The Spine Journal - Articles in Press

Transplanted mesenchymal stem cells with pure fibrinous gelatin-transforming growth factor-β1 decrease rabbit intervertebral disc degeneration - Corrected Proof

2010-07-26

Abstract: Background context: Disc degeneration is a major reason for low back pain and can be caused by apoptosis. The prevention of apoptosis using mesenchymal stem cells (MSCs) may lead to new treatments for low back pain. Previous studies have reported that transplanted MSCs can proliferate and differentiate into cells expressing some of the major phenotypic qualities of nucleus pulposus cells. However, the effects of MSC transplantation on the disc height index (DHI) and apoptosis inhibition have not yet been thoroughly investigated.Purpose: The present study evaluates the effects of MSC transplantation on DHI and its potential to inhibit apoptosis.Study design/setting: Random, controlled, animal experiment study.Methods: The annulus fibrosus of 54 white New Zealand rabbits was punctured with a 21-gauge needle, and the nucleus pulposus tissue from the intervertebral discs was aspirated. The degenerative disc model was produced in each rabbit, which were then randomly divided into three groups: degenerative model group; pure fibrinous gelatin-transforming growth factor-β1 (PFG-TGF-β1) transplanted group; and MSC-PFG-TGF-β1 transplanted group. Computed radiography imaging, magnetic resonance imaging, and histological examinations were performed at Weeks 4, 8, and 12.Results: The transplanted MSCs inhibited apoptosis and slowed the rate of decrease in DHI. Magnetic resonance imaging results showed that the MSC-PFG-TGF-β1 group had less degeneration and a slower decrease in DHI compared with both the degenerative model and PFG-TGF-β1 groups. An increased quantity of nucleus pulposus and type II collagen content and a decrease in the rate of cell apoptosis were noted in the MSC-PFG-TGF-β1 group.Conclusions: Mesenchymal stem cells can slow the rate at which the DHI decreases. This effect may be because of the inhibition of apoptosis by MSCs.

Incisional hernia after anterior lumbar interbody fusion - Corrected Proof

Nam Chull Paik — 2010-07-26

Incisional hernia is a rare complication of anterior lumbar interbody fusion . This 75-year-old female patient was diagnosed with an incisional hernia 8 months after an anterior lumbar interbody fusion surgery for degenerative spondylolisthesis with spinal stenosis at L4–L5. Computed tomography scan obtained during a Valsalva maneuver can aid in the diagnosis of incisional hernia , as it did in this patient ().

The prognosis of chronic low back pain is determined by changes in pain and disability in the initial period - Corrected Proof

2010-07-09

Abstract: Background context: The recovery of patients with chronic low back pain (LBP) is slow. Furthermore, it is recently proposed that chronic LBP needs a prognostic approach to determine who will develop clinically significant back pain. Therefore, it is imperative to identify prognostic factors that are mostly seen in chronic LBP patients at an early stage. This may give clinicians tailored advice to prevent chronicity or may refer to a specific intervention.Purpose: To investigate the contribution of demographic, work, clinical, and psychosocial variables, including new prognostic variables as changes in pain intensity and disability status, on the development of chronic LBP.Study design/setting: Prospective cohort data by merging data from three randomized trials (secondary analyses).Patient sample: Workers (n=628) on sick leave because of subacute nonspecific LBP.Outcome measures: Chronic LBP for longer than 6 months (functional measure).Methods: Potential prognostic variables were demographic, work, clinical, and psychosocial characteristics (self-report measures). We also included as prognostic variables a clinically relevant change in pain intensity and disability status. For the selection of variables and prognostic models, bootstrapping techniques were used in combination with multivariable logistic regression. The explained variance and discrimination were used to evaluate the clinical performance of the models.Results: The variables most strongly related to chronic LBP were as follows: no clinically relevant change in pain intensity and in disability status in the first 3 months, a higher pain intensity score at baseline, and a higher score for kinesiophobia. This prognostic model had a bootstrap-corrected explained variance of 37% and a discriminative ability (c index) of 0.80.Conclusions: Clinical-, work-, and psychosocial-related variables contribute to the development of chronic LBP. The most promising variables are a clinically relevant decrease in pain intensity and in disability status in the first 3 months. These variables are relevant for clinicians to advise their patients with respect to preventive measures or treatment strategies.

