Abstracts

RATIONALE:evaluation of complication rate of invasive recording with subdural grids and depth electrodes in epilepsy surgery in children METHODS:From 1992 to 1999 invasive recording was performed in 83 children, aged 4 mths to 17 years (m=7,5y) using both subdural grids and depth electrodes. The number of electrodes was 64 to 104 (m=80), the length of recording was 4 to 9 days (m=6). Site was frontal(26), temporal(22),central(15),parietal(6),occipital(1), bilobar(10), trilobar(3).Cortical mapping (motor or speech) was done in 38 cases. 6 children had no surgery after recording, 77 underwent excisionnal surgery with or without subpial tansection. Etiology was dysplasia(40), tumors(19), other(12),6 were cryptogenic. According to engel classification, results in 73 children with more than 6 months of follow up(6mths-7y, m=2,7y),are 43 class I(60%), 5 class II(7%), 16 classIII(22%), 9 class IV(11%).Technique was modified in the end of 97,instead of using one single separate skin incision for all the wires, each wire is issued percutaneously using a Tuohy needle.that avoid any csf leakage during the recording time. RESULTS:From 92 to 97 (45 case), complication were: 2subdural hematomas, 2 meningitis, 2 wound infections. since 98 (38 cases) 1 subdural hematoma, no other complication. 2 of the 3 cases of hematoma had a prior surgery for a tumor resection. in the 3 cases,clinical symptoms were headache, it was possible to remove the hematoma without interruption of the recording. there were no mortality, no deficit due to invasive recording, and since the technical modification, the infection rate which was 9% before 97 is now 0%. CONCLUSIONS:in all the cases in which an invasive recording is necessary to perform epilepsy surgery in children, when a stereoeeg is not feasible considering the age of the child or the need for a cortical mapping, the assocation of subdural grids and depth electrodes is a safe method with a very low rate of complication and which brings precise data to achieve an accurate surgery. the main contraindication is a prior surgery in the same area.surgical technique must avoid any risk of csf leakage during the recording period.