BPC228
Best Paper (Clinical)
Effect of Psoas Muscle Quantity and Density on Postoperative Outcomes in Patients with Metastatic Spine Tumors
Woon Theng Heng1, Wen Po1, Jiong Hao Jonathan Tan5, James Thomas Patrick Decourcy Hallinan2, Li Feng Tan3; Liang Shen4, Kumar Satyanarayan Naresh5, Jiong Hao5
1Department of Orthopaedic and Spine Surgery, National University Health System, Singapore; 2Department of Diagnostic Imaging, National University Hospital, Singapore; 3Healthy Ageing Programme, Alexandra Hospital, National University Health System, Singapore; 4Medicine Biostatistics Unit, National University of Singapore, Singapore; 5National University Spine Institute, National University Health System, Singapore, University Spine Centre, National University Hospital, Singapore
Introduction: Sarcopenia, characterized by low muscle strength and mass, has been associated with adverse surgical outcomes. This study aims to evaluate the influence of psoas muscle quantity and quality, as a surrogate for sarcopenia, on postoperative outcomes in patients undergoing surgery for metastatic spine tumors (MSTs), including delays in adjuvant oncologic therapy, observed versus prognosticated survival, postoperative infection, and ambulatory status.
Materials and Methods: We retrospectively analyzed 260 patients who underwent surgery for MSTs between 2005 and 2022. Sarcopenia was quantified using total psoas area normalized to vertebral body area (TPA/VBA) and psoas muscle density (PMD). Associations with outcomes were evaluated using two-sample T-test and multivariate logistic regression adjusted for age, preoperative ECOG status, Charlson Comorbidity Index and Oswestry Spinal Risk Index (p<0.05).
Results: 260 patients (mean age 61.5 ± 10.7 years; 50.4% male) were included. Males demonstrated significantly higher TPA/VBA compared with females (1.15 ± 0.32 vs 0.91 ± 0.31, p < 0.001) while PMD was comparable between sexes (46.50 ± 8.16 vs 44.60 ± 10.34, p = 0.114). On multivariate analysis, lower muscle quantity and quality were associated with delays in initiation of systemic therapy. In females, both lower TPA/VBA (OR 0.160, 95% CI 0.040–0.639; p = 0.01) and lower PMD (OR 0.955, 95% CI 0.914–0.997; p = 0.04) were independently associated with treatment delay. In males, only lower PMD was independently associated with treatment delay (OR 0.957, 95% CI 0.927–0.988; p = 0.007). Higher PMD in males was significantly associated with longer observed relative to prognosticated survival (OR 1.143, 95% CI 1.071–1.219; p < 0.001), whereas no such association was observed in females. Postoperative complication rates included urinary tract infection (16.2%), pneumonia (11.5%), and thromboembolic events (6.5%), with no significant associations between TPA/VBA or PMD and postoperative infection or ambulatory outcomes.
Conclusions: Reduced psoas muscle quality was independently associated with treatment delays and survival in patients undergoing surgery for metastatic spine tumors, demonstrating stronger prognostic value than TPA/VBA. Prospective validation is warranted to confirm its role in preoperative risk stratification.