Faculty Bibliography

Background: For surgical adult spinal deformity (ASD) patients, incorporating restoration of appropriate Roussouly Classificaion shape into surgical planning may improve outcomes. With the introduction and use of the SRS-Schwab ASD classification system, it's important to compare the utility of both classification frameworks as they relate to surgical outcomes.
Purpose(s): Compare outcomes of surgical ASD patients classified by both Roussouly and Schwab systems.
Method(s): Retrospective review of prospective ASD database. ASD patients were grouped by theoretical Roussouly type (1: PI<45-, LL apex below L4; 2: PI<45-, LL apex above L4-L5 space; 3: 45-Result(s): Included: 515 ASD patients (59 +/- 14yrs, 80%F). Preop breakdown of current Roussouly types: Type 1 (10%), Type 2 (54%), Type 3 (24%), Type 4 (12%). Preop mismatch between current and theoretical types was 60%. By 2Y, 16% of patients matched Roussouly types. Matched and Mismatched groups did not differ in rates of reaching MCID for any HRQL metrics by 2Y (all p[0.1). Reop, PJK, and complications did not differ between Matched and Mismatched (all p[0.1), though Mismatched patients showed a trend of increased instrumentation failure (17% vs 26%, p = 0.080). By 2Y, 28% of patients improved in PT Schwab modifier, 37% in SVA, and 46% in PI-LL. Patients that improved in PT modifier reached MCID at higher rates for ODI and SRS Activity by 2Y, and had lower rates of instrumentation failure than those that did not (Table 1). Patients that both Matched Roussouly at 2Y and improved in all Schwab modifiers met MCID for ODI and SRS Activity at higher rates than patients that did not. Roussouly Match patients that improved in Schwab PT met SRS Activity MCID at a higher rate, and had less renal, infection, and neurologic complications than patients that did not. Roussouly Match patients that improved in Schwab SVA also had superior SF-36 scores and fewer cardiopulmonary complications (all p<0.05).
Conclusion(s): For surgical ASD patients, isolated restoration of sagittal spinal shape per the Roussouly system was not associated with superior clinical outcomes or complications by 2Y. In contrast, improvement in PT, per SRS-Schwab system, was associated with improvement in low-back disability by 2Y. Collectively, patients that matched Roussouly type and improved in Schwab modifiers had superior complication and patient-reported outcomes by 2Y. These results indicate concurrent consideration of both classification systems may offer utility in establishing optimal realignment targets

OBJECTIVE:Obesity, a condition that is increasing in prevalence in the United States, has previously been associated with poorer outcomes following deformity surgery, including higher rates of perioperative complications such as deep and superficial infections. To date, however, no study has examined the relationship between preoperative BMI and outcomes of deformity surgery as measured by spine parameters such as the sagittal vertical axis (SVA), as well as health-related quality of life (HRQoL) measures such as the Oswestry Disability Index (ODI) and Scoliosis Research Society-22 patient questionnaire (SRS-22). To this end, the authors sought to clarify the relationship between BMI and postoperative change in SVA as well as HRQoL outcomes. METHODS:The authors performed a retrospective review of a prospectively managed multicenter adult spinal deformity database collected and maintained by the International Spine Study Group (ISSG) between 2009 and 2014. The primary independent variable considered was preoperative BMI. The primary outcome was the change in SVA at 1 year after deformity surgery. Postoperative ODI and SRS-22 outcome measures were evaluated as secondary outcomes. Generalized linear models were used to model the primary and secondary outcomes at 1 year as a function of BMI at baseline, while adjusting for potential measured confounders. RESULTS:Increasing BMI (compared to BMI < 18) was not associated with change of SVA at 1 year postsurgery. However, BMIs in the obese range of 30 to 34.9 kg/m2, compared to BMI < 18 at baseline, were associated with poorer outcomes as measured by the SRS-22 score (estimated change -0.47, 95% CI -0.93 to -0.01, p = 0.04). While BMIs > 30 appeared to be associated with poorer outcomes as determined by the ODI, this correlation did not reach statistical significance. CONCLUSIONS:Baseline BMI did not affect the achievable SVA at 1 year postsurgery. Further studies should evaluate whether even in the absence of a change in SVA, baseline BMIs in the obese range are associated with worsened HRQoL outcomes after spinal surgery.

