Faculty Bibliography

Background: Recent studies suggest non-routine discharge, includingdischarge to inpatient rehab and skilled nursing facilities, is associatedwith increased cost of care. Given the rising prevalence of cervicaldeformity (CD)-corrective surgery and the necessity of value-basedhealthcare, it is important to identify indicators for non-routine discharge in surgical CD patients.Study Design: Retrospective review of prospective, multicenter CDdatabase.Methods: Included: Surgical CD patients (C2-C7 Cobb [10,CL [10, cSVA [4 cm, or CBVA [25) [18 years with discharge and baseline (BL) radiographic data. Non-routine dischargedefined: inpatient rehab or skilled nursing facility. ConditionalInference Decision Trees identified predictors of non-routine discharge, and cut-off points at which predictors have a global effect.A Conditional Variable Importance Table used non-replacementsampling set of 3000 Conditional Inference trees to identify influential patient/surgical factors. Binary logistic regression indicated effectsize of influential factors at significant cut-off points. Means comparison testing assessed the relationship between non-routinedischarge and reop/HRQL outcomes.Results: Included: 138 patients (61 +/- 10 years, 63%F) undergoingCD-corrective surgery (8.2 +/- 4.6 levels; 49% posterior-onlyapproach, 16% anterior-only, 35% combined). 29% of patientsexperienced non-routine discharge (21% inpatient rehab, 8% SNF).BL cervical and upper-cervical malalignment was the strongest predictor of non-routine discharge: [1] C1 slope [14 (OR:8.4 [95%CI:3.1-22.7]), [3] C2 slope [57 (OR: 7.0 [2.6-18.3]), [4] TSCL [57 (OR: 5.9 [2.2-15.9]), [14] C0 slope[-0.66 (OR: 4.2[1.9-9.3]), [15] cSVA [40 mm (OR: 4.6 [2.0-10.9]), [18] McGregor's slope [1.9 (OR: 4.1 [1.7-9.9]). Patient-related predictors ofnon-routine discharge were [2] BL gait impairment (OR: 5.29[2.3-12.4]), [8] age [59 years (OR: 4.3 [1.6-11.1]), [10] apex of CDprimary driver [C7 (OR: 3.9[1.8-8.6]), and [13] admission tosurgical ICU (OR: 5.4 [1.9-14.8]). Experiencing 2 or more complications was predictive of non-routine discharge (OR: 4.2 [1.9-9.2]),but the only specific complications predictive of non-routone discharge were EBL [900 cc (OR: 3.6 [1.7-7.7]) and presence of anyneuro complication (OR: 2.8 [1.8-8.4]). The only surgical predictor ofnon-home discharge was [12] fusion[8 levels (OR: 4.0 [1.8-9.0]).LOS [6 days was also predictive of non-routone discharge (OR: 4.0[1.8-8.9]). There was no relationship between non-routine dischargeand reop within 3 months (P = 0.249), 6 months (P = 0.793), or1 year (P = 0.814) of index procedure. Despite no differences in BLEQ-5D (P = 0.946), non-routine patients had inferior 1-year postopEQ-5D scores (non-routine: 0.75, home: 0.79, P = 0.044).Conclusions: Preop cervical malalignment was a top predictor ofnon-routine discharge in surgical CD patients. Age, driver of deformity, and [8 level fusion also predicted non-routine discharge, andshould be taken into account to improve resource allocation andpatient counseling

