Faculty Bibliography

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: A key component toward improving surgical outcomes is proper patient selection. Improved selection can occur through exploration of prognostic studies that identify variables which are associated with good or poorer outcomes with a specific intervention, such as lumbar discectomy. To date there are no guidelines identifying key prognostic variables that assist surgeons in proper patient selection for lumbar discectomy. The purpose of this study was to identify baseline characteristics that were related to poor or favourable outcomes for patients who undergo lumbar discectomy. In particular, we were interested in prognostic factors that were unique to those commonly reported in the musculoskeletal literature, regardless of intervention type. METHODS: This retrospective study analysed data from 1,108 patients who underwent lumbar discectomy and had one year outcomes for pain and disability. All patient data was part of a multicentre, multi-national spine repository. Ten relatively commonly captured data variables were used as predictors for the study: (1) age, (2) body mass index, (3) gender, (4) previous back surgery history, (5) baseline disability, unique baseline scores for pain for both (6) low back and (7) leg pain, (8) baseline SF-12 Physical Component Summary (PCS) scores, (9) baseline SF-12 Mental Component Summary (MCS) scores, and (10) leg pain greater than back pain. Univariate and multivariate logistic regression analyses were run against one year outcome variables of pain and disability. RESULTS: For the multivariate analyses associated with the outcome of pain, older patients, those with higher baseline back pain, those with lesser reported disability and higher SF-12 MCS quality of life scores were associated with improved outcomes. For the multivariate analyses associated with the outcome of disability, presence of leg pain greater than back pain and no previous surgery suggested a better outcome. CONCLUSIONS: For this study, several predictive variables were either unique or conflicted with those advocated in general prognostic literature, suggesting they may have value for clinical decision making for lumbar discectomy surgery. In particular, leg pain greater than back pain and older age may yield promising value. Other significant findings such as quality of life scores and prior surgery may yield less value since these findings are similar to those that are considered to be prognostic regardless of intervention type.

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: Cervical drains have historically been used to avoid postoperative wound and respiratory complications such as excessive edema, hematoma, infection, re-intubation, delayed extubation, or respiratory distress. Recently, some surgeons have ceased using drains because they may prolong hospital stay, operative time, or patient discomfort. The objective of this retrospective case-control series is to investigate the effectiveness of postoperative drains following one- and two-level cervical fusions. METHODS: A chart review was conducted at a single institution from 2010-2013. Outcome measures included operative time, hospital stay, estimated blood loss and incidence of wound complications (infection, hematoma, edema, and complications with wound healing or evacuation), respiratory complications (delayed extubation, re-intubation, and respiratory treatment), and overall complications (wound complications, respiratory complications, dysphagia, and other complications). Statistical analyses including independent samples t-test, chi-square, analysis of covariance, and linear regression were used to compare patients who received a postoperative drain to those who did not. RESULTS: The study population included 39 patients who received a postoperative drain and 42 patients who did not. There were no differences in demographics between the two groups. Patients with drains showed increased operative time (100.1 vs 69.3 min, p < 0.001), hospital stay (38.9 vs. 31.7 hrs, p = 0.021), and blood loss (62.7 vs 29.1 mL, p < 0.001) compared to patients without drains. The frequency of wound complications, respiratory complications, and overall complications did not vary significantly between groups. CONCLUSIONS/LEVEL OF EVIDENCE: Cervical drains may not be necessary for patients undergoing one- and two-level cervical fusion. While there were no differences in incidence of complications between groups, patients treated with drains had significantly longer operative time and length of hospital stay. CLINICAL RELEVANCE: This could contribute to excessive costs for patients treated with drains, despite the lack of compelling evidence of the advantages of this treatment in the literature and in the current study.

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!

BACKGROUND CONTEXT: CES represents a surgical indication often requiring emergent surgical decompression. The standard surgical technique for CES management is wide bilateral lumbar laminectomies and discectomies with or without arthrodesis. Prior outcomes studies for CES have focused on the controversial topics of surgical timing and restoration of continence, and have been limited by small cohorts and lack of a control. To our knowledge, no studies have provided nationwide estimates of patient characteristics and procedure-related complication rates after spinal surgery for CES relative to an unaffected population. PURPOSE: To determine patient demographics, incidence of comorbidities and procedure-related complications, and identify risk factors associated with morbidity and mortality after spinal surgery for cauda equina syndrome (CES). STUDY DESIGN/SETTING: Retrospective nationwide database analysis. PATIENT SAMPLE: Nationwide Inpatient Sample data collected between 2001 and 2010 was analyzed. Discharges with procedural codes for lumbar spinal fusion, decompression, or discectomy were included. The CES cohort included diagnoses of CES, and the unaffected cohort included lumbar spinal pathology diagnoses. OUTCOME MEASURES: Measures included patient demographic and hospital system-related data and selected procedure-related complications and comorbidities. METHODS: Descriptive statistics compared patient demographics, incidence of comorbidities and procedure-related complications, and risk factors associated with morbidity and mortality were compared. RESULTS: Discharges for 11,207 CES and 689,799 unaffected patients were identified. Differences between cohorts were found for demographic and hospital data. Average comorbidity indices for the CES cohort were found to be increased (0.23 vs 0.13, p< 0.0001), as well as the incidence of total procedure-related complications (18.63% vs 13.12%, p< 0.0001). In-hospital mortality rate was significantly increased for the CES cohort (0.30% vs 0.08%, p!

