Faculty Bibliography

STUDY DESIGN/METHODS:Retrospective Cohort Study. OBJECTIVE:To assess if there is a threshold of baseline disability beyond which the patient-reported outcomes after surgical correction of adult spinal deformity (ASD) are adversely impacted. BACKGROUND:Patient-reported outcomes vary after correction of adult spinal deformity, even when patients are optimally realigned. There is a paucity of literature examining the impact of baseline disability on patient-reported outcomes in ASD. METHODS:Patients with baseline (BL) and two-year data were included. Disability was ranked according to BL Oswestry Disability Index (ODI) into quintiles: Q1 (lowest ODI score) to Q5 (highest ODI score). Adjusted logistic regression analyses evaluated the likelihood of reaching ≥1 MCID in Scoliosis Research Society Outcomes Questionnaire (SRS-22) Pain, SRS-22 Activity, and Short Form-36 physical component summary at two years across disability groups Q1-Q4 with respect to Q5. Sensitivity tests were performed, excluding patients with any "0" Schwab modifiers at BL. RESULTS:Compared with patients in Q5, the odds of reaching MCID in SRS-22 Pain at 2Y were significantly higher for those in Q1 (OR: 3.771), Q2 (OR: 3.006), and Q3 (OR: 2.897), all P <0.021. Similarly, compared with patients in Q5, the odds of reaching MCID in SRS-22 Activity at two years were significantly higher for those in Q2 (OR: 3.454) and Q3 (OR: 2.801), both P <0.02. Lastly, compared with patients in Q5, odds of reaching MCID in Short Form-36 physical component summary at two years were significantly higher for patients in Q1 (OR: 5.350), Q2 (OR: 4.795), and Q3 (OR: 6.229), all P <0.004. CONCLUSIONS:This study found that patients presenting with moderate disability at BL (ODI<40) consistently surpassed health-related quality of life outcomes as compared with those presenting with greater levels of disability. We propose that a baseline ODI of 40 represents a disability threshold within which operative inte rvention maximizes patient-reported outcomes. Furthermore, delaying the intervention until patients progress to severe disability may limit the benefits of surgical correction in ASD patients. LEVEL OF EVIDENCE/METHODS:3.

OBJECTIVE:The purpose of this study was to assess how various realignment strategies affect mechanical failure and clinical outcomes in pelvic incidence (PI)-stratified cohorts following adult spinal deformity (ASD) surgery. METHODS:Median and interquartile range statistics were calculated for demographics and surgical details. Further statistical analysis was used to define subsets within PI generating significantly different rates of mechanical failure. These subsets of PI were further analyzed as subcohorts for the outcomes and effects of realignment within each subcohort. Multivariate logistic regression analysis controlling for baseline frailty and lumbar lordosis (LL; L1-S1) analyzed the association of age-adjusted realignment and Global Alignment and Proportion (GAP) strategies with the incidence of mechanical failure and clinical improvement within PI-stratified groups. RESULTS:A parabolic relationship between PI and mechanical failure was noted, whereas patients with either < 51° (n = 174, 39.1% of cohort) or > 63° (n = 114, 25.6% of cohort) of PI generated higher rates of mechanical failure (18.0% and 20.0%, respectively) and lower rates of good outcome (80.3% and 77.6%, respectively) than those with moderate PI (51°-63°). Patients with lower PI more often met good outcome criteria when undercorrected in age-adjusted PI-LL mismatch and sagittal age-adjusted score, and those not meeting good outcome criteria were more likely to deteriorate in GAP relative LL from first to final follow-up (OR 13.4, 95% CI 1.3-139.2). In those with moderate PI, patients were more likely to meet good outcome when aligned on the GAP lordosis distribution index (LDI; OR 1.7, 95% CI 0.9-3.3). Patients with higher PI meeting good outcome were more likely to be overcorrected in sagittal vertical axis (OR 2.4, 95% CI 1.1-5.2) at first follow-up and less likely to be undercorrected in T1 pelvic angle (OR 0.4, 95% CI 0.2-0.9) by final follow-up. When assessing GAP alignment, patients were more likely to meet good outcome when aligned on GAP LDI (OR 3.5, 95% CI 1.4-8.9). CONCLUSIONS:There was a parabolic relationship between PI and both mechanical failure and clinical improvement following deformity correction in this study. Understanding the associations between this fixed parameter and poor outcomes can aid the surgeon in strategical planning when seeking to realign ASD.