Distal junctional kyphosis (DJK) is becoming a morecommonly recognized complication of cervical deformity (CD) surgery. DJK can erode corrections and postoperative cervicalmalalignment has been correlated with poor health outcomes(HRQL). The traditional definition of DJK is arbitrary (DJK angle(DJKA) change\10) and its clinical relevance is unproven. Anew "Severe DJK" definition is explored demonstrating betterspecificity, precision and accuracy with DJK revisions. Severe DJKpatients had the worst cervical alignment by cSVA and C2 Slope(C2S).Hypothesis: The definition of DJK can be improved for more clinicalrelevance.Design: Prospective cohort study.Introduction: Recently, DJK has been described as a complication ofCD correction. However, the current definition of DJK has failed tocorrelate with HRQL or revision rates.Methods: A prospective database of operative CD patients was analyzed. Inclusion criteria were cervical kyphosis [10, cervicalscoliosis [10, cSVA [4 cm or CBVA [25. DJKA was definedas a change from preop to postop kyphosis between LIV to LIV-2.Traditional DJK was defined as DJKA\-10 at any time pointwhile "Severe DJK" was defined as DJKA less than one SD of meanDJKA (-20). Patients without DJK (noDJK) were compared toTraditional and Severe. Cervical alignment was compared betweenthe three groups using ANOVA.Results: 112 patients were included. The mean maximum DJKA forthe whole cohort was-9.00 (SD = 10.0). There were 41 traditionalDJK (35.7%) and 11 Severe DJK (9.8%). Traditional DJK was notassociated with any preop alignment parameters, but Severe DJK wasassociated with an increased CTPA, C2S, cSVA and TSCL at baseline(p< 0.05). TSCL, C2S, and CTPA were increased in the Traditionaland Severe DJK compared to noDJK at 1 year (p< 0.05); postop T1Sand cSVA was increased in the Severe DJK group only. Severe DJKhad more posterior levels fused and more caudal posterior LIV. Therewas no significant difference in HRQL change at 3 months, 6 monthsand 1 year for either DJK group compared to noDJK. The DJKrevision surgery rate was 27.3% for Severe DJK and 8.20% for traditional DJK (p = 0.041). The Severe DJK criteria had betterspecificity (0.92 vs 0.63), precision (0.27 vs 0.12) and accuracy (0.86vs 0.62) for revision surgery. Severe DJK patients had the largest cSVA (61.2, 41.60, 38.56 mm, p<.001) and C2S (52.78, 27.70,24.73, p <.001). The mean time to revision was 4.72 months for thewhole cohort.Conclusions: The modified Severe DJK definition had better specificity, precision and accuracy for DJK revision surgery. Severe DJKpatients had the worst cervical alignment by cSVA and C2 slope withmean alignments well beyond the established thresholds for moderatedisability (Fig. 1)

Summary: In cervical deformity surgery, failure to correct cSVA andC2 slope (C2S) is associated with poor clinical outcomes. Currentsurgical planning and intraoperative measurements are limited tocervical lordosis (CL) correction. By predicting T1 Slope (T1S)change from baseline to 3 month postop and adding a correctionfactor for the change in distal junctional kyphosis angle (DJKA),cSVA and C2S can be predicted more accurately.Hypothesis: While correction of CL is commonly used to predictpost-op alignment, post-op cSVA, and C2S can be predicted betterusing additional variables.Design: Prospective cohort study.Introduction: Cervical malalignment is associated with severe disability. Currently, surgical planning and intraop measurements ofcorrection are limited to CL change. We aim to develop a predictivemodel for postop cSVA C2S and T1S using more than CL change.Methods: A prospective database of operative CD patients wasanalyzed. Inclusion criteria were cervical kyphosis [10, cervicalscoliosis [10, cSVA [4 cm or CBVA [25. The patients wererandomly filtered to include 66.7% of the cohort for model development. Predictive models were developed to estimate post-op T1S,cSVA, and C2S using linear regression. The new predictive equationswere validated in the remaining 33.3% of the cohort.Results: 153 patients with CD met inclusion criteria. T1S changedsignificantly (32.4-35.2, p =.05) from baseline to 3M follow-up.The mean DJKA change was-6.59. 101 patients were included inmodel development. To predict post-opT1S, CLchange and preT1Sexplained 62.4% of the variability of data (R2 = 0.624). By includingDJKA, R2 improved to 0.724. When predicting postop cSVA,CLchange and preop cSVA accounted for 57.2% of variability(R2 = 0.572). With change in DJKA, the R2 improved to 0.661. Themodel was optimized with the change in T1S (R2 = 0.777). Pre-opC2S and CLchange lead to poor predictability in post-op C2S(R2 = 0.348). Using DJKA change, the R2 improved to 0.550. Byincluding DJKA and T1S change, the model was optimized(R2 = 0.926).The predictive equations were applied to the remaining 52 patientsusing the mean DJKA (-6.59) for the DJKA variable and the T1Schange calculated for the predictive model. Predicted postop alignments correlated to postop T1S, cSVA, and C2S (R = 0.712,R = 0.736, and R = 0.584 respectively, p <0.01).Conclusions: Realignment in CD surgery is critical to obtain optimaloutcomes. Current surgical planning of CD does not accurately predict postop cSVA and C2S. A reliable predictive model is presentedfor cSVA and C2S using changes in T1S and DJKA

