Morbidity and infection in combined subdural grid and strip electrode investigation for intractable epilepsy

The coverage of large surface areas of the brain for electrographic monitor ing purposes necessitates a craniotomy to achieve comprehensive sampling. W e undertook a review and prospective analysis over 3 years of 38 patients u ndergoing craniotomy for electrode implantation. The indication for invasiv e monitoring was to determine candidacy for resective surgery in patients w hose seizure focus was not well localized by scalp electroencephalography a nd other noninvasive testing. Prophylactic cultures from the epidural space were obtained at electrode removal. There were five positive epidural cult ures. All five patients went on to seizure-free status. Two positive cultur es occurred in patients without obvious infection and who were not treated with antibiotics. Other complications included individual cases of atrial f ibrillation, pulmonary edema, postoperative fever, and epidural hematoma. T here was no mortality or permanent neurologic morbidity related to cranioto my for electrode placement. There was a 7.9% rate of clinical infection per patient and a 5.7% rate per craniotomy side. This study has identified sev eral factors that significantly correlate with positive epidural culture re sults: > 100 electrodes, more than ten cables, more than 14 days of implant ation, and more than one cable exit site. (C) 1999 Elsevier Science B.V. Al l rights reserved.