Abstracts

Rationale: Rarely, patients undergo reoperation following a failed initial surgical procedure for the treatment of refractory epilepsy. We sought to determine indicators of favorable outcome following reoperation in a pediatric cohort. Methods: Patients were identified from an epilepsy surgical database at the Miami Children’s Hospital Brain Institute. We included all patients younger than 18 years of age at the time of their first surgery who required reoperation at Miami Children’s Hospital for the treatment of refractory epilepsy and had at least 1 year of follow-up after each subsequent surgery. Patients who underwent corpus callosotomy, placement of a vagal nerve stimulator, or multiple subpial transections as their initial procedure were excluded. We also excluded patients undergoing surgery at another institution. Patients were dichotomized into those that improved after reoperation, characterized as at least one grade improvement by Engel’s classification, and those that did not. Twenty-five pre- and perioperative variables were compared amongst the two groups to determine predictors of favorable outcome. Results: Twenty-four patients met inclusion criteria (mean age 2.1y, range 0-10y). Nineteen (79%) had a MRI-evident lesion prior to their first surgery. The reason for initial surgical failure was incomplete resection not limited by eloquent cortex (11, 46%), incomplete resection as a result of eloquent cortex (9, 37%), or multifocal areas of epileptogenesis (4, 17%). Eighteen (75%) patients underwent extension of the prior resection, while 6 (25%) required resection of a new independent focus. Thirteen (54%) patients were improved after a second procedure, of which 10 (42%) were seizure-free at 2 years follow-up. Those patients that demonstrated improvement were more likely to have had complete resection of the epileptogenic zone (p=0.04). Amongst patients that improved post-op, 8 (62%) underwent hemispherectomy and 5 (38%) had focal lobar resections. Within the group without improvement, only 1 (9%) underwent hemispherectomy and 10 (91%) had lobar resections (p=0.03). Conclusions: Children that fail an initial surgical procedure for intractable epilepsy should be evaluated for reoperation. The most common reason for initial surgical failure was incompleteness of resection, and those with complete resection of the epileptogenic zone after the second procedure were more likely to benefit from reoperation. While hemispherectomy resulted in seizure freedom in a high proportion of patients, focal resections were beneficial in one-third of our cases.