Patients who undergo vagal nerve stimulation to treat drug-resistant epilepsy may experience certain complications and repeat surgeries should be avoided wherever possible, scientists have claimed.
Researchers at Umea University Hospital in Sweden conducted a study to assess the complications that may occur following this treatment, in which a stimulator device is implanted – usually into the chest – and delivers electrical impulses to the vagus nerve in the neck via electrodes.
The nerve affects areas of the brain involved in the onset of seizures, so vagal nerve stimulation aims to interrupt or prevent the development of seizures.
However, relatively little is known about the rates of surgical and hardware complications that occur in patients who undergo this relatively new form of treatment.
The Swedish research team analysed outcomes for 143 patients, including 81 men and 62 women, who had a vagal nerve stimulation device implanted between 1994 and 2010 to treat drug-resistant epilepsy.
Participants were followed up for an average of 62 months to see whether they developed any complications.
Analysis revealed that 16.8 per cent of the patients were affected by complications related to the surgery itself, while a similar proportion experienced hardware malfunctions.
The most common surgical complications were superficial infections (3.5 per cent of patients), deep infection requiring the removal of the implant (3.5 per cent) and vocal cord palsy (5.6 per cent).
Hardware-related complications included lead fracture (11.9 per cent), disconnection (2.8 per cent), spontaneous turn-off (1.4 per cent) and stimulator malfunction (1.4 per cent).
The researchers found some evidence that of the two most commonly used lead models, one may have a tendency to last longer than the other.
Their findings also suggest that the more stimulator replacements patients underwent, the greater their risk of infection.
Publishing their findings in the journal Seizure, the study authors observed: “Infection following insertion of the vagal nerve stimulation device and vocal cord palsy due to damage to the vagus nerve are the most serious complications related to the surgery.
“Avoiding unnecessary reoperations in order to reduce the appearances of these complications are of great importance.”
Posted by Steve Long, Epilepsy Research UK