evolution of the programme as part of the European Research Area and the developments currently taking place in preparation for the possible construction of ITER, the next major step towards the realisation of fusion power, are discussed.

Antidormi, R.; Bartlett, D.; Bruhns, H. [European Commission (Belgium)

2004-03-15

227

Vacuole membrane fusion  

PubMed Central

Pore models of membrane fusion postulate that cylinders of integral membrane proteins can initiate a fusion pore after conformational rearrangement of pore subunits. In the fusion of yeast vacuoles, V-ATPase V0 sectors, which contain a central cylinder of membrane integral proteolipid subunits, associate to form a transcomplex that might resemble an intermediate postulated in some pore models. We tested the role of V0 sectors in vacuole fusion. V0 functions in fusion and proton translocation could be experimentally separated via the differential effects of mutations and inhibitory antibodies. Inactivation of the V0 subunit Vph1p blocked fusion in the terminal reaction stage that is independent of a proton gradient. ?vph1 mutants were capable of docking and trans-SNARE pairing and of subsequent release of lumenal Ca2+, but they did not fuse. The Ca2+-releasing channel appears to be tightly coupled to V0 because inactivation of Vph1p by antibodies blocked Ca2+ release. Vph1 deletion on only one fusion partner sufficed to severely reduce fusion activity. The functional requirement for Vph1p correlates to V0 transcomplex formation in that both occur after docking and Ca2+ release. These observations establish V0 as a crucial factor in vacuole fusion acting downstream of trans-SNARE pairing.

Bayer, Martin J.; Reese, Christoph; Buhler, Susanne; Peters, Christopher; Mayer, Andreas

2003-01-01

228

Vaginal Anomalies: Fusion and Duplication  

MedlinePLUS

... dolor sit amet, consectetur adipiscing elit. Vaginal Abnormalities: Fusion and Duplication Having two of everything may be ... if your child's doctor diagnoses an "anomaly of fusion and duplication." What causes vaginal fusion and duplication? ...

229

A polycaprolactone-tricalcium phosphate composite scaffold as an autograft-free spinal fusion cage in a sheep model.  

PubMed

Titanium (Ti) based spinal fusion cages are frequently used in the clinics for the treatment of spinal degeneration and related diseases, however, their further clinical application is generally harassed by several drawbacks such as stress shielding, non-biodegradability and additional bone grafting procedure. Our earlier work has demonstrated the efficacy of a biodegradable macro-porous polycaprolactone-tricalcium phosphate (PCL-TCP) composite scaffold in promoting bony tissue ingrowth as well as its ability to sustain mechanical loads upon implantation into an orthotopic defect site. In this study, we investigated the use of PCL-TCP scaffold as an autograft-free spinal fusion cage in a preclinical sheep model over 12 months, and compared the fusion efficacy against Ti cages incorporated with autografts. Results showed that despite PCL-TCP scaffold as an autograft-free cage attaining a slower fusion rate at early stage (6 month), it achieved similar degree of spinal fusion efficacy as Ti cages aided with autograft at 12 month post-operation as evidenced by the radiographic and histological evaluation. PCL-TCP cages alone demonstrated better bone ingrowth with 2.6 fold higher bone/interspace ratio (B/I) and more homogeneous bone tissue distribution compared with that of the Ti cages (88.10  ±  3.63% vs. 33.74  ±  2.78%, p < 0.05) as seen from the histological and micro-CT analysis. Moreover, besides the bone tissue ingrowth, a quantitative approach was illustrated to accurately evaluate the osteointegration of fusion cage with surrounding bone tissue, and showed a 1.36 fold higher degree of osteointegration occurred in PCL-TCP cage group than Ti cage group (CS/PC: 79.31  ±  3.15% vs 58.44  ±  2.43%, p < 0.05). Furthermore, biomechanical analysis showed comparable mechanical strength of fused segments in both groups in terms of the range of motion and stiffness at 12 month (p > 0.05). The degradation profile of the PCL-TCP cages was noted to increase in tandem with new bone ingrowth into the pores, while maintaining good structural integrity necessary for supporting the spinal interbody segments. Therefore, with the better osteointegration, more bone tissue ingrowth as well as its favorable biodegradable and radiolucent properties, PCL-TCP cage has been demonstrated to be a promising candidate as an autograft-free fusion cage for clinical application. PMID:24743032

Li, Yi; Wu, Zhi-gang; Li, Xiao-kang; Guo, Zheng; Wu, Su-hua; Zhang, Yong-quan; Shi, Lei; Teoh, Swee-hin; Liu, Yu-chun; Zhang, Zhi-yong

2014-07-01

230

Fusion Science Education Outreach  

NASA Astrophysics Data System (ADS)

This presentation will focus on education outreach activities at General Atomics that have been expanded to include the general population on science education with a focus on fusion energy. Outreach materials are distributed upon request both nationally and internationally. These materials include a notebook containing copies of DIII--D tour panels, fusion poster, new fusion energy video, new fusion energy brochure, and the electromagnetic spectrum curriculum. The 1996 Fusion Forum (held in the House Caucus Room) included a student/ teacher lunch with Energy Secretary Hazel O'Leary and a private visit to the Forum exhibits. The continuing partnership with Kearny High School includes lectures, job shadowing, internship, equipment donations and an award-winning electric car-racing program. Development of distribution by CD of the existing interactive fusion energy kiosk and a virtual reality tour of the DIII--D facility are underway. The DIII--D fusion education WWW site includes e-mail addresses to ``Ask the Wizard,'' and/or receive GA's outreach materials. Steve Rodecker, a local science teacher, aided by DIII--D fusion staff, won his second Tapestry Award; he also was named the ``1995 National Science Teacher of the Year'' and will be present to share his experiences with the DIII--D educational outreach program.

Danielson, C. A.; DIII-D Education Group

1996-11-01

231

Fusion Power Deployment  

SciTech Connect

Fusion power plants could be part of a future portfolio of non-carbon dioxide producing energy supplies such as wind, solar, biomass, advanced fission power, and fossil energy with carbon dioxide sequestration. In this paper, we discuss key issues that could impact fusion energy deployment during the last half of this century. These include geographic issues such as resource availability, scale issues, energy storage requirements, and waste issues. The resource needs and waste production associated with fusion deployment in the U.S. should not pose serious problems. One important feature of fusion power is the fact that a fusion power plant should be locatable within most local or regional electrical distribution systems. For this reason, fusion power plants should not increase the burden of long distance power transmission to our distribution system. In contrast to fusion power, regional factors could play an important role in the deployment of renewable resources such as wind, solar and biomass or fossil energy with CO2 sequestration. We examine the role of these regional factors and their implications for fusion power deployment.

J.A. Schmidt; J.M. Ogden

2002-02-06

232

Mechanics of membrane fusion  

Microsoft Academic Search

Diverse membrane fusion reactions in biology involve close contact between two lipid bilayers, followed by the local distortion of the individual bilayers and reformation into a single, merged membrane. We consider the structures and energies of the fusion intermediates identified in experimental and theoretical work on protein-free lipid bilayers. On the basis of this analysis, we then discuss the conserved

Leonid V Chernomordik; Michael M Kozlov

2008-01-01

233

Muon catalysed fusion  

Microsoft Academic Search

A decade ago it was established that one muon in a deuterium-tritium mixture can catalyse more than 100 nuclear fusion reactions and that this phenomenon could be used for the production of nuclear fuel and energy. This review presents the state of the art of muon catalysed fusion studies and its place among alternative methods of nuclear breeding. The main

L. I. Ponomarev

1990-01-01

234

Muon-catalyzed fusion  

Microsoft Academic Search

Great progress achieved in muon-catalyzed fusion research in the past decade now makes it possible to review careful quantitative calculations and measurements. The major experimental surprises have doubled the fusion yields, but direct energy production would appear to be excluded without a significant breakthrough.(AIP)

W. H. Breunlich; P. Kammel; J. S. Cohen; M. Leon

1989-01-01

235

Fusion and the cosmos  

Microsoft Academic Search

In the following investigation we pay special attention to the role of self- organization in fusion plasma physics and in the cosmos. We present a new approach to the expansion of the universe. Formally the technique developed relies on our experience from treating hot fusion plasmas. We account for the possibility that the universe, as it seems, could have a

H. Wilhelmsson

2004-01-01

236

Aspects of Phonological Fusion  

ERIC Educational Resources Information Center

Phonological fusion occurs when the phonemes of two different speech stimuli are combined into a new percept that is longer and linguistically more complex than either of the two inputs. The present article is an investigation of the conditions necessary and sufficient for fusion to occur. (Editor/RK)

Cutting, James E.

1975-01-01

237

Fusion in the Sun!  

NSDL National Science Digital Library

This simulation illustrates the general conditions necessary to begin fusion in the sun and other stars. You can vary the amount of hydrogen and the temperature in order to start a reaction. Click the "Instructions" button in the top right hand corner for more information on fusion and what the simulation shows. Java is required to use this applet.

Scharein, Rob

2010-03-31

238

Controlled Nuclear Fusion.  

ERIC Educational Resources Information Center

This publication is one of a series of information booklets for the general public published by The United States Atomic Energy Commission. Among the topics discussed are: Importance of Fusion Energy; Conditions for Nuclear Fusion; Thermonuclear Reactions in Plasmas; Plasma Confinement by Magnetic Fields; Experiments With Plasmas; High-Temperature…

Glasstone, Samuel

239

Laplacian based image fusion  

Microsoft Academic Search

A fundamental goal in multispectral image fusion is to combine relevant information from multiple spectral ranges while displaying a constant amount of data as a single channel. Because we expect synergy between the views afforded by different parts of the spectrum, producing output imagery with increased information beyond any of the individual imagery sounds simple. While fusion algorithms achieve synergy

Jesse Scott; Michael A. Pusateri

2010-01-01

240

Fusion ignition experiment  

Microsoft Academic Search

A fusion ignition experiment (IGNITEX) is described, the original concept for which was proposed by Rosenbluth, Weldon and Woodson. In this concept, a single-turn-coil tokamak device produces a self-sustained fusion reaction of the type T (d, n) ?. The basic idea is to employ a very high magnetic field and a very high plasma current to heat the plasma ohmically

R. Carrera; E. Montalvo

1990-01-01

241

FRTP fusion ignition experiment  

Microsoft Academic Search

The Field-Reversed Theta Pinch (FRTP) represents a promising confinement approach to fusion power. This possibility has become more evident as a result of the favorable confinement scaling predicted by our studies of Loss-Cone Scattering Transport (LCST). Therefore, a step towards a FRTP prototype power reactor is proposed here that involves an ignition experiment designed to study confinement of a fusion

G. H. Miley; Q. T. Fang; J. G. Gilligan

1982-01-01

242

Fusion-Fission Hybrids Driven By Heavy Ion Inertial Fusion  

Microsoft Academic Search

There is a desire to resolve fuel cycle issues for increasing the role of nuclear energy. The recent Laser Inertial Fusion-Fission Energy (LIFE) initiative that builds upon NIF ignition, is likely to rekindle national interest in developing intense, high power ion beam accelerators for fusion energy production and for fusion-fission hybrid concepts that combine an ion beam driven fusion neutron

P. A. Seidl

243

Biomechanical evaluation of a new AxiaLIF technique for two-level lumbar fusion  

PubMed Central

Single level axial lumbar interbody fusion (AxiaLIF) using a transsacral rod through a paracoccygeal approach has been developed with promising early clinical results and biomechanical stability. Recently, the transsacral rod has been extended to perform a two-level fusion at both L4–L5 and L5–S1 levels (AxiaLIF II). No biomechanical studies have been conducted on multilevel fusion using the AxiaLIF technique. In this study, the biomechanics of L4–S1 motion segments instrumented with the AxiaLIF II transsacral rod was evaluated. Six human cadaveric lumbosacral spine segments from L4 to S1 were used (age ranges 46–74 years). Unconstrained and non-destructive pure moments in axial torsion, lateral bending, and flexion extension were applied to each specimen following intact, standalone AxiaLIF II, and AxiaLIF II with two posterior fixation options: facet screws and pedicle screws with rods. Range of motion was calculated from the raw data collected with an optical motion tracking system. The two-level transsacral rod was successfully inserted in all the specimens. At L4–L5 level in axial torsion (AT) and flexion extension (FE), none of the surgical treatments showed statistically significant difference between the procedures (all P > 0.05) although facet screws and pedicle screws had higher stability on average. In lateral bending (LB), the two posterior fixation techniques had significantly higher construct stability (P < 0.05) than the standalone rod. No significant difference was found between facet screws and pedicle screws (P = 0.821). At L5–S1 level in AT and LB, none of the surgical treatments were found to be statistically significant (all P > 0.05). In FE, standalone two-level transsacral rod had significantly higher range of motion (ROM) compared with the posterior fixation techniques (P < 0.05). In conclusion, the standalone rod reduced intact ROM significantly. Supplementary fixations including facet screws and pedicle screws are required to achieve higher construct stability for successful fusion. Further clinical studies are essential to evaluate the practical success of this technique.

Erkan, Serkan; Mehbod, Amir A.; Hsu, Brian; Pahl, Douglas W.; Transfeldt, Ensor E.

2009-01-01

244

Spherical torus fusion reactor  

DOEpatents

The object of this invention is to provide a compact torus fusion reactor with dramatic simplification of plasma confinement design. Another object of this invention is to provide a compact torus fusion reactor with low magnetic field and small aspect ratio stable plasma confinement. In accordance with the principles of this invention there is provided a compact toroidal-type plasma confinement fusion reactor in which only the indispensable components inboard of a tokamak type of plasma confinement region, mainly a current conducting medium which carries electrical current for producing a toroidal magnet confinement field about the toroidal plasma region, are retained.

Martin Peng, Y.K.M.

1985-10-03

245

Cost effectiveness of disc prosthesis versus lumbar fusion in patients with chronic low back pain: randomized controlled trial with 2-year follow-up.  

PubMed

This randomized controlled health economic study assesses the cost-effectiveness of the concept of total disc replacement (TDR) (Charité/Prodisc/Maverick) when compared with the concept of instrumented lumbar fusion (FUS) [posterior lumbar fusion (PLF) /posterior lumbar interbody fusion (PLIF)]. Social and healthcare perspectives after 2 years are reported. In all, 152 patients were randomized to either TDR (n = 80) or lumbar FUS (n = 72). Cost to society (total mean cost/patient, Swedish kronor = SEK, standard deviation) for TDR was SEK 599,560 (400,272), and for lumbar FUS SEK 685,919 (422,903) (ns). The difference was not significant: SEK 86,359 (-45,605 to 214,332). TDR was significantly less costly from a healthcare perspective, SEK 22,996 (1,202 to 43,055). Number of days on sick leave among those who returned to work was 185 (146) in the TDR group, and 252 (189) in the FUS group (ns). Using EQ-5D, the total gain in quality adjusted life years (QALYs) over 2 years was 0.41 units for TDR and 0.40 units for FUS (ns). Based on EQ-5D, the incremental cost-effectiveness ratio (ICER) of using TDR instead of FUS was difficult to analyze due to the "non-difference" in treatment outcome, which is why cost/QALY was not meaningful to define. Using cost-effectiveness probabilistic analysis, the net benefit (with CI) was found to be SEK 91,359 (-73,643 to 249,114) (ns). We used the currency of 2006 where 1 EURO = 9.26 SEK and 1 USD = 7.38 SEK. It was not possible to state whether TDR or FUS is more cost-effective after 2 years. Since disc replacement and lumbar fusion are based on different conceptual approaches, it is important to follow these results over time. PMID:21053028

Fritzell, Peter; Berg, Svante; Borgström, Fredrik; Tullberg, Tycho; Tropp, Hans

2011-07-01

246

Fusion for Space Propulsion  

NASA Technical Reports Server (NTRS)

There is little doubt that humans will attempt to explore and develop the solar system in this century. A large amount of energy will be required for accomplishing this. The need for fusion propulsion is discussed. For a propulsion system, there are three important thermodynamical attributes: (1) The absolute amount of energy available, (2) the propellant exhaust velocity, and (3) the jet power per unit mass of the propulsion system (specific power). For human exploration and development of the solar system, propellant exhaust velocity in excess of 100 km/s and specific power in excess of 10 kW/kg are required. Chemical combustion can produce exhaust velocity up to about 5 km/s. Nuclear fission processes typically result in producing energy in the form of heat that needs to be manipulated at temperatures limited by materials to about 2,800 K. Using the energy to heat a hydrogen propellant increases the exhaust velocity by only a factor of about two. Alternatively the energy can be converted into electricity which is then used to accelerate particles to high exhaust velocity. The necessary power conversion and conditioning equipment, however, increases the mass of the propulsion system for the same jet power by more than two orders of magnitude over chemical system, thus greatly limits the thrust-to-weight ratio attainable. The principal advantage of the fission process is that its development is relatively mature and is available right now. If fusion can be developed, fusion appears to have the best of all worlds in terms of propulsion - it can provide the absolute amount, the propellant exhaust velocity, and the high specific jet power. An intermediate step towards pure fusion propulsion is a bimodal system in which a fission reactor is used to provide some of the energy to drive a fusion propulsion unit. The technical issues related to fusion for space propulsion are discussed. The technical priorities for developing and applying fusion for propulsion are somewhat different from those for terrestrial electrical power generation. Thus fusion schemes that are initially attractive for electrical power generation might not necessarily be attractive also for propulsion and vice versa, though the underlying fusion science and engineering enjoy much overlap. Parallel efforts to develop these qualitatively differently fusion schemes for the two applications could benefit greatly from each other due to the synergy in the underlying physics and engineering. Pulsed approaches to fusion have not been explored to the same degree as steady-state or long-pulse approaches to fusion in the fusion power research program. The concerns early on were several. One was that the pulsed power components might not have the service lifetimes meeting the requirements of a practical power generating plant. Another was that, for many pulsed fusion schemes, it was not clear whether the destruction of hardware per pulse could be minimized or eliminated or recycled to such an extent as to make economical electrical power generation feasible, Significant development of the underlying pulsed power component technologies have occurred in the last two decades because of defense and other energy requirements. The state of development of the pulsed power technologies are sufficiently advanced now to make it compelling to visit or re-visit pulsed fusion approaches for application to propulsion where the cost of energy is not so demanding a factor as in the case of terrestrial power application. For propulsion application, the overall mass of the fusion system is the critical factor. Producing fusion reactions require extreme states of matter. Conceptually, these extreme states of matter are more readily realizable in the pulsed states, at least within appropriate bounds, than in the steady states. Significant saving in system mass may result in such systems. Magnetic fields are effective in confining plasma energy, whereas inertial compression is an effective way of heating and containing the plasma. Intensive research in developing magnetic energy containme

Thio, Y. C. Francis; Schafer, Charles (Technical Monitor)

2001-01-01

247

Nuclear fusion - Focus on Tokamak  

Microsoft Academic Search

An overview of nuclear fusion engineering is presented covering: basic fusion technology, magnetic and inertial confinement schemes, fusion fuel, tritium breeding, blankets, tritium containment and disposal, fusion process waste management, power generation costs, environmental impact, and safety. Attention is focused on closed magnetic confinement systems, specifically Tokamak systems. The outlook for pulsed\\/batch or continuous Tokamak operation is assessed. Power supplies

D. Steiner

1977-01-01

248

Information Fusion in Face Identification  

Microsoft Academic Search

Information Fusion of multi-modal Biometrics has attracted much attention in recent years. However, this paper focuses on the information fusion in single modals, that is, the face Biometric. Two different representation methods, gray level intensity and Gabor feature, are exploited for fusion. We study the fusion problem in face recognition at both the face representation level and the confidence level.

