Efficacy of interstitial radiosurgery in the treatment of pharmacoresistant gelastic epilepsy due to hypothalamic hamartomas

Rationale: Gelastic epilepsies are often pharmacoresistant and show a severe course with development of tonic, complex-partial and secondarily generalized tonic-clonic seizures. This case series reports children and juvenile patients treated by interstitial radiosurgery. Patients and methods: 15 patients aged 3–20 years (mean: 13.9 y) with hypothalamic hamartomas and gelastic epilepsy were treated stereotactically using 132I-seeds; 8 of them were treated repeatedly. Outcome analysis was performed according to the Engel classification at follow-up periods of 3–36 months. Results: After a mean follow-up time of 22.7 months, 20% of patients were completely seizure free at last follow-up (Engel Ia), another 20% had only auras/simple partial seizures left (Engel Ib). 13% had a seizure reduction by more than 90% (Engel II), and another 20% by 75% (Engel III). 27% did not show a relevant decrease in seizure frequency (Engel IV). As a relevant side effect of treatment, one patient had a weight gain of 20kg, other hormonal disturbances did not occur. In some patients, an improvement in behavior accompanied the positive treatment effect. Conclusion: 73% of patients treated had a significant reduction of seizure frequency, 40% became either completely seizure free or had simple partial seizures only. The latter group gained significantly in their everyday life quality, whereas even with major reduction in seizure frequency often relevant impairments remained due to epileptic seizures. Considering the low rate of complications, stereotactic treatment by interstitial radiosurgery is an interesting option in this difficult-to-treat epilepsy type.