[Indications and risk of neurosurgical techniques in the adult presenting with drug-resistant partial epilepsy (radiosurgery included)]

Abstract

To be considered for resective (curative) surgery, most seizures have to been proved to arise exclusively from one area of the brain that is functionally silent. The drug-resistance must be certain, and the patient must be strongly motivated to undergo surgery. Temporal lobectomy for drug-resistant temporo-mesial epilepsy is now scientifically validated by a randomized controlled trial. Hemispherotomy, which consists in complete disconnection of one hemisphere, is a curative technique, which may be considered where there is a pre-existing hemiplegia associated with a structural abnormality of the contralateral hemisphere. Therefore, it is rarely performed in adult patients. Stereotactic radiosurgery is also a curative technique, which shares most of its indications with those of temporo-mesial resections. Callosotomy is a palliative technique, which consists in disconnecting the hemispheres, one from the other. It may be considered in individuals having frequent atonic seizures (drop attacks). Multiple subpial transection involves transection of transverse fibers, leaving longitudinal fibers intact. It may be performed if the epileptogenic focus is located in an eloquent brain area. The complication rate of resective surgery is low. Controlateral motor impairement is the main permanent complication related to cortical resection. It is a rare occurrence (1 to 2 percent of cases) due to peroperative lesions of the sylvian vasculature, or of the anterior choroidal artery, or even of the motor area. Postoperative hematomas, infections, or hydrocephalus may also occur in 2 to 6 percent of cases, depending on the authors. Some postoperative neuropsychological complications are reported in the literature, especially after surgery on the dominant side. Hydrocephalus and infection are the most frequent complications occurring after hemispherotomy (10 percent of cases). Dysconnexion syndrome is a rare complication, which can be seen after total callosotomy. It is unusual for the effects of disconnection after anterior callosotomy to represent significant handicap. Permanent postoperative worsening of a pre-existing neurological impairement, as well as hematomas, are seen in less than 10 percent of the cases after multiple subpial transection. In conclusion, surgery is an important therapeutic option, which has to be considered as soon as the epileptic disease appears to be drug-resistant, particularly in case of temporo-mesial epilepsy.