Wenchao Zhang; Shiguang Shan; Wen Gao; Yizheng Chang; Bo Cao; Peng Yang

2004-01-01

249

Information fusion in face identification  

Microsoft Academic Search

Information fusion of multi-modal biometrics has attracted much attention in recent years. However, this paper focuses on the information fusion in single models, that is, the face biometric. Two different representation methods, gray level intensity and Gabor feature, are exploited for fusion. We study the fusion problem in face recognition at both the face representation level and the confidence level.

Wenchao Zhang; Shiguang Shan; Wen Gao; Yizheng Chang; Bo Cao; Peng Yang

2004-01-01

250

Fusion Ignition Research Experiment  

NSDL National Science Digital Library

This site contains extensive status reports regarding background information and reviews of international fusion research and policy. Focus is on two projects, FIRE and ITER, with reports on physics and engineering design considerations, and an engineering appendix.

Laboratory, Princeton P.

2003-10-10

251

Fusion Research Activities, 1979.  

National Technical Information Service (NTIS)

The research activities in plasma physics and controlled fusion during 1978 are summarized as well as the plans for continued activites during 1979. The research program includes investigations into plasma-neutral gas interaction and stability, magnetic c...

B. Lehnert

1979-01-01

252

On cold fusion  

Microsoft Academic Search

This paper argues that a high negative voltage on a metal into which deuterium is soaked might enhance fusion reactions. The author discusses how this may have been the way Fleischmann and Pons achieved their results.

Spinrad

1990-01-01

253

Fusion driver study  

NASA Astrophysics Data System (ADS)

A conceptual design of multimegajoule, repetitively pulsed CO2 laser system for Inertial Confinement Fusion is presented. System configurations consisting of 50-100 kJ modules operating at subatmospheric pressures with multiple pass optical extraction appear feasible with present or near term technology. Overall laser system efficiencies of greater than 10% at repetition rates in excess of 10 Hz are possible with the state of the art pulsed power technology. The synthesis of all the laser subsystems into a specific configuration for a Laser Fusion Driver depends upon the reactor chamber(s) layout, subsystem reliability and restrictions on overall dimensions of the fusion driver. A design is presented which stacks power amplifier modules in series in a large torus with centrally located reactor chamber. Cost estimates of the overall laser fusion driver are included.

Friedman, H. W.

1980-04-01

254

Fusion Energy Sciences  

NSDL National Science Digital Library

As part of the US Department of Energy, the Office of Science contains the Fusion Energy Sciences program, whose mission is to advance plasma science and fusion science technology. The program "supports research to understand the physics of plasmas; to identify and explore innovative and cost-effective development paths to fusion energy; and as a partner in international efforts, to advance the science and technology of energy-producing plasmas." Visitors to the Fusion Energy Sciences Web site will find current news related to the program, a program highlights document, several informative published papers, additional links, and more. If you're interested in energy, physics, or other related sciences, you'll definitely enjoy learning about the cutting edge science being undertaken within the department.

1969-12-31

255

Fusion: The Hydrogen Bomb  

NSDL National Science Digital Library

Just after World War II, nuclear scientists turned their attention from fission to fusion. This video segment adapted from AMERICAN EXPERIENCE looks at the beginnings of thermonuclear power generation.

Foundation, Wgbh E.

2004-02-20

256

Inertial Confinement Fusion.  

National Technical Information Service (NTIS)

In these notes, we discuss inertially confined thermonuclear fusion obtained by means of spherically imploded deuterium-tritium fuel. The emphasis is on the 'inner part' of ICF physics, on the implosion dynamics, central fuel ignition, and energy gain, ra...

J. Meyer-ter-Vehn

1985-01-01

257

Indian fusion test reactor  

NASA Astrophysics Data System (ADS)

The fusion reactor as a volumetric neutron source can serve many applications needed for realizing fusion power reactor. For the Indian energy scenario, such a device can also produce fissile fuel for accelerating the nuclear power production. The Indian Fusion Test Reactor (FTR) is a low fusion gain (Q = 3-5) device to be used as component test facility for qualifying future reactor materials as well as for demonstrating the production of fissile fuel. FTR will be a medium sized tokamak device with a neutron wall load of 0.2 MW/m2. The presently available structural materials can be used for this device and such a device can be realized in ten years time from now. This device should produce about 25-50 kg of fissile fuel in one full-power-year and also produce the tritium needed for its operation. This device will greatly help the nuclear fission power program by producing fissile fuel.

Srinivasan, R.; FTR Team

2012-06-01

258

FRTP Fusion Ignition Experiment.  

National Technical Information Service (NTIS)

The Field-Reversed Theta Pinch (FRTP) represents a promising confinement approach to fusion power. This possibility has become more evident as a result of the favorable confinement scaling predicted by our studies of Loss-Cone Scattering Transport (LCST)....

G. H. Miley, Q. T. Fang, J. G. Gilligan

1982-01-01

259

Synergetic Multisensor Fusion.  

National Technical Information Service (NTIS)

Synergetic multisensor fusion is the process of integrating information obtained from different sensing modalities in order to extract additional information that cannot be obtained by separately processing the signals from the different sensors. The deve...

J. K. Aggarwal

1990-01-01

260

Advanced spheromak fusion reactor.  

National Technical Information Service (NTIS)

The spheromak has no toroidal magnetic field coils or other structure along its geometric axis, and is thus more attractive than the leading magnetic fusion reactor concept, the tokamak. As a consequence of this and other attributes, the spheromak reactor...

T. K. Fowler E. B. Hooper

1996-01-01

261

HIV fusion inhibitors.  

PubMed

Drugs based on amino acid sequence of Heptad Repeats of gp41 of HIV have been explored in search of anti-HIV drugs acting by inhibition of the gp41 6-helix formation and subsequent cellular infection. These are classified under a distinct discipline called HIV fusion inhibitors. Resistance to HIV fusion inhibitors and their solutions have also been discussed in this review. PMID:19827030

Qadir, M I; Malik, S A

2010-01-01

262

Synaptic vesicle fusion  

Microsoft Academic Search

The core of the neurotransmitter release machinery is formed by SNARE complexes, which bring the vesicle and plasma membranes together and are key for fusion, and by Munc18-1, which controls SNARE-complex formation and may also have a direct role in fusion. In addition, SNARE complex assembly is likely orchestrated by Munc13s and RIMs, active-zone proteins that function in vesicle priming

Josep Rizo; Christian Rosenmund

2008-01-01

263

Cold nuclear fusion  

NASA Astrophysics Data System (ADS)

Recent accelerator experiments on fusion of various elements have clearly demonstrated that the effective cross-sections of these reactions depend on what material the target particle is placed in. In these experiments, there was a significant increase in the probability of interaction when target nuclei are imbedded in a conducting crystal or are a part of it. These experiments open a new perspective on the problem of so-called cold nuclear fusion.

Tsyganov, E. N.

2012-02-01

264

Cold nuclear fusion  

Microsoft Academic Search

The possibility that negative muons could catalyze nuclear fusion was suggested on theoretical grounds by F.C. Frank and A.D. Sakharov in the late 1940s; the first experimental observations of the process followed serendipitously a decade later, in experiments at Berkeley by L.W. Alvarez. The fastest mechanism for muon-catalyzed, or 'cold' fusion, was suggested by Vesman (1967); it depends on a

Johann Rafelski; Steven E. Jones

1987-01-01

265

Fusion ignition research experiment  

SciTech Connect

Understanding the properties of high gain (alpha-dominated) fusion plasmas in an advanced toroidal configuration is the largest remaining open issue that must be addressed to provide the scientific foundation for an attractive magnetic fusion reactor. The critical parts of this science can be obtained in a compact high field tokamak which is also likely to provide the fastest and least expensive path to understanding alpha-dominated plasmas in advanced toroidal systems.

Dale Meade

2000-07-18

266

Fusion pumped laser  

Microsoft Academic Search

The apparatus of this invention may comprise a system for generating laser radiation from a high-energy neutron source. The neutron source is a tokamak fusion reactor generating a long pulse of high-energy neutrons and having a temperature and magnetic field effective to generate a neutron flux of at least 10¹⁵ neutrons\\/cm²\\/center dot\\/s. Conversion means are provided adjacent the fusion reactor

1987-01-01

267

ITER Fusion Energy  

ScienceCinema

ITER (in Latin ?the way?) is designed to demonstrate the scientific and technological feasibility of fusion energy. Fusion is the process by which two light atomic nuclei combine to form a heavier over one and thus release energy. In the fusion process two isotopes of hydrogen ? deuterium and tritium ? fuse together to form a helium atom and a neutron. Thus fusion could provide large scale energy production without greenhouse effects; essentially limitless fuel would be available all over the world. The principal goals of ITER are to generate 500 megawatts of fusion power for periods of 300 to 500 seconds with a fusion power multiplication factor, Q, of at least 10. Q ? 10 (input power 50 MW / output power 500 MW). The ITER Organization was officially established in Cadarache, France, on 24 October 2007. The seven members engaged in the project ? China, the European Union, India, Japan, Korea, Russia and the United States ? represent more than half the world?s population. The costs for ITER are shared by the seven members. The cost for the construction will be approximately 5.5 billion Euros, a similar amount is foreseen for the twenty-year phase of operation and the subsequent decommissioning.

Dr. Norbert Holtkamp

2010-01-08

268

Magnetized Target Fusion  

NASA Technical Reports Server (NTRS)

Magnetized target fusion (MTF) is under consideration as a means of building a low mass, high specific impulse, and high thrust propulsion system for interplanetary travel. This unique combination is the result of the generation of a high temperature plasma by the nuclear fusion process. This plasma can then be deflected by magnetic fields to provide thrust. Fusion is initiated by a small traction of the energy generated in the magnetic coils due to the plasma's compression of the magnetic field. The power gain from a fusion reaction is such that inefficiencies due to thermal neutrons and coil losses can be overcome. Since the fusion reaction products are directly used for propulsion and the power to initiate the reaction is directly obtained from the thrust generation, no massive power supply for energy conversion is required. The result should be a low engine mass, high specific impulse and high thrust system. The key is to successfully initiate fusion as a proof-of-principle for this application. Currently MSFC is implementing MTF proof-of-principle experiments. This involves many technical details and ancillary investigations. Of these, selected pertinent issues include the properties, orientation and timing of the plasma guns and the convergence and interface development of the "pusher" plasma. Computer simulations of the target plasma's behavior under compression and the convergence and mixing of the gun plasma are under investigation. This work is to focus on the gun characterization and development as it relates to plasma initiation and repeatability.

Griffin, Steven T.

2002-01-01

269

ITER Fusion Energy  

SciTech Connect

ITER (in Latin “the way”) is designed to demonstrate the scientific and technological feasibility of fusion energy. Fusion is the process by which two light atomic nuclei combine to form a heavier over one and thus release energy. In the fusion process two isotopes of hydrogen – deuterium and tritium – fuse together to form a helium atom and a neutron. Thus fusion could provide large scale energy production without greenhouse effects; essentially limitless fuel would be available all over the world. The principal goals of ITER are to generate 500 megawatts of fusion power for periods of 300 to 500 seconds with a fusion power multiplication factor, Q, of at least 10. Q ? 10 (input power 50 MW / output power 500 MW). The ITER Organization was officially established in Cadarache, France, on 24 October 2007. The seven members engaged in the project – China, the European Union, India, Japan, Korea, Russia and the United States – represent more than half the world’s population. The costs for ITER are shared by the seven members. The cost for the construction will be approximately 5.5 billion Euros, a similar amount is foreseen for the twenty-year phase of operation and the subsequent decommissioning.

Dr. Norbert Holtkamp

2009-12-01

270

Improvements of image fusion methods  

NASA Astrophysics Data System (ADS)

Fusion of images from different imaging modalities, obtained by conventional fusion methods, may cause artifacts, including destructive superposition and brightness irregularities, in certain cases. This paper proposes two methods for improving image multimodal fusion quality. Based on the finding that a better fusion can be achieved when the images have a more positive correlation, the first method is a decision algorithm that runs at the preprocessing fusion stage and determines whether a complementary gray level of one of the input images should be used instead of the original one. The second method is suitable for multiresolution fusion, and it suggests choosing only one image from the lowest-frequency sub-bands in the pyramids, instead of combining values from both sub-bands. Experimental results indicate that the proposed fusion enhancement can reduce fusion artifacts. Quantitative fusion quality measures that support this conclusion are shown.

Ben-Shoshan, Yotam; Yitzhaky, Yitzhak

2014-03-01

271

Craniocervical fusions in children.  

PubMed

The surgical management of craniovertebral junction (CVJ) instability in pediatric patients presents unique challenges. As compared with the adult patient, the anatomical variations of the CVJ in the pediatric patient are significant, complicate the approach, and limit the use of internal fixation. Diminutive osseous and ligamentous structures and syndromic craniovertebral abnormalities complicate the issue. Advances in imaging analysis and instrumentation have improved the armamentarium for managing the pediatric patient who requires craniocervical stabilization. In this paper, the author's experience of performing more than 850 pediatric CVJ fusions is reviewed. This work includes the indications for atlantoaxial arthrodesis and occipitocervical fusion. Early atlantoaxial fusions were performed using interlaminar rib graft fusion, and more recently using either transarticular screw fixation in the older patient, or lateral mass screws at C-1 and rod fixation with either C-2 pars interarticular screw fixation or pedicle screw fixation. A C-2 translaminar screw fixation is also described. Occipitocervical fusions are performed with rib grafts in patients younger than 6 years of age. Subsequently, above that age, contoured loop fixation was performed, and in the past 8-10 years, screw and rod fixation was used. Abnormal spine growth was not observed in children who underwent craniocervical stabilization below the age of 5 years (clearly the bone grew with the patient). However, no deleterious effects were noted in the children treated with rigid instrumentation. The success rate for bone fusion alone was 98%. The author's success rate with rigid instrumentation is nearly 100%. A detailed review of the technique of fusion is presented, as well as the indications and means of avoidance of complications, their prevention, and management. PMID:22656246

Menezes, Arnold H

2012-06-01

272

STATs and macrophage fusion  

PubMed Central

Macrophages play a pivotal role in host defense against multiple foreign materials such as bacteria, parasites and artificial devices. Some macrophage lineage cells, namely osteoclasts and foreign body giant cells (FBGCs), form multi-nuclear giant cells by the cell–cell fusion of mono-nuclear cells. Osteoclasts are bone-resorbing cells, and are formed in the presence of RANKL on the surface of bones, while FBGCs are formed in the presence of IL-4 or IL-13 on foreign materials such as artificial joints, catheters and parasites. Recently, fusiogenic mechanisms and the molecules required for the cell–cell fusion of these macrophage lineage cells were, at least in part, clarified. Dendritic cell specific transmembrane protein (DC-STAMP) and osteoclast stimulatory transmembrane protein (OC-STAMP), both of which comprise seven transmembrane domains, are required for both osteoclast and FBGC cell–cell fusion. STAT6 was demonstrated to be required for the cell–cell fusion of FBGCs but not osteoclasts. In this review, advances in macrophage cell–cell fusion are discussed.

2013-01-01

273

Simulation of Fusion Plasmas  

ScienceCinema

The upcoming ITER experiment (www.iter.org) represents the next major milestone in realizing the promise of using nuclear fusion as a commercial energy source, by moving into the ?burning plasma? regime where the dominant heat source is the internal fusion reactions. As part of its support for the ITER mission, the US fusion community is actively developing validated predictive models of the behavior of magnetically confined plasmas. In this talk, I will describe how the plasma community is using the latest high performance computing facilities to develop and refine our models of the nonlinear, multiscale plasma dynamics, and how recent advances in experimental diagnostics are allowing us to directly test and validate these models at an unprecedented level.

Chris Holland

2010-01-08

274

Spherical torus fusion reactor  

DOEpatents

A fusion reactor is provided having a near spherical-shaped plasma with a modest central opening through which straight segments of toroidal field coils extend that carry electrical current for generating a toroidal magnet plasma confinement fields. By retaining only the indispensable components inboard of the plasma torus, principally the cooled toroidal field conductors and in some cases a vacuum containment vessel wall, the fusion reactor features an exceptionally small aspect ratio (typically about 1.5), a naturally elongated plasma cross section without extensive field shaping, requires low strength magnetic containment fields, small size and high beta. These features combine to produce a spherical torus plasma in a unique physics regime which permits compact fusion at low field and modest cost.

Peng, Yueng-Kay M. (Oak Ridge, TN)

1989-01-01

275

Simulation of Fusion Plasmas  

ScienceCinema

The upcoming ITER experiment represents the next major milestone in realizing the promise of using nuclear fusion as a commercial energy source, by moving into the 'burning plasma' regime where the dominant heat source is the internal fusion reactions. As part of its support for the ITER mission, the US fusion community is actively developing validated predictive models of the behavior of magnetically confined plasmas. In this talk, I will describe how the plasma community is using the latest high performance computing facilities to develop and refine our models of the nonlinear, multiscale plasma dynamics, and how recent advances in experimental diagnostics are allowing us to directly test and validate these models at an unprecedented level.

276

Ceramics for fusion applications  

SciTech Connect

Ceramics are required for a variety of uses in both near-term fusion devices and in commercial powerplants. These materials must retain adequate structural and electrical properties under conditions of neutron, particle, and ionizing irradiation; thermal and applied stresses; and physical and chemical sputtering. Ceramics such as Al/sub 2/O/sub 3/, MgAl/sub 2/O/sub 4/, BeO, Si/sub 3/N/sub 4/ and SiC are currently under study for fusion applications, and results to date show widely-varying response to the fusion environment. Materials can be identified today which will meet initial operating requirements, but improvements in physical properties are needed to achieve satisfactory lifetimes for critical applications.

Clinard, F.W. Jr.

1986-01-01

277

Massachusetts Institute of Technology Plasma Fusion Center  

NASA Astrophysics Data System (ADS)

This report discusses the following topics on fusion energy: cold fusion; alcator confinement experiments; applied plasma physics research; fusion systems; coherent electromagnetic wave generation; and fusion technology and engineering.

1989-07-01

278

Intense fusion neutron sources  

NASA Astrophysics Data System (ADS)

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 1015-1021 neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 1020 neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

Kuteev, B. V.; Goncharov, P. R.; Sergeev, V. Yu.; Khripunov, V. I.

