Superior approach to the inferior laryngeal nerve in thyroid surgery: anatomy, surgical technique and indications.

Goals Of The Study: To describe the anatomical bases of the surgical access to the higher part of the thyroid lobe, with first location of the inferior laryngeal nerve at its laryngeal penetration, to discuss the advantages and disadvantages of this surgical technique and to determine the operational indications.

Population And Method: A prospective study of surgical anatomy performed over a period of 18 months was conducted. A total of 25 (22 women and 3 men) patients with cervicothoracic goitre underwent total thyroidectomy. Thyroid lobectomies were performed using the technique of "capsular thyroidectomy", with first location and complete dissection of the inferior laryngeal nerve. A neurostimulator was systematically used for the location of the inferior laryngeal nerve and also the external laryngeal nerve.

Results: The first detection of the inferior laryngeal nerve at the top of the thyroid lobe was positive in 49/50 cases. A superior parathyroid gland was found in 75% of cases and an inferior parathyroid gland in 37.5% of cases. The external laryngeal nerve was stimulated and respected in 12,5% of cases. No voice trouble, no laryngeal palsy and no definitive hypoparathyroidism occurred after surgery.

Conclusion: Safeguarding of the inferior laryngeal nerve is the principal and obligatory stake in thyroid surgery. Locating the inferior laryngeal nerve at the level of its laryngeal penetration at the superior pole of the thyroid region is necessary in cases of particular situations: huge cervicothoracic goitres, re-operative procedures and various anatomical variations. The use of a neurostimulator secures this technique.