Treatment options for gelastic epilepsy due to hypothalamic hamartoma: interstitial radiosurgery.

Surgical treatment of hypothalamic hamartomas (HHs) as the underlying etiology of gelastic epilepsy is associated with a high risk of complications because of the close vicinity of adjacent structures such as the optic tracts and mammillary bodies. Treatment with interstitial radiosurgery uses stereotactically implanted (125)I seeds emitting gamma radiation from the center of the lesion, with a steep spatial gradient, over a period of about 3 weeks. This form of HH therapy offers particular advantages regarding the risk for major side effects. In a series of 15 children and adolescents treated in Freiburg, Germany, 53% of patients achieved significant improvement in seizure frequency (Engel class I or II outcome). Transient side effects were related to the development of local edema, resulting in headache and mental slowing. A persistent weight gain was noted in 3 patients, which was severe in 1 (20 kg). There were no other neurologic, neuropsychologic, or neuropsychiatric side effects, which compares favorably with most surgical series.