2010-04-01

279

Intense fusion neutron sources  

SciTech Connect

The review describes physical principles underlying efficient production of free neutrons, up-to-date possibilities and prospects of creating fission and fusion neutron sources with intensities of 10{sup 15}-10{sup 21} neutrons/s, and schemes of production and application of neutrons in fusion-fission hybrid systems. The physical processes and parameters of high-temperature plasmas are considered at which optimal conditions for producing the largest number of fusion neutrons in systems with magnetic and inertial plasma confinement are achieved. The proposed plasma methods for neutron production are compared with other methods based on fusion reactions in nonplasma media, fission reactions, spallation, and muon catalysis. At present, intense neutron fluxes are mainly used in nanotechnology, biotechnology, material science, and military and fundamental research. In the near future (10-20 years), it will be possible to apply high-power neutron sources in fusion-fission hybrid systems for producing hydrogen, electric power, and technological heat, as well as for manufacturing synthetic nuclear fuel and closing the nuclear fuel cycle. Neutron sources with intensities approaching 10{sup 20} neutrons/s may radically change the structure of power industry and considerably influence the fundamental and applied science and innovation technologies. Along with utilizing the energy produced in fusion reactions, the achievement of such high neutron intensities may stimulate wide application of subcritical fast nuclear reactors controlled by neutron sources. Superpower neutron sources will allow one to solve many problems of neutron diagnostics, monitor nano-and biological objects, and carry out radiation testing and modification of volumetric properties of materials at the industrial level. Such sources will considerably (up to 100 times) improve the accuracy of neutron physics experiments and will provide a better understanding of the structure of matter, including that of the neutron itself.

Kuteev, B. V. [Russian Research Centre Kurchatov Institute (Russian Federation); Goncharov, P. R.; Sergeev, V. Yu. [St. Petersburg State Polytechnic University (Russian Federation); Khripunov, V. I. [Russian Research Centre Kurchatov Institute (Russian Federation)

2010-04-15

280

Fusion cross-sections for inertial fusion energy  

Microsoft Academic Search

The application of selective resonant tunneling model is extended from d 1 t fusion to other light nucleus fusion reactions, such as d 1 d fusion and d 1 3 He. In contrast to traditional formulas, the new formula for the cross-section needs only a few parameters to fit the experimental data in the energy range of interest. The features

XING ZHONG LI; BIN LIU; SI CHEN; QING MING WEI; HEINRICH HORA

2004-01-01

281

Osteoclast Fusion is Based on Heterogeneity Between Fusion Partners.  

PubMed

Bone-resorbing osteoclasts are formed through fusion of mononucleated precursors. Their choice of partners during the fusion process remains unclear. We hypothesized that osteoclasts are selective in their choice of fusion partner and that this selectivity is based on heterogeneity among the cells with respect to their maturation stage and their expression and cellular organization of fusion factors. Support for this hypothesis was found from immunofluorescence staining of the osteoclast fusion factors CD47, dendritic cell-specific transmembrane protein (DC-STAMP), and syncytin-1. These stainings revealed heterogeneous localization patterns of all three factors within a given culture of osteoclasts. CD47 was found to be localized primarily in small osteoclasts and preosteoclasts, which were also positive for DC-STAMP but negative for cathepsin K expression. A role of CD47 in the early osteoclast fusion steps was also suggested from experiments with a CD47 blocking antibody, which resulted in an inhibition of the fusion of small osteoclasts. Conversely, blocking of connexin 43 affected the fusion of larger osteoclasts with four or more nuclei. The suggestion that different fusion factors function at different stages of osteoclast fusion supports the idea of heterogeneity in the osteoclast population; our results suggest that osteoclast fusion is indeed based on heterogeneity. Considering the in vivo environment in which osteoclasts develop and fuse, our findings seem very applicable and provide novel, important insight into key issues in bone and fusion research. PMID:24862648

Hobolt-Pedersen, Anne-Sofie; Delaissé, Jean-Marie; Søe, Kent

2014-07-01

282

Atomic data for fusion  

SciTech Connect

This report provides a handbook of recommended cross-section and rate-coefficient data for inelastic collisions between hydrogen, helium and lithium atoms, molecules and ions, and encompasses more than 400 different reactions of primary interest in fusion research. Published experimental and theoretical data have been collected and evaluated, and the recommended data are presented in tabular, graphical and parametrized form. Processes include excitation and spectral line emission, charge exchange, ionization, stripping, dissociation and particle interchange reactions. The range of collision energies is appropriate to applications in fusion-energy research.

Hunter, H.T.; Kirkpatrick, M.I.; Alvarez, I.; Cisneros, C.; Phaneuf, R.A. (eds.) [eds.; Barnett, C.F.

1990-07-01

283

Fusion for Space Propulsion  

NASA Technical Reports Server (NTRS)

The need for fusion propulsion for interplanetary flights is discussed. For a propulsion system, there are three important system attributes: (1) The absolute amount of energy available, (2) the propellant exhaust velocity, and (3) the jet power per unit mass of the propulsion system (specific power). For efficient and affordable human exploration of the solar system, propellant exhaust velocity in excess of 100 km/s and specific power in excess of 10 kW/kg are required. Chemical combustion obviously cannot meet the requirement in propellant exhaust velocity. Nuclear fission processes typically result in producing energy in the form of heat that needs to be manipulated at temperatures limited by materials to about 2,800 K. Using the fission energy to heat a low atomic weight propellant produces propellant velocity of the order of 10 kinds. Alternatively the fission energy can be converted into electricity that is used to accelerate particles to high exhaust velocity. However, the necessary power conversion and conditioning equipment greatly increases the mass of the propulsion system. Fundamental considerations in waste heat rejection and power conditioning in a fission electric propulsion system place a limit on its jet specific power to the order of about 0.2 kW/kg. If fusion can be developed for propulsion, it appears to have the best of all worlds - it can provide the largest absolute amount of energy, the propellant exhaust velocity (> 100 km/s), and the high specific jet power (> 10 kW/kg). An intermediate step towards fusion propulsion might be a bimodal system in which a fission reactor is used to provide some of the energy to drive a fusion propulsion unit. There are similarities as well as differences between applying fusion to propulsion and to terrestrial electrical power generation. The similarities are the underlying plasma and fusion physics, the enabling component technologies, the computational and the diagnostics capabilities. These physics and engineering capabilities have been demonstrated for a fusion reactor gain (Q) of the order of unity (TFTR: 0.25, JET: 0.65, JT-60: Q(sub eq) approx. 1.25). These technological advances made it compelling for considering fusion for propulsion.

Thio, Y. C. Francis; Schmidt, George R.; Santarius, John F.; Turchi, Peter J.; Siemon, Richard E.; Rodgers, Stephen L. (Technical Monitor)

2002-01-01

284

Fusion welding process  

DOEpatents

A process for the fusion welding of nickel alloy steel members wherein a ferrite containing pellet is inserted into a cavity in one member and melted by a welding torch. The resulting weld nugget, a fusion of the nickel containing alloy from the members to be welded and the pellet, has a composition which is sufficiently low in nickel content such that ferrite phases occur within the weld nugget, resulting in improved weld properties. The steel alloys encompassed also include alloys containing carbon and manganese, considered nickel equivalents.

Thomas, Kenneth C. (Export, PA); Jones, Eric D. (Salem, PA); McBride, Marvin A. (Hempfield Township, Westmoreland County, PA)

1983-01-01

285

Fusion Energy Educational Web Site  

NSDL National Science Digital Library

This site is a collection of resources about nuclear fusion. It provides a large set of definitions for the terms most commonly used in fusion research, and a course developed in conjunction with the Contemporary Physics Education Project.

Laboratory, Princeton P.; Laboratory, Lawrence L.

2003-10-10

286

Fusion technology status and requirements  

SciTech Connect

This paper summarizes the status of fusion technology and discusses the requirements to be met in order to build a demonstration fusion plant. Strategies and programmatic considerations in pursuing engineering feasibility are also outlined.

Thomassen, K.I.

1982-01-26

287

Isolation of mesenchymal stem cells from bone marrow wastes of spinal fusion procedure (TLIF) for low back pain patients and preparation of bone dusts for transplantable autologous bone graft with a serum glue.  

PubMed

Low back pain and subsequent disabilities are common. A lumbar spinal fusion procedure is an effective treatment with autologous bone grafts, but harvesting the bone from the iliac crest is associated with risks of complications. New treatments using stem cells together with osteoconductive and otesoinductive materials have made the procedure safer, but the inconsistency of the amount of stem cells harvested from bone marrow aspirate still remains to be solved. This study reports that the bone dusts, usually discarded as surgical wastes during transforaminal lumbar interbody fusion procedure (TLIF procedure), yielded cells which had the characteristics of mesenchymal stem cells (MSCs) in vitro. The cells were positive for the MSC markers and were able to differentiate in osteogenic and adipogenic directions. The cells grew robustly in an osteoconductive material, Bolheal (serum glue), and also proliferated well in culture medium supplemented with autologous serum. Therefore, the bone dust is a good candidate for the alternative source of stem cells other than bone marrow aspirate to increase the safety of the TLIF procedure. PMID:20592461

Ichiyanagi, T; Anabuki, K; Nishijima, Y; Ono, H

2010-06-01

288

Possibility theory in information fusion  

Microsoft Academic Search

Possibility theory and the body of aggregation operations from fuzzy set theory provide some tools to address the problem of merging information coming from several sources. The approach to fusion is set-theoretic and the choice of conjunctive versus disjunctive fusion modes depends on assumptions on whether all sources are reliable or not. Quantified, prioritized and weighted fusion rules are described.

Didier Dubois; H. Prade

2000-01-01

289

Bead fusion in polystyrene foams  

Microsoft Academic Search

A quantitative technique has been developed to measure the extent of fusion between expanded beads in molded polystyrene foams. Experiments were conducted with ASTM D638 tensile test specimens that were molded under conditions to produce various levels of bead fusion in the foam. The tensile properties of the foam for various levels of bead fusion were measured according to ASTM

J. Rossacci; S. Shivkumar

2003-01-01

290

Objective image fusion performance measure  

Microsoft Academic Search

A measure for objectively assessing the pixel level fusion performance is defined. The proposed metric reflects the quality of visual information obtained from the fusion of input images and can be used to compare the performance of different image fusion algorithms. Experimental results clearly indicate that this metric is perceptually meaningful

C. S. Xydeas; V. Petrovic

2000-01-01

291

Physics in Action: Fusion Machines  

NSDL National Science Digital Library

This article from Physics Central provides a description of fusion machines and plasma power. The process and challenges to producing a sustained fusion reaction that could lead to electric power generation are explained. Current research being conducted with fusion machines is also presented along with links to additional information.

2007-04-26

292

Summary of inertial fusion sessions  

Microsoft Academic Search

Laser and ion beam inertial fusion research has made remarkable progress during the last two years. As a highlight of the 22nd IAEA Fusion Energy Conference among over 30 presentations the National Ignition Facility has been reported for completion as of 27 March 2009 to achieve the first fusion shot within 2010 or 2011 with a central ignition scheme. The

Kazuo A. Tanaka

2009-01-01

293

Economic potential of inertial fusion  

Microsoft Academic Search

Beyond the achievement of scientific feasibility, the key question for fusion energy is: does it have the economic potential to be significantly cheaper than fission and coal energy. If fusion has this high economic potential then there are compelling commercial and geopolitical incentives to accelerate the pace of the fusion program in the near term, and to install a global

Nuckolls

1984-01-01

294

Information integration for data fusion.  

National Technical Information Service (NTIS)

Data fusion has been identified by the Department of Defense as a critical technology for the U.S. defense industry. Data fusion requires combining expertise in two areas - sensors and information integration. Although data fusion is a rapidly growing are...

O. H. Bray

1997-01-01

295

Human-Centered Fusion Framework  

SciTech Connect

In recent years the benefits of fusing signatures extracted from large amounts of distributed and/or heterogeneous data sources have been largely documented in various problems ranging from biological protein function prediction to cyberspace monitoring. In spite of significant progress in information fusion research, there is still no formal theoretical framework for defining various types of information fusion systems, defining and analyzing relations among such types, and designing information fusion systems using a formal method approach. Consequently, fusion systems are often poorly understood, are less than optimal, and/or do not suit user needs. To start addressing these issues, we outline a formal humancentered fusion framework for reasoning about fusion strategies. Our approach relies on a new taxonomy for fusion strategies, an alternative definition of information fusion in terms of parameterized paths in signature related spaces, an algorithmic formalization of fusion strategies and a library of numeric and dynamic visual tools measuring the impact as well as the impact behavior of fusion strategies. Using a real case of intelligence analysis we demonstrate that the proposed framework enables end users to rapidly 1) develop and implement alternative fusion strategies, 2) understand the impact of each strategy, 3) compare the various strategies, and 4) perform the above steps without having to know the mathematical foundations of the framework. We also demonstrate that the human impact on a fusion system is critical in the sense that small changes in strategies do not necessarily correspond to small changes in results.

Posse, Christian; White, Amanda M.; Beagley, Nathaniel

2007-05-16

296

Wavelets and image fusion  

Microsoft Academic Search

This paper describes an approach to image fusion using the wavelet transform. When images are merged in wavelet space, we can process different frequency ranges differently. For example, high frequency information from one image can be combined with lower frequency information from another, for performing edge enhancement. We have built a prototype system that allows experimentation with various wavelet array

Laure J. Chipman; Timothy M Orr; Lewis N. Graham

1995-01-01

297

Fission and fusion dynamics  

Microsoft Academic Search

In part I a unified macroscopic approach to the field of fission and heavy ion fusion is stressed. The principal degrees of freedom relevant to this field are described. In the equations of motion there are three types of terms (potential, dissipative and inertial terms). The principal features of the potential energy landscape are illustrated qualitatively by means of an

W. J. Swiatecki; S. Bjørnholm

1972-01-01

298

Inertial-confinement fusion  

Microsoft Academic Search

Reports that larger drivers, projected for the near future, are expected to compress the deuterium-tritium fuel to 1000 times its liquid density and achieve ignition of the fuel pellet. Vast amounts of fusion energy are released from the sun (and other stars) by natural thermonuclear processes that fuse atoms of lighter elements into atoms of heavier elements. In comparison to

J. H. Pitts; J. Hovingh; S. Walters

1982-01-01

299

Mars manned fusion spaceship  

NASA Technical Reports Server (NTRS)

Fusion Propulsion has an enormous potential for space exploration in the near future. In the twenty-first century, a usable and efficient fusion rocket will be developed and in use. Because of the great distance between other planets and Earth, efficient use of time, fuel, and payload is essential. A nuclear spaceship would provide greater fuel efficiency, less travel time, and a larger payload. Extended missions would give more time for research, experiments, and data acquisition. With the extended mission time, a need for an artificial environment exists. The topics of magnetic fusion propulsion, living modules, artificial gravity, mass distribution, space connection, and orbital transfer to Mars are discussed. The propulsion system is a magnetic fusion reactor based on a tandem mirror design. This allows a faster, shorter trip time and a large thrust to weight ratio. The fuel proposed is a mixture of deuterium and helium-3. Helium-3 can be obtained from lunar mining. There will be minimal external radiation from the reactor resulting in a safe, efficient propulsion system.

Hedrick, James; Buchholtz, Brent; Ward, Paul; Freuh, Jim; Jensen, Eric

1991-01-01

300

Bubble fusion: Preliminary estimates  

SciTech Connect

The collapse of a gas-filled bubble in disequilibrium (i.e., internal pressure {much_lt} external pressure) can occur with a significant focusing of energy onto the entrapped gas in the form of pressure-volume work and/or acoustical shocks; the resulting heating can be sufficient to cause ionization and the emission of atomic radiations. The suggestion that extreme conditions necessary for thermonuclear fusion to occur may be possible has been examined parametrically in terms of the ratio of initial bubble pressure relative to that required for equilibrium. In this sense, the disequilibrium bubble is viewed as a three-dimensional ``sling shot`` that is ``loaded`` to an extent allowed by the maximum level of disequilibrium that can stably be achieved. Values of this disequilibrium ratio in the range 10{sup {minus}5}--10{sup {minus}6} are predicted by an idealized bubble-dynamics model as necessary to achieve conditions where nuclear fusion of deuterium-tritium might be observed. Harmonic and aharmonic pressurizations/decompressions are examined as means to achieve the required levels of disequilibrium required to create fusion conditions. A number of phenomena not included in the analysis reported herein could enhance or reduce the small levels of nuclear fusions predicted.

Krakowski, R.A.

1995-02-01

301

Multisensor data fusion  

Microsoft Academic Search

Multisensor data fusion refers to the acquisition, processing and synergistic combination of information gathered by various knowledge sources and sensors to provide a better understanding of a phenomenon. It is a fascinating and rapidly evolving field that has generated a lot of excitement in the research and development community. These concepts are being applied to a wide variety of fields

P. K. Varshney

1997-01-01

302

Compact fusion reactors  

SciTech Connect

Compact, high-power-density approaches to fusion power are proposed to improve economic viability through the use of less-advanced technology in systems of considerably reduced scale. The rationale for and the means by which these systems can be achieved are discussed, as are unique technological problems.

Krakowski, R.A.; Hagenson, R.L.

1983-01-01

303

Fusion gamma diagnostics  

SciTech Connect

Nuclear reactions of interest in fusion research often possess a branch yielding prompt emission of gamma radiation in excess of 15 MeV which can be exploited to provide a new fusion reaction diagnostic having applications similar to conventional neutron emission measurements. Conceptual aspects of fusion gamma diagnostics are discussed with emphasis on application to the Tokamak Fusion Test Reactor (TFTR) during deuterium neutral beam heating of D--T and D--/sup 3/He plasmas. Recent measurements of the D (T, ..gamma..)/sup 5/He, D(/sup 3/He, ..gamma..)/sup 5/Li, and D(D, ..gamma..)/sup 4/He branching ratios at low center-of-mass energy (30--100 keV) and of the response of a large volume Ne226 detector for gamma detection in high neutron backgrounds are presented. Using a well-shielded Ne226 detector during 20 MW--120 kV deuterium beam heating of a tritium plasma in TFTR, the D(T, ..gamma..)/sup 5/He gamma signal level is estimated to be 3.5 x 10/sup 5/ cps.

Medley, S.S.; Cecil, F.E.; Cole, D.; Conway, M.A.; Wilkinson F.J. III

1985-05-01

304

Method of Fusion Welding.  

National Technical Information Service (NTIS)

An Author Certificate has been issued for a method of fusion welding in which the welding pool is treated by a traveling stray magnetic field. To increase the welding speed and improve the quality of welds by moving the molten metal of the welding pool al...

B. E. Paton S. L. Mandelberg V. K. Lebedev B. G. Sidorenko V. E. Lopata

1970-01-01

305

Fusion Pumped Laser.  

National Technical Information Service (NTIS)

The apparatus of this invention may comprise a system for generating laser radiation from a high-energy neutron source. The neutron source is a tokamak fusion reactor generating a long pulse of high-energy neutrons and having a temperature and magnetic fi...

