Comparative Effects of Posterior Versus Total Corpus Callosotomy in a PTZ-Induced Rat Model of Epilepsy

Corpus callosotomy is a palliative surgical procedure for drug-resistant generalized epilepsy that disrupts interhemispheric propagation of epileptic activity. Although total callosotomy (TC) is conventionally performed, posterior callosotomy (PC) may provide comparable seizure control while preserving prefrontal commissural connectivity. Systematic experimental comparisons between the two techniques remain scarce. This study investigated the differential effects of posterior versus total callosotomy in a pentylenetetrazole (PTZ)-induced rat model of epilepsy. Eleven adult male Wistar rats (500–700 g; 8–9 months) underwent epileptogenesis via the PTZ kindling protocol (37.5 mg/kg, i.p.; seven alternating sessions over four weeks). Seizures were classified using the revised Racine scale (grades 0–6c). After establishing stable baseline seizure profiles, animals were randomly assigned to PC (n = 5) or TC (n = 6). One week postoperatively, a PTZ rechallenge was conducted. Statistical analysis included paired t-tests and Wilcoxon signed-rank tests for within-group comparisons, and independent t-tests or Mann–Whitney U tests for between-group comparisons (α = 0.05). No statistically significant differences were observed in seizure duration between preoperative baseline and postoperative rechallenge in either surgical group across all Racine grade categories (all p > 0.05). Likewise, no significant between-group differences were found in postoperative seizure change (PC vs TC; grade 0: p = 0.403; grades 1–4: p = 0.486; grades 5a–5c: p = 0.174; grades 6a–6c: p = 0.177). The TC group demonstrated a consistent directional trend toward shorter high-grade seizure duration (grades 5–6), whereas PC showed a directional tendency toward slightly increased high-grade duration, potentially reflecting residual frontal network synchronization via preserved anterior callosal fibers. These findings indicate that the acute effects of callosotomy are limited in the PTZ model, likely reflecting the diffuse chemically induced nature of ictal discharge and the brief postoperative evaluation window. Future studies employing chronic focal epilepsy models with longer follow-up and electrophysiological verification are warranted to fully characterize the differential effects of each technique.