Abstracts

Rationale: MRI-guided laser interstitial thermal therapy for corpus callosotomy (MRIgLITT-CC) offers palliation of intractable atonic, tonic, and generalized tonic-clonic seizures, especially those leading to drop events. This multi-institutional study investigates technical variations, extent of ablation, and need for additional surgery in pediatric patients undergoing MRIgLITT-CC.


Methods: This multi-institutional retrospective study included pediatric patients with medically intractable epilepsy undergoing MRIgLITT-CC as palliative epilepsy surgery. Study authors at each institution determined subject candidacy for MRIgLITT-CC based on standard pre-operative evaluations. 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 at each site. 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. Different trajectories were used based on surgeon preference and individual subject anatomy. 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, including 100% coverage for complete MRIgLITT-CC via 3 (4/6) or 4 (3/6) trajectories (p = 0.6). Three subjects (11%) required repeat callosal surgery (completion following anterior corpus callosotomy, 2 [7%]; and open surgical corpus callosotomy, 1 [4%]). 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).


Conclusions: 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. This study explored technical and radiographic details of MRIgLITT-CC as a precursor to a comparative study with standard open surgical corpus callosotomy.


Funding: Please list any funding that was received in support of this abstract.: N/A