To begin the procedure, pneumoperitoneum is created in the abdominal cavity. Our team uses a Veress needle in the left upper quadrant. Once the abdominal pressure reaches 15 mm Hg, trocars are placed in the abdomen. A 12 mm trocar is placed supraumbilically, and 5 mm trocars are placed in the right flank, the right lower quadrant, and the left lower quadrant.
The camera is introduced and the abdominal cavity is assessed. The surgeon must look for peritoneal implants,and assess the length of the sigmoid colon and the need to mobilize the splenic flexure, as well as any other findings.
The patient is placed in the litothomy position, in Trendelenburg, and tilted to the right. Two teams are working simultaneously at this time. The transanal team includes the main surgeon sitting between the patient’s legs, the assistant to the left and the scrubbed nurse to the right. The abdominal surgeon is to the patient’s right, the first assistant to his left, the scrubbed nurse to the right and a second assistant at the patient’s left side.
The transanal platform is then placed. First, the Lone Star retractor is used to locate the dentate line. We use anal dilators to facilitate placement of the gel point platform. The platform is folded in a U-shaped manner to facilitate its introduction in the lubricated anal canal. The device is adjusted with the introducer over the levators and 2 stitches at 3 and 9 o’clock are placed to fix it. Trocars are placed in the gel path cap at 2, 6 and 11 o’clock. If a continuous insufflation system is used, the trocar is usually placed at 2 o’clock. The cap is then placed on the transanal platform and the lid is closed.
The pursestring suture is used to close the rectal cavity below the tumor, ensuring an oncologic margin: 5 cm for high rectal cancer, 2 cm for mid-rectal cancer and in the free macroscopic margin in low tumors.
A 0 PDS or prolene suture on a 26 mm needle is used, starting at 12 o’clock and continuing clockwise with a 1-2 mm space between stitches. In women, the anterior stitches must be carefully placed to avoid grasping the vaginal wall. While performing this step, the abdominal team clamps the colon at the level of the rectosigmoid junction to prevent colonic distension.
TaTME allows for clear identification of the distal edge of the tumor; then, at the desired distance, the pursestring suture is placed in order to achieve a clear distal resection margin.
Once completed, it should be tied down either intraluminally with a knot-pusher or outside after removing the platform cap.
Once the pursestring is tied down, the cap is placed back on the platform and the pneumorectum is established. With the help of the electrocautery, the rectal mucosa is marked circumferentially, about 1 cm from the pursestring knot, where the mucosal folds end. Small tattoos are then made that will be connected once the marks are completed. The mucosal dissection will progress from partial to full thickness, transecting the rectal wall to continue along the mesorectum.
Dissection should progress circumferentially, avoiding creating a funnel. Posteriorly, the dissection will continue to the presacral fascia level. If the dissection continues too posterior, the presacral vessels can be injured with the subsequent bleeding. At the lateral side, the parietal fascia should be our landmark, for if we go too lateral into the lateral wall, nerves and vessels can be injured. Anteriorly, the rectovaginal wall has to be carefully dissected. Placing a vaginal retractor or by digital exam, the border with the vagina is localized and gently dissected. In males, the prostate should be left anteriorly, to avoid any prostatic bleeding, or an even worse complication such as urethral injury. The abdominal team should be working simultaneously on the dissection of the inferior mesenteric vessels and the dissection of the upper part of the rectum. The two teams’ rendezvous is usually anterior at the level of the Douglas pouch. Once both teams connect, the dissection will be completed circumferentially. At this point, the specimen can be extracted transabdominally or transanally.
If needed, the splenic flexure can be mobilized. The inferior mesenteric vein is located at the Treitz angle and dissected. The pancreas is visualized and the dissection continues into the lesser sac, toward the splenic flexure to completely mobilize the flexure.
Then it is time for the anastomosis. The proximal colon should reach the pelvis with no tension and no torsions. The proximal colon is prepared; all extraneous fat and tissue is removed and the vascular supply is assessed. After vascular assessment, the proximal colon is prepared with the pursestring device. The EEA detachable anvil is introduced into the proximal colon and secured with the pursestring suture.
A distal pursestring is made in the rectal stump through the transanal port. Then the EEA stapler is gently introduced into the anal canal and the remaining rectum. The EEA spike is guided through the distal pursestring with a plastic tube, and pulled transabdominally until the spike has gone completely through the pursestring. The distal pursestring is tied down.
The anvil is then attached to the spike under abdominal monitoring. Once the anvil and the head are attached to each other, two circular rows of staggered staples are applied and a circular blade cuts out the interior tissue, communicating both lumens. The technique is the same for end-to-end and side-to-side anastomosis, with only the way in which the head is positioned in the graft changing.
Injecting Indocyanine Green allows us to perform a real-time intraoperative assessment of the colonic perfusion, helping in the decision on where to locate the proximal colonic transection point.
Finally, a loop ileostomy is created if indicated and the abdominal wall ports are closed.