D. S. Pappas

1987-01-01

306

Separating Fusion from Rivalry  

PubMed Central

Visual fusion is the process in which differing but compatible binocular information is transformed into a unified percept. Even though this is at the basis of binocular vision, the underlying neural processes are, as yet, poorly understood. In our study we therefore aimed to investigate neural correlates of visual fusion. To this end, we presented binocularly compatible, fusible (BF), and incompatible, rivaling (BR) stimuli, as well as an intermediate stimulus type containing both binocularly fusible and monocular, incompatible elements (BFR). Comparing BFR stimuli with BF and BR stimuli, respectively, we were able to disentangle brain responses associated with either visual fusion or rivalry. By means of functional magnetic resonance imaging, we measured brain responses to these stimulus classes in the visual cortex, and investigated them in detail at various retinal eccentricities. Compared with BF stimuli, the response to BFR stimuli was elevated in visual cortical areas V1 and V2, but not in V3 and V4 – implying that the response to monocular stimulus features decreased from V1 to V4. Compared to BR stimuli, the response to BFR stimuli decreased with increasing eccentricity, specifically within V3 and V4. Taken together, it seems that although the processing of exclusively monocular information decreases from V1 to V4, the processing of binocularly fused information increases from earlier to later visual areas. Our findings suggest the presence of an inhibitory neural mechanism which, depending on the presence of fusion, acts differently on the processing of monocular information.

Dechent, Peter; Forster, Clemens; von Steinbuchel, Nicole; Wustenberg, Torsten; Strasburger, Hans

2014-01-01

307

Status of inertial fusion  

SciTech Connect

The technology advancement to high-power beams has also given birth to new technologies. That class of Free Electron Lasers that employs rf linacs, synchrotrons, and storage rings - although the use the tools of High Energy Physics (HEP) - was developed well behind the kinetic energy frontier. The induction linac, however, is something of an exception; it was born directly from the needs of the magnetic fusion program, and was not motivated by a high-energy physics application. The heavy-ion approach to inertial fusion starts with picking from the rich menu of accelerator technologies those that have, ab initio, the essential ingredients needed for a power plant driver: multigap acceleration - which leads to reliability/lifetime; electrical efficiency; repetition rate; and beams that can be reliably focused over a suitably long distance. The report describes the programs underway in Heavy Ion Fusion Accelerator Research as well as listing expected advances in driver, target, and beam quality areas in the inertial fusion power program.

Keefe, D.

1987-04-01

308

Bubble fusion: Preliminary estimates  

NASA Astrophysics Data System (ADS)

The collapse of a gas-filled bubble in disequilibrium (i.e., internal pressure much less than external pressure) can occur with a significant focusing of energy onto the entrapped gas in the form of pressure-volume work and/or acoustical shocks; the resulting heating can be sufficient to cause ionization and the emission of atomic radiations. The suggestion that extreme conditions necessary for thermonuclear fusion to occur may be possible has been examined parametrically in terms of the ratio of initial bubble pressure relative to that required for equilibrium. In this sense, the disequilibrium bubble is viewed as a three-dimensional 'sling shot' that is 'loaded' to an extent allowed by the maximum level of disequilibrium that can stably be achieved. Values of this disequilibrium ratio in the range 10(exp -5) to 10(exp -6) are predicted by an idealized bubble-dynamics model as necessary to achieve conditions where nuclear fusion of deuterium-tritium might be observed. Harmonic and aharmonic pressurizations/decompressions are examined as means to achieve the required levels of disequilibrium required to create fusion conditions. A number of phenomena not included in the analysis reported herein could enhance or reduce the small levels of nuclear fusions predicted.

Krakowski, R. A.

309

Preoperative predictable factors for the occurrence of adjacent segment degeneration requiring second operation after spinal fusion at isolated L4-L5 level.  

PubMed

Study Design?Retrospective study. Objective?The purpose of this study was to clarify (1) the overall prevalence of radiologic and clinical adjacent segment disease (ASD), (2) the prevalence of radiologic ASD at cranial versus caudal adjacent segments, and (3) preoperative risk factors and preoperative radiologic features associated with radiologic disc degeneration of the cranial and caudal adjacent segments. Methods?A total of 154 patients who underwent posterior lumbar interbody fusion and screw-rod fixation at the L4-L5 level were retrospectively evaluated more than 2 years after surgery. We analyzed demographic factors and radiographic features. Special focus was preoperative radiographic features of patients who required additional surgery. These patients were studied to detect risk factors for clinical deterioration. Results?Of 154 patients, 103 (66.8%) showed radiologic degeneration at an adjacent segment after surgery-92 (59.7%) at the cranial adjacent segment and 61 (39.6%) at the caudal adjacent segment-and 10 patients (6.4%) required second operation because of radicular pain as well as severe back pain or spinal instability with back pain and neurologic deficits. Age, body mass index (BMI), and preexisting stenosis at the cranial adjacent segment were identified as important risk factors for clinical ASD requiring second operation. Conclusion?Age, BMI, and preexisting stenosis at the cranial adjacent segment were the most important risk factors for clinical ASD requiring a second operation. Careful consideration is warranted when these risk factors are present. PMID:24323740

Cho, Tae-Koo; Lim, Jae-Hyeon; Kim, Sang-Hyuk; Rhee, Woo-Tack; Kim, Woo-Jae; Ha, Seong-Il; Jang, Il-Tae

2014-07-01

310

Information exchanged between fusion tracker and other fusion functions  

NASA Astrophysics Data System (ADS)

The state of the art of tracking has matured and consequently, the priorities for improved performance and expanded or new processing capabilities have changed. Future directions in algorithm development in tracking and related data processing are not easy to predict with accuracy. The future priorities of development tasks predicted in this presentation are subjective; that is, simply the author's view. While there will continue to be algorithm development to improve many aspects of tracking, the emphasis is expected to change in favor of expanded or new capabilities. This paper concentrates on the interactions between the fusion tracker and the other fusion functions. Fusion is expected to have higher priority for algorithm development than tracking with single sensor data. The interactions between the fusion tracker and the other fusion functions are expected to be of special interest to achieve advanced fusion performance. To facilitate this discussion, the categories of the state of the art of tracking are expanded beyond the previous paper. Many aspects of single sensor, multiple target tracking have matured during the last 20 years but room for improvement remains. In contrast, fusion of data from multiple distributed sensors is far less mature and interest is expected to continue to increase. Many fusion systems pose challenges that are not of much concern in tracking with data from a single sensor and algorithm development of those aspects of fusion will continue to be needed. The capability of the many functions and users of the output of trackers needs to be improved and expanded. Consequently, an increase is expected in the need to improve in the interactions between the fusion tracker and the other fusion functions. Some of important interactions between the fusion tracker and the other fusion functions of a high performance multiple sensor fusion system are discussed and a dialogue on this topic is encouraged.

Drummond, Oliver E.

2011-09-01

311

Directions for improved fusion reactors  

SciTech Connect

Conceptual fusion reactor studies over the past 10 to 15 years have projected systems that may be too large, complex, and costly to be of commercial interest. One main direction for improved fusion reactors points towards smaller, higher-power-density approaches. First-order economic issues (i.e., unit direct cost and cost of electricity) are used to support the need for more compact fusion reactors. A generic fusion physics/engineering/costing model is used to provide a quantiative basis for these arguments for specific fusion concepts.

Krakowski, R.A.; Miller, R.L.; Delene, J.G.

1986-01-01

312

Accelerators for heavy ion fusion  

SciTech Connect

Large fusion devices will almost certainly produce net energy. However, a successful commercial fusion energy system must also satisfy important engineering and economic constraints. Inertial confinement fusion power plants driven by multi-stage, heavy-ion accelerators appear capable of meeting these constraints. The reasons behind this promising outlook for heavy-ion fusion are given in this report. This report is based on the transcript of a talk presented at the Symposium on Lasers and Particle Beams for Fusion and Strategic Defense at the University of Rochester on April 17-19, 1985.

Bangerter, R.O.

1985-10-01

313

Research on fusion neutron sources  

NASA Astrophysics Data System (ADS)

The use of fusion devices as powerful neutron sources has been discussed for decades. Whereas the successful route to a commercial fusion power reactor demands steady state stable operation combined with the high efficiency required to make electricity production economic, the alternative approach to advancing the use of fusion is free of many of complications connected with the requirements for economic power generation and uses the already achieved knowledge of Fusion physics and developed Fusion technologies. ``Fusion for Neutrons'' (F4N), has now been re-visited, inspired by recent progress achieved on comparably compact fusion devices, based on the Spherical Tokamak (ST) concept. Freed from the requirement to produce much more electricity than used to drive it, a fusion neutron source could be efficiently used for many commercial applications, and also to support the goal of producing energy by nuclear power. The possibility to use a small or medium size ST as a powerful or intense steady-state fusion neutron source (FNS) is discussed in this paper in comparison with the use of traditional high aspect ratio tokamaks. An overview of various conceptual designs of compact fusion neutron sources based on the ST concept is given and they are compared with a recently proposed Super Compact Fusion Neutron Source (SCFNS), with major radius as low as 0.5 metres but still able to produce several MW of neutrons in a steady-state regime.

Gryaznevich, M. P.

2012-06-01

314

Research on fusion neutron sources  

SciTech Connect

The use of fusion devices as powerful neutron sources has been discussed for decades. Whereas the successful route to a commercial fusion power reactor demands steady state stable operation combined with the high efficiency required to make electricity production economic, the alternative approach to advancing the use of fusion is free of many of complications connected with the requirements for economic power generation and uses the already achieved knowledge of Fusion physics and developed Fusion technologies. 'Fusion for Neutrons' (F4N), has now been re-visited, inspired by recent progress achieved on comparably compact fusion devices, based on the Spherical Tokamak (ST) concept. Freed from the requirement to produce much more electricity than used to drive it, a fusion neutron source could be efficiently used for many commercial applications, and also to support the goal of producing energy by nuclear power. The possibility to use a small or medium size ST as a powerful or intense steady-state fusion neutron source (FNS) is discussed in this paper in comparison with the use of traditional high aspect ratio tokamaks. An overview of various conceptual designs of compact fusion neutron sources based on the ST concept is given and they are compared with a recently proposed Super Compact Fusion Neutron Source (SCFNS), with major radius as low as 0.5 metres but still able to produce several MW of neutrons in a steady-state regime.

Gryaznevich, M. P. [Tokamak Solutions UK, Culham Science Centre, Abingdon, OXON, OX133DB (United Kingdom)

2012-06-19

315

The Need for Fusion Propulsion  

NASA Technical Reports Server (NTRS)

Fusion propulsion is inevitable if the human race remains dedicated to exploration of the solar system. There are fundamental reasons why fusion surpasses more traditional approaches to routine crewed missions to Mars, crewed missions to the outer planets, and deep space high speed robotic missions, assuming that reduced trip times, increased payloads, and higher available power are desired. A recent series of informal discussions were held among members from government, academia, and industry concerning fusion propulsion. We compiled a sufficient set of arguments for utilizing fusion in space. If the U.S. is to lead the effort and produce a working system in a reasonable amount of time, NASA must take the initiative, relying on, but not waiting for, DOE guidance. In this talk those arguments for fusion propulsion are presented, along with fusion enabled mission examples, fusion technology trade space, and a proposed outline for future efforts.

Cassibry, Jason

2005-01-01

316

Physics of magnetic confinement fusion  

NASA Astrophysics Data System (ADS)

Fusion is the energy source of the universe. The local conditions in the core of the Sun allow the transfer of mass into energy, which is finally released in the form of radiation. Technical fusion melts deuterons and tritons to helium releasing large amounts of energy per fusion process. Because of the conditions for fusion, which will be deduced, the fusion fuel is in the plasma state. Here we report on the confinement of fusion plasmas by magnetic fields. Different confinement concepts — tokamaks and stellarators — will be introduced and described. The first fusion reactor, ITER, and the most modern stellarator, Wendelstein 7-X, are under construction. Their basic features and objectives will be presented.

Wagner, F.

2013-06-01

317

Fusion pumped laser  

DOEpatents

The apparatus of this invention may comprise a system for generating laser radiation from a high-energy neutron source. The neutron source is a tokamak fusion reactor generating a long pulse of high-energy neutrons and having a temperature and magnetic field effective to generate a neutron flux of at least 10/sup 15/ neutrons/cm/sup 2//center dot/s. Conversion means are provided adjacent the fusion reactor at a location operable for converting the high-energy neutrons to an energy source with an intensity and energy effective to excite a preselected lasing medium. A lasing medium is spaced about and responsive to the energy source to generate a population inversion effective to support laser oscillations for generating output radiation. 2 figs., 2 tabs.

Pappas, D.S.

1987-07-31

318

Magnetically catalyzed fusion  

SciTech Connect

We calculate the reaction cross sections for the fusion of hydrogen and deuterium in strong magnetic fields as are believed to exist in the atmospheres of neutron stars. We find that in the presence of a strong magnetic field ({ital B}{approx_gt}10{sup 12} G), the reaction rates are many orders of magnitude higher than in the unmagnetized case. The fusion of both protons and deuterons is important over a neutron star{close_quote}s lifetime for ultrastrong magnetic fields ({ital B}{approximately}10{sup 16} G). The enhancement may have dramatic effects on thermonuclear runaways and bursts on the surfaces of neutron stars. {copyright} {ital 1996 The American Physical Society.}

Heyl, J.S.; Hernquist, L. [Lick Observatory, University of California, Santa Cruz, California 95064 (United States)] [Lick Observatory, University of California, Santa Cruz, California 95064 (United States)

1996-11-01

319

Tokamak fusion power reactors  

Microsoft Academic Search

The major parameters and corresponding economic characteristics of a representative class of commercial Tokamak fusion power reactors are examined as a function of four major design parameters: plasma beta-t, toroidal magnetic field strength, first-wall lifetime, and power output. It is shown that for beta-t greater than or equal to 0.06, the minimum cost of energy is obtained for toroidal field

W. M. Stacey Jr.; M. A. Abdou

1978-01-01

320

Inertial Confinement fusion targets  

NASA Technical Reports Server (NTRS)

Inertial confinement fusion (ICF) targets are made as simple flat discs, as hollow shells or as complicated multilayer structures. Many techniques were devised for producing the targets. Glass and metal shells are made by using drop and bubble techniques. Solid hydrogen shells are also produced by adapting old methods to the solution of modern problems. Some of these techniques, problems, and solutions are discussed. In addition, the applications of many of the techniques to fabrication of ICF targets is presented.

Hendricks, C. D.

1982-01-01

321

Modular Aneutronic Fusion Engine  

SciTech Connect

NASA's JUNO mission will arrive at Jupiter in July 2016, after nearly five years in space. Since operational costs tend to rise with mission time, minimizing such times becomes a top priority. We present the conceptual design for a 10MW aneutronic fusion engine with high exhaust velocities that would reduce transit time for a Jupiter mission to eighteen months and enable more challenging exploration missions in the solar system and beyond. __________________________________________________

Gary Pajer, Yosef Razin, Michael Paluszek, A.H. Glasser and Samuel Cohen

2012-05-11

322

Teachers Debate Cold Fusion  

NASA Astrophysics Data System (ADS)

What follows is a collection of messages about cold fusion from teachers. The messages were posted on the internet discussion list, Phys-L, or were sent to me in private. They illustrate a wide range of opinion. Phys-L is a list dedicated to learning and teaching physics with 700 subscribers from over 35 countries, the majority of whom are physics educators. <>.

Kowalski, Ludwik

2005-12-01

323

Sensor data fusion  

Microsoft Academic Search

This paper reviews some knowledge representation approaches devoted to the sensor fusion problem, as encountered whenever images, signals, text must be combined to provide the input to a controller or to an inference procedure. The basic steps involved in the derivation of the knowledge representation scheme, are:(A)locate a representation, based on exogeneous context information(B)compare two representations to find out if

Louis-françois Pau

1988-01-01

324

Fusion development and technology  

SciTech Connect

This report discusses the following: superconducting magnet technology; high field superconductors; advanced magnetic system and divertor development; poloidal field coils; gyrotron development; commercial reactor studies--aries; ITER physics: alpha physics and alcator R D for ITER; lower hybrid current drive and heating in the ITER device; ITER superconducting PF scenario and magnet analysis; ITER systems studies; and safety, environmental and economic factors in fusion development.

Montgomery, D.B.

1992-01-01

325

Wrist fusion versus limited carpal fusion in advanced kienbock's disease  

PubMed Central

We treated 18 patients with advanced Kienbock's disease surgically. Six had total wrist fusions and 12 had limited carpal fusions. The average age was 39.6 yrs and the average follow up was 61.8 months and 66.8 months respectively. The visual analogue pain scores, the patient satisfaction scores and the SF 12 were better in the total wrist fusion group. The DASH (Disabilities of the Arm, Shoulder and Hand) scores, the range of movement and the grip strengths were better in the limited carpal fusions group but this was not statistically significant. Four patients with limited carpal fusions had a non-union that required revising. We believe that total wrist fusion should be offered earlier to patients with advanced stages of the disease, as there are less surgical failures, more satisfied patients, better post operative pain scores and consistent long-term results with less potential for further deterioration with time as compared to other treatment methods.

Trail, I. A.; Stanley, J. K.

2005-01-01

326

Stabilized Spheromak Fusion Reactors  

SciTech Connect

The U.S. fusion energy program is focused on research with the potential for studying plasmas at thermonuclear temperatures, currently epitomized by the tokamak-based International Thermonuclear Experimental Reactor (ITER) but also continuing exploratory work on other plasma confinement concepts. Among the latter is the spheromak pursued on the SSPX facility at LLNL. Experiments in SSPX using electrostatic current drive by coaxial guns have now demonstrated stable spheromaks with good heat confinement, if the plasma is maintained near a Taylor state, but the anticipated high current amplification by gun injection has not yet been achieved. In future experiments and reactors, creating and maintaining a stable spheromak configuration at high magnetic field strength may require auxiliary current drive using neutral beams or RF power. Here we show that neutral beam current drive soon to be explored on SSPX could yield a compact spheromak reactor with current drive efficiency comparable to that of steady state tokamaks. Thus, while more will be learned about electrostatic current drive in coming months, results already achieved in SSPX could point to a productive parallel development path pursuing auxiliary current drive, consistent with plans to install neutral beams on SSPX in the near future. Among possible outcomes, spheromak research could also yield pulsed fusion reactors at lower capital cost than any fusion concept yet proposed.

Fowler, T

2007-04-03

327

Fusion gamma diagnostics  

SciTech Connect

Nuclear reactions of interest in fusion research often possess a branch that yields prompt emission of gamma radiation in excess of 15 MeV. This branch can be exploited to provide a new fusion reaction diagnostic having applications similar to conventional neutron emission measurements. Conceptual aspects of fusion gamma diagnostics are discussed with emphasis on application to TFTR during deuterium neutral beam heating of D-T and D-/sup 3/He plasmas. Recent measurements of the D(T, ..gamma..)/sup 5/He, D(/sup 3/He, ..gamma..)/sup 5/Li, and D(D, ..gamma..)/sup 4/He branching ratios at low center-of-mass energy (30 to 100 keV) and of the response of a large volume Ne226 detector for gamma detection in high neutron backgrounds are presented. For a well-shielded Ne226 detector, the D(T, ..gamma..)/sup 5/ He gamma signal level during 20 MW to 120 keV deuterium neutral beam heating of a TFTR tritium plasma was estimated to be 3.5 x 10/sup 5/ CPS.

