Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective cohort analysis. OBJECTIVE:Assess the distribution of Medicare's spinal-deformity-specific diagnosis-related group (DRGs) relative to surgical invasiveness, hospital length of stay (LOS), discharge disposition, 90-day postoperative quality metrics, and reimbursement costs for adult spinal deformity (ASD) operations. SUMMARY OF BACKGROUND DATA/BACKGROUND:Heterogeneity of ASD call into question Medicare's DRGs to accurately capture nuances of ASD surgical episodes of care. METHODS:Adults who underwent thoracic to pelvis instrumentation with associated DRGs were identified from a multicenter database. Demographics, operative details, inpatient course, discharge disposition, 90-day adverse events, and reimbursement costs were compared between spinal deformity-specific DRG codes. Distribution of DRGs for a subset of these patients who fit into one of 6 commonly performed surgical strategies to address ASD was also assessed. RESULTS:Of the 314 patients included for analysis, the majority fell into +CC DRGs, while the minority had +MCC DRGs or no MCC/CC DRG. Within each DRG, there was considerable heterogeneity in regard to patients' ages, ASA, CCI, frailty, surgical invasiveness, postoperative ICU/hospital LOS, discharge disposition, and complication profiles.+MCC DRGs had significantly greater ASA and Edmonton Frailty Scores. While +MCC and +CC had relatively similar surgical invasiveness, +MCC had greater ICU admissions, in-hospital adverse events, and nonhome discharges as well as longer ICU, hospital, and rehab LOS. While reimbursements were significantly higher for +MCC DRG compared with +CC DRGs and DRGs without MCC/CC, there were large ranges in reimbursement within all DRG subgroups.The 7 DRGs varied significantly within and between the subset of 6 commonly performed surgical strategies, although there were no differences in regard to ICU admissions and LOS, hospital LOS, discharge disposition, and number of adverse events (in-hospital, 90-day). CONCLUSIONS:While Medicare's spinal-deformity DRG codes capture average trends in surgical/postoperative episodes of care for ASD patients, each encompasses highly heterogeneous patients and associated surgical operations rendering them unreliable gauges of patient/surgical complexity, early postoperative trajectories, and reimbursement costs. A more granular system is needed to more accurately capture the nuances of ASD operations and their associated quality metrics and reimbursement costs.

STUDY DESIGN/METHODS:Retrospective review of a prospective, multicenter adult cervical deformity (CD) database. OBJECTIVE:Investigate the prevalence and clinical significance of combined cervical scoliosis (CS) and cervical kyphosis (CK) among patients undergoing surgical management of CD. SUMMARY OF BACKGROUND DATA/BACKGROUND:Although adult CD patients may have both CS and CK, few studies have confirmed prevalence of CK and CS and associated radiographic and clinical findings. MATERIALS AND METHODS/METHODS:Patients undergoing surgery for CD [defined as C2-C7 ≥10° kyphosis, cervical sagittal vertical axis (SVA) >4 cm, or C2-C7 coronal Cobb angle ≥10°] were included. CS was defined as C2-C7 coronal Cobb angle ≥10°. RESULTS:Totally, 114 patients were included (mean age 62.5 yr, 51.8% female). Fourteen patients (12.3%) had combined CS and CK, and 100 patients (87.7%) had CK alone. Preoperative maximum cervical coronal Cobb angle was 3.9° in the CK alone group and 14.6° in the combined CS and CK group. In the combined CS and CK group, this value improved to 8.1° postoperatively ( P =0.0007 vs. preoperative), but CS ≥10° was still present in three patients, with a mean correction percentage of only 48.0% of initial CS.No significant differences were observed between the CK only and combined CS and CK groups with regard to baseline sagittal parameters, change between immediate postoperative and baseline sagittal parameters, surgical approach, age, or baseline HRQOL. Patients with combined CS and CK were more frequently female than patients with CK alone (85.7% vs. 41.2%, P =0.0066). CONCLUSIONS:The vast majority of patients presented with CK alone (88%), and only 12% of adult CD patients had combined CS and CK. Because of the significant residual coronal plane deformity-∼50%-surgical correction should be focused on both coronal and sagittal plane deformity in the combined CS and CK group.

