Factors Influencing Maintenance of Alignment and Functional Improvement Following Adult Spinal Deformity Surgery: A 3-Year Outcome Analysis.

STUDY DESIGN: This was a retrospective review. OBJECTIVE: To assess the factors contributing to durability of surgical results following adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND: Factors contributing to the long-term sustainability of ASD correction are currently undefined. MATERIALS AND METHODS: Operative ASD patients with preoperatively (baseline) and 3-year postoperatively radiographic/health-related quality of life data were included. At 1 and 3 years postoperatively, a favorable outcome was defined as meeting at least three of four criteria: (1) no proximal junctional failure or mechanical failure with reoperation, (2) best clinical outcome (BCO) for Scoliosis Research Society (SRS) (≥4.5) or Oswestry Disability Index (ODI) (<15), (3) improving in at least one SRS-Schwab modifier, and (4) not worsening in any SRS-Schwab modifier. A robust surgical result was defined as having a favorable outcome at both 1 and 3 years. Predictors of robust outcomes were identified using multivariable regression analysis with conditional inference tree for continuous variables. RESULTS: We included 157 ASD patients in this analysis. At 1 year postoperatively, 62 patients (39.5%) met the BCO definition for ODI and 33 (21.0%) met the BCO for SRS. At 3 years, 58 patients (36.9%) had BCO for ODI and 29 (18.5%) for SRS. Ninety-five patients (60.5%) were identified as having a favorable outcome at 1 year postoperatively. At 3 years, 85 patients (54.1%) had a favorable outcome. Seventy-eight patients (49.7%) met criteria for a durable surgical result. Multivariable adjusted analysis identified the following independent predictors of surgical durability: surgical invasiveness >65, being fused to S1/pelvis, baseline to 6-week pelvic incidence and lumbar lordosis difference >13.9°, and having a proportional Global Alignment and Proportion score at 6 weeks. CONCLUSIONS: Nearly 50% of the ASD cohort demonstrated good surgical durability, with favorable radiographic alignment and functional status maintained up to 3 years. Surgical durability was more likely in patients whose reconstruction was fused to the pelvis and addressed lumbopelvic mismatch with adequate surgical invasiveness to achieve full alignment correction.

Cost Benefit of Implementation of Risk Stratification Models for Adult Spinal Deformity Surgery.

STUDY DESIGN/SETTING: Retrospective cohort study. OBJECTIVE: Assess the extent to which defined risk factors of adverse events are drivers of cost-utility in spinal deformity (ASD) surgery. METHODS: ASD patients with 2-year (2Y) data were included. Tertiles were used to define high degrees of frailty, sagittal deformity, blood loss, and surgical time. Cost was calculated using the Pearl Diver registry and cost-utility at 2Y was compared between cohorts based on the number of risk factors present. Statistically significant differences in cost-utility by number of baseline risk factors were determined using ANOVA, followed by a generalized linear model, adjusting for clinical site and surgeon, to assess the effects of increasing risk score on overall cost-utility. RESULTS: By 2 years, 31% experienced a major complication and 23% underwent reoperation. Patients with ≤2 risk factors had significantly less major complications. Patients with 2 risk factors improved the most from baseline to 2Y in ODI. Average cost increased by $8234 per risk factor (R2 = .981). Cost-per-QALY at 2Y increased by $122,650 per risk factor (R2 = .794). Adjusted generalized linear model demonstrated a significant trend between increasing risk score and increasing cost-utility (r2 = .408, P < .001). CONCLUSIONS: The number of defined patient-specific and surgical risk factors, especially those with greater than two, were associated with increased index surgical costs and diminished cost-utility. Efforts to optimize patient physiology and minimize surgical risk would likely reduce healthcare expenditures and improve the overall cost-utility profile for ASD interventions.Level of evidence: III.

External Validation of the National Surgical Quality Improvement Program Calculator Utilizing a Single Institutional Experience for Adult Spinal Deformity Corrective Surgery.

