Outcomes, patient acceptable symptom state, complications, and predictors after surgical correction of adult spinal deformity – a retrospective observational study

Purpose: Adult spinal deformity surgery (ADS) has been associated with moderate results and a high risk of complications. Patient-acceptable symptom state (PASS), complications, and predictors of outcome may not be sufficiently documented. Purpose: To reassess PASS by the Oswestry Disability Index (ODI), describe reoperations, and study predictors for outcomes after ADS for the target population. Methods: This retrospective and cross-sectional observational survey assessed surgically corrected adult patients with degenerative and posttraumatic spinal deformities. Patients responded to PROM surveys at a median of 51 months (Q1: 30, Q3: 74). Treatment success was assessed using the Global Perceived Effect (GPE), and we employed ROC analysis to determine the corresponding PASS ODI cut-off. Reoperations were documented in electronic patient records (EPRs) with a minimum follow-up of 60 months (median; 80.5, Q1; 65.8, Q3; 107.3). Potential predictors for ODI were examined by linear regression. Results: We identified 82 adult patients with surgically treated deformities at two Norwegian hospitals. PASS was below 32 ODI points (AUC = 0.838, 95% CI: 0.727–0.950), and 24 of 59 (41%) patients achieved PASS. Regression analysis revealed that female gender (B = 12.6, 95% CI = 2.1–23.0, p = 0.019) and smoking (B = 14.4, 95% CI = 1.0-27.9, p = 0.036) predicted worse postoperative ODI. Conclusion: In this retrospective and cross-sectional observational study of adult spinal deformity patients, about 2 of 5 achieved a PASS ODI value below 32 ODI points. Over half of the patients required revision surgery within five years following the index surgery. Female gender and smoking predicted worse postoperative ODI.