Vagus Nerve Stimulation Surgery Generally Safe for Drug-Resistant Epilepsy

Among patients with drug-resistant epilepsy, surgical procedures that target vagus nerve stimulation (VNS) are relatively safe and have a low incidence and rate of complications, according to the findings of a retrospective cohort study published in the journal Brain and Spine.

VNS surgery has been widely adopted as a therapy for drug-resistant epilepsy. In addition to implantation of the VNS system, other surgeries are typically required to replace generators or leads, or to partially or fully remove an ineffective implant on patient request. Complication rates may differ for each type of surgery, but researchers typically do not compare these complication rates within a single study. It is also unclear how various risk factors are related to each surgery type.

For this study, a team of researchers reviewed records from the Maastricht University Medical Center in the Netherlands for all types of VNS surgeries performed there between January, 2008 and October, 2022. This review comprised 606 surgical procedures, in 437 patients with drug-resistant epilepsy. For each type of surgery (implantation, generator replacement, revision surgery, or removal), the team examined risk factors including duration of surgery, duration of pre-incision antibiotic administration, body mass index (BMI), diabetes, and smoking.

A total of 67 complications occurred during this period, for an overall complication rate of 11.1%. Hoarseness, with or without vocal cord paresis, was the most common complication for each type of surgery, followed by infection. Jugular vein injury, hematoma, and other complications occurred in smaller numbers.

Logistic regression analysis showed that a longer mean duration of surgery was associated with a higher complication rate only in patients receiving full revision surgery (P =.039). No other statistically significant associations were found between risk factors and complications.

A higher percentage of revision and full removal surgeries were associated with surgical complications, compared to primary implantation surgery. Complication rate for implantation surgery was 13.4%, but 21.4% for revision and 27.3% for full removal surgery. No complications were associated with partial VNS system removals.

Three permanent complications occurred (0.5% of the total). None of the complications were cardiac events, nor were any surgery-related deaths noted.

Study limitations included missing retrospective data, potential imprecision in reporting surgery durations, and possible bias given that high-risk patients receiving multiple surgeries could have increased complication rates artificially.

“Based on the results of this study and especially in the light of the complication risk, we advise to reconsider each request for complete removal and discuss the best strategy in a multidisciplinary setting of the epilepsy surgery conference,” the researchers concluded.