Faculty Bibliography

BACKGROUND: Lumbar discectomy and laminectomy in patients with intervertebral disc herniation (IDH) is common, with variable reported reoperation rates. Our study examined which baseline characteristics might be risk factors for reoperation and compared outcomes between patients who underwent reoperation and those who did not. METHODS: We performed a retrospective subgroup analysis of patients from the IDH arm of the Spine Patient Outcomes Research Trial (SPORT) randomized and observational cohorts. We analyzed baseline characteristics and outcomes of patients who underwent reoperation and those who did not with use of data collected from enrollment through eight-years of follow-up after surgery. Follow-up times were measured from the time of surgery, and baseline covariates were updated to the follow-up immediately preceding the time of surgery for outcomes analyses. RESULTS: At eight years, the reoperation rate was 15% (691 no reoperation; 119 reoperation). Sixty-two percent of these patients underwent reoperation because of a recurrent disc herniation; 25%, because of a complication or other factor; and 11%, because of a new condition. The proportion of reoperations that were performed for a recurrent disc herniation ranged from 58% to 62% in the individual years. Older patients were less likely to have reoperation (p = 0.015), as were patients presenting with asymmetric motor weakness at baseline (p = 0.0003). Smoking, diabetes, obesity, Workers' Compensation, and clinical depression were not associated with a greater risk of reoperation. Scores on the Short Form (SF)-36 for bodily pain and physical functioning, the Oswestry Disability Index (ODI), and the Sciatica Bothersomeness Index as well as satisfaction with symptoms had improved less at the time of follow-up in the reoperation group (p < 0.001). CONCLUSIONS: In patients who underwent surgery for IDH, the overall reoperation rate was 15% at the eight-year follow-up. Patients of older age and patients presenting with asymmetric motor weakness were less likely to undergo a reoperation. Less improvement in patient-reported outcomes was noted in the reoperation group. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND CONTEXT: Cervical deformity (CD) is prevalent among patients with adult spinal deformity (ASD). The effect of baseline cervical alignment on achieving optimal thoracolumbar alignment in ASD surgery is unclear. PURPOSE: This study assesses the relationship between preoperative (preop) cervical spinal parameters and global alignment after thoracolumbar ASD surgery at 2-year follow-up. STUDY DESIGN/SETTING: This study is a retrospective review of a multicenter, prospective database. PATIENT SAMPLE: Surgical ASD patients with 2-year follow-up and cervical X-rays were included. OUTCOME MEASURES: The outcome measures were radiographic parameters and self-reported health-related quality-of-life measures (Short-Form 36 [SF-36], Oswestry Disability Index [ODI], and Scoliosis Research Society 22 [SRS-22]). METHODS: Surgical ASD patients of 18 years and older with scoliosis greater than or equal to 20 degrees and one of the following radiographic parameters were included: sagittal vertical axis (SVA) greater than or equal to 5 cm, pelvic tilt (PT) greater than or equal to 25 degrees , or thoracic kyphosis (TK) greater than 60 degrees . The SRS-Schwab sagittal modifiers (PT, global alignment, and pelvic incidence and lumbar lordosis [PI-LL]) were assessed at 2-year postoperatively as either normal ("0") or abnormal ("+" or "++"). Patients were classified in the aligned group (AG) or malaligned group (MG) at 2-year follow-up if all three sagittal modifiers were normal or abnormal, respectively. Patients were assessed for CD based on the following criteria: C2-C7 SVA greater than 4 cm, C2-C7 SVA less than 4 cm, cervical kyphosis (CL greater than 0), cervical lordosis (CL less than 0), any deformity (C2-C7 SVA greater than 4 cm or CL greater than 0), and both CD (C2-C7 SVA greater than 4 cm and CL greater than 0). Univariate testing was performed using t or chi-square test, looking at the following preop parameters: CD, C2-C7 SVA, C2-T3 SVA, CL, T1 slope (T1S), T1S-CL, C2-T3 angle, LL, TK, PT, C7-S1 SVA, and PI-LL. RESULTS: One hundred four patients met the initial inclusion criteria with 70 in the AG and 34 in MG. Preoperative, patients in the MG had a higher CL (11.7 vs. 4.9, p=.03), higher C2-T3 angle (13.59 vs 4.9 p=.01), higher PT (p<.0001), higher SVA (p<.0001), and higher PI-LL (p<.0001) compared with the AG. Interestingly, the prevalence of CD at baseline was similar for both groups. There was no statistically significant difference among groups in the amount of improvement more than 2 years on the ODI or the Physical Component Summary of SF-36. CONCLUSIONS: Patients with sagittal spinal malalignment associated with significant cervical compensatory lordosis are at increased risk of realignment failure at 2-year follow-up. Assessment of the degree of cervical compensation may be helpful in preop evaluation to assist in realignment outcome prediction.

