[Vagus nerve stimulation therapy in epilepsy patients: long-term outcome and adverse effects: a retrospective analysis]

Abstract

Background: Vagus nerve stimulation (VNS) is one of the numerous stimulation procedures used in the treatment of neurological diseases in which there has been growing interest in recent years. Since 1988 it has been frequently used in the therapy of epilepsies but the mechanism of action is still unknown. It is considered to be low in adverse effects.

Topics: Decision-making process on VNS therapy as well as long-term outcome and adverse effects.

Method: Retrospective analysis of all 62 patients treated over a long period by VNS in the Epilepsy Center of the University Hospital of Freiburg (Germany) from 1 August 2002 through 4 January 2011.

Outcome: the results show that 2 out of 62 patients became seizure-free under VNS therapy while maintaining the already existing anti-ictal medication and 4 more patients under VNS plus dosage increase of the already existing medication and/or new medication. However, in 34 out of 62 patients VNS therapy did not improve the seizure situation. Adverse effects: VNS is not as low in adverse effects as is generally considered. Only 9 out of 62 patients did not show any adverse effects and on the other hand severe, even life-threatening adverse effects also occurred.

Conclusion: Patients undergoing VNS therapy have to be carefully checked for possible adverse effects, not only at the beginning of VNS therapy but also in the long-term course. These results have to be considered in the cost-benefit analysis of this treatment.