A comparison of magnetic and radiographic imaging artifact after using three types of metal rods: stainless steel, titanium, and vitallium - Corrected Proof

2010-07-09

Abstract: Background Context: After spinal fusion surgery, postoperative management often includes imaging with either computed tomography (CT) or magnetic resonance imaging (MRI) to assess the spinal canal and nerve roots. The metallic implants used in the fusion can cause artifact that interferes with this imaging, reducing their diagnostic value. Stainless steel is known to produce large amounts of artifact, whereas titanium is known to produce significantly less. Other alloys such as vitallium are now being used in spinal implants, but their comparison to titanium and stainless steel has not been well documented in the orthopedic literature. Titanium is a desirable metal because of its light weight and lower production of artifact on imaging, although it is not as stiff as stainless steel. Vitallium is proposed as a replacement for titanium because it has stiffness similar to stainless steel, while still being as light as titanium.Purpose: The purpose of this study was to compare the amount of artifact produced on MRI and CT by three types of spinal implants: stainless steel, titanium, and vitallium.Study Design: A prospective experimental design was used to compare three types of spinal implants used in posterior spinal fusion surgery.Outcome Measures: The resulting images were evaluated by a radiologist to measure the amount of artifact (in millimeters) and by an orthopedic surgeon to assess the diagnostic quality (on a Likert scale).Methods: A porcine torso was used for repeated MRI and CT scans before and after implantation with pedicle screws and rods made of the three metals being studied.Results: Images produced after the insertion of vitallium rods and titanium screws as well as those with titanium rods and screws were found to have less artifact and a better overall diagnostic quality than those produced with stainless steel implants. Overall, there was not a difference between the amount of artifact in the spinal images with vitallium and titanium rods, with the exception of a few trials that showed small but statistically significant differences between the two metals, where titanium had slightly better images.Conclusions: If vitallium rods are used in posterior spinal surgery in place of implants made of titanium or stainless steel, any postoperative imaging of the spine using MRI or CT should have amounts of artifact that are similar to titanium and better than stainless steel.

The increase in dural sac area is maintained at 2 years after X-stop implantation for the treatment of spinal stenosis with no significant alteration in lumbar spine range of movement - Corrected Proof

2010-07-09

Abstract: Background Context: The X-stop interspinous process decompression (IPD) device has been used effectively in the management of symptomatic spinal stenosis. This study examines the radiological outcomes at 2 years postoperatively after X-stop implantation.Purpose: To measure the effect of X-stop IPD device on the dural sac and foraminal areas at 24 months postoperatively at instrumented level in symptomatic lumbar canal stenosis. We also aimed to assess its effect on change in lumbar spine movement.Study Design: Prospective observational study.Patient Sample: Forty-eight patients treated with X-stop had preoperative positional magnetic resonance imaging (MRI) scans, 40 of whom had 2 years postoperative positional MRI scans. Complete scans were available for 39 of these patients.Outcome Measures: Positional MRI scans were performed pre- and postoperatively. Measurements were done on these scans and are presented as the outcome measures.Methods: All patients had a multipositional MRI scan preoperatively and at 6 and 24 months postoperatively. Foraminal area was measured in flexion and extension. Dural cross-sectional area was measured in standing erect and in sitting neutral, flexion, and extension (sitting) positions. The total range of movement (ROM) of the lumbar spine and individual segments was also measured.Results: Complete scan data for 39 patients' scans were available. An increase in mean dural sac area was found in all positions. At 24 months after surgery, the mean dural sac area increased significantly in all four postures mentioned above. A small increase in mean foraminal area was noted, but this was not statistically significant. Mean anterior disc height reduced from 5.9 to 4.1 mm (p=.006) at 24 months at the instrumented level in single-level cases, from 7.7 to 6.1 mm (p=.032) in double-level cases caudally, and from 8.54 to 7.91 (p=.106) mm cranially. We hypothesize that the reduction in anterior disc heights could be a result of the natural progression of spinal stenosis with aging. There was no significant change in posterior disc heights at instrumented level or adjacent levels. The mean lumbar spine motion was 21.7° preoperatively and 23° at 24 months (p=.584) in single-level cases. This was 32.1° to 31.1° (p=.637) in double-level cases. There was no significant change in the individual segmental range of motion at instrumented and adjacent levels.Conclusion: X-stop interspinous device remains effective in decompressing the stenosed spinal segment by increasing the anatomic dural cross-sectional area and foraminal area of spinal canal. It does not significantly alter the ROM of lumbar spine at instrumented and adjacent levels at 24 months postoperatively.

The genetics of pain: implications for evaluation and treatment of spinal disease - Corrected Proof

David H. Kim, Carolyn E. Schwartz — 2010-07-08

Abstract: Background context: Variability in human pain experience appears to be at least partially determined by genetic inheritance. To the extent that awareness of individual pain sensitivity and the tendency to develop chronic pain after injury or surgery would be informative for clinical decision making, development and use of genetic testing for specific pain markers could contribute to improved outcomes in management of spinal disease.Purpose: To review important and illustrative results from both classical and modern pain genetics studies and to introduce readers to critical definitions and concepts necessary to interpret the growing body of genetics literature relevant to spinal disease.Study design/setting: Literature review and commentary.Methods: A review was performed of published English language studies in which genetic techniques were used to analyze the molecular basis of nociceptive signaling or processing with a particular emphasis on studies addressing genetic determinants of interindividual variability in pain sensitivity or predisposition to chronic pain.Results: There is compelling evidence indicating that interindividual differences in pain sensitivity and the risk of developing chronic pain syndromes are genetically determined. Despite a growing list of putative “pain genes,” genetic association studies remain plagued with difficulty replicating initial findings in different cohorts.Conclusions: Genome-wide association studies are potentially powerful means of identifying clinically relevant genetic markers predicting disease susceptibility, severity, and treatment response. However, accurate results require rigorous study design with use of large homogeneous populations and precise phenotypes.

