Surgical Versus Nonoperative Treatment for Adult Spinal Deformity

STUDY DESIGN: Retrospective comparative study using prospectively collected data from a multicenter adult spinal deformity (ASD) registry across six centers, with propensity score (PS) matching to compare surgical versus nonoperative management. OBJECTIVE: To compare two-year patient-reported outcomes and serious adverse events after surgical versus nonoperative management of adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: Randomized trials comparing operative and nonoperative treatment for ASD are rarely feasible, and ASD presents heterogeneous clinical and radiographic features, complicating treatment decisions. Propensity score methods can reduce measured confounding and strengthen comparative effectiveness estimates from observational cohorts. MATERIALS AND METHODS: Consecutive adults meeting radiographic criteria for ASD were identified from six participating centers. The primary endpoint was the change in Oswestry Disability Index (ODI) at two years; secondary endpoints included SRS-22 outcomes. Propensity scores for surgery were estimated using logistic regression, including age, sex, body mass index, major Cobb angle, pelvic incidence-lumbar lordosis mismatch, global tilt, pelvic tilt, baseline ODI, and SRS-22 total score. One-to-one nearest-neighbor matching (caliper 0.25) generated balanced pairs. Outcomes were compared within the matched cohort. RESULTS: Among 764 screened patients, 580 were eligible (338 surgical; 242 nonoperative). Propensity score matching produced 160 well-balanced pairs (n=320). In the matched cohort, the mean age was ~45 years in both groups. At two years, ODI improvement was greater after surgery than after nonoperative care (-19.4±14.2 vs. -4.2±12.3; P <0.001); 72% of surgical patients versus 29% of nonoperative patients achieved a clinically meaningful ODI improvement (≥15 points; P <0.001). SRS-22 outcomes favored surgery, including a higher two-year SRS-22 total score (3.95±0.67 vs . 3.46±0.75; P <0.0001) and a higher proportion achieving MCID for SRS-22 total score (81.3% vs . 36.9%; P <0.001). CONCLUSION: In a multicenter PS-matched ASD cohort largely representing younger patients with mild-to-moderate baseline impairment, surgery was associated with superior two-year disability and HRQoL outcomes compared with nonoperative care.