Authors :
Presenting Author: Yutaro Takayama, MD.,PhD. – Yokohama City University
Yuiko Kimura, MD.,PhD. – Neurosurgery – National Center Hospital of Neurology and Psychiatry; Keiya iijima, MD.,PhD. – Neurosurgery – National Center Hospital of Neurology and Psychiatry; Kenzo Kosugi, MD.,PhD. – Neurosurgery – National Center Hospital of Neurology and Psychiatry; Munetake Yoshitomi, MD.,PhD. – Neurosurgery – National Center Hospital of Neurology and Psychiatry; Tetsuya Yamamoto, MD.,PhD. – Neurosurgery – Yokohama City University; Masaki Iwasaki, MD.,PhD. – Neurosurgery – National Center Hospital of Neurology and Psychiatry
Rationale:
Stereotactic ablation techniques such as radiofrequency thermocoagulation (RFTC) and laser interstitial thermal therapy (LITT) based on the results of stereoelectroencephalography (SEEG) are attracted as minimally invasive surgery for refractory epilepsy with a deep-located lesion. LITT is increasingly used in the U.S., while RFTC is expected to play an alternative role in situations where LITT is not available. Stereotactic ablation has been suggested to be less effective in terms of seizure control than resective surgery. However, especially for the areas that are difficult to approach with craniotomy such as the insulo-opercular region, RFTC can be the first option and the treatment is planned to target the entire epileptogenic zone to maximize the chance of seizure freedom.
Methods:
We report our early experiences of five pediatric patients (three boys and two girls) with intractable epilepsy with insulo-opercular regions who underwent the RFTC separately planned after SEEG in 2021 through 2022, with a postoperative observation period of more than 100 days. Results:
Median age at surgery was five (2-11) years, and median postoperative follow-up was 462 (188-722) days. All patients had daily bilateral tonic seizures, MRI abnormalities, and hypometabolism on FDG-PET in the insulo-opercular area. RFTC was performed with the Leksell stereotactic frame after planning to target the entire epileptogenic zone with multiple 5-mm sphere coagulation models. The median number of trajectories was 13 (6-14) and the median number of coagulated lesions was 31 (20-48). The median coagulation efficiency, which represents the ratio of treatment volume to target volume, was 70.2% (40.8-91.7%). All patients obtained seizure freedom at 100 days after RFTC, and three patients remained seizure-free at the last follow-up. cases with recurrent seizures tended to show a wide range of hypometabolism, and coagulation efficiency also tended to be low. No permanent neurological complications occurred after RFTC.
Conclusions:
RFTC may be expected as an alternative option for refractory insulo-opercular epilepsy because the method is less invasive than conventional craniotomy and can provide a favorable chance of seizure freedom. Careful planning is essential since an increase in the number of RFTC trajectories and coagulation lesions can lead to complications. Further experience will be needed to make this technique more sophisticated.Funding:
This study was supported, in part, by Grants-in-Aid for Scientific Research (KAKENHI) Grant No. JP19K09494 from the Japan Society for the Promotion of Science (JSPS), the Japan Agency for Medical Research and Development (AMED) under Grant Nos. JP20ek0109374 and JP20ck0106534, and Intramural Research Grant (1-4: Integrative research on pathomechanism, diagnostic methodology and therapeutics for epilepsy) for Neurological and Psychiatric Disorders of the National Center of Neurology and Psychiatry.