Intra-operative nerve monitoring does not reduce the incidence of recurrent laryngeal nerve injury in first-time thyroid surgery when performed by an experienced thyroid surgeon

Background: Recurrent laryngeal nerve injury is a feared complication of thyroid surgery, carrying significant morbidity including hoarseness, dysphagia, and respiratory distress. Direct visualization of the nerve during surgery is the standard of care for preventing injury. Intra-operative nerve monitoring (IONM) is an adjunct utilized to decrease the risk of nerve injury, with rising popularity over the past two decades. At present, its exact role is controversial. Some studies advocate routine use, while others suggest that it only adds benefit to select complex cases. The present study is a single-center, retrospective analysis to determine whether the use of IONM significantly prevents injury to the recurrent laryngeal nerve during first-time thyroid surgery, as compared to the current practice of direct nerve visualization. Methods All patients undergoing thyroid surgery at Wellspan York Hospital and its affiliated outpatient surgical center from July 2018 until March 2021 were included in the study. For nine months of the study, IONM was routinely used for first-time thyroid surgery. For the remaining period, direct visualization alone was used for first-time surgery, and IONM was used only selectively for ipsilateral re-operative thyroid surgery. All data was acquired from The Collaborative Endocrine Surgery Quality Improvement Program, a national endocrine surgical database. We compared nerve injury rates across the three groups of patients. Results 377 patients who had thyroid surgery were identified with a total of 591 nerves at risk for injury. Six patients suffered inadvertent nerve injury, for an injury rate of 1.02%. In the group undergoing first-time thyroid surgery with direct visualization alone, four nerves out of 450 (0.89%) were injured. In the group with IONM routinely used for first-time surgery, there was one nerve injury out of 120 (0.83%). For patients with history of previous ipsilateral endocrine surgery with selective nerve monitoring, one injury occurred in a total of 13 at-risk nerves (7.69%). Conclusions The use of IONM as compared to direct identification and photo documentation of the recurrent laryngeal nerve offered no significant advantage in preventing injury. Additionally, re-operative cases have higher incidence of nerve injury, and IONM may be helpful in improving safety in these cases.