Surgical explantation of a vagal nerve stimulator according to the magnetic resonance imaging protocol
Abstract
Aim: An overview of MRI in patients with implanted vagal nerve stimulator (VNS) and the method of surgical explantation of VNS, reflecting the MRI protocol allowing the subsequent MRI examination without significant limitations. Patients and methods: MRI can also be safely performed in patients with the implanted VNS device.
Head examination and body examination caudally from Th8 can be performed, but only local radiofrequency coils must be used. Before the MRI, the VNS system must be reprogrammed.
If the patient has an explanted generator and the larger part of the electrode, the MRI of the entire body can be performed with any common MRI setting. This applies to a situation where after the explantation there is only a 2-cm part of the electrode left cor responding to the portion of the electrode on the vagal nerve with fixation anchors.
Results: From June 2016 to June 2018, we explanted a VNS with this approach in six patients. Post-operative course of all patients was without complications.
Post-operative control was performed using neck X-ray and CT 3D imaging. Imaging methods showed that the remainder of the electrode on the vagal nerve electrode was <= 2 cm.
Post-operatively, patients did not have swallowing difficulties, hoarseness or voice changes. Four patients have subsequently already undergone MRI without any difficulties or complications.
Conclusion: Surgical explantation of VNS according to the MRI protocol, leaving part of the electrode on the vagal nerve and omitting the complete preparation of the entire electrode on the nerve, reduces the risk of complications and shortens the duration of the operation. The patient can afterwards safely undergo the MRI of the entire body without any limitations in normal technical settings.