PURPOSE/OBJECTIVE:To assess impact of baseline disability on HRQL outcomes. METHODS:CD patients with baseline (BL) and 2 year (2Y) data included, and ranked into quartiles by baseline NDI, from lowest/best score (Q1) to highest/worst score (Q4). Means comparison tests analyzed differences between quartiles. ANCOVA and logistic regressions assessed differences in outcomes while accounting for covariates (BL deformity, comorbidities, HRQLs, surgical details and complications). RESULTS:, CCI: 0.94 ± 1.31). The cohort mean cSVA was 38.54 ± 19.43 mm and TS-CL: 37.34 ± 19.73. Mean BL NDI by quartile was: Q1: 25.04 ± 8.19, Q2: 41.61 ± 2.77, Q3: 53.31 ± 4.32, and Q4: 69.52 ± 8.35. Q2 demonstrated greatest improvement in NRS Neck at 2Y (-3.93), compared to Q3 (-1.61, p = .032) and Q4 (-1.41, p = .015). Q2 demonstrated greater improvement in NRS Back (-1.71), compared to Q4 (+ 0.84, p = .010). Q2 met MCID in NRS Neck at the highest rates (69.9%), especially compared to Q4 (30.3%), p = .039. Q2 had the greatest improvement in EQ-5D (+ 0.082), compared to Q1 (+ 0.073), Q3 (+ 0.022), and Q4 (+ 0.014), p = .034. Q2 also had the greatest mJOA improvement (+ 1.517), p = .042. CONCLUSIONS:Patients in Q2, with mean BL NDI of 42, consistently demonstrated the greatest improvement in HRQLs whereas those in Q4, (NDI 70), saw the least. BL NDI between 39 and 44 may represent a disability "Sweet Spot," within which operative intervention maximizes patient-reported outcomes. Furthermore, delaying intervention until patients are severely disabled, beyond an NDI of 61, may limit the benefits of surgery.

BACKGROUND:The aim of the current study was to compare the incidence of postoperative complications among minimally invasive surgery (MIS) tubular, endoscopic, and robot-assisted transforaminal lumbar interbody fusion (TLIF) techniques. METHODS:We studied consecutive patients who underwent single-level or multilevel TLIF between 2020 and 2022. Preoperative and postoperative patient-reported outcomes (Visual Analog Scale leg score and Oswestry Disability Index), demographic, and intraoperative variables were recorded. One-way analysis of variance with Bartlett's equal-variance and Pearson chi-squared tests were used. RESULTS:The study included 170 TLIF patients: 107 (63%) tubular, 42 (25%) endoscopic, and 21 (12%) robot assisted. All 3 TLIF techniques had similar complication rates: tubular 6 (5.6%), endoscopic 2 (4.8%), and robot assisted 1 (4.8%) all occurring within the first 2 weeks. Tubular TLIF reported the lowest incidence of new-onset neurologic symptoms, primarily radiculitis or numbness/tingling, at 2 weeks postoperatively (P < 0.05) with 21 (20%) tubular, 17 (41%) endoscopic, and 9 (43%) robot-assisted patients. There were 2 revisions in the robot-assisted group, while tubular and endoscopic each had one within 1 year. There was no statistical difference in preoperative or postoperative patient-reported outcomes between the TLIF groups. CONCLUSIONS:The current study demonstrated that tubular, endoscopic, and robot-assisted TLIF procedures had similar complication rates. The tubular MIS TLIF reported fewer new neurologic symptoms compared with endoscopic and robot-assisted TLIF procedures at 2 weeks postoperative, with all groups declining in symptom persistency at later time intervals. Average Visual Analog Scale scores continuously improved up to 1 year postoperatively among all groups.

