Faculty Bibliography

STUDY DESIGN/METHODS:Multicenter database review of consecutive adult spinal deformity (ASD) patients. OBJECTIVE:The aim of this study was to identify associations between changes in spinopelvic parameters and cervical alignment after thoracolumbar arthrodesis for ASD. SUMMARY OF BACKGROUND DATA/BACKGROUND:Reciprocal cervical changes occur after instrumented thoracic spinal arthrodesis. The timing and relationship of these changes to sagittal alignment and upper instrumented vertebra (UIV) selection are unknown. METHODS:In 171 ASD patients treated with thoracolumbar arthrodesis from 2008 to 2012, we assessed changes from baseline to 6-week, 1-year, and 2-year follow-up in C2-C7 sagittal vertical axis (SVA), T1 slope, and C2-C7 lordosis. We used multivariate models to analyze associations between these parameters and UIV selection (T9 or distal vs. proximal to T9) and changes at each time point in thoracic kyphosis (TK), lumbar lordosis (LL), C7-S1 SVA, pelvic incidence, pelvic tilt, and sacral slope. RESULTS:Two-year changes in C2-C7 SVA and T1 slope were significantly associated with baseline to 6-week changes in TK and LL and with UIV selection. Baseline to 2-year changes in C2-C7 lordosis were associated with baseline to 6-week changes in C7-S1 SVA (P = 0.004). Most changes in C2-C7 SVA occurred during the first 6 weeks postoperatively (mean 6-week change in C2-C7 SVA: 2.7 cm, 95% confidence interval [CI]: 0.7-4.7 cm; mean 2-year change in SVA: 2.3 cm, 95% CI: -0.1 to 4.6 cm). At 2 years, on average, there was decrease in C2-C7 lordosis, most of which occurred during the first 6 weeks postoperatively (mean 6-week change: -3.2°, 95% CI: -4.8° to -1.2°; mean 2-year change: -1.3°, 95% CI: - 3.2° to 0.5°). CONCLUSION/CONCLUSIONS:After thoracolumbar arthrodesis, reciprocal changes in cervical alignment are associated with postoperative changes in TK, LL, and C7-S1 SVA and with UIV selection. The largest changes occur during the first 6 weeks and persist during 2-year follow-up. LEVEL OF EVIDENCE/METHODS:3.

OBJECTIVE:Cervical deformity (CD) is difficult to define due to the high variability in normal cervical alignment based on postural- and thoracolumbar-driven changes to cervical alignment. The purpose of this study was to identify whether patterns of sagittal deformity could be established based on neutral and dynamic alignment, as shown on radiographs. METHODS:This study is a retrospective review of a prospective, multicenter database of CD patients who underwent surgery from 2013 to 2015. Their radiographs were reviewed by 12 individuals using a consensus-based method to identify severe sagittal CD. Radiographic parameters correlating with health-related quality of life were introduced in a two-step cluster analysis (a combination of hierarchical cluster and k-means cluster) to identify patterns of sagittal deformity. A comparison of lateral and lateral extension radiographs between clusters was performed using an ANOVA in a post hoc analysis. RESULTS:Overall, 75 patients were identified as having severe CD due to sagittal malalignment, and they formed the basis of this study. Their mean age was 64 years, their body mass index was 29 kg/m2, and 66% were female. There were significant correlations between focal alignment/flexibility of maximum kyphosis, cervical lordosis, and thoracic slope minus cervical lordosis (TS-CL) flexibility (r = 0.27, 0.31, and -0.36, respectively). Cluster analysis revealed 3 distinct groups based on alignment and flexibility. Group 1 (a pattern involving a flat neck with lack of compensation) had a large TS-CL mismatch despite flexibility in cervical lordosis; group 2 (a pattern involving focal deformity) had focal kyphosis between 2 adjacent levels but no large regional cervical kyphosis under the setting of a low T1 slope (T1S); and group 3 (a pattern involving a cervicothoracic deformity) had a very large T1S with a compensatory hyperlordosis of the cervical spine. CONCLUSIONS:Three distinct patterns of CD were identified in this cohort: flat neck, focal deformity, and cervicothoracic deformity. One key element to understanding the difference between these groups was the alignment seen on extension radiographs. This information is a first step in developing a classification system that can guide the surgical treatment for CD and the choice of fusion level.

Study Design/UNASSIGNED:Retrospective cohort study. Objective/UNASSIGNED:Factors that predict outcomes for adult cervical spine deformity (ACSD) have not been well defined. To compare ACSD patients with best versus worst outcomes. Methods/UNASSIGNED:This study was based on a prospective, multicenter observational ACSD cohort. Best versus worst outcomes were compared based on Neck Disability Index (NDI), Neck Pain Numeric Rating Scale (NP-NRS), and modified Japanese Orthopaedic Association (mJOA) scores. Results/UNASSIGNED:= .008). Conclusions/UNASSIGNED:Factors distinguishing best and worst ACSD surgery outcomes included patient, surgical, and radiographic factors. These findings suggest areas that may warrant greater awareness to optimize patient counseling and outcomes.

