Introduction: Vocal cord paralysis is a serious and much feared complication related to the implantation of vagus nerve stimulators. There is strong evidence supporting the effectiveness of vagus nerve stimulation (VNS) in reducing the frequency and severity of seizures in many patients with epilepsy and VNS is also reported to have efficacy in the treatment of other disorders such as depression and intractable hiccups. The coils which secure the stimulator lead to the vagus nerve are available in two inner diameters, 2 mm and 3 mm. This investigation tests the hypothesis that vocal cord paralysis following implantation of vagus nerve stimulators occurs more frequently with leads having the smaller 2 mm coils than those with 3 mm coils.

Methods: All data used in this investigation were collected, as mandated by the FDA, by the manufacturer of vagus nerve stimulators and were made available without restrictions for analysis by these authors. The data reflect all initial device implantations in the United States for 1997 through 2012.

Results: Vocal cord paralysis was reported in 193 of 51,882 implantations. In patients 18 years of age and older, the rate of paralysis was 0.26% when the stimulator leads had coil diameters of 3 mm and the rate was 0.51% when the leads had 2 mm coils (p < 0.05). Across all age groups the rate of vocal cord paralysis increased with age at implantation for leads having 2 mm coils (Figure 1).

Conclusions: Vocal cord paralysis was associated, in patients 18 years of age and older, with implantation of vagus nerve stimulators having leads with coils of 2 mm diameter at almost twice the rate as those with coils of 3 mm diameter. The risk of vocal cord paralysis increases with age at implantation.

Patient Care: This study shows that in patients 18 years of age or greater the rate of vocal cord paralysis after vagus nerve stimulator placement is significantly higher. This should be considered when choosing a lead size to minimize this risk.

Learning Objectives: By conclusion of this session, participants should be able to 1)discuss the prevalence of vocal cord paralysis associated with vagus nerve stimulator placement over all, 2) discuss the difference in rates of vocal cord paralysis between the two different vocal cord stimulator lead sizes, 3) Discuss the difference in vocal cord paralysis among different age groups

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