To determine whether the use of anti-adhesion barrier after thyroid surgery can prevent the voice changes after surgery, using objective voice-related indicators.

• Randomized controlled study
• Including 40 patients in each arm
• Treatment: anti-adhesion barrier apply on the thyroidectomy space
• Control: No use of anti-adhesion barrier
• Primary outcome: VHI-30 (Voice handicap index)
• Secondary outcome: findings from stroboscopy, CSL (Computerize Speech Lab)
• Outcome measurement: preoperative, post-operative 3 months, post-operative 9 months.

Inclusion Criteria:

• Patients undergoing open thyroidectomy for thyroid cancer
• Patients whose tumor size is less than 4cm
• Patients who are not suspected of surrounding organ involvement (T4) or metastasis to central lymph nodes in preoperative imaging
• Patients with no history of voice-related diseases prior to surgery
• Patients with normal movement of both vocal cords in the preoperative vocal cord examination
• Patients who consented to the study and obtained consent for the study

Exclusion Criteria:

• Patients with uncontrolled high blood pressure, diabetes, chronic renal failure, coagulation disease, etc.
• History of cardiovascular disease (angina pectoris, heart failure, myocardial infarction, cerebral infarction, cerebral hemorrhage, etc.)
• Medical history of drug or substance disorder (alcohol, etc.)
• Patients with diseases related to airways, esophagus, and vocal cords (vocal palsy, vocal cord polyps, etc.)
• Patients who have already had adhesions in the foreground due to radiation therapy or surgery on the foreground in the past.
• Patients with a history of keloid or hypertrophic scars
• Patients planning to perform lateral cervical lymph node dissection
• Patients with medical thyroid disease, such as Graves' disease and thyroid inflammation in need of treatment
• Pregnant or lactating female patients
• Other patients who are in charge of clinical trials as unsuitable for participation in the study

In order to protect the privacy of patients, the original data of the study will not be disclosed.

Participants do not know about the use of anti-adhesion agents.