A Rare Complication of Vagus Nerve Stimulation Surgery: the Horner Syndrome. Case Report and Systematic Review

Vagus nerve stimulation (VNS) is a therapy used for drug-resistant epilepsy, refractory status epilepticus and treatment-resistant depression. VNS can reduce seizure severity and frequency, improving quality of life. It is generally well tolerated, with rare complications, which can be early (surgical) or late (device-related or stimulation-related). Common side effects include vocal cord issues, cough, and infections. We present Horner syndrome as a rare complication of VNS caused by damage to the sympathetic innervation of the ipsilateral eye and characterized by ptosis, miosis and rarely anhidrosis. This was a case report and systematic review of the available literature according to PRISMA guidelines. The examined databases are Medline/PubMed, Scopus and Web of Science. A fourteen-year-old girl with drug-resistant epileptic encephalopathy and lissencephaly underwent VNS. Clinical signs of Horner syndrome appeared a few hours later. Our systematic review of the literature collected only three cases of Horner syndrome following VNS surgery out of 178 patients studied (one case report and two retrospective studies included in review). We report the fourth case in the literature, a case of permanent Horner.