Long-term outcome after temporal lobe epilepsy surgery in 434 consecutive adult patients

Clinical article

Alaa Eldin Elsharkawy M.Sc., M.D.2,3, Abdel Hamid Alabbasi Ph.D.4, Heinz Pannek M.D.2, Falk Oppel M.D., Ph.D.2, Reinhard Schulz M.D.1, Mathias Hoppe M.D.1, Ana Paula Hamad M.D.1,5, Mohamed Nayel M.D., Ph.D.3, Ahmed Issa M.D., Ph.D.3, and Alois Ebner M.D.1
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  • 1 Department of Presurgical Evaluation; and
  • | 2 Neurosurgical Department, Bethel Epilepsy Centre, Bielefeld, Germany;
  • | 3 Neurosurgical Department; and
  • | 4 Department of Biostatistics and Demography, Institute of Statistical Studies and Research, Cairo University, Cairo, Egypt; and
  • | 5 Federal University of São Paulo, Brazil
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Object

The aim of this study was to evaluate the long-term efficacy of temporal lobe epilepsy (TLE) surgery and potential risk factors for seizure recurrence after surgery.

Methods

This retrospective study included 434 consecutive adult patients who underwent TLE surgery at Bethel Epilepsy Centre between 1991 and 2002.

Results

Hippocampal sclerosis was found in 62% of patients, gliosis in 17.3%, tumors in 20%, and focal cortical dysplasia (FCD) in 6.9%. Based on a Kaplan-Meier analysis, the probability of Engel Class I outcome for the patients overall was 76.2% (95% CI 71–81%) at 6 months, 72.3% (95% CI 68–76%) at 2 years, 71.1% (95% CI 67–75%) at 5 years, 70.8% (95% CI 65–75%) at 10 years, and 69.4% (95% CI 64–74%) at 16 years postoperatively. The likelihood of remaining seizure free after 2 years of freedom from seizures was 90% (95% CI 82–98%) for 16 years. Seizure relapse occurred in all subgroups. Patients with FCD had the highest risk of recurrence (hazard ratio 2.15, 95% CI 0.849–5.545). Predictors of remission were the presence of hippocampal atrophy on preoperative MR imaging and a family history of epilepsy. Predictors of relapse were the presence of bilateral interictal sharp waves and versive seizures. Six-month follow-up electroencephalography predicted relapse in patients with FCD. Short epilepsy duration was predictive of seizure remission in patients with tumors and gliosis; 28.1% of patients were able to discontinue antiepileptic medications without an increased risk of seizure recurrence (hazard ratio 1.05, 95% CI 0.933–1.20).

Conclusions

These findings highlight the role of etiology in prediction of long-term outcome after TLE surgery.

Abbreviations used in this paper:

AED = antiepileptic drug; ECoG = electrocorticography; EEG = electroencephalography; FCD = focal cortical dysplasia; HR = hazard ratio; HS = hippocampal sclerosis; IED = interictal epileptiform discharge; MTS = mesial temporal sclerosis; TLE = temporal lobe epilepsy.

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