Efficacy and safety of radiosurgical callosotomy: a retrospective analysis.

PURPOSE: Anterior callosotomy is a surgical option for the treatment of generalized tonic or atonic seizures associated with drop attacks. Besides open surgery, a radiosurgical callosal disconnection using the gamma knife (GK) also can be performed, but reliable data about tolerability and efficacy are sparse. METHODS: Eight patients (three female, five male age range, 5 to 69 years) with severe generalized epilepsy associated with disabling drop attacks underwent GK callosotomy between 1993 and 2004. In six patients, the anterior third of the corpus callosum was radiosurgically disconnected. In one patient a second procedure with GK treatment of the middle third of the corpus callosum was added 17 months later. In two patients posterior GK callosotomy had followed partial hemispherotomy. RESULTS: Drop attacks (DAs) were completely abolished in three patients, and two patients had a marked DA seizure reduction of 60%. Two of four patients with additional generalized tonic-clonic seizures showed a reduction of 100%, and the remaining, a 50% and 60% decrease, respectively. Other seizure types responded less well to the radiosurgical treatment. In both patients with posterior GK callosotomy after hemispherotomy, partial seizures decreased. Beside transient headache in two patients, no immediate or long-term postradiosurgical side effects were observed. CONCLUSIONS: Palliative radiosurgical callosotomy is an efficient and safe noninvasive alternative to the open procedure with comparable results. No signs of postradiosurgical side effects were noted within an up to 12-year posttreatment period.

No effect of immunomodulatory therapy in focal epilepsy with positive glutamate receptor type 3--antibodies.

Antibodies against the glutamate receptor type 3-(GluR3) have been found in association with Rasmussen's encephalitis (RE) but were also detected in patients with non-inflammatory focal epilepsies. We report the case of an 18-year-old patient with treatment refractory left mesial temporal lobe epilepsy accompanied by high levels of GluR3 antibodies. Different from experiences in patients with RE immunomodulatory therapy by use of intravenous gammaglobulines neither altered GluR3 serum levels nor had any effect on seizure frequency in our patient. Interestingly, GluR3 serum levels remained positive after successful surgical intervention leading to patient's seizure freedom.