Abstracts

Many epileptologists advocate early surgical treatment of refractory epilepsy in children and young adults. This study was performed to determine if there is a relationship between epilepsy duration prior to epilepsy surgery and successful surgical outcomes in patients with childhood-onset epilepsy. We performed secondary data analysis of a tertiary care epilepsy surgery database selecting for patients with onset of epilepsy [lt] 18 years old and with their first resective epilepsy surgery. Outcomes at one or more years after surgery were classified as good if the patient was rated Engel Class (EC) 1and poor if rated EC 2-4. Predictors included race, sex, age at onset of epilepsy, age at time of surgery, duration of epilepsy prior to surgery, IQ prior to surgery, MRI findings, bilateral or unilateral MRI findings, Pathology, and Diagnosis. Diagnosis was determined by review of the mri and pathology reports by raters who were blinded to the surgical outcome. 188 patients met criteria for inclusion and had sufficient information for analysis. Mean age at onset 7.46 +/- 5.73 y. Mean age at surgery 30 +/- 11 y.iagnoses were MTS (60%), cortical malformation (8.5%), tumor (4.2%), and gliosis (7.4%). Patients with cortical malformation, tumor or vascular malformation had a median duration of 13 years. Patients with MTS or gliosis had a median duration of 25 years. If data for patients with one year post surgical followup was analyzed utilizing chi-square analysis, unilateral mri abnormalities were predictive of good outcome (p=0.035). Duration, age at onset, and age at surgery were divided into quartiles for analysis. If only the diagnosis MTS was analyzed, the oldest quartile of age at surgery (40-61y) was associated with poorer outcomes (p=0.034). Cox survival analysis of time to EC3 for patients with longer follow-up showed that patients with intermediate disease durations had lower hazards than the shortest durations (0.5y to 13y compared to 14y to 22y, HR=.52, p=0.047; 0.5y to 13y compared to 23y to 32y, HR=0.60, p=0.094). The longest disease durations (32.85y to 51y) had hazards comparable to the shortest (HR=1.02, p=0.95). When restricted to MTS diagnosis, this relationship persisted (p=0.03). Our study suggests that children with MTS are less likely to become seizure free than young adults with the same diagnosis. We suspect that the relationship is not causative; rather, young children may have MTS on a different pathophysiological basis. In contrast, it is possible that patients with very long epilepsy duration may have worse outcomes due to the long-term effect of seizures. Along with prior studies of clinical and radiological findings and surgical outcome, this study should be taken into consideration in counseling patients on the likelihood of surgical success. (Supported by NS01692NIH/NINDS Neurological Sciences Academic Development Award (NSADA).)