Vagus nerve stimulation for drug-resistant epilepsy in children indications

Vagus nerve stimulation for drug-resistant epilepsy was approved for pediatric epilepsy and adults in Europe in 1994. ¹⁾.

In 1997, the US Food and Drug Administration (FDA) approved Vagus nerve stimulation for drug-resistant epilepsy in children aged ≥ 12 years, who were poor candidates or had failed to gain curative effects by various therapeutic approaches such as ketogenic diet, resection surgery, and palliative surgery ^{2) 3) 4) 5)}.

The commonly used VNS system (Cyberonics, Inc., Houston, TX, USA) was approved by the FDA (2017) for use in patients over 4  years of age who exhibit partial-onset seizures, who are refractory to antiepileptic drugs based on retrospective analysis ⁶⁾. Indeed, many clinical studies suggest that Vagus nerve stimulation is as effective in children as it is in adult patients ^{7) 8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19)}.

A retrospective study using a large sample size in children (N = 347) has shown that VNS reduces the frequency of seizures and is well tolerated for over 2-years’ follow-up ²⁰⁾

More specifically, 40–50% of pediatric patients had reached > 50% reduction compared to baseline seizure frequency of the predominant seizure type. Several studies have found similar levels of efficacy for VNS treatment in pediatric patients with refractory epilepsy during 1–10 years of treatment ^{21) 22) 23) 24) 25) 26) 27) 28) 29) 30) 31) 32) 33)}.

Interestingly, age may be an important factor affecting the efficacy of VNS in children, as previous data have shown that younger participants demonstrate greater improvements following VNS intervention ^{34) 35)}.

Most studies have observed stable cognitive function during VNS treatment, with some studies reporting mild positive effects on verbal performance, memory and/or mental state in children independent of seizure control ^{36) 37) 38) 39) 40)}.

Reliable identification of VNS responders is critical to mitigating surgical risks for children who may not benefit and to ensure cost-effective allocation of health care resources ⁴¹⁾.

Nine economic evaluations involving children with drug-resistant epilepsy were identified. All studies involved pharmacologic treatments compared with other pharmacologic treatments or non-pharmacologic treatments (i.e., ketogenic diet, epilepsy surgery, vagus nerve stimulation). Few studies have assessed the cost-effectiveness of pharmacologic treatments in specific drug-resistant epilepsy syndromes, including Dravet and Lennox-Gastaut syndromes. Five included studies involved the use of Markov models with a similar structure (i.e., health states based on seizure frequency relative to baseline). There was a wide range of methodological quality, and few studies fully addressed context-specific issues such as weight gain and treatment switching ⁴²⁾.

In focal epilepsy in children caused by GATOR1 complex gene variation, 2 of them failed with vagus nerve stimulation and ketogenic dietary therapy as well ⁴³⁾.