Long-term seizure outcomes following epilepsy surgery: a systematic review and meta-analysis

• Published in: Brain (London, England : 1878) England : 1878), 2005-05, Vol.128 (5), p.1188-1198
• Main Authors: Téllez-Zenteno, José F., Dhar, Raj, Wiebe, Samuel
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; AED = anti-epileptic drug; Aged; Biological and medical sciences; Brain - surgery; Child; CI = confidence interval; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Epilepsy - surgery; Evidence-Based Medicine - methods; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; long-term outcome; Medical sciences; meta-analysis; MST = multiple subpial transection; Nervous system (semeiology, syndromes); Neurology; Neurosurgical Procedures - methods; Prognosis; seizure free; Systematic review; Temporal Lobe - surgery; Treatment Outcome
• ISSN: 0006-8950; 1460-2156
• DOI: 10.1093/brain/awh449

Assessment of long-term outcomes is essential in brain surgery for epilepsy, which is an irreversible intervention for a chronic condition. Excellent short-term results of resective epilepsy surgery have been established, but less is known about long-term outcomes. We performed a systematic review and meta-analysis of the evidence on this topic. To provide evidence-based estimates of long-term results of various types of epilepsy surgery and to identify sources of variation in results of published studies, we searched Medline, Index Medicus, the Cochrane database, bibliographies of reviews, original articles and book chapters to identify articles published since 1991 that contained ≥20 patients of any age, undergoing resective or non-resective epilepsy surgery, and followed for a mean/median of ≥5 years. Two reviewers independently assessed study eligibility and extracted data, resolving disagreements through discussion. Seventy-six articles fulfilled our eligibility criteria, of which 71 reported on resective surgery (93%) and five (7%) on non-resective surgery. There were no randomized trials and only six studies had a control group. Some articles contributed more than one study, yielding 83 studies of which 78 dealt with resective surgery and five with non-resective surgery. Forty studies (51%) of resective surgery referred to temporal lobe surgery, 25 (32%) to grouped temporal and extratemporal surgery, seven (9%) to frontal surgery, two (3%) to grouped extratemporal surgery, two (3%) to hemispherectomy, and one (1%) each to parietal and occipital surgery. In the non-resective category, three studies reported outcomes after callosotomy and two after multiple subpial transections. The median proportion of long-term seizure-free patients was 66% with temporal lobe resections, 46% with occipital and parietal resections, and 27% with frontal lobe resections. In the long term, only 35% of patients with callosotomy were free of most disabling seizures, and 16% with multiple subpial transections remained free of all seizures. The year of operation, duration of follow-up and outcome classification system were most strongly associated with outcomes. Almost all long-term outcome studies describe patient cohorts without controls. Although there is substantial variation in outcome definition and methodology among the studies, consistent patterns of results emerge for various surgical interventions after adjusting for sources of heterogeneity. The long-term (≥5 yea