Abstracts

Rationale: Corpus callosotomy is a disconnective surgical treatment for patients with refractory epilepsy, typically characterised by injurious drop attacks. The literature supports the use of corpus callosotomy as an effective palliative treatment for drop attacks and suggests that younger patients tend to have a better prognosis than older patients (Asadi-Pooya et al. Epilepsy Behav 2008;13(2):271-8). This paper describes a decade of experience with corpus callosotomy at Great Ormond Street Hospital for Children (GOSH) in London and the Children’s Hospital at Westmead (CHW) in Sydney.Methods: An intention to treat analysis was performed on the patient records during the period January 2003 – December 2013. Engel Class I or II for drop attacks defined a satisfactory outcome and was used for the primary outcome measure. The number of patients who developed surgical complications or postoperative morbidity were used as secondary outcome measures. Chi-square and Mann-Whitney U tests were used to analyse descriptive statistics. Multivariate regression analysis was conducted in order to control for age at surgery, developmental delay and extent of callosotomy.Results: 40 patients met inclusion criteria, 27 from GOSH and 13 from CHW, with a median follow up of 1.54 years (interquartile range (IQR) 2.04 years). There were no significant differences in patient demographics or outcomes between the two centres, despite CHW restricting surgery to total corpus callosotomy. 73.2% of patients had Engel Class I-II for drop attacks, with no significant difference between effectiveness of total corpus callosotomy and partial corpus callosotomy (p=0.20, χ2=1.67). All complications following surgery resolved within 6 weeks of surgery. No patients who underwent total corpus callosotomy developed disconnection syndrome, whereas 11% of patients developed disconnection syndrome following anterior 2/3 corpus callosotomy; this difference was not significant (p=0.06, χ2=3.53). Other neurological complications included left-sided weakness/hemiparesis, aphasia/decreased speech and increased seizures. These occurred following 22.5% of total corpus callosotomy and 0% of partial corpus callosotomy, but there was no significant difference (p=0.12, χ2=2.47). Regression analysis showed that extent of the callosotomy (adjusted odds ratio (AOR)=1.30; 95% confidence interval (CI)=1.26-1.34), patients with intelligence quotient (IQ) <50 (AOR=1.26; 95% CI=1.22-1.30), and age below the median age of the cohort (AOR=1.13; 95% CI=1.10-1.17) were prognostic of good outcome, however these factors only accounted for 36% of the variance (R2=0.36).Conclusions: Corpus callosotomy is an effective palliative treatment for patients with refractory epilepsy, especially in younger patients. Total corpus callosotomy should be considered over partial corpus callosotomy in patients with significant developmental delay or intellectual disability.