The sternothyroid (ST) muscle is closely adherent to the thyroid gland with oblique insertion into the thyroid cartilage. EBSLN passes through the sternothyroid laryngeal triangle with a parallel course deep to the ST muscle.

This study evaluates the transection of the sternothyroid muscle as a key step during thyroidectomy to increase the rate of exposure and visual identification of EBSLN compared to ST muscle retraction as a traditional technique.

The study was conducted on patients eligible for total thyroidectomy, which meets the standard of the ATA Thyroid Guidelines. Preoperative biochemical thyroid function tests and neck ultrasound with FNAC of suspicious nodules confirmed the clinical diagnosis. Patients who had previously undergone neck surgery or irradiation or were preoperatively diagnosed with a vocal cord movement disorder, a vocal cord benign lesion, or speech disorders were excluded from the study. A random number was used to determine the patient group allocation.

Data about patients were gathered via history, examinations, and investigations. The patients were randomized (computer-generated) with the use of an opaque-sealed envelope into two groups; group A: conventional method of thyroidectomy with ST muscle retraction, group B: transection of ST muscle.

The study's primary endpoint was the identification rate of the EBSLN in both techniques. The secondary endpoints included: a comparison of operative time in both techniques as well as anatomical variability of the EBSLN according to Cernea classification, rate of injury of EBSLN, and changes in postoperative voice performance.

Inclusion Criteria:

• eligible for total thyroidectomy
• no previous history of neck surgery or radiation
• no vocal cord pathology
• no voice disorders

Exclusion Criteria:

• not fit for surgery
• previous history of neck surgery or radiation
• vocal cord pathology
• vocal cord movement disorders