STUDY DESIGN:Retrospective review of a prospectively collected multicenter database. OBJECTIVES:To evaluate the evolution of surgical treatment strategies, complications, and patient-reported outcomes for adult spinal deformity (ASD) patients. SUMMARY OF BACKGROUND DATA:ASD surgery is associated with high complication rates. Evolving treatment strategies may reduce these risks. METHODS:Adult patients undergoing ASD surgery from 2009 to 2016 were analyzed (n = 905). Preoperative and surgical parameters were compared across years. Subgroup analysis of 436 patients with minimum two-year follow-up was also performed. RESULTS:From 2009 to 2016, there was a significant increase in the mean preoperative age (52 to 63.1, p < .001), body mass index (26.3 to 32.2, p = .003), Charlson Comorbidity index (1.4 to 2.2, p < .001), rate of previous spine surgery (39.8% to 53.1%, p = .01), and baseline disability (visual analog scale [VAS] back and leg pain) scores (p < .01), Oswestry Disability Index, and 22-item Scoliosis Research Society Questionnaire scores (p < .001). Preoperative Schwab sagittal alignment modifiers and overall surgical invasiveness index were similar across time. Three-column osteotomy utilization decreased from 36% in 2011 to 16.7% in 2016. Lateral lumbar interbody fusion increased from 6.4% to 24.1% (p = .004), anterior lumbar interbody fusion decreased from 22.9% to 16.7% (p = .043), and transforaminal lumbar interbody fusion/posterior lumbar interbody fusion utilization remained similar (p = .448). Use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in 2012 was 84.6%, declined to 58% in 2013, and rebounded to 76.3% in 2016 (p = .006). Tranexamic acid use increased rapidly from 2009 to 2016 (13.3% to 48.6%, p < .001). Two-year follow-up sagittal vertical axis, pelvic tilt, pelvic incidence-lumbar lordosis, and maximum Cobb angles were similar across years. Intraoperative complications decreased from 33% in 2010 to 9.3% in 2016 (p < .001). Perioperative (<30 days, <90 days) complications peaked in 2010 (42.7%, 46%) and decreased by 2016 (24.1%, p < .001; 29.6%, p = .007). The overall complication rate decreased from 73.2% in 2008-2014 patients to 62.6% in 2015-2016 patients (p = .03). Two-year health-related quality of life outcomes did not significantly differ across the years (p > .05). CONCLUSIONS:From 2009 to 2016, despite an increasingly elderly, medically compromised, and obese patient population, complication rates decreased. Evolving strategies may result in improved treatment of ASD patients. LEVEL OF EVIDENCE:Level IV.

STUDY DESIGN:Retrospective review of a prospectively collected database. OBJECTIVES:This preliminary investigation sought to identify the quality of care adolescent idiopathic scoliosis (AIS) patients from our large, underserved community had received before presenting at this institution's clinic. SUMMARY OF BACKGROUND DATA:AIS affects 1% to 4% of children between ages 10 and 16. Barriers to health care for patients in underserved populations have not been well studied. METHODS:Patients who visited a single surgeon's clinic for primary AIS between June 2016 and January 2017 were enrolled. Patients had 36-inch full-spine radiographs and completed a survey of demographics, prior AIS care received (screening, bracing, etc), socioeconomic parameters, and patient-reported outcomes (PROs; Scoliosis Research Society [SRS]-30 Questionnaire and Body Image Disturbance Questionnaire [BIDQ]). Parametric and nonparametric analyses were used and percentages and mean/median values were reported. RESULTS:47 patients (age: 15 ± 3 years; 82.7% female) were included. Overall, 25.5% of patients reported a family history of scoliosis, and 42.6% had no prior knowledge of scoliosis. Per Scoliosis Research Society (SRS) recommendations, 15 patients required observation (main Cobb angle: <25°), 22 patients were eligible for bracing (25°-45°), and 10 patients were surgical candidates (>45°). In addition, 21.3% of all patients were never screened for scoliosis; of these, 50% had a main scoliosis curve >25°. Seventy percent of surgical candidates never wore a brace, and 59.3% of screened patients who were eligible for bracing were not braced at initial presentation. Patients who were left unbraced when eligible exhibited worse BIDQ scores (1.7 vs. 1.4, p < .05). CONCLUSIONS:One of five children in our population was never screened for scoliosis, and nearly three of five children did not receive optimal care as recommended by SRS. AIS patients in our inner-city populations are potentially at risk of continuing to experience a significant disadvantage in health care access. LEVEL OF EVIDENCE:Level IV case series.

