Page 291 - Read Online

Page 4 of 12 De Rosa et al. Mini-invasive Surg 2020;4:34 I http://dx.doi.org/10.20517/2574-1225.2019.53

Transanal phase: the transanal phase commences with a digital rectal examination to ensure the rectum
is empty and that the clinical findings correlate with the MRI scan. The placement of a self-fixing anal
retractor (Lone Star CooperSurgical, Trumbull, CT, USA) may be useful to better expose the anal canal,
particularly in male patients with a long anal canal. Insertion of the transanal platform should reveal distal
rectal mucosa through the anal channel. Fixation of the TAMIS port to the anal margin, positioning of the
ports in the gel-cap with attachment, and gentle insufflation will facilitate clear views and safe operating.
Initial laparoscopic inspection will allow assessment of the height of the tumor from anal verge in order to
plan the positioning of the purse-string and the rectotomy.

A purse-string suture is placed at least 10 mm distal to the tumor to seal the rectal lumen, and then rectal
irrigation eliminates debris and prevents the possible implantation of free cancer cells.

Carbon dioxide is insufflated into the distal rectal lumen to obtain a stable pneumorectum with a pressure
of 10-20 mmHg and the rectal mucosa is marked circumferentially with monopolar hook. A full thickness
rectotomy is started, usually posteriorly where the plane between presacral fascia and mesorectum is more
easily identified, but slightly laterally where the ano-coccygeal ligament is less easily encountered.

The rectal transection is performed by opening the different layers of the rectal wall until the mesorectal
plane is identified. Once the whole circumference of the distal rectal wall has been divided, the rectal
specimen will retract upwards slightly, revealing the posterior mesorectal fascia. At this stage, the closed
TM
purse-string can be reinforced with a second V-Loc suture (Covidien, Mansfield, Ma) to reduce the risk
of intraluminal leakage during the pelvic dissection. The posterior plane is developed first, anterior to the
pre-sacral fascia and along the angel hair of the mesorectal fascia which is kept intact. The anterior plane
is approached afterward, keeping the dissection in front or behind Denonvillier’s fascia according to the
rectal cancer position. The lateral dissection can then proceed, using the areas of correct dissection from
the front and back to guide the dissection; this will minimize the risk of injuries to the neurovascular
structures laterally and antero-laterally. Mesorectal dissection should proceed in a cylindrical fashion
avoiding distortion of the specimen. Entry into the abdominal compartment should be delayed as late as
possible, as accurate mesorectal dissection is impaired once a communication is established between the
two cavities. When the dissection is complete, a careful assessment is made of whether the specimen can
be safely extracted transanally or not, considering the size of both the specimen but also the stage of the
cancer. The length of the remaining distal rectal cuff will determine whether a hand-sewn anastomosis will
be required or whether there is adequate tissue for a distal purse-string to be inserted in preparation for a
stapled anastomosis. Distal purse-strings can be inserted laparoscopically or as an open procedure with the
TAMIS port still in-situ but drawn distally to stent the anorectal lumen or with the TAMIS port removed
and the Lone Star retractor giving access. Various methods of stapled anastomosis techniques have been
[25]
described .

[26]
Techniques to assess the vascular supply to the anastomosis have been described , but one of the benefits
of TaTME is direct inspection and palpation of the whole circumference of the anastomosis prior to the end
of the operation. This may allow selective defunctioning stomas to be performed according to individual
patient risk factors.

INDICATIONS
Ideal candidates for TaTME are patients with mid or low rectal cancer (within 10 cm from the anal verge),
especially in male patients (because of the narrow pelvis or prostate hypertrophy/previous prostate surgery),
obesity, bulky tumors, or after neoadjuvant radiotherapy, and, for these reasons, this approach may have
the most to offer these patients. The San Gallen Consensus concurs that TaTME may be technically easier
[27]
compared to abdominal techniques in this group of patients .