Medley, S.S.; Cecil, F.E.; Cole, D.; Conway, M.A.; Wilkinson, F.J. III

1984-12-01

328

COLLABORATIVE: FUSION SIMULATION PROGRAM  

SciTech Connect

New York University, Courant Institute of Mathematical Sciences, participated in the ���¢��������Fusion Simulation Program (FSP) Planning Activities���¢������� [http://www.pppl.gov/fsp], with C.S. Chang as the institutional PI. FSP���¢��������s mission was to enable scientific discovery of important new plasma phenomena with associated understanding that emerges only upon integration. This requires developing a predictive integrated simulation capability for magnetically-confined fusion plasmas that are properly validated against experiments in regimes relevant for producing practical fusion energy. Specific institutional goal of the New York University was to participate in the planning of the edge integrated simulation, with emphasis on the usage of large scale HPCs, in connection with the SciDAC CPES project which the PI was leading. New York University successfully completed its mission by participating in the various planning activities, including the edge physics integration, the edge science drivers, and the mathematical verification. The activity resulted in the combined report that can be found in http://www.pppl.gov/fsp/Overview.html. Participation and presentations as part of this project are listed in a separation file.

Chang, Choong Seock

2012-06-05

329

Fusion for neutrons: A realisable fusion neutron source  

Microsoft Academic Search

For 60 years fusion research has been focused on Fusion for Energy (F4E) as the ultimate carbon-free solution to the world's energy problems. It is proving a worthy but difficult task. However it is relatively easy to produce high-energy fusion neutrons. The many potential applications of a 14MeV neutron source are outlined, and a range of existing designs for such

A Sykes; M. P. Gryaznevich; G Voss; D. Kingham; B. Kuteev

2011-01-01

330

Fusion for Neutrons: A Realizable Fusion Neutron Source  

Microsoft Academic Search

For 60 years, fusion research has been focused on fusion for energy as the ultimate carbon-free solution to the world's energy problems. It is proving a worthy but difficult task. However, it is relatively easy to produce high-energy fusion neutrons. The many potential applications of a 14-MeV neutron source are outlined, and a range of existing designs for such a

A. Sykes; M. P. Gryaznevich; G. Voss; D. Kingham; B. Kuteev

2012-01-01

331

Hyphal homing, fusion and mycelial interconnectedness  

Microsoft Academic Search

Hyphal fusion is a ubiquitous phenomenon in filamentous fungi. Although morphological aspects of hyphal fusion during vegetative growth are well described, molecular mechanisms associated with self-signaling and the cellular machinery required for hyphal fusion are just beginning to be revealed. Genetic analyses suggest that signal transduction pathways are conserved between mating cell fusion in Saccharomyces cerevisiae and vegetative hyphal fusion

N. Louise Glass; Carolyn Rasmussen; M. Gabriela Roca; Nick D. Read

2004-01-01

332

Sensor fusion for synthetic vision  

NASA Technical Reports Server (NTRS)

Display methodologies are explored for fusing images gathered by millimeter wave sensors with images rendered from an on-board terrain data base to facilitate visually guided flight and ground operations in low visibility conditions. An approach to fusion based on multiresolution image representation and processing is described which facilitates fusion of images differing in resolution within and between images. To investigate possible fusion methods, a workstation-based simulation environment is being developed.

Pavel, M.; Larimer, J.; Ahumada, A.

1991-01-01

333

Economic potential of inertial fusion  

SciTech Connect

Beyond the achievement of scientific feasibility, the key question for fusion energy is: does it have the economic potential to be significantly cheaper than fission and coal energy. If fusion has this high economic potential then there are compelling commercial and geopolitical incentives to accelerate the pace of the fusion program in the near term, and to install a global fusion energy system in the long term. Without this high economic potential, fusion's success depends on the failure of all alternatives, and there is no real incentive to accelerate the program. If my conjectures on the economic potential of inertial fusion are approximately correct, then inertial fusion energy's ultimate costs may be only half to two-thirds those of advanced fission and coal energy systems. Relative cost escalation is not assumed and could increase this advantage. Both magnetic and inertial approaches to fusion potentially have a two-fold economic advantage which derives from two fundamental properties: negligible fuel costs and high quality energy which makes possible more efficient generation of electricity. The wining approach to fusion may excel in three areas: electrical generating efficiency, minimum material costs, and adaptability to manufacture in automated factories. The winning approach must also rate highly in environmental potential, safety, availability factor, lifetime, small 0 and M costs, and no possibility of utility-disabling accidents.

Nuckolls, J.H.

1984-04-01

334

Spectral tetris fusion frame constructions  

NASA Astrophysics Data System (ADS)

A fusion frame is a collection of subspaces in a Hilbert space, generalizing the idea of a frame for signal representation. A tool to construct fusion frames is the spectral tetris algorithm, a flexible and elementary method to construct unit norm frames with a given frame operator having all of its eigenvalues greater than or equal to two. We discuss how spectral tetris can be used to construct fusion frames with prescribed eigenvalues for its fusion frame operator and with prescribed dimensions for its subspaces.

Casazza, Peter G.; Fickus, Matthew; Heinecke, Andreas; Wang, Yang; Zhou, Zhengfang

2011-09-01

335

The path to fusion power†  

PubMed Central

The promise, status and challenges of developing fusion power are outlined. The key physics and engineering principles are described and recent progress quantified. As the successful demonstration of 16?MW of fusion in 1997 in the Joint European Torus showed, fusion works. The central issue is therefore to make it work reliably and economically on the scale of a power station. We argue that to meet this challenge in 30 years we must follow the aggressive programme known as the ‘Fast Track to Fusion’. This programme is described in some detail.

Smith, Chris Llewellyn; Cowley, Steve

2010-01-01

336

Economics of less invasive spinal surgery: an analysis of hospital cost differences between open and minimally invasive instrumented spinal fusion procedures during the perioperative period  

PubMed Central

Background There is great debate about the costs and benefits of technology-driven medical interventions such as instrumented lumbar fusion. With most analyses using charge data, the actual costs incurred by medical institutions performing these procedures are not well understood. The object of the current study was to examine the differences in hospital operating costs between open and minimally invasive spine surgery (MIS) during the perioperative period. Methods Data were collected in the form of a prospective registry from a community hospital after specific Institutional Review Board approval was obtained. The analysis included consecutive adult patients being surgically treated for degenerative conditions of the lumbar spine, with either an MIS or open approach for two-level instrumented lumbar fusion. Patient outcomes and costs were collected for the perioperative period. Hospital operating costs were grouped by hospitalization/operative procedure, transfusions, reoperations, and residual events (health care interactions). Results One hundred and one open posterior lumbar interbody fusion (Open group) and 109 MIS patients were treated primarily for stenosis coupled with instability (39.6% and 59.6%, respectively). Mean total hospital costs were $27,055.53 for the Open group and $24,320.16 for the MIS group. This represents a statistically significant cost savings of $2,825.37 (10.4% [95% confidence interval: $522.51–$5,128.23]) when utilizing MIS over traditional Open techniques. Additionally, residual events, complications, and blood transfusions were significantly more frequent in the Open group, compared to the MIS group. Conclusions/level of evidence Utilizing minimally invasive techniques for instrumented spinal fusion results in decreased hospital operating costs compared to similar open procedures in the early perioperative period. Additionally, patient benefits of minimally invasive techniques include significantly less blood loss, shorter hospital stays, lower complication rate, and a lower number of residual events. Long-term outcome comparisons are needed to evaluate the efficacy of the two treatments. Level of evidence: III Clinical relevance This work represents a true cost-of-operating comparison between open and MIS approaches for lumbar spine fusion, which has relevance to surgeons, hospitals and payers in medical decision-making.

Lucio, John C; VanConia, R Brent; DeLuzio, Kevin J; Lehmen, Jeffrey A; Rodgers, Jody A; Rodgers, WB

2012-01-01

337

Membrane fusion machines of paramyxoviruses: capture of intermediates of fusion  

PubMed Central

Peptides derived from heptad repeat regions adjacent to the fusion peptide and transmembrane domains of many viral fusion proteins form stable helical bundles and inhibit fusion specifically. Paramyxovirus SV5 fusion (F) protein-mediated fusion and its inhibition by the peptides N-1 and C-1 were analyzed. The temperature dependence of fusion by F suggests that thermal energy, destabilizing proline residues and receptor binding by the hemagglutinin–neuraminidase (HN) protein collectively contribute to F activation from a metastable native state. F-mediated fusion was reversibly arrested by low temperature or membrane-incorporated lipids, and the resulting F intermediates were characterized. N-1 inhibited an earlier F intermediate than C-1. Co-expression of HN with F lowered the temperature required to attain the N-1-inhibited intermediate, consistent with HN binding to its receptor stimulating a conformational change in F. C-1 bound and inhibited an intermediate of F that could be detected until a point directly preceding membrane merger. The data are consistent with C-1 binding a pre-hairpin intermediate of F and with helical bundle formation being coupled directly to membrane fusion.

Russell, Charles J.; Jardetzky, Theodore S.; Lamb, Robert A.

2001-01-01

338

EDITORIAL: The Nuclear Fusion Award The Nuclear Fusion Award  

NASA Astrophysics Data System (ADS)

The Nuclear Fusion Award ceremony for 2009 and 2010 award winners was held during the 23rd IAEA Fusion Energy Conference in Daejeon. This time, both 2009 and 2010 award winners were celebrated by the IAEA and the participants of the 23rd IAEA Fusion Energy Conference. The Nuclear Fusion Award is a paper prize to acknowledge the best distinguished paper among the published papers in a particular volume of the Nuclear Fusion journal. Among the top-cited and highly-recommended papers chosen by the Editorial Board, excluding overview and review papers, and by analyzing self-citation and non-self-citation with an emphasis on non-self-citation, the Editorial Board confidentially selects ten distinguished papers as nominees for the Nuclear Fusion Award. Certificates are given to the leading authors of the Nuclear Fusion Award nominees. The final winner is selected among the ten nominees by the Nuclear Fusion Editorial Board voting confidentially. 2009 Nuclear Fusion Award nominees For the 2009 award, the papers published in the 2006 volume were assessed and the following papers were nominated, most of which are magnetic confinement experiments, theory and modeling, while one addresses inertial confinement. Sabbagh S.A. et al 2006 Resistive wall stabilized operation in rotating high beta NSTX plasmas Nucl. Fusion 46 635-44 La Haye R.J. et al 2006 Cross-machine benchmarking for ITER of neoclassical tearing mode stabilization by electron cyclotron current drive Nucl. Fusion 46 451-61 Honrubia J.J. et al 2006 Three-dimensional fast electron transport for ignition-scale inertial fusion capsules Nucl. Fusion 46 L25-8 Ido T. et al 2006 Observation of the interaction between the geodesic acoustic mode and ambient fluctuation in the JFT-2M tokamak Nucl. Fusion 46 512-20 Plyusnin V.V. et al 2006 Study of runaway electron generation during major disruptions in JET Nucl. Fusion 46 277-84 Pitts R.A. et al 2006 Far SOL ELM ion energies in JET Nucl. Fusion 46 82-98 Berk H.L. et al 2006 Explanation of the JET n = 0 chirping mode Nucl. Fusion 46 S888-97 Urano H. et al 2006 Confinement degradation with beta for ELMy HH-mode plasmas in JT-60U tokamak Nucl. Fusion 46 781-7 Izzo V.A. et al 2006 A numerical investigation of the effects of impurity penetration depth on disruption mitigation by massive high-pressure gas jet Nucl. Fusion 46 541-7 Inagaki S. et al 2006 Comparison of transient electron heat transport in LHD helical and JT-60U tokamak plasmas Nucl. Fusion 46 133-41 Watanabe T.-H. et al 2006 Velocity-space structures of distribution function in toroidal ion temperature gradient turbulence Nucl. Fusion 46 24-32 2010 Nuclear Fusion Award nominees For the 2010 award, the papers published in the 2007 volume were assessed and the following papers were nominated, all of which are magnetic confinement experiments and theory. Rice J.E. et al 2007 Inter-machine comparison of intrinsic toroidal rotation in tokamaks Nucl. Fusion 47 1618-24 Lipschultz B. et al 2007 Plasma-surface interaction, scrape-off layer and divertor physics: implications for ITER Nucl. Fusion 47 1189-205 Loarer T. et al 2007 Gas balance and fuel retention in fusion devices Nucl. Fusion 47 1112-20 Garcia O.E et al 2007 Fluctuations and transport in the TCV scrape-off layer Nucl. Fusion 47 667-76 Zonca F. et al 2007 Electron fishbones: theory and experimental evidence Nucl. Fusion 47 1588-97 Maggi C.F. et al 2007 Characteristics of the H-mode pedestal in improved confinement scenarios in ASDEX Upgrade, DIII-D, JET and JT-60U Nucl. Fusion 47 535-51 Yoshida M. et al 2007 Momentum transport and plasma rotation profile in toroidal direction in JT-60U L-mode plasmas Nucl. Fusion 47 856-63 Zohm H. et al 2007 Control of MHD instabilities by ECCD: ASDEX Upgrade results and implications for ITER Nucl. Fusion 47 228-32 Snyder P.B. et al 2007 Stability and dynamics of the edge pedestal in the low collisionality regime: physics mechanisms for steady-state ELM-free operation Nucl. Fusion 47 961-8 Urano H. et al 2007 H-mode pedestal structure in the variation of toroidal rotation and toroidal f

Kikuchi, M.

2011-01-01

339

Fission and Fusion Game  

NSDL National Science Digital Library

In this activity, students play a board game where they learn the characteristics of and differences between fission and fusion, as well as the real world applications of these energy-releasing reactions. Reproducible game cards and and game board are included in the resource. The investigation supports material presented in chapter 3, "What Heats the Earth's Interior?" in the textbook, Energy flow, part of the Global System Science, an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

340

Fusion reactor pumped laser  

DOEpatents

A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam.

Jassby, Daniel L. (Princeton, NJ)

1988-01-01

341

Peregrinations on cold fusion  

SciTech Connect

Attention is focused on the possibility of resonance-enhanced deuteron Coulomb barrier penetration. Because of the many-body nature of the interactions of room-temperature deuterons diffusing through a lattice possessing deuterons in many of the interstitial positions, the diffusing deuterons can resonate on the atomic scale in the potential wells bounded by the ascending walls of adjacent Coulomb barriers and thereby penetrate the Coulomb barriers in a fashion vastly underestimated by two-body calculations in which wells for possible resonance are absent. Indeed, perhaps the lack of robust reproducibility in cold fusion originates from the narrowness of such transmission resonances. 4 refs., 1 fig.

Turner, L.

1989-01-01

342

Physics of Fusion Welding  

NASA Technical Reports Server (NTRS)

Applicabilities and limitations of three techniques analyzed. NASA technical memorandum discusses physics of electron-beam, gas/ tungsten-arc, and laser-beam welding. From comparison of capabilities and limitations of each technique with regard to various welding conditions and materials, possible to develop criteria for selecting best welding technique in specific application. All three techniques classified as fusion welding; small volume of workpiece melted by intense heat source. Heat source moved along seam, leaving in wake solid metal that joins seam edges together.

Nunes, A. C., Jr.

1986-01-01

343

Transportation of Tritiated Waste from Fusion Facilities.  

National Technical Information Service (NTIS)

This paper examines methods of handling tritiated waste from a fusion facility, concentrating on handling requirements specific to tritium. Gaseous effluent from a fusion reactor can currently be transported from a fusion facility in two forms /-/ as a ga...

K. M. Gruetzmacher R. V. Carlson J. R. Stencel R. A. P. Sissingh

1988-01-01

344

Cold fusion catalyzed by muons and electrons.  

National Technical Information Service (NTIS)

Two alternative methods have been suggested to produce fusion power at low temperature. The first, muon catalyzed fusion or MCF, uses muons to spontaneously catalyze fusion through the muon mesomolecule formation. Unfortunately, this method fails to gener...

R. M. Kulsrud

1990-01-01

345

Helium Find Thaws the Cold Fusion Trail.  

ERIC Educational Resources Information Center

Reported is a study of cold fusion in which trace amounts of helium, possible evidence of an actual fusion reaction, were found. Research methodology is detailed. The controversy over the validity of experimental results with cold fusion are reviewed. (CW)

Pennisi, E.

1991-01-01

346

General Atomics Fusion Group Educational Home Page  

NSDL National Science Digital Library

This site from the General Atomics Energy Group features a collection of educational resources on fusion. Both naturally occuring fusion and fusion as an energy source are included. Resources for teachers to use in the classroom are included.

2010-03-31

347

Magnetless magnetic fusion  

SciTech Connect

The authors propose a concept of thermonuclear fusion reactor in which the plasma pressure is balanced by direct gas-wall interaction in a high-pressure vessel. The energy confinement is achieved by means of the self-contained toroidal magnetic configuration sustained by an external current drive or charged fusion products. This field structure causes the plasma pressure to decrease toward the inside of the discharge and thus it should be magnetohydrodynamically stable. The maximum size, temperature and density profiles of the reactor are estimated. An important feature of confinement physics is the thin layer of cold gas at the wall and the adjacent transitional region of dense arc-like plasma. The burning condition is determined by the balance between these nonmagnetized layers and the current-carrying plasma. They suggest several questions for future investigation, such as the thermal stability of the transition layer and the possibility of an effective heating and current drive behind the dense edge plasma. The main advantage of this scheme is the absence of strong external magnets and, consequently, potentially cheaper design and lower energy consumption.

Beklemishev, A.D. [Univ. of Texas, Austin, TX (United States). Inst. for Fusion Studies]|[Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation); Tajima, T. [Univ. of Texas, Austin, TX (United States). Inst. for Fusion Studies

1994-02-01

348

Collaborations in fusion research  

SciTech Connect

This paper reviews current experimental collaborative efforts in the fusion community and extrapolates to operational scenarios for the Tokamak Physics Experiment (TPX) and the International Thermonuclear Experimental Reactor (ITER). Current requirements, available technologies and tools, and problems, issues and concerns are discussed. This paper specifically focuses on the issues that apply to experimental operational collaborations. Special requirements for other types of collaborations, such as theoretical or design and construction efforts, will not be addressed. Our current collaborative efforts have been highly successful, even though the tools in use will be viewed as primitive by tomorrow`s standards. An overview of the tools and technologies in today`s collaborations can be found in the first section of this paper. The next generation of fusion devices will not be primarily institutionally based, but will be national (TPX) and international (ITER) in funding, management, operation and in ownership of scientific results. The TPX will present the initial challenge of real-time remotely distributed experimental data analysis for a steady state device. The ITER will present new challenges with the possibility of several remote control rooms all participating in the real-time operation of the experimental device. A view to the future of remote collaborations is provided in the second section of this paper.