The anatomic suitability of the C2 vertebra for intralaminar and pedicular fixation: a computed tomography study - Corrected Proof

2010-07-08

Abstract: Background Context: Several methods have been used to stabilize the atlantoaxial joint, including the use of C2 pedicle and laminar screws. No report has used computed tomography (CT) angiograms to compare the risk to the vertebral artery or assess the suitability for each fixation technique.Purpose: To compare the suitability of C2 pedicle versus laminar screws using CT angiograms.Study Design: We retrospectively evaluated the anatomic dimensions of the C2 lamina and pedicle in 50 patients using CT angiograms.Methods: We retrospectively reviewed the last 50 patients admitted who underwent CT angiograms of the head and neck. Data recorded included the pedicle length and width and the laminar length and width. Vertebral artery anatomy was also assessed to determine if an aberrant location would preclude pedicle fixation.Results: Mean pedicle length and width were 15.5±3.5 and 4.7±1.7 mm, respectively, with 24% of patients having anatomy that would preclude 3.5-mm pedicle screw fixation. The mean lamina length and width were 25.2±3.6 and 5.5±1.4 mm, and more than 90% of patients could tolerate a 3.5-mm C2 laminar screw.Conclusion: Preoperative CT angiography or non contrast CT is an excellent method to delineate the anatomy at C2 to determine the suitability for pedicle or intralaminar fixation. In cases where vertebral artery anatomy precludes C2 pedicle fixation, more than 90% of patients may be a candidate for C2 intralaminar fixation.

An in vitro study of dynamic cyclic compressive stress on human inner annulus fibrosus and nucleus pulposus cells - Corrected Proof

Hwan Tak Hee, Jituan Zhang, Hee Kit Wong — 2010-07-05

Abstract: Background Context: Intervertebral disc (IVD) cells exhibit diverse biologic responses to compressive stress depending on the compressive stress type, magnitude, duration, and anatomic zone of IVD cell origin. The previous studies mainly focused on the effects of compressive stress on animal IVD tissue. Few studies have investigated the response of human IVD tissue to compressive stress.Purpose: To assess the effect of dynamic cyclic compressive stress on biosynthesis of collagen and glycosaminoglycan of human inner annulus fibrosus (AF) and nucleus pulposus (NP) cells.Study Design/Setting: Observation of moderate and high magnitudes of compressive stress on human IVD cell biosynthesis.Patient Sample: Human IVD of adolescent idiopathic scoliosis case undergoing thoracoscopic discectomy and fusion was collected.Outcome Measures: Cell morphology, cell proliferation assay, as well as collagen and glycosaminoglycan content were examined in vitro.Methods: Intervertebral discs were cultured under 0.2 or 0.4 MPa of compressive stress at 1 Hz for 2 hours twice a day up to 7 days. These were compared with samples unloaded. The analysis was done via electron microscopy examination, cell proliferation assay, as well as collagen and glycosaminoglycan content analysis.Results: Collagen and glycosaminoglycan content in the inner AF and NP cells cultured under 0.2 MPa of compressive stress was significantly higher than that in the control cells but was significantly lower than that in the control cells under 0.4 MPa of compressive stress. The number of endoplasmic reticulum in the inner AF and NP cells cultured under 0.2 MPa of compressive stress was significantly higher than that in the control cells but was significantly lower than that in the control cells under 0.4 MPa of compressive stress.Conclusion: These findings imply that biosynthetic characteristics of human inner AF and NP cells may vary under varying degrees of compressive stresses, which may result in varying amounts of extracellular matrix being secreted.

Complications with recombinant human bone morphogenetic protein-2 in posterolateral spine fusion associated with a dural tear - Corrected Proof

