title: Transesophageal NOTES--a critical analysis of relevant problems.
abstract: The transesophageal access route has not become a principal topic in the discussion about NOTES up to now. Analyzing the problems in this new field of surgery, however, the transesophageal route shows high relevance. Here, all possibilities, limitations, and problems of NOTES become obvious. This paper contains a critical analysis of the literature published to date (nine full papers, five abstracts). Nearly all publications represent experimental studies in living pigs. In most cases a submucosal tunnel technique is performed as access route to mediastinum, pleural cavity, and heart. Interventions and operations include simple mediastinoscopies as well as epicardial operations after exposition of the heart. For access and manipulation, conventional flexible endoscopes and instruments are used. Clips, T-bars, or a combination of both achieve the closure. Some studies rely on spontaneous closure of the incision without any suturing or approximation. In such experimental settings, the following results are presented: Access is achieved in 90% of cases, the aim of the operation is met in 92%, technical success in closure is achieved in 90%, healing of incision assessed as good in two of five studies, satisfactory in three of five studies. Mortality, ranging from 6 to 25%, and complication rates were (surprisingly) high. It has to be stressed that analyzing these papers published to date, no adequate attention is paid to basic facts and problems of general and thoracic surgery (e.g. different forms, prevention, diagnosis and therapy of pneumothorax or differentiated forms of ventilation). Relevant differences in the anatomy and physiology of the esophagus and mediastinum between humans and pigs should additionally be taken into account to choose optimal experimental parameters when transferring results to human settings. Moreover, requirements regarding sterility and hygiene in a structure like the mediastinum, which is at high risk from the point of view of infection biology, have not yet been respected. These factors should be taken into account in further studies--as well as clinically relevant disease patterns in humans--to be able to realize possible advantages of this NOTES access in a clinical setting.
authors.affiliation: Department for General, Visceral, and Transplantation Surgery, Surgical Endoscopy, University Hospital Tübingen, Waldhörnlestrasse 22, Tübingen, Germany. chir.endo@uni-tuebingen.de
authors.forename: Karl E
authors.initials: KE
authors.lastname: Grund
authors.forename: Thorsten G
authors.initials: TG
authors.lastname: Lehmann
mesh_terms: D000818:Animals; D019723:Endoscopes; D004867:Equipment Design; D004947:Esophagus; D006801:Humans; D008481:Mediastinoscopy / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D057605:Natural Orifice Endoscopic Surgery / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D011183:Postoperative Complications / Q000209:etiology; D013045:Species Specificity; D013552:Swine; D013906:Thoracoscopy / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*