The experimental development of the eMIT technique has led to its first clinical application in humans. In this prospective proof-of-concept study in humans, the thyroid gland was reached via the transoral endoscopic approach in an anatomically defined layer without any relevant damage to vessels. Limitations to this technique are determined by specimen volume (up to 30 ml) and nodule size (up to 20 mm).

With the development of an exclusively endoscopic approach for thyroid resection (eMIT) and its first clinical application, we could show the safety and feasibility of another natural orifice surgery procedure. One major concern before surgery was possible infection of the cervical spaces by introduction of oral flora to these regions. Investigating this infection risk, Hong and Yang evaluated the surgical results associated with the intraoral approach for submandibulectomy in a series of 77 cases of chronic sialadenitis and benign mixed tumors. The infection rate was 2.6% (2 patients) compared with 7.3% in a control group of 251 patients who underwent a transcervical procedure. Therefore, we estimated the infection risk to be lower than with conventional transcervical approaches. The clear advantages of this technique are its minimally invasive character, its reduction of surgical trauma, its direct access to surgical planes and spaces, its avoidance of swallowing disorders and postoperative dysphagia, and finally, its avoidance of any skin scars. Further trials are already being conducted.

BACKGROUND: The transoral endoscopic approach for thyroid surgery was based on a previous attempt to reach the thyroid gland by an axilloscope. In contrast to this single-port access, endoscopic minimally invasive thyroidectomy (eMIT) uses three access points (sublingual and bivestibular). This results in a sufficient triangulation of instruments, making surgical procedures in the anterior neck region possible. METHODS: The idea and development of the eMIT technique are described in detail. Anatomic studies, the development of the surgical access in a cadaver study, and the animal study for safety and feasibility of this transoral endoscopic approach for surgery of the anterior neck are outlined. Also, the foundations and ethical aspects are addressed in the context of developing a surgical innovation, which resulted in the first clinical application of this technique in humans. RESULTS: The preclinical studies regarding endoscopic minimally invasive thyroidectomy proofed feasibility in a human cadaver studies as well as safety in a short-time survival animal study. The first clinical application in a 53-year old patient was successful without any significant complications; expected benefits (no postoperative pain or dysphagia, no visible scar) could be demonstrated. CONCLUSIONS: The eMIT technique represents a promising new surgical approach for endoscopic surgery in the anterior neck region. The whole development was based on principles for surgical innovation published after the authors' preclinical studies. At this writing, after an initial clinical study with humans, the time has come to compare this new technique with other endoscopic and minimally invasive approaches in a prospective randomized multicenter trial.

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