BACKGROUND CONTEXT/BACKGROUND:Severe sagittal plane deformity with loss of L4-S1 lordosis is disabling and can be improved through various surgical techniques. However, data is limited on the differing ability of anterior lumbar interbody fusion (ALIF), pedicle subtraction osteotomy (PSO), and transforaminal lumbar interbody fusion (TLIF) to achieve alignment goals in severely malaligned patients. PURPOSE/OBJECTIVE:To examine surgical techniques aimed at restoring L4-S1 lordosis in severe adult spinal deformity (ASD). DESIGN/METHODS:Retrospective review of prospectively collected data. PATIENT SAMPLE/METHODS:A total of 96 patients who underwent ALIF, PSO, and TLIF were included in this study. OUTCOME MEASURES/METHODS:The following data were observed for all cases: patient demographics, spinopelvic parameters, complications, and PROMs. METHODS:Severe ASD patients with preoperative PI-LL >20°, L4-S1 lordosis <30°, and full body radiographs and patient-reported outcome measures (PROMs) at baseline and six-week postoperative visit were included. Patients were grouped into ALIF (1-2 level ALIF at L4-S1), PSO (L4/L5 PSO), and TLIF (1-2 level TLIF at L4-S1). Comparative analyses were performed on demographics, radiographic spinopelvic parameters, complications, and PROMs. RESULTS:Among the 96 included patients, 40 underwent ALIF, 27 underwent PSO, and 29 underwent TLIF. At baseline, cohorts had comparable age, sex, race, Edmonton frailty scores and radiographic spinopelvic parameters (p>0.05). However, PSO was performed more often in revision cases (p<0.001). Following surgery, L4-S1 lordosis correction (p=0.001) was comparable among ALIF and PSO patients and caudal lordotic apex migration (p=0.044) was highest among ALIF patients. PSO patients had higher intraoperative estimated blood loss (p<0.001) and motor deficits (p=0.049), and in-hospital ICU admission (p=0.022) and blood products given (p=0.004) but were otherwise comparable in terms of length of stay, blood transfusion given, and postoperative admission to rehab. Likewise, 90-day postoperative complication profiles and six-week PROMs were comparable as well. CONCLUSIONS:ALIF can restore L4-S1 sagittal alignment as powerfully as PSO, with fewer intra-operative and in-hospital complications. When feasible, ALIF is a suitable alternative to PSO and likely superior to TLIF for correcting L4-S1 lordosis among patients with severe sagittal malalignment.

OBJECTIVE:Recent debate has arisen between whether to use a three-column osteotomy (3CO) or multilevel low-grade (MLG) techniques to treat severe sagittal malalignment in adult spinal deformity (ASD) surgery. The goal of this study was to compare the outcomes of 3CO and MLG techniques performed in corrective surgeries for ASD. METHODS:ASD patients who had a baseline PI-LL > 30° and 2-year follow-up data were included. Patients underwent either 3CO or MLG (thoracolumbar posterior column osteotomies at ≥ 3 levels or anterior lumbar interbody fusion at ≥ 3 levels with no 3CO). The segmental utility ratio was used to assess relative segmental correction (segmental correction divided by overall correction in lordosis divided by the number of thoracolumbar interventions [interbody fusion, thoracolumbar posterior column osteotomies, and 3CO]). The paired t-test was used to assess lordotic distribution by differences in lordosis between adjacent lumbar disc spaces (e.g., L1-2 to L2-3). Multivariate analysis, controlling for age, sex, BMI, osteoporosis, baseline pelvic incidence, and T1 pelvic angle, was used to evaluate the complication rates and radiographic and patient-reported outcomes between the groups. RESULTS:A total of 93 patients were included, 53% of whom underwent MLG and 47% of whom underwent 3CO. The MLG group had a lower BMI (p < 0.05). MLG patients received fewer previous fusions than 3CO patients (31% vs 80%, p < 0.001). MLG patients had 24% less blood loss but a 22% longer operative time (565 vs 419 minutes, p = 0.008). Using adjusted analysis, the 3CO group had greater segmental and relative correction at each level (segmental utility ratio mean 69% for 3CO vs 23% for MLG, p < 0.001). However, the 3CO group had lordotic differences between two adjacent lumbar disc pairs (range -0.5° to 9.0°, p = 0.009), while MLG was more harmonious (range 2.2°-6.5°, p > 0.4). MLG patients were more likely to undergo realignment to age-adjusted standards (OR 5.6, 95% CI 1.2-46.4; p = 0.033). MLG patients were less likely to develop neurological complications or undergo reoperation (OR 0.4, 95% CI 0.1-0.9; p = 0.041). Adjusted analysis revealed that MLG patients more often met a substantial clinical benefit in the Oswestry Disability Index score (OR 5.3, 95% CI 1.1-26.8; p = 0.043). CONCLUSIONS:MLG techniques showed better utility in lumbar distribution and age-adjusted global correction while minimizing neurological complications and reoperation rates by 2 years postoperatively. In selected instances, these techniques may offer the spine deformity surgeon a safer alternative when correcting severe adult spinal deformity.

