Abstracts

RATIONALE: Detailed retrospective review of a large series of epilepsy surgical cases for medically refractory epilepsy by one surgeon at one center is reported. To the authors knowledge there is no large contemporary epilepsy surgery review from one modern epilepsy surgical team using uniform standards that can be used by another center as a guideline to compare their own outcome with. This report may serve as such a standard.
METHODS: This modern series spans 8 years beginning in 1994. Demographics, outcome, efficacy, complications, surgical indications, classification criteria, and surgical philosophy are discussed. Information presented covers 933 craniotomies, 88 bilateral invasive surveys, 69 single stage resections, 369 2-stage procedures, 42 3-stage procedures, 305 vagal nerve stimulator operations, and 38 stereotactic procedures. There are 682 unique patients, of which 480 underwent craniotomy. The average age for patients who had cranitotomy was 31 +/-12 years ranging from 0.3 to 75 years old. 47% were female.
RESULTS: Outcome is reported using a slightly modified Engle score. Single stage resections (primarily anterior medial temporal lobectomy with hippocampectomy) had 91/6/4/0% respectively for Engle 1/2/3/4 outcome with a 76% follow up. Two stage procedures involved a period of invasive monitoring prior to resection and yielded an outcome of 64/14/14/8% with a follow up of 81%. Three stage procedures yielded outcomes of 50/19/28/3% with 76% follow up. 1, 2, and 3 stage operations produced a decrease in 3 Engle grades from pre-op to post surgical state in 83%, 53%, and 41% of their associated patients respectively.
The majority of the presented efficacy data has over 2 years follow up. There was no mortality in this entire series and important morbidity or complications were infrequent. For all of the cranial procedures there were 15 infections and 9 hemorrhages representing a per craniotomy/per patient relative risk of 1%/1.8% for hemorrhage and 1.6%/3.1% risk for infection. Other noted morbidities are subdural hygromas, hydrocephalus, severe memory deficits and 3rd cranial nerve injury respectively in 0.4/0.8%, 0.1/0.2%, 0.5%/1.0% and [gt]0.1/[gt]0.1% risk. Bone resorption requiring cranioplasy occurred in 3 patients. No vascular injury, such as damage to the Anterior Choroidal Artery or Vein of Labbe, occurred.
CONCLUSIONS: Surgical philosophy was to tailor each case specifically to its unique circumstances, using in house surgical planning and navigation computer equipment, using custom designed electrodes to fit smaller cranial exposures, with liberal use of invasive monitoring for EEG characterization of the epileptogenic network and for extra operative functional mapping, and compulsive techniques to eliminate CSF leaking during invasive monitoring. More detailed and specific information of the demographics, surgical methods, and of the outcome data will be presented. Literature review reveals that our outcome is equal to or above all recently published reports.