Safety and efficacy of Gamma Knife radiosurgery in hypothalamic hamartomas with severe epilepsies: A prospective trial in 48 patients and review of the literature.

Epilepsies associated with hypothalamic hamartomas (HHs) are frequently drug resistant with severe psychiatric and cognitive comorbidities. We performed a prospective trial to evaluate the safety and efficacy of Gamma Knife radiosurgery (GKS). Between October 1999 and October 2007, a total of 57 patients were investigated, included and treated by GKS in Timone University Hospital. Preoperative workup and 3-year postoperative evaluation consisted of seizure diary, neuropsychological, psychiatric, endocrinologic, visual field, and visual acuity examinations. Follow-up of >3 years was available for 48 patients. Topologic type was type I in 11 patients, type II in 15, type III in 17, type IV in one, type V in one, type VI in one, and mixed type in 2. The median marginal dose was 17 Gy (min 14 and max 25 Gy). The median target volume was 398 mm3 (28-1,600 mm3 ). Due to partial results, 28 patients (58.3%) required a second treatment. The median follow-up was 71 months (36-153 months). At last follow-up, the rate of Engel class I outcome was 39.6%, Engel class II was 29.2% (I+II 68.8%), and Engel class III was 20%. Global psychiatric comorbidity was considered cured in 28%, improved in 56%, stable in 8%, and continued to worsen in 8%. No permanent neurologic side effect was reported (in particular, no memory deficit). Nondisabling transient poikilothermia was observed in three patients (6.2%). A transient increase of seizure frequency was reported in 8 patients (16.6%) with a median duration of 30 days (9-90 days). Microsurgery was proposed because of insufficient efficacy of GKS in seven patients (14.5%) with a postoperative Engel class I-II in 28.6%. This prospective trial demonstrates very good long-term safety and efficacy of GKS for 2 patients. Beyond seizure reduction, the improvement of psychiatric and cognitive comorbidities along with better school performance and social functioning, being better socially integrated, having friends having a social life, working, participating to group activities turn out to be major benefits of GKS in this group of patients with frequently catastrophic epilepsy.