STUDY DESIGN:Retrospective review of KID Inpatient Database (KID) from 2003, 2006, 2009, and 2012. OBJECTIVES:The aim of this study was to evaluate the impact of advances in spinal surgery on patient outcomes in the treatment of Scheuermann kyphosis (SK). SUMMARY OF BACKGROUND DATA:SK is one of the most common causes of back pain in adolescents. Trends in diagnoses and surgical treatment and approach to SK have not been well described. METHODS:SK patients aged 0-20 years in KID were identified by ICD-9 code 732.0. KID-supplied year- and hospital-trend weights were used to establish prevalence. Patient demographics, surgical details, and outcomes were analyzed with analysis of variance. RESULTS:A total of 1,070 SK patients were identified (33.2% female), with increasing incidence of SK diagnosed from 2003 to 2012 (3.6-7.5 per 100,000, p < .001). The average age of operative patients was 16.1±2.0 years and did not change (16.27-16.06 years, p = .905). The surgical rate has not changed over time (72.8%-72.8%, p = .909). Overall, 96.3% of operative patients underwent fusion, with 82.2% of cases spanning ≥4 levels; in addition, 8.6% underwent an anterior-only surgery, 74.6% posterior-only, and 13.6% combined approach. From 2003 to 2012, rates of posterior-only surgeries increased (62.4%-84.4%, p < .001) whereas the rate of combined-approach surgeries decreased (37.6%-8.8%, p < .001). Overall complication rates for SK surgeries have decreased (2003: 20.9%; 2012: 11.9%, p = .029). Concurrently, the rate of ≥4-level fusions has increased (43.5%-89.6%, p < .001), as well as the use of Smith-Peterson (7.8%-23.6%, p < .001) and three-column osteotomies (0.0%-2.7%, p = .011). In subanalysis comparing posterior to combined approaches, complication rates were significantly different (posterior: 9.88%, combined: 19.46%, p = .005). Patients undergoing a combined approach have a longer length of stay (LOS) than patients undergoing a posterior-only approach (7.8 vs. 5.6 days, p < .001). CONCLUSIONS:Despite unchanged demographics and operative rates in SK, there has been a shift from combined to isolated posterior approaches, with a concurrent increase in levels treated. A combined approach was associated with increased complication rates, LOS, and total charges compared to isolated approaches. Awareness of these inherent differences is important for surgical decision making and patient education. LEVELS OF EVIDENCE:Level III.

