ABSTRACT
Conventional transanal excision predated any other form of rectal cancer surgery. It was first described in 1739 and further developed in the 19th century. The restricted view and limited range hindered further development and were believed to contribute to the high rates of local recurrence. Aside from colonoscopic techniques described elsewhere, TEM was the first operative endoscopic procedure designed for procedures in the gastrointestinal tract. The drivers for the development of this approach were the inaccessibility of the upper rectum, invasiveness of the posterior approaches and the limited view provided by the conventional transanal approach. Transanal endoscopic operation (TEO) is a variant of TEM using Storz instrumentation with a conventional laparoscopic insufflator and a standard laparoscope optic. This makes it simpler, cheaper and more readily available but has the disadvantage of a less stable platform. The lack of binocular vision and, hence, tridimensional visualisation is a perceived weakness of TEO compared to TEM.
