Minimal Invasive Surgery Instrumented Fusion versus Conventional Open Surgical Instrumented Fusion for the Treatment of Spinal Metastases: A Systematic Review and Meta-analysis.

PURPOSE: In this study, we aimed to compare the minimally invasive instrumented fusion ± decompression (MIS) versus conventional open surgical instrumented fusion ± decompression (COS) for the treatment of spinal metastases. METHODS: We performed a systematic literature search through PubMed, SCOPUS, EuropePMC, and Cochrane Central Database using the keywords "minimal invasive surgery" OR "minimally invasive surgery" OR "mini-open" AND "conventional open surgery" OR "traditional open surgery" OR "open surgery" AND "spinal metastasis". The outcome of interests were complications, neurological improvement, length of stay, intraoperative blood loss, transfusion rate, and operative duration. RESULTS: There were a total of 8 studies comprising of 486 patients. Complications were less frequent in MIS compared to COS (OR 0.51 [0.30, 0.84], p=0.01, I2: 0%). Major complications related to surgery were less in the MIS group (OR 0.42 [0.21, 0.84], p=0.01; I2: 0%). The rate of neurological improvement was similar in both groups (OR 1.01 [0.64, 1.59], p=0.95, I2: 0%). MIS was associated with less blood loss (mean difference -690.00 mL [-888.31, -491.69], p<0.001; I2: 56%), and lower transfusion rate compared to COS (OR 0.27 [0.11, 0.66], p=0.004; I2: 50%). Length of surgery was similar in both groups (mean difference -12.49 minutes [-45.93, 20.95], p=0.46; I2: 86%). MIS resulted in shorter length of stay compared to COS (mean difference -3.58 days [-6.90, -0.26], p=0.03; I2: 89%). CONCLUSION: MIS was associated with lower complications, blood loss, transfusion rate, and shorter length of stay with a similar rate of neurological improvement and length of surgery compared to COS.