Importance Surgical treatment can bring seizure remission in people with focal epilepsy but requires careful selection of candidates.
Objectives To determine which preoperative factors are associated with postoperative seizure outcome.
Design We audited seizure outcome of 693 adults who had resective epilepsy surgery between 1990 and 2010 and used survival analysis to detect preoperatively identifiable risk factors of poor seizure outcome.
Results Seven factors were significantly associated with increased probability of recurrence of seizures with impaired awareness postsurgery: MRI findings (eg, HR adjusted for other variables in the model 2.5; 95% CI 1.6 to 3.8 for normal MRI compared with hippocampal sclerosis), a history of secondarily generalised convulsive seizures (2.3; 95% CI 1.7 to 3.0 for these seizures in the previous year vs never), psychiatric history (1.3; 95% CI 1.1 to 1.7), learning disability (1.8; 95% CI 1.2 to 2.6) and extratemporal (vs temporal) surgery (1.4; 95% CI 1.02, 2.04). People with an older onset of epilepsy had a higher probability of seizure recurrence (1.01; 95% CI 1.00, 1.02) as did those who had used more antiepileptic drugs (1.05; 95% CI 1.01 to 1.09). Combinations of variables associated with seizure recurrence gave overall low probabilities of 5-year seizure freedom (eg, a normal MRI and convulsive seizures in the previous year has a probability of seizure freedom at 5 years of approximately 0.19).
Conclusions and relevance Readily identified clinical features and investigations are associated with reduced probability of good outcome and need consideration when planning presurgical evaluation.
- epilepsy surgery
- mesial temporal epilepsy
- extratemporal epilepsy
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Contributors JSD conceived this evaluation. JdT collected the data. JCG-F designed and maintained the database. GSB did data analysis and drafted the report. JLP provided statistical support and data interpretation. BD, JWS and JSD selected people for the surgical procedures. AWM and WFJH did the surgical procedures; JF and RAP obtained psychiatric data. BD, JWS and JSD did data interpretation and editing. All approved the final version.
Funding This work was undertaken at UCLH/UCL, which receives a proportion of funding from the UK Department of Health’s National Institute for Health Research (NIHR) Biomedical Research Centres funding scheme, Epilepsy Society, and from Marvin Weil Epilepsy Research Fund.
Competing interests GSB and her husband have shares in GlaxoSmithKline. JdT, JLP, JF and RAP report no disclosures. AWM has received lecture fees and travel bursaries from Baxter, Eisai, UCB, Forth Medical, Fannin and Cyberonics. He has had departmental and research support from Cyberonics and Medtronic. WFJH has been consulted by and received research grants and fees for lectures from Forth Medical. JWS has been consulted by and received fees for lectures from Eisai, GlaxoSmithKline, Teva, Lundbeck and UCB. He has had departmental and research support from Eisai, UCB, NL Epilepsy Funds and the Dr Marvin Weil Epilepsy Research Fund. JSD has been consulted by and received research grants and fees for lectures from Eisai, GE Healthcare; he has had departmental and grant support from Medtronic, Cyberonics, NIHR, MRC and Wellcome Trust. BD has grant support from Epilepsy Research UK and the National Institute for Neurological Disorders and Stroke (NINDS). JLP is supported by NIHR Biomedical Research Centre at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London, UK, and is NIHR senior investigator.
Ethics approval Research Ethics Committee, NHNN.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement We will share anonymised clinical data with other investigators on request and within the requirements of UCLH information governance.
Correction notice This article has been corrected since it was pulbished Online First. Table 1, row F, Verbal IQ now reads Verbal IQ >70. Similarly, Performance IQ now reads Performance IQ >70. Table 3, Performance IQ now reads Performance IQ (vs >70). And the following text has been updated to read: ’with more of those with IQ >70 being seizure free'.