Ten years’ experience with vagus nerve stimulation in a paediatric population
Introduction. Fifty million people are affected by epilepsy. Up to 30% are not controlled with the aid of antiepileptic drugs. The vagus nerve stimulator (VNS) is a therapeutic alternative that must be taken into account.
Aim. To determine the effect of the VNS in a cohort of paediatric patients with refractory epilepsy.
Patients and methods. A retrospective study of children with a VNS implanted between 2008 and 2017 in a tertiary hospital. Epidemiological, aetiological, clinical and electrophysiological data, along with VNS parameters were analysed.
Results. The study included 35 patients, with a mean age when the VNS was implanted of 12.84 years (range: 3.1-18.7 years) and a mean time between onset of epilepsy and implantation of 7.2 years (range: 1.3-17.7 years). The causation was structural in 62.9% of cases. The most frequent epileptic conditions were: Lennox-Gastaut syndrome and focal epilepsy, with a predominance of tonic seizures (57.1%). The video electroencephalogram showed multifocal anomalies (54%) and a pattern of epileptic encephalopathies (34.3%). Intellectual disability was associated in 94% of the cases. The mean of previous antiepileptic drugs was 9.6 ± 3 (range: 4-16). 43% responded to treatment (≥ 50% reduction in number of seizures), with a mean reduction of 67.3%, which improved with higher ages of onset of epilepsy. Three patients were seizure-free (8.5%). The number of seizures decreased by 33% at six months and by 47.4% at 24 months. There was also a notable degree of cognitive (57%) and behavioural improvement (53%). In 28% of cases there were some side effects, but in general they were mild.
Conclusions. The VNS is a valid option in refractory epilepsy, with improvements not only in terms of seizures but also regarding cognitive-behavioural aspects, this being very important for the paediatric population.
Key words. Efficacy. Paediatrics. Refractory epilepsy. Safety. Treatment. Vagus nerve stimulator.