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This tool estimates the risk of seizure recurrence and Chance of an Occurrence of a Seizure in the next Year (COSY) following frontal lobectomy surgery for refractory frontal lobe epilepsy.

Variables Used:

Frontal Lobectomy Surgery:

• This variable indicates whether a patient underwent a frontal lobectomy (Yes/No). Outcomes were analyzed for patients with refractory frontal lobe epilepsy, focusing on long-term postoperative seizure freedom and recurrence dynamics.

Further Variables Not Included in the Prediction Model:

Several critical factors influence surgical outcomes, though they are not directly integrated into this tool:

• Imaging Predictors: Favorable outcomes were strongly associated with identifiable frontal lesions on preoperative magnetic resonance imaging (MRI). Patients with abnormal frontal lobe findings had significantly better outcomes compared to those with normal MRIs (P = 0.027).

• Pathological Subgroups: Histopathological findings such as tumors (e.g., oligodendrogliomas, gangliogliomas) and malformations of cortical development (MCDs) were significant factors. Tumor-related etiologies were associated with better outcomes (62% seizure freedom at follow-up) than MCDs (52%).

• Extent of Surgery and Intraoperative Monitoring: Complete resection of the epileptogenic zone (e.g., gross total resection or lobectomy) and intraoperative electrocorticography positively impacted outcomes, improving seizure freedom rates.

• Electrophysiologic Predictors: Favorable outcomes correlated with localized ictal patterns and frontal rhythms on electroencephalography (EEG), while generalized or non-localized discharges were linked to poorer outcomes.

• Acute Postoperative Seizures (APOS): APOS, defined as seizures occurring within the first postoperative week, were predictive of poorer long-term seizure control (P < 0.0001).

Outputs:

Risk of Seizure Recurrence:

• This output provides an individualized, dynamic estimate of seizure recurrence over time following surgery. For instance, the estimated probability of seizure freedom was 57.3% at 1 year, 51.2% at 2 years, and 50.0% at 5 years postoperatively.

COSY (Change of Seizure in the Next Year):

• COSY predicts the likelihood of a seizure occurring in the next year following surgery.