OBJECT Alignment changes in the cervical spine that occur following surgical correction for thoracic deformity remain poorly understood. The purpose of this study was to evaluate such changes in a cohort of adults with thoracic deformity treated surgically. METHODS The authors conducted a multicenter retrospective analysis of consecutive patients with thoracic deformity. Inclusion criteria for this study were as follows: corrective osteotomy for thoracic deformity, upper-most instrumented vertebra (UIV) between T-1 and T-4, lower-most instrumented vertebra (LIV) at or above L-5 (LIV >/= L-5) or at the ilium (LIV-ilium), and a minimum radiographic follow-up of 2 years. Sagittal radiographic parameters were assessed preoperatively as well as at 3 months and 2 years postoperatively, including the C-7 sagittal vertical axis (SVA), C2-7 cervical lordosis (CL), C2-7 SVA, T-1 slope (T1S), T1S minus CL (T1S-CL), T2-12 thoracic kyphosis (TK), apical TK, lumbar lordosis (LL), pelvic incidence (PI), PI-LL, pelvic tilt (PT), and sacral slope (SS). RESULTS Fifty-seven patients with a mean age of 49.1 +/- 14.6 years met the study inclusion criteria. The preoperative prevalence of increased CL (CL > 15 degrees ) was 48.9%. Both 3-month and 2-year apical TK improved from baseline (p < 0.05, statistically significant). At the 2-year follow-up, only the C2-7 SVA increased significantly from baseline (p = 0.01), whereas LL decreased from baseline (p < 0.01). The prevalence of increased CL was 35.3% at 3 months and 47.8% at 2 years, which did not represent a significant change. Postoperative cervical alignment changes were not significantly different from preoperative values regardless of the LIV (LIV >/= L-5 or LIV-ilium, p > 0.05 for both). In a subset of patients with a maximum TK >/= 60 degrees (35 patients) and 3-column osteotomy (38 patients), no significant postoperative cervical changes were seen. CONCLUSION Increased CL is common in adult spinal deformity patients with thoracic deformities and, unlike after lumbar corrective surgery, does not appear to normalize after thoracic corrective surgery. Cervical sagittal malalignment (C2-7 SVA) also increases postoperatively. Surgeons should be aware that spontaneous cervical alignment normalization might not occur following thoracic deformity correction.

BACKGROUND: Our clinical understanding of os odontoideum (OO) remains incomplete. Congenital and traumatic causes have been proposed and advocated. Clinical presentations range from asymptomatic to axial pain to myelopathy or vertebral-basilar ischemia. A consensus for surgical management exists for those found to have an unstable atlantoaxial complex or symptomatic cranial-vertebral junction compression. OBJECTIVE: To evaluate the clinical presentation and surgical outcomes of patients with OO and an unstable atlantoaxial complex or symptomatic cranial-vertebral junction compression. METHODS: Patients with a diagnosis of OO who underwent surgical management were included. Patients were excluded on the basis of previous C2 fracture, Fielding diagnostic criteria, and inadequate follow-up. History of trauma and presenting symptoms were assessed. Clinical and neurological improvements were measured with the use of patient satisfaction scores and the Japanese Orthopaedic Association scores. Fusion status was documented with the use of radiographs and computed tomographic imaging. RESULTS: Of 279 patients, 112 reported a history of cranial-vertebral junction trauma, whereas 28 were diagnosed with congenital malformations. Clinically, 84.9% of patients presented with myelopathy, with pain presented in 42.6%. Atlantoaxial fixation was performed in 240 patients, occiput-to-C2 fixation in 35 patients, and extended occipito-cervical fixation in 4 patients. Mean follow-up was 40.3 months. Complications were reported in 2.4% of patients. Japanese Orthopaedic Association scores improved from a preoperative mean of 12.4 to 14.8. Two hundred thirty-five patients (77.7%) improved, with 30 patients experiencing no change in symptoms and 14 patients deteriorating. Fusion was achieved in 96.8% of patients. CONCLUSION: Our data reveal that surgical treatment for OO using the indications and techniques delineated is associated with high satisfaction rates, improved functional scores, and high fusion rates with low complication rates. ABBREVIATIONS: AAI, atlantoaxial instabilityJOA, Japanese Orthopaedic AssociationOO, os odontoideum.