STUDY DESIGN/METHODS:Retrospective Multi-Center Study. OBJECTIVE:To investigate how advances in spine realignment have impacted lumbar segmental alignment. SUMMARY OF BACKGROUND DATA/BACKGROUND:The understanding of spine alignment and Adult Spinal Deformity (ASD) management continues to advance. It remains unknown how these advances have influenced lumbar segmental alignment changes in the setting of surgical correction. METHODS:Patients undergoing primary thoracolumbar fusion for ASD were stratified based on enrolment in two distinct multicenter registries; forming an 'Early' (2008-2017) and a 'Late cohort' (2018-present). Patients were further stratified based on pelvic incidence (PI) and Roussouly type. Segmental alignment was determined based on published values of asymptomatic individuals. Pelvic incidence-based alignment and Roussouly-based alignment were determined in alignment with previously published normative values. Means comparisons tests and multivariate analyses compared segmental & regional parameters between groups. RESULTS:1240 patients included (622 EARLY, 618 LATE). The mean age was 61.4±14.5 years, body mass index (BMI) was 28.0±5.8 kg/m2, and Charlson comorbidity index (CCI) was 1.55±1.70. 70.2% of patients were female gender. LATE consistently displayed better L5-S1 alignment across all PI and Roussouly types (P=0.001) However, EARLY demonstrated better L4-5 alignment (P=0.001). Improved alignment in L5-S1, L4-5 and L3-4 was associated with achieving minimum clinically important difference in ODI scores and decreased risk of mechanical complications. Both cohorts demonstrated low rates of matching L4-S1 regional and overall lumbar lordosis L1-S1 alignment, with no differences between both groups. By lordosis distribution index, both groups had predominantly hyperlordotic maldistribution postop, but LATE had more 'Aligned' patients (15.9 vs. 11%, P<0.001). CONCLUSIONS:Over the past 15 years, surgeons appear to be better at restoring ideal lumbar segmental sagittal alignment in ASD patients. However, idealized correction does not appear to be uniform across all lumbar segments, representing an opportunity for further improvement. LEVEL OF EVIDENCE/METHODS:III.

STUDY DESIGN/METHODS:Retrospective cohort study using a multicenter, prospectively collected adult spinal deformity (ASD) database. OBJECTIVE:To determine whether achieving the ideal L1 pelvic angle (L1PA) in minimally invasive surgery (MIS) for ASD correction is associated with reduced mechanical failure and improved clinical outcomes. SUMMARY OF BACKGROUND DATA/BACKGROUND:Prior research has shown that achieving ideal L1PA-defined as (0.5×pelvic incidence)-21-is linked to lower reoperation risk in open ASD correction. Its relevance in MIS has not been well established. METHODS:A total of 1104 ASD patients across 13 centers were included (criteria: scoliosis ≥20°, SVA ≥5 cm, PT ≥25°, or TK ≥60°, with ≥2-year follow-up). Radiographic parameters and patient-reported outcomes (PROs) were collected preoperatively, at six weeks, and at final follow-up. Ideal L1PA was defined as within ±5° of the calculated target. MIS was defined as circumferential MIS (LLIF/ALIF with percutaneous posterior fixation). Associations between alignment and outcomes (reoperation, PROs) were analyzed using linear regression and t tests. RESULTS:Ideal L1PA was achieved in 63% of MIS cases and 61% of open cases ( P =0.342). Among MIS patients, ideal L1PA correlated with lower reoperation rates (15% vs. 33%, P <0.01) and greater improvement in SRS-22 total (Δ0.85 vs. Δ0.40, P <0.01) and SF-36 PCS scores (Δ9.1 vs. Δ4.6, P =0.04). In contrast, ideal L1PA was not associated with reduced reoperation in the open group. Across all patients, each 1° deviation from ideal L1PA increased reoperation risk by 1.8% ( P =0.04). CONCLUSIONS:Ideal L1PA is achievable in MIS at similar rates as open surgery. In MIS-treated ASD patients, achieving ideal alignment is associated with reduced reoperation and improved clinical outcomes, supporting its role as a key surgical target.