OBJECTIVE:Cervical deformity (CD) correction is clinically challenging. There is a high risk of developing complications with these highly complex procedures. The aim of this study was to use baseline demographic, clinical, and surgical factors to predict a poor outcome following CD surgery. METHODS:The authors performed a retrospective review of a multicenter prospective CD database. CD was defined as at least one of the following: cervical kyphosis (C2-7 Cobb angle > 10°), cervical scoliosis (coronal Cobb angle > 10°), C2-7 sagittal vertical axis (cSVA) > 4 cm, or chin-brow vertical angle (CBVA) > 25°. Patients were categorized based on having an overall poor outcome or not. Health-related quality of life measures consisted of Neck Disability Index (NDI), EQ-5D, and modified Japanese Orthopaedic Association (mJOA) scale scores. A poor outcome was defined as having all 3 of the following categories met: 1) radiographic poor outcome: deterioration or severe radiographic malalignment 1 year postoperatively for cSVA or T1 slope-cervical lordosis mismatch (TS-CL); 2) clinical poor outcome: failing to meet the minimum clinically important difference (MCID) for NDI or having a severe mJOA Ames modifier; and 3) complications/reoperation poor outcome: major complication, death, or reoperation for a complication other than infection. Univariate logistic regression followed by multivariate regression models was performed, and internal validation was performed by calculating the area under the curve (AUC). RESULTS:In total, 89 patients with CD were included (mean age 61.9 years, female sex 65.2%, BMI 29.2 kg/m2). By 1 year postoperatively, 18 (20.2%) patients were characterized as having an overall poor outcome. For radiographic poor outcomes, patients' conditions either deteriorated or remained severe for TS-CL (73% of patients), cSVA (8%), horizontal gaze (34%), and global SVA (28%). For clinical poor outcomes, 80% and 60% of patients did not reach MCID for EQ-5D and NDI, respectively, and 24% of patients had severe symptoms (mJOA score 0-11). For the complications/reoperation poor outcome, 28 patients experienced a major complication, 11 underwent a reoperation, and 1 had a complication-related death. Of patients with a poor clinical outcome, 75% had a poor radiographic outcome; 35% of poor radiographic and 37% of poor clinical outcome patients had a major complication. A poor outcome was predicted by the following combination of factors: osteoporosis, baseline neurological status, use of a transition rod, number of posterior decompressions, baseline pelvic tilt, T2-12 kyphosis, TS-CL, C2-T3 SVA, C2-T1 pelvic angle (C2 slope), global SVA, and number of levels in maximum thoracic kyphosis. The final model predicting a poor outcome (AUC 86%) included the following: osteoporosis (OR 5.9, 95% CI 0.9-39), worse baseline neurological status (OR 11.4, 95% CI 1.8-70.8), baseline pelvic tilt > 20° (OR 0.92, 95% CI 0.85-0.98), > 9 levels in maximum thoracic kyphosis (OR 2.01, 95% CI 1.1-4.1), preoperative C2-T3 SVA > 5.4 cm (OR 1.01, 95% CI 0.9-1.1), and global SVA > 4 cm (OR 3.2, 95% CI 0.09-10.3). CONCLUSIONS:Of all CD patients in this study, 20.2% had a poor overall outcome, defined by deterioration in radiographic and clinical outcomes, and a major complication. Additionally, 75% of patients with a poor clinical outcome also had a poor radiographic outcome. A poor overall outcome was most strongly predicted by severe baseline neurological deficit, global SVA > 4 cm, and including more of the thoracic maximal kyphosis in the construct.

STUDY DESIGN/METHODS:Single institution retrospective clinical review. OBJECTIVE:To investigate the relationship between levels fused and clinical outcomes in patients undergoing open and minimally invasive surgical (MIS) lumbar fusion. SUMMARY OF BACKGROUND DATA/BACKGROUND:Minimally invasive spinal fusion aims to reduce the morbidity associated with conventional open surgery. As multilevel arthrodesis procedures are increasingly performed using MIS techniques, it is necessary to weigh the risks and benefits of multilevel MIS lumbar fusion as a function of fusion length. METHODS:Patients undergoing <4 level lumbar interbody fusion were stratified by surgical technique (MIS or open), and grouped by fusion length: 1-level, 2-levels, 3+ levels. Demographics, Charlson Comorbidity Index (CCI), surgical factors, and perioperative complication rates were compared between technique groups at different fusion lengths using means comparison tests. RESULTS:Included: 361 patients undergoing lumbar interbody fusion (88% transforaminal, 14% lateral; 41% MIS). Breakdown by fusion length: 63% 1-level, 22% 2-level, 15% 3+ level. Op-time did not differ between groups at 1-level (MIS: 233 min vs. Open: 227, P = 0.554), though MIS at 2-levels (332 min vs. 281) and 3+ levels (373 min vs. 323) were longer (P = 0.033 and P = 0.231, respectively). While complication rates were lower for MIS at 1-level (15% vs. 30%, P = 0.006) and 2-levels (13% vs. 27%, P = 0.147), at 3+ levels, complication rates were comparable (38% vs. 35%, P = 0.870). 3+ level MIS fusions had higher rates of ileus (13% vs. 0%, P = 0.008) and a trend of increased adverse pulmonary events (25% vs. 7%, P = 0.110). MIS was associated with less EBL at all lengths (all P < 0.01) and lower rates of anemia at 1-level (5% vs. 18%, P < 0.001) and 2-levels (7% vs. 16%, P = 0.193). At 3+ levels, however, anemia rates were similar between groups (13% vs. 15%, P = 0.877). CONCLUSION/CONCLUSIONS:MIS lumbar interbody fusions provided diminishing clinical returns for multilevel procedures. While MIS patients had lower rates of perioperative complications for 1- and 2-level fusions, 3+ level MIS fusions had comparable complication rates to open cases, and higher rates of adverse pulmonary and ileus events. LEVEL OF EVIDENCE/METHODS:3.

