[Anatomical variations of external laryngeal nerve and thyroid chirurgical: about 32 dissections]. / Variations anatomiques du nerf laryngé externe et chirurgie thyroïdienne: à propos de 32 dissections.

AIMS AND SCOPE: The aim of this study is to improve our knowledge about external laryngeal nerve anatomical and its variations at the superior extremity of thyroid and to estimate the risk of its injury during surgical thyroid procedures. MATERIALS AND METHODS: Anatomical, descriptive study performed in the service of pathology and forensic medicine of the university hospital of Treichville. Sixteen fresh adults cadavers have been dissected (32 dissections of the superior thyroid pedicle). RESULTS: We found the external nerve laryngeal and the higher thyroid artery in 100% of cases. The 32 dissected nerves were born on the level of the greater horn of the hyoid bone. The situation of the external laryngeal nerve in relation to the branches of the superior thyroid artery were: (1) in 75% of cases non-intermingled; (2) in 25% of cases intermingled. The risks of lesions of the external laryngeal nerve are: (1) 25% overall; (2) 12,5% on the right; (3) 37,5% on the left. CONCLUSION: The risk of injury of the external laryngeal nerve during thyroid surgery procedure is never zero. It is more important on the left side.