BACKGROUND: Identify the external applicability of the American College of Surgeons' National Surgical Quality Improvement Program (NSQIP) risk calculator in the setting of adult spinal deformity (ASD) and subsets of patients based on deformity and frailty status. METHODS: ASD patients were isolated in our single-center database and analyzed for the shared predictive variables displayed in the NSQIP calculator. Patients were stratified by frailty (not frail <0.03, frail 0.3-0.5, severely frail >0.5), deformity [T1 pelvic angle (TPA) > 30, pelvic incidence minus lumbar lordosis (PI-LL) > 20], and reoperation status. Brier scores were calculated for each variable to validate the calculator's predictability in a single center's database (Quality). External validity of the calculator in our ASD patients was assessed via Hosmer-Lemeshow test, which identified whether the differences between observed and expected proportions are significant. RESULTS: A total of 1606 ASD patients were isolated from the Quality database (48.7 years, 63.8% women, 25.8 kg/m2); 33.4% received decompressions, and 100% received a fusion. For each subset of ASD patients, the calculator predicted lower outcome rates than what was identified in the Quality database. The calculator showed poor predictability for frail, deformed, and reoperation patients for the category "any complication" because they had Brier scores closer to 1. External validity of the calculator in each stratified patient group identified that the calculator was not valid, displaying P values >0.05. CONCLUSION: The NSQIP calculator was not a valid calculator in our single institutional database. It is unable to comment on surgical complications such as return to operating room, surgical site infection, urinary tract infection, and cardiac complications that are typically associated with poor patient outcomes. Physicians should not base their surgical plan solely on the NSQIP calculator but should consider multiple preoperative risk assessment tools.

Trends in Outcomes of a Prospective Consecutively Enrolled Single-Center Adult Cervical Deformity Series.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: The aim was to describe the two-year outcomes for patients undergoing surgical correction of cervical deformity (CD). BACKGROUND: Adult CD has been shown to compromise health-related quality of life. While advances in spinal realignment have shown promising short-term clinical results in this parameter, the long-term outcomes of CD corrective surgery remain unclear. MATERIALS AND METHODS: Operative CD patients >18 years with two-year (2Y) health-related quality of life/radiographic data were included. Improvement in radiographic, neurologic, and health-related quality of life outcomes were reported. Patients with a prior cervical fusion and patients with the greatest and smallest change based on Neck Disability Index (NDI), numeric rating scale (NRS) neck, modified Japanese Orthopaedic Association (mJOA) were compared using multivariable analysis controlling for age, and frailty, and invasiveness. RESULTS: One hundred and fifty-eight patients were included in this study. By 2Y, 96.3% of patients improved in Ames cervical sagittal vertical axis modifier, 34.2% in T1 slope minus cervical lordosis (TS-CL), 42.0% in horizontal gaze modifier, and 40.9% in SVA modifier. In addition, 65.5% of patients improved in Passias CL modifier, 53.3% in TS-CL modifier, 100% in C2-T3 modifier, 88.9% in C2S modifier, and 81.0% in MGS modifier severity by 2Y. The cohort significantly improved from baseline to 2Y in NDI, NRS Neck, and mJOA, all P <0.05. 59.3% of patients met minimal clinically important difference for NDI, 62.3% for NRS Neck, and 37.3% for mJOA. Ninety-seven patients presented with at least one neurologic deficit at baseline and 63.9% no longer reported that deficit at follow-up. There were 45 (34.6%) cases of distal junctional kyphosis (DJK) (∆DJKA>10° between lower instrumented vertebra and lower instrumented vertebra-2), of which 17 were distal junctional failure (distal junctional failure-DJK requiring reoperation). Patients with the greatest beneficial change were less likely to have had a complication in the two-year follow-up period. CONCLUSION: Correction of CD results in notable clinical and radiographic improvement with most patients achieving favorable outcomes after two years. However, complications including DJK or failure remain prevalent.

The Additional Economic Burden of Frailty in Adult Cervical Deformity Patients Undergoing Surgical Intervention.