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:Due to proximity of the surgical site to important respiratory structures, patients may undergo delayed extubation after adult cervical deformity (ACD) surgery to manage postoperative airway edema/obstruction. Herein, we evaluate relevant relationships with delayed extubation. SUMMARY OF BACKGROUND DATA/BACKGROUND:Delayed extubation is an underreported perioperative occurrence, with only a few studies conducting case-by-case reviews of prolonged intubation. METHODS:Operative ACD patients with baseline (BL) were grouped based on whether they experienced delayed extubation (DE), or leaving the OR while still intubated, versus those who were extubated successfully in the OR (non-DE). Means comparison and regression analyses identified predictors of delayed extubation and associations with peri-operative complications and outcomes. RESULTS:82 patients met inclusion criteria (mean age 62.4±13.0 y, 52.4% female, Edmonton frailty score: 5.10±2.97, ACFI score: 0.30±0.16, CCI: 1.41±1.73). 14 patients left the OR intubated, and 1(1.2%) required reintubation. DE cohort demonstrated greater Edmonton frailty scores (P=0.017) and smoking histories (P=0.031). Intraoperatively, there was a significant difference EBL (P=0.021) and rate of transfusions (DE: 27.3% v non-DE: 4.8%, P=0.12). Upper instrumented vertebra (UIV) was not associated with DE, while lower LIV increased the likelihood of DE (OR 1.1, P=0.029). Post-operatively, as expected, there was a significant difference in rate of SICU admissions (DE: 90.9% v. non-DE: 49.2%, P=0.01), although no significant differences in LOS. Greater cSVA and MGS correction from baseline was associated with increased likelihood of delayed extubation (OR 1.1, CI 95% 1.05-1.17, P<.001; OR 1.14, CI 95% 1.05-1.24, P=0.003). Furthermore, delayed extubation was a significant predictor of increased VR-Physical Component Scores (P=0.013) at 6W, and DE cohort demonstrated significantly higher VR-PCS and VR-MCS Scores at 6W (P=0.01, both). CONCLUSIONS:Baseline frailty and larger radiographic correction can be associated with delayed extubation, which can impact quality of life perioperatively. Considerations like minimizing intraoperative blood loss and degree of correction could minimize delayed extubation.

STUDY DESIGN/METHODS:Prospective, multi-center analysis. OBJECTIVE:Evaluate the impact that self-image has upon operative vs. nonoperative treatment choice for adult spine deformity (ASD) patients, and evaluate the association of post-treatment self-image with treatment satisfaction. SUMMARY OF BACKGROUND DATA/BACKGROUND:ASD outcomes traditionally focus upon pain and physical function. Self-image is an important outcome measure for pediatric spine deformity. Little data exists regarding the impact self-image has upon ASD treatment choice and outcomes. METHODS:Factor analysis and decision tree modeling was performed upon ASD patients prospectively enrolled into a multi-center study from 2009-2020. Data elements from physical examination, demographics, spinal alignment, and individual questions from administered PROMs including SRS-22r, ODI, SF-36, and NRS back and leg pain were evaluated for variables that correlated most with (1) patients electing for operative vs. nonoperative treatment and (2) treatment satisfaction at minimum 2-year follow-up. RESULTS:Evaluation of 735 ASD patients demonstrated operatively treated patients (OP; n=548) were older (58.0±15.3 vs. 52.4±16.0 years; P<0.0001), had similar scoliosis (44.9±20.1° vs. 45.5±16.1°; P=0.5555) but worse sagittal malalignment than nonoperatively treated patients (NON; n=187; P<0.0001, respectively). Baseline PROMs were worse for OP vs. NON (P<0.0001). Gradient-boosted decision trees, factor analysis, and logistic regression of demographic, physical examination, radiographic, and PROM variables associated with treatment choice demonstrated self-image (odds ratio=4.5; 95% CI=3.4-6.0; P<0.0001) had the greatest correlation for patients choosing operative treatment. At minimum 2-year follow-up self-image demonstrated the greatest health domain improvement for OP and self-image improvement correlated most with post-treatment satisfaction, while NON demonstrated deterioration of self-image and reported poor treatment satisfaction. CONCLUSION/CONCLUSIONS:Multi-variable evaluation of 735 operative and nonoperative treated ASD patients demonstrated baseline self-image strongly correlated with ASD patients pursuing surgical treatment and postoperative treatment satisfaction. Patient self-image is a critical measure that must be assessed in ASD.

