OBJECTIVE Surgical correction of cervical deformity (CD) has been associated with superior alignment and functional outcomes. It has not yet been determined whether baseline or postoperative T1 slope (T1S) and C2 slope (C2S) correlate with health-related quality-of-life (HRQoL) metrics and radiographic complications, such as distal junctional kyphosis (DJK) and distal junctional failure (DJF). The objective of this study was to determine the impact of T1S and C2S deformity severity on HRQoL metrics and DJF development in patients with CD who underwent a cervical fusion procedure. METHODS All operative CD patients with upper instrumented vertebra above C7 and preoperative (baseline) and up to 2-year postoperative radiographic and HRQoL data were included. CD was defined as meeting at least one of the following radiographic parameters: C2–7 lordosis < −15°, TS1–cervical lordosis mismatch > 35°, segmental cervical kyphosis > 15° across any 3 vertebrae between C2 and T1, C2–7 sagittal vertical axis > 4 cm, McGregor’s slope > 20°, or chin-brow vertical angle > 25°. Spearman’s rank-order correlation and linear regression analysis assessed the impact of T1S and C2S on HRQoL metrics (Neck Disability Index [NDI], modified Japanese Orthopaedic Association [mJOA] scale, EuroQOL 5-Dimension Questionnaire [EQ-5D] visual analog scale [VAS] score, and numeric rating scale [NRS]–neck) and complications (DJK, DJF, reoperation). Logistic regression and a conditional inference tree (CIT) were used to determine radiographic thresholds for achieving optimal clinical outcome, defined as meeting good clinical outcome criteria (≥ 2 of the following: NDI < 20 or meeting minimal clinically important difference, mild myelopathy [mJOA score ≥ 14], and NRS-neck ≤ 5 or improved by ≥ 2 points), not undergoing reoperation, or developing DJF or mechanical complication by 2 years. RESULTS One hundred five patients with CD met inclusion criteria. By surgical approach, 14.7% underwent an anterior-only approach, 46.1% a posterior-only approach, and 39.2% combined anterior and posterior approaches. The mean baseline radiographic parameters were T1S 28.3° ± 14.5° and C2S 25.9° ± 17.5°. Significant associations were found between 3-month C2S and mJOA score (r = −0.248, p = 0.034), NDI (r = 0.399, p = 0.001), EQ-5D VAS (r = −0.532, p < 0.001), NRS-neck (r = 0.239, p = 0.040), and NRS-back (r = 0.264, p = 0.021), while significant correlation was also found between 3-month T1S and mJOA score (r = −0.314, p = 0.026), NDI (r = 0.445, p = 0.001), EQ-5D VAS (r = −0.347, p = 0.018), and NRS-neck (r = 0.269, p = 0.049). A significant correlation was also found between development of DJF and 3-month C2S (odds ratio [OR] 1.1, 95% confidence interval [CI] 1.01–1.1, p = 0.015) as well as for T1S (OR 1.1, 95% CI 1.01–1.1, p = 0.023). Logistic regression with CIT identified thresholds for optimal outcome by 2 years: optimal 3-month T1S < 26° (OR 5.6) and C2S < 10° (OR 10.4), severe 3-month T1S < 45.5° (OR 0.2) and C2S < 38.0° (no patient above this threshold achieved optimal outcome; all p < 0.05). Patients below both optimal thresholds achieved rates of 0% for DJK and DJF, and 100% met optimal outcome. CONCLUSIONS The severity of CD, defined by T1S and C2S at baseline and especially at 3 months, can be predictive of postoperative functional improvement and occurrence of worrisome complications in patients with CD, necessitating the use of thresholds in surgical planning to achieve optimal outcomes.

Study Design. Retrospective single-center, consecutively enrolled database of adult spinal deformity (ASD) patients. Objective. The aim of this study was to assess the performance of the mASD-FI in predicting clinical and patient-reported outcomes after ASD-corrective surgery. Summary of Background Data. The recently described modified Adult Spinal Deformity frailty index (mASD-FI) quantifies frailty of ASD patients, but the utility of this clinical prediction tool as a means of prognosticating postoperative outcomes has not been investigated. Methods. ASD patients with available mASD-FI scores and HRQL data at presentation and 2-years postop were included. Patients were stratified by mASD-FI score using published cutoffs: not frail (NF <7), frail (F, 7–12), severely frail (SF, >12). Analysis of vaiance assessed differences in patient factors across frailty groups. Linear regression assessed the relationship of mASD-FI with length of stay (LOS) and HRQLs. Multivariable logistic regression revealed how frailty category predicted odds of complications, infections and reoperation. Results. A total of 509 patients included (59 years, 79%F, 27.7 kg/m2). The cohort presented with moderate baseline deformity: sagittal vertical axis (83.7 mm ± 71), PT (12.7° ± 10.8°), PI-LL (43.1° ± 21.1°). Mean preoperative mASD-FI score was 7.2, frailty category: NF (50.3%), F (34.0%), SF (15.7%). Age, BMI, and Charlson Comorbidity Index increased with frailty categories (all P < 0.001); however, fusion length (P = 0.247) and osteotomy rate (P = 0.731) did not. At baseline, increasing frailty was associated with inferior Oswestry Disability Index (ODI), EuroQol 5-Dimension Questionnaire (EQ-5D), SRS-22r, Pain Catastrophizing Scale, and NRS Back and Leg (all P < 0.001). Greater frailty was associated with increased LOS and reduced postoperative HRQL. Controlling for complication incidence, baseline mASD-FI predicted 2 year postop scores for year ODI (b = 0.7, 0.58–0.8, P < 0.001) SRS (b = −0.023, −0.03 to −0.02, P < 0.001), EQ-5D (b = −0.003, −0.004 to −0.002, P < 0.001). F and SF were associated with greater odds of unplanned revision surgery and complications. Conclusion. Higher preoperative mASD-FI score was associated with significantly greater complications, higher rate of unplanned reoperations and lower postoperative HRQL in this investigation. The mASD-FI provides similar prognostic utility while reducing burden for surgeons and patients.

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