Treating indeterminate cases of spinal metastases (those with spinal instability neoplastic score [SINS] of 7–12) remains a clinical dilemma, as there are currently no well-defined recommendations for this category. This study aimed to identify the most appropriate approach for patients with indeterminate SINS by reviewing and analyzing published evidence. This comparative effectiveness study used systematic review and meta-analysis. The authors conducted a systematic search in PubMed, Embase, Cochrane Library, and Google Scholar. Inclusion criteria were randomized controlled trials (RCTs), controlled clinical trials (CCTs) and peer-reviewed observational studies (cohort, case-control, and cross-sectional) that provided data on the effectiveness of surgical intervention versus medical management in patients with spinal metastasis having indeterminate SINS. Interventions compared were surgery (vertebrectomy, spinal decompression with or without instrumentation and cement augmentation) and medical management (radiotherapy, including external beam radiotherapy [EBRT] or stereotactic body radiotherapy [SBRT], and chemotherapy). Outcomes analyzed included patients’ functional status, complications, and conversion to surgery/revision surgery. The authors analyzed quantitative data using Review Manager version 5.3 software. Eight studies were included in the qualitative review, and six in the quantitative synthesis, involving a total of 1,312 patients. In patients with spinal metastasis under indeterminate SINS, surgery resulted in less functional decline than medical management (pooled odds ratio [OR] of 0.50; 95% confidence interval [CI] of 0.31-0.81). However, surgery was associated with significantly more complications (OR, 2.6; 95% CI, 1.66-4.08) including wound healing disorders, wound infections, instrumentation failure, thrombosis, and pneumonia. Among patients initially managed medically, 21.19% converted to surgery. Also, in the initial surgery group, conversion to surgery or revision surgery was significantly reduced (OR, 0.19; 95% CI, 0.10-0.34). This study addresses the dilemma of treating spinal metastasis with indeterminate instability, advocating for surgery as the primary intervention due to its potential to improve functional outcomes and quality of life, which may, influence overall survival. Future research could explore a specific SINS threshold as a criterion for recommending surgery.