Showing papers in "Spine in 2013"

Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis.

Abstract: Study design Prospective multicenter study evaluating operative (OP) versus nonoperative (NONOP) treatment for adult spinal deformity (ASD). Objective Evaluate correlations between spinopelvic parameters and health-related quality of life (HRQOL) scores in patients with ASD. Summary of background data Sagittal spinal deformity is commonly defined by an increased sagittal vertical axis (SVA); however, SVA alone may underestimate the severity of the deformity. Spinopelvic parameters provide a more complete assessment of the sagittal plane but only limited data are available that correlate spinopelvic parameters with disability. METHODS.: Baseline demographic, radiographical, and HRQOL data were obtained for all patients enrolled in a multicenter consecutive database. Inclusion criteria were: age more than 18 years and radiographical diagnosis of ASD. Radiographical evaluation was conducted on the frontal and lateral planes and HRQOL questionnaires (Oswestry Disability Index [ODI], Scoliosis Research Society-22r and Short Form [SF]-12) were completed. Radiographical parameters demonstrating highest correlation with HRQOL values were evaluated to determine thresholds predictive of ODI more than 40. Results Four hundred ninety-two consecutive patients with ASD (mean age, 51.9 yr) were enrolled. Patients from the OP group (n = 178) were older (55 vs. 50.1 yr, P Conclusion ASD is a disabling condition. Prospective analysis of consecutively enrolled patients with ASD demonstrated that PT and PI-LL combined with SVA can predict patient disability and provide a guide for patient assessment for appropriate therapeutic decision making. Threshold values for severe disability (ODI > 40) included: PT 22° or more, SVA 47 mm or more, and PI - LL 11° or more.

AOSpine thoracolumbar spine injury classification system: fracture description, neurological status, and key modifiers.

Abstract: STUDY DESIGN Reliability and agreement study, retrospective case series. OBJECTIVE To develop a widely accepted, comprehensive yet simple classification system with clinically acceptable intra- and interobserver reliability for use in both clinical practice and research. SUMMARY OF BACKGROUND DATA Although the Magerl classification and thoracolumbar injury classification system (TLICS) are both well-known schemes to describe thoracolumbar (TL) fractures, no TL injury classification system has achieved universal international adoption. This lack of consensus limits communication between clinicians and researchers complicating the study of these injuries and the development of treatment algorithms. METHODS A simple and reproducible classification system of TL injuries was developed using a structured international consensus process. This classification system consists of a morphologic classification of the fracture, a grading system for the neurological status, and description of relevant patient-specific modifiers. Forty cases with a broad range of injuries were classified independently twice by group members 1 month apart and analyzed for classification reliability using the Kappa coefficient (κ). RESULTS The morphologic classification is based on 3 main injury patterns: type A (compression), type B (tension band disruption), and type C (displacement/translation) injuries. Reliability in the identification of a morphologic injury type was substantial (κ= 0.72). CONCLUSION The AOSpine TL injury classification system is clinically relevant according to the consensus agreement of our international team of spine trauma experts. Final evaluation data showed reasonable reliability and accuracy, but further clinical validation of the proposed system requires prospective observational data collection documenting use of the classification system, therapeutic decision making, and clinical follow-up evaluation by a large number of surgeons from different countries.

Cervical radiographical alignment: comprehensive assessment techniques and potential importance in cervical myelopathy.

Abstract: Study design Narrative review. Objective To provide a comprehensive narrative review of cervical alignment parameters, the methods for quantifying cervical alignment, normal cervical alignment values, and how alignment is associated with cervical deformity and myelopathy with discussions of health-related quality of life. Summary of background data Indications for surgery to correct cervical alignment are not well-defined and there is no set standard to address the amount of correction to be achieved. In addition, classifications of cervical deformity have yet to be fully established and treatment options defined and clarified. Methods A survey of the cervical spine literature was conducted. Results New normative cervical alignment values from an asymptomatic volunteer population are introduced, updated methods for quantifying cervical alignment are discussed, and describing the relationship between cervical alignment, disability, and myelopathy are outlined. Specifically, methods used to quantify cervical alignment include cervical lordosis, cervical sagittal vertical axis, and horizontal gaze with the chin-brow vertical angle. Updated methods include T1 slope. Evidence from a few recent studies suggests correlations between radiographical parameters in the cervical spine and health-related quality of life. Analysis of the cervical regional alignment with respect to overall spinal pelvic alignment is emerging and critical. Cervical myelopathy and sagittal alignment of the cervical spine are closely related as cervical deformity can lead to spinal cord compression and tension. Conclusion Cervical deformity correction should take on a comprehensive approach in assessing global cervical-pelvic relationships and the radiographical parameters that effect health-related quality of life scores are not well-defined. Cervical alignment may be important in assessment and treatment of cervical myelopathy. Future work should concentrate on correlation of cervical alignment parameters to disability scores and myelopathy outcomes. SUMMARY STATEMENTS: STATEMENT 1: Cervical sagittal alignment (cervical SVA and kyphosis) is related to thoracolumbar spinal pelvic alignment and to T1 slope. STATEMENT 2: When significant deformity is clinically or radiographically suspected, regional cervical and relative global spinal alignment should be evaluated preoperatively via standing 3-foot scoliosis X-rays for appropriate operative planning. STATEMENT 3: Cervical sagittal alignment (C2-C7 SVA) is correlated to regional disability, general health scores and to myelopathy severity. STATEMENT 4: When performing decompressive surgery for CSM, consideration should be given to correction of cervical kyphosis and cervical sagittal imbalance (C2-C7 SVA) when present.

Pathophysiology and natural history of cervical spondylotic myelopathy.

Abstract: Study design This study is a combination of narrative and systematic review. Objective Clinicians who deal with cervical spondylotic myelopathy (CSM) should be up-to-date with the emerging knowledge related to the cascade of pathobiological secondary events that take place under chronic cervical spinal cord compression. Moreover, by performing a systematic review, we aim to (1) describe the natural history and (2) determine potential risk factors that affect the progression of CSM. Summary of background data The pathophysiology, natural history, as well as the factors associated with clinical deterioration have not been fully described in CSM. Methods For the first part of the study, a literature review was performed. To answer key questions 1 and 2 of the second goal, a systematic search was conducted in PubMed and the Cochrane Collaboration Library for articles published between January 1, 1956, and November 7, 2012. We included all articles that described the progression and outcomes of CSM for which no surgical intervention was given. Results By performing a narrative literature review, we found that the assumption that acute traumatic spinal cord injury and CSM share a similar series of cellular and molecular secondary injury events was made in the past. However, recent advances in basic research have shown that the chronic mechanical compression results in secondary injury mechanisms that have distinct characteristics regarding the nature and the temporal profile compared with those of spinal cord injury. For the purpose of the systematic review, 10 studies yielding 16 publications met inclusion criteria for key questions 2 and 3. Moderate-strength evidence related to the natural history of CSM suggests that 20% to 60% of patients will deteriorate neurologically over time without surgical intervention. Finally, there is low-strength evidence indicating that the area of circumferential compression is associated with deteriorating neurological symptoms. Conclusion CSM has unique pathobiological mechanisms that mainly remain unexplored. Although the natural history of CSM can be mixed, surgical intervention eliminates the chances of the neurological deterioration. EVIDENCE-BASED CLINICAL RECOMMENDATIONS: Recommendation Evidence concerning the natural history of CSM suggests that 20% to 60% of patients will deteriorate neurologically over time without surgical intervention. Therefore, we recommend that patients with mild CSM be counseled regarding the natural history of CSM and have the option of surgical decompression explained. Overall strength of evidence Moderate. Strength of recommendation Strong. SUMMARY STATEMENTS: Chronic compression of the spinal cord results in progressive neural cell loss related to secondary mechanisms including apoptosis, neuroinflammation, and vascular disruption.

