Harmonic scalpel is a new surgical instrument. Its use has been recommended in patients submitted to total thyroidectomy. Few randomized controlled trials has been published. However they had small sample sizes, used intermediate outcomes and included different surgical procedures.

Our objective is to asses the use of Harmonic scalpel in patients submitted to total thyroidectomy using surgical complications, operative time, drainage volume, postoperative pain, length of stay and costs as outcomes. Our hypothesis is that Harmonic scalpel decreases operative time,drainage volume, postoperative pain, length of stay and costs without increasing surgical complications

This is a multicentric open phase IV randomized controlled trial comparing patients submitted to total thyroidectomy comparing standard surgical procedure versus Harmonic scalpel assisted procedure. Adult patients with benign or malignant thyroid disease and normal function will be included. Patients with giant goiter, hyperthyroidism, non differentiated thyroid carcinoma, locally invasive tumors, neck dissection, previous neck radiotherapy or chemotherapy, video assisted surgery and severe comorbidities will be excluded. calculated sample size was 280 patients. Outcomes will be assessed by an independent monitor. All centers will made a previous standardization of surgical procedures.

Inclusion Criteria:

• Adult (>18 y/o)
• Benign or malignant thyroid disease
• Proposal of total thyroidectomy
• Normal thyroid function

Exclusion Criteria:

• Giant goiter
• Hyperthyroidism
• Non differentiated thyroid carcinoma
• Locally invasive tumors
• Neck dissection as a part of procedure
• Previous surgery, radiotherapy or I131 therapy on neck
• Video-assisted or endoscopic thyroidectomy
• Severe comorbidities
• Coagulation disorders