Fundamentals of Rectal Cancer Surgery
Surgical Techniques for Length
Overview
A well-vascularized segment of colon which can reach the rectum or the anus without tension is essential for a healthy anastomosis following total mesorectal excision. Achievement of this typically begins with complete mobilization of the sigmoid and descending colon, and often, the splenic flexure.[1] The sigmoid colon, descending colon, and their mesentery are mobilized to the midline such that the left gonadal vessels and the left ureter are easily visible within the retroperitoneum. Complete mobilization of the splenic flexure (as described in a previous section) can be confirmed by seeing that the mesentery of left transverse and left colon are free from the pancreas, spleen, and left kidney resulting in those organs being exposed. The transverse mesocolon can be mobilized to the middle colic vessels.[2]
In addition to complete mobilization, high ligation of the inferior mesenteric artery (IMA) and inferior mesenteric vein (IMV), with preservation of the bifurcation of the left colic artery, allows additional length for a distal colorectal or a coloanal anastomosis.[1] For most patients, high ligation of the IMV at the ligament of Treitz is the maneuver that allows for the greatest lengthening of the descending colon mesentery. In addition, adhesions between the proximal jejunum and transverse mesocolon can be incised. Commonly, the greater omentum can extend from the transverse colon to the descending colon and prevent the colon from having a straight course. Thus, taking down these adhesions will add additional length. Also, depending on how much rectal length is left behind after the specimen is transected, full mobilization of the rectum circumferentially to the pelvic floor may help to gain an additional 1–2 cm of length.[2]
Depending on previous colon surgeries, the length of viable bowel left after transection of the IMA, and the length of the middle colic vessels, there are rare cases where creating a tension-free anastomosis is still difficult to achieve. Therefore, it is important to be aware of two techniques that are helpful in this less common and very difficult scenario: 1) the retroileal procedure, and 2) the counterclockwise rotation of the cecum (also referred to as the Deloyers procedure).
When the retroileal procedure is required, the middle colic artery will require transection if not previously done. The viability of the pre-anastomotic colon then relies on the right colic or ileocolic vessels. The distal colon is passed through a window created by incising mesentery between the superior mesenteric and ileocolic vessels.[3] The retroperitoneal attachments of the terminal ileum are also incised to allow the fully mobilized right colon to pass through this mesenteric defect toward the pelvis. The anastomosis can then be constructed in the usual fashion. Figure 1 shows the finished product of this technique. The first video below (Laparoscopic retro-ileal pull-through colorectal anastomosis technique) illustrates this procedure in a step-by-step manner as a laparoscopic retroileal pull-though colorectal anastomosis. The second video below (Laparoscopic extended left colectomy with retrolileal transverse colon to rectal anastomosis) shows this technique after an extended left colon resection.[4][5]
Another option, initially described as the Deloyers procedure, is complete mobilization of the cecum, right colon, and hepatic flexure. This approach allows for the counterclockwise rotation of the colon and passage of the large bowel along the right side of the abdomen and into the pelvis[6] (Figure 2 and the video below). It is important to note that this maneuver will displace the position of the appendix, so appendectomy should be considered to avoid a misdiagnosis at a later date.[7][8]
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