Abstracts

Rationale: Epilepsy can be regarded as cured by surgery if the individual remains seizure-free having discontinued antiepileptic drugs (AEDs). We determined how common this optimal outcome is over long-term follow-up, and other patterns of outcome after epilepsy surgery. Methods: We obtained direct and complete annual follow-up data on 529 patients who had epilepsy surgery at the National Hospital for Neurology and Neurosurgery between 1990 and May 2006, with follow-up of 2-17 years. 459 were anterior temporal lobe resections. Seizure outcome was classified for every year of follow-up according to the 6-point ILAE Epilepsy Surgery Commission scale, and medication status noted. Results: At the latest follow-up 59% had been entirely seizure-free for the last year (Group 1), 37% continued to have seizures, including auras (groups 2-6), and 4% had died. 30% of seizure-free women and 27% of seizure-free men had discontinued AEDs. There were six principal patterns of outcome following surgery 1.Completely seizure-free from surgery: 38% 2.Seizures initially continuing, then terminal remission: both spontaneous & following a change in medication: 16% 3.Initial seizure freedom, then relapse: 8% 4.Seizure freedom, with transient relapse on stopping AEDs, then terminal remission after recommencing AEDs: 6% 5.Never seizure-free: 23% 6.Complex pattern of remissions and relapses: 4% 7.Epilepsy-related death: 2% 8.Unrelated death: 2% Conclusions: Surgical treatment brought complete and long-lasting seizure freedom to 38%, but 59% had terminal remissions of at least 1 year. The majority of seizure-free individuals elected to continue on AED. 23% of individuals did not have any seizure free years. 16% continued to have seizures after surgery, and subsequently remitted, often after introduction of a new AED, indicating that further medication changes are worthwhile.