Abstracts

Rationale: Epilepsy surgery procedures started in Argentina more than 50 years ago. This is the first comprehensive and systematic survey of epilepsy surgery long-term outcome from our country. Eighty percent of patients suffering from epilepsy worldwide live in developing countries. Epilepsy surgery now affords an excellent opportunity to suppress seizure activity, improving quality of life and outweighing risks inherent to the procedure itself. Methods: A descriptive retrospective cohort study using information from epilepsy surgery databases was conducted. All patients operated between 1998 and 2008 for drug-resistant epilepsy was analyzed. One hundred and fifty cases were operated on, only cases with a minimum of 12 months follow-up were included (N=110). In 88 cases (80%) resective surgery was performed, and outcome periodically assessed using the Engel score. Engel s score was systematically assessed by epileptologists or neurosurgeons in follow up visits. When patients were not available for personal interview, Engel scores were obtained via telephone interview. Patients were stratified into groups according to follow-up duration as follows: 12 months, 13-36 months, 37-60 months and over than 60 months and were grouped according procedure. Standard epilepsy MRI protocol was used to study all patients. Use of Video-EEG (VEEG) monitoring prior to surgery, intracranial electrode implants, intraoperative electrocorticograms (ECoG) and Wada tests was also evaluated. Pathology reports, use of antiepileptic drugs (AEDs) before and after surgery, immediate and long-term mortality and surgical complication rates were also analyzed. Results: Surgical techniques included: 69 lobectomies (62.7%), 15 lesionectomies (13.6%), 6 callosotomies (5.4%), 6 multiple subpial transection (5.4%), 11 vagus nerve stimulations (10%), 3 hemispherectomies (2.7%). AEDs were discontinued in 19 patients (17.3%). Mean follow-up: 46 months. Male: female ratio: 1/1.44. Mean age at time of surgery: 26.2 years. Mean duration of epilepsy: 14 years. Age at seizure onset: 11.5 years. Pathology findings: mesial temporal sclerosis 32 (36.4%); dual pathology 17 (19.3%); cortical dysplasia 15 (17%); non-specific inflammatory changes 11 (12.5%); tumours 7 (8%); other 6 (6.8%). All patients were evaluated by VEEG monitoring. Intracranial electrodes: 32 patients (29.1%), intraoperative ECoG: 34 patients (30.9%) and Wada test: 42 (38.2%). Engel scores at 12 months follow-up: 69.3% (61) class I, 15.9% (14) class II and 14.7% (13) class III-IV; 13-36 months after surgery: 68.1% of cases were class I, 15.9% class II and 15.5% class III-IV. After 37-60 months follow-up, 70.6% class I, 15.7% class II, 13.7% class III-IV. Over 60 months (n = 45) 76.3% class I, 15.8% class II and 7.9% class III-IV. No complications were observed in 97 cases (88%). Conclusions: Conducting a successful epilepsy surgery program in a developing country is challenging. These results should encourage specialists in these countries to study this population, train specialized staff and acquire appropriate technology. Long-term outcome results comparable to centres in developed countries can be achieved.