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Page 2 of 9 Yap et al. Mini-invasive Surg 2019;3:3 I http://dx.doi.org/10.20517/2574-1225.2018.57

Transanal total mesorectal excision (TaTME) is the latest innovation that aims to overcome these significant
[3]
limitations in rectal cancer surgery. It has its roots in 1984, when Buess et al. described transanal
endoscopic microsurgery (TEMs) using a fixed rectoscope platform that improved both visibility and
extended the extent of the surgical field. Although expensive, this technique resulted in more negative
margins and less fragmentation of the specimen when compared to conventional transanal excision. Further
development of minimally invasive and advanced endoscopic platforms such as transanal minimally invasive
[4]
surgery (TAMIS) and the ability to create and maintain pneumorectum led finally to the development of
[5]
the TaTME for en-bloc resection of rectal cancers as first described by Sylla et al. in 2009. Indeed, it is the
development of CO insufflation for the rectum using the AirSeal device (CONMED Corp., Utica, NY) with
2
sufficient smoke evaluation that brings the most significant progression from TEMs/TAMIS to TaTME.
The implementation of novel technical and technologic innovations in surgery has often been fraught with
unintended consequences. With an emphasis on safety and acceptability of clinical outcomes, the lessons
learned from missteps arising throughout the implementation of minimally invasive surgery in other fields
(e.g., laparoscopic cholecystectomy and bile duct injury) have justifiably led the surgical community to heed
the cautionary tales of early adopters. The technical complexity of TaTME, in addition to the identification of
new or rarely-seen anatomic landmarks and planes have led to the occurrence of otherwise rare complications
such as urethral injury. This has led to reflection and delay in the dissemination in the technique.

This paper aims to provide a summary of the indications, considerations, surgical technique and evidence
for TaTME. It will assume a certain amount of prior knowledge in the treatment of rectal cancer, where
areas such as pre-operative staging and standard treatment modalities will be only briefly mentioned.

PREOPERATIVE EVALUATION
A thorough evaluation of the recently diagnosed rectal cancer patient is of the utmost importance to
determine an appropriate treatment plan. This evaluation includes a complete history and physical
examination, including digital rectal exam and rigid proctoscopy. Preoperative work-up should include a
full colonoscopy to rule out any synchronous lesions. A baseline carcinoembryonic antigen level should
be obtained prior to treatment as a prognostic tool and for post-treatment surveillance. A variety and
combination of radiographic studies can be performed preoperatively with a different associated benefit profile
for each study. Computed tomography (CT), magnetic resonance imaging (MRI), endoanal ultrasound (EUS),
positron emission tomography (PET) and PET-CT may be used depending on the clinical situation.

Of these, pelvic MRI is of most interest when considering cases for TaTME. These should be done with the
[6-8]
use of a pelvic-specific coil and thin-sectioned, multiplanar T2-weighted images . MRI is the best current
modality for determining the extent of locally advanced tumors, identifying the mesorectal fascia/the
circumferential resection margin (CRM), and is at least equal to EUS for the staging of mesorectal lymph
nodes [9-11] . However, the breath of anatomical information provided by MRI also allows for preoperative
planning in TaTME cases. Careful study of the pre-operative MRI can help the surgeon consider how to
proceed at difficult points in the operation. Attention should be taken to path of the mesorectal fascia which
is clearly delineated on MRI. As orientation can be challenging intra-operatively, identifying the angle by
which the mesorectum first dives posteriorly and then curves anteriorly may help the surgeon stay within
the correct plane. Further attention should be drawn to where the CRM may be threatened by tumor during
the operation.

TaTME was developed to aid in the challenging mid to low rectal cancer cases, although precise definition
of its indications has not been fully evaluated. A recent consensus statement was published which listed the
following indications for TaTME: (1) male gender; (2) narrow and/or deep pelvis; (3) visceral obesity and/
2
or a body mass index (BMI) > 30 kg/m ; (4) prostatic hypertrophy; (5) a tumor height < 12 cm from the anal