STUDY DESIGN: Retrospective review of prospective multicenter database. OBJECTIVE: Quantify the incidence of new onset cervical deformity (CD) after adult spinal deformity surgery of the thoracolumbar spine, identify predictors of development, and determine the impact on outcomes. SUMMARY OF BACKGROUND DATA: High prevalence of residual CD has been identified after surgical treatment of adult spinal deformity. Development of new onset CD is less understood and its clinical impact unclear. METHODS: A total of 215 patients with complete 2-year follow-up and full-length radiographs met inclusion criteria. CD was defined by T1 slope minus Cervical Lordosis (CL) more than 20 degrees , C2-C7 sagittal vertical axis more than 40 mm, or C2-C7 kyphosis more than 10 degrees . Univariate analysis was performed using t tests or tests of proportion. Multivariate logistic regression was used to determine independent predictors of new onset CD. The impact of CD on health-related quality of life and satisfaction was measured using repeated measures mixed models or logistic regression as appropriate, accounting for potential confounders. RESULTS: The overall rate of CD at 2 years after surgery was 63%. Univariate analysis revealed that patients who developed new onset CD postoperatively had higher incidence of diabetes (7.35% vs. 1.28%, P = 0.05), increased preoperative C2-C7 sagittal vertical axis (P = 0.04) and C2 slope (P = 0.038), and smaller diameter rods used at surgery (P = 0.032). Independent predictors of new onset CD at 2 years included: diabetes (odds ratio, 10.49; P = 0.046) and increased preoperative T1 slope minus cervical lordosis (odds ratio, 1.08/ masculine; P = 0.022). Ending instrumentation below T4 was a negative predictor (odds ratio, 0.31; P = 0.019). Patients with and without CD experienced improvements in 2-year 36-Item Short Form Health Survey (P = 0.0001), Oswestry Disability Index (P = 0.0001), and Scoliosis Research Society (P = 0.0001). Rates and overall improvement were similar. CD was not associated with decreased satisfaction (P = 0.28). CONCLUSION: A total of 47.7% of patients without preoperative CD developed new onset postoperative CD after thoracolumbar surgery. Independent predictors of new onset CD at 2 years included diabetes, higher preoperative T1 slope minus cervical lordosis, and ending instrumentation above T4. Significant improvements in health-related quality of life scores occurred despite the development of postoperative CD. LEVEL OF EVIDENCE: 2.

BACKGROUND: Few studies have provided nationwide estimates of patient characteristics and procedure-related complications, or examined postsurgical outcomes for patients with cervical spondylotic myelopathy (CSM) comparatively with respect to surgical approach. The objective of this study is to identify patients at risk for morbidity and mortality directly related with the selected approach, report an overall nation-wide complication rate for each approach against which surgeons can compare themselves, and direct future research to improve patient outcomes. METHODS: Patients surgically treated for CSM were retrospectively identified using ICD-9-CM codes from the Nationwide Inpatient Sample (NIS) database. Four cohorts were compared for demographics and hospital system-related data: anterior (ACDF, ACCF), posterior decompression without fusion, decompression with posterior fusion, and combined anterior-posterior. Multivariate analysis was also used to determine the odds ratio of morbidity and mortality among the cohorts. RESULTS: 54,416 discharges were identified between 2001 and 2010: 34,400 anterior, 9,014 decompression procedures without fusion, 8,741 decompression procedures with posterior fusion, and 2,261 combined anterior-posterior. Groups were statistically different with respect to age, length of hospital stay, mortality, and complications. Groups were statistically different for Deyo score except between posterior decompression only and combined approaches. Using multivariate analysis and adjusting for covariates, the combined (2.74[2.18-3.44]) and laminectomy (1.22[1.04-1.44]) cohorts had an increased risk of mortality when compared to anterior alone. CONCLUSION: These findings are the first to determine the rates and odds of perioperative risks directly related to combined anterior-posterior procedures. This study provides clinically useful data for surgeons to educate patients and direct future research to improve patient outcomes.

BACKGROUND: HGS is a severe deformity most commonly affecting L5-S1 vertebral segment. Treatment available for HGS includes a range of different surgical options: full or partial reduction of translation and/or abnormal alignment and in situ fusion with or without decompression. Various instrumented or non-instrumented constructs are available, and surgical approach varies from anterior/posterior to combined depending on surgeon preference and experience. The aim of this systematic review was to review the literature on lumbosacral high-grade spondylolisthesis (HGS), identify patients at risk for progression to higher-grade slip and evaluate various surgical strategies to report on complications and radiographic and clinical outcomes. METHODS: Systematic search of PubMed, Cochrane and Google Scholar for papers relevant to HGS was performed. 19 articles were included after title, abstract, and full-text review and grouped to analyze baseline radiographic parameters and the effect of surgical approach, instrumentation, reduction and decompression on patient radiographic and clinical outcomes. RESULTS: There is a lack of high-quality studies pertaining to surgical treatment for HGS, and a majority of included papers were Level III or IV based on the JBJS Levels of Evidence Criteria. CONCLUSIONS: Surgical treatment for HGS can vary depending on patient age. There is strong evidence of an association between increased pelvic incidence (PI) and presence of HGS and moderately strong evidence that patients with unbalanced pelvis can benefit from correction of lumbopelvic parameters with partial reduction. Surgeons need to weigh the benefits of fixing the deformity with the risks of potential complications, assessing patient satisfaction as well as their understanding of the possible complications. However, further research is necessary to make more definitive conclusions on surgical treatment guidelines for HGS. LEVEL OF EVIDENCE: II.

