Surgical anatomy of the recurrent laryngeal nerve revisited

Previous anatomic studies of the recurrent laryngeal nerves (RLNs) have described the variability in the course of the RLN. The anatomy of the nerve appears more constant along its distal segment near the cricothyroid joint, which is our surgical approach to the initial identification of the nerve. Understanding the topographical anatomy of the nerve in this region facilitates quick and safe nerve identification. The surgical topographical anatomy of the nerve in this region has not been studied in detail, which is the focus of this study.

A total of 278 RLNs in 190 patients were dissected during thyroidectomy and/or parathyroidectomy. The course of the nerve was recorded, paying particular attention to the directional course along its distal portion. The angle in which it coursed in relationship to a line paralleling the tracheoesophageal groove was determined.

All 278 nerves were identified. Seventy-eight percent of the right-sided nerves coursed between 15 and 45 degrees, and 77% of the left-sided nerves coursed between 0 and 30 degrees. It appears that the nerve is more likely to travel at a more obtuse angle with right-sided RLNs and in patients with a low-lying cricoid. There was no permanent postoperative RLN palsy, and the incidence of temporary palsy was 1%.

Approaching the nerve along its distal portion is safe and effective. The surgical topographical anatomy in this region is described in detail. Some of the potential advantages of identifying the nerve more distally include less chance of disrupting the blood supply to the inferior parathyroid gland, dissection along a shorter portion of the nerve, and less variability of the nerve.