Dados do Trabalho

Título

Selective posterior callosotomy for refractory drop attacks and generalized motor seizures: resetting the electrical equilibrium of the brain

Introdução

Drop attacks (DA) and generalized motor seizures (GMS) are malignant types of epileptic seizures in patients with diffuse brain dysfunction. EEGs have encephalopathic generalized discharges and antiseizure medication usually fails. Selective posterior callosotomy (SPC) sections the posterior half of the corpus callosum (CC) and disrupts bilateral synchrony of motor and premotor cortices, sparing prefrontal connectivity.

Objetivo

To confirm that SPC is effective to control DA and study the effect of the procedure in controlling GMS.

Método

31 patients with SPC were prospectively followed for at least 4 years, with a median follow up of 6.2 years (IR: 8.9). Pre- and post-operative frequency of DA and of GMS were quantified, scores in a 13-point scale of functionality in daily living were obtained and VEEG and MRI were performed. In a subgroup of 12 patients, secondary bilateral epileptiform discharges and generalized electrographic seizures were quantified at every 10 seconds of 24h EEGs before and after SPC.

Resultados

All had DA. Median monthly pre-op frequency was 225 (IR: 187.5) and reduced to 0 (IR: 3.5). 17 (54,8%) achieved complete control of DA. The other 14 had a monthly median frequency of 135 (IR: 120) pre-op, and of 2.5 post-op (IR: 59.5). 6 of the 14 (42.8%) had more than 90% reduction in frequency. Thus, 23 of 31 (74.2%) had complete or >90% control of DA. 22 (71%) had daily falls pre-op, reduced to 4 (13%) after SPC (p =0.0001). 15 had at least monthly GMS with a median pre-op frequency of 60/month (IR: 187.5), reduced to 8 (IR: 3.5). 4 (28,5%) with a pre-op median monthly frequency of 87,5 (IR: 220) achieved complete control of GMS. The other 11 had a median monthly frequency of 60,5 attacks (IR: 120) pre-op and of 20 after SPC (IR: 59.5). 8 of 15 (53%) had complete or >90% control of GMS. Pre-operatively, 7 (46%) had daily GMS, reduced to 3. Mean absolute number of bilateral synchronic EEG discharges was 2122 (+/- 3897) pre-op and 2 (+/- 298) post-op (p<0.002). Likewise, mean absolute number of generalized electrographic seizures was 62 (+/- 177) pre-op and 1 (+/- 7) post-op (p<0.002). Median functional score increased from 7 to 8 post-operatively (p= 0.03).

Conclusão

SPC completely controls or significantly reduces the frequency of DA and GMS. Such results are in line with an apparent reset of the electrical equilibrium of the brain, manifested by dramatic reduction of synchronic bilateral epileptiform discharges.

Palavras-chave

Epilepsy surgery; Selective posterior callosotomy; Drop attacks;