BACKGROUND CONTEXT: A high prevalence of residual cervical deformity (CD) has been identified following surgical treatment of adult spinal deformity (ASD). Development of new onset CD is less understood and its clinical impact is unclear. PURPOSE: To quantify the incidence of new onset CD after ASD surgery, identify predictors of development, and determine the impact on outcomes. STUDY DESIGN/SETTING: Retrospective review of a prospective multicenter ASD database. PATIENT SAMPLE: 215 patients > 18 years of age and ASD. OUTCOME MEASURES: Factors for new onset CD and health related quality of life (HRQOL). METHODS: Retrospective review of prospective multicenter database yielded 215 patients (pts) with complete 2-yr follow-up and full length X-ray images including the cervical spine. CD was defined by: T1SCL > 20degree , C2C7 SVA > 40mm, or C2C7 kyphosis > 10degree. Univariate analysis was performed using t-tests or tests of proportion. Multivariate logistic regression was used to determine independent predictors of new CD. The impact of CD on Health Related Quality of Life (HRQL) and satisfaction was measured using repeated measures mixed models or logistic regression as appropriate, accounting for potential confounders. RESULTS: 88/215 ASD pts did not have CD at baseline and 42 of them (47.7%) developed CD at 2 years postop. Univariate analysis revealed that pts who developed new cervical deformity in the postop period had a higher incidence of diabetes (14.29% vs 2.17%, p=0.036) increased preop C2C7 SVA (p=0.04) and C2 slope (p=0.038) and smaller diameter rods used at surgery (p=0.0328). Independent predictors of new CD at 2 yrs included: diabetes (OR 10.49, p=0.046) and increased preop TS-CL (OR 1.08/deg,p=0.027). Ending instrumentation below T4 was a negative predictor of CD (OR 0.31, p=0.019). Pts with and without CD experienced improvements in 2 yr SF-36 (p=0.0001), ODI (p=0.0001) and SRS (p=0.0001). Rates and overall improvement were similar. CD was not associated with decreased satisfact!

BACKGROUND CONTEXT: Cervical deformity (CD) is prevalent among patients with adult spinal deformity (ASD). The effect of baseline cervical alignment and achieving optimal TL alignment in ASD surgery is unclear. PURPOSE: To assesses the relationship between preoperative cervical spinal parameters and global alignment following thoracolumbar ASD surgery at 2-year follow-up. STUDY DESIGN/SETTING: Retrospective review of a multicenter prospective database of surgical ASD patients. PATIENT SAMPLE: 184 > 18 years of age with ASD. OUTCOME MEASURES: C2-C7 SVA, C2-T3 SVA, CL, T1S, T1S-CL, C2-T3 angle, LL, TK, PT, C7-S1 SVA, and PI-LL. METHODS: Using a multicenter prospective database of surgical ASD patients, we included patients with 2-year follow-up and cervical X-ray images. SRS-Schwab sagittal modifiers (PT, GA, PI-LL) were assessed at 2-year postop as either normal ("0") or abnormal ("+" or "++"). Patients were classified in the Aligned Group (AG) or Malaligned Group (MG) if all 3 sagittal modifiers were normal or abnormal, respectively. Patients were assessed for CD based on the following criteria: C2-C7 SVA > 4cm, C2-C7 SVA <4cm, cervical kyphosis (CL > 0), cervical lordosis (CL <0), any deformity (C2C7 SVA > 4cm OR CL > 0), and both CD (C2C7 SVA > 4cm AND CL > 0). Univariate testing was performed using t-tests or chi square, looking at the following preop parameters: CD, C2-C7 SVA, C2-T3 SVA, CL, T1S, T1S-CL, C2-T3 angle, LL, TK, PT, C7-S1 SVA, and PI-LL. RESULTS: 184 patients met initial inclusion criteria with 70 in the AG group and 34 in MG. Preop, patients in the MG group had a higher cervical lordosis (11.7 vs 4.9, p=0.03), higher C2-T3 angle (13.59 vs 4.9 p=0.01), and higher PT (p<0.0001), higher SVA (p<0.0001) and higher PI-LL (p< 0.0001) compared to the AG group. Interestingly, the prevalence of CD at baseline was similar for both groups: MG and AG. There was no statistically significant difference in the amount of improvement over 2 years on the ODI or the SF-36 PCS. CONCLUSIONS: Patien!