OBJECTIVE:To assess the financial impact of Enhanced Recovery After Surgery (ERAS) protocols and cost-effectiveness in cervical deformity corrective surgery. STUDY DESIGN/METHODS:Retrospective review of prospective CD database. BACKGROUND:Enhanced Recovery After Surgery (ERAS) can help accelerate patient recovery and assist hospitals in maximizing the incentives of bundled payment models while maintaining high-quality patient care. However, the economic benefit of ERAS protocols, nor the heterogeneous components that make up such protocols, has not been established. METHODS:Operative CD patients ≥18 y with complete pre-(BL) and up to 2-year(2Y) postop radiographic/HRQL data were stratified by enrollment in Standard-of-Care ERAS beginning in 2020. Differences in demographics, clinical outcomes, radiographic alignment targets, perioperative factors, and complication rates were assessed through means comparison analysis. Costs were calculated using PearlDiver database estimates from Medicare pay scales. QALY was calculated using NDI mapped to SF6D using validated methodology with a 3% discount rate to account for a residual decline in life expectancy. RESULTS:In all, 127 patients were included (59.07±11.16 y, 54% female, 29.08±6.43 kg/m 2 ) in the analysis. Of these patients, 54 (20.0%) received the ERAS protocol. Per cost analysis, ERAS+ patients reported a lower mean total 2Y cost of 35049 USD compared with ERAS- patients at 37553 ( P <0.001). Furthermore, ERAS+ patients demonstrated lower cost of reoperation by 2Y ( P <0.001). Controlling for age, surgical invasiveness, and deformity per BL TS-CL, ERAS+ patients below 70 years old were significantly more likely to achieve a cost-effective outcome by 2Y compared with their ERAS- counterparts (OR: 1.011 [1.001-1.999, P =0.048]. CONCLUSIONS:Patients undergoing ERAS protocols experience improved cost-effectiveness and reduced total cost by 2Y post-operatively. Due to the potential economic benefit of ERAS for patients incorporation of ERAS into practice for eligible patients should be considered.