2010-07-02

Abstract: Background Context: Potential complications related to ectopic bone formation, as seen with transforaminal lumbar interbody fusion, have always been a concern with the use of bone morphogenetic proteins (BMPs). Although less clearly anticipated, complications related to the proinflammatory effects of recombinant human bone morphogenetic protein-2 (rhBMP-2), such as swelling and edema in the cervical spine, have been observed as well. Until recently, risks related to intradural exposure to BMP have not been widely considered. However, a recent animal study reports “in the presence of a SCI and/or dural tear, rhBMP-2 diffuses intrathecally and activates a signaling cascade in all major CNS cell types, which may increase glial scarring and impact neurologic recovery.” Although this study was conducted at the spinal cord level, the observation generates obvious concerns for the much more common scenario of a dural tear associated with lumbar decompression and fusion.Purpose: The purpose of this study was to look for any indication of neurologic injury or impaired neurologic recovery in patients treated with rhBMP-2 for lumbar fusion complicated by dural tear.Study Design/Setting: Propensity score matched case-control study.Patient Sample: From consecutive series of 1,037 patients who underwent decompression and posterolateral lumbar spine fusion using rhBMP-2/absorbable collagen sponge between 2003 and 2006, intraoperative dural tear was reported in 58 cases (5.59%).Outcome Measures: Preoperative and 2-year postoperative Oswestry Disability Index, Short Form-36 (SF-36), leg pain, and back pain scores.Methods: Fifty-eight cases in which decompression and posterolateral spinal fusion were complicated by dural tear, where propensity score matched to a group without dural tear, based on age, smoking status, number of surgical levels and preoperative Oswestry Disability Index, SF-36 Physical Composite Summary score, SF-36 Mental Composite Summary (MCS) score, and back and leg pain scores. The patients with a dural tear were then compared with the matched cohort with regard to baseline and 2-year patient-based outcome measures. Particular attention was given to indices of leg pain that might reflect an influence of rhBMP-2 on neurologic function or impaired neurologic recovery.Results: No patient in the group with a dural tear and three patients in the group without a dural tear complained of new onset radiculopathy postoperatively, with one requiring oral steroids. The radiculopathy resolved within 6 months postoperatively in all three patients. Statistically significant improvement was observed in all health-related quality of life (HRQOL) measures, except SF-36 MCS, at both 1 and 2 years postoperatively in both groups. There were no significant differences in any HRQOL parameter between the groups with or without a dural tear at either 1 or 2 years postoperatively. In particular, the leg pain improvement, 2.2 points in the group with a dural tear and 2.4 points in the group without a dural tear, was statistically equivalent.Conclusions: The data suggests fairly convincingly that the presence of a repairable dural tear is not necessarily an impediment to the use of rhBMP-2 in posterolateral fusion. Further studies are needed to address the less common clinical scenario of BMP use in conjunction with spinal cord injury, as studied in the animal model that prompted this investigation. Finally, avoidance of BMP use may still be prudent in the setting of an unrepairable dural tear.

Reduction of postoperative pain after lumbar microdiscectomy with DuraSeal Xact Adhesion Barrier and Sealant System - Corrected Proof

Patrick Fransen — 2010-06-14

Abstract: Background context: An excessive amount of scar tissue after lumbar microdiscectomy may increase postoperative pain. Several fibrosis inhibitors have been used in the past in an endeavor for better functional outcome.Purpose: The goal of this study was to evaluate DuraSeal XactTM Adhesion Barrier and Sealant System (DSX), a polyethylene glycol-based synthetic fibrosis inhibitor, for its ability to reduce postoperative pain after lumbar microdiscectomy.Study design: This is a prospective randomized controlled study.Patient sample: Twenty patients between 19 and 71 years of age about to undergo elective lumbar single-level discectomy were randomized into two groups of 10.Outcome measures: Assessments included the visual analog scale (VAS) pain score, the short form (SF)-36 questionnaire, and the Oswestry low back pain scale, preoperatively and at discharge, and 30, 90, and 180 days after surgery.Methods: One group was treated with DSX, and the control group received the local standard of care. DSX was applied as a thin layer on the nerve root and surrounding area after microdiscectomy.Results: The VAS pain scale was lower at all time points in the DSX treatment group than in the control group. The reductions at 30, 90, and 180 days for DSX and control groups, respectively, were 43.9% versus 35.6%, 64.3% versus 44.8%, and 75.4% versus 59.6%. The SF-36 scores in the DSX treatment group showed more improvement than in the control group as soon as 30 days for physical functioning, general health, vitality, social functioning, mental health, and emotional patterns, and by 90 days for bodily pain and general health. The Oswestry pain score was lower at all time points in the DSX treatment group than in the control group. The reductions at 30, 90, and 180 days for DSX and control groups, respectively, were 41.5% versus 34.3%, 68.2% versus 42.4%, and 73.3% versus 55.4%. Wound healing was normal in the DSX treatment group, there were no complications related to DSX use, and no patient in either group required reoperation.Conclusions: Although this study is too small to have conclusions of efficacy and will need confirmation by larger trials, treatment of a microdiscectomy site with DSX for fibrosis prevention shows promising results in terms of safety, reduction of postoperative pain and functional results when compared to control with the additional advantage of being suitable for use in the presence of a dural tear.