Barnes, D.; Davis, S.; Roney, P.

1995-01-01

349

Activity : Fusion Reactions  

NSDL National Science Digital Library

This activity gives students an opportunity to learn about the elements created in the cores of high-mass stars by fusion reactions. They will discover that all stars start by burning hydrogen and end up creating many heavier elements inside their cores, elements that will be released into space when it dies in a supernova explosion. Students associate a layer with an element that is being produced by the high-mass star. This will illustrate that as the temperature of the star increases with depth, the ash of each burning stage becomes the fuel for the next stage. Surrounding the core of iron nuclei is a layer of silicon fusion, then magnesium, then neon, then oxygen, then carbon, then helium, and lastly, in the relatively cool periphery of the core, hydrogen fuses into helium. Students will draw their own version of the onion-like nature of the core of a star based on the model and explain the process that occurs at each layer.

2007-12-12

350

Pulsed power fusion program update  

Microsoft Academic Search

The US Department of Energy has supported a substantial research program in Inertial Confinement Fusion (ICF) since the early 1970s. Over the ensuing 25 years, pulsed power approaches to inertial fusion have remained of interest primarily because of the high energy, efficiency, and relatively low cost of the technology when compared to the mainline ICF approach involving large glass lasers.

J. P. Quintenz; R. G. Adams; G. O. Allshouse; J. E. Bailey; D. D. Bloomquist; G. A. Chandler; R. S. Coats; D. L. Cook; M. E. Cuneo; C. Deeney; M. S. Derzon; M. P. Desjarlais; M. R. Douglas; D. L. Fehl; A. B. Filuk; T. A. Haill; D. L. Hanson; D. J. Johnson; M. L. Kiefer; J. S. Lash; R. J. Leeper; B. M. Marder; M. K. Matzen; D. H. McDaniel; E. J. McGuire; T. A. Mehlhorn; L. P. Mix; A. R. Moats; T. J. Nash; C. L. Olson; R. E. Olson; T. D. Pointon; J. L. Porter; C. L. Ruiz; T. W. L. Sanford; J. F. Seamen; D. B. Seidel; S. A. Slutz; R. B. Spielman; W. A. Stygar; M. A. Sweeney; R. A. Vesey; D. F. Wenger

1998-01-01

351

Civilian applications of laser fusion  

SciTech Connect

The commercial aspects of laser fusion were evaluated in an attempt to relate the end products (neutrons and energy) to significant commercial applications. We have found that by far the largest markets and highest payoffs for laser fusion are associated with electric power production. Hence, much of this report evaluates the prospects of producing commercial electricity with laser fusion. To this end, we have described in detail a new and promising laser fusion concept--the liquid lithium waterfall reactor. In addition, we have taken the most attractive features from our laser fusion studies and used them to compare laser fusion to other long-range sources of energy (breeder reactors and solar energy). It is our contention that all three sources of electrical energy should be developed to the point where the final selections are primarily based on economic competitiveness. The other potential applications of laser fusion (fissile fuel production, synthetic fuel production, actinide burning, and propulsion) are also discussed, and our preliminary plan for the engineering development of laser fusion is presented.

Maniscalco, J.; Blink, J.; Buntzen, R.; Hovingh, J.; Meier, W.; Monsler, M.; Walker, P.

1978-08-14

352

Objective Image Fusion Performance Characterisation  

Microsoft Academic Search

Image fusion as a way of combining multiple image signals into a single fused image has in recent years been extensively researched for a variety of multisensor applications. Choosing an optimal fusion approach for each application from the plethora of algorithms available however, remains a largely open issue. A small number of metrics proposed so far provide only a rough,

Vladimir S. Petrovic; Costas S. Xydeas

2005-01-01

353

Plasma Physics for Nuclear Fusion  

Microsoft Academic Search

The book focuses on the properties of gaseous plasmas needed in the attainment of controlled fusion reactions. The first five chapters develop the fundamentals of plasma physics and present the conditions of nuclear fusion reactions. The next four provide a magnetohydrodynamic description of plasmas, followed by four chapters that explain wave phenomena and instabilities by means of a kinetic model.

K. Miyamoto; Robert L. Dewar

1980-01-01

354

Nuclear Fusion Technology In Japan  

Microsoft Academic Search

This is a technological assessment of the status of nuclear fusion researah and development technology in Japan. The Japanese nuclear policy, vision, goals, and supporting organizational structure are reviewed. The supporting facilities of the Japanese Atomic Energy Re- search Institute (JAERI) are illustrated and described. Specific emphasis is placed on the JAERI Naka Fusion Research Establishment near Mito. New photographic

Floyd A Wyczalek

1990-01-01

355

Inhibition of Hendra Virus Fusion  

PubMed Central

Hendra virus (HeV) is a recently identified paramyxovirus that is fatal in humans and could be used as an agent of bioterrorism. The HeV receptor-binding protein (G) is required in order for the fusion protein (F) to mediate fusion, and analysis of the triggering/activation of HeV F by G should lead to strategies for interfering with this key step in viral entry. HeV F, once triggered by the receptor-bound G, by analogy with other paramyxovirus F proteins, undergoes multistep conformational changes leading to a six-helix bundle (6HB) structure that accomplishes fusion of the viral and cellular membranes. The ectodomain of paramyxovirus F proteins contains two conserved heptad repeat regions (HRN and HRC) near the fusion peptide and the transmembrane domains, respectively. Peptides derived from the HRN and HRC regions of F are proposed to inhibit fusion by preventing F, after the initial triggering step, from forming the 6HB structure that is required for fusion. HeV peptides have previously been found to be effective at inhibiting HeV fusion. However, we found that a human parainfluenza virus 3 F-peptide is more effective at inhibiting HeV fusion than the comparable HeV-derived peptide.

Porotto, M.; Doctor, L.; Carta, P.; Fornabaio, M.; Greengard, O.; Kellogg, G. E.; Moscona, A.

2006-01-01

356

Kaliski's explosive driven fusion experiments  

Microsoft Academic Search

An experiment performed by a group in Poland on the production of DD fusion neutrons by purely explosive means is discussed. A method for multiplying shock velocities ordinarily available from high explosives by a factor of ten is described, and its application to DD fusion experiments is discussed.

1979-01-01

357

Hypothesis management for information fusion  

Microsoft Academic Search

The efficient management of large collections of fusion hypotheses presents a critical challenge for scaling high-level information fusion systems to solve large problems. We motivate this challenge in the context of two Alphatech research projects, and discuss several partial solutions. A recurring theme is the exploitation of space-efficient, factored representations of multiple hypotheses to enable an efficient search for good

Eric K. Jones; Nikolaos Denis; Daniel Hunter

2003-01-01

358

Hypothesis management for information fusion  

Microsoft Academic Search

The efficient management of large collections of fusion hypotheses presents a critical challenge for scaling high-level information fusion systems to solve large problems. We motivate this challenge in the context of two ALPHATECH research projects, and discuss several partial solutions. A recurring theme is the exploitation of space-efficient, factored representations of multiple hypotheses to enable efficient search for good hypotheses.

Eric K. Jones; Nikolaos Denis; Daniel Hunter

2002-01-01

359

The status of cold fusion  

NASA Astrophysics Data System (ADS)

This report attempts to update the status of the phenomenon of cold fusion. The new field is continuing to grow as a variety of nuclear reactions are discovered to occur in a variety of chemical environments at modest temperatures. However, it must be cautioned that most scientists consider cold fusion as something akin to UFO's, ESP, and numerology.

Storms, E.

360

Glycoprotein interactions in paramyxovirus fusion  

PubMed Central

The Paramyxoviridae are enveloped, negative-stranded RNA viruses, some of which recognize sialic acid-containing receptors, while others recognize specific proteinaceous receptors. The major cytopathic effect of paramyxovirus infection is membrane fusion-induced syncytium formation. Paramyxoviruses are unusual in that the receptor-binding and fusion-promoting activities reside on two different spike structures, the attachment and fusion glycoproteins, respectively. For most paramyxoviruses, this distribution of functions requires a mechanism by which the two processes can be linked for the promotion of fusion. This is accomplished by a virus-specific interaction between the two proteins. An increasing body of evidence supports the notion that members of this family of viruses utilize this glycoprotein interaction in different ways in order to mediate the regulation of the fusion protein activation, depending on the type of receptor utilized by the virus.

Iorio, Ronald M; Melanson, Vanessa R; Mahon, Paul J

2009-01-01

361

Information integration for data fusion  

SciTech Connect

Data fusion has been identified by the Department of Defense as a critical technology for the U.S. defense industry. Data fusion requires combining expertise in two areas - sensors and information integration. Although data fusion is a rapidly growing area, there is little synergy and use of common, reusable, and/or tailorable objects and models, especially across different disciplines. The Laboratory-Directed Research and Development project had two purposes: to see if a natural language-based information modeling methodology could be used for data fusion problems, and if so, to determine whether this methodology would help identify commonalities across areas and achieve greater synergy. The project confirmed both of the initial hypotheses: that the natural language-based information modeling methodology could be used effectively in data fusion areas and that commonalities could be found that would allow synergy across various data fusion areas. The project found five common objects that are the basis for all of the data fusion areas examined: targets, behaviors, environments, signatures, and sensors. Many of the objects and the specific facts related to these objects were common across several areas and could easily be reused. In some cases, even the terminology remained the same. In other cases, different areas had their own terminology, but the concepts were the same. This commonality is important with the growing use of multisensor data fusion. Data fusion is much more difficult if each type of sensor uses its own objects and models rather than building on a common set. This report introduces data fusion, discusses how the synergy generated by this LDRD would have benefited an earlier successful project and contains a summary information model from that project, describes a preliminary management information model, and explains how information integration can facilitate cross-treaty synergy for various arms control treaties.

Bray, O.H.

1997-01-01

362

EDITORIAL: Stochasticity in fusion plasmas Stochasticity in fusion plasmas  

NASA Astrophysics Data System (ADS)

Structure formation and transport in stochastic plasmas is a topic of growing importance in many fields of plasma physics from astrophysics to fusion research. In particular, the possibility to control transport in the boundary of confined fusion plasmas by resonant magnetic perturbations has been investigated extensively during recent years. A major research achievement was finding that the intense transient particle and heat fluxes associated with edge localized modes (here type-I ELMs) in magnetically confined fusion plasmas can be mitigated or even suppressed by resonant magnetic perturbation fields. This observation opened up a possible scheme to avoid too large erosion and material damage by such transients in future fusion devices such as ITER. However, it is widely recognized that a more basic understanding is needed to extrapolate the results obtained in present experiments to future fusion devices. The 4th workshop on Stochasticity in Fusion Plasmas was held in Jülich, Germany, from 2 to 4 March 2009. This series of workshops aims at gathering fusion experts from various plasma configurations such as tokamaks, stellarators and reversed field pinches to exchange knowledge on structure formation and transport in stochastic fusion plasmas. The workshops have attracted colleagues from both experiment and theory and stimulated fruitful discussions about the basics of stochastic fusion plasmas. Important papers from the first three workshops in 2003, 2005 and 2007 have been published in previous special issues of Nuclear Fusion (stacks.iop.org/NF/44/i=6, stacks.iop.org/NF/46/i=4 and stacks.iop.org/NF/48/i=2). This special issue comprises contributions presented at the 4th SFP workshop, dealing with the main subjects such as formation of stochastic magnetic layers, energy and particle transport in stochastic magnetic fields, plasma response to external, non-axis-symmetric perturbations and last but not least application of resonant magnetic perturbations for ELM control and implications for ITER. The next workshop is planned for February/March 2011 in Jülich. For details see http://www.fz-juelich.de/sfp/. We hope that this special issue of Nuclear Fusion will further stimulate interest in the fascinating and important subject of stochasticity in fusion plasmas.

Unterberg, Bernhard

2010-03-01

363

Minimally invasive spine surgery in chronic low back pain patients.  

PubMed

Low back pain (LBP) is a common disorder with a lifetime prevalence of 85%. The pathophysiology of LBP can be various depending on the underlying problem. Only in about 10% of the patients specific underlying disease processes can be identified. Patients with scoliosis, spondylolisthesis, herniated discs, adjacent disc disease, disc degeneration, failed back surgery syndrome or pseudoartrosis all have symptoms of LBP in different ways. Chronic low back pain patients are advised to stay active, however, there is no strong evidence that exercise therapy is significantly different than other nonsurgical therapies. Not every patient with symptoms of LBP is an appropriate candidate for surgery. Even with thorough systematic reviews, no proof can be found for the benefit of surgery in patients with low back pain, without serious neurologic deficit. And subjects like psychologic and socio-demographic factors also seem to be influencing a patients perception of back pain, expectations of treatment, and outcomes of treatment. Open lumbar fusion procedures are typically lengthy procedures and require a long exposure, which may result in ischemic necrosis of the paraspinal musculature, atrophy, and prolonged back pain. Minimally invasive spine surgery needed to take care of a decrease in muscle injuries due to retraction and avoidance of disruption of the osseotendineous complex of the paraspinal muscles, especially the multifidus attachment to the spinous process and superior articular process. Therefore, effort has been made to develop percutaneous fusion, as well as fixation methods, which avoid the negative effects of open surgery. Several minimally invasive fusion strategies have been described, like anterior lumbar interbody fusion (ALIF), posterior lumbar interbody fusion (PLIF), transforaminal lumbar interbody fusion (TLIF) and two lateral approaches (XLIF and DLIF), all with pro's and con's compared to open surgery and each other. The effect of MIS of all type is that patients have less blood loss, faster postoperative ambulation, lower use of opioids, and shorter in hospital stay, which is nearly always significantly better than an open procedure. And most of the studies show a significant improvement of VAS leg-and back pain, Oswestry Disability Index and a high fusion rate, but most of the times not significantly different than the open counterpart. When it comes to cost-effectiveness there is a trend in favor of MIS, but to when we want to differentiate MIS from open surgery, comorbidities and complications significantly affect general and disease-specific outcome measures. In our opinion, the actual better outcome of minimal invasive surgery comes down to obtain a good cost-effectiveness study, provided that minimally invasive surgery has an equal or better clinical and radiologic outcome, given that socio-economic, demographic and psychological influencers are equal for both types of surgery. There are no studies done on the subject MIS and low back pain solely. Deriving answers from the difference in VAS back pain in MIS studies reveal a 100% improvement of back pain after surgery. But that does not imply that this procedure, which is still in its childhood, will be the solution to all low back pain patients. PMID:23877267

Spoor, A B; Öner, F C

2013-09-01

364

Microwave superheaters for fusion  

SciTech Connect

The microwave superheater uses the synchrotron radiation from a thermonuclear plasma to heat gas seeded with an alkali metal to temperatures far above the temperature of material walls. It can improve the efficiency of the Compact Fusion Advanced Rankine (CFAR) cycle described elsewhere in these proceedings. For a proof-of-principle experiment using helium, calculations show that a gas superheat ..delta..T of 2000/sup 0/K is possible when the wall temperature is maintained at 1000/sup 0/K. The concept can be scaled to reactor grade systems. Because of the need for synchrotron radiation, the microwave superheater is best suited for use with plasmas burning an advanced fuel such as D-/sup 3/He. 5 refs.

Campbell, R.B.; Hoffman, M.A.; Logan, B.G.

1987-10-16

365

Advanced spheromak fusion reactor  

SciTech Connect

The spheromak has no toroidal magnetic field coils or other structure along its geometric axis, and is thus more attractive than the leading magnetic fusion reactor concept, the tokamak. As a consequence of this and other attributes, the spheromak reactor may be compact and produce a power density sufficiently high to warrant consideration of a liquid `blanket` that breeds tritium, converts neutron kinetic energy to heat, and protects the reactor vessel from severe neutron damage. However, the physics is more complex, so that considerable research is required to learn how to achieve the reactor potential. Critical physics problems and possible ways of solving them are described. The opportunities and issues associated with a possible liquid wall are considered to direct future research.

Fowler, T.K. [California Univ., Berkeley, CA (United States). Dept. of Nuclear Engineering; Hooper, E.B. [Lawrence Livermore National Lab., CA (United States)

1996-06-19

366

Fusion reactor pumped laser  

DOEpatents

A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam. 10 figs.

Jassby, D.L.

1987-09-04

367

Fusion Power Demonstration III  

SciTech Connect

This is the third in the series of reports covering the Fusion Power Demonstration (FPD) design study. This volume considers the FPD-III configuration that incorporates an octopole end plug. As compared with the quadrupole end-plugged designs of FPD-I and FPD-II, this octopole configuration reduces the number of end cell magnets and shortens the minimum ignition length of the central cell. The end-cell plasma length is also reduced, which in turn reduces the size and cost of the end cell magnets and shielding. As a contiuation in the series of documents covering the FPD, this report does not stand alone as a design description of FPD-III. Design details of FPD-III subsystems that do not differ significantly from those of the FPD-II configuration are not duplicated in this report.

Lee, J.D. (ed.)

1985-07-01

368

Fusion pumped laser  

DOEpatents

Apparatus is provided for generating energy in the form of laser radiation. A tokamak fusion reactor is provided for generating a long, or continuous, pulse of high-energy neutrons. The tokamak design provides a temperature and a magnetic field which is effective to generate a neutron flux of at least 10.sup.15 neutrons/cm.sup.2.s. A conversion medium receives neutrons from the tokamak and converts the high-energy neutrons to an energy source with an intensity and an energy effective to excite a preselected lasing medium. The energy source typically comprises fission fragments, alpha particles, and radiation from a fission event. A lasing medium is provided which is responsive to the energy source to generate a population inversion which is effective to support laser oscillations for generating output radiation.

Pappas, Daniel S. (Los Alamos, NM)

1989-01-01

369

Soldier systems sensor fusion  

NASA Astrophysics Data System (ADS)

This paper addresses sensor fusion and its applications in emerging Soldier Systems integration and the unique challenges associated with the human platform. Technology that,provides the highest operational payoff in a lightweight warrior system must not only have enhanced capabilities, but have low power components resulting in order of magnitude reductions coupled with significant cost reductions. These reductions in power and cost will be achieved through partnership with industry and leveraging of commercial state of the art advancements in microelectronics and power sources. As new generation of full solution fire control systems (to include temperature, wind and range sensors) and target acquisition systems will accompany a new generation of individual combat weapons and upgrade existing weapon systems. Advanced lightweight thermal, IR, laser and video senors will be used for surveillance, target acquisition, imaging and combat identification applications. Multifunctional sensors will provide embedded training features in combat configurations allowing the soldier to 'train as he fights' without the traditional cost and weight penalties associated with separate systems. Personal status monitors (detecting pulse, respiration rate, muscle fatigue, core temperature, etc.) will provide commanders and highest echelons instantaneous medical data. Seamless integration of GPS and dead reckoning (compass and pedometer) and/or inertial sensors will aid navigation and increase position accuracy. Improved sensors and processing capability will provide earlier detection of battlefield hazards such as mines, enemy lasers and NBC (nuclear, biological, chemical) agents. Via the digitized network the situational awareness database will automatically be updated with weapon, medical, position and battlefield hazard data. Soldier Systems Sensor Fusion will ultimately establish each individual soldier as an individual sensor on the battlefield.

