Abstracts

Rationale: There is limited data about long-term outcomes of children with cortical dysplasia (CD) who have seizure recurrence after resective epilepsy surgery. We evaluated clinical determinants of terminal remission (TR; seizure free =12 mo at last follow-up) after epilepsy surgery in CD patients with postoperative seizure recurrence. Methods: We retrospectively reviewed CD patients who underwent resective epilepsy surgery at Cincinnati Children’s Hospital and had seizure recurrence during postoperative 1 month to 1 year. Patients with <2.5 years of post-surgical follow-up, genetic epilepsies (including tuberous sclerosis), previous epilepsy surgeries, palliative procedures, and multiple subpial transections without cortical excision were excluded. Seizure outcomes were ascertained longitudinally, and determinants of TR were explored using repeated-measures logistic regression. Results: Thirty-one patients (54% male) were included. After 5.52±2.06 years follow-up, 10 patients (32.2%) were seizure free at last follow up visit and 7 patients (22%) achieved TR. Even in patients with continued seizures at their last follow up visit, significant decrease in seizure frequency compared to pre-surgical baseline was noted (-53.1, 95% CI -95.6 to –10.4, p=0.016). Children with delayed occurrence of postoperative seizures (6.73± 5.33 months) were more likely to achieve TR compared to those with earlier recurrence (1.93 ± 2.87 months). Odds of achieving TR increased by 1% every post-operative day without seizure recurrence (p=0.017). Other presurgical variables including age of seizure onset, seizure frequency, age at the surgery, interval between seizure onset and surgery, having multiple seizure semiologies, number of failed anti-seizure drugs, history of status epilepticus, febrile seizures, and developmental delay showed no significant association with TR. Potentially epileptogenic MRI lesion(s) were seen in 16 (51.6%) patients, with concordance of MEG (75%), SPECT (87%), and PET (87%). MRI lesion and concordance of functional studies did not correlate with TR. Twenty six patients were evaluated with subdural grids, 12 (38.7%) underwent temporal lobe surgery, and 21 (67%) had left hemispheric surgeries. On neuropathology, CD types 1-3 were seen respectively in 16 (51.6%), 8 (25.8%), and 2 (6.5%) patients, with a mixed pattern in 5 (16.1%) patients. These surgical variables were not associated with TR. Four of 6 patients who underwent repeat surgery were seizure free at their last follow-up. Conclusions: Among CD patients with seizure recurrence after epilepsy surgery, 32.2% were seizure free after 5.5 years of follow up, and 22% achieved TR. Delayed occurrence of postoperative seizures was associated with a higher likelihood of achieving eventual TR. Funding: None