Safety and Management of Magnetic Interactions Between Ipsilateral Cochlear Implantation and Programmable Ventriculoperitoneal Shunts

Objective: To describe 2 cases of ipsilateral programmable ventriculoperitoneal shunt placement and cochlear implantation, and provide recommendations on the specific risks and perioperative considerations related to magnetic interactions between devices. Patients: An 82 and 83-year-old male with a history of normal pressure hydrocephalus and 2 different types of programmable ventriculoperitoneal shunts, one of which was considered locking and the other non-locking. Intervention (s): Ipsilateral cochlear implantation with and without preoperative ex vivo magnet interaction testing. Main outcome measure(s): Occurrence or non-occurrence of programmable ventriculoperitoneal shunt setting change secondary to cochlear implant magnetic interaction. Results: In case 1, the patient’s non-locking valve setting was found to be significantly altered from baseline at 6 months postoperatively, prompting revision to a shunt with a locking mechanism, allowing resumption of cochlear implant use. In case 2, there was no interaction between the locking valve and cochlear implant observed during preoperative ex vivo device testing or through postoperative monitoring. Conclusions: Cochlear implantation in patients with programmable ventriculoperitoneal shunts is feasible but requires careful planning. In addition to avoiding direct magnetic overlap and verifying valve function before and after surgery, cochlear implant surgeons should consider avoiding ipsilateral cochlear implantation in the setting of a non-locking programmable ventriculoperitoneal shunt valve.