There has been a significant steady increase in the number of thyroid surgeries performed annually in the United States,1 escalating existing pressures to maintain a low rate of complications in this surgical setting.
Recurrent laryngeal nerve (RLN) injury is an unfortunate complication of thyroid surgery. Unilateral vocal cord paralysis may create changes in voice, which if severe may impose vocational limits or loss, lead to dysphasia, or culminate in pulmonary complications due to aspiration.2 Life-threatening loss of airway, with a need for tracheostomy, is the consequence of bilateral vocal cord paralysis.3
The external branch of superior laryngeal nerve (EBSLN) is vulnerable to injury when dissecting the superior pole of the thyroid gland. Injury to EBSLN may cause paralysis of cricothyroid muscle, which is difficult to detect by endoscopic means. Although EBSLN injuries affect the voice variably and may be minor, any such deficit is potentially devastating to professional vocalists and others whose livelihood is similarly susceptible.
Intraoperative visual identification of nerves is the method traditionally used to avoid RLN and EBSLN injuries during thyroid surgery. Still, a functional nerve cannot be assured by gross visualization alone. Neural monitoring adds a novel functional dynamic to customary protocol. We do not consider the use of intraoperative nerve monitoring as the standard of care to decrease the risk of possible complications related to the nerve injury. Herein, the benefits of intraoperative nerve monitoring are discussed, detailing a multifaceted approach that extends beyond basic visual inspection.
Intraoperative nerve monitoring (IONM) technologies were first reported in 1965 by Shedd and Durham4 as a novel method to reduce the risk of RLN injury. In 1970, the use of intramuscular vocal cord electrodes was described by Basmajian.5 In addition, there is a long history of IONM in a variety of head-and-neck and skull-base procedures, where such monitoring is associated with improved outcomes.
Although visual identification of RLN decreases the rate of permanent RLN injury, it remains the most common source of medicolegal litigation following thyroid surgeries.5 Due to the morbidity inflicted, awards to plaintiffs for bilateral vocal cord paresis may amount to millions of dollars.3 However, there is no evidence that intraoperative nerve monitoring is associated with a decreased risk of RLN injury. Dralle et al6 suggested that conducting a study with the typical rates of nerve injury would need millions of patients to be statistically powerful.
It is prudent to maintain detailed records of pre- and postoperative patient visits, including pivotal discussions. Preoperative emphasis on RLN injury as a potential complication is especially important, as well as documenting this risk clearly in informed consent. If IONM is used, operative reports should address patient status and nerve stimulation characteristics at the close of surgery. The American Academy of Otolaryngology—Head and Neck Surgery (AAO-HNS) recommends treating any complications ...