Thyroidectomy using pure natural orifice transluminal endoscopic surgery in a porcine model.

Surgical procedures for thyroid disease that provide cosmetically acceptable results are in demand. Natural orifice transluminal endoscopic surgery (NOTES) is performed through natural orifices and thus avoids incision of the body wall. This study aimed to develop an incision-free surgical procedure for thyroid lobectomy using pure NOTES with an oral approach. In six pig carcasses, an incision was made between the mandible and subcutaneous tissue under direct vision. After subcutaneous dissection and identification of the hyoid bone, the operative field was developed under endoscopic view. After the thyrohyoid membrane was identified, dissection was continued along the thyroid cartilage until the cricoid cartilage was identified and the thyroid isthmus was reached. An original retractor was inserted between dissected tissues to lift and fix the carcass. The thyroid gland was successfully removed through the incision. Similar macroscopic and histological findings were observed on the normal and treated sides, with no damage to the recurrent laryngeal nerves. The times required for securing the operative field and thyroidectomy improved with each operation. This study suggests the feasibility and safety of using pure NOTES for thyroidectomy through a subcutaneous route with an original retractor.