Predictive factors for proximal junctional kyphosis in long fusions to the sacrum in adult spinal deformity

Abstract: STUDY DESIGN A retrospective study. OBJECTIVE To assess the mechanisms and the independent risk factors associated with proximal junctional kyphosis (PJK) in patients treated surgically for adult spinal deformity with long fusions to the sacrum. SUMMARY OF BACKGROUND DATA The occurrence of PJK may be related to preoperative and postoperative sagittal parameters. The mechanisms and risk factors for PJK in adults are not well defined. METHODS Consecutive patients who underwent long instrumented fusion surgery (≥6 vertebrae) to the sacrum with a minimum of 2 years of follow-up were retrospectively studied. Risk factors included patient factors, surgical factors, and radiographical parameters such as thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis, pelvic tilt, and pelvic incidence. RESULTS Ninety consecutive patients (mean age, 64.5 yr) met inclusion criteria. Radiographical PJK occurred in 37 of the 90 (41%) patients with a mean follow-up of 2.9 years. The most common mechanism of PJK was fracture at the upper instrumented vertebra (UIV) in 19 (51%) patients. Twelve (13%) patients with PJK were treated surgically with proximal extension of the instrumented fusion. Preoperative TK more than 30°, preoperative proximal junctional angle more than 10°, change in LL more than 30°, and pelvic incidence more than 55° were identified as predictors associated with PJK. Achievement of ideal global sagittal realignment (sagittal vertical axis <50 mm, pelvic tilt <20°, and pelvic incidence-LL <±10°) protected against the development of PJK (19% vs. 45%). A multivariate regression analysis revealed changes in LL more than 30°, and preoperative TK more than 30° were the independent risk factors associated with PJK. CONCLUSION Fracture at the UIV was the most common mechanism for PJK. Change in LL more than 30° and pre-existing TK more than 30° were identified as independent risk factors. Optimal postoperative alignment of the spine protects against the development of PJK. A surgical strategy to minimize PJK may include preoperative planning for reconstructions with a goal of optimal postoperative alignment. LEVEL OF EVIDENCE 3.

Change in classification grade by the SRS-Schwab Adult Spinal Deformity Classification predicts impact on health-related quality of life measures: prospective analysis of operative and nonoperative treatment.

Abstract: Study design Multicenter, prospective, consecutive series. Objective To evaluate responsiveness of the Scoliosis Research Society (SRS)-Schwab adult spinal deformity (ASD) classification to changes in health-related quality of life (HRQOL) after treatment for ASD. Summary of background data Ideally, a classification system should describe and be responsive to changes in a disease state. We hypothesized that the SRS-Schwab classification is responsive to changes in HRQOL measures after treatment for ASD. Methods A multicenter, prospective, consecutive series from the International Spine Study Group. Inclusion criteria ASD, age more than 18, operative or nonoperative treatment, baseline and 1-year radiographs, and HRQOL measures (Oswestry Disability Index [ODI], SRS-22, Short Form [SF]-36). The SRS-Schwab classification includes a curve descriptor and 3 sagittal spinopelvic modifiers (sagittal vertical axis [SVA], pelvic tilt, pelvic incidence/lumbar lordosis [PI-LL] mismatch). Changes in modifiers at 1 year were assessed for impact on HRQOL from pretreatment values based on minimal clinically important differences. Results Three hundred forty-one patients met criteria (mean age = 54; 85% females; 177 operative and 164 nonoperative). Change in pelvic tilt modifier at 1-year follow-up was associated with changes in ODI and SRS-22 (total and appearance scores) (P ≤ 0.034). Change in SVA modifier at 1 year was associated with changes in ODI, SF-36 physical component score, and SRS-22 (total, activity, and appearance scores) (P ≤ 0.037). Change in PI-LL modifier at 1 year was associated with changes in SF-36 physical component score and SRS-22 (total, activity, and appearance scores) (P ≤ 0.03). Patients with improvement of pelvic tilt, SVA, or PI-LL modifiers were significantly more likely to achieve minimal clinically important difference for ODI, SF-36 physical component score (SVA and PI-LL only), SRS activity, and SRS pain (PI-LL only). Conclusion The SRS-Schwab classification provides a validated system to evaluate ASD, and the classification components correlate with HRQOL measures. This study demonstrates that the classification modifiers are responsive to changes in disease state and reflect significant changes in patient-reported outcomes. Level of evidence 3.

Comparison of teriparatide and bisphosphonate treatment to reduce pedicle screw loosening after lumbar spinal fusion surgery in postmenopausal women with osteoporosis from a bone quality perspective.

Abstract: Study design Prospective study. Objective To examine the efficacy of teriparatide or bisphosphonate treatment to reduce pedicle screw (PS) loosening after instrumented lumbar posterolateral fusion in postmenopausal women with osteoporosis. Summary of background data Failure of fixation caused by loosening of PSs in osteoporosis is a problem in spinal surgery. Oral administration of bisphosphonate or intermittent injection of parathyroid hormone treatment increases bone mass and reduces the risk of osteoporotic vertebral fractures. Although these treatments may be factor in improving bone quality, a clinical study of the efficacy of bisphosphonate or parathyroid hormone for reducing PS loosening that addresses the quality of the bone marrow and pedicle cortex has not yet been reported. Methods Sixty-two women with osteoporosis diagnosed with degenerative spondylolisthesis were divided into 3 groups: a teriparatide group (daily subcutaneous injection of 20 μg of teriparatide, n = 20), a bisphosphonate group (daily oral administration 2.5 mg of risedronate, n = 20), and a control group (without medication for osteoporosis, n = 22). All patients underwent decompression and 1- or 2-level instrumented posterolateral fusion with a local bone graft. Loosening of PSs and surgical outcome were evaluated radiographically, clinically, and by computed tomography 12 months after surgery. Results At 12-month follow-up, the incidence of PS loosening was 7% to 13% in the teriparatide group, 13% to 26% in the risedronate group, and 15% to 25% in the control group. The incidence of PS loosening in the teriparatide group was significantly lower than that in the risedronate or the control group (P 0.05). Conclusion Our findings suggest that administration of teriparatide increased the quality of the lumbar spine bone marrow and pedicle cortex.

Epidemiological trends in cervical spine surgery for degenerative diseases between 2002 and 2009.

Abstract: Study design Retrospective analysis of a population-based database. Objective To investigate national epidemiological trends of cervical spine surgical procedures from 2002-2009. Summary of background data Anterior cervical fusion (ACF), posterior cervical fusion (PCF), and posterior cervical decompression (PCD) are procedures routinely performed for cervical degenerative pathology. Studies regarding epidemiological trends of these procedures is currently lacking in the literature. Methods Data from the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project was obtained for each year between 2002 and 2009. Patients undergoing ACF, PCF, and PCD for the diagnosis of cervical radiculopathy and myelopathy were identified. Demographics, costs, and mortality were assessed in the surgical subgroups. A P value of 0.001 was used to denote significance. RESULTS.: An estimated 1,323,979 cervical spine surgical procedures were performed between 2002 and 2009. There was a significant upward trend in the mean age of patients undergoing cervical spine surgery during this time period. ACF and PCF cohorts demonstrated statistically significant increases in comorbidities and costs from 2002-2009. The PCF group had the greatest mortality, comorbidities, costs, and longest hospitalizations compared with ACF and PCF cohorts across all time periods. Conclusion Our study demonstrates that cervical spine surgical procedures have increased between 2002 and 2009 (P = 0.001). The primary increase in volume is due to the increasing number of ACFs. Despite older patients with more comorbidities undergoing ACF and PCF procedures, mortality has not changed. However, this patient population trended significant increases in costs during this time period. We hypothesize that these increased costs are due to an increased comorbidity burden in patients undergoing ACF or PCF. Results of this study can be used to set benchmarks for future epidemiological investigations in cervical spine surgery. Level of evidence 4.

