Total mesorectal excision remains the gold standard for surgical treatment for rectal cancer to achieve excellent oncological outcomes. The transanal approach to the mesorectum was introduced to complement conventional surgery so that technical difficulties related to the distal rectal dissection could be overcome. Since its introduction, interest in transanal mesorectal excision has been growing and it appears that the benefits are maximal in patients with mid-low rectal cancer where anatomical and pathological factors present the greatest challenges. Current evidence demonstrates this approach is safe and feasible, with an acceptable morbidity profile, but with specific complications related to the technique. Oncological and functional data seem comparable to the conventional approaches, but most of the results come from small studies with short-term endpoints. Robotics, when available, might potentially overcome the difficulty of distal rectal dissection with a shorter learning curve compared to the transanal approach, but with higher costs. The aim of this review is to critically evaluate the available literature concerning transanal total mesorectal excision so that we can better define its role in the management of rectal cancer.

Transanal surgery has evolved significantly in the past few decades. With the technological advancements of endoscopic systems, minimally invasive approaches in transanal surgeries are quickly increasing in popularity. Transanal endoscopic microsurgery was developed initially with subsequent transanal minimally invasive surgery (TAMIS) being introduced as an alternative in 2009. Over the past decade, more and more papers have been published on TAMIS, regarding the management of benign/malignant rectal lesions as well as repair of anastomotic leaks, anastomotic strictures, rectovaginal/rectourethral fistula, etc. This review details the progress of transanal surgery and the use of TAMIS in different scenarios.

Transanal minimally invasive surgery (TAMIS) is a surgical technique which allows the local excision of rectal benign tumors and early stage cancers measuring up to 4 cm and lying within 6-8 cm from the anal verge. It is performed by means of a disposable transanal platform and conventional laparoscopic instruments, proving to be effective and easily available. Hence, TAMIS soon became a valid alternative to other transanal resective procedures, especially transanal endoscopic microsurgery, and rapidly spread. Moreover, soon after its introduction, TAMIS started to be performed also using robotic technologies, but no clear advantages were found to date. This review is intended to provide a general overview on TAMIS, with a special focus on its association with robotic systems and the perspectives of this approach.

Total mesorectal excision (TME) is accepted as the standard technique in rectal surgery. In recent years, significant attention has been focused on transanal TME (taTME) as a promising approach for rectal cancer. However, this approach can involve an inherent risk of male urethral injury, because there is no clear anatomical border between the rectal muscularis propria and rectourethral muscle. We used a lighted urethral stent to identify the urethra during taTME for 6 patients with distal rectal cancer. In five of six cases, an infrared-detecting camera could detect a red fluorescent signal from the lighted urethral stent during the anterior dissection of the rectum, which helped us to determine the correct dissection line. A lighted urethral stent is a useful tool that helps visualize the urethra during taTME and improves taTME applicability in clinical practice.

Aim: Rates of clinically relevant postoperative morbidity after transanal endoscopic microsurgery (TEM) are low. For this reason, there are few descriptions in the literature on the management of these complications. Because of this lack of information, their importance may be either underestimated or overestimated (in the latter case, leading to overtreatment). The present article reports the frequency of the occurrence of postoperative surgical complications after TEM and describes various approaches to their management.

Methods: An observational study was carried out with prospective data collection and retrospective analysis from June 2004 to June 2019, including all patients undergoing TEM for rectal tumors. All postoperative complications were recorded using the Clavien-Dindo classification (Cl-D), as well as preoperative, surgical, postoperative, and pathological variables.

Results: During the study period, 778 patients underwent TEM, of whom 716 met the inclusion criteria. Postoperative morbidity was 22.1% (158/716). Clinically relevant morbidity (Cl-D > II) was 5% (36/716). The most frequent complication was rectal bleeding, occurring in 115/716 (16.1%) patients; 85 of these 115 (73.9%) patients were grade I Cl-D. Urinary complications were rare (30/716, 4.2%). Similarly, infectious complications of perianal and pelvic abscesses appeared in 7/716 (1%) patients, two of whom required colostomy.

Conclusion: Clinically relevant complications after TEM are rare. For this reason, experience of these complications is limited. Here, we propose a management protocol to ensure that these complications are neither underestimated nor subjected to excessively aggressive or unnecessary treatment.

Transanal total mesorectal excision (TaTME) is widely performed for the resection of rectal cancer around the world. However, due to lower body mass index and a lack of necessity, TaTMEs have not been accepted in East Asia as generally as in Western countries. In East Asia, conventional laparoscopic surgeries have been performed with lower rates of open conversions and robotic surgery has been considered as an acceptable option for patients with narrow pelvis. This review article discusses TaTMEs from an East Asian perspective.