Bifocal Surgery for Malignant Spinal Lesions is Associated with Shorter Postoperative Survival and Higher Postoperative Complication Rates Compared to Monofocal Surgery.

Abstract

Malignant spinal lesions (MSL) frequently occur in advanced stages of malignancies and often necessitate surgical stabilization. Monofocal spinal surgery, defined as surgery at a single spinal region using one approach and construct, is commonly performed. However, the impact of bifocal surgical intervention, a single-stage procedure involving two distinct surgical interventions at anatomically separate spinal regions (e.g., cervical and thoracic spine) is not as common. Its relative effect on survival and postoperative outcomes remains unclear. To compare survival, neurological status, and postoperative complication rates between patients undergoing monofocal versus bifocal spinal surgery for malignant spinal lesions. Retrospective matched-pair cohort study conducted at a tertiary care university medical center. A total of 94 patients (47 after bifocal and 47 after monofocal surgery), matched for age, sex, Eastern Cooperative Oncology Group Performance Status (ECOG) score, tumor type, and disease burden, who underwent spinal surgery for malignant spinal lesions between 2018 and 2024, were included in the study. All solid malignant lesions were metastatic, while patients with multiple myeloma presented with multiple osteolytic spinal lesions consistent with systemic disease involvement. No primary spinal tumors were included in this study. Primary outcome: postoperative survival. neurological function (ASIA score), and postoperative complications (e.g., pneumonia, wound infection, transfusion requirement). A retrospective matched-pair cohort study was conducted. To ensure comparability and account for potential differences in disease burden, patients were rigorously matched based on key demographic and clinical variables, including age, gender, tumor subtype, ECOG status, and tumor burden. This matching process ensured that any observed differences in outcomes were attributable to surgical approach rather than baseline disparities in disease severity. Postoperative neurological status was evaluated using ASIA scores, and complications were recorded. Survival analysis was conducted using Kaplan-Meier survival curves. Differences between curves were assessed using the Log-rank (Mantel-Cox) test. Paired nominal data were analyzed using McNemar's test, while paired ordinal data were analyzed using the non-parametric Wilcoxon matched pairs signed rank test. P-values < 0.05 were considered statistically significant. In patients with solid MSL (lung, breast, prostate, renal cancer), bifocal surgery was associated with significantly shorter median survival compared to monofocal surgery (74 vs. 313 days, p < 0.0001). Subgroup analyses confirmed this pattern across all solid tumor types. In contrast, survival was similar in multiple myeloma patients (179 vs. 183 days, p > 0.05). Postoperative ASIA scores declined significantly after bifocal surgery in both solid malignancies and myeloma patients, while remaining stable in monofocal groups. Complication rates, including pneumonia (solid MSL: 44.7% vs. 8.5%, p < 0.0001), wound infections (53.2% vs. 12.8%, p < 0.001), and transfusion requirements (70.2% vs. 17.1%, p < 0.0001), were significantly higher in bifocal cases. Bifocal surgery for solid tumor-related MSL is associated with markedly impaired survival and increased postoperative morbidity compared to monofocal approaches. These findings support a cautious, individualized approach to surgical planning in patients with multifocal spinal disease, with consideration of alternative local therapies when feasible.