Novel application of electromagnetic neuronavigation for guided ventriculoperitoneal shunt placement in toy-breed dogs with hydrocephalus: a preliminary descriptive study

Objective: To describe the feasibility and accuracy of electromagnetic (EM) neuronavigation for intraventricular catheter placement during ventriculoperitoneal (VP) shunt surgery and to summarize a practical registration workflow in toy-breed dogs with hydrocephalus. Animals: 11 client-owned toy-breed dogs diagnosed with hydrocephalus. Clinical Presentation: Medical records from a single referral center were reviewed retrospectively (from September 2019 through May 2024). Dogs were included if they underwent VP shunt placement using EM neuronavigation (StealthStation S8; Medtronic). Dogs were 2 to 9 years old (median, 5 years) and weighed 1.3 to 4.0 kg (median, 2.9 kg). Presenting signs included seizures, head turning, ataxia, and tetraparesis. Results: Hydrocephalus was diagnosed based on clinical signs and MRI. We placed the dynamic reference frame, which served as the patient position reference, in 1 of the following locations: the rostral hard palate, dorsal muzzle, sublingual rostral mandible, or ventral mandible. Accurate catheter tip placement was assessed by postoperative CT. We could confirm the direction and depth of the intraventricular catheter in real time while inserting the catheter during surgery. The anatomical setup of the device enabled accurate navigation between the EM navigation-displayed images and the actual coordinates. Clinical Relevance: The EM navigation system provides excellent guidance for VP shunt surgery in small dogs and has potential applications in various cranial neurosurgical procedures in veterinary medicine.