Post-section recruitment of epileptiform discharges in electrocorticography during callosotomy in 48 patients with Lennox-Gastaut syndrome.

We aimed to clarify the relationships between post-sectional recruitment of epileptiform discharges (PRED) seen in electrocorticograms (ECoG) during callosotomy in patients with Lennox-Gastaut syndrome (LGS) and postoperative seizure outcome. We retrospectively analyzed ECoG obtained during subtotal callosotomy (6 cm) in 48 patients with LGS (32 males, 16 females; age range, 1-20 years; mean age, 7.6 years) from July 1993 to November 1996 and compared recorded findings with postoperative seizure outcome. At analysis, all patients had been followed postoperatively for more than 10 years. Of 48 patients, 15 (31.3%) had PRED in their post-section ECoG. Of these patients, 11 (73%) achieved significant (at least 50%) overall seizure reduction postoperatively. The phenomenon of PRED in callosotomy did not predict a better postoperative seizure outcome (p>0.05). We concluded that post-sectional ECoG recruitment of electrical discharges during callosotomy did not predict postoperative prognosis. However, this finding should be supported and elucidated by further studies. The heterogenous ECoG findings during callosotomy in our series might suggest a complicated role of the corpus callosum in the epileptogenesis of Lennox-Gastaut syndrome.