Faculty Bibliography

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.

INTRODUCTION/BACKGROUND:The sacroiliac joint (SIJ) is a potential source of pain in the ASD population. Incidence and predictors of preoperative SIJ pain and rates of resolution with surgery in the ASD population are not well understood. METHODS:A prospective, multicenter database of surgically treated ASD patients was queried for baseline SIJ pain at the preoperative assessment. SIJ pain was defined as self-reported back pain in the posterior superior iliac spine region scored ≥4 out of 10 and ≥3 of 5 positive provocative SIJ maneuvers. Demographic data, spinal alignment parameters, and health assessments were assessed using Wilcoxon and χ 2 analysis. Predictors of preoperative SIJ pain were assessed with univariate and multivariate logistic regression. RESULTS:A total of 735 patients were included with a mean (SD) age of 61.3 (15.3) years, BMI of 27.6 (5.4), Edmonton Frailty Score (EFS) of 3.4 (2.5), and Charlson Comorbidity Index (CCI) of 1.1 (1.8). A total of 65% were female and 6% were tobacco users. A total of 411 patients had self-reported PSIS pain and 53 patients (7.2%) had preoperative SIJ pain as assessed by SIJ maneuver testing. SIJ pain was not associated with history of prior lumbosacral fusion ( P =0.23). Patients with SIJ pain had higher BMI (30.0 vs . 27.4, P =0.004), preoperative pain medication usage (92.5% vs . 77.7%, P =0.02), EFS (4.6 vs . 3.3, P <0.001), and CCI (1.6 vs . 1.0, P =0.006) as well as lower L4-S1 lordosis (28.7 vs . 34.5, P =0.02) and greater L1 pelvic angle (14.5 vs . 10.8, P =0.03). After variable selection with univariate regression, multivariate logistic regression identified higher BMI (OR 1.06, P =0.033) as a significant predictor of SIJ pain at preoperative. In the patient cohort with SIJ pain at preoperative, 91.7% reported no SIJ pain at 1-year follow-up. 11/53 (20.8%) patients with baseline pain and SIJ fusion performed concurrently with ASD surgery had 100% resolution of SIJ pain in this cohort; however, there was no significant difference in pain resolution between patients with SIJ fusion and those without ( P =1). CONCLUSION/CONCLUSIONS:We found a lower prevalence of preoperative SIJ pain in ASD patients than what has been historically reported, present in 7.2% of patients. Higher BMI was a predictor of preoperative SIJ pain in this population. ASD surgery led to resolution of SIJ pain in >90% of patients at 1-year follow-up.

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: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.

STUDY DESIGN/METHODS:Retrospective cohort study of patients undergoing single-level L5-S1 anterior or transforaminal lumbar interbody fusion between 2012 and 2024 at a single academic institution, with preoperative and one-year postoperative radiographic assessment of sagittal alignment parameters. OBJECTIVE:To quantify changes in lumbar pelvic angle (LPA), pelvic tilt (PT), global lumbar lordosis (L1-S1), regional lumbar lordosis (L4-S1), and segmental lumbar lordosis (L5-S1) among single-level L5-S1 ALIF and TLIF patients. SUMMARY OF BACKGROUND DATA/BACKGROUND:Restoration of sagittal alignment is a primary goal of lumbar fusion. While ALIF is regarded as superior to TLIF in restoring segmental lordosis, its effect on global and regional alignment remains uncertain, and few studies directly compare their impact on spinopelvic parameters. METHODS:The electronic medical record was queried for patients who underwent single-level L5-S1 ALIF or TLIF with preoperative and one-year postoperative imaging. Sagittal parameters were measured using Surgimap software. Group comparisons were assessed with unpaired t-tests or Wilcoxon signed-rank tests. RESULTS:Radiographic measurements were available for 174 patients (ALIF n=73, TLIF n=101). ALIF patients had significantly greater improvement in L4-S1 (+4.2° vs. -1.1°, P=0.002) and L5-S1 lordosis (+4.6° vs. -4.8°, P<0.001). No significant differences were observed in postoperative changes for L1-S1 lordosis (+2.2° vs. -1.4°, P=0.250), LPA (-1.9° vs. -1.4°, P=0.743), or PT (-0.9° vs. +0.4°, P=0.093). Permutation testing confirmed that the observed difference in LPA improvement between cohorts (-0.51°) was not statistically significant (P=0.673), and post hoc analysis confirmed adequate power to detect a difference of 3.37°. Sensitivity analyses using ANCOVA, adjusting for baseline radiographic values and covariates, were concordant. CONCLUSION/CONCLUSIONS:ALIF provided superior regional and segmental lordosis but did not improve global alignment compared with TLIF. This study is the first to quantify the effect of ALIF versus TLIF on LPA, highlighting the limited impact of single-level fusion on global spinopelvic alignment.

