Introduction: 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.

Materials and methods 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.

Results 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).

Conclusion We report the fourth case in the literature, a case of permanent Horner.

Notes: 

1. Pediatric and Functional Neurosurgery, Padua University Hospital, Padua, Italy
2. Pediatric Neurology and Neurophysiology, Padua University Hospital, Padua, Italy
3. Neurology, Padua University Hospital, Padua, Italy
4. Epilepsy Unit, Villa Santa Maria SCS, Tavernerio, Como, Italy
5. Neuroscience Department, University of Padua, Via N. Giustiniani 5, Padua 35128, Italy