Abstracts

Rationale: Hypothalamic Hamartoma (HH) is accompanied by a characteristic syndrome which consisted of medically intractable gelastic seizure (GS), various type of seizures due to secondary epileptogenesis, and behavioral and cognitive problem due to epileptic encephalopathy. As HH has an intrinsic epileptogenicity, surgical treatments (disconnection) provide not only cure of seizures but also improvement of behavioral and cognitive function. Although there are various surgical procedures, we have consecutively performed the stereotactic radiofrequency thermocoagulation (SRT) for the treatment of HH since 1997. The aim of this study is to validate the effectiveness and safety of SRT and re-SRT in patients with HH. Methods: We retrospectively reviewed 150 patients (93 males and 57 females; median age at the first SRT, 8, range 1.7–50 years) who underwent SRT in our single center. We evaluated clinical features, profiles of surgical procedures, surgical outcomes, and complications. Results: All patients had GS, and 121 had other types of seizure (non-GS). The median diameter of HH was 15 (range, 4.5–80) mm. HH subtypes (Kameyama’s classification, 2009) included intrahypothalamic type (n=35, 23.8%), mixed-type (104, 70.7%), and parahypothalamic type (8, 5.4%). A total of 206 SRTs were performed, namely 43 patients (20.9%) require two (33), three (7), and four SRTs (3) for recurrent or residual GS. In 148 patients with more than 1-year follow-up after last SRT, 132 patients (89.2%) achieved freedom from GS after first (102), second (26), third (2), and fourth SRT (2). 88 (72.7%) of 121 patients achieved freedom from non-GS after first SRT, but re-SRTs did not show further effectiveness.154 SRTs (74.8%) were accompanied by transient complications which improved within two weeks after surgery. These included hyponatremia (63, 62.5%), hyperphagia (58, 28.2%), high fever (54, 26.2%), short memory disturbance (19, 19.2%). The incidence of transient complications did not increase in re-SRT (62.5%) compared with first SRT (79.3%).Prolonged disabling complications were recognized in five cases (3.3%) who presented prolonged consciousness disturbance lasting three months (2), short memory disturbance (2), and mild hemiparesis (1). Endocrinological deficiency required supplementation was seen in five cases (two of them were diagnosed as Pallister-Hall syndrome). Weight gains were found in 24 patients (11.7%) including five cases with abnormal obesity.In consideration of clinical factors for recurrence of seizures, the size and shape of HH or the surgical procedures (numbers of trajectories and coagulated site) was not statistically significant factors. Lower ages at surgery and at seizure onset affected the recurrence of GS with statistically significance (p Conclusions: SRT achieved favorable seizure outcomes for the patients with HH, and was also applicable for recurrence of GS. In contrast, recurrent non-GS was intractable even by re-SRT. Longer duration may cause the independent secondary epileptogenesis resulting in refractory non-GS. Early indication of HH is desirable for better overall seizure outcome. Funding: No funding.