Lumbar spine fusion for chronic low back pain due to degenerative disc disease: a systematic review.

Abstract: STUDY DESIGN Systematic literature review. OBJECTIVE To categorize published evidence systematically for lumbar fusion for chronic low back pain (LBP) in order to provide an updated and comprehensive analysis of the clinical outcomes. SUMMARY OF BACKGROUND DATA Despite a large number of publications of outcomes of spinal fusion surgery for chronic LBP, there is little consensus on efficacy. METHODS A MEDLINE and Cochrane database search was performed to identify published articles reporting on validated patient-reported clinical outcomes measures (2 or more of visual analogue scale, Oswestry Disability Index, Short Form [36] Health Survey [SF-36] PCS, and patient satisfaction) with minimum 12 months of follow-up after lumbar fusion surgery in adult patients with LBP due to degenerative disc disease. Twenty-six total articles were identified and stratified by level of evidence: 18 level 1 (6 studies of surgery vs. nonoperative treatment, 12 studies of alternative surgical procedures), 2 level 2, 2 level 3, and 4 level 4 (2 prospective, 2 retrospective). Weighted averages of each outcomes measure were computed and compared with established minimal clinically important difference values. RESULTS Fusion cohorts included a total of 3060 patients. The weighted average improvement in visual analogue scale back pain was 36.8/100 (standard deviation [SD], 14.8); in Oswestry Disability Index 22.2 (SD, 14.1); in SF-36 Physical Component Scale 12.5 (SD, 4.3). Patient satisfaction averaged 71.1% (SD, 5.2%) across studies. Radiographical fusion rates averaged 89.1% (SD, 13.5%), and reoperation rates 12.5% (SD, 12.4%) overall, 9.2% (SD, 7.5%) at the index level. The results of the collective studies did not differ statistically in any of the outcome measures based on level of evidence (analysis of variance, P > 0.05). CONCLUSION The body of literature supports fusion surgery as a viable treatment option for reducing pain and improving function in patients with chronic LBP refractory to nonsurgical care when a diagnosis of disc degeneration can be made.

Incidence, mode, and location of acute proximal junctional failures after surgical treatment of adult spinal deformity.

Abstract: STUDY DESIGN Multicenter, retrospective series. OBJECTIVE To analyze the incidence, mode, and location of acute proximal junctional failures (APJFs) after surgical treatment of adult spinal deformity. SUMMARY OF BACKGROUND DATA Early proximal junctional failures above adult deformity constructs are a serious clinical problem; however, the incidence and nature of early APJFs remain unclear. METHODS A total of 1218 consecutive adult spinal deformity surgeries across 10 deformity centers were retrospectively reviewed to evaluate the incidence and nature of APJF, defined as any of the following within 28 weeks of index procedure: minimum 15° post-operative increase in proximal junctional kyphosis, vertebral fracture of upper instrumented vertebrae (UIV) or UIV + 1, failure of UIV fixation, or need for proximal extension of fusion within 6 months of surgery. RESULTS Sixty-eight APJF cases were identified out of 1218 consecutive surgeries (5.6%). Patients had a mean age of 63 years (range, 26-82 yr), mean fusion levels of 9.8 (range, 4-18), and mean time to APJF of 11.4 weeks (range, 1.5-28 wk). Fracture was the most common failure mode (47%), followed by soft-tissue failure (44%). Failures most often occurred in the thoracolumbar region (TL-APJF) compared with the upper thoracic region (UT-APJF), with 66% of patients experiencing TL-APJF compared with 34% experiencing UT-APJF. Fracture was significantly more common for TL-APJF relative to UT-APJF (P = 0.00), whereas soft-tissue failure was more common for UT-APJF (P < 0.02). Patients experiencing TL-APJF were also older (P = 0.00), had fewer fusion levels (P = 0.00), and had worse postoperative sagittal vertical axis (P < 0.01). CONCLUSION APJFs were identified in 5.6% of patients undergoing surgical treatment of adult spinal deformity, with failures occurring primarily in the TL region of the spine. There is evidence that the mode of failure differs depending on the location of UIV, with TL failures more likely due to fracture and UT failures more likely due to soft-tissue failures.

Complications after 147 consecutive vertebral column resections for severe pediatric spinal deformity: A multicenter analysis

Abstract: Study Design. Retrospective multicenter review. Objective. Determine the definition, indications, results, and outcomes, focusing on complications of vertebral column resection (VCR) for severe pediatric spinal deformity. Summary of Background Data. The strict definition of the VCR procedure, indications, results, outcomes, and the numerous, potentially serious complications are unknown or controversial, and a large multicenter review has never been performed. Methods. A total of 147 patients treated by 7 pediatric spinal deformity surgeons were reviewed—seventy-four females and 73 males, with an average age of 13.7 years, an average of 1.6 (range, 1–5) vertebrae resected, and an average follow-up of 17 months (range, 0.5–64 mo). The strict definition of VCR used was a “3-column circumferential vertebral osteotomy creating a segmental defect with sufficient instability to require provisional instrumentation.” Results. Indications for a VCR were divided into 5 diagnostic categories: kyphoscoliosis (n = 52), severe scoliosis (n = 37), congenital deformity (n = 28), global kyphosis (n = 17), and angular kyphosis (n = 13). Eighty-four primary and 63 revision patients with 174 operative procedures, 127 posterior-only (17 staged), and 20 patients combined anterior-posterior (10 staged) were reviewed. Average preoperative upright, flexibility, and postoperative Cobb measures (% correction or average kyphosis decrease) were kyphoscoliosis: 91°, 65°, 44° (51% coronal), 104°, 81°, and 47° (decrease, 57° sagittal); severe scoliosis: 104°, 78°, and 33° (67%); congenital deformity: 47°, 38°, 22° (46% coronal), 56°, 48°, and 32° (decrease, 24° sagittal); global kyphosis: 101°, 79°, and 47° (decrease, 54°); and angular kyphosis: 88°, 90°, and 38° (decrease, 50°), respectively. Operative time averaged 545 minutes (range, 204–1355 min) and estimated blood loss averaged 1610 mL (range, 50–8244 mL) for an average 65% blood volume loss (range, 6%–316%). Eighty-six patients (59%) developed a complication, 39 patients (27%) having an intraoperative neurological event (spinal cord monitoring change or failed wake-up test); however, no patient had complete permanent paraplegia. Conclusion. A total of 147 consecutive pediatric VCRs performed by 7 surgeons demonstrated excellent radiographical correction. However, these complex reconstructions were associated with a 59% complication rate, thus emphasizing the challenging nature of these patients and procedures.

Five-year outcomes of minimally invasive versus open transforaminal lumbar interbody fusion: a matched-pair comparison study.

