title: Transoral endoscopic thyroidectomy with central neck dissection: experimental studies on human cadavers.
abstract: BACKGROUND
  With the development of natural orifice trans-luminal endoscopic surgery, studies on transoral video-assisted thyroidectomy in preclinical experiments (e.g., human anatomy and animal trials) were progressing gradually. From 2009 to 2011, embalmed human cadavers were dissected to define the anatomical location, surgical planes, and related neural and vascular structures to create a safe transoral access to the front cervical spaces. Recently, experimental transoral endoscopic thyroidectomy was performed to verify the feasibility of this approach on 15 fresh specimens.
  
  
  METHODS
  Fifteen specimens were placed in the supine position with slight neck extension. Endoscopic incision was made on the midline between the Wharton's duct papillae and two other incisions were made on mandibular first premolar buccal mucosa. Sublingual combined bilateral vestibular tunnels were created from oral cavity to the cervical region. The neck subplatysmal working space was insufflated with CO2 at 6-8 mmHg. The bilateral thyroid lobes and central lymph nodes were dissected under craniocaudal view.
  
  
  RESULTS
  Three incisions were made in the oral cavity without any incisions on the body surfaces. The distance from the oral cavity to front neck region was the shortest. Bilateral thyroid lobes and central neck region were fully resected via transoral approach. This approach provided a craniocaudal view, in which retrosternal thyroid gland and lymph nodes were easily accessible. The recurrent laryngeal nerve could be identified safely on the inferior cornu of the thyroid cartilage. The only structure at risk was the mental nerve. Camera motion was somewhat limited by the maxillary dentition. The volume of harvested thyroid nodule through sublingual tunnel in the fifteen human cadavers was (40 ± 15) cm(3).
  
  
  CONCLUSIONS
  The transoral procedure is progressive and innovative which not only gives the best cosmetic result and minimal access trauma but also provides a craniocaudal view.
authors.affiliation: Department of Orthopedics, Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510655, China.
authors.forename: Peiyi
authors.initials: P
authors.lastname: Guo
authors.affiliation: Department of General Surgery, Zhongshan Boai Hospital of Southern Medical University, Zhongshan, Guangdong 528400, China.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Department of Anatomy, Southern Medical University, Guangzhou, Guangdong 510515, China.
authors.forename: Zihai
authors.initials: Z
authors.lastname: Ding
authors.affiliation: Department of Anatomy, Zhongshan School of Medicine, Sun Yatsen University, Guangzhou, Guangdong 510080, China.
authors.forename: Guoliang
authors.initials: G
authors.lastname: Chu
authors.affiliation: Department of Anatomy, Zhongshan School of Medicine, Sun Yatsen University, Guangzhou, Guangdong 510080, China.
authors.forename: Huosheng
authors.initials: H
authors.lastname: Yao
authors.affiliation: Department of Orthopedics, Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong 510655, China. Email: pantao@126.com.
authors.forename: Tao
authors.initials: T
authors.lastname: Pan
authors.affiliation: Department of Anatomy, Zhongshan School of Medicine, Sun Yatsen University, Guangzhou, Guangdong 510080, China. Email: wanghq@mail.sysu.edu.cn.
authors.forename: Huaqiao
authors.initials: H
authors.lastname: Wang
mesh_terms: D002102:Cadaver; D004724:Endoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D037981:Neck Dissection / Q000379:methods*; D013965:Thyroidectomy; D020535:Video-Assisted Surgery / Q000379:methods*