Cervical deformity (CD) can be debilitating. Surgery forsevere CD has high rates of radiographic and clinical failure. Among66 patients with severe CD, 62% had failure of radiographic correction at 1 year. Failed corrections were associated with worse baselinecervical alignment, male gender and greater intraoperative blood loss.Patients with failed corrections had less improvement in NDI at6 months and 1 year. More patients with successful correctionsattained MCID for NDI (84.2%) at 6 months.Hypothesis: Surgery for severe CD is challenging and there are highrates of radiographic and clinical failure.Design: Prospective cohort study.Introduction: Cervical malalignment is associated with disability.Surgical corrections of severe CD present considerable challenges.Demographic, surgical and postop factors associated with failedradiographic and clinical outcomes have not been well established.Methods: A prospective database of operative CD patients (Inclusioncriteria: cervical kyphosis[10, cervical scoliosis [10, cSVA [4 cm or CBVA [25) was analyzed. Inclusion was restricted tosevere baseline cervical deformities (cSVA [4 cm or C2 Slope(C2S) [20) and 1 year follow-up. Failed surgeries was defined ascSVA [4 cm at 1 year while successful surgery was defined ascSVA\4 cm at 1 year. Successful surgeries were compared to failedones with health related outcome measures, including the MCID forNDI (improvement [7).Results: 66 patients with severe CD met inclusion criteria, including41 failed (62%) surgery and 25 successful. Failed surgery patients hadworse alignment at baseline and 1 year by cSVA, C2S, T1S, TS-CL,and CTPA (p<0.05). Failed surgery patients were more commonlymale (51.2 vs 12%, p <0.01) and had greater intraop blood loss (1.2vs. 44L, p <0.01). History of prior cervical fusion, age, frailty, fusionlength, op-time, use of 3CO, DJK rate, and revision surgery were notassociated with failed surgery. Patients with failed surgery had lessimprovement in clinical outcomes by NDI at 6 months (-8.6 vs-21.7, p <.05) and 1 year (-7.7 vs-17.6, p <.05). Morepatients with successful surgery attained MCID for NDI at 6 months(84.2 vs 51.7%, p = 0.02) but there was no sig difference at 1 year(76.0 vs 56.8%, p = 0.12).Conclusions: Baseline cervical malalignment, male gender and intraop blood loss were associated with failed radiographic outcomes inpatients with severe CD. Failed surgery patients had less improvement in NDI at 6 months and 1 year. More patients with successfulsurgeries attained MCID for NDI at 6 months. In correcting severeCD, surgeons need to obtain optimal radiographic alignment to attainbetter clinical outcomes

Introduction: Cervical deformity (CD) correction has becomeincreasingly complex and challenging. Osteotomies are commonlyperformed to correct sagittal malalignment, however the risks andbenefits of performing a major osteotomy for cervical deformitycorrection have been understudied. The purpose of this study was toinvestigate the risks and benefits of performing a major osteotomy forCD correction.Methods: Retrospective review of a multicenter prospective CDdatabase. CD was defined as at least one of the following: C2-C7Cobb [10, CL [10, cSVA [4 cm, CBVA [25. Patientsstratified based on having a major osteotomy (MAJ-pedicle subtraction osteotomy or vertebral column resection) or minor (MIN).Propensity score matching (PSM) was performed controlling forbaseline cSVA and T1S. Flexibility of the deformity was assessedusing C2-C7 lordosis and T1S change greater than 10 betweenflexion and extension. Independent t-tests and Chi Squared tests wereused to assess differences between MAJ and MIN.Results: 89 CD patients were included (62 years, 65%F). 19 (21.3%)CD patients underwent a MAJ osteotomy. MAJ and MIN had nodifferences in any baseline radiographic parameters, with the exception of cSVA (MAJ: 59.3 mm, MIN: 41.9 mm, p = 0.007). AfterPSM for cSVA, 38 patients were included (60 years, 60%F). 19(21.3%) CD patients underwent a MAJ osteotomy (14 pedicle subtraction osteotomy, 5 vertebral column resection). MAJ patientsunderwent more invasive surgeries, with more levels fused (10.6 vs7.1, p <0.001) and blood loss (1442 cc vs 802 cc, p = 0.036),despite similar operative time and intra-and post-operative complication rates as MIN patients. At 3 M post-op, MAJ and MIN patientshad similar NDI, mJOA, and EQ5D scores, however by 6M and 1Ypost-op MAJ patients reached MCID for NDI less than MIN patients(10.5 vs 57.9%, p = 0.003). Comparing patients with fixed versusnon-fixed CL, MAJ patients with non-fixed lordosis trended towardsimprovement in NDI (p = 0.30) but also trended towards highercomplication (78 vs 43%, p = 0.182) and reoperation rates (44 vs 0%,p = 0.069) than fixed deformities. Rigid deformities trended towardsimprovement in TS-CL (43% improve vs 33%, p = 0.54) and cSVA(14 vs 0%, p = 0.49) for MAJ patients and lower complication rate(MIN most commonly had DJK and reoperation) (43 vs 100%,p = 0.09).Conclusions: Cervical deformity patients who underwent a majorosteotomy had similar clinical outcomes at 3-months but worseclinical outcomes at 6-months and 1-year, assessed by NDI and EQ-5D, as compared with patients with minor osteotomies, in partbecause patients undergoing major osteotomies have more severedeformities and have more prolonged recovery kinetics. Patients withflexible curves showed similar alignment and clinical outcomes butincreased complication risk when undergoing a major osteotomy.Contrarily, patients with rigid deformities who underwent a majorosteotomy trended towards radiographic and clinical improvementand lower rates of DJK and reoperation