Abstract: STUDY DESIGN Retrospective analysis of prospectively collected data. OBJECTIVE To compare midterm clinical and radiological outcomes of minimally invasive surgery (MIS) versus open transforaminal lumbar interbody fusion (TLIF). SUMMARY OF BACKGROUND DATA Open TLIF is a proven technique to achieve fusion in symptomatic spinal deformities and instabilities. The possible advantages of MIS TLIF include reduced blood loss, less pain, and shorter hospitalization. To date, there is no published data comparing their midterm outcomes. METHODS From 2004-2007, 40 cases of open TLIF were matched paired with 40 cases of MIS TLIF for age, sex, body mass index, and the levels on which the spine was operated. Oswestry Disability Index, neurogenic symptom score, the 36-Item Short Form Health Survey, and visual analogue scale scores for back and leg pain were obtained before surgery, 6 months, 2 years, and 5 years after surgery. Fusion rates were assessed using Bridwell classification. RESULTS Fluoroscopic time (MIS: 55.2 s, open: 16.4 s, P < 0.001) was longer in MIS cases. Operative time (MIS: 185 min, open: 166 min, P = 0.085) was not significantly longer in MIS cases. MIS had less blood loss (127 mL) versus open (405 mL, P < 0.001) procedures. Morphine use for MIS cases (8.5 mg) was less compared with open (24.2 mg, P = 0.006). Patients who underwent MIS (1.5 d) ambulated earlier than those who underwent open fusion (3 d, P < 0.001). Patients who underwent MIS (3.6 d) had shorter hospitalization than those who underwent open fusion (5.9 d, P < 0.001). Both groups showed significant improvement in Oswestry Disability Index, neurogenic symptom score, back and leg pain, SF-36 scores at 6 months until 5 years with no significant differences between them. Grade 1 fusion was achieved in 97.5% of both groups at 5 years. The overall complication rate was 20% for the open group and 15% for MIS group (P = 0.774), including 4 cases of adjacent segment disease for each group. CONCLUSION MIS TLIF is comparable with open TLIF in terms of midterm clinical outcomes and fusion rates with the additional benefits of less initial postoperative pain, less blood loss, earlier rehabilitation, and shorter hospitalization.

ProDisc-C and anterior cervical discectomy and fusion as surgical treatment for single-level cervical symptomatic degenerative disc disease: five-year results of a Food and Drug Administration study.

Abstract: Study design Randomized controlled trial. Objective Analyze the clinical outcomes at 5 years comparing cervical total disc replacement (TDR) with ProDisc-C (Synthes Spine USA Products; LLC, West Chester, PA) with anterior cervical discectomy and fusion (ACDF). Summary of background data Previous reports of 2- and 4-year results have shown that ProDisc-C, a TDR for surgical treatment of patients experiencing single-level symptomatic cervical disc disease between C3 and C7, is safe and effective. Methods Two hundred nine patients (103 ProDisc-C and 106 ACDF) from 13 sites were randomized and treated. Results including neck disability index, visual analog scale (VAS) neck and arm pain, Short Form-36 (SF-36), neurological examination, device success, adverse event occurrence, and VAS patient satisfaction were analyzed. Results Demographics were similar between the 2 patient groups (ProDisc-C: 42.1 ± 8.4 yr, 44.7% males; ACDF: 43.5 ± 7.1 yr, 46.2% males). Rates of follow-up at 2 years were 98.1% ProDisc-C and 94.8% ACDF, and at 5 years 72.7% ProDisc-C and 63.5% ACDF. For all clinical outcomes for both groups, there was a statistically and clinically significant improvement at 2 and 5 years compared with baseline. At 5 years, ProDisc-C patients had statistically significantly less neck pain intensity and frequency. Both groups scored high VAS satisfaction scores at 5 years, with ProDisc-C 86.56 and ACDF 82.74. There were no reports of device failures or implant migration with ProDisc-C. The ProDisc-C patients maintained motion at their index level. At 5 years, the ProDisc-C patients had a statistically significantly lower rate of reoperation compared with ACDF patients (2.9% vs. 11.3%). Conclusion Five-year results show that TDR with ProDisc-C is a safe and effective treatment of single-level symptomatic cervical disc disease. Clinical outcomes were comparable with ACDF. ProDisc-C patients maintained motion at the index level and had significantly less neck pain intensity and frequency as well as a lower probability of secondary surgery.

Next generation of growth-sparing techniques: preliminary clinical results of a magnetically controlled growing rod in 14 patients with early-onset scoliosis.

Abstract: Study design Prospective nonrandomized study. Objective To report the preliminary results of magnetically controlled growing rod (MCGR) technique in children with progressive early-onset scoliosis. Summary of background data The growing rod (GR) technique is a viable alternative for treatment of early-onset scoliosis. High complication rate is attributed to frequent surgical lengthening. The safety and efficacy of MCGR were recently reported in a porcine model. Methods Multicenter study of clinical and radiographical data of patients who underwent MCGR surgery and at least 3 distractions. Distractions were performed in clinic without anesthesia/analgesics. T1-T12 and T1-S1 heights and the distraction distance inside the actuator were measured after lengthening. Results Fourteen patients (7 girls, 7 boys) with a mean age of 8 years, 10 months (3 yr, 6 mo to 12 yr, 7 mo) had 14 index surgical procedures. Of the 14, 5 had single-rod (SR) surgery and 9 had dual-rod (DR) surgery, with overall 68 distractions. Diagnoses were idiopathic (N = 5), neuromuscular (N = 4), congenital (N = 2), syndromic (N = 2), and neurofibromatosis (N = 1). Mean follow-up was 10 months (5.8-18.2). The Cobb angle changed from 60° to 34° after initial surgery and 31° at latest follow-up. During distraction period, T1-T12 height increased by 7.6 mm for SR (1.09 mm/mo) and 12.12 mm for DR (1.97 mm/mo). T1-S1 height gain was 9.1 mm for SR (1.27 mm/mo) and 20.3 mm for DR (3.09 mm/mo). Complications included superficial infection in 1 SR, prominent implant in 1 DR, and minimal loss of initial distraction in 3 SR after index. Partial distraction loss observed after 14 of the 68 distractions (1 DR and 13 SR) but regained in subsequent distractions. There was no neurological deficit or implant failure. Conclusion Preliminary results indicated MCGR was safe and provided adequate distraction similar to standard GR. DR achieved better initial curve correction and greater spinal height during distraction compared with SR. No major complications were observed during the follow-up.

Effects of using intravenous antibiotic only versus local intrawound vancomycin antibiotic powder application in addition to intravenous antibiotics on postoperative infection in spine surgery in 907 patients.

Abstract: Study design A prospective randomized controlled trial. Objective To assess the ability of local vancomycin powder in controlling postoperative infection in spine surgery. Summary of background data Despite improvements through the use of prophylactic systemic antibiotics, surgical site infections remain a significant problem in spine surgical procedures. Various retrospective and prospective studies have reported the efficacy of local application of vancomycin powder in reducing the infection in animal and human studies. However, there were no randomized control trials that reported on its efficacy. Methods Prospective randomized controls of 907 patients with various spinal pathologies were treated surgically during a period of 18 months. The control group received standard systemic prophylaxis only, whereas the treatment group received vancomycin powder in the surgical wound in addition to systemic prophylaxis. Patient demographics, comorbidities, level of spinal pathology, estimated blood loss, nutritional status, and hemoglobin were recorded. Incidence of infection was the primary outcome evaluated. Results There were 8 infections (1.68%) in the control group (6 instrumented and 2 noninstrumented, 6 deep and 2 superficial) with bacteria cultured in 3 (1 Escherichia coli and 2 Staphylococcus aureus). In the treatment group, 7 infections (1.61%) were observed (6 instrumented and 1 noninstrumented surgical procedures, 6 deep and 1 superficial) with bacteria cultured in 3 (1 Staphylococcus aureus and 2 Klebsiella). No adverse effects were observed from the use of vancomycin powder. Statistically no significant difference was seen in infection rate between the treatment group and control group. Conclusion The local application of vancomycin powder in surgical wounds did not significantly reduce the incidence of infection in patients with surgically treated spinal pathologies. The use of vancomycin powder may not be effective when incidence of infection is low.

