Pediatric Vagus Nerve Stimulation: Case Series Outcomes and Future Directions

Abstract

BACKGROUND:Vagus nerve stimulation (VNS) is a neuromodulatory procedure most extensively studied as an adjunct to medically refractory epilepsy. Despite widespread adoption and decades of clinical experience, clinical predictors of response to VNS remain unclear.OBJECTIVE:To evaluate a retrospective cohort of pediatric patients undergoing VNS at our institution to better understand who may benefit from VNS and identify factors which may predict response to VNS.METHODS:We conducted a retrospective cohort study examining pediatric patients undergoing VNS over nearly a 20-year span at a single institution. Presurgical evaluation, including demographics, clinical history, and diagnostic electroencephalogram, and imaging findings were examined. Primary outcomes included VNS response.RESULTS:Two hundred ninety-seven subjects were studied. The mean age at surgery was 10.1 (SD = 4.9, range = 0.8-25.3) years; length of follow-up was a mean of 4.6 years (SD = 3.5, median = 3.9 years, range 1 day-16.1 years). There was no association between demographic factors, epilepsy etiology, or genetic basis and VNS outcomes. There was an association between reduction in main seizure type with positive MRI finding. Of all MRI findings analyzed, brain atrophy was significantly associated with worse VNS outcomes, whereas dysplastic hippocampus and chronic periventricular leukomalacia findings were found to be associated with improved outcomes. Increased seizure semiology variability and seizure type were also associated with improved seizure outcomes.CONCLUSION:Predicting response to VNS remains difficult, leading to incompletely realized benefits and suboptimal resource utilization. Specific MRI findings and increased seizure semiology variability and type can help guide clinical decision making and patient counseling.

Analysis of factors influencing the efficacy of vagus nerve stimulation for the treatment of drug-resistant epilepsy in children and prediction model for efficacy evaluation

“…This study did not find a clear correlation between the duration of epilepsy and the efficacy of VNS ( P = 0.917). LoPresti et al found that brain atrophy was associated with worse VNS outcomes, while dysplastic hippocampus and chronic periventricular leukomalacia findings were found to be associated with better VNS outcomes ( 18 ). It has also been shown that patients with low seizure frequency (< 20 seizures/month) have a better prognosis ( 49 ).…”

“…However, VNS is still a treatment that relies on the clinician's experience, and the clinical outcome of patients cannot be predicted preoperatively. Although many studies have explored the predictive factors of VNS efficacy in recent years, the results are not entirely consistent (18,19,28). Currently, there is still a lack of preoperative predictive indexes for the efficacy of VNS in the clinic.…”

“…Prognostic factors were selected based on evidence provided in literatures (6,(17)(18)(19). They were believed to be potentially clinical indicators of patient's response to VNS treatment for DRE, including: sex, seizure frequency, age at seizure onset, age at implantation, duration of epilepsy, epileptic syndromes, major type of seizures, cranial MRI changes, duration of seizure, history of hypoxic-ischemic encephalopathy, history of encephalitis, intellectual disability, history of status epilepticus, duration of VNS stimulation, types of ASMs ever used, and types of ASMs before VNS.…”