SUMMARY OF BACKGROUND DATA: The influence of frailty on economic burden following corrective surgery for the adult cervical deformity (CD) is understudied and may provide valuable insights for preoperative planning. OBJECTIVE: To assess the influence of baseline frailty status on the economic burden of CD surgery. STUDY DESIGN: Retrospective cohort. MATERIALS AND METHODS: CD patients with frailty scores and baseline and two-year Neck Disability Index data were included. Frailty score was categorized patients by modified CD frailty index into not frail (NF) and frail (F). Analysis of covariance was used to estimate marginal means adjusting for age, sex, surgical approach, and baseline sacral slope, T1 slope minus cervical lordosis, C2-C7 angle, C2-C7 sagittal vertical axis. Costs were derived from PearlDiver registry data. Reimbursement consisted of a standardized estimate using regression analysis of Medicare payscales for services within a 30-day window including length of stay and death. This data is representative of the national average Medicare cost differentiated by complication/comorbidity outcome, surgical approach, and revision status. Cost per quality-adjusted life-year (QALY) at two years was calculated for NF and F patients. RESULTS: There were 126 patients included. There were 68 NF patients and 58 classified as F. Frailty groups did not differ by overall complications, instance of distal junctional kyphosis, or reoperations (all P >0.05). These groups had similar rates of radiographic and clinical improvement by two years. NF and F had similar overall cost ($36,731.03 vs. $37,356.75, P =0.793), resulting in equivocal costs per QALYs for both patients at two years ($90,113.79 vs. $80,866.66, P =0.097). CONCLUSION: F and NF patients experienced similar complication rates and upfront costs, with equivocal utility gained, leading to comparative cost-effectiveness with NF patients based on cost per QALYs at two years. Surgical correction for CD is an economical healthcare investment for F patients when accounting for anticipated utility gained and cost-effectiveness following the procedure. LEVEL OF EVIDENCE: III.

CD4+ T-Cell Epitope Prediction by Combined Analysis of Antigen Conformational Flexibility and Peptide-MHCII Binding Affinity.

Antigen processing in the class II MHC pathway depends on conventional proteolytic enzymes, potentially acting on antigens in native-like conformational states. CD4+ epitope dominance arises from a competition among antigen folding, proteolysis, and MHCII binding. Protease-sensitive sites, linear antibody epitopes, and CD4+ T-cell epitopes were mapped in plague vaccine candidate F1-V to evaluate the various contributions to CD4+ epitope dominance. Using X-ray crystal structures, antigen processing likelihood (APL) predicts CD4+ epitopes with significant accuracy for F1-V without considering peptide-MHCII binding affinity. We also show that APL achieves excellent performance over two benchmark antigen sets. The profiles of conformational flexibility derived from the X-ray crystal structures of the F1-V proteins, Caf1 and LcrV, were similar to the biochemical profiles of linear antibody epitope reactivity and protease sensitivity, suggesting that the role of structure in proteolysis was captured by the analysis of the crystal structures. The patterns of CD4+ T-cell epitope dominance in C57BL/6, CBA, and BALB/c mice were compared to epitope predictions based on APL, MHCII binding, or both. For a sample of 13 diverse antigens, the accuracy of epitope prediction by the combination of APL and I-Ab-MHCII-peptide affinity reached 36%. When MHCII allele specificity was also diverse, such as in human immunity, prediction of dominant epitopes by APL alone reached 42% when using a stringent scoring threshold. Because dominant CD4+ epitopes tend to occur in conformationally stable antigen domains, crystal structures typically are available for analysis by APL, and thus, the requirement for a crystal structure is not a severe limitation.

The Clinical Impact of Failing to Achieve Ideal Proportional Realignment in Adult Spinal Deformity Patients.

SUMMARY OF BACKGROUND DATA: The impact of not achieving ideal realignment in the global alignment and proportion (GAP) score in adult spinal deformity (ASD) correction on clinical outcomes is understudied at present. OBJECTIVE: To identify the clinical impact of failing to achieve GAP proportionality in ASD surgery. STUDY DESIGN: Retrospective cohort. METHODS: Operative ASD patients with fusion to S1/pelvis and with pre-(BL) and 2-year (2Y) data were included. Patients were assessed for matching their 6-week (6W) age-adjusted alignment goals. 1 Patients were stratified by age-adjusted match at 6W postoperatively (Matched) and 6W GAP proportionality (proportioned: GAP-P; moderately disproportioned: GAP-MD; severely disproportioned: GAP-SD). Groups were assessed for differences in demographics, surgical factors, radiographic parameters, and complications occurring by 2Y. Multivariable logistic regression was used to assess independent effects of not achieving GAP proportionality on postoperative outcomes for Matched and Unmatched patients. RESULTS: Included: One hundred twenty three ASD patients. At baseline, 39.8% were GAP-SD, and 12.2% GAP-SD at 6W. Of 123 patients, 51.2% (n =63) had more than or equal to one match at 6W. GAP-SD rates did not differ by being Matched or Unmatched ( P = 0.945). GAP-SD/Unmatched patients had higher rates of reoperation, implant failure, and PJF by 2Y postop (all P <0.05). Regressions controlling for age at BL, levels fused, and CCI, revealed 6W GAP-SD/Unmatched patients had higher odds of reoperation (OR: 54 [3.2-899.9]; P =0.005), implant failure (OR: 6.9 [1.1-46.1]; P =0.045), and PJF (OR: 30.1 [1.4-662.6]; P =0.031). Compared to GAP-P or GAP-MD patients, GAP-SD/ Matched patients did not have higher rates of reoperation, implant failure, or junctional failure (all P >0.05). The regression results for both Matched and Unmatched cohorts were consistent when proportionality was substituted by the continuous GAP score. CONCLUSION: In ASD patients who meet age-adjusted realignment goals, GAP proportionality does not significantly alter complication rates. However, GAP proportionality remains an important consideration in patients with sub-optimal age- adjusted alignment. In these cases, severe global disproportion is associated with higher rates of reoperation, implant failure, rod fracture, and junctional failure.

