Endoscopic resection of hypothalamic hamartoma for refractory epilepsy: preliminary report

The intrahypothalamic subtype of hypothalamic hamartoma (HH) is usually associated with refractory epilepsy, cognitive impairment, and organic behavioral disturbance. It is often a devastating disorder for both patient and family. The gelastic (laughing) seizure is the hallmark seizure type. However, multiple other seizure types can often develop during the course of the disease, and are typically refractory to antiepilepsy drugs (AEDs). Previously it was uncertain if HH tissue was responsible for seizure genesis or whether resection of the HH would result in improvement of the seizures. Recently both of these questions have been answered in the affirmative. Surgical resection using a transcallosal, interforniceal approach has recently been shown to be efficacious and generally safe for the treatment of the refractory seizures. However, even more recently, we have been performing the majority of HH surgical resection by using an endoscopic technique with a transventricular approach. This article presents the details of the operative technique and discusses preliminary outcome data, particularly with comparison to the transcallosal technique. Using an endoscope holder with micromanipulator facilitates endoscopic resection. Linking the endoscope to a system of frameless stereotaxis is essential for successful resection. Forty-four patients age 8 months to 44 years have undergone endoscopic resection. The ideal candidate for endoscopic removal has a hamartoma completely or nearly completely involving one wall of the third ventricle and is 1 cm or less in greatest diameter. Because it is essential to be able to visualize the lesion within the third ventricle for resection, there must be at least 6 mm of space between the top of the lesion and the roof of the third ventricle. Patients with intractable epilepsy caused by HH can be rendered seizure free or show marked improvement in seizure frequency by surgical removal, surgical disconnection, or radiosurgical ablation of the lesion. Which of these options should be recommended for an individual patient is not yet clear. One of the options involves resection or disconnection of the HH with a transventricular endoscopic approach. In selected patients, endoscopic resection of HH is effective in the treatment of intractable epilepsy, with lower complication rates and shorter hospital stays than transcallosal resection.