Characterization of combat-related spinal injuries sustained by a US Army Brigade Combat Team during Operation Iraqi Freedom - Corrected Proof

Andrew J. Schoenfeld, Gens P. Goodman, Philip J. Belmont — 2010-06-14

Abstract: Background Context: The United States is presently engaged in the largest scale armed conflict since Vietnam. Despite recent investigations into the scope of injuries sustained by soldiers in Iraq and Afghanistan, little information is available regarding the incidence and epidemiology of spine trauma in this population.Purpose: Characterize the incidence and epidemiology of spinal injuries sustained during combat by soldiers of a US Army Brigade Combat Team (BCT) that participated in Operation Iraqi Freedom.Study Design: Descriptive epidemiologic study.Patient Sample: A total of 4,122 soldiers who served in Iraq with an Army BCT during “The Surge” operation.Outcome Measures: Spine injury epidemiology was calculated for the BCT, including the spine combat casualty rate, and percent medically evacuated (MEDEVAC).Methods: Unit rosters were obtained, and a comprehensive database identifying all combat-related spine injuries was created by querying each soldiers' electronic medical record and the unit's casualty rosters. Demographic information was recorded including age, sex, rank, injury mechanism, presence of polytrauma, and injury outcome. Injury outcomes were classified as killed in action, died of wounds, MEDEVAC, or returned to duty. The incidence of spine injuries was determined, and epidemiology was characterized using calculations of the spine combat casualty rate and percent MEDEVAC. Comparisons were made to published reports from previous conflicts.Results: A total of 29 soldiers sustained 31 combat-related spine injuries. These accounted for 7.4% (29 out of 390) of all casualties sustained during combat. Blunt trauma to the spine, often resulting from an explosive mechanism, was encountered in 65% of cases. Closed fractures of the spine occurred in 21% of casualties and open injuries occurred in 7%. The spine combat casualty rate was 5.6 out of 1,000 soldier combat-years, and the percent MEDEVAC was 19%.Conclusions: This investigation is the first of its kind, documenting the nature of spine trauma in a major American conflict. The incidence of spine injuries in this study is the highest ever documented and is indicative of the tactics used by the enemy in the current war. Given this fact, it is likely that the prevalence of combat-related spine trauma will increase in the future. Larger, more extensive, studies of this kind must be conducted in the future.

Back disorders among Israeli youth: a prevalence study in young military recruits - Corrected Proof

2010-06-11

Abstract: BACKGROUND CONTEXT: Back problems are reported with increasing frequency in adults and adolescents. Most information is from self-reported questionnaires or studies with small sample sizes. Reports were usually focused on specific diseases and biased toward overdiagnosis.PURPOSE: To assess the prevalence of common back disorders among a large cohort of 17-year-old males and females recruited by the Israel Defense Forces (IDF).STUDY DESIGN: A retrospective cross-sectional prevalence study.PATIENT SAMPLE: Seventeen-year-old Israeli male and female military recruits reporting as directed by the IDF for preinduction medical examination between January 01, 1998 and December 31, 2006.OUTCOME MEASURES: Military functional limitation Grades 1 to 7 per diagnosis category.METHODS: Military recruits were examined and classified based on medical and orthopedic diagnoses. They were referred for orthopedic consultation as necessary. Four orthopedic classifications were used: spinal deformity (including kyphosis and scoliosis), back pain (including neck and radicular syndromes), spondylolysis/olisthesis, and limitations resulting from trauma or spinal surgery. Data were coded into a central database, and descriptive statistics are presented.RESULTS: The overall prevalence of back disorders among 828,171 17-year-old military recruits (61.5% male) was 16.8%. Back disorders resulting in significant functional limitation were diagnosed in 0.8% of recruits. The most prevalent diagnoses were spinal deformities (kyphosis and scoliosis, females 11.9%, males 11.5%) and back pain (females 3.0%, males 5.6%). Most of these diagnoses were rated as mild.CONCLUSIONS: When using objective criteria, overall back disorders in a large population of 17-year-old recruits were 17%, considerably lower than most reports. Back morbidity severe enough to prevent combat duty occurred at a rate of less than 1%, suggesting that serious back morbidity is not a frequent finding in this age group.LEVEL OF EVIDENCE: Symptom prevalence study, Level III.

Preclinical evaluation of the Dynesys posterior spinal stabilization system: a nonhuman primate model - Corrected Proof

