Abstracts

RATIONALE: Hypothalamic hamartomas can be associated with precocious puberty and gelastic epilepsy. Over the past several years, the syndrome of and hypothalamic hamartoma and gelastic seizures (HHGS) has been refined by a number of investigators. Most characteristically, patients with HHGS syndrome present with gelastic seizures early in life followed by a progressive epileptic syndrome most typically with multifocal seizures or a secondary generalized epileptic encephalopathy. Resistance to antiepileptic drugs, ketogenic diet and other nonsurgical treatments is common.
Because of the high morbidity associated with traditional procedures, we have developed a minimally invasive surgical approach to these patients with relatively low morbidity and good results.
METHODS: Twelve patients with hypothalamic hamartomas and intractable seizures were evaluated and received surgery at the UAB Epilepsy Center. Presurgical evaluation included routine EEG, extended EEG video monitoring with scalp and sphenoidal electrodes and neuropsychological studies, MRI and ictal/interictal SPECT studies.
Patients 1-8 underwent stereotactic depth EEG electrode implantation studies and subsequently underwent radio-frequency lesioning. Patients 9-12 underwent endoscopic surgical approach with acute intraoperative depth EEG followed by radio-frequency and resection. For the first eight patients, the procedure consisted of a two-stage investigation. In Stage I, a stereotactic frame-based MRI was obtained, and under sedation stereotactic electrode placement was performed through the frontal approach into the hamartoma. Prolonged EEG video monitoring was obtained until seizures were recorded. During Stage II, a stereotactic MRI frame was again placed under mild sedation. A stereotactic radiofrequency thermocoagulation probe was placed using the same coordinates of the depth electrode placement. Following stimulation, stereotactic thermocoagulation was carried out by heating the probe to 80 F for one minute. The probe and frame were then removed, and the patient was taken to the NICU for recovery.
Postoperative follow up was obtained at one month and thereafter every three months. Medication adjustments were done according to the patient[ssquote]s clinical status.
RESULTS: Patients 1-8 received stereotactic radiofrequency lesioning preceded by chronic depth electrode recordings. At the time of followup (mean 33 months), three patients were in Class 1, two patients were in each Class 2 and 3, and one patient was in Class 4. Complications in this group included transient third-nerve palsy in patient 7.
Four patients underwent endoscopic visualization of the hamartoma with a combination of both radio frequency and partial resection. Two patients are Class 1, one patient is Class 2, and one patient is Class 3. Complications included brain stem infarction and transient memory loss in one patient. Overall, eight patients (67%) were either Class 1 or 2 with the remaining patients (33%) Class 3 or 4.
Major improvements in social disposition have been reported by the families. No endocrinologic abnormalities were observed longterm.
CONCLUSIONS: Endoscopic and sterotactic thermocoagulation are safe and effective in the surgical management of HHGE syndrome. For large lesions, the endoscopic approach has advantages since it permits visualization.