Perioperative outcomes after minimally invasive and open surgery for treatment of spine metastases: a systematic review and meta-analysis

OBJECTIVE This systematic review and meta-analysis compared minimally invasive surgery (MIS) to open surgery for treatment of spinal metastases with respect to perioperative outcomes. Few studies have systemically assessed the body of evidence on this topic. METHODS A systematic review of EMBASE and PubMed from database inception to December 2023 was performed to identify studies comparing MIS with open surgery for the treatment of spine metastases. Nine outcomes were collected: estimated blood loss (EBL), operative time, hospital length of stay (LOS), risk of revision, risk of neurological deterioration, likelihood of receiving postoperative radiation therapy, time to radiation therapy, time to chemotherapy, and treatment of pain measured through patient-reported visual analog scale (VAS) scores. Meta regression was used to estimate adjusted mean differences (aMDs) and adjusted odds ratios (aORs) for outcomes. Certainty of evidence was appraised using the Grading of Recommendations, Assessment, Development and Evaluations approach. RESULTS There were 34 eligible studies including 1656 patients with spinal metastases; 904 (54.6%) patients were treated with MIS and 752 (45.4%) were treated with open surgery. MIS was associated with significantly less blood loss (aMD -602 mL, 95% CI -1204 to -0.2 mL; I-2 = 97%) with a moderate certainty of evidence. MIS was found to be noninferior with respect to operative time (aMD -2.6 minutes, 95% CI -53.3 to 48.1 minutes; I-2 = 88%), risk of revision (aOR 0.9, 95% CI 0.8-1.1; I-2 < 0.01), risk of neurological deterioration (aOR 0.9, 95% CI 0.8-1.0; I-2 < 0.01), likelihood of postoperative radiation therapy (aOR 0.9, 95% CI 0.7-1.4; I-2 < 0.01), and postoperative VAS score (aMD -0.6, 95% CI -1.5 to 0.4; I-2 = 52%) with low certainty of evidence. MIS was associated with significantly shorter time to chemotherapy (MD -0.9 weeks, 95% CI -1.9 to -0.01 weeks; I-2 = 22%), with very low certainty of evidence. Inferences for LOS and time to radiation were indeterminate; however, we found a trend toward earlier radiation therapy with MIS that was significant in the subgroup of patients treated with decompression and fusion. CONCLUSIONS Treatment with MIS compared with open surgery was associated with reduced EBL, shorter time to chemotherapy, similar operative time, and similar reductions in postoperative pain. Limitations were largely due to heterogeneity across studies. Future research among subgroups is very likely to improve certainty in the comparative effect estimates.