2010-05-24

Abstract: Background Context: Posterior dynamic spinal stabilization systems are intended to restore near-normal biomechanical function of the spine without inducing unnatural stresses to the spinal elements or eliciting a histopathological response. These devices must resist loosening within the challenging biomechanical environment of the lumbar spine.Purpose: To determine the biomechanical effects of the Dynesys dynamic stabilization system (Zimmer, Inc., Warsaw, IN, USA) in the acute postoperative period and after 6 and 12 months in vivo; to examine the facet joints at the same postoperative intervals for signs of degeneration; and to measure the incidence of screw loosening after in vivo loading.Study Design/Setting: This was an in vitro and in vivo animal survival study.Methods: Fourteen baboons were used. Eight animals underwent survival surgery to implant a posterior dynamic stabilization system spanning two lumbar levels. Six animals were sacrificed acutely, and their spines were biomechanically tested in the intact condition and with instrumentation implanted as described above. Six animals in the survival group were sacrificed at 6 months postoperatively and two animals at 12 months postoperatively. Their spines were biomechanically tested with instrumentation in situ and explanted. The facets were then processed using undecalcified technique. Microradiographs of the facets were examined for signs of arthrosis, inflammation, and degenerative changes.Results: The range of flexion-extension motion for the acute group of instrumented spines was 27% of the intact condition. After 6 months with instrumentation in situ, flexion-extension was 56% of the intact condition. After 12 months with instrumentation in situ, flexion-extension was 70% of the intact condition. With instrumentation explanted, flexion-extension at 6 and 12 months was not different from the intact condition (p>.05). Similar results were observed for lateral bending. There were no significant differences in axial rotation between any groups at any time point (p>.05). The facet joints at the operative and adjacent levels exhibited normal articular cartilage at both the 6- and 12-month postoperative time points. There was no evidence of facet arthrosis in any animal. At 6 months postoperatively, 0 of 36 screws exhibited radiolucency at the bone-metal interface. At 12 months postoperatively, 3 of 12 screws exhibited radiolucency.Conclusions: After 12 months in vivo, spinal motions were stabilized by the dynamic instrumentation system. No facet arthrosis was observed at 6 and 12 months postoperatively. Explantation of the instrumentation restored motion to intact levels. A 25% rate of screw loosening (3 of 12 screws) was observed at the 12-month postoperative time point.

Recurrent back and leg pain and cyst reformation after surgical resection of spinal synovial cysts: systematic review of reported postoperative outcomes - Corrected Proof

2010-05-21

Abstract: Background Context: With improvements in neurological imaging, there are increasing reports of symptomatic spinal synovial cysts. Surgical excision has been recognized as the definitive treatment for symptomatic juxtafacet cysts. However, the role for concomitant fusion and the incidence of recurrent back pain and recurrent cyst formation after surgery remain unclear.Purpose: To determine the cumulative incidence of postoperative symptomatic relief, recurrent back and leg pain after cyst resection and decompression, and synovial cyst recurrence.Study Design: Systematic review of the literature.Patient Sample: All published studies to date reporting outcomes of synovial cyst excision with and without spinal fusion.Outcome Measures: Cyst recurrence and Kawabata, Macnab, Prolo, or Stauffer pain scales.Methods: We performed a systematic literature review of all articles published between 1970 and 2009 reporting outcomes after surgical management of spinal synovial cysts.Results: Eighty-two published studies encompassing 966 patients were identified and reviewed. Six hundred seventy-two (69.6%) patients presented with radicular pain and 467 (48.3%) with back pain. The most commonly involved spinal level was L4–L5 (75.4%), with only 25 (2.6%) and 12 (1.2%) reported synovial cysts in the cervical or thoracic area, respectively. Eight hundred eleven (84.0%) patients were treated with decompressive surgical excision alone, whereas 155 (16.0%) received additional concomitant spinal fusion. Six hundred fifty-four (92.5%) and 880 (91.1%) patients experienced complete resolution of their back or leg pain after surgery, respectively. By a mean follow-up of 25.4 months, back and leg pain recurred in 155 (21.9%) and 123 (12.7%) patients, respectively. Sixty (6.2%) patients required reoperation, of which the majority (n=47) required fusion for correction of spinal instability and mechanical back pain. Same-level synovial cyst recurrence occurred in 17 (1.8%) patients after decompression alone but has been reported in no (0%) patients after decompression and fusion.Conclusions: Surgical decompression results in symptomatic resolution in the vast majority of patients; however, recurrent back pain occurs in a significant number of patients. Cyst recurrence occurs in less than 2% of patients but has never been reported after cyst excision with concomitant fusion. The lack of cyst recurrence after concomitant fusion supports the need to investigate the value of fusion of the involved motion segment in the treatment of symptomatic synovial cysts of the spine.

