Abstracts

Rationale: Children and young people with refractory seizures have a significant morbidity and disability. Corpus callosotomy and vagus nerve stimulation (VNS) therapy are two commonly used palliative epilepsy surgeries for children with medical resistant epilepsy not amenable to curative resective surgical procedures. The aim of this study was to compare the efficacy of corpus callosotomy and vagus nerve stimulation (VNS) for the treatment of drop attacks. Methods: Retrospective case notes review of children and young people with drop attacks as mainly and more disabling type of seizures underwent corpus callosotomy or vagus nerve stimulation (VNS) at Great Ormond Street Hospital between 1993 and 2009. Our Service has been implanting VNS since 2005. Results: Corpus callosotomy: from 1993 to 2004, six patients (83% male), with a mean age seizure onset 3.6 3.3 years and surgery 12 5 years. 2/ 6 had a normal brain MRI. At the last follow up, only one patient was drop attack free but was not seizure free. Following surgery, one child developed a mild monoparesis which rapidly improved. One child underwent completion of callosotomy, and two have been offered VNS implantation. Since 2005, twelve patients (75% male), with a mean age at seizure onset of 1.6 2 years and at surgery of 11 5 years, have been identified. 7/ 12 had a normal MRI. One of them had a previous right temporal lobectomy and two had previous VNS implant. At the last follow up, one patient was drop attack free but was not seizure free. Following surgery, one child showed some degree of in-coordination, another child had left-sided weakness; both improved over time. One had difficulty in initiating speech. Two children underwent completion of callosotomy and further 4 have been evaluated for VNS implantation. VNS: seven patients (29% male), with mean age seizure onset 3.6 3.4 years and surgery 10 5.1 years. 4/ 7 had a normal brain MRI. No child was drop attack and seizure free at last follow up. In one child the device was switched off for inefficacy and two children have been evaluated for callosotomy. Conclusions: This preliminary study both corpus callosotomy and VNS reduce seizure frequency in children with intractable epilepsy not candidates for curative resective surgical procedures, but have an equal chance of effect on drop attacks. They were both safe with a low incidence of complications after surgery.