Predictors of survival and functional outcomes after spinal surgery for multiple myeloma: a nationwide study of 200 patients.

Abstract

To identify predictors of survival after spinal surgery for multiple myeloma (MM) and evaluate postoperative ambulation and pain at six weeks. This retrospective nationwide cohort study included 200 patients from the Swedish Spine Registry and the Swedish Myeloma Registry (2011-2023). Survival was estimated using Kaplan-Meier methods. Multivariable Cox regression models assessed predictors including International Staging System (ISS) stage, hemoglobin, age, preoperative ambulation, and synchronous (≤ 90 days from MM diagnosis) versus metachronous (> 90 days) spinal involvement. Median overall survival from MM diagnosis was 72 months (95% CI, 49.4-94.6), and median postoperative survival was 58 months (95% CI, 38.3-77.7). Multivariable analysis identified ISS stage III (HR, 3.2; 95% CI, 1.2-8.0), older age (HR, 1.03; 95% CI, 1.01-1.06), preoperative non-ambulation (HR, 2.4; 95% CI, 1.3-4.2), and metachronous disease (HR, 3.3; 95% CI, 1.7-6.3) as independent predictors of poorer survival. Paired preoperative and 6-week postoperative data were available for 94 of 200 patients (47%) for ambulation and 113 of 200 patients (56.5%) for pain. Among patients with paired data, 64% of initially non-ambulatory patients regained ambulation, 96% of initially ambulatory patients maintained ambulation, and 72% (81/113) reported improved pain. Advanced ISS stage, older age, preoperative non-ambulation, and metachronous disease were independent predictors of reduced survival after spinal surgery for MM. In selected patients with available follow-up data, surgery restored or preserved mobility and provided pain relief, supporting its role in the multidisciplinary management of spinal manifestations of MM.