STUDY DESIGN/METHODS:Retrospective review of a prospective cervical deformity (CD) database. OBJECTIVE:Determining when shorter fusions can be successful in CD surgery to reduce the extent of the surgical procedure while mitigating complications. SUMMARY OF BACKGROUND DATA/BACKGROUND:Multicenter outcomes database of CD patients. METHODS:CD patients were stratified as short fusions (SF: ≤4 levels fused, cervical LIV) or long fusions (LF: >4 levels fused, LIV caudal to C7). Groups were compared in terms of demographics, baseline and 1-year alignment, patient-reported outcome measures (PROMs), and surgical parameters. The data were then reanalyzed after controlling for baseline cervical Sagittal Vertical Axis (cSVA) using propensity score matching. Decision trees were used to identify baseline factors associated with postop alignment failure (1-year cSVA>4 mm or C2S>20°) among SF patients. RESULTS:127 patients were analyzed with 100 LF and 27 SF patients. SF had significantly less EBL (131 vs. 1001 mL) and shorter operative time (223min vs. 435 min). At baseline, LF had worse cervical alignment (cSVA=42.6 vs. 23.0 mm) and were more disabled by Neck Disability Index (NDI, 50 vs. 38). After matching by cSVA, the mean baseline cSVA decreased from 42.6 mm to 27.6 mm in the LF group and increased from 23.0 mm to 27.2 mm in the SF group. 71% (n=15) of SF achieved the MCID for NDI vs. 52% (n=11) of LF pts. SF patients with a BL C2S>26° (n=13) were 12.4 times as likely as SF patients with C2S≤26° (n=13) to have post-operative alignment failure (85% vs. 31%, P<.01) and 5.1 times as likely to have a post-operative complication (69% vs. 31%, P<.05). CONCLUSIONS:Although short fusions can result in excellent outcomes with less extensive surgeries, those with more severe deformities may require longer fusions. SF should be avoided in patients with a BL C2S>26° due to the increased risk of complications and realignment failure.

OBJECTIVE:The aim of this study was to determine predictors of the minimum clinically important difference (MCID) in the Neck Disability Index (NDI) following cervical spinal deformity surgery. METHODS:A retrospective review was performed of a prospective, multicenter adult cervical spinal deformity database. All patients had baseline and 1-year NDI scores. Patients met MCID with an improvement of NDI by 7 points between baseline and 1 year, as previously established. Baseline demographics, comorbidities, and both baseline and 1-year spinopelvic parameters were evaluated for statistical significance in a univariate logistic regression analysis. Significant variables, in addition to baseline NDI, were analyzed in a multivariable logistic regression model by backward selection with Akaike information criterion minimization. RESULTS:A total of 122 patients were included with a median age of 62 (IQR 56, 69) years; 62% of patients were female. Of the 122 patients, 72 (59%) achieved NDI MCID at 1 year. Predictors of achieving MCID on univariate analysis included a lower Charlson Comorbidity Index (CCI) total score (OR 0.70, p = 0.03), depression as a comorbidity (OR 2.9, p = 0.02), lower C2 tilt at the 1-year follow-up (OR 0.92, p = 0.02), and a greater difference between 1-year postoperative C2-7 sagittal vertical axis (SVA) and preoperative C2-7 SVA (OR 0.98, p = 0.0495). On multivariable logistic regression analysis, predictors of achieving MCID included a lower CCI (OR 0.62, p = 0.03), depression as a comorbidity (OR 3.1, p = 0.059), a greater change in C2-7 SVA at the 1-year follow-up compared with baseline (OR 0.97, p = 0.055), and baseline NDI (OR 1.02, p = 0.24) with an area under the curve of 0.74. CONCLUSIONS:The best-fit multivariable model included higher baseline NDI, a greater change in C2-7 SVA, patient-reported baseline depression, and lower CCI as important factors in predicting NDI MCID.

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.

PURPOSE/OBJECTIVE:To compare the impact of lumbar lordosis correction achieved by cephalad versus caudal distribution on radiographic alignment and surgical outcomes among adult spinal deformity (ASD) patients. METHODS:Patients who underwent ASD surgery with uppermost instrumented vertebrae (UIV) at or above L1, had preoperative pelvic incidence-lumbar lordosis (PI-LL) > 10°, and had full-body radiographs available were included. Eligible patients were categorized by the focus of lordosis correction: caudal (L4-S1 lordosis between 35 and 45°) and cephalad lordosis-based correction. Patient demographics, preoperative and 2 years spinopelvic alignment and PROMs, and 2 years postoperative surgical complications were compared. RESULTS:In total, 187 (111 caudal and 76 cephalad) patients were included, with mean age of 66.2 years, 78.6% female, and mean frailty score of 3.6. Caudally-restored patients often had an upper thoracic UIV, sacrum/ilium LIV, longer length of fusion, and no lateral lumbar interbody fusion (LLIF) while cephaladly-restored patients had two or more LLIFs above L4 (p < 0.001). Preoperatively, there were no significant differences in radiographic alignment and PROMs between the two groups (p > 0.02). Two years postoperatively, caudally-restored patients had higher L1-S1 LL (p = 0.015) and L4-S1 LL (p < 0.001), and lower PI-LL (p = 0.039) and SVA (p = 0.001). In addition, they had higher SRS-22 activity (p = 0.045), pain (p = 0.047), appearance (p = 0.046), and total (p = 0.016) scores. Finally, they had lower rates of sensory deficits (p < 0.001), motor deficits (p = 0.003), implant failure (p = 0.092), and reoperation (p = 0.020). CONCLUSION/CONCLUSIONS:Caudal lordosis-based correction of spinal deformity patients was associated with higher PROMs and lower rates of neurologic deficits, implant failure, and revisions at 2 years. These findings, while subject to unmeasured confounding, indicate that great caution should be taken when considering cephalad-based correction of ASD.