Evaluation of MRI-resistance of the Codman Certas Plus shunt valve in vivo

Introduction: The Codman Certas Plus shunt valve was introduced in 2015. It has 8 different settings and was designed to resist the magnetic forces of 3 T MRI to avoid unintentional setting changes. In‐vitro testing by the company has shown this to be the case. However, post‐MRI check of the shunt setting is still recommended by the manufacturer. No study has yet shown the MRI‐resistance of Certas Plus valves in a clinical setting. Methods: 35 iNPH‐patients (18 m/17f), median age 78(68‐85) years, were operated with a Codman Certas Plus valve in this single‐centre study. Valve setting was preoperatively randomized to 4 or 8 and blinded to the surgeon, patient and valve setting examiner. A 3 T MRI was performed 24‐48 h postoperatively and valve setting was checked afterwards. Patients with setting 8 were adjusted to 4. Another 3 T MRI was done after 3 and 12 months with check of valve setting. Results: A total of 68 3 T MRI are done of 35 Codman Certas Plus valves so far. All (100%) checked valve settings are accordance with the intended setting. There has been no unintentional setting change. Conclusions: The MRI‐resistance to unintentional valve setting changes of the Codman Certas Plus shunt valve is reliable in a clinical setting. This is in accordance with the experimental study done by the manufacturer. This has led to our institution abandoning the post‐MRI check of the shunt setting making 3T MRI of these patients possible in regional hospitals without shunt adjustment tool kits and knowledge of the procedure.