Natural Orifice Surgery (NOS)-the next step in the evolution of minimally invasive surgery.

Endoscopy, which was introduced in the 20(th) century, changed the outcome of surgery by reducing the need for analgesia and shortening hospital stay. Any new surgical method should improve safety and outcome. At the beginning of the 21(st) century, the use of natural orifice surgery is a promising progress. The transgastric and transdouglas approaches are currently being investigated and evaluated. The transgastric approach still has a long way to go due to objective problems such as infections, stomach acidity, and the optimal way to ensure the safe closure of gastrotomy. The transdouglas approach, however, is already starting to establish itself and it seems that with the construction of designated instruments it will prevail in the 21(st) century.