Health-related quality of life measures in adult spinal deformity: can we replace the SRS-22 with PROMIS?

PURPOSE: To determine the validity and responsiveness of PROMIS metrics versus the SRS-22r questionnaire in adult spinal deformity (ASD). METHODS: Surgical ASD patients undergoing ≥ 4 levels fused with complete baseline PROMIS and SRS-22r data were included. Internal consistency (Cronbach's alpha) and test-retest reliability [intraclass correlation coefficient (ICC)] were compared. Cronbach's alpha and ICC values ≥ 0.70 were predefined as satisfactory. Convergent validity was evaluated via Spearman's correlations. Responsiveness was assessed via paired samples t tests with Cohen's d to assess measure of effect (baseline to 3 months). RESULTS: One hundred and ten pts are included. Mean baseline SRS-22r score was 2.62 ± 0.67 (domains = Function: 2.6, Pain: 2.5, Self-image: 2.2, Mental Health: 3.0). Mean PROMIS domains = Physical Function (PF): 12.4, Pain Intensity (PI): 91.7, Pain Interference (Int): 55.9. Cronbach's alpha, and ICC were not satisfactory for any SRS-22 and PROMIS domains. PROMIS-Int reliability was low for all SRS-22 domains (0.037-0.225). Convergent validity demonstrated strong correlation via Spearman's rho between PROMIS-PI and overall SRS-22r (- 0.61), SRS-22 Function (- 0.781), and SRS-22 Pain (- 0.735). PROMIS-PF had strong correlation with SRS-22 Function (0.643), while PROMIS-Int had moderate correlation with SRS-22 Pain (- 0.507). Effect size via Cohen's d showed that PROMIS had superior responsiveness across all domains except for self-image. CONCLUSIONS: PROMIS is a valid measure compared to SRS-22r in terms of convergent validity, and has greater measure of effect in terms of responsiveness, but failed in reliability and internal consistency. Surgeons should consider the lack of reliability and internal consistency (despite validity and responsiveness) of the PROMIS to SRS-22r before replacing the traditional questionnaire with the computer-adaptive testing.

Comparing and Contrasting the Clinical Utility of Sagittal Spine Alignment Classification Frameworks: Roussouly Versus SRS-Schwab.

STUDY DESIGN: Retrospective cohort study of a prospectively collected database. OBJECTIVE: To compare clinical utility of two common classification systems for adult spinal deformity (ASD) and determine whether both should be considered in surgical planning to improve patient outcomes. SUMMARY OF BACKGROUND DATA: Surgical restoration of appropriate Roussouly classification shape or SRS-Schwab ASD classification may improve outcomes. METHODS: ASD patients with pre- and 2-year postop (2Y) radiographic/health-related quality of life (HRQL) data were grouped by "theoretical" and "current" Roussouly type. Univariate analyses assessed outcomes of patients who mismatched Roussouly types at both pre- and 2Y intervals (Mismatched) and those of preoperative mismatched patients who matched at 2-years (Matched). Subanalysis assessed outcomes of patients who improved in Schwab modifiers, and patients who both improved in both Schwab modifiers and matched Roussouly type by 2Y. RESULTS: Included: 515 ASD patients (59 ±â€Š14 yrs, 80% F). Preoperative breakdown of "current" Roussouly types: Type 1 (10%), 2 (54%), 3 (24%), and 4 (12%). Matched and Mismatched groups did not differ in rates of reaching MCID for any HRQL metrics by 2Y (all P > 0.10). Reoperation, PJK, and complications did not differ between Matched and Mismatched (all P > 0.10), but Roussouly Matched patients had toward lower rates of instrumentation failure (17.2% vs. 24.8%, P = 0.038). By 2Y, 28% of patients improved in PT Schwab modifier, 37% in SVA, and 46% in PI-LL. Patients who both Matched Roussouly at 2Y and improved in all Schwab modifiers met MCID for Oswestry Disability Index (ODI) and Scoliosis Research Society (SRS) activity at higher rates than patients who did not. CONCLUSION: Isolated restoration per the Roussouly system was not associated with superior outcomes. Patients who both matched Roussouly type and improved in Schwab modifiers had superior patient-reported outcomes at 2-years. Concurrent consideration of both systems may offer utility in establishing optimal realignment goals.Level of Evidence: 3.