The difference in spine specimen dual-energy X-ray absorptiometry bone mineral density between in situ and in vitro scans - Corrected Proof

Juay Seng Tan, Mark M. Kayanja, Selvon F. St. Clair — 2010-04-12

Abstract: Background Context: Human cadaveric specimens are commonly used to evaluate bone-implant interface strength in osteoporotic spine fixation. Dual-energy X-ray absorptiometry (DXA) scans are usually carried out on explanted spine specimens to measure bone mineral density (BMD) before in vitro biomechanical studies are carried out.Purpose: The purposes of this study were to verify and quantify the difference in DXA BMD between unexplanted (in situ) and explanted (in vitro) scans and to develop and validate a correction factor (CF) between in vitro and in situ DXA BMD.Study Design: This is a retrospective analysis of past DXA scans of explanted specimens and a repeated measure scan rescan study of in situ and in vitro spine specimens.Methods: Dual-energy X-ray absorptiometry scans were previously carried out on 106 male and 83 female lumbar specimens. Using multiple regressions, the correlation functions between Z score, BMD, and age were determined for male and female groups. The CF was developed based on difference in BMD between mean in vitro and population data. Next, in situ DXA scans were carried out on the lumbar spine of four full human cadavers, and subsequently, in vitro scans were repeated after explantation. The CF was applied to these in vitro scan data and the resulting corrected BMD compared with in situ scan values.Results: The specimens had significantly lower Z score than population mean. The mean Z score was −0.7±1.4 (p<.001) for male and −0.3±1.3 (p=.03) for female specimens. The difference between in situ and in vitro scans was quantified to be 0.06 g/cm2 for male specimens and to be a function of age (6.80 Age−0.5−3.76 Age−0.365) for female specimens. In vitro BMD was 96±11% of in situ BMD and was significantly different (p=.04). Corrected BMD after application of CF was 97±11% of in situ BMD and was not significantly different (p=.13).Conclusions: In vitro BMD scan on explanted specimens measured lower DXA values than in situ BMD scans on full cadavers. A CF when used resulted in more accurate measure of the in situ BMD.

Reliability assessment of Cobb angle measurements using manual and digital methods - Corrected Proof

Michelle C. Tanure, Alan P. Pinheiro, Anamaria S. Oliveira — 2010-04-02

Abstract: Background Context: The vertebral spine angle in the frontal plane is an important parameter in the assessment of scoliosis and may be obtained from panoramic X-ray images. Technological advances have allowed for an increased use of digital X-ray images in clinical practice.Purpose: In this context, the objective of this study is to assess the reliability of computer-assisted Cobb angle measurements taken from digital X-ray images.Study Design/Setting: Clinical investigation quantifying scoliotic deformity with Cobb method to evaluate the intra- and interobserver variability using manual and digital techniques.Patient Sample: Forty-nine patients diagnosed with idiopathic scoliosis were chosen based on convenience, without predilection for gender, age, type, location, or magnitude of the curvature.Outcome Measures: Images were examined to evaluate Cobb angle variability, end plate selection, as well as intra- and interobserver errors.Methods: Specific software was developed to digitally reproduce the Cobb method and calculate semiautomatically the degree of scoliotic deformity. During the study, three observers estimated the Cobb angle using both the digital and the traditional manual methods.Results: The results showed that Cobb angle measurements may be reproduced in the computer as reliably as with the traditional manual method, in similar conditions to those found in clinical practice.Conclusions: The computer-assisted method (digital method) is clinically advantageous and appropriate to assess the scoliotic curvature in the frontal plane using Cobb method.

Biomimetic calcium phosphate coatings as bone morphogenetic protein delivery systems in spinal fusion - Corrected Proof

2010-01-25

Abstract: Background Context: Use of recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to enhance spinal fusion rates. Case reports of soft-tissue swelling, ectopic bone formation, and osteolysis have recently surfaced. It is hypothesized that incorporation of rhBMP-2 within a calcium phosphate (CaP) coating may help to localize delivery and mitigate these complications.Purpose: To compare the characteristics of posterolateral fusion between rabbits receiving rhBMP-2 delivered via physical adsorption to a collagen sponge or rhBMP-2 incorporated within the physical structure of a CaP coating on a collagen sponge.Study Design/Setting: New Zealand white rabbit model of posterolateral lumbar fusion at L5–L6.Methods: Eighteen (18) New Zealand white rabbits underwent posterolateral spinal fusion at L5–L6. Rabbits received bilateral collagen sponges that were either coated with CaP (n=3), coated with CaP and dipped in rhBMP-2 (n=3), coated with a hybrid CaP–rhBMP-2 film (n=6), or coated with a hybrid CaP-rhBMP-2 film and dipped in rhBMP-2 (n=6). Animals were followed weekly with radiographs and were sacrificed at 6 weeks. Fusion masses were further characterized by manual palpation, computed tomography, and histology.Results: Radiographic evaluation showed that animals in Group 3 (incorporated BMP) fused at 4 weeks, whereas animals in Group 2 (adsorbed BMP) and Group 4 (incorporated and adsorbed BMP) fused by 6 weeks. Animals that received rhBMP-2 physically adsorbed to the collagen sponge showed extension of the fusion mass beyond the L5–L6 level in 56% of cases and bone resorption in 78%. Histology of fusion masses showed mature bone formation in animals belonging to Groups 2, 3, and 4 and extensive osteoclast recruitment in animals belonging to Groups 2 and 4.Conclusions: Delivery of rhBMP-2 via incorporation within CaP coatings results in increased rates of radiographic fusion. The burst release profile of rhBMP-2 adsorbed to surfaces, although effective in achieving fusion, may result in increased osteoclast recruitment.