Brubaker, Kathryne M.

1998-08-01

370

Magnetized Liner Inertial Fusion  

NASA Astrophysics Data System (ADS)

The natural geometry for magnetically driven implosions is cylindrical, but cylindrical implosions require more radial convergence than spherical implosions due to reduced volume convergence. Fuel magnetization and preheat can ameliorate this problem by reducing conduction losses and the required compressive heating. Assuming a deuterium-tritium fuel preheated to 200-500 eV and magnetized with a 10T field, numerical simulations indicate that fusion conditions could be obtained by cylindrical liner implosions driven by the Z accelerator. According to the simulations the initial axial magnetic field is compressed to more than 100 MG, which inhibits thermal conduction and the escape of alpha particles. The inhibited thermal transport allows the fuel to reach temperatures exceeding 5 keV despite an implosion velocity of only 10 cm/?s. The final fuel density is about 1 g/cc, which is high enough to axially trap alpha particles for cylinders less than 1 cm long with a purely axial magnetic field. Analytic and numeric calculations indicate that the fuel can be heated to 200-500 eV with 3-10 kJ of green laser light, which could be provided by the Z-Beamlet laser. The Magneto-Rayleigh-Taylor instability poses the greatest threat to this approach to fusion. 2D numerical simulations indicate that the liner walls must have a substantial initial thickness (15-30% of the radius) to maintain integrity throughout the implosion. Z and Z Beamlet experiments are underway to test the various components of this concept.

Slutz, Stephen

2009-11-01

371

Poxvirus entry and membrane fusion  

SciTech Connect

The study of poxvirus entry and membrane fusion has been invigorated by new biochemical and microscopic findings that lead to the following conclusions: (1) the surface of the mature virion (MV), whether isolated from an infected cell or by disruption of the membrane wrapper of an extracellular virion, is comprised of a single lipid membrane embedded with non-glycosylated viral proteins; (2) the MV membrane fuses with the cell membrane, allowing the core to enter the cytoplasm and initiate gene expression; (3) fusion is mediated by a newly recognized group of viral protein components of the MV membrane, which are conserved in all members of the poxvirus family; (4) the latter MV entry/fusion proteins are required for cell to cell spread necessitating the disruption of the membrane wrapper of extracellular virions prior to fusion; and furthermore (5) the same group of MV entry/fusion proteins are required for virus-induced cell-cell fusion. Future research priorities include delineation of the roles of individual entry/fusion proteins and identification of cell receptors.

Moss, Bernard [Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-0445 (United States)]. E-mail: bmoss@nih.gov

2006-01-05

372

Future of Inertial Fusion Energy  

SciTech Connect

In the past 50 years, fusion R&D programs have made enormous technical progress. Projected billion-dollar scale research facilities are designed to approach net energy production. In this century, scientific and engineering progress must continue until the economics of fusion power plants improves sufficiently to win large scale private funding in competition with fission and non-nuclear energy systems. This economic advantage must be sustained: trillion dollar investments will be required to build enough fusion power plants to generate ten percent of the world's energy. For Inertial Fusion Energy, multi-billion dollar driver costs must be reduced by up to an order of magnitude, to a small fraction of the total cost of the power plant. Major cost reductions could be achieved via substantial improvements in target performance-both higher gain and reduced ignition energy. Large target performance improvements may be feasible through a combination of design innovations, e.g., ''fast ignition,'' propagation down density gradients, and compression of fusion fuel with a combination of driver and chemical energy. The assumptions that limit projected performance of fusion targets should be carefully examined. The National Ignition Facility will enable development and testing of revolutionary targets designed to make possible economically competitive fusion power plants.

Nuckolls, J H; Wood, L L

2002-09-04

373

Fission-fusion neutron source  

NASA Astrophysics Data System (ADS)

In order to meet the requirements of fusion power reactors and nuclear waste treatment, a concept of fission-fusion neutron source is proposed, which consists of a LiD assembly located in the heavy water region of the China Advanced Research Reactor. This assembly of LiD fuel rods will be irradiated with slow neutrons and will produce fusion neutrons in the central hole via the reaction 6Li(n, ?). More precisely, tritium ions with a high energy of 2.739 MeV will be produced in LiD by the impinging slow neutrons. The tritium ions will in turn bombard the deuterium ions present in the LiD assembly, which will induce fusion reaction and then the production of 14 MeV neutrons. The fusion reaction rate will increase with the accumulation of tritium in LiD by the reaction between tritium and deuteron recoils produced by the 14 MeV neutrons. When the concentration of tritium reaches 0.5 · 10 22 and the fraction of fusion reactions between tritium and deuteron recoils approaches 1, the 14 MeV neutron flux is doubled and redoubled, an so forth, approaching saturation in which the tritium produced at a time t is exhausted by the fusion reactions to keep constant the tritium concentration in LiD.

Yu, Jinnan; Yu, Gang

2009-04-01

374

Simulation Science for Fusion Plasmas  

NASA Astrophysics Data System (ADS)

The world fusion effort has recently entered a new age with the construction of ITER in Cadarache, France, which will be the first magnetic confinement fusion plasma experiment dominated by the self-heating of fusion reactions. In order to operate and control burning plasmas and future demo fusion reactors, an advanced ability for comprehensive computer simulations that are fully verified and validated against experimental data will be necessary. The ultimate goal is to develop the capability to predict reliably the behavior of plasmas in toroidal magnetic confinement devices on all relevant time and space scales. In addition to developing a sophisticated integrated simulation codes, directed advanced research in fusion physics, applied mathematics and computer science is envisaged. In this talk we review the basic strategy and main research efforts at the Department of Simulation Science of the National Institute for Fusion Science (NIFS)- which is the Inter University Institute and the coordinating Center of Excellence for academic fusion research in Japan. We overview a simulation research at NIFS, in particular relation to experiments in the Large Helical Device (LHD), the world's largest superconducting heliotron device, as a National Users' facility (see Motojima et al. 2003). Our main goal is understanding and systemizing the rich hierarchy of physical mechanisms in fusion plasmas, supported by exploring a basic science of complexity of plasma as a highly nonlinear, non-equilibrium, open system. The aim is to establish a simulation science as a new interdisciplinary field by fostering collaborative research in utilizing the large-scale supercomputer simulators. A concept of the hierarchy-renormalized simulation modelling will be invoked en route toward the LHD numerical test reactor. Finally, a perspective role is given on the ITER Broad Approach program at Rokkasho Center, as an integrated part of ITER and Development of Fusion Energy Agreement.

Skoric, M. M.; Sudo, S.

2008-07-01

375

FuzzyFusion: an application architecture for multisource information fusion  

NASA Astrophysics Data System (ADS)

The correlation of information from disparate sources has long been an issue in data fusion research. Traditional data fusion addresses the correlation of information from sources as diverse as single-purpose sensors to all-source multi-media information. Information system vulnerability information is similar in its diversity of sources and content, and in the desire to draw a meaningful conclusion, namely, the security posture of the system under inspection. FuzzyFusionTM, A data fusion model that is being applied to the computer network operations domain is presented. This model has been successfully prototyped in an applied research environment and represents a next generation assurance tool for system and network security.

Fox, Kevin L.; Henning, Ronda R.

2009-04-01

376

Economic analysis of fusion breeders  

SciTech Connect

This paper presents a study of the economic performance of Fission/Fusion Hybrid devices. This work takes fusion breeder cost estimates and applies methodology and cost factors used in the fission reactor programs to compare fusion breeders with Liquid Metal Fast Breeder Reactors (LMFBR). The results of the analysis indicate that the Hybrid will be in the same competitive range as proposed LMFBRs and have the potential to provide economically competitive power in a future of rising uranium prices. The sensitivity of the results to variations in key parameters is included.

Delene, J.G.

1985-01-01

377

Image fusion with guided filtering.  

PubMed

A fast and effective image fusion method is proposed for creating a highly informative fused image through merging multiple images. The proposed method is based on a two-scale decomposition of an image into a base layer containing large scale variations in intensity, and a detail layer capturing small scale details. A novel guided filtering-based weighted average technique is proposed to make full use of spatial consistency for fusion of the base and detail layers. Experimental results demonstrate that the proposed method can obtain state-of-the-art performance for fusion of multispectral, multifocus, multimodal, and multiexposure images. PMID:23372084

Li, Shutao; Kang, Xudong; Hu, Jianwen

2013-07-01

378

Advanced fusion concepts: project summaries  

SciTech Connect

This report contains descriptions of the activities of all the projects supported by the Advanced Fusion Concepts Branch of the Office of Fusion Energy, US Department of Energy. These descriptions are project summaries of each of the individual projects, and contain the following: title, principle investigators, funding levels, purpose, approach, progress, plans, milestones, graduate students, graduates, other professional staff, and recent publications. Information is given for each of the following programs: (1) reverse-field pinch, (2) compact toroid, (3) alternate fuel/multipoles, (4) stellarator/torsatron, (5) linear magnetic fusion, (6) liners, and (7) Tormac. (MOW)

None

1980-12-01

379

Fusion of Loops for Parallelism and Locality  

Microsoft Academic Search

Loop fusion improves data locality and re- duces synchronization in data-parallel applications. How - ever, loop fusion is not always legal. Even when legal, fusion may introduce loop-carried dependences which re- duce parallelism. In addition, performance losses result from cache conflicts in fused loops. We present new, sys- tematic techniques which: (1) allow fusion of loop nests in the presence

Naraig Manjikian; Tarek S. Abdelrahman

1995-01-01

380

Fusion of Loops for Parallelism and Locality  

Microsoft Academic Search

Abstract Loop fusion improves data locality and reduces synchronization in data-parallel applications. However, loop fusion is not always legal. Even when legal, fusion may introduce loop-carried dependences which prevent parallelism. In addition, performance losses result from cache conflicts in fused loops. In this paper, we present new techni ques to: (1) allow fusion of loop nests in the presence of

Naraig Manjikian; Tarek S. Abdelrahman

1997-01-01

381

Developments in inertial fusion energy and beam fusion at magnetic confinement  

Microsoft Academic Search

The 70-year anniversary of the first nuclear fusion reaction of hydrogen isotopes by Oliphant, Harteck, and Rutherford is an opportunity to realize how beam fusion is the path for energy production, including both branches, the magnetic confinement fusion and the inertial fusion energy (IFE). It is intriguing that Oliphant's basic concept for igniting controlled fusion reactions by beams has made

Heinrich Hora

2004-01-01

382

Fusion materials irradiations at MaRIE's fission fusion facility  

SciTech Connect

Los Alamos National Laboratory's proposed signature facility, MaRIE, will provide scientists and engineers with new capabilities for modeling, synthesizing, examining, and testing materials of the future that will enhance the USA's energy security and national security. In the area of fusion power, the development of new structural alloys with better tolerance to the harsh radiation environments expected in fusion reactors will lead to improved safety and lower operating costs. The Fission and Fusion Materials Facility (F{sup 3}), one of three pillars of the proposed MaRIE facility, will offer researchers unprecedented access to a neutron radiation environment so that the effects of radiation damage on materials can be measured in-situ, during irradiation. The calculated radiation damage conditions within the F{sup 3} match, in many respects, that of a fusion reactor first wall, making it well suited for testing fusion materials. Here we report in particular on two important characteristics of the radiation environment with relevancy to radiation damage: the primary knock-on atom spectrum and the impact of the pulse structure of the proton beam on temporal characteristics of the atomic displacement rate. With respect to both of these, analyses show the F{sup 3} has conditions that are consistent with those of a steady-state fusion reactor first wall.

Pitcher, Eric J [Los Alamos National Laboratory

2010-10-06

383

Environmental Development Plan: Magnetic Fusion.  

National Technical Information Service (NTIS)

This Environmental Development Plan (EDP) identifies the planning and management requirements and schedules needed to evaluate and assess the environmental, health and safety (EH and S) aspects of the Magnetic Fusion Energy Program (MFE). Environment is d...

1979-01-01

384

Fusion power and the environment.  

PubMed

Fusion reactor design concepts are being pursued in the research and development programme of various countries and studies are being undertaken on the possible environmental impact of fusion power reactors. The paper reviews and summarizes the results of such environmental impact studies. Attention is restricted to deuterium-tritium fusion reactor concepts and a preliminary environmental impact assessment is presented. The possible inventory tritium and radioactive materials in the neutron-activated blanket structure of fusion power reactors is described and potential hazards posed by this radioactive materials inventory are discussed. Non-radiological implications and accident considerations are outlined. In conclusion, various areas still awaiting further investigation and research work are identified. The paper contains 8 tables and 50 references. PMID:1212270

Flakus, F N

1975-09-01

385

U. S. Fusion Energy Future  

SciTech Connect

Fusion implementation scenarios for the US have been developed. The dependence of these scenarios on both the fusion development and implementation paths has been assessed. A range of implementation paths has been studied. The deployment of CANDU fission reactors in Canada and the deployment of fission reactors in France have been assessed as possible models for US fusion deployment. The waste production and resource (including tritium) needs have been assessed. The conclusion that can be drawn from these studies is that it is challenging to make a significant impact on energy production during this century. However, the rapid deployment of fission reactors in Canada and France support fusion implementation scenarios for the US with significant power production during this century. If the country can meet the schedule requirements then the resource needs and waste production are found to be manageable problems.

John A. Schmidt; Dan Jassby; Scott Larson; Maria Pueyo; Paul H. Rutherford

2000-10-12

386

Pulsed Power Driven Fusion Energy  

SciTech Connect

Pulsed power is a robust and inexpensive technology for obtaining high powers. Considerable progress has been made on developing light ion beams as a means of transporting this power to inertial fusion capsules. However, further progress is hampered by the lack of an adequate ion source. Alternatively, z-pinches can efficiently convert pulsed power into thermal radiation, which can be used to drive an inertial fusion capsule. However, a z-pinch driven fusion explosion will destroy a portion of the transmission line that delivers the electrical power to the z-pinch. They investigate several options for providing standoff for z-pinch driven fusion. Recyclable Transmission Lines (RTLs) appear to be the most promising approach.

SLUTZ,STEPHEN A.

1999-11-22

387

Z-Pinch Fusion Propulsion.  

National Technical Information Service (NTIS)

Fusion-based nuclear propulsion has the potential to enable fast interplanetary transportation. Shorter trips are better for humans in the harmful radiation environment of deep space. Nuclear propulsion and power plants can enable high Ispand payload mass...

J. Miernik

2011-01-01

388

Polarization: A Must for Fusion  

NASA Astrophysics Data System (ADS)

Recent realistic simulations confirm that the polarization of the fuel would improve significantly the DT fusion efficiency. We have proposed an experiment to test the persistence of the polarization in a fusion process, using a terawatt laser hitting a polarized HD target. The polarized deuterons heated in the plasma induced by the laser can fuse producing a 3He and a neutron in the final state. The angular distribution of the neutrons and the change in the corresponding total cross section are related to the polarization persistence. The experimental polarization of DT fuel is a technological challenge. Possible paths for Magnetic Confinement Fusion (MCF) and for Inertial Confinement Fusion (ICF) are reviewed. For MCF, polarized gas can be used. For ICF, cryogenic targets are required. We consider both, the polarization of gas and the polarization of solid DT, emphasizing the Dynamic Nuclear polarization (DNP) of HD and DT molecules.

Didelez, J. P.; Deutsch, C.; Guidal, M.

2012-10-01

389

Overview of fusion reactor safety  

SciTech Connect

Use of deuterium-tritium burning fusion reactors requires examination of several major safety and environmental issues: (1) tritium inventory control, (2) neutron activation of structural materials, fluid streams and reactor hall environment, (3) release of radioactivity from energy sources including lithium spill reactions, superconducting magnet stored energy release, and plasma disruptions, (4) high magnetic and electromagnetic fields associated with fusion reactor superconducting magnets and radio frequency heating devices, and (5) handling and disposal of radioactive waste. Early recognition of potential safety problems with fusion reactors provides the opportunity for improvement in design and materials to eliminate or greatly reduce these problems. With an early start in this endeavor, fusion should be among the lower risk technologies for generation of commercial electrical power.

Cohen, S.; Crocker, J.G.

1981-01-01

390

Condensed hydrogen for thermonuclear fusion  

NASA Astrophysics Data System (ADS)

Inertial confinement fusion (ICF) power, in either pure fusion or fission-fusion hybrid reactors, is a possible solution for future world's energy demands. Formation of uniform layers of a condensed hydrogen fuel in ICF targets has been a long standing materials physics challenge. Here, we review the progress in this field. After a brief discussion of the major ICF target designs and the basic properties of condensed hydrogens, we review both liquid and solid layering methods, physical mechanisms causing layer nonuniformity, growth of hydrogen single crystals, attempts to prepare amorphous and nanostructured hydrogens, and mechanical deformation behavior. Emphasis is given to current challenges defining future research areas in the field of condensed hydrogens for fusion energy applications.

Kucheyev, S. O.; Hamza, A. V.

2010-11-01

391

Condensed hydrogen for thermonuclear fusion  

SciTech Connect

Inertial confinement fusion (ICF) power, in either pure fusion or fission-fusion hybrid reactors, is a possible solution for future world's energy demands. Formation of uniform layers of a condensed hydrogen fuel in ICF targets has been a long standing materials physics challenge. Here, we review the progress in this field. After a brief discussion of the major ICF target designs and the basic properties of condensed hydrogens, we review both liquid and solid layering methods, physical mechanisms causing layer nonuniformity, growth of hydrogen single crystals, attempts to prepare amorphous and nanostructured hydrogens, and mechanical deformation behavior. Emphasis is given to current challenges defining future research areas in the field of condensed hydrogens for fusion energy applications.

Kucheyev, S. O.; Hamza, A. V. [Nanoscale Synthesis and Characterization Laboratory, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2010-11-15

392

Data Fusion With Communication Applications.  

National Technical Information Service (NTIS)

Data fusion ideas were employed to solve some important communication system problems. The first topic involves studying methods for generating and combining decisions from individual receivers in a multiple user scenario. The resulting theory of distribu...

R. S. Blum

2003-01-01

393

Magnetic Confinement Fusion Energy Research.  

National Technical Information Service (NTIS)

Controlled Thermonuclear Fusion offers probably the only relatively clean energy solution with completely inexhaustible fuel and unlimited power capacity. The scientific and technological problem consists in magnetically confining a hot, dense plasma (pre...

H. Grad

1977-01-01

394

Overview of fusion reactor safety  

NASA Astrophysics Data System (ADS)

Use of deuterium-tritium fusion reactors requires examination of several major safety and environmental issues: (1) tritium inventory control; (2) neutron activation of structural materials, fluid streams and reactor hall environment; (3) release of radioactivity from energy sources including lithium spill reactions, superconducting magnet stored energy release, and plasma disruptions; (4) high magnetic and electromagnetic fields associated with fusion reactor superconducting magnets and radio frequency heating devices; and (5) handling and disposal of radioactive waste. Early recognition of potential safety problems with fusion reactors provides the opportunity for improvement in design and materials to eliminate or greatly reduce these problems. With an early start in this endeavor, fusion should be among the lower risk technologies for generation of commercial electrical power.