Establishing the minimal clinically important difference for the PROMIS Physical domains in cervical deformity patients.

INTRODUCTION: Patient Reported Outcome Measurement Information System (PROMIS) instruments have been shown to correlate with established patient outcome metrics. The aim of this retrospective study was to determine the MCID for the PROMIS physical domains of Physical Function (PF), Pain Intensity (PI), and Pain Interference (Int) in a population of surgical cervical deformity (CD) patients. METHODS: Surgical CD patients ≥ 18 years old with baseline (BL) and 3-month (3 M) HRQL data were isolated. Changes in HRQLs: ΔBL-3M. An anchor-based methodology was used. The cohort was divided into four groups: 'worse' (ΔEQ5D ≤ -0.12), 'unchanged' (≥0.12, but < -0.12), 'slightly improve' (>0.12, but ≤ 0.24), and 'markedly improved' (>0.24) [0.24 is the MCID for EQ5D]. PROMIS-PF, PI and Int at 3M was compared between 'slightly improved' and 'unchanged'. ROC computed discrete MCID values using the change in PROMIS that yielded the smallest difference between sensitivity ('slightly improved') and specificity ('unchanged'). We repeated anchor-based methods for the Ames-ISSG classification of severe deformity. RESULTS: 140 patients were included. EQ5D groups: 9 patients 'worse', 53 'unchanged', 20 'slightly improved', and 57 'markedly improved'. Patients classified as 'unchanged' exhibited a PROMIS-PF improvement of 2.9 ± 17.0 and those 'slightly improved' had an average gain of 13.3 ± 17.8. ROC analysis for the PROMIS-PF demonstrated an MCID of +2.26, for PROMIS-PI of -5.5, and PROMIS-Int of -5.4. In the Ames-ISSG TS-CL severe CD modifier, ROC analysis found MCIDs of PROMIS physical domains: PF of +0.5, PI of -5.2, and Int of -5.4. CONCLUSIONS: MCID for PROMIS physical domains were established for a cervical deformity population. MCID in PROMIS Physical Function was significantly lower for patients with severe cervical deformity.

Frequency and Implications of Concurrent Complications Following Adult Spinal Deformity Corrective Surgery.

STUDY DESIGN: Retrospective review. OBJECTIVE: Identify co-occurring perioperative complications and associated predictors in a population of patients undergoing surgery for adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: Few studies have investigated the development of multiple, co-occurring complications following ASD-corrective surgery. Preoperative risk stratification may benefit from identification of factors associated with multiple, co-occurring complications. METHODS: Elective ASD patients in National Surgical Quality Improvement Program (NSQIP) 2005 to 2016 were isolated; rates of co-occurring complications and affected body systems were assessed via cross tabulation. Random forest analysis identified top patient and surgical factors associated with complication co-occurrence, using conditional inference trees to identify significant cutoff points. Binary logistic regression indicated effect size of top influential factors associated with complication co-occurrence at each factor's respective cutoff point. RESULTS: Included: 6486 ASD patients. The overall perioperative complication rate was 34.8%; 28.5% of patients experienced one complication, 4.5% experienced two, and 1.8% experienced 3+. Overall, 11% of complication co-occurrences were pulmonary/cardiovascular, 9% pulmonary/renal, and 4% integumentary/renal. By complication type, the most common co-occurrences were transfusion/urinary tract infection (UTI) (24.3%) and transfusion/pneumonia (17.7%). Surgical factors of operative time ≥400 minutes and fusion ≥9 levels were the strongest factors associated with the incidence of co-occurring complications, followed by patient-specific variables like American Society of Anesthesiologists (ASA) physical status classification grade ≥2 and age ≥65 years. Regression analysis further showed associations between increasing complication number and longer length of stay (LOS), (R2 = 0.202, P < 0.001), non-home discharge (R2 = 0.111, P = 0.001), and readmission (R2 = 0.010, P < 0.001). CONCLUSION: For surgical ASD patients, the overall rate of co-occurring perioperative complications was 6.3%. Body systems most commonly affected by complication co-occurrences were pulmonary and cardiovascular, and common co-occurrences included transfusion/UTI (24.3%) and transfusion/pneumonia (17.7%). Increasing number of perioperative complications was associated with greater LOS, non-home discharge, and readmission, highlighting the importance of identifying risk factors for complication co-occurrences.Level of Evidence: 3.