Adult spinal deformity patients undergoing total hip arthroplasty experience higher hip dislocation rates than those with normal spinal alignment. The traditional Lewinnek safe zone does not account for spinopelvic variation such as pelvic retroversion. To address this, three patient-specific normative zones for acetabular anteversion were defined. A multicenter retrospective analysis of 146 adult spinal deformity patients and 47 asymptomatic controls was performed using three-dimensional biplanar radiograph reconstructions to measure spinopelvic alignment and acetabular orientation. Normative Zone 1, for patients not undergoing spinal realignment, was delineated by the 95% confidence interval limits: minimum anteversion = 0.3182 × pelvic tilt +2.947 and maximum anteversion = 0.3317 × pelvic tilt +25.823. Normative Zone 2, for patients following spinal realignment, was based on pelvic incidence: minimum anteversion = 0.0682 × pelvic incidence +9.7749 and maximum anteversion = 0.0698 × pelvic incidence +21.5218. Normative Zone 3, intended for cases with uncertain spinal correction plans, was defined as the intersection of Zones 1 and 2, yielding a narrower target anteversion range. These zones enable patient-specific cup placement that accounts for existing or planned spinal alignment, with the potential to reduce dislocation risk. Clinical Significance: This study provides acetabular cup orientation tailored to each patient's spinopelvic alignment and surgical plan, potentially reducing dislocation rates in spinal malalignment patients.

STUDY DESIGN/METHODS:Multicenter prospective study. OBJECTIVE:The present study investigates in-construct measurements of sagittal angles (SA) within the fusion from C2 to various thoracic vertebrae, which can be used as targets for CD correction. SUMMARY OF BACKGROUND DATA/BACKGROUND:Correcting cervical deformity (CD) has the potential to significantly improve patient function. However, previously described radiographic parameters cannot be measured intraoperatively. METHODS:Patients with CD that had a LIV at T1 or caudal were included. Patients were categorized into the failed outcome group if they had a cSVA of more than 4 cm within 3 months postoperatively. The in-construct measurements were based on patients' LIV. All patients had a C2-T1 SA. C2-T4 SA were compared between groups with LIV below T4, and C2-T10 SA between groups with LIV below T10. Change in C2-LIV SA described the correction within the fusion for each patient. Linear regression analysis was used to determine the C2-T1, C2-T4, C2-T10 SA measures corresponding to a cSVA = 4 cm.HRQL analysis was done in patients with 1-year follow-up. RESULTS:Among 143 patients (mean age 63, 60% female), 51% had radiographic failure. Multivariate regression showed that postoperative C2-T1 SA independently predicted failed alignment (OR = 1.22, CI 1.10-1.35; P < 0.001). A cSVA of 4 cm correlated with a C2-T1 SA of -9.6° and C2-T10 SA of 14.7° (r > 0.38, P < 0.05). ΔDJKA was found to significantly correlated with the C2-T10 SA (r > 0.57, P = 0.02). Though HRQL outcomes did not differ significantly between groups, greater C2-LIV SA correction was associated with improved neck pain (r > 0.42, P = 0.036). CONCLUSION/CONCLUSIONS:Failure to restore cSVA and development of DJK was independently associated with under correction as evidenced by significantly larger postoperative in-construct angles.

