Clinical features of unilateral multilobar and hemispheric polymicrogyria (PMG)‐related epilepsy and seizure outcome with different treatment options

Abstract Objective To provide evidence for choosing surgical or nonsurgical treatment for epilepsy in patients with unilateral multilobar and hemispheric polymicrogyria (PMG). Methods We searched published studies until September 2022 related to unilateral multilobar and hemispheric PMG and included patients who were followed up at the Pediatric Epilepsy Centre of Peking University First Hospital in the past 10 years. We summarized the clinical characteristics and compared the long‐term outcomes after surgical or nonsurgical (anti‐seizure medications, ASMs) treatment. Results A total of 70 patients (49 surgical, 21 non‐surgical) with unilateral multilobar and hemispheric PMG were included. The median age at epilepsy onset was 2.5 years (1.0–4.1). The most common seizure types were focal and atypical absence seizures. In the whole cohort, 87.3% had hemiparesis and 67.1% had electrical status epilepticus during slow sleep (ESES). There were significant differences in age at epilepsy onset, extent of lesion, and EEG interictal discharges between the two groups. At the last follow‐up (median 14.1 years), the rates of seizure‐freedom (81.6% vs. 57.1%, p = 0.032) and ASM discontinuation (44.4% vs. 6.3%, p = 0.006) were higher in the surgical group than in the nonsurgical group. Patients in the surgical group had a higher rate of seizure‐freedom with complete resection/disconnection than with subtotal resection (87.5% vs. 55.6%, p = 0.078), but with no statistically significant difference. In the nonsurgical group, more extensive lesions were associated with worse seizure outcomes. Cognition improved postoperatively in 90% of surgical patients. Significance In patients with unilateral multilobar and hemispheric PMG, the age of seizure onset, the extent of the lesion and EEG features can help determine whether surgery should be performed early. Additionally, surgery could be more favorable for achieving seizure freedom and cognitive improvement sooner. Plain Language Summary We aim to summarize clinical characteristics and compare the long‐term outcomes after surgical and nonsurgical (ASM) treatment to provide a basis for treatment decisions for patients with unilateral multilobar and hemispheric polymicrogyria (PMG)‐related epilepsy. We found that patients with unilateral hemispheric and multilobar PMG had significantly higher rates of seizure freedom and ASM discontinuation with surgical treatment than with nonsurgical treatment. In the surgical group, seizure outcomes were better in patients treated with complete resection/disconnection than in those treated with subtotal resection, but the difference was not statistically significant.