Introduction: Orthopaedic surgeons (OS) and neurosurgeons (NS) both perform cervical total disc replacement (cTDR) procedures. This study evaluated disparities in demographics, comorbidities, laboratory values, surgical and hospital-related parameters, and 30-day outcomes between OS and NS patients after single-level elective cTDR.
Method(s): The American College of Surgeons NSQIP database was used to identify single-level elective cTDR patients from 2008 to 2016. Demographics, comorbidities, laboratory values, operative- and hospital-related factors, and 30-day postoperative outcomes were compared between the OS (n = 769) and NS (n = 1,443) groups with univariate analysis. Regression models were developed to find potential predictive factors for 30-day postoperative complications.
Result(s): The OS patients were younger and more likely to be white (all, p <= 0.012). Comorbidities and preoperative laboatory values were mostly comparable, although OS patients has lower rates of diabetes mellitus (4.55% vs 8.04%; p = 0.002) and corticosteroid use (0.65% vs 2.70%; p = 0.001) than NS patients. The OS and NS patients also had comparable operative times (111 vs 112 minutes; p = 0.737), and rates of 30-day complications (1.2% vs 1.1%; p = 0.896), reoperations (0.4% vs 0.7%; p = 0.51), and readmissions (1.2% vs 1.1%; p = 0.841). Patient age was a significant predictor of major complications (odds ratio 1.079; p = 0.019) based on regression analysis, but surgeon specialty was not for any complications (p >= 0.13).
Conclusion(s): Neurosurgeons had a higher operative volume, but 30-day postoperative outcomes between the 2 groups were comparable. Surgeon specialty was not predictive for 30-day postoperative outcomes. Orthopaedic surgeons might be underperforming cTDR compared with neurosurgeons, despite comparable 30-day postoperative outcomes.
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Introduction: Bariatric surgery prior to spine surgery has been shown to reduce medical complication and infection risk in morbidly obese patients. However, long-term impact of irreversible bariatric surgery (bypass, gastrectomy, diversion/switch) on complication rates and outcomes after cervical fusion (CF) for radiculopathy or myelopathy (CR, CM) is unknown.
Method(s): SPARCS was reviewed from 2009-2013 for all obese/morbidly obese patients (Obese). Patients undergoing primary CF for CR or CM were included, and patients undergoing both primary CF and irreversible bariatric surgery were identified. Patients were grouped as obese CF patients with prior bariatric surgery (BAR) or obese CF patients without bariatric surgery (No-BAR), propensity score-matched and analyzed at 90-days and 2-years. Logistic regression was performed to identify predictors for outcomes.
Result(s): 187 patients had <=90-day follow-up (BAR, n=94; No-BAR, n=93); of these, 55 had >=2-year follow-up (n=28/27). Surgical approach was comparable across cohorts. Among 90-day follow-up patients, bariatric-to-CF interval was 2-year for BAR patients. Demographic, LOS, and mortality (0%), were comparable between cohorts. BAR had comparable 90-day rates of individual/overall medical/surgical complication, total complication (3.2 vs 4.3%), readmission (9.6 vs 14%), and revision (9.6 vs 15.1%). Regression revealed BAR did not reduce 90-day adverse outcomes odds. Among patients with 2-year follow-up, bariatric-to-CF interval was 1.4Y for BAR patients; 2-year-readmission was lower for BAR patients (67.9 vs 92.6%). Regression revealed BAR reduced 2-year-readmission odds (OR=0.12, 95% CI: 0.02-0.78), both p<=0.03.
Conclusion(s): Obese/morbidly obese CF patients with CR/CM with prior bariatric surgery incurred comparable outcomes/complications through short-/mid-term follow-up. Primary CF was safe in patients at least 1.4-years after irreversible bariatric surgery.
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The AHRQ (Agency for Healthcare Research and Quality) has requested the correction of the result Tables 1-3 of this study: All stated numbers below 10 shall be modified to read "<10" instead.