Cohen, S.; Crocker, J. G.

395

Osmotic control of bilayer fusion.  

PubMed Central

We have used photography and capacitance measurement to monitor the steps in the interaction and eventual fusion of optically black lipid bilayers (BLMs), hydrostatically bulged to approximately hemispherical shape and pushed together mechanically. A necessary first step is drainage of aqueous solution from between the bilayers to allow close contact of the bilayers. The drainage can be controlled by varying the osmotic difference across the bilayers. If the differences are such as to remove water from between the bilayers, fusion occurs after a time that depends on the net osmotic difference and the area of contact. If there is an osmotic flow of water into the space between the bilayers, fusion never occurs. In the fusion process, a single central bilayer forms from the original apposed pair of bilayers. The central bilayer may later burst to allow mixing of the two volumes originally bounded by the separate bilayer; the topological equivalent of exocytosis. Images FIGURE 2

Fisher, L R; Parker, N S

1984-01-01

396

Splenogonadal fusion and sex reversal.  

PubMed

Splenogonadal fusion is a rare congenital malformation where an abnormal union occurs between the spleen and gonad or mesonephric derivatives. Although it occurs in females it is much less prevalent than in males (male:female ratio, 16:1), but this may partly be because of the inaccessibility of the female gonads leading to under-diagnosis. To our knowledge this is the first case of splenogonadal fusion associated with sex reversal reported in the literature. PMID:22876552

Speare, Ruth; Roberts, Julian; Cohen, Marta; Wales, Jerry

2012-01-01

397

Data fusion with minimal communication  

Microsoft Academic Search

Two sensors obtain data vectors x and y, respectively, and transmit real vectors m&oarr;1(x) and m&oarr;2(y), respectively, to a fusion center. The authors obtain tight lower bounds on the number of messages (the sum of the dimensions of m&oarr;1 and m&oarr;2) that have to be transmitted for the fusion center to be able to evaluate a given function f&oarr;(x,y). When

Zhi-quan Luo; John N. Tsitsiklis

1994-01-01

398

Prospects for Tokamak Fusion Reactors  

SciTech Connect

This paper first reviews briefly the status and plans for research in magnetic fusion energy and discusses the prospects for the tokamak magnetic configuration to be the basis for a fusion power plant. Good progress has been made in achieving fusion reactor-level, deuterium-tritium (D-T) plasmas with the production of significant fusion power in the Joint European Torus (up to 2 MW) and the Tokamak Fusion Test Reactor (up to 10 MW) tokamaks. Advances on the technologies of heating, fueling, diagnostics, and materials supported these achievements. The successes have led to the initiation of the design phases of two tokamaks, the International Thermonuclear Experimental Reactor (ITER) and the US Toroidal Physics Experiment (TPX). ITER will demonstrate the controlled ignition and extended bum of D-T plasmas with steady state as an ultimate goal. ITER will further demonstrate technologies essential to a power plant in an integrated system and perform integrated testing of the high heat flux and nuclear components required to use fusion energy for practical purposes. TPX will complement ITER by testing advanced modes of steady-state plasma operation that, coupled with the developments in ITER, will lead to an optimized demonstration power plant.

Sheffield, J.; Galambos, J.

1995-04-01

399

Cold fusion verification  

NASA Astrophysics Data System (ADS)

The objective of this work to verify and reproduce experimental observations of Cold Nuclear Fusion (CNF), as originally reported in 1989. The method was to start with the original report and add such additional information as became available to build a set of operational electrolytic CNF cells. Verification was to be achieved by first observing cells for neutron production, and for those cells that demonstrated a nuclear effect, careful calorimetric measurements were planned. The authors concluded, after laboratory experience, reading published work, talking with others in the field, and attending conferences, that CNF probably is chimera and will go the way of N-rays and polywater. The neutron detector used for these tests was a completely packaged unit built into a metal suitcase that afforded electrostatic shielding for the detectors and self-contained electronics. It was battery-powered, although it was on charge for most of the long tests. The sensor element consists of He detectors arranged in three independent layers in a solid moderating block. The count from each of the three layers as well as the sum of all the detectors were brought out and recorded separately. The neutron measurements were made with both the neutron detector and the sample tested in a cave made of thick moderating material that surrounded the two units on the sides and bottom.

North, M. H.; Mastny, G. F.; Wesley, E. J.

1991-03-01

400

Kinetic advantage of controlled intermediate nuclear fusion  

NASA Astrophysics Data System (ADS)

The dominated process of controlled fusion is to let nuclei gain enough kinetic energy to overcome Coulomb barrier. As a result, a fusion scheme can consider two factors in its design: to increase kinetic energy of nuclei and to alter the Coulomb barrier. Cold Fusion and Hot fusion are all one-factor schemes while Intermediate Fusion is a twofactors scheme. This made CINF kinetically superior. Cold Fusion reduces deuteron-deuteron distance, addressing Coulomb barrier, and Hot Fusion heat up plasma into extreme high temperature, addressing kinetic energy. Without enough kinetic energy made Cold Fusion skeptical. Extreme high temperature made Hot Fusion very difficult to engineer. Because CIFN addresses both factors, CIFN is a more promising technique to be industrialized.

Guo, Xiaoming

2012-09-01

401

Fusion Plasma Theory project summaries  

SciTech Connect

This Project Summary book is a published compilation consisting of short descriptions of each project supported by the Fusion Plasma Theory and Computing Group of the Advanced Physics and Technology Division of the Department of Energy, Office of Fusion Energy. The summaries contained in this volume were written by the individual contractors with minimal editing by the Office of Fusion Energy. Previous summaries were published in February of 1982 and December of 1987. The Plasma Theory program is responsible for the development of concepts and models that describe and predict the behavior of a magnetically confined plasma. Emphasis is given to the modelling and understanding of the processes controlling transport of energy and particles in a toroidal plasma and supporting the design of the International Thermonuclear Experimental Reactor (ITER). A tokamak transport initiative was begun in 1989 to improve understanding of how energy and particles are lost from the plasma by mechanisms that transport them across field lines. The Plasma Theory program has actively-participated in this initiative. Recently, increased attention has been given to issues of importance to the proposed Tokamak Physics Experiment (TPX). Particular attention has been paid to containment and thermalization of fast alpha particles produced in a burning fusion plasma as well as control of sawteeth, current drive, impurity control, and design of improved auxiliary heating. In addition, general models of plasma behavior are developed from physics features common to different confinement geometries. This work uses both analytical and numerical techniques. The Fusion Theory program supports research projects at US government laboratories, universities and industrial contractors. Its support of theoretical work at universities contributes to the office of Fusion Energy mission of training scientific manpower for the US Fusion Energy Program.

Not Available

1993-10-01

402

SKIDS data fusion project  

NASA Astrophysics Data System (ADS)

The European Community's strategic research initiative in information technology (ESPRIT) has been in place for nearly five years. An early example of the pan-European collaborative projects being conducted under this initiative is 'SKIDS': Signal and Knowledge Integration with Decisional Control for Multisensory Systems. This four year project, which is approaching completion, aims to build a real-time multisensor perception machine. This machine will be capable of performing data fusion, interpretation, situation assessment, and resource allocation tasks, under the constraints of both time and resource availability, and in the presence of uncertain data. Of the many possible applications, the surveillance and monitoring of a semi-automated 'factory environment' has been chosen as a challenging and representative test scenario. This paper presents an overview of the goals and objectives of the project, the makeup of the consortium, and roles of the members within it, and the main technical achievements to data. In particular, the following are discussed: relevant application domains, and the generic requirements that can be inferred from them; sensor configuration, including choice, placement, etc.; control paradigms, including the possible trade-offs between centralized, hierarchical, and decentralized approaches; the corresponding hardware architectural choices, including the need for parallel processing; and the appropriate software architecture and infra-structure required to support the chosen task oriented approach. Specific attention is paid to the functional decomposition of the system and how the requirements for control impact the organization of the identified interpretation tasks. Future work and outstanding problems are considered in some concluding remarks. By virtue of limited space, this paper is descriptive rather than explanatory.

Greenway, Phil

1992-04-01

403

Interkingdom gene fusions  

PubMed Central

Background: Genome comparisons have revealed major lateral gene transfer between the three primary kingdoms of life - Bacteria, Archaea, and Eukarya. Another important evolutionary phenomenon involves the evolutionary mobility of protein domains that form versatile multidomain architectures. We were interested in investigating the possibility of a combination of these phenomena, with an invading gene merging with a pre-existing gene in the recipient genome. Results: Complete genomes of fifteen bacteria, four archaea and one eukaryote were searched for interkingdom gene fusions (IKFs); that is, genes coding for proteins that apparently consist of domains originating from different primary kingdoms. Phylogenetic analysis supported 37 cases of IKF, each of which includes a 'native' domain and a horizontally acquired 'alien' domain. IKFs could have evolved via lateral transfer of a gene coding for the alien domain (or a larger protein containing this domain) followed by recombination with a native gene. For several IKFs, this scenario is supported by the presence of a gene coding for a second, stand-alone version of the alien domain in the recipient genome. Among the genomes investigated, the greatest number of IKFs has been detected in Mycobacterium tuberculosis, where they are almost always accompanied by a stand-alone alien domain. For most of the IKF cases detected in other genomes, the stand-alone counterpart is missing. Conclusions: The results of comparative genome analysis show that IKF formation is a real, but relatively rare, evolutionary phenomenon. We hypothesize that IKFs are formed primarily via the proposed two-stage mechanism, but other than in the Actinomycetes, in which IKF generation seems to be an active, ongoing process, most of the stand-alone intermediates have been eliminated, perhaps because of functional redundancy.

Wolf, Yuri I; Kondrashov, Alexey S; Koonin, Eugene V

2000-01-01

404

The Path to Magnetic Fusion Energy  

ScienceCinema

When the possibility of fusion as an energy source for electricity generation was realized in the 1950s, understanding of the plasma state was primitive. The fusion goal has been paced by, and has stimulated, the development of plasma physics. Our understanding of complex, nonlinear processes in plasmas is now mature. We can routinely produce and manipulate 100 million degree plasmas with remarkable finesse, and we can identify a path to commercial fusion power. The international experiment, ITER, will create a burning (self-sustained) plasma and produce 500 MW of thermal fusion power. This talk will summarize the progress in fusion research to date, and the remaining steps to fusion power.

405

The Path to Magnetic Fusion Energy  

SciTech Connect

When the possibility of fusion as an energy source for electricity generation was realized in the 1950s, understanding of the plasma state was primitive. The fusion goal has been paced by, and has stimulated, the development of plasma physics. Our understanding of complex, nonlinear processes in plasmas is now mature. We can routinely produce and manipulate 100 million degree plasmas with remarkable finesse, and we can identify a path to commercial fusion power. The international experiment, ITER, will create a burning (self-sustained) plasma and produce 500 MW of thermal fusion power. This talk will summarize the progress in fusion research to date, and the remaining steps to fusion power.

Prager, Stewart (PPPL) [PPPL

2011-05-04

406

Fusion in Magnetically Compressed Targets  

NASA Astrophysics Data System (ADS)

A comparative analysis is presented of the positive and negative features of systems using magnetic compression of the thermonuclear fusion target (MAGO/MTF) aimed at solving the controlled thermonuclear fusion (CTF) problem. The niche for the MAGO/MTF system, among the other CTF systems, in the parameter space of the energy delivered to the target, and its input time to the target, is shown. This approach was investigated at RFNC-VNIIEF for more than 15 years using the unique technique of applying explosive magnetic generators (EMG) as the energy source to preheat fusion plasma, and accelerate a liner to compress the preheated fusion plasma to the parameters required for ignition. EMG based systems produce already fusion neutrons, and their relatively low cost and record energy yield enable full scale experiments to study the possibility of achieving ignition threshold without constructing expensive stationary installations. A short review of the milestone results on the road to solving the CTF problem in the MAGO/MTF system is given.

Mokhov, V. N.

2004-11-01

407

Summary of inertial fusion sessions  

NASA Astrophysics Data System (ADS)

Laser and ion beam inertial fusion research has made remarkable progress during the last two years. As a highlight of the 22nd IAEA Fusion Energy Conference among over 30 presentations the National Ignition Facility has been reported for completion as of 27 March 2009 to achieve the first fusion shot within 2010 or 2011 with a central ignition scheme. The LFEX and OMEGA-EP fast ignition lasers have also been completed to start fast ignition feasibility studies as early as in 2009. Relativistic physics revealed many new findings on hot electron energy transport and production. For example, several proposals have been reported to control the hot electron divergence angle. Laser technology has challenged to meet the specification required for fast ignition experiments such as in the LFEX and OMEGA-EP. Target development is making steady progress to be ready for the forthcoming fast ignition integral and ion beam experiments. The LIFE engine (Laser Inertial-Confinement Fusion Fission Energy) was announced from the USA to accelerate the energy production making use of the NIF type fusion outputs in order to prepare for 'beyond the ignition' as early as 2020. KOYO-F from Osaka University, Z-machine and HiPER European projects have been reported.

Tanaka, Kazuo A.

2009-10-01

408

Fusion power for space propulsion.  

NASA Technical Reports Server (NTRS)

Principles of operation, interplanetary orbit-to-orbit mission capabilities, technical problems, and environmental safeguards are examined for thermonuclear fusion propulsion systems. Two systems examined include (1) a fusion-electric concept in which kinetic energy of charged particles from the plasma is converted into electric power (for accelerating the propellant in an electrostatic thrustor) by the van de Graaf generator principle and (2) the direct fusion rocket in which energetic plasma lost from the reactor has a suitable amount of added propellant to obtain the optimum exhaust velocity. The deuterium-tritium and the deuterium/helium-3 reactions are considered as suitable candidates, and attention is given to problems of cryogenic refrigeration systems, magnet shielding, and high-energy particle extraction and guidance.

Roth, R.; Rayle, W.; Reinmann, J.

1972-01-01

409

Laser fusion experiments at LLL  

SciTech Connect

These notes present the experimental basis and status for laser fusion as developed at LLL. Two other chapters, one authored by K.A. Brueckner and the other by C. Max, present the theoretical implosion physics and laser plasma interaction physics. The notes consist of six sections. The first is an introductory section which provides some of the history of inertial fusion and a simple explanation of the concepts involved. The second section presents an extensive discussion of diagnostic instrumentation used in the LLL Laser Fusion Program. The third section is a presentation of laser facilities and capabilities at LLL. The purpose here is to define capability, not to derive how it was obtained. The fourth and fifth sections present the experimental data on laser-plasma interaction and implosion physics. The last chapter is a short projection of the future.

Ahlstrom, H.G.

1980-06-16

410

(Meeting on fusion reactor materials)  

SciTech Connect

During his visit to the KfK, Karlsruhe, F. W. Wiffen attended the IEA 12th Working Group Meeting on Fusion Reactor Materials. Plans were made for a low-activation materials workshop at Culham, UK, for April 1991, a data base workshop in Europe for June 1991, and a molecular dynamics workshop in the United States in 1991. At the 11th IEA Executive Committee on Fusion Materials, discussions centered on the recent FPAC and Colombo panel review in the United States and EC, respectively. The Committee also reviewed recent progress toward a neutron source in the United States (CWDD) and in Japan (ESNIT). A meeting with D. R. Harries (consultant to J. Darvas) yielded a useful overview of the EC technology program for fusion. Of particular interest to the US program is a strong effort on a conventional ferritic/martensitic steel for fist wall/blanket operation beyond NET/ITER.

Jones, R.H. (Pacific Northwest Lab., Richland, WA (USA)); Klueh, R.L.; Rowcliffe, A.F.; Wiffen, F.W. (Oak Ridge National Lab., TN (USA)); Loomis, B.A. (Argonne National Lab., IL (USA))

1990-11-01

411

PCA-based image fusion  

NASA Astrophysics Data System (ADS)

IMAGE FUSION is 'the combination of two or more different images to form a fused image by using a fusion algorithm'. In this paper, an algorithm is designed in which extracts the pixels from the stacked images. Principal component analysis is carried out which aims at reducing a large set of variables to a small set that still containing most of the information that was available in the large set. The technique of principal component analysis enables us to create and use a reduced set of variables, which are called principal factors. A reduced set is much easier to analyze and interpret. In this paper, fusion of images obtained from a visible camera and that from an infrared camera is been done.

Kumar, S. Senthil; Muttan, S.

2006-06-01

412

Normal myoblast fusion requires myoferlin  

PubMed Central

Summary Muscle growth occurs during embryonic development and continues in adult life as regeneration. During embryonic muscle growth and regeneration in mature muscle, singly nucleated myoblasts fuse to each other to form myotubes. In muscle growth, singly nucleated myoblasts can also fuse to existing large, syncytial myofibers as a mechanism of increasing muscle mass without increasing myofiber number. Myoblast fusion requires the alignment and fusion of two apposed lipid bilayers. The repair of muscle plasma membrane disruptions also relies on the fusion of two apposed lipid bilayers. The protein dysferlin, the product of the Limb Girdle Muscular Dystrophy type 2 locus, has been shown to be necessary for efficient, calcium-sensitive, membrane resealing. We now show that the related protein myoferlin is highly expressed in myoblasts undergoing fusion, and is expressed at the site of myoblasts fusing to myotubes. Like dysferlin, we found that myoferlin binds phospholipids in a calcium-sensitive manner that requires the first C2A domain. We generated mice with a null allele of myoferlin. Myoferlin null myoblasts undergo initial fusion events, but they form large myotubes less efficiently in vitro, consistent with a defect in a later stage of myogenesis. In vivo, myoferlin null mice have smaller muscles than controls do, and myoferlin null muscle lacks large diameter myofibers. Additionally, myoferlin null muscle does not regenerate as well as wild-type muscle does, and instead displays a dystrophic phenotype. These data support a role for myoferlin in the maturation of myotubes and the formation of large myotubes that arise from the fusion of myoblasts to multinucleate myotubes.

Doherty, Katherine R.; Cave, Andrew; Davis, Dawn Belt; Delmonte, Anthony J.; Posey, Avery; Earley, Judy U.; Hadhazy, Michele; McNally, Elizabeth M.

2014-01-01

413

[Splenogonadal fusion: a case report].  

PubMed

Splenogonadal fusion is a rare congenital abnormality. Preoperative diagnosis is difficult but can be based on scintigraphy using technetium 99m. In most cases, the splenic tissue can be dissected off the gonadal structures easily, and if there are any doubts concerning the nature of the swelling, an intraoperative frozen section can be performed to avoid an unnecessary orchidectomy. We report the case of a 4-year-old child in whom an inguinal mass indicated surgical exploration, which documented the histological diagnosis of splenogonadal fusion. PMID:19914049

Margi, M; Boumart, K; Nkhili, H; Oulahyane, R; Cherkaoui, A; Abdelhak, M; Benhmamouch, M N

2010-01-01