Hypoglossal nerve monitoring, a potential application of intraoperative nerve monitoring in head and neck surgery

Intraoperative nerve monitoring (IONM) has many applications in different surgical fields. In head and neck surgery, IONM has been used to perform surgery of the parotid, thyroid and parathyroid glands, preserving the facial and recurrent nerves. However, hypoglossal nerve neuromonitoring has not been addressed with such relevance. A retrospective review of surgeries performed on patients with special tongue and floor of mouth conditions was undertaken to examine the indications that prompted its use. Particular attention was given to the pathology, intraoperative findings and the final outcome of each patient. Four patients, aged between 6 years and 68 years, with complex oral tongue and floor of mouth lesions were reviewed. Three patients were male, aged 22 years and younger, and two of these patients had oral tongue cancers with previous surgery. Oral tongue and neck conditions are challenging since the functions of the hypoglossal nerve are put at risk. The use of IONM technology allowed us to preserve nerve functions, speech and swallowing. Although IONM of the hypoglossal nerve is not a common indication in tongue and floor of mouth lesions, under special conditions its application can be extrapolated to challenging surgical cases, like the ones described.