Anterior versus posterior surgical approaches to treat cervical spondylotic myelopathy: Outcomes of the prospective multicenter AOSpine north America CSM study in 264 patients

Abstract: STUDY DESIGN A prospective observational multicenter study. OBJECTIVE To help solve the debate regarding whether the anterior or posterior surgical approach is optimal for patients with cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA The optimal surgical approach to treat CSM remains debated with varying opinions favoring anterior versus posterior surgical approaches. We present an analysis of a prospective observational multicenter study examining outcomes of surgical treatment for CSM. METHODS A total of 278 subjects from 12 sites in North America received anterior/posterior or combined surgery at the discretion of the surgeon. This study focused on subjects who had either anterior or posterior surgery (n = 264, follow-up rate, 87%). Outcome measures included the modified Japanese Orthopedic Assessment scale, the Nurick scale, the Neck Disability Index, and the Short-Form 36 (SF-36) Health Survey version 2 Physical and Mental Component Scores. RESULTS One hundred and sixty-nine patients were treated anteriorly and 95 underwent posterior surgery. Anterior surgical cases were younger and had less severe myelopathy as assessed by mJOA and Nurick scores. There were no baseline differences in Neck Disability Index or SF-36 between the anterior and posterior cases. Improvement in the mJOA was significantly lower in the anterior group than posterior group (2.47 vs. 3.62, respectively, P < 0.01), although the groups started at different levels of baseline impairment. The extent of improvement in the Nurick Scale, Neck Disability Index, SF-36 version 2 Physical Component Score, and SF-36 version 2 Mental Component Score did not differ between the groups. CONCLUSION Patients with CSM show significant improvements in several health-related outcome measures with either anterior or posterior surgery. Importantly, patients treated with anterior techniques were younger, with less severe impairment and more focal pathology. We demonstrate for the first time that, when patient and disease factors are controlled for, anterior and posterior surgical techniques have equivalent efficacy in the treatment of CSM. LEVEL OF EVIDENCE 3.

A prospective, randomized, controlled clinical investigation comparing PCM cervical disc arthroplasty with anterior cervical discectomy and fusion. 2-year results from the US FDA IDE clinical trial.

Abstract: Study design Prospective, multicenter, randomized Food and Drug Administration approved investigational device exemption clinical trial. Objective To evaluate the safety and effectiveness of the PCM Cervical Disc compared with anterior cervical discectomy and fusion (ACDF) in the treatment of patients with degenerative spondylosis and neurological symptoms at 1 level between C3-C4 and C7-T1. Summary of background data Cervical disc arthroplasty in the treatment of symptomatic cervical spondylosis has been studied in other series. The PCM Cervical Disc is a nonconstrained motion-sparing alternative to ACDF. Methods Patients 18 to 65 years of age with single-level symptomatic cervical spondylosis with radiculopathy and/or myelopathy unresponsive to nonoperative treatment were enrolled, including patients with prior nonadjacent or adjacent single-level fusions. The per-protocol patient sample at 2 years included 342 patients (189 PCM, 153 ACDF). Longitudinal outcomes were comparatively evaluated. Results At 2 years postoperatively, clinical measures-neck and arm pain visual analogue scale, Neck Disability Index (NDI), SF-36, and neurological status-were significantly improved from preoperative baselines in both groups. Mean NDI score at 2 years was significantly lower in PCM group (P = 0.029). There were no statistical differences between groups in rates of surgery-related serious adverse events (5.6% PCM, 7.4% ACDF) or secondary surgical procedures (5.2% PCM, 5.4% ACDF). Patients with PCM reported lower dysphagia scores (8.8/100 vs. 12.1/100; P = 0.045) and higher patient satisfaction (82.8/100 vs. 81.4/100). Overall success, a composite endpoint including minimum 20% NDI improvement, no major complications, no neurological worsening, no secondary surgical procedures, and meeting radiographical criteria of motion for PCM and fusion for ACDF, was significantly greater in the PCM group (75.1% vs. 64.9%; P = 0.020). Conclusion The treatment of symptomatic single-level cervical spondylosis with PCM achieves clinical outcomes that are at least equivalent to ACDF while maintaining motion. At 2 years, patients with PCM had lower NDI scores, statistically lower rate of prolonged dysphagia, greater patient satisfaction, and superior overall success.

Body mass index as a risk factor for developing chronic low back pain: a follow-up in the Nord-Trøndelag Health Study.

Abstract: Study design A population-based, prospective cohort study. Objective To determine whether overweight, obesity, or more generally an elevated body mass index (BMI) increase the probability of experiencing chronic low back pain (LBP) after an 11-year period, both among participants with and without LBP at baseline. Summary of background data Chronic LBP is a common disabling disorder in modern society. Cross-sectional studies suggest an association between an elevated BMI and LBP, but it is not clear whether this is a causal relationship. Methods Data were obtained from the community-based HUNT 2 (1995-1997) and HUNT 3 (2006-2008) studies of an entire Norwegian county. Participants were 8733 men and 10,149 women, aged 30 to 69 years, who did not have chronic LBP at baseline, and 2669 men and 3899 women with LBP at baseline. After 11 years, both groups indicated whether they currently had chronic LBP, defined as pain persisting for at least 3 months continuously during the last year. Results A significant positive association was found between BMI and risk of LBP among persons without LBP at baseline. The odds ratio for BMI 30 or more versus BMI less than 25 was 1.34 (95% confidence interval [CI], 1.08-1.67) for men and 1.22 (95% CI, 1.03-1.46) for women, in analyses adjusted for age, education, work status, physical activity at work and in leisure time, smoking, blood pressure, and serum lipid levels. A significant positive association was also established between BMI and recurrence of LBP among women. LBP status at baseline had negligible influence on subsequent change in BMI. Conclusion High values of BMI may predispose to chronic LBP 11 years later, both in individuals with and without LBP. The association between BMI and LBP is not explained by an effect of LBP on later change in BMI.

Nationwide trends in the surgical management of lumbar spinal stenosis.

Abstract: STUDY DESIGN Retrospective analysis using national administrative data. OBJECTIVE This study presents US nationwide trends in the surgical management of patients with lumbar spinal stenosis (LSS) with and without coexisting spondylolisthesis and scoliosis from 2004 to 2009. SUMMARY OF BACKGROUND DATA Lack of consensus and wide variability exists in surgical decision making for patients with LSS. METHODS Data were obtained from the Nationwide Inpatient Sample, a database developed as part of the Healthcare Cost and Utilization Project. All discharged patients with a primary diagnosis of LSS were identified. Three subgroups were studied: (1) LSS alone, (2) LSS with spondylolisthesis, and (3) LSS with scoliosis. Surgical treatment was divided into 3 groups: (1) decompression only (laminectomy, discectomy), (2) simple fusion (1-2 disc levels, single approach), and (3) complex fusion (>2 disc levels or a combined posterior and anterior approach). RESULTS Between 2004 and 2009, national estimates for the annual number of discharged inpatients with a primary diagnosis of LSS increased from 94,011 (population rate, [the age adjusted population rate per 100,000] 32.1) to 102,107 (population rate, 33.3). The rate of decompressions decreased from 58.5% to 49.2% for discharged patients with LSS from 2004 to 2009 (P < 0.05), whereas the rate of simple fusions increased from 21.5% to 31.2% (P < 0.05) and the rate of complex fusions did not change at 6.7%. From 2004 to 2009, the use of bone morphogenetic protein more than doubled from 14.5% to 33.0% of all fusions, and the use of interbody devices increased from 28.5% to 45.1% (P < 0.05). In 2009, 26.2% of patients with LSS without instability underwent a fusion procedure, while 82.7% of patients with LSS with coexisting spondylolisthesis and 67.6% of patients with coexisting scoliosis underwent a fusion procedure. CONCLUSION This study demonstrates that the rate of simple fusion surgery has increased for treatment of LSS compared with decompression only. LEVEL OF EVIDENCE 4.