STUDY DESIGN/METHODS:Prospective multi-center cohort study with consecutive enrollment OBJECTIVE.: To evaluate pre-operative alignment and surgical factors associated with sub-optimal early post-operative radiographic outcomes following surgery for cervical deformity. SUMMARY OF BACKGROUND DATA/BACKGROUND:Recent studies have demonstrated correlation between cervical sagittal alignment and patient reported outcomes. Few studies have explored cervical deformity correction prospectively, and the factors that result in successful vs. failed cervical alignment corrections remain unclear. METHODS:Adult cervical deformity (ACD) patients included with either cervical kyphosis >10°, cSVA >4 cm, or CBVA >25°. Patients were categorized into failed outcomes group if cSVA >4 cm or TS-CL >20° at 6 months post-operatively. RESULTS:71 ACD patients (mean age 62yrs, 56%Female, 41% revisions) were included. 45 had primary cervical deformities and 26 at the CT junction. 33 (46.4%) had failed radiographic outcomes by cSVA and 46 (64.7%) by TS-CL. Failure to restore cSVA was associated with worse preoperative C2 pelvic tilt angle (CPT: 64.4 vs 47.8°, p = 0.01), worse postoperative C2 Slope (35.0 vs 23.8°, p = .004), TS-CL (35.2 vs 24.9°, p = .01), CPT (47.9 vs 28.2°, p < .001), "+" Schwab modifiers (p = 0.007), revision surgery (p = 0.05) and failure to address the secondary, thoracolumbar driver of the deformity (p = .02). Failure to correct TS-CL was associated with worse preoperative cervical kyphosis (10.4 vs -2.1°, p = .03), CPT (52.6 vs 39.1°, p = .04), worse postoperative C2 Slope (30.2 vs 13.3°, p < .001), cervical lordosis (-3.6 vs -15.1°, p = .01), and CPT (37.7 vs 24.0°, p < .001). Multivariate analysis revealed post-operative DJK associated with sub-optimal outcomes by cSVA (OR- 0.06, CI- 0.01-0.4, p = .004) and TS-CL (OR-0.15, CI- 0.02-0.97, p = .05). CONCLUSIONS:Factors associated with failure to correct the cSVA included revision surgery, worse preop CPT, and concurrent thoracolumbar deformity. Failure to correct the TS-CL mismatch was associated with worse preoperative cervical kyphosis and CPT. Occurrence of early post-operative DJK significantly affects post-operative radiographic outcomes. LEVEL OF EVIDENCE/METHODS:3.

BACKGROUND CONTEXT/BACKGROUND:Obesity as a comorbidity in spine pathology may increase the risk of complications following surgical treatment. The body mass index (BMI) threshold at which obesity becomes clinically relevant, and the exact nature of that effect, remains poorly understood. PURPOSE/OBJECTIVE:Identify the BMI that independently predicts risk of postoperative complications following lumbar spine surgery. STUDY DESIGN/SETTING/METHODS:Retrospective review of the National Surgery Quality Improvement Program (NSQIP) years 2011-2013. PATIENT SAMPLE/METHODS:A total of 31,763 patients were undergoing arthrodesis, discectomy, laminectomy, laminoplasty, corpectomy, or osteotomy of the lumbar spine. OUTCOME MEASURES/METHODS:Complication rates. METHODS:The patient sample was categorized preoperatively by BMI according to the World Health Organization stratification: underweight (BMI <18.5), normal overweight (BMI 20.0-29.9), obesity class 1 (BMI 30.0-34.9), 2 (BMI 35.0-39.9), and 3 (BMI≥40). Patients were dichotomized based on their position above or below the 75th surgical invasiveness index (SII) percentile cutoff into low-SII and high-SII. Differences in complication rates in BMI groups were analyzed by Bonferroni analysis of variance (ANOVA) method. Multivariate binary logistic regression evaluated relationship between BMI and complication categories in all patients and in high-SII and low-SII surgeries. RESULTS:. The odds ratios for any complication (odds ratio [OR] [95% confidence interval {CI}]; obesity 2: 1.218 [1.020-1.455]; obesity 3: 1.742 [1.439-2.110]), infection (obesity 2: 1.335 [1.110-1.605]; obesity 3: 1.685 [1.372-2.069]), and surgical complication (obesity 2: 1.622 [1.250-2.104]; obesity 3: 2.798 [2.154-3.634]) were significantly higher in obesity classes 2 and 3 relative to the normal-overweight cohort (all p<.05). CONCLUSION/CONCLUSIONS:There is a significant increase in complications, specifically infection and surgical complications, in patients with BMI≥35 following lumbar spine surgery, with that rate further increasing with BMI≥40.

