PREDICTORS OF OUTCOME OF ANTERIOR TEMPORAL LOBECTOMY FOR INTRACTABLE EPILEPSY - A MULTIVARIATE STUDY

Objective: To identify presurgical and postsurgical factors that are i ndependently predictive of the outcome of anterior temporal lobectomy (ATL) for intractable epilepsy. Background: There have been reports of prognostic factors in epilepsy surgery, but little is known about fac tors that independently predict outcome of ATL. Methods: We studied 17 5 consecutive ATL patients who had at least 2 years of postsurgical fo llow-up. Significant factors on univariate analyses were subjected to stepwise logistic regression analysis. Results: On univariate analyses , two presurgical conditions were significantly associated with excell ent seizure control at last follow-up: (1) unilateral hippocampal form ation atrophy as detected on MRI and (2) all scalp interictal epilepti form discharges concordant with the location of ictal onset (p < 0.05) . Three postsurgical factors that occurred during the first year were associated with excellent seizure outcome: the absence of interictal e pileptiform discharges at 3 months, complete seizure control, and havi ng only nondisabling seizures for those who did not become seizure fre e. Logistic regression analysis revealed the following to be independe ntly predictive of excellent seizure control: MRI-detected unilateral hippocampal formation atrophy, concordant interictal epileptiform disc harges, complete seizure control during the first postsurgical year, a nd having only nondisabling seizures during the first postsurgical yea r for those who did not become seizure free. Conclusions: Presurgical identification of unilateral hippocampal formation atrophy, or of inte rictal epileptiform discharges that are all concordant with the locati on of ictal onset, predict excellent outcome of ATL. However, the prob ability of excellent outcome is highest (94%) when both factors are pr esent.