Role of Intraoperative Nerve Monitoring During Parathyroidectomy to Prevent Recurrent Laryngeal Nerve Injury

Abstract

Injury to the recurrent laryngeal nerve (RLN) is a well known, though less frequent, complication of parathyroid surgery. In recent years, the use of intraoperative nerve monitoring (IONM) has gained popularity amongst surgeons when operating on thyroid gland; however, its utilization in parathyroid surgery is not established. This trend continues to rise, despite multiple studies documenting no statistically significant difference that IONM decreases the incidence of RLN injury. Most surgeons use this technology as an adjunct to visualization alone for identification of RLN. The purpose of this review is to discuss the possible role of IONM in parathyroid surgery with regards to the accuracy, efficacy, and recent trends in the utilization of this technology. There is insufficient evidence that IONM reduces the risk of RLN injury in parathyroidectomy. Although IONM may decrease the likelihood of nerve injury by helping to identify and map the RLN during thyroidectomy, we did not find studies exclusive to parathyroid surgery to see if its use can be supported for parathyroidectomy. Despite this lack of evidence, we believe that IONM is a promising adjunct to visualization alone in detecting nerve structures during neck dissection, but more clinical trials are warranted to establish its role in preventing nerve injury in parathyroid surgery.

Keywords: nerve monitoring; nim; parathyroid surgery; recurrent nerve injury; vocal cord paresis.

Figure 1. Anatomical Distribution of Recurrent Laryngeal Nerve in the Neck

Figure 2. IONM Patient and Equipment Setup

Reproduced and modified with permission from Randolph GW: Surgical anatomy of recurrent laryngeal nerve. (Courtesy Randolph GW (Ed). In: Surgery Thyroid and Parathyroid Glands. 2003, Saunders, Philadelphia, PA). ETT: endotracheal tube; IONM: intraoperative nerve monitoring; NIM: Nerve Integrity Monitor

Figure 3. The Medtronic XoMed Tube Nerve Integrity Monitor (NIM)

ETT: endotracheal tube