The use of readily available equipment in a simple method for intraoperative monitoring of recurrent laryngeal nerve function during thyroid surgery: initial experience with more than 300 cases

HYPOTHESIS: An inexpensive and widely applicable technique to monitor recurrent laryngeal nerve (RLN) function during thyroid surgery can be safely implemented. DESIGN: Consecutive sample. SETTING: Single-surgeon academic practice. PATIENTS: Three hundred sixty-three consecutive patients undergoing surgery for thyroid disease in the 18 months from November 1, 1999, to May 31, 2001. INTERVENTIONS: Anesthetic management using laryngeal mask airway and spontaneous ventilation, combined with electrical RLN stimulation and fiberoptic video laryngoscopy to confirm vocal cord response. MAIN OUTCOME MEASURES: Vocal cord response to RLN stimulation, intraoperative anatomic findings, postoperative voice quality, and anesthetic complications. RESULTS: We used the laryngeal mask airway-based technique in 327 cases. Visualization of vocal cords was maintained throughout the surgery in 310 cases (95%). In 10 cases (3%), the branch of the RLN carrying vocal cord function could not be identified until electrical testing was performed. A single inadvertent RLN palsy was seen in 1 of the 17 cases in which vocal cord visualization was lost during the procedure (0.03% overall). Upper airway obstruction occurred in 16 (5%) of 327 attempted procedures, requiring tracheal intubation in 3 (1%). No further complications regarding airway management were seen. Pneumothorax was observed in 5 cases (2%), each of which resolved without chest tube placement. CONCLUSIONS: This technique can be applied to thyroid surgery as a safe means of managing the airway. It is associated with an ability to test RLN function at will in more than 95% of cases using readily available equipment.