Evolution of Transanal Total Mesorectal Excision

Abstract

Minimally invasive techniques continue to transform the field of colorectal surgery. Because traditional surgical approaches for rectal cancer are associated with significant mortality and morbidity, developing less invasive approaches to this disease is paramount. Natural orifice transluminal endoscopic surgery (NOTES), commonly known as "no incision surgery," represents the ultimate minimally invasive approach to disease. Although transgastric and transvaginal approaches for NOTES surgery were the initially explored, a transrectal approach for colorectal disease is intuitive given that it makes use of the resected organ for transluminal access. Furthermore, the transanal approach allows for improved, precise visualization of the presacral mesorectal plane compared with an abdominal viewpoint, particularly in the narrow, male pelvis. Finally, experience with existing transanal platforms that have been used for decades for local excision of rectal disease made the development of a transanal approach to total mesorectal excision (TME) feasible. Here, we will review the evolution of minimally invasive and transanal surgical techniques that allowed for the development of transanal TME and its introduction into clinical practice.

Keywords: natural orifice transluminal endoscopic surgery; rectal cancer; transanal total mesorectal excision.

Fig. 1

Operative setup for transanal access in a swine model using transanal endoscopic operation (TEO) instrumentation.

Fig. 2

Comparison of specimen length for pure transanal approach (right) versus combined transanal and transgastric natural orifice transluminal endoscopic surgery (NOTES) approach (left) in a swine model.

Fig. 3

Operative setup for combined transanal and transgastric access in a human cadaver model.

Fig. 4

Demonstration of transanal total mesorectal excision (taTME) in a cadaver model. Top images show direct visualization and placement of the purse-string suture. Bottom images show placement of transanal endoscopic operation (TEO) platform transanally followed by circumferential dissection of the rectum and extension of the dissection into the peritoneal cavity.

Fig. 5

Demonstration of transanal total mesorectal excision (taTME) in a cadaver model (continued). Top figures demonstrate completion of the dissection with transanal removal of specimen. Bottom figures with hand-sewn anastomosis under direct visualization.

Fig. 6

Examples of intact transanal total mesorectal excision (taTME) specimens in a human cadaver model. Top specimen demonstrating total colectomy specimen completed using transanal and transgastric access.