Twenty-five years with the biopsychosocial model of low back pain-is it time to celebrate? A report from the twelfth international forum for primary care research on low back pain.

Abstract: Study design An integrated review of current knowledge about the biopsychosocial model of back pain for understanding etiology, prognosis, and interventions, as presented at the plenary sessions of the XII International Forum on LBP Research in Primary Care (Denmark; October 17-19, 2012). Objective To evaluate the utility of the model in reference to rising rates of back pain-related disability, by identifying (a) the most promising avenues for future research in biological, psychological, and social approaches, (b) promising combinations of all 3 approaches, and (c) obstacles to effective implementation of biopsychosocial-based research and clinical practice. Summary of background data The biopsychosocial model of back pain has become a dominant model in the conceptualization of the etiology and prognosis of back pain, and has led to the development and testing of many interventions. Despite this back pain remains a leading source of disability worldwide. Methods The review is a synthesis based on the plenary sessions and discussions at the XII International Forum on LBP Research in Primary Care. The presentations included evidence-based reviews of the current state of knowledge in each of the 3 areas (biological, psychological, and social), identification of obstacles to effective implementation and missed opportunities, and identification of the most promising paths for future research. Results Although there is good evidence for the role of biological, psychological, and social factors in the etiology and prognosis of back pain, synthesis of the 3 in research and clinical practice has been suboptimal. Conclusion The utility of the biopsychosocial framework cannot be fully assessed until we truly adopt and apply it in research and clinical practice. Level of evidence N/A.

Costs associated with treatment of chronic low back pain: an analysis of the UK General Practice Research Database.

Abstract: STUDY DESIGN Retrospective cohort study of health care costs associated with the treatment of chronic low back pain (CLBP) in the United Kingdom OBJECTIVE To assess 12-month health care costs associated with the treatment of CLBP, using the UK General Practice Research Database SUMMARY OF BACKGROUND DATA CLBP is a common health problem METHODS Data were obtained from the General Practice Research Database, a computerized database of UK primary care patient data Patients with CLBP were identified for the study period (January 1, 2007, to December 31, 2009) using diagnostic records and pain relief prescriptions (n = 64,167), and 1:1 matched to patients without CLBP (n = 52,986) on the basis of age, sex, and general practitioner's practice Index date was defined as the first date of CLBP record; the same index date was assigned to matched controls Multivariate analyses were performed to compare resource use costs (2009 values) in the 12 months after the index date between patients with and without CLBP A sensitivity analysis was carried out with a more stringent definition for the control group by excluding a broad range of pain conditions RESULTS Total health care costs for patients with CLBP were double those of the matched controls (£1074 vs £516; P < 005) Of the cost difference, 588% was accounted for by general practitioner's consultations, 223% by referrals to secondary care, and the rest by pain relief medications The sensitivity analysis revealed an even greater cost difference between the 2 groups (£1052 vs £304; P < 005) Because of the use of a retrospective administrative claims database, this study is subject to selection bias between study cohorts, misidentification of comorbidities, and an inability to confirm adherence to therapy or assess indirect costs and costs of over-the-counter medications CONCLUSION Our findings confirm the substantial economic burden of CLBP, even with direct costs only

Prevalence of Adjacent Segment Degeneration after Spine Surgery: A Systematic Review and Meta-analysis.

Abstract: Study design Systematic review of published prevalence of adjacent segment degeneration (ASD) after spine surgery. Objective To evaluate the prevalence of ASD in patients after cervical and lumbar spine surgery. Summary of background data ASD is a common complication after spine surgery in long-term follow-up. A large body of literature has been reported on the topic, but no meta-analysis of the epidemiological data on ASD has been published Methods We searched the MEDLINE until March 2012 published in English language that reported the prevalence of ASD after spine surgery. We determined the ASD rates by calculating proportions and 95% confidence interval (CI) for each study and then pooled the data to derive a pooled proportion and 95% CI. Results A total of 94 studies with 34,716 patients from 19 countries were included. The occurrence of radiograph ASD ranged from 4.8% to 92.2%, and the pooled prevalence was 29.3% (95% CI, 22.7%-35.8%) by the random-effects model. The occurrence of symptoms ASD ranged from 0.0% to 30.3%, and the pooled prevalence was 7.4% (95% CI, 6.4%-8.5%). In cervical position, the occurrence of radiograph ASD and symptoms ASD was 32.8% (95% CI, 17.8%-47.9%) and 6.3% (95% CI, 4.8%-7.8%); in lumbar position, the occurrence of radiograph ASD and symptoms ASD was 26.6% (95% CI, 21.3%-31.9%) and 8.5% (95% CI, 6.4%-10.7%). In the 0.5- to 2- or less, more than 2- to 5- or less, and more than 5- to 20- or less year diagnosis time, the radiograph ASD prevalence was 21.8% (16.0%-27.6%), 33.6% (21.8%-45.4%), and 37.4% (10.7%-64.1%), respectively; and the symptoms ASD prevalence was 6.5% (4.8%-8.1%), 12.1% (8.2%-16.0%), and 3.2% (2.5%-4.0%), respectively. Conclusion Spine surgery is associated with significant risk of ASD. These figures may be useful in the estimation of the burden of the ASD after spine surgery.

Biomechanics of Lumbar Cortical Screw-Rod Fixation Versus Pedicle Screw-Rod Fixation With and Without Interbody Support

Abstract: Study design Seven different combinations of posterior screw fixation, with or without interbody support, were compared in vitro using nondestructive flexibility tests. Objective To study the biomechanical behavior of a new cortical screw (CS) fixation construct relative to the traditional pedicle screw (PS) construct. Summary of background data The CS is an alternative to the PS for posterior fixation of the lumbar spine. The CS trajectory is more sagittally and cranially oriented than the PS, being anchored in the pars interarticularis. Like PS fixation, CS fixation uses interconnecting rods fastened with top-locking connectors. Stability after bilateral CS fixation was compared with stability after bilateral PS fixation in the setting of intact disc and with direct lateral interbody fixation (DLIF) or transforaminal lateral interbody fixation (TLIF) support. Methods Standard nondestructive flexibility tests were performed in cadaveric lumbar specimens, allowing non-paired comparisons of specific conditions from 28 specimens (4 groups of 7) within a larger experiment of multiple hardware configurations. Condition tested and group from which results originated were as follows: (1) intact (all groups); (2) with L3-L4 bilateral PS-rods (group 1); (3) with bilateral CS-rods (group 2); (4) with DLIF (group 3); (5) with DLIF + CS-rods (group 4); (6) with DLIF + PS-rods (group 3); (7) with TLIF + CS-rods (group 2), and (8) with TLIF + PS-rods (group 2). To assess spinal stability, the mean range of motion, lax zone, and stiff zone at L3-L4 were compared during flexion-extension, lateral bending, and axial rotation. Results With intact disc, stability was equivalent after PS-rod and CS-rod fixation, except that PS-rod fixation was stiffer during axial rotation. With DLIF support, there was no significant difference in stability between PS-rod and CS-rod fixation. With TLIF support, PS-rod fixation was stiffer than CS-rod fixation during lateral bending. Conclusion Bilateral CS-rod fixation provided about the same stability in cadaveric specimens as PS-rod fixation regardless of the presence of interbody, TLIF, or DLIF support.