Does Matching Roussouly Spinal Shape and Improvement in SRS-Schwab Modifier Contribute to Improved Patient-reported Outcomes?

STUDY DESIGN: Retrospective review. OBJECTIVE: The aim of this study was to evaluate outcomes of matching Roussouly and improving in Schwab modifier following adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: The Roussouly Classification system of sagittal spinal shape and the SRS-Schwab classification system have become important indicators of spine deformity. No previous studies have examined the outcomes of matching both Roussouly type and improving in Schwab modifiers postoperatively. METHODS: Surgical ASD patients with available baseline (BL) and 1 year (1Y) radiographic data were isolated in the single-center spine database. Patients were classified by their "theoretical" and "current" Roussouly types as previously published. Patients were considered a "Match" if their theoretical and current Roussouly types were the same, or a "Mismatch" if the types differed. Patients were noted as improved if they were Roussouly "Mismatch" preoperatively, and "Match" at 1Y postop. Schwab modifiers at BL were categorized as follows: no deformity (0), moderate deformity (+), and severe deformity (++) for PT, SVA, and PI-LL. Improvement in SRS-Schwab was defined as a decrease in any modifier severity at 1Y. RESULTS: 103 operative ASD patients (61.8 years, 63.1% female, 30 kg/m2) were included. At baseline, breakdown of "current" Roussouly type was: 28% Type 1, 25.3% Type 2, 32.0% Type 3, 14.7% Type 4. 65.3% of patients were classified as Roussouly "Mismatch" at BL. Breakdown of BL Schwab modifier severity: PT (+: 41.7%, ++: 49.5%), SVA (+: 20.3%, ++: 50%), PI-LL (+: 25.2%, ++: 46.6%). At 1 year postop, 19.2% of patients had Roussouly "Match". Analysis of Schwab modifiers showed that 12.6% improved in SVA, 42.7% in PI-LL, and 45.6% in PT. Count of patients who both had a Roussouly type "Match" at 1Y and improved in Schwab modifier severity: nine PT (8.7%), eight PI-LL (7.8%), and two SVA (1.9%). There were two patients (1.9%) who met their Roussouly type and improved in all three Schwab. 1Y matched Roussouly patients improved more in health-related quality of life scores (minimal clinically important difference [MCID] for Oswestry Disability Index [ODI], EuroQol-5D-3L [EQ5D], Visual Analogue Score Leg/Back Pain), compared to mismatched, but was not significant (P > 0.05). Match Roussouly and improvement in PT Schwab met MCID for EQ5D more (P = 0.050). Matched Roussouly and improvement in SVA Schwab met MCID for ODI more (P = 0.024). CONCLUSION: Patients who both matched Roussouly sagittal spinal type and improved in SRS-Schwab modifiers had superior patient-reported outcomes. Utilizing both classification systems in surgical decision-making can optimize postop outcomes.Level of Evidence: 3.

Not Frail and Elderly: How Invasive Can We Go in This Different Type of Adult Spinal Deformity Patient?

