Rationale: Despite the proven superiority of epilepsy surgery to medical or dietary therapies in the treatment of
refractory focal epilepsy, it remains one of the most
underutilized procedures in epilepsy. This
underutilization is greater in patients who failed initial surgery. This case series examined the clinical characteristic, reasons for initial surgery failure, and outcomes in a cohort patients who underwent hemispherectomy following unsuccessful, smaller resections for intractable epilepsy (sub-hemispheric group; SHG) and compared to those of a cohort of patients who underwent hemispherectomy as the first surgery (hemispheric group; HG)._x000D_
Methods: Patients who underwent hemispherectomy at Seattle Children’s Hospital from 1996 – 2020 were identified. Inclusion criteria for SHG were: 1) patients less than 18 years of age at the time of hemispheric surgery, 2) initial sub-hemispheric, resective epilepsy surgery that did not produce seizure freedom, 3) hemispherectomy or hemispherotomy after the limited surgery and 4) follow up for at least 12 months after hemispheric surgery. Data collected included patient demographics, seizure etiology, seizure semiology, comorbidities, prior neurosurgeries, neurophysiologic studies, imaging studies, surgical details, surgical outcomes, seizure outcomes, and functional outcomes. Seizure etiology was classified as: (1) developmental (malformations of cortical development, hemimegaloencephaly), (2) acquired (stroke, brain tumor, gliosis), (3) progressive (Rasmussen encephalitis, Sturge-Weber Syndrome). We compared SHG to HG in terms of demographics, seizure etiology, seizure and neuropsychological outcomes.
Results: There were
14 patients in the SHG and 51 patients in the HG. Baseline patient characteristics are described in Table 1. All SHG patients had Engel IV after their initial resective surgery. Overall, 86% (n=12) of SHG patients had excellent post-hemispherectomy seizure outcomes (Engel I, II). All SHG patients with progressive etiology (n=3) had favorable seizure outcomes with eventual hemispherectomy (Engel I, n=1; Engel II, n=1; Engel III, n=1). There was no statistical difference in Engel classification post hemispherectomy between the groups (p=0.35). There were no statistical differences in both post-surgical Vineland Adaptive Behavior Scales Adaptive Behavior Composite scores and post-surgical full scale intelligence scores between groups when accounting for pre-surgical scores.
Conclusions: Hemispherectomy as a repeat surgery after a failed, limited, sub hemispheric epilepsy surgery has favorable seizure outcome with stable or improved intelligence and adaptive functioning. Findings are similar to those who had hemispherectomy as first surgery. This can be explained by the relatively small number of patients in SHG and the higher likelihood of hemispheric surgeries to resect or disconnect the entire epileptogenic lesion compared to smaller resections. Prospective, multi-center, long-term studies are needed to further evaluate the seizure and functional outcomes of hemispheric surgeries.
Funding: None