Adult degenerative scoliosis treated with XLIF: clinical and radiographical results of a prospective multicenter study with 24-month follow-up.

Abstract: STUDY DESIGN Prospective, multicenter, single-arm study. OBJECTIVE The objective of this study was to evaluate the clinical and radiographical results of patients undergoing extreme lateral interbody fusion (XLIF), a minimally disruptive lateral transpsoas retroperitoneal surgical approach for the treatment of degenerative scoliosis (DS). SUMMARY OF BACKGROUND DATA Surgery for the treatment of DS has been reported to have acceptable results but is traditionally associated with high morbidity and complication rates. A minimally disruptive lateral transpsoas retroperitoneal surgical approach (XLIF) has become popular for the treatment of DS. This is the first prospective, multicenter study to quantify outcomes after XLIF in this patient population. METHODS A total of 107 patients with DS who underwent the XLIF procedure with or without supplemental posterior fixation at one or more intervertebral levels were enrolled in this study. Clinical and radiographical results were evaluated up to 24 months after surgery. RESULTS Mean patient age was 68 years; 73% of patients were female. A mean of 3.0 (range, 1-6) levels were treated with XLIF per patient. Overall complication rate was low compared with traditional surgical treatment of DS. Significant improvement was seen in all clinical outcome measures at 24 months: Oswestry Disability Index, visual analogue scale for back pain and leg pain, and 36-Item Short Form Health Survey mental and physical component summaries (P < 0.001). Eighty-five percent of patients were satisfied with their outcome and would undergo the procedure again. In patients with hypolordosis, lumbar lordosis was corrected from a mean of 27.7° to 33.6° at 24 months (P < 0.001). Overall Cobb angle was corrected from 20.9° to 15.2°, with the greatest correction observed in patients supplemented with bilateral pedicle screws. CONCLUSION This study demonstrates the use of the XLIF procedure in the treatment of DS. XLIF is associated with good clinical and radiographical outcomes, with a substantially lower complication rate than has been reported with traditional surgical procedures. LEVEL OF EVIDENCE 3.

Spinal manipulative therapy for acute low back pain: an update of the cochrane review.

Abstract: STUDY DESIGN: Systematic review of interventions. OBJECTIVE: To assess the effects of spinal manipulative therapy (SMT) for acute low back pain. SUMMARY OF BACKGROUND DATA: SMT is one of many therapies for the treatment of low back pain, which is a worldwide, extensively practiced intervention. METHODS: An experienced librarian searched for randomized controlled trials (RCTs) in multiple databases up to March 13, 2011. RCTs that examined manipulation or mobilization in adults with acute low back pain (<6-week duration) were included. The primary outcomes were pain, functional status and perceived recovery. Secondary outcomes were return-to-work and quality of life. Two authors independently conducted the study selection, risk of bias assessment and data extraction. GRADE (grading of recommendations assessment, development, and evaluation) was used to assess the quality of the evidence. The effects were examined for SMT versus (1) inert interventions, (2) sham SMT, (3) other interventions, and (4) SMT as adjunct therapy. RESULTS: We identified 20 RCTs (total participants = 2674), 12 (60%) of which were not included in the previous review. In total, 6 trials (30% of all included studies) had a low risk of bias. In general, for the outcomes of pain and functional status, there is low- to very low-quality evidence suggesting no difference in effect for SMT when compared with inert interventions, sham SMT or as adjunct therapy. There was varying quality of evidence (from very low to moderate) suggesting no difference in effect for SMT when compared with other interventions. Data were particularly sparse for recovery, return-to-work, quality of life, and costs of care. No serious complications were observed with SMT. CONCLUSION: SMT is no more effective for acute low back pain than inert interventions, sham SMT or as adjunct therapy. SMT also seems to be no better than other recommended therapies. Our evaluation is limited by the few numbers of studies; therefore, future research is likely to have an important impact on these estimates. Future RCTs should examine specific subgroups and include an economic evaluation.

T1 slope as a predictor of kyphotic alignment change after laminoplasty in patients with cervical myelopathy.

Abstract: STUDY DESIGN: Prospective study. OBJECTIVE: To analyze the effect of T1 slope on kyphotic alignment change after cervical laminoplasty in patients with cervical myelopathy. SUMMARY OF BACKGROUND DATA: Laminoplasty is a posterior method, and maintenance of both preoperative and postoperative lordotic alignment is prerequisite for the successful surgery. Unfortunately, patients who underwent laminoplasty tend to have kyphotic alignment change after operation despite sufficient preoperative lordosis, and such kyphotic alignment change after cervical laminoplasty can reduce surgical outcome and require additional surgery. METHODS: Consecutive patients who underwent cervical laminoplasty for cervical myelopathy were enrolled. Cervical spine lateral radiography in neutral, flexion, and extension were taken before surgery and at 2-year follow-up. Patients were divided into 2 groups according to the preoperative T1 slope, and postoperative cervical alignment change was compared according to the preoperative T1 slope. RESULTS: A total of 51 patients were enrolled in this study. The mean age was 57.2 years (range, 39-88 yr). There were 39 male patients and 12 female patients. There were no differences in age, sex, the presence and type of ossification of posterior longitudinal ligament, and operation level between the patients with higher and lower preoperative T1 slope. Patients with higher preoperative T1 slope had more lordotic preoperative cervical alignment; however, they had more kyphotic alignment changes after laminoplasty (P < 0.001). After univariate logistic regression, only higher preoperative T1 slope was associated with significantly increased odds ratio for postoperative kyphotic alignment changes. CONCLUSION: We hypothesized that kyphotic alignment change by posterior structural injury after cervical laminoplasty would be more marked in patients with high T1 slope, and demonstrated that patients with cervical myelopathy with high T1 slope had more kyphotic alignment changes after cervical laminoplasty at 2-year follow-up.

Reoperation rate after surgery for lumbar herniated intervertebral disc disease: nationwide cohort study.

Abstract: STUDY DESIGN Retrospective cohort study using national health insurance data OBJECTIVE To provide a longitudinal reoperation rate after surgery for lumbar herniated intervertebral disc (HIVD) disease, and to compare the reoperation rates of surgical methods SUMMARY OF BACKGROUND DATA Herniated intervertebral disc disease is the most common cause of lumbar spinal surgery Despite improved surgical techniques and instrumentation, reoperation cannot be avoided The reoperation rates were in the range of 6% to 24% in previous studies A population-based study is less subject to bias; hence, a nationwide longitudinal analysis was warranted METHODS A national health insurance database was used to identify a cohort of patients who underwent first surgery for herniated intervertebral disc disease in 2003 and 18,590 patients were selected Individual patients were followed for at least 5 years through their encrypted unique resident registration number The primary endpoint was any type of second lumbar surgery After adjusting for confounding factors, 5 surgical methods (fusion, laminectomy, open discectomy, endoscopic discectomy, and nucleolysis [including mechanical nucleus decompression]) were compared Open discectomy was used as the reference method RESULTS Open discectomy was the most common procedure (689%) followed by endoscopic discectomy (161%), laminectomy (79%), fusion (39%), and nucleolysis (32%) The cumulative reoperation rate was 54% at 3 months, 74% at 1 year, 9% at 2 years, 105% at 3 years, 121% at 4 years, and 134% at 5 years The reoperation rates were 186%, 147%, 138%, 124%, and 118% after laminectomy, nucleolysis, open discectomy, endoscopic discectomy, and fusion, respectively Compared with open discectomy, the reoperation rate was higher after laminectomy at 3 months, whereas the other surgical methods had similar rates CONCLUSION The cumulative reoperation rate after 5 years was 134% and half of the reoperations occurred during the first postoperative year With the exception of laminectomy, the reoperation rates of the other procedures were not different from that of open discectomy

Association of myelopathy scores with cervical sagittal balance and normalized spinal cord volume: analysis of 56 preoperative cases from the AOSpine North America Myelopathy study.

