Transanal Rectal Resection

Natural orifice transluminal endoscopic surgery (NOTES) is the integration of laparoscopic minimally invasive surgery techniques with flexible endoscopy technology. It has emerged as a promising new alternative to conventional minimal invasive surgery such as laparoscopic or robotic surgery. NOTES initially focused on a transgastric approach, but the technique remains experimental because of injuries to adjacent organs and gastrotomy closure. These limitations, however, have been overcome when transanal NOTES is used for colorectal surgery, such as transanal total mesorectal excision, often referred to as a “bottom‐up approach”. Transanal approaches in the form of transrectal or transcolonic NOTES appear to be alternatives for treating both colorectal and other abdominal diseases. Traditionally, benign rectal tumor and early rectal cancers located in the rectum were treated with transanal excision using a conventional anal retractor. Preservation of the anatomical integrity of the mesorectum for rectal cancer surgery is a major factor in long‐term survival and rate of local recurrence after total mesorectal excision (TME).1‐3 Now, TME is considered the standard of care for rectal cancer. In TME, the rectum and mesorectum are excised through sharp dissection under direct vision of the avascular white plane between the visceral and parietal pelvic fascia, separating the mesorectal fat from the pelvic structures. The introduction of TME surgery reduced local recurrence rates from 20 to 45 % to about 10 %.4‐7 The another important predictor of local recurrence is the involvement of the circumferential resection margin (CRM). A CRM of less than 2 mm is shown to be a strong predictor of local recurrence. Moreover, the challenge in doubling ‐stapling technique for the rectal anastomosis in a narrow pelvis and efforts to preserve the anal sphincter in very low tumors could lead to major morbidity, including anastomotic failure and pelvic nerve injury. NOTES transanal approach to TME have been reported in order to overcome these risks in patients with rectal cancer.10‐14 Advantages of the down‐to‐up approach include closer assessment of the possibility of preservation of the anal sphincter, better definition and preservation of the integrity of the distal mesorectum and clearer identification of the sacral nerves.