Minimally invasive surgery for intradural spinal meningioma: A new standard? A comparative study between minimally invasive and open approaches.

BACKGROUND: Some authors used minimally invasive surgery (MIS) in the treatment of spinal cord tumor, but these studies had a small sample sizes and mixed extra- and intra-medullary tumors, resulting in confounding biases. The objectives of the present study were to evaluate the effectiveness and safety of MIS for spinal meningioma resection in comparison with open surgery (OS). METHODS: Consecutive patients with spinal meningioma who received either MIS or OS were included. Data for extent of resection, functional outcome, postoperative morbidity and recurrence were collected. RESULTS: A total of 48 patients (with 51 spinal meningiomas) were included. Eighteen underwent MIS and 30 OS. Meningioma volume and location did not differ significantly between groups: tumors were predominantly thoracic (n=39, 76.5%) and voluminous (occupying more than 50% of the spinal canal: n=43, 84.3%). In the MIS group, patients were older (mean age: 66.5 vs. 56.4years, P=0.02) and more fragile (mean ASA score: 2.0 vs. 1.6, P=0.06). In the MIS group, the surgical procedure was shorter (mean duration: 2.07 vs. 2.56h, P=0.04), blood loss lower (mean: 252 vs. 456mL, P=0.02), and hospital stay shorter (mean: 6.6 vs. 8.1days). Surgery improved the modified McCormick scale (P<0.0001) irrespective of the surgical technique. MIS led to no significant differences in extent of resection or postoperative morbidity. Mean follow-up was 46.6 months. At last follow-up, 91.7% (n=44) of patients were free of progression; all cases of tumor progression (n=4) occurred in the OS group. CONCLUSIONS: MIS outperformed OS in the management of intradural spinal meningioma, irrespective of location and volume. MIS appears to be particularly suitable for elderly and fragile patients.