Surgery via natural orifices in human beings: yesterday, today, tomorrow.

BACKGROUND: We performed an evaluation of models, techniques, and applicability to the clinical setting of natural orifice surgery (mainly natural orifice transluminal endoscopic surgery [NOTES]) primarily in general surgery procedures. NOTES has attracted much attention recently for its potential to establish a completely alternative approach to the traditional surgical procedures performed entirely through a natural orifice. Beyond the potentially scar-free surgery and abolishment of dermal incision-related complications, the safety and efficacy of this new surgical technology must be evaluated.
METHODS: Studies were identified by searching MEDLINE, EMBASE, Cochrane Library, and Entrez PubMed from 2007 to February 2011. Most of the references were identified from 2009 to 2010. There were limitations as far as the population that was evaluated (only human beings, no cadavers or animals) was concerned, but there were no limitations concerning the level of evidence of the studies that were evaluated.
RESULTS: The studies that were deemed applicable for our review were published mainly from 2007 to 2010 (see Methods section). All the evaluated studies were conducted only in human beings. We studied the most common referred in the literature orifices such as vaginal, oral, gastric, esophageal, anal, or urethral. The optimal access route and method could not be established because of the different nature of each procedure. We mainly studied procedures in the field of general surgery such as cholecystectomy, intestinal cancers, renal cancers, appendectomy, mediastinoscopy, and peritoneoscopy. All procedures were feasible and most of them had an uneventful postoperative course. A number of technical problems were encountered, especially as far as pure NOTES procedures are concerned, which makes the need of developing new endoscopic instruments, to facilitate each approach, undeniable.
CONCLUSIONS: NOTES is still in the early stages of development and more robust technologies will be needed to achieve reliable closure and overcome technical challenges. Well-designed studies in human beings need to be conducted to determine the safety and efficacy of NOTES in a clinical setting. Among these NOTES approaches, the transvaginal route seems less complicated because it virtually eliminates concerns for leakage and fistulas. The transvaginal approach further favors upper-abdominal surgeries because it provides better maneuverability to upper-abdominal organs (eg, liver, gallbladder, spleen, abdominal esophagus, and stomach). The stomach is considered one of the most promising targets because this large organ, once adequately mobilized, can be transected easily with a stapler. The majority of the approaches seem to be feasible even with the equipment used nowadays, but to achieve better results and wider applications to human beings, the need to develop new endoscopic instruments to facilitate each approach is necessary.