Clinical usefulness of nerve integrity monitoring (NIM) for the removal of upper neck neurinomas

Findings of previous studies have shown that the identification of the responsible nerve when removing a parapharyngeal space neurinoma and the preservation of nerve functions are difficult. These processes are however crucial for both surgeons and patients during parapharyngeal space neurinoma surgery. The Nerve Integrity Monitoring System (NIM-Response® 3.0-, Medtronic, USA) has been recognized as a useful tool for surgery of parotid and thyroid glands, and for detecting and preserving the facial nerve and recurrent laryngeal nerve or superior laryngeal nerve. In the present study, we used the NIM system in the treatment of 3 cases of parapharyngeal space neurinomas. Two vagal neurinomas were successfully removed and the vagal nerve function was preserved by an intracapsular resection of the neurinoma using the NIM system, and one sympathetic neurinoma was resected for the contamination of the nerve in the tumor: the sympathetic nerve was repaired with a greater auricular neuronal graft. The NIM system showed good results in identifying the responsible nerve and assisting with preserving the functions of both the responsible and surrounding nerves in these 3 parapharyngeal space neurinoma surgeries.