SWISSspine—a nationwide health technology assessment registry for balloon kyphoplasty: methodology and first results - Corrected Proof

2009-10-12

Abstract: Background Context: The Swiss Federal Office of Public Health demanded a nationwide health technology assessment registry for cervical and lumbar total disc arthroplasty and for balloon kyphoplasty (BKP) to make a decision about reimbursement of these interventions.Purpose: The goal of the SWISSspine registry is to generate evidence about the safety and effectiveness of these technologies. We report on results of patients with balloon kyphoplasty.Study Design/Setting: Prospective, multicenter, observational case series.Patient Sample: From March 2005 until June 2008, 331 interventions with 391 treated levels in 320 patients have been documented. 75.6% of patients were females with mean age of 74 years (range 43–95.2 years); mean age of males was 72.6 years (range 41.4–93 years).Outcome Measures: Surgeon-administered outcome instruments were primary intervention form for BKP, implant, and follow-up form; patient self-reported measures were Euroqol-5D, North American Spine Society, and a comorbidity questionnaire.Methods: Data were recorded perioperative, at 3 months, 1 year, and annually thereafter. Wilcoxon signed-rank test was used for comparison of preoperative to postoperative measurements. Multivariate regression was used for identifying factors with a significant influence on the outcome.Results: Significant and clinically relevant reduction of back pain, improvement of quality of life (QoL), and reduction of pain killer consumption were seen in the 1-year follow-up. Improvement of preoperative segmental kyphosis was achieved in the majority of cases. There were three symptomatic cement extrusions with radiculopathy documented.Conclusions: Balloon kyphoplasty is a safe and effective treatment concerning pain reduction, QoL improvement, and pain killer consumption. The SWISSspine registry proved to be an excellent tool for evaluation of this new technology, and its results, in combination with an elaborate health technology assessment report, led to a permanent coverage of BKP by the basic health insurance.

REMOVED: In defense of King et al.: the validity of manual examination in assessing patients with neck pain - Corrected Proof

Nikolai Bogduk — 2008-11-10

This article has been removed consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The Publisher apologizes for any inconvenience this may cause.

Evaluation of five scoring systems for cervical spondylogenic myelopathy - Corrected Proof

Kristina Dalitz, Hans-Ekkehart Vitzthum — 2008-09-09

Abstract: Background context: Comparison of measured clinical deficits and outcomes is vital for international discussion about the identification and treatment of cervical spondylotic myelopathy (CSM). There is currently little information comparing outcomes as assessed by different CSM scoring systems.Purpose: To qualitatively and quantitatively analyze five specific CSM outcome scores that are frequently used to assess the grade of severity and outcome after operative decompression.Study design: This retrospective study evaluated the Nurick score, the Japanese Orthopedic Association score (JOA score), the Cooper myelopathy scale (CMS), the Prolo score, and the European myelopathy score (EMS).Patient sample: The study included 43 patients with clinical and morphological signs of CSM, who underwent ventral decompression. Data were evaluated in sufficient detail to objectively assess the scores.Outcome measures: Clinical findings (funicular and radicular symptoms), recovery rate, symptom duration, age, economic situation, time away from employment, somatic-evoked potentials, and radiological findings were assessed.Methods: Scores were assessed using both pre- and postoperative clinical data. Correlations between scores, score improvement, and how well the scores reflected the clinical, diagnostic, and anamnestic data were analyzed using nonparametric, descriptive statistical tests. The recovery rate, as a measure of cumulative outcome, was also assessed and compared for each scoring system.Results: All five scores were suitable for qualitatively assessing the clinical characteristics and progression of cervical myelopathy. All showed a statistically significant correlation (p<.05), and measured postoperative improvement (p<.001). All scores also reflected clinical deficits except for the Prolo score, which rates the severity of CSM with an emphasis on data related to the economic impact on the patient's situation rather than on clinical symptoms per se. Quantitative assessment of clinical symptom improvement varied greatly among the scores, for example, Nurick score (33%) versus JOA score (81%). The recovery rates, as a measure of cumulative improvement, showed less variation among most of the scores. The Nurick score and the EMS measured clinical deficit improvements in significantly fewer patients than did the JOA score (p<.05).Conclusions: Evaluating the recovery rate is essential for comparing the results of the five CSM scores evaluated in this study. There was a large quantitative difference among the scores as the result of the different criteria used to produce each score. Qualitatively, all five scores allowed evaluation of cervical myelopathy, but only the recovery rate allowed for statistical comparison. Advancements in the treatment of CSM depend on the ability of clinicians to evaluate the therapeutic results of CSM studies. This study suggests that using the recovery rate to assess outcome is best for comparing studies that use different scores.