STUDY DESIGN: Retrospective review of a single-center spine database. OBJECTIVE: Investigate the intersections of chronological age and physiological age via frailty to determine the influence of surgical invasiveness on patient outcomes. SUMMARY OF BACKGROUND DATA: Frailty is a well-established factor in preoperative risk stratification and prediction of postoperative outcomes. The surgical profile of operative patients with adult spinal deformity (ASD) who present as elderly and not frail (NF) has yet to be investigated. Our aim was to examine the surgical profile and outcomes of patients with ASD who were NF and elderly. METHODS: Patients with ASD 18 years or older, four or greater levels fused, with baseline (BL) and follow-up data were included. Patients were categorized by ASD frailty index: NF, Frail (F), severely frail (SF]. An elderly patient was defined as 70 years or older. Patients were grouped into NF/elderly and F/elderly. SRS-Schwab modifiers were assessed at BL and 1 year (0, +, ++). Logistic regression analysis assessed the relationship between increasing invasiveness, no reoperations, or major complications, and improvement in SRS-Schwab modifiers [Good Outcome]. Decision tree analysis assessed thresholds for an invasiveness risk/benefit cutoff point. RESULTS: A total of 598 patients with ASD included (55.3 yr, 59.7% F, 28.3 kg/m2). 29.8% of patients were older than 70 years. At BL, 51.3% of patients were NF, 37.5% F, and 11.2% SF. Sixty-sis (11%) patients were NF and elderly. About 24.2% of NF-elderly patients improved in SRS-Schwab by 1 year and had no reoperation or complication postoperatively. Binary regression analysis found a relationship between worsening SRS-Schwab, postop complication, and reoperation with invasiveness score (odds ratio: 1.056 [1.01-1.102], P = 0.011). Risk/benefit cut-off was 10 (P = 0.004). Patients below this threshold were 7.9 (2.2-28.4) times more likely to have a Good Outcome. 156 patients were elderly and F/SF with 16.7% having good outcome, with a risk/benefit cut-off point of less than 8 (4.4 [2.2-9.0], P < 0.001). CONCLUSION: Frailty status impacted the balance of surgical invasiveness relative to operative risk in an inverse manner, whereas the opposite was seen amongst elderly patients with a frailty status less than their chronologic age. Surgeons should perhaps consider incorporation of frailty status over age status when determining realignment plans in patients of advanced age.Level of Evidence: 3.

Appropriate Risk Stratification and Accounting for Age-Adjusted Reciprocal Changes in the Thoracolumbar Spine Reduces the Incidence and Magnitude of Distal Junctional Kyphosis in Cervical Deformity Surgery.

STUDY DESIGN: Retrospective cohort study of a prospective cervical deformity (CD) database. OBJECTIVE: Identify factors associated with distal junctional kyphosis (DJK); assess differences across DJK types. SUMMARY OF BACKGROUND DATA: DJK may develop as compensation for mal-correction of sagittal deformity in the thoracic curve. There is limited understanding of DJK drivers, especially for different DJK types. METHODS: Included: patients with pre- and postoperative clinical/radiographic data. Excluded: patients with previous fusion to L5 or below. DJK was defined per surgeon note or DJK angle (kyphosis from LIV to LIV-2)<-10°, and pre- to postoperative change in DJK angle by<-10°. Age-specific target LL-TK alignment was calculated as published. Offset from target LL-TK was correlated to DJK magnitude and inclination. DJK types: severe (DJK<-20°), progressive (DJK increase>4.4°), symptomatic (reoperation or published disability thresholds of NDI ≥ 24 or mJOA≤14). Random forest identified factors associated with DJK. Means comparison tests assessed differences. RESULTS: Included: 136 CD patients (61 ±â€Š10 yr, 61%F). DJK rate was 30%. Postop offset from ideal LL-TK correlated with greater DJK angle (r = 0.428) and inclination of the distal end of the fusion construct (r = 0.244, both P < 0.02). Seven of the top 15 factors associated with DJK were radiographic, four surgical, and four clinical. Breakdown by type: severe (22%), progressive (24%), symptomatic (61%). Symptomatic had more posterior osteotomies than asymptomatic (P = 0.018). Severe had worse NDI and upper-cervical deformity (CL, C2 slope, C0-C2), as well as more posterior osteotomies than nonsevere (all P < 0.01). Progressive had greater malalignment both globally and in the cervical spine (all P < 0.03) than static. Each type had varying associated factors. CONCLUSION: Offset from age-specific alignment is associated with greater DJK and more anterior distal construct inclination, suggesting DJK may develop due to inappropriate realignment. Preoperative clinical and radiographic factors are associated with symptomatic and progressive DJK, suggesting the need for preoperative risk stratification.Level of Evidence: 3.