STUDY DESIGN:Retrospective review from a single institution. OBJECTIVES:To evaluate intraoperative T1-pelvic angle (TPA), T4PA, and T9PA as predictors of postoperative global alignment after adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA:Malalignment following adult spinal surgery is associated with disability and correlates with health-related quality of life. Preoperative planning and intraoperative verification are crucial for optimal postoperative outcomes. Currently, only pelvic incidence minus lumbar lordosis (PI-LL) mismatch has been used to assess intraoperative correction. METHODS:Patients undergoing ≥4-level spinal fusion with full-length pre-, intra-, and first postoperative calibrated radiographs were included from a single institution. Alignment measurements were obtained for sagittal vertical axis (SVA), PI-LL, TPA, T4PA, and T9PA. The whole cohort was divided into upper thoracic (UT: UIV > T7) and lower thoracic fusions (LT: UIV < T7). Change was assessed between phases, and a subanalysis was included for UT and LT groups to compare alignment changes for differing extent of proximal fusion in the sagittal plane. RESULTS:Eighty patients (mean 63.4 years, 70% female, mean levels fused 11.9) underwent significant ASD correction (ΔPI-LL = 22.1°; ΔTPA = 13.8°). For all, intraoperative TPA, T4PA, and T9PA correlated with postoperative SVA (range, r = 0.41-0.59), whereas intraoperative PI-LL correlated less (r = 0.38). For UT (n = 49), all spinopelvic angles and LL were similar intraoperative to postoperatively (p > .09). For LT (n = 31), intraoperative and postoperative T9PA and LL were similar (p > .10) but TPA and T4PA differed (p < .02). For UT, all intraoperative and postoperative spinopelvic angles strongly correlated (r = 0.8-0.9). For LT, intraoperative to postoperative T9PA strongly correlated (r = 0.83) and TPA, T4PA, and LL correlated moderately (r = 0.65-0.70). LT trended toward more reciprocal kyphosis postoperatively (8.1° vs. 2.6°; p = .059). CONCLUSIONS:Intraoperative measurements of TPA, T4PA, and T9PA correlated better with postoperative global alignment than PI-LL, demonstrating their utility in confirming alignment goals. When comparing intraoperative to postoperative films, only T9PA was similar in LT whereas all spinopelvic angles were similar in UT. Reciprocal kyphosis in unfused segments of LT fusions may account for difference in TPA and T4PA from intraoperative to postoperative films. LEVEL OF EVIDENCE:Level III.

OBJECTIVE:Optimal patient selection for upper-thoracic (UT) versus lower-thoracic (LT) fusion during adult spinal deformity (ASD) correction is challenging. Radiographic and clinical outcomes following UT versus LT fusion remain incompletely understood. The purposes of this study were: 1) to evaluate demographic, radiographic, and surgical characteristics associated with choice of UT versus LT fusion endpoint; and 2) to evaluate differences in radiographic, clinical, and health-related quality of life (HRQOL) outcomes following UT versus LT fusion for ASD. METHODS:Retrospective review of a prospectively collected multicenter ASD database was performed. Patients with ASD who underwent fusion from the sacrum/ilium to the LT (T9-L1) or UT (T1-6) spine were compared for demographic, radiographic, and surgical characteristics. Outcomes including proximal junctional kyphosis (PJK), reoperation, rod fracture, pseudarthrosis, overall complications, 2-year change in alignment parameters, and 2-year HRQOL metrics (Lumbar Stiffness Disability Index, Scoliosis Research Society-22r questionnaire, Oswestry Disability Index) were compared after controlling for confounding factors via multivariate analysis. RESULTS:Three hundred three patients (169 LT, 134 UT) were evaluated. Independent predictors of UT fusion included greater thoracic kyphosis (odds ratio [OR] 0.97 per degree, p = 0.0098), greater coronal Cobb angle (OR 1.06 per degree, p < 0.0001), and performance of a 3-column osteotomy (3-CO; OR 2.39, p = 0.0351). While associated with longer operative times (ratio 1.13, p < 0.0001) and greater estimated blood loss (ratio 1.31, p = 0.0018), UT fusions resulted in greater sagittal vertical axis improvement (-59.5 vs -41.0 mm, p = 0.0035) and lower PJK rates (OR 0.49, p = 0.0457). No significant differences in postoperative HRQOL measures, reoperation, or overall complication rates were detected between groups (all p > 0.1). CONCLUSIONS:Greater deformity and need for 3-CO increased the likelihood of UT fusion. Despite longer operative times and greater blood loss, UT fusions resulted in better sagittal correction and lower 2-year PJK rates following surgery for ASD. While continued surveillance is necessary, this information may inform patient counseling and surgical decision-making.

