Abstract
OBJECTIVE: To analyze the residual post-resection electrocorticography (ECoG) status and the related risk factors in patients with medically intractable epilepsy (MIE). METHODS: A retrospective analysis was conducted to cover 146 MIE patients who underwent craniotomy for surgical resection in the department of Neurosurgery, Second Affiliated Hospital of Chengdu Medical College between January 2006 and January 2018. The patients were divided into a non-residual group ( n=54) and a residual group ( n=92) according to their ECoG results after the first resection surgery. Then, the 92 patients in the residual group underwent additional palliative surgery and they were further divided into an improvement subgroup ( n=50) and a non-improvement subgroup ( n=42), according to the reevaluation results of improvements in their postoperative ECoG. The differences in the mean annual seizure-free rate among the groups were compared. Univariate and multivariate logistic regression analysis was conducted to analyze the risk factors of residual post-resection ECoG. RESULTS: During the ten-year follow-up after the operation, the mean annual seizure-free rate was 86.7% in the non-residual group and 57.1% in the residual group, showing significant difference between the two groups ( P<0.001). In the subgroups, the mean annual seizure-free rate was 71% in the improvement subgroup and 46.5% in the non-improved subgroup, showing significant difference between the two subgroups ( P=0.003). Logistic regression showed that risk factors associated with residual post-resection ECoG included being female, patient age at the time of surgery being over 18, multi-lobe epilepsy, functional area involvement, and negative MRI findings ( P<0.05). Analysis of the subgroups showed that multi-lobe epilepsy and functional area involvement were risk factors related to not showing improvements in post-resection ECoG ( P<0.05). CONCLUSIONS: Findings based on the status of residual post-resection ECoG have shown that patients without residual post-resection ECoG had the best treatment outcomes, and patients who had residual post-resection ECoG, but showed significant improvement after palliative surgery had the second best treatment outcomes. Patients who were female, who had their surgeries when they were older than 18, and who had multi-lobe epilepsy, functional area involvement, or negative MRI results were more likely to have residual post-resection ECoG. Among patients with residual post-resection ECoG, those with multi-lobe epilepsy and functional area involvement showed little improvement in residual post-resection ECoG even after undergoing additional palliative surgery.