Anatomical Course of the Recurrent Laryngeal Nerve and Its Relationship with the Surrounding Structures: A Prospective Surgical Study

Background: Despite all the advances in thyroid surgery, thyroidectomy remains an operation open to complications due to the recurrent laryngeal nerve (RLN) which the thyroid gland is closely surrounded by. This study aims to investigate the anatomical relationship of the RLN with the surrounding structures and define the relationships between these structures. Methods: In this prospective study, the relationship of the RLN with the surrounding anatomical structures, which consist of Berry’s ligament, inferior thyroid artery, tracheoesophageal groove, and the inferior constrictor muscle, and the presence of extralaryngeal branching were evaluated during thyroid surgery performed on 91 patients. Results: A total of 151 thyroid lobectomies were performed, which included 75 right and 76 left lobectomies. One patient presented a nonRLN on the right side, and of the remaining 150 thyroid lobectomy materials, 40 (26.7%) demonstrated a nerve passing anterior to, 93 (62%) passing inside, and 17 (11.3%) passing posterior to the tracheoesophageal groove. Evaluation of the relationship between the nerve and Berry’s ligament revealed that the nerve was located on the lateral side of Berry’s ligament in 114 lobectomies (76%). The nerve passed anterior to the inferior thyroid artery in 29 lobectomies (19.3%), between its branches in 17 (11.3%), and posterior to the artery in 104 (69.4%). The nerve was found to penetrate the crico-pharyngeal part of the inferior pharyngeal constrictor muscle in 8 lobectomies (5.3%), while it entered the larynx immediately under the muscle fibers in 142 (94.7%). The RLN demonstrated branching before entering the larynx in a total of 9 cases (6%). It was determined that the relationship of the nerve and the associated anatomical structures did not cause a significant difference in either side. Conclusion: None of the anatomical parameters investigated in this study demonstrated a constant pathway associated with the anatomical course of the nerve.