Abstract: STUDY DESIGN Post hoc analysis of prospectively collected data. OBJECTIVE Development of methods to determine in vivo spinal cord dimensions and application to correlate preoperative alignment, myelopathy, and health-related quality-of-life scores in patients with cervical spondylotic myelopathy (CSM). SUMMARY OF BACKGROUND DATA CSM is the leading cause of spinal cord dysfunction. The association between cervical alignment, sagittal balance, and myelopathy has not been well characterized. METHODS This was a post hoc analysis of the prospective, multicenter AOSpine North America CSM study. Inclusion criteria for this study required preoperative cervical magnetic resonance imaging (MRI) and neutral sagittal cervical radiography. Techniques for MRI assessment of spinal cord dimensions were developed. Correlations between imaging and health-related quality-of-life scores were assessed. RESULTS Fifty-six patients met inclusion criteria (mean age = 55.4 yr). The modified Japanese Orthopedic Association (mJOA) scores correlated with C2-C7 sagittal vertical axis (SVA) (r = -0.282, P = 0.035). Spinal cord volume correlated with cord length (r = 0.472, P < 0.001) and cord average cross-sectional area (r = 0.957, P < 0.001). For all patients, no correlations were found between MRI measurements of spinal cord length, volume, mean cross-sectional area or surface area, and outcomes. For patients with cervical lordosis, mJOA scores correlated positively with cord volume (r = 0.366, P = 0.022), external cord area (r = 0.399, P = 0.012), and mean cross-sectional cord area (r = 0.345, P = 0.031). In contrast, for patients with cervical kyphosis, mJOA scores correlated negatively with cord volume (r = -0.496, P = 0.043) and mean cross-sectional cord area (r = -0.535, P = 0.027). CONCLUSION This study is the first to correlate cervical sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment. It is interesting to note that sagittal balance but not kyphosis is tied to myelopathy score. Future work will correlate alignment changes to cord morphology changes and myelopathy outcomes. SUMMARY STATEMENTS: This is the first study to correlate sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment.

The AOSpine North America Geriatric Odontoid Fracture Mortality Study A Retrospective Review of Mortality Outcomes for Operative Versus Nonoperative Treatment of 322 Patients With Long-Term Follow-up

Abstract: The high incidence of spine fractures in the elderly, coupled with the rapid expansion of this segment of the population in the United States, prompted the recent description of spine fractures in the geriatric population as a serious emerging health care crisis.1 The population of the United States older than 65 years is expected to double to more than 70 million between the years 2000 and 2030,2 and the population older than 85 years is the fastest growing age group, expected to double by 2025 and quintuple by 2050.1,3 Odontoid fractures are among the most common spine fractures in general, but in the elderly, these injuries are the most common isolated spine fracture.4,5 A majority of these are classified as type II fractures on the basis of the classification by Anderson and D'Alonzo.6 A recent report has demonstrated that the number and frequency of type II odontoid fractures, in comparison with other spine injuries, seems to be increasing during the past 2 decades and may correlate with the increasing elderly population.7 There is controversy regarding whether operative or nonoperative management is the best treatment option for elderly patients with type II odontoid fractures.8–12 Type II fractures by definition occur through the base of the dens, which in comparison with the body of the C2 vertebra, has a less robust blood supply and bone quality, and together with its high-strain location renders this fracture more vulnerable to nonunion.13 This risk of nonunion seems to be particularly high in the elderly, in which the rate of pseudarthrosis has been reported to be as high as 85% with nonoperative management.14 In contrast, fusion rates of up to 100% have been reported with posterior C1–C2 instrumentation.15 However, surgical treatment in these often medically compromised patients is also associated with adverse outcomes, with a recent report documenting a mortality rate of 19.2% and major complication rate of 27% in an operatively treated cohort of elderly patients with type II odontoid fractures.16 Adding to the controversy of management of type II odontoid fractures has been uncertainty regarding the clinical significance of chronic fracture nonunion. Reports from Crockard et al17 and Kirankumar et al18 had raised the concern of delayed myelopathy in the setting of nonunion. However, a case series by Hart et al19 suggested that development of delayed myelopathy in the setting of pseudarthrosis of type II odontoid fracture in the elderly to be a rare event. A subsequent report further endorsed a lack of correlation between fracture healing and clinical outcomes.11 Thus, the optimal management of elderly patients with type II odontoid fractures remains controversial, with advocates of both operative and nonoperative approaches.20,21 Our objectives in this study were to evaluate short- and long-term mortality in geriatric patients with type II odontoid fracture and to assess whether these mortality rates differed significantly based on operative versus nonsurgical treatment approach.

Obesity is associated with inferior results after surgery for lumbar spinal stenosis: a study of 2633 patients from the Swedish spine register.

Abstract: Study design A cohort study based on the Swedish Spine Register. Objective To determine the association between body mass index (BMI) and outcome of lumbar spine surgery for spinal stenosis. Summary of background data Several small studies have sought to evaluate the importance of obesity in relation to results after surgery for lumbar spinal stenosis (LSS), but the findings are inconsistent and relatively weak. Methods All patients who underwent surgery for LSS from January 1, 2006, to June 30, 2008, with a completed 2-year follow-up in the Swedish Spine Register were included. Logistic regression was used to assess the association between BMI and different outcomes. Results Of the 2633 patients enrolled, 819 (31%) had normal weight, 1208 (46%) were overweight, and 606 (23%) were obese. On average, all 3 BMI groups achieved significant improvements after surgery. A higher BMI, however, was associated with greater odds of dissatisfaction after surgery and inferior results at the 2-year follow-up. After adjusting for differences in baseline characteristics, the obese group demonstrated inferior function and quality of life as measured by the Oswestry Disability Index (ODI) and the EuroQol Group Index (EQ-5D), respectively. At the 2-year follow-up, obese patients had a mean ODI of 33 (95% confidence interval [CI], 31-34) and mean EQ-5D of 0.56 (95% CI, 0.54-0.59) compared with a mean ODI of 25 (95% CI, 24-26) and mean EQ-5D of 0.64 (95% CI, 0.62-0.66) in the normal weight group. When compared with the normal weight patients, the adjusted odds ratio for dissatisfaction was 1.73 in the obese group (95% CI, 1.36-2.19). Differences between the normal weight and overweight groups were modest and therefore could not be considered clinically relevant. Conclusion Obese patients achieved significant pain reduction, better walking ability, and improved quality of life after surgical treatment of LSS. Nevertheless, obesity was associated with a higher degree of dissatisfaction and poorer outcomes after surgery for LSS.