Case Control Study of Mortality after Epilepsy Surgery.
Abstract number :
G.07
Submission category :
Year :
2001
Submission ID :
212
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
M.R. Sperling, MD, Neurology, Thomas Jefferson University, Philadelphia, PA; A.D. Harris, BA, Neurology, Thomas Jefferson University, Philadelphia, PA; M. Nei, MD, Neurology, Thomas Jefferson University, Philadelphia, PA; J.D. Liporace, MD, Neurology, Tho
RATIONALE: People with refractory epilepsy have high mortality rates. We previously found a strong association between seizure control and survival after epilepsy surgery. In this analysis, we assessed other variables to see which were related to mortality after controlling for seizure recurrence.
METHODS: All data was drawn from a prospectively maintained surgical database. A case-control analysis was performed. All patients who died after epilepsy surgery were included as case subjects. 3 controls were selected for each case, chosing surviving patients with recurrent seizures who had the next 3 operations after each case[ssquote]s operation. Controls were required to have postoperative seizures to control for seizure recurrence. Cases and controls were compared with univariate analyses using Mann-Whitney, Chi square, and t-tests where appropriate.
RESULTS: Of 656 patients who had surgery, 21 later died and were included as patient subjects. Twenty of the 21 patients who died had postoperative seizures. 14 had temporal lobectomy, 1 had a parietal resection, and 6 had callosotomies. 63 control subjects were used. The first analyses were done in the 11 patients who died of SUDEP. Postoperative seizure frequency was the only variable that differed between SUDEP patients and controls. SUDEP patients had more seizures in the year preceding death than control subjects (Mann-Whitney, p=.01). There was a weak trend for greater prevalence of postoperative tonic-clonic seizures among patients who died than in controls (p = .14). Presence of a risk factor for epilepsy, pathology, type of operation (resection vs callosotomy), IQ, and number of antiepileptic medications were not risk factors for SUDEP. For the entire patient sample (n = 21), none of the above variables were associated with increased risk of death.
CONCLUSIONS: While the presence of seizures after surgery is the major risk factor for postoperative SUDEP, seizure frequency appears to be an independent risk factor as well. This suggests that ictal rather than interictal mechansims have a major role in SUDEP in patients with refractory epilepsy.