Introduction/UNASSIGNED:The aim of this study was to evaluate the association of available cervical alignment components through the Ames cervical deformity (CD) classification parameters with the Patient-Reported Outcomes Measurement Information System (PROMIS) physical health domain metrics. Methods/UNASSIGNED:Surgical CD patients (C2-C7 Cobb >10° or C2-C7 sagittal vertical axis [cSVA] >4 cm or T1 slope minus cervical lordosis (TS-CL) >15°) ≥18 years with available baseline (BL) radiographic and PROMIS were isolated in a single-center spine database. Patients were classified according to the Ames CD modifiers for cSVA and TS-CL (low deformity [Low], moderate deformity [Mod], and severe deformity [Sev]). Descriptives and univariate analyses compared population-weighted PROMIS scores for Pain Intensity (PI), Physical Function (PF), and Pain Interference (Int) across CD modifiers. Conditional tree analysis with logistic regression sampling determined the threshold of PROMIS scores for which the correlation with Ames radiographic cutoffs was most significant. Reported cutoff values for Mod (cSVA: 4-8 cm; TS-CL: 15-20°) and Sev (cSVA: >8 cm; TS-CL: >20°) disabilities were used. Results/UNASSIGNED:, Charlson Comorbidity Index: 1.19). BL cSVA modifier by severity: 83.2% Low, 16.8% Mod. No patients met criteria for severe cSVA. BL TS-CL modifier by severity: 18.8% Low, 22.1% Mod, 59.1% Sev. Mean baseline PROMIS scores were as follows: PI score: 89.6 ± 15.4, PF score: 11.9 ± 13.1, Int score: 56.9 ± 6.8. PI did not differ between cSVA and TS-CL severity. Mod cSVA patients and Mod/Sev TS-CL modifier groups trended toward lower PF scores and higher Int scores. A PI score of >96 (odds ratio [OR]: 0.658 [0.303-1.430]), a PF score of <14 (OR: 1.864 [0.767-4.531]), and an Int score of > 57.4 (OR: 1.878 [0.889-3.967]) were predictors of Mod cSVA. A PI score of >87 (OR: 1.428 [0.767-2.659]), a PF score of <14 (OR: 1.551 [0.851-2.827]), and an Int score of >56.5 (OR: 1.689 [0.967-2.949]) were predictors of Sev TS-CL. Conclusions/UNASSIGNED:PROMIS physical health domains were related to the Ames CD classification. Certain BL PROMIS thresholds can be connected to the severity of CD.

Introduction/UNASSIGNED:Correction of cervical deformity (CD) often involves different types of osteotomies to address sagittal malalignment. This study assessed the relationship between osteotomy grade and vertebral level on alignment and clinical outcomes. Methods/UNASSIGNED:Retrospective review of a multi-center prospectively collected CD database. CD was defined as at least one of the following: C2-C7 Cobb >10°, cervical lordosis (CL) >10°, C2-C7 sagittal vertical axis (cSVA) >4 cm, and chin-brow vertical angle > 25°. Patients were evaluated for level and type of cervical osteotomy. Results/UNASSIGNED:= 0.058) due to lever arm effect. Conclusions/UNASSIGNED:CD patients undergoing osteotomies in the cervical and upper thoracic spine experienced improvement in TS--CL and C2 slope. In the upper thoracic spine, multiple minor osteotomies achieved similar alignment changes to major osteotomies at a single level, while a major osteotomy focused at T2 had the greatest overall impact in cervicothoracic and global alignment in CD patients.

Hypothesis/UNASSIGNED:Reciprocal changes in the upper cervical spine correlate with adult TL deformity modifiers. Design/UNASSIGNED:This was a retrospective review. Introduction/UNASSIGNED:The upper cervical spine has remarkable adaptability to wide ranges of thoracolumbar (TL) deformity. Methods/UNASSIGNED:assessed changes in BL upper cervical parameters (C0-2, C0 slope, McGregor's Slope [MGS], and CBVA) across groups. Results/UNASSIGNED:< 0.001). Conclusions/UNASSIGNED:Our study suggests that upper cervical alignment remains relatively stable through most broad variations of adult TL deformity. Changes in SVA correlated most with upper cervical changes.