STUDY DESIGN/METHODS:Retrospective cohort. OBJECTIVE:To investigate the impact of evolving Enhanced Recovery After Surgery (ERAS) protocols on outcomes after cervical deformity (CD) surgery. BACKGROUND:ERAS can help accelerate patient recovery and assist hospitals in maximizing the incentives of bundled payment models while maintaining high-quality patient care. However, there remains a paucity of literature assessing how developments have impacted outcomes after adult CD surgery. METHODS:Patients with operative CD 18 years or older with pre-baseline and 2 years (2Y) postoperative data, who underwent ERAS protocols, were stratified by increasing implantation of ERAS components: (1) early (multimodal pain program), (2) intermediate (early protocol + paraspinal blocks, early ambulation), and (3) late (early/intermediate protocols + comprehensive prehabilitation). Differences in demographics, clinical outcomes, radiographic alignment targets, perioperative factors, and complication rates were assessed through Bonferroni-adjusted means comparison analysis. RESULTS:A total of 131 patients were included (59.4 ± 11.7 y, 45% females, 28.8 ± 6.0 kg/m 2 ). Of these patients, 38.9% were considered "early," 36.6% were "intermediate," and 24.4% were "late." Perioperatively, rates of intraoperative complications were lower in the late group ( P = 0.036). Postoperatively, discharge disposition differed significantly between cohorts, with late patients more likely to be discharged to home versus early or intermediate cohorts [χ 2 (2) = 37.973, P < 0.001]. In terms of postoperative disability recovery, intermediate and late patients demonstrated incrementally improved 6 W modified Japanese Orthopedic Association scores ( P = 0.004), and late patients maintained significantly higher mean Euro-QOL 5-Dimension Questionnaire and modified Japanese Orthopedic Association scores by 1 year ( P < 0.001, P = 0.026). By 2Y, cohorts demonstrated incrementally increasing SWAL-QOL scores (all domains P < 0.028) domain scores versus early or intermediate cohorts. By 2Y, incrementally decreasing reoperation was observed in early versus intermediate versus late cohorts ( P = 0.034). CONCLUSIONS:The present study demonstrates that patients enrolled in an evolving ERAS program demonstrate incremental improvement in preoperative optimization and candidate selection, greater likelihood of discharge to home, decreased postoperative disability and dysphasia burden, and decreased likelihood of intraoperative complications and reoperation rates.

OBJECTIVE:Sagittal alignment measured on standing radiography remains a fundamental component of surgical planning for adult spinal deformity (ASD). However, the relationship between classic sagittal alignment parameters and objective metrics, such as walking time (WT) and grip strength (GS), remains unknown. The objective of this work was to determine if ASD patients with worse baseline sagittal malalignment have worse objective physical metrics and if those metrics have a stronger relationship to patient-reported outcome metrics (PROMs) than standing alignment. METHODS:The authors conducted a retrospective review of a multicenter ASD cohort. ASD patients underwent baseline testing with the timed up-and-go 6-m walk test (seconds) and for GS (pounds). Baseline PROMs were surveyed, including Oswestry Disability Index (ODI), Patient-Reported Outcomes Measurement Information System (PROMIS), Scoliosis Research Society (SRS)-22r, and Veterans RAND 12 (VR-12) scores. Standard spinopelvic measurements were obtained (sagittal vertical axis [SVA], pelvic tilt [PT], and mismatch between pelvic incidence and lumbar lordosis [PI-LL], and SRS-Schwab ASD classification). Univariate and multivariable linear regression modeling was performed to interrogate associations between objective physical metrics, sagittal parameters, and PROMs. RESULTS:In total, 494 patients were included, with mean ± SD age 61 ± 14 years, and 68% were female. Average WT was 11.2 ± 6.1 seconds and average GS was 56.6 ± 24.9 lbs. With increasing PT, PI-LL, and SVA quartiles, WT significantly increased (p < 0.05). SRS-Schwab type N patients demonstrated a significantly longer average WT (12.5 ± 6.2 seconds), and type T patients had a significantly shorter WT time (7.9 ± 2.7 seconds, p = 0.03). With increasing PT quartiles, GS significantly decreased (p < 0.05). SRS-Schwab type T patients had a significantly higher average GS (68.8 ± 27.8 lbs), and type L patients had a significantly lower average GS (51.6 ± 20.4 lbs, p = 0.03). In the frailty-adjusted multivariable linear regression analyses, WT was more strongly associated with PROMs than sagittal parameters. GS was more strongly associated with ODI and PROMIS Physical Function scores. CONCLUSIONS:The authors observed that increasing baseline sagittal malalignment is associated with slower WT, and possibly weaker GS, in ASD patients. WT has a stronger relationship to PROMs than standing alignment parameters. Objective physical metrics likely offer added value to standard spinopelvic measurements in ASD evaluation and surgical planning.