Objective: Decompression with instrumented fusion is a common approach for treating spinal metastatic disease. However, in many cases, poor bone quality and compromised general condition increase the likelihood of mechanical failure and other complications. This study investigated complications, including those related to surgery, following decompression and fusion in patients with spinal metastatic disease.Methods: A study at a single tertiary medical center focusing on surgical details and perioperative complications was performed on 35 patients who underwent spinal surgery due to metastatic spinal disease based on a review of a prospective database. Data on patients' underlying conditions and the status of the primary tumors were collected, and various complications that occurred within the first month after surgery were analyzed.Results: During the study, 35 patients (mean age, 66.5 years; 26 men) were enrolled. The most frequent primary cancers were lung (34%) and prostate cancer (17%), followed by liver and breast cancer and others. The overall complication rate was 37% (14% surgery-related complications, 23% general complications). In all cases, surgery was performed due to lower extremity weakness, and 59% of patients showed improvements in motor function after surgery. Furthermore, 23% of patients regained the ability to walk.Conclusion: Surgery for spinal metastasis is frequently performed as an emergency due to the severity of symptoms such as lower extremity weakness. Despite a high risk of acute complications, the procedure has significant benefits, including improvement in weakness and recovery of walking ability. Therefore, proactive treatment using appropriate surgical techniques is recommended.