Is the superior laryngeal nerve really safe when using harmonic focus in total thyroidectomy? A prospective randomized study.

Background: Harmonic focus (HF) was introduced in thyroid surgery in an effort to reduce operation time and complications.

Objective: The present study aimed to compare function of superior laryngeal nerve and incidence of other postoperative complications in total thyroidectomies using HF and conventional ligation (CL).

Methods: The trial is a randomized single-center, single-blinded study. Patients aged ≥ 18 years scheduled for total thyroidectomy were considered for participation. An ultrasonic dissector was used for coagulation and cutting in the HF group, while the standard technique was used in the CL group. Demographic, surgical data, and complications were recorded. Data were analyzed using SPSS for Windows.

Results: Of 244 eligible patients, data of 206 patients who completed the study were analyzed. The groups were similar in terms of age, sex, and indication for operation. The mean operative time in the HF group was significantly shorter than that in CL group (p=0.01). Drain necessity, duration of drainage, duration of postoperative hospitalization, and the incidence of postoperative complications was similar in the groups (p>0.05). The external branch of the superior laryngeal nerve and recurrent laryngeal nerve palsy were noted in three and two patients in the HF group and in two and one patients in the CL group at 6 months.

Conclusion: To the best of our knowledge, this is the first study comparing conventional technique with HF in total thyroidectomy, focusing on the function of the external branch of the superior laryngeal nerve using laryngostroboscopy; results showed that HF is as safe as the conventional technique.