BACKGROUND/UNASSIGNED:The increasing prevalence of adult spinal deformity (ASD) highlights the need for effective treatment strategies. While minimally invasive spine surgery has improved outcomes, patients with severe deformity often require more extensive correction. This study evaluates the outcomes of combining prone transpsoas (PTP) lumbar interbody fusion with posterior column osteotomies (PCO) or pedicle subtraction osteotomies (PSO) for severe ASD correction. METHODS/UNASSIGNED:-tests, and Spearman's rank coefficients were used to evaluate correlations. RESULTS/UNASSIGNED:Complication rates were similar between PCO and PSO patients. Significant improvements were observed in lumbar lordosis (LL) (P=0.002), SVA (P=0.03), TPA (P=0.04), coronal Cobb angle (P=0.03), and PI-LL mismatch (P=0.003). SL did not change significantly at any level. Clinically, ODI, VAS-B, and VAS-L scores improved significantly (P<0.001 for all). Correlations showed moderate to strong negative associations between SL at L2-L3 and patient-reported outcomes. CONCLUSIONS/UNASSIGNED:Combining PTP with PCO or PSO provides significant radiographic and clinical improvements in severe ASD patients. This hybrid approach may serve as a safe, efficient alternative to traditional multistage open surgeries, warranting further prospective validation.

OBJECTIVE:The objective of this study was to determine whether increased cell saver (CS) salvage transfusion to estimated blood loss (EBL) ratio (CS:EBL) is a driver in the development of cardiopulmonary (CP) and/or renal complications. METHODS:Patients with adult spinal deformity (ASD) enrolled in a multicenter, observational prospective study from 13 spinal deformity centers in North America were queried. Eligible participants met at least one of the following radiographic and/or procedural inclusion criteria: pelvic incidence-lumbar lordosis mismatch ≥ 25°, T1 pelvic angle ≥ 30°, sagittal vertical axis ≥ 15 cm, thoracic scoliosis ≥ 70°, thoracolumbar/lumbar scoliosis ≥ 50°, global coronal malalignment ≥ 7 cm, having undergone a 3-column osteotomy, spinal fusion ≥ 12 levels, and/or age ≥ 65 years with ≥ 7 levels of instrumentation. Patients were dichotomized based on whether their CS:EBL was ≥ or < 0.33. Patients who did not have CS transfused intraoperatively were excluded. Key outcomes included renal and CP-related medical complications. Patient characteristics, preoperative laboratory results, operative data, and radiographic parameters were compared using appropriate statistical tests. A conceptual multivariable logistic regression model was built to assess risk factors associated with the primary outcome. RESULTS:Four hundred six patients were included in this analysis, including 10.6% (n = 43) with a CS:EBL ≥ 0.33 and 89.4% (n = 363) with a CS:EBL < 0.33. The patients with a CS:EBL ≥ 0.33 were significantly older (mean 66.2 [SD 12.2] vs 58.9 [SD 16.4] years, p = 0.0007), experienced less EBL intraoperatively (mean 1048.3 [SD 852.2] vs 1695.6 [SD 1295.3] ml, p < 0.0001), had fewer total instrumented levels (mean 12.2 [SD 3.3] vs 14.1 [SD 3.6] levels, p = 0.0001), had fewer posterior column osteotomies performed (72.1% vs 86.8%, p = 0.0103), and had less major coronal Cobb angle correction (mean -17.0° [SD 14.6°] vs -22.7° [SD 16.7°], p = 0.0373). Despite comparable transfusion rates, patients with a CS:EBL ≥ 0.33 had fewer packed red blood cell (RBC), fresh frozen plasma, and platelet units transfused intraoperatively (p < 0.05). No significant differences were observed among overall CP and renal complications. However, when stratifying CP complications by type, patients with a CS:EBL ≥ 0.33 experienced a significantly greater rate of pulmonary embolisms (PEs; 9.3% vs 1.4%, p = 0.0093) within 30 days of surgery. A multivariable logistic regression model adjusted for the significant differences between the two groups found a CS:EBL ≥ 0.33 to be an independent risk factor for the development of a PE, conferring an odds ratio of 6.57 (95% CI 1.75-24.66) with excellent model diagnostics (model p value = 0.0031, area under the receiver operating characteristic curve = 0.92). CONCLUSIONS:Patients with a high CS:EBL were at a significantly greater risk of developing a PE within the early postoperative period independent of blood loss and operative complexity. The findings support the re-evaluation of salvaged RBC use in this patient population based on perceived benefits.