Complications and safety of vagus nerve stimulation: 25 years of experience at a single center.

OBJECTIVE The goal of this paper was to investigate surgical and hardware complications in a longitudinal retrospective study. METHODS The authors of this registry study analyzed the surgical and hardware complications in 247 patients who underwent the implantation of a vagus nerve stimulation (VNS) device between 1990 and 2014. The mean follow-up time was 12 years. RESULTS In total, 497 procedures were performed for 247 primary VNS implantations. Complications related to surgery occurred in 8.6% of all implantation procedures that were performed. The respective rate for hardware complications was 3.7%. Surgical complications included postoperative hematoma in 1.9%, infection in 2.6%, vocal cord palsy in 1.4%, lower facial weakness in 0.2%, pain and sensory-related complications in 1.4%, aseptic reaction in 0.2%, cable discomfort in 0.2%, surgical cable break in 0.2%, oversized stimulator pocket in 0.2%, and battery displacement in 0.2% of patients. Hardware-related complications included lead fracture/malfunction in 3.0%, spontaneous VNS turn-on in 0.2%, and lead disconnection in 0.2% of patients. CONCLUSIONS VNS implantation is a relatively safe procedure, but it still involves certain risks. The most common complications are postoperative hematoma, infection, and vocal cord palsy. Although their occurrence rates are rather low at about 2%, these complications may cause major suffering and even be life threatening. To reduce complications, it is important to have a long-term perspective. The 25 years of follow-up of this study is of great strength considering that VNS can be a life-long treatment for many patients. Thus, it is important to include repeated surgeries such as battery and lead replacements, given that complications also may occur with these surgeries.