Image-guided posterior callosotomy: Optimizing disconnection with DTI tractography and neuronavigation

Corpus callosotomy remains a palliative option for drug-refractory epilepsy with drop attack. However, traditional approaches lack precision, which leads to inconsistent outcomes and cognitive deficits. Advances in tractography and neuronavigation have offered enhanced surgical targeting. This study aimed to assess the safety, efficacy, and feasibility of tractography-guided neuronavigation in posterior callosotomy to optimize the disconnection of motor fibers and improve seizure control.

This retrospective study was conducted between August 2023 and February 2025 in six patients with refractory epilepsy and drop attacks. Preoperative 1.5-Tesla MRI tractography, processed with Medtronic StealthViz, generated 3D motor fiber reconstructions that were integrated into a neuronavigation system. Posterior callosotomy utilized intraoperative neuronavigation with superimposed tractography to define a precise "fiber-based stopping point," ensuring complete transection of the targeted motor callosal fibers. Postoperative CT scans and 3-month tractography were used to assess complications and residual fibers. Nonparametric tests were used to evaluate seizure frequency and correlations.

Complete fiber sectioning was achieved in four patients (100 %), and two had partial sectioning (82.1 % and 89.26 %). A strong exploratory monotonic association was observed (Spearman ρ = 1.00; p = 0.0028): complete sectioning yielded a 100 % drop attack reduction in all four cases, while partial sectioning resulted in 75.0 % and 85.7 % reductions, respectively. Cognitively, two patients reported improvement, and four reported no change. No motor deficits or neuronavigation-related complications were reported, the operative duration was comparable to that of historical cases.

Integrating DTI-based tractography with neuronavigation in posterior callosotomy is feasible and safe, and significantly enhances surgical precision. This approach allows the targeted transection of motor callosal fibers, leading to superior seizure control and stable or improved cognitive outcomes, thereby validating the mechanistic role of these pathways in drop attacks. We advocate fiber-informed neuronavigation to personalize and optimize outcomes in posterior callosotomy.