OBJECTIVE Given the recent shift in health care toward quality reporting requirements and a greater emphasis on a cost-quality approach, patient stratification with respect to long-term outcomes and the use of health care resources is of increasing value. Stratification tools may be effective if they are simple and evidence based. The authors hypothesize that preoperative patient-reported activity levels might independently predict postoperative outcomes in patients with adult spinal deformity. METHODS This is a retrospective cohort. A total of 575 patients in a prospective adult spinal deformity surgical database were identified with complete data regarding the preoperative level of activity. Answers to question 5 of the Scoliosis Research Society-22r Patient Questionnaire (SRS-22r) were used to stratify patients into active and inactive groups. Outcomes were length of hospital stay (LOS), level of activity, and reaching the minimum clinically important difference (MCID) for SRS-22r domains and the Physical Component Summary (PCS) of the SF-36 at 2 years postoperatively. The 2 groups were compared with respect to several potential confounders. Covariates with p < 0.1 were controlled for. The impact of activity on LOS was assessed using multivariate negative binomial regression analysis. Multivariate logistic regression models additionally controlling for the respective baseline health-related quality of life (HRQOL) scores were used to assess the association between preoperative activity levels and reaching the MCID at 2 years postoperatively. RESULTS A total of 420 (73%) of the 575 patients who met the inclusion criteria had complete data at 2 years postoperatively. The inactive group was more likely to be significantly older, have a higher Charlson Comorbidity Index, worse baseline radiographic deformity, and greater correction of most radiographic parameters. After controlling for possible confounders, the active group had a significantly shorter LOS (incidence risk ratio 0.91, p = 0.043). After adding respective baseline HRQOL scores to the models, active patients were significantly more likely to reach the MCID for the SRS-22r pain domain (OR 1.72, p = 0.026) and PCS (OR 1.94, p = 0.013). Active patients were also significantly more likely to be active at 2 years postoperatively on multivariate analysis (OR 8.94, p < 0.001). CONCLUSIONS The authors' results show that patients who belong to the inactive group are likely to have a longer LOS and lower odds of reaching the MCID in HRQOL or being active at 2 years postoperatively. Inquiring about patients' preoperative activity levels might be a reliable and simple stratification tool in terms of long- and short-term outcomes in ASD patients.

BACKGROUND:A surgical invasiveness index (SII) has been validated in general spine procedures but not adult spinal deformity (ASD). OBJECTIVE:To assess the ability of the SII to determine the invasiveness of ASD surgery and to create and validate a novel ASD index incorporating deformity-specific factors, which could serve as a standardized metric to compare outcomes and risk stratification of different ASD procedures for a given deformity. METHODS:Four hundred sixty-four patients who underwent ASD surgery between 2009 and 2012 were identified in 2 multicenter prospective registries. Multivariable models of estimated blood loss (EBL) and operative time were created using deformity-specific factors. Beta coefficients derived from these models were used to attribute points to each component. Scoring was iteratively refined to determine the R2 value of multivariate models of EBL and operative time using adult spinal deformity-surgical (ASD-S) as an independent variable. Similarly, we determined weighting of postoperative changes in radiographical parameters, which were incorporated into another index (adult spinal deformity-surgical and radiographical [ASD-SR]). The ability of these models to predict surgical invasiveness was assessed in a validation cohort. RESULTS:Each index was a significant, independent predictor of EBL and operative time (P < .001). On multivariate analysis, ASD-S and ASD-SR explained more variability in EBL and operative time than did the SII (P < .001). The ASD-SR explained 21% of the variation in EBL and 10% of the variation in operative time, whereas the SII explained 17% and 3.2%, respectively. CONCLUSION/CONCLUSIONS:The ASD-SR, which incorporates deformity-specific components, more accurately predicts the magnitude of ASD surgery than does the SII.