Mortality after temporal lobe epilepsy surgery

Abstract

Purpose: To report mortality, after a longer interval, in a cohort of patients with drug-resistant epilepsy treated by temporal lobe surgery between 1975 and 1995. A previous audit of these patients ending December 1, 1997 observed a standardized mortality ratio (SMR) of 4.5.

Methods: We analyzed mortality in a cohort of 306 patients with temporal lobe epilepsy (TLE) who underwent temporal lobe resections between December 1, 1975 and December 1, 1995. Deaths occurring after December 1,1997 and until December 1, 2009 were evaluated. Medical records, death certificates, postmortem examination reports, coroner officer's reports, and coroner's inquest reports were sought, and causes of death were ascertained. Sudden unexpected death in epilepsy (SUDEP) cases were identified.

Key findings: In 3,569 person-years of follow-up 19 deaths occurred, [SMR 2.00, 95% confidence interval (CI) 1.27-3.13], 14 men (SMR 2.01, 95% CI 1.19-3.39) and 5 women (SMR 1.68, 95% CI 0.70-4.03). On analysis of subgroups, SMRs were significantly elevated in patients with mesial temporal sclerosis (MTS) (SMR 2.50, 95% CI 1.38-4.51), men with MTS (SMR 3.12, 95% CI 1.56-6.25), men with nonspecific lesions (SMR 2.68, 95% CI 1.00-7.09), and right-sided resections in MTS (SMR 3.33, 95% CI 1.39-8.00). During follow-up, six SUDEP cases were observed with a rate of 1/595 person-years.

Significance: In this cohort, the risk for premature death in patients undergoing TLE surgery decreased over time but remained above the standard population. Men had a slightly higher risk than women, as did right-sided resections in MTS, confirming this observation in the original cohort. Although lower, the risk of SUDEP remained. Without up-to-date information on seizure outcome, we were unable to directly relate this to mortality.