Intraoperative Ansa Cervicalis Nerve (ACN) Stimulation (ACS)

Recently published data suggest that stimulation of the infrahyoid strap muscles increases pharyngeal patency in patients with obstructive sleep apnea, but the innervation of these muscles by the ansa cervicalis is variable. The investigators propose a study examining the anatomic variation of the ansa cervicalis and the effect of neurostimulation on muscle recruitment.

This is a single-arm physiology study. Consenting patients undergoing neck dissection (ND) for cervical lymphadenectomy of level IV will undergo dissection of the ansa cervicalis nerves to the infrahyoid strap muscles. Per routine care, a large incision is made across the neck to provide surgeons access to the cervical lymph nodes for extirpation. During this dissection, the branch(es) of the ansa cervicalis nerve plexus descending from the loop of the plexus and innervating the infrahyoid strap muscles (the "common trunk") are dissected uni- or bilaterally. For this study, measurements and photos/videos of the common trunks will be taken. An electrode will be placed on one or both common trunks to stimulate infrahyoid muscles.

All patients who meet eligibility will undergo uni- or bilateral neck dissection and other indicated procedures for management of head and neck cancer and will have measurements and photos/videos of the common trunks taken. An electrode will be placed on one or both common trunks to stimulate infrahyoid muscles.

Consented patients who meet eligibility will have a surgical procedure for management of head and neck cancer, with dissection and exposure of the relevant anatomic structures as part of regular clinical care.

A nerve stimulator device will be used in this study as a research tool to investigate whether a future (currently nonexistent) medical device might be able to stimulate desired infrahyoid musculature in a therapeutic manner.

Anatomic measurements of the length, diameter, and comformation of the common trunk of the ansa cervicalis to the sternothyroid muscle and it's dependent branches, measured in mm with a flexible ruler.

The amount of caudal movement of the thyroid cartilage and hyoid bone with stimulation of the common trunk of the ansa cervicalis to the sternothyroid muscle and it's dependent branches, measured in mm with a flexible ruler.

Anatomic confirmation of the common trunk of the ansa cervicalis to the sternothyroid muscle and it's dependent branches, documented with photography.

Inclusion Criteria: Adult patient (≥18 years old). Scheduled for uni- or bilateral neck dissection (BND) for cervical lymphadenectomy of level IV and other indicated procedures for management of head and neck cancer. Exclusion Criteria: Unable to consent for research due to a pre-existing neurologic condition as determined by PI. Unable to consent for research due to language barriers. History of prior neck surgery with transection of the infrahyoid strap muscles as determined by clinical history.