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Nerve Monitoring System Can Help Identify Functional Separation between Branches of Hypoglossal Nerve

by Samara E. Kuehne •

Could a selective nerve integrity monitoring (NIM) system aid in placement of the cuff electrode in selective upper-airway stimulation?

BOTTOM LINE
Selective nerve monitoring is able to identify the protruding and stiffening fibers of the hypoglossal nerve, and therefore facilitates the precise inclusion and exclusion of nerve fibers during intraoperative placement of the stimulation cuff electrode.

Background: Unilateral therapeutic electrical stimulation of the hypoglossal nerve is feasible and a potential therapeutic option for obtructive sleep apnea. The desired target for success therefore seems to be the selective stimulation of the hypoglossal nerve fibers, which are responsible for the protrusors and stiffeners while excluding the retractors, thereby achieving unhindered protrusion of a stiffened tongue. The postoperative tongue motions in upper airway stimulation are associated with therapy outcome. The stimulation cuff electrode placement on the hypoglossal nerve for selective muscle recruitment seems to play an important role in the mechanism of action. The aim of this study was to investigate whether intraoperative selective nerve monitoring can reliably identify the protruding and stiffening fibers of the hypoglossal nerve to facilitate precise placement of the stimulating cuff electrode.

Study design: Single-center, prospective clinical trial.

Synopsis: The study included 20 patients who received a selective upper-airway stimulation system (Inspire Medical Systems, Maple Grove, Minn.) between July 2014 and June 2015 and who were implanted using a NIM system. The tongue motions were recorded during surgery and two months postoperatively from the transoral view and by transnasal endoscopy All patients exhibited consistent protrusion at tongue front and tongue base. The nerve monitoring system helped to place the cuff electrode around the protrusion and stiffening branches, while excluding the retractor branches of the hypoglossal nerve.

Disclosures: C. Heiser and B.T. Woodson are study investigators and consultants for Inspire Medical Systems. L. Lozier is an employee of Inspire Medical Systems.

Citation: Heiser C, Hofauer B, Lozier L, Woodson BT, Stark T. Nerve monitoring–guided selective hypoglossal nerve stimulation in obstructive sleep apnea patient. Laryngoscope. 2016;126:2852–2858.