The nondominant hand elevates the colon, extracting it out of the abdomen and to the patient’s right, while the assistant retracts the abdominal wall to the left. In this manner, the white (Toldt) line comes into view under tension between the parietal and descending colon peritoneums. Cutting with cautery precisely on this line exposes the underlying alveolar tissue. Gentle traction and cautery free the descending colon, which now is attached only by its mesentery.

The sigmoid root has a length of 5–10 cm; the sigmoid mesentery unfolds like a fan to 25–60 cm. The surgeon’s and assistant’s positions as well as traction are similar to those followed in descending colonic mobilization; the sigmoid is mobilized by continuing the cautery incision on Toldt’s line at the outer aspect of the sigmoid. Alveolar tissue is exposed and can be pushed with a wet sponge down to the root of the sigmoid mesentery, care being taken to avoid injury to the left spermatic vessels, and visualizing the left ureter. The ureter lies on the posterior abdominal wall, crossing anteriorly the bifurcation of the internal and external iliac vessels. The ureter contracts with a gentle touch of an atraumatic instrument; no need to mark or tape it, just identify it to make sure to avoid it.

As the sigmoid is pulled out of the abdomen, the peritoneal surface at the medial aspect of the mesosigmoid root is incised, from the aortic bifurcation caudally along the medial aspect of the right iliac vessels, and the incision is continued between the rectum and pelvic brim, rectum and bladder or uterus, as the assistant applies opposite traction to these organs. Parallel and superficial to the aortic bifurcation lie the hypogastric nerves (sexual function) (Fig. 17.2). Once identified, avoid traction on the nerves during the next step. Following the alveolar plane below the aortic bifurcation bluntly down to the pelvic cavity, the rectum/mesorectum can be dissected free from the presacral space, down to Waldayer’s fascia (Fig. 17.3). If cancer is not the problem, mobilization is accomplished within seconds by gentle insertion of the dominant hand. Neither cautery nor ligation is needed. Avoid pressing against mesorectum with the tip of fingers, because this may perforate a fragile rectum, leading to troublesome bleeding and a source of potential contamination; use the palm of the hand. To complete rectal mobilization circumferentially, using (long shaft) cautery bursts dissect all connective tissues laterally from both sides freeing the lateral mesorectum from the pelvic fascia. Usually, no vessel is encountered: no need for ligation, as simple cautery forceps suffice. Finally the anterior rectal plane is incised and freed from its attachments to the uterus/vagina in women or bladder/seminal vesicles/prostate in men. Putting tension to rectum by posterior traction and contra-tension by pulling (e.g., with a St. Marks-type retractor), the anterior tissues (vagina, bladder, etc.) against the pubic bone, the correct plane is found (Fig. 17.3); it is essential to remain in the specific plane (Denonvillier’s fascia) until reaching the deepest part of dissection, avoiding damage on nervi erigentes and its branches, responsible for sexual function (Fig. 17.2). In women, vision can sometimes be improved and working space increased by temporarily stitching the dome of the uterus to the pubic skin, elevating it out of the operating field.

Vessel ligation differs according to the disease and what segment (right and left colectomy, sigmoidectomy, low anterior resection, or segmental resection) is performed. The regional lymph nodes reside along the feeding vessels and can be removed as needed. In a non-oncologic emergency, just the diseased part of the colon along with a sphenoid part of its mesentery is all that has to be excised. The appex of this sphenoid part goes down to the mesenteric root, so there are fewer vessels to ligate, saving time. Energy-driven devices (which seal and cut vessels) are effective especially in areas with diminished working space (i.e., pelvis) and save time.

Prerequisites include:

Technical issues regarding anastomoses: