Reducing VNS stimulation parameters: Is it safe?

Abstract

Introduction Vagal nerve stimulation (VNS) is an adjuvant therapy used in the treatment of patients with refractory epilepsy who are not candidates for resective surgery or who have limited results after surgical procedures. Currently, there is enough evidence to support its use in patients with various types of epilepsy. Therefore, the present study was conducted to explore the possibility of optimizing therapy by reducing the consumption of the system's battery.

Methods The prospective and double-blind analysis consisted in the evaluation of 6 patients submitted to VNS implantation for 3 months, followed by adjustment of the stimulation settings and continuity of follow-up for another month. The standard protocol was replaced by another with a frequency value of 20 Hz instead of 30 Hz to increase battery life. The safety of this procedure was evaluated through the assessment of two main variables: seizures and side effects.

Results The stimulation at 20 Hz showed 68% reduction in the incidence of seizures (p = 0.054) as well as low incidence of side effects.

Conclusion The present study suggests that the reduction of the stimulation frequency from 30 to 20 Hz is a safe procedure, and it does not compromise the effectiveness of therapy.

Resumo

Introdução A estimulação do nervo vagal (VNS, na sigla em inglês) é uma terapia adjuvante usada no tratamento de pacientes com epilepsia refratária que não são candidatos à cirurgia de ressecção ou que apresentam resultados limitados após procedimentos cirúrgicos. Atualmente, há evidências suficientes para apoiar seu uso em pacientes com vários tipos de epilepsia. Portanto, este estudo foi realizado para explorar a possibilidade de otimizar a terapia reduzindo o consumo da bateria do sistema.

Métodos A análise prospectiva e duplo-cega consistiu na avaliação de 6 pacientes submetidos ao implante de VNS por 3 meses, seguido de ajuste das configurações de estimulação e continuidade do seguimento por mais 1 mês. O protocolo padrão foi substituído por outro com um valor de frequência de 20 Hz em vez de 30 Hz para aumentar a vida útil da bateria. A segurança desse procedimento foi avaliada através da avaliação de duas variáveis principais: crises convulsivas e efeitos colaterais.

Resultados A estimulação em 20 Hz apresentou redução de 68% na incidência de convulsões (p = 0,054), bem como baixa incidência de efeitos colaterais.

Conclusão Este estudo sugere que a redução da frequência de estimulação de 30 para 20 Hz é um procedimento seguro e não compromete a eficácia da terapia.

Keywords

vagus nerve stimulation - vagal stimulation - VNS - refractory epilepsy

Palavras-chave

estimulação do nervo vago - estimulação elétrica - nervo vago - epilepsia resistente à medicamentos

Publikationsverlauf

Eingereicht: 04. Februar 2021

Angenommen: 06. September 2021

Artikel online veröffentlicht:
04. Januar 2022

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