Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective review of multicenter data. OBJECTIVE:To compare long-term neurologic recovery in patients with and without incidental durotomy (hereafter, "durotomy") after adult spinal deformity surgery. SUMMARY OF BACKGROUND DATA/BACKGROUND:Durotomy is a common complication of adult spinal deformity surgery and is typically associated with technical challenges during the procedure. METHODS:Using a prospectively collected database, we included 1452 patients (73% female; mean age, 60±14 y) who underwent adult spinal deformity surgery from 2008-2020 at 22 US centers. We compared patients with and without durotomy with respect to demographic characteristics, surgical variables, and neurologic outcomes at baseline and at 1 and 2 years postoperatively. Multivariate analysis compared neurologic complications and length of stay (LOS) between the groups. P<.05 was considered significant. RESULTS:Durotomy occurred in 121 patients (8.3%). Patients with durotomy were more likely to have undergone revision surgery (P<.001) and had higher Charlson Comorbidity Index values (P=.029) than those who did not. Patients with durotomy had higher estimated blood loss, longer operative time, more frequent 3-column osteotomies, and longer LOS (all, P<.001). Lower-extremity motor scores did not differ between patients with durotomy and those without at 1 and 2 years postoperatively. The incidence of neurologic, medical, and surgical complications did not differ significantly between the 2 groups. Patients with durotomy had a higher rate of inpatient return to the operating room (5.0%) than those without (2.0%) (P=.04). On multivariate analysis, there were no differences between groups in lower-extremity motor scores, neurologic complications, or LOS. CONCLUSIONS:Incidental durotomy during adult spinal deformity surgery was associated with greater intraoperative complexity and transient sensory symptoms but did not adversely affect long-term motor recovery, neurologic complications, or patient-reported outcomes. These findings suggest durotomy is a manageable complication without lasting functional consequences.

STUDY DESIGN/METHODS:Retrospective review of prospectively collected, multicenter data. OBJECTIVE:To assess associations between patient height and weight independently and interactively with the incidence of proximal junctional kyphosis (PJK) after surgical treatment of adult spine deformity. SUMMARY OF BACKGROUND DATA/BACKGROUND:Body mass index has traditionally been used to assess the influence of body composition on surgical outcomes, but the individual effects of height and weight have not been studied in relation to PJK. METHODS:We compared baseline demographic characteristics, radiographic measurements, and perioperative variables between patients who developed PJK after adult spinal deformity surgery between 2008 and 2020 and those who did not. Using a generalized additive model with a logistic link function, we modeled height and weight and their interaction as smooth terms to capture potential nonlinear effects on PJK risk. Multivariate analysis was adjusted for age, history of osteoporosis, upper instrumented vertebra, number of levels fused, and postoperative pelvic incidence minus lumbar lordosis and T1 pelvic angle. RESULTS:Of 904 included patients, the median age was 65 years (interquartile range: 58-71), and 76% were female. PJK developed in 131 patients (14%). Baseline characteristics, including frailty, comorbidities, and radiographic measures, did not differ significantly between the PJK and non-PJK groups. Taller height was a predictor of PJK (P=.03). In contrast, weight was not an independent predictor, and there was no significant interaction between height and weight. The incidence of PJK peaked at a height of approximately 179 cm before plateauing. CONCLUSIONS:Taller height, but not weight, was associated with developing PJK after adult spinal deformity surgery. These findings underscore the importance of considering patient height during surgical planning.

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 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: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.

STUDY DESIGN/METHODS:Retrospective cohort study. OBJECTIVE:To examine the degree of overlap between disability, multimorbidity, and frailty in a cohort of ASD patients. SUMMARY OF BACKGROUND DATA/BACKGROUND:Frailty is a popular topic in spine research, as it is a reported risk factor for poor outcomes. Disability, multimorbidity, and frailty can coexist, sometimes causing or exacerbating one another. It is important to distinguish these conditions for perioperative optimization and to guide research initiatives. METHODS:A multicenter registry of ASD patients was queried for baseline data regarding frailty, as measured by the Edmonton Frail Scale, disability, as measured by the Oswestry Disability Index, and multimorbidity, as measured by the Charlson Comorbidity Index. The relationships between these measures and both chronological and biological age (PhenoAge) were explored. Exploratory factor analysis (EFA) examined areas of overlap between these diagnoses. RESULTS:There were 861 patients contributing data, mostly female (68%), most undergoing primary surgery at a median age of 66 years (Interquartile Range (55.1-71.6), with 6% classified as "Frail." Chronological and PhenoAge showed weak to moderate associations with disability and frailty, though PhenoAge was stronger. There was no evidence of distinct clusters, rather a continuity of condition severity. EFA found overlap between subjective and objective measures of disability, function, and frailty. CONCLUSIONS:Frailty was rare (6%) in this multicenter cohort of patients. Conflation of disability and frailty is a real risk due to overlap in measures of both conditions. Disability and frailty do not form discrete categories but rather exist along a continuum, underscoring the need to abandon categorical labels in favor of continuous measures for both clinical assessment and research settings.

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 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: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.