Survival and Prognostic Factors After Surgery in Single Spinal Metastasis: Comparison of Isolated-Single Spinal Metastasis and Single Spinal Metastasis With Other Metastasis

Study Design: Retrospective cohort study. Objectives: This study aimed to evaluate the survival period in patients with a single spinal metastasis (SSM), subsequently comparing those with isolated-single spinal metastasis (I-SSM) and single spinal metastasis with other metastasis (O-SSM) after surgery, and to identify prognostic factors affecting their survival. Methods: A total of 135 patients were included, with 24 patients in the I-SSM group and 111 in the O-SSM group. Survival analysis was utilized to assess the survival of SSM patients, followed by a comparison of survival rates between the two groups. Univariate and multivariate analyses were conducted to identify significant prognostic factors for survival. Results: The overall median survival period for patients with single spinal metastasis (SSM) was 10.2 ± 1.8 months. Specifically, the median survival was 15.7 ± 5.7 months in the I-SSM group and 10.2 ± 1.5 months in the O-SSM group. The difference in survival periods between the two groups was not statistically significant (P = 0.345). Significant independent prognostic factors for survival included preoperative Karnofsky Performance Status (KPS) of 50 – 70 (OR 0.51, P = 0.017) and 80 – 100 (OR 0.46, P = 0.012), postoperative ambulatory status (OR 1.19, P = 0.028), and primary malignancy site [Group B (OR 2.67, P = 0.021), Group C (OR 2.90, P = 0.016)]. Conclusions: Patients with SSM have a median survival of 10.2 months, with no significant difference in postoperative survival between the I-SSM and O-SSM groups. Significant prognostic factors influencing the survival period after surgery include preoperative KPS, postoperative ambulatory status, and the primary malignancy site.