Functional Nerve Preservation in Extracranial Head and Neck Schwannoma Surgery

Abstract

The strategy used here demonstrated a method of diagnosis and nerve preservation surgery for extracranial schwannomas. Nerve functionality was preserved in all vagus schwannoma cases. However, preservation of nerve function in sympathetic nerve schwannoma cases remains problematic and needs further investigation.

A novel approach to neurologic function sparing surgical management of vagal schwannomas: Continuous intraoperative nerve monitoring of the laryngeal adductor reflex

“…This can be performed intermittently, as in this case series, or continuously. 9,10 The other measures the amplitude of the LAR response, which is distinct from all CMAP monitoring techniques. This can be done continuously.…”

Cervical Sympathetic Chain Schwannoma Masquerading as a Vagus Nerve Schwannoma Complicated by Postoperative Horner’s Syndrome and Facial Pain: A Case Report

“…FBS presents with pain radiating throughout the jaw elicited on the initial bite of each meal that resolves with ensuing mastication [ 13 ]. The pathophysiology of FBS is likely due to sympathetic nerve damage [ 14 , 15 ]. In this case, the dissociation of pain from meals and mastication distinguishes it from FBS.…”

Vagal schwannomas of the head and neck: A comprehensive review and a novel approach to preserving vocal cord innervation and function

“…In the case of vagal schwannomas, nerve stimulation during tumor excision can help to distinguish the location of the nerve fibers running over the tumor surface, thereby preserving functional fibers that innervate the larynx and minimizing postoperative morbidities including dysphonia, dysphagia, and a permanent risk of aspiration . Conventional IIONM can also be used to identify or confirm the nerve of origin of a tumor when other diagnostic studies are inconclusive . With sensors placed in muscles, electrical stimulation can be applied to the tumor through a stimulating electrode, and muscle activity can be recorded.…”

“…If the tumor is on a motor nerve, a muscular response will be observed at the sensor electrode. However, if the tumor is on a sensory nerve, stimulation of the tumor will not produce a muscular response …”

“…As previously mentioned, IIONM has been deemed useful in cases of vagal schwannoma to determine the precise location of the functional neural fibers within the tumor . This enables the tumor capsule to be entered without injuring functional fibers.…”