On the suitability of Thiel cadavers for natural orifice transluminal endoscopic surgery (NOTES): surgical training, feasibility studies, and anatomical education

Background: Surgical training in virtual, animal and cadaver models is essential for minimally invasive surgery. Thiel cadavers are suitable for laparoscopy, but there are few data about the use of embalmed (Tutsch method) and slightly embalmed (Thiel method) cadavers in procedures of Natural Orifice Transluminal Endoscopic Surgery (NOTES), which are usually developed and learned on swine models and fresh frozen cadavers. The aim of this study was thus to assess the use of these cadavers for NOTES approaches.Methods: The following surgical procedures were evaluated: transanal total mesorectal excision (four cadavers: one Tutsch, two Thiel, one fresh frozen), transanal ileorectal bypass (five cadavers: one Tutsch, three Thiel, one fresh frozen), and transvaginal appendectomy (two Tutsch cadaver).Results: The Thiel method ensured tissue flexibility and consistency suitable for performing the above surgical procedures with good results and without complications, with only a small increase in rigidity with respect to fresh specimens. Cadavers embalmed with higher formalin concentrations (Tutsch method) were more difficult to use, due to high tissue rigidity and resistance of the abdominal wall to pneumoperitoneum, although NOTES accesses were possible.Conclusions: Thiel cadavers are suitable for transanal/transrectal and transvaginal NOTES approaches, for training surgical residents/specialists and also for surgical research. In minimally invasive surgery (and particularly in NOTES), integration between cadaver (fresh frozen and/or Thiel) and animal models would represent the gold standard, allowing guaranteed knowledge of and respect for human surgical anatomy and correct management of surgery on living subjects. NOTES approaches to human cadavers may also be proposed for the anatomical education of medical students