Controle de crises de queda (Drop Attacks) com calosotomia posterior seletiva : resultados e dados anátomo-radiológicos e prognósticos

Abstract

In the Porto Alegre Epilepsy Surgery Program (PCE) of the HSL PUCRS, patients candidates for posterior selective calosotomy represent about 5% of the so-called "surgical" cases. However, these patients usually present severe refractory generalized epilepsies with drop attacks, which are particularly important because they lead to unexpected falls and risk of serious injury and death from severe cranial trauma. This catastrophic picture does not allow the patient and his / her relatives to live a normal life. The threat of an imminent unexpected fall keeps all involved in the patient's daily care permanently alert. The corpus callosum is the largest commissural fiber bundle in the brain and callosotomy, in its different variations and extensions, has the objective of prevent propagation and synchronization of epileptogenic discharges between the cerebral hemispheres and, therefore, to reduce or stop drop attacks. Callosotomy is a palliative treatment, indicated for patients with generalized epileptic seizures with drop attacks, who are not candidates for resective surgery and have secondary bissynchronic discharges in the electroencephalogram (EEG), regardless of the etiology of epilepsy. The objectives of this study are to present the surgical results (drop attacks control) of patients who had selective posterior calosotomy and to define correlation factors with the result, thus refining the surgical indication. Another objective is to define the necessary extension of corpus callosum resection for a satisfactory control of drop attacks. Surgical outcomes and demographic characteristics in 51 patients were analyzed. Twenty seven patients had post-operative magnetic nuclear resonance (MRI) and 18 tractogtraphy to correlate the extent and nature of the resected fibers with surgical results. We also correlated the demographic characteristics (age and duration of epilepsy in surgery, age at seizure onset and etiology) with surgical results. Selective posterior callosotomy was effective in controlling atonic falls with an overall 89, 3% decrease in drop attacks frequency (p <0.001). Younger patients and with shorter duration of epilepsy at surgery are significantly more likely to achieve a more favorable outcome (p <0.001). The extent of resection of the posterior corpus callosum was not correlated with surgical outcome (r-0.02), however, the fibers connecting the primary and supplementary caudal motor areas were resected in all patients. Finally, in postoperative tractography, the presence of residual fibers interconnecting homologous pre-motor and rostral supplementary motor areas does not seem to correlate with control of atonic falls.