Operative and technical complications of vagus nerve stimulator implantation

BACKGROUND: The treatment of refractory epilepsy by vagus nerve stimulation (VNS) is a well-established therapy option for patients not suitable for epilepsy surgery and therapy refractory depressions. OBJECTIVE: To analyze surgical and technical complications after implantation of left-sided VNS in patients with therapy-refractory epilepsy and depression. METHODS: One hundred five patients receiving a VNS or VNS-related operations (n = 118) from 1999 to 2008 were investigated retrospectively. RESULTS: At the time of operation, 84 patients were younger than 18 years, with a mean age of 10.5 years. Twenty (19%) patients had technical problems or complications. In 6 (5.7%) patients these problems were caused by the operation. The device was removed in 8 cases. The range of surgically and technically induced complications included electrode fractures, early and late onset of deep wound infections, transient vocal cord palsy, cardiac arrhythmia under test stimulation, electrode malfunction, and posttraumatic dysfunction of the stimulator. CONCLUSION: VNS therapy is combined with a wide spread of possible complications. Technical problems are to be expected, including electrode fracture, dislocation, and generator malfunction. The major complication in younger patients is the electrode fracture, which might be induced by growth during adolescence. Surgically induced complications of VNS implantation are comparably low. Cardiac symptoms and recurrent nerve palsy need to be taken into consideration.