Authors :
Presenting Author: Zachary Bernstein, BS – Emory University School of Medicine
Katherine Chandler, BS – Emory University School of Medicine
Joshua Chern, MD, PhD – Children's Healthcare of Atlanta
Nealen Laxpati, MD, PhD – Emory University School of Medicine
Moira Black, MD – Emory University School of Medicine, Children's Healthcare of Atlanta
Jenny Lin, MD – Children's Healthcare of Atlanta
Sonam Bhalla, MD – Emory University School of Medicine, Children's Healthcare of Atlanta
Guojun Zhang, MD – Emory University School of Medicine, Children's Healthcare of Atlanta
Neal Sankhla, MD – Emory University School of Medicine, Children's Healthcare of Atlanta
Hyoung Choi, MD – Emory University School of Medicine, Children's Healthcare of Atlanta
Donald Bearden, PhD, APBB-CN – Emory University/CHOA
Rationale:
Radiofrequency ablation (RFA) via stereoelectroencephalography (SEEG) is indicated when epileptogenic zone (EZ) overlaps with eloquent cortex and there is concern for functional loss due to surgery. While RFA is often effective, there exists no evidence-based standard for pediatric RFA procedure parameters, including optimal amount of energy administered and ablation time. It is unknown how these RFA variables influence the resulting lesion size seen on magnetic resonance imaging (MRI). Furthermore, the association between these variables and post-procedural changes in neuropsychological and sensorimotor function and seizure burden is not well characterized.
Methods:
Medical records of 16 patients (9 males, Mage = 16.9, SD = 3.38 years) with drug-resistant epilepsy treated with SEEG-guided RFA at Children’s Healthcare of Atlanta (CHOA) from 2022 to 2024 were reviewed. Demographic and clinical data were collected, including energy (watts) and time (minutes) of RFA. Outcome data included patients’ post-RFA a) neuropsychological function, b) sensorimotor function, c) radiographical RFA lesion size (volume), and d) seizure burden. Outcome data was collected at the first neurosurgical follow-up appointment following RFA. The first T2 MRI images acquired after RFA were analyzed. Lesion volume was computed as (4/3)πr3 if the lesion was spherical and as (4/3)πabc if the lesion was ellipsoid, where a, b, and c are radii of the ellipsoid in axial, coronal, and sagittal planes, respectively. Descriptive statistics were conducted, as well as multiple linear regression to evaluate the relationship between RFA energy, time, and energy*time with lesion size.
Results:
Across study patients, there was a cumulative total of 41 RFA locations. Patients had an average of 2.6 RFA locations (SD = 1.3, range = 1-5). Two patients (12.5%) had neuropsychological changes and 3 (18.75%) patients had sensorimotor changes following RFA. Eight (50%) patients experienced seizure freedom and no patients experienced increased seizure burden following RFA. The mean energy and time of RFA was 2.9 watts and 2.1 minutes, respectively. Multiple linear regression was limited to 8 patients with complete data, which was not statistically significant (F(3, 17) = 0.431, p = 0.734). The model had an R-squared value of 0.071, and an adjusted R-squared of -0.093.
Conclusions:
Qualitative results from this small, retrospective study suggest that RFA reduces seizure burden and causes neuropsychological and/or sensorimotor changes in a minority of patients with drug-resistant epilepsy. However, statistical analyses did not reveal significant effects of RFA energy, time, or energy*time on lesion size, perhaps due to the lack of power associated with the study’s limited sample size or the limitation of the MRI in detecting size differences for small lesions. Prospective studies with larger sample sizes are needed to evaluate the effectiveness of RFA on functional and seizure outcomes in pediatric patients with drug-resistant epilepsy.
Funding:
This study is funded by the Georgia CTSA TL1 program; TL1TR002382.