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

Abstract

<jats:sec> <jats:title>OBJECTIVE</jats:title> <jats:p>The goal of this paper was to investigate surgical and hardware complications in a longitudinal retrospective study.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>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.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>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.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>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.</jats:p></jats:sec>

Hyperbaric Oxygen Therapy as Adjuvant Treatment for Hardware-Related Infections in Neuromodulation

“…We found that HBOT was an efficient and safe adjuvant to antibiotics in the treatment of hardware-related infections, which allowed continued neuromodulation treatment and preservation of hardware following 12 out of 14 (86%) infection events in 10 out of 12 (83%) patients. This is a remarkable improvement in comparison to the outcomes in previous reports [7, 23-31], where hardware removal was undertaken for infection resolution in almost every instance (see Table 3 for comparison). Our results agree with the benefit of adjuvant HBOT reported in other neurosurgical infections such as cranial bone flap osteomyelitis [12, 32, 33] and spinal implants [34].…”

The role of vagus nerve stimulation in refractory epilepsy

“…Whereas studies report rates of 1% to 5% of hardware malfunction 4 , these estimates are highly variable. Révész et al 40 published a 3% incidence of lead breakage, noticed mainly by the increase of seizure frequency, as not all fractures are identified on imaging screening. Infection rates vary from 3% to 7% and, although generally treated with intravenous antibiotics and explantation of the device, some have described success managing these patients exclusively with oral antibiotics.…”

“…When comparing patients younger and older than 12 years, no significant difference in efficacy or complication rate was demonstrated after five years of follow-up in 141 patients 39 , although some reported increased infection rates in children 40 . Predictors of response have not been completely clarified, although some elements may have a prognostic value.…”

Neuromodulation in refractory epilepsy: Brazilian specialists consensus

“…The adverse effects are rather low at about 2%, usually occuring during the "on" phase of stimulation, and have a tendency to decrease over time. The most common complications are postoperative hematoma, infection, and vocal cord paralysis 7 . Voice hoarseness, cough and paresthesias can also occur 7 .…”

“…Currently, more than 100,000 VNS devices have been implanted in more than 80,000 patients 7 . In Brazil, from January 2001 to March 2016, 665 VNS devices were implanted (Politec Health, personal communication).…”