131 Multi-Institutional Study on MRI-guided Laser Interstitial Thermal Therapy for Corpus Callosotomy (MRIgLITT-CC): Technique Variation, Ablation Coverage, and Need for Additional Surgery

Abstract

INTRODUCTION: MRI-guided laser interstitial thermal therapy for corpus callosotomy (MRIgLITT-CC) offers palliation of intractable drop events and atonic, tonic, and generalized tonic-clonic seizures. METHODS: This multi-institutional retrospective study included pediatric patients with medically intractable epilepsy undergoing MRIgLITT-CC. Surgical details, post-operative radiographic results, and need for additional epilepsy surgery were recorded. Percent coverages of the intended ablation zones (anterior, complete, or posterior corpus callosotomy) were estimated from MRI. Data were summarized using descriptive statistics and compared using Chi-square tests. RESULTS: A total of 27 subjects (18 male, 9 female) with mean age 13 years +/- 5 years (4 years, 21 years) underwent planned complete (13, 48%), anterior (11, 41%), or posterior (3, 11%) MRIgLITT-CC. Planned complete MRIgLITT-CC entailed 2 (1/13, 8%), 3 (6/13, 46%), or 4 (6/13, 46%) trajectories with 100% (8/13, 62%) or 95-99% (5/13, 38%) coverage of the planned callosal ablation zone. Anterior MRIgLITT-CC cases included 1 (1/11, 9%), 2 (8/11, 73%), or 3 (1/11, 9%) trajectories to achieve 100% (7/11, 64%), 95-99% (2/11, 18%), 90-94% (1/11, 9%), or <90% (1/11, 9%) coverage of the planned callosal ablation zone. There were no significant differences in percent coverage of intended ablation zone as a function of trajectory number (p = 0.6). Three subjects (11%) required repeat callosal surgery while four subjects (15%) underwent additional vagus nerve stimulator (VNS) insertion during clinic follow-up (mean 11.7 months +/-10.6 months; [0.4 months, 37.1 months]). The need for repeat callosal surgery differed significantly between subjects with 100% and less than 100% ablation coverage (0/16 vs. 3/11, p = 0.03). CONCLUSION: In this multi-institutional study, MRIgLITT-CC yielded 100% or 95-99% coverage of the intended callosal ablation zone in most subjects. Trajectory variation between centers did not impact percent coverage of the intended ablation zone. Few subjects required repeat callosal surgery, particularly those with less than 100% ablation zone coverage, or additional VNS insertion.