Significance of the electrophysiological border between hypothalamic hamartomas and the hypothalamus for the target of ablation surgery identified by intraoperative semimicrorecording

Abstract

Objective: Ablation surgery has become the first line of treatment for hypothalamic hamartomas (HHs). For effective treatment, optimum targeting of ablation is mandatory. The present study aimed to evaluate the correspondence between the electrophysiological features of HHs and morphological targeting by semimicrorecording during stereotactic radiofrequency thermocoagulation (SRT). Methods: Eighty HH patients who underwent SRT were involved. Semimicrorecording was performed on the first trajectory. The distance from the center of the target at the morphological border (TMB) determined by magnetic resonance imaging, differences in discharge patterns, and area potentials (APs) were measured. Results: The electrophysiological border (EB) between the HH and hypothalamus was detected by semimicrorecording in 73 (91.3%), AP increase (API) in the HH was detected in 31 (38.8%), and spike discharges (SDs) of the HH were detected in 56 patients (70.0%). Semimicrorecording showed significantly different APs among structures passing through the trajectory, except between API and SDs. The median distances from the center of the TMB to the EB, API, SDs, and AP decline were −3.50, −2.49, −1.38, and +2.00 mm, respectively. Significance: The electrophysiological features of HHs were shown by semimicrorecording during SRT. The EB corresponded to the morphological border. The electrophysiologically active area of HHs was located near the border. Ablation surgery should focus on disconnection at the border between the HH and the hypothalamus to maximize its effectiveness, as well as to reduce complications.

Minimally invasive procedures for hypothalamic hamartoma–related epilepsy: a systematic review and meta-analysis

“…18,19 Studies by Sonoda et al 20 and Hamdi et al 21 were also excluded since they reported cognitive results rather than epilepsy outcomes after HH treatment. Four articles [22][23][24][25] were excluded because of duplicated data with the study by Shirozu et al 26 Only 7 patients from Abla et al 27 and 6 from Mathieu et al 28 were included because other procedures were performed during the follow-up period. A patient from the study by Du et al 29 was excluded because of the absence of seizures at HH presentation.…”

Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Hypothalamic Hamartoma: Surgical Approach and Treatment Outcomes

“…The T2-STIR sequence was used to discriminate the white matter fibers from the HH body in this planning protocol. The primary goal of this procedure was full disconnection between the lesion and normal brain tissue [ 12 ].…”

“…Postoperative enhanced T1 images obtained immediately after the ablation (repetition time (TR) = 2300 ms, echo time (TE) = 2.3 ms, slice thickness = 1 mm, voxel size = 1 mm × 1 mm × 1 mm) and preoperative MRI scans were fused to construct a 3D model of the actual ablation area, with the ablation rate being defined by the percent of HH body ablated. A 3D model of the connected region was also generated as follows: Initially, T1 images were rotated around to Z-axis to ensure that the HH border was parallel to the X-axis, with this border being defined by the intensity or angle differences of the third ventricle wall [ 12 ]. Then, three consecutive slices from the border to the HH body were selected and used to outline the edges of the connected part, thereby yielding a 3D model.…”

Hypothalamic Hamartomas

“… 53 , 54 The unique electrophysiologic characteristics of both the HH and the nearby normal hypothalamus were also studied, and those findings potentially correlated with the area to be resected/disconnected. 55 …”