BACKGROUND CONTEXT: Lumbar discectomy and laminectomy for patients with intervertebral disc herniations (IDH) is the most common spine surgery performed in the United States with variable reported reoperation rates. Though prospective studies have reported outcomes related to this patient population, few have examined risk factors for reoperation. PURPOSE: To investigate the incidence of re-operation and associated risk factors among the surgically treated patients from the IDH arm of the Spine Patient Outcomes Research Trial (SPORT), randomized and observational cohorts. Our study hypothesis was that specific patient baseline characteristics would emerge as risk factors for re-operation in patients treated surgically for IDH. STUDY DESIGN/SETTING: A retrospective subgroup analysis of the eight-year data from the SPORT trial. PATIENT SAMPLE: 810 patients who underwent surgery for IDH. OUTCOME MEASURES: Incidence of re-operation, risk factors. METHODS: A retrospective subgroup analysis was performed on surgically treated patients enrolled in the IDH arm of the multicenter SPORT trial, randomized and observational cohorts. Patients included in the IDH arm had radicular pain for at least six weeks, clinical evidence of nerveroot irritation, and imaging showing a disc herniation at a level and side consistent with the patient's symptoms. In our subgroup analysis patients were stratified into no re-operation versus re-operation. Baseline characteristics were analyzed using a multivariate regression analysis based on data collected from patients at eight years postoperatively. A Cox regression model Stepwise Method was implemented in SAS with p=0.10 significant for entry and p=0.05 significant for retention to the model with calculation of hazard ratios (HR). RESULTS: At eight years, the re-operation rate was 14.6% with 691 having no re-operation and 119 in the re-operation group. Forty-eight (40%) patients underwent re-operation within the first year, 66 (55%) at two years, 85 (71%) at four years, 1!

BACKGROUND CONTEXT: The pelvic incidence minus lumbar lordosis (PI-LL) is an important preoperative planning tool and a useful postoperative gauge of adequate correction in lumbar flatback deformity. In patients who have had prior interbody fusion at L5-S1, the exact plane of the S1 endplate can be blurred, creating error in the assessment of PILL. The T1 Pelvic angle (TPA), a direct measure of global spinopelvic alignment, correlates with HRQOL but it may not be measureable on all intraoperative radiographs. This study introduces the lumbar pelvic angle (LPA), a novel parameter of lumbopelvic alignment, which can be more readily measured on intraoperative imaging. LPA, the lumbar component of the TPA, creates part of the fan of spinopelvic alignment. PURPOSE: To investigate the relationship of the LPA (angle of a line from the center of L1 to the femoral heads (FH) and a line from the FH to the center of the S1 endplate) and other established radiographic measures of sagittal alignment such as PI-LL and to correlate these parameters with health related quality of life (HRQOL) measures. To determine targets for correction and postoperative outcomes using the LPA measure. STUDY DESIGN/SETTING: Multicenter, prospective database. PATIENT SAMPLE: 852 patients with adult spinal deformity. OUTCOME MEASURES: Oswestry Disability Index (ODI), Scoliosis Research Society (SRS)-22, and Short-Form (SF)-36 Physical Component Score (PCS). METHODS: Multicenter, prospective, analysis of adult spinal deformity (ASD) patients. Inclusion criteria were age>18, and any of the following: scoliosis Cobb angle >20degree, SVA>5 cm, thoracic kyphosis>60degree, and PT greater than 25degree. Baseline and 2-yr follow-up with radiographic and HRQOL outcomes were evaluated. RESULTS: 852 ASD patients (407 operative) were included (mean age 53.7). Baseline LPA correlated with PI-LL (r=0.79), PT (r=0.78), TPA (r=0.82) and SVA (r=0.61) (all p<0.001).PI-LL, LPA and TPA correlated with ODI (r=0.42/0.29/0.45), SF36 PCS (-0.43/-0.28/!

BACKGROUND CONTEXT: Targets for adult spinal deformity (ASD) correction have been proposed including SVA<5cm, PT<20degree, PI-LL< 9degree. A novel radiographic parameter of sagittal alignment, the TPA, has been proposed with a postoperative target of less than 15 degrees. TPA simultaneously accounts for both truncal inclination and pelvic retroversion and does not vary based on the extent of pelvic retroversion or patient support in standing. Published alignment targets are based on baseline HRQOL and radiographic data. There are few reports correlating postoperative corrections and HRQOL to confirm such proposed targets. PURPOSE: To investigate postoperative alignment parameters and HRQOL to determine the validity of ASD targets of correction. STUDY DESIGN/SETTING: Multicenter, prospective database. PATIENT SAMPLE: 844 patient ASD patients at baseline, 407 ASD patient at 2 years. OUTCOME MEASURES: Oswestry Disability Index (ODI), Scoliosis Research Society (SRS)-22, and Short-Form (SF)-36 Physical Component Score (PCS). METHODS: Multicenter, prospective, analysis of ASD patients. Inclusion criteria were age>18, and any of the following: scoliosis Cobb angle >20degree, SVA>5 cm, thoracic kyphosis>60degree, and PT greater than 25degree. Baseline and 2-yr follow-up radiographic and HRQL outcomes were evaluated. RESULTS: A total of 844 ASD patients were included in the baseline analysis, and 407 in the 2 years analysis. Baseline and 2-year TPA correlated with PT (r=0.92/0.91), PI-LL (r=0.89/0.86) and SVA (r=0.83/0.75) (all, p<0.001). Baseline TPA, PI-LL, PT and SVA correlated with ODI (r=0.45/0.42/0.35/0.47), SF36 PCS and SRS with all p<0.001. At 2-year follow up, TPA, PI-LL, PT and SVA correlated more weakly with ODI (r=0.28/0.25/0.20/0.32), SF36 PCS and SRS all with p<0.001. Utilizing a linear regression analysis, the thresholds for pre- and post-treatment severe disability were 20.6degree and 18.2degree for TPA, 5.1 and 3.8cm for SVA and 12.6degree and 4.9degree for PI-LL. Thresholds for mild d!