Place the patient in a modified lithotomy position with the hips and knees gently flexed at a maximum 15-degree angle. Greater elevation of the thighs may not allow the surgeon to move the instruments freely. The buttocks should extend slightly over the end of the operating table. This position gives proper access to the anus for endoscopy and insertion of a circular stapling device and also allows access to the perineal region in case of abdominoperineal resection. Place the right arm of the patient alongside the trunk (rather than out on an armboard) to allow room for the surgeon and second assistant, who stand on the right side of the patient. Place an orogastric tube and a urinary catheter to minimize the risk for gastric or bladder injury, respectively, during trocar insertion. Prepare and drape the abdomen and perineal region for an open procedure for the eventuality that the laparoscopic procedure cannot be safely completed. The surgeon stands on the right side of the patient, the first assistant surgeon on the left, and the second assistant, who controls the camera, to the left of the surgeon.

A CO₂ pneumoperitoneum of 12 to 15 mm Hg is established in the usual fashion, through a small vertical infraumbilical incision. A 0- or 30-degree laparoscope is then introduced, and the abdomen is thoroughly explored to assess other pathology and to determine any metastatic dissemination. To inspect the liver, the patient is brought into a steep reverse Trendelenburg position; if the technology is available, a laparoscopic ultrasound of the liver should be performed.

If the proposed operation is deemed feasible, the other ports will be positioned. The operation is facilitated by the camera and the instruments being interchangeable to all ports. For this reason, only 10- to 12-mm trocars are used; three operating port sites are usually sufficient. Place the additional trocars under direct endoscopic visualization in the right lower quadrant and at the level of the umbilicus, both along the right midclavicular line. Another port is inserted in either the left midclavicular line, also at the level of the umbilicus, or in the right upper quadrant in the midclavicular line. The port positioning takes into account the patient’s anatomy, the location of the incision for specimen retrieval, and the site of any planned stoma.

The following additional instruments are required:

Place the patient in a steep Trendelenburg position with the table tilted to the right side so that the small bowel gravitates toward the right upper quadrant of the abdomen and no retraction to the small bowel is required. Gently grasp the sigmoid colon with a Babcock clamp through the right paraumbilical port and move the bowel to the patient’s right side. This maneuver places traction on the posterior peritoneum overlying the iliac vessels. Incise the peritoneum with the ultrasonic scalpel placed through the right lower quadrant port. Sequentially slide the ultrasonic scalpel under the peritoneum, and advance it down the pelvic sidewall toward the anterior peritoneal reflection, using it to push the mesorectum and mesosigmoid medially away from retroperitoneal structures. Identify the ureter as it crosses the iliac vessels and trace it proximally as far as possible. Continue this separation of the sigmoid colon from the lateral wall cephalad along the descending colon until the splenic flexure is reached.

The abdominal and pelvic part of the ureter lies in extraperitoneal areolar tissue. The abdominal part, which descends on the medial part of the psoas major muscle, enters the lesser pelvis anterior to either the end of the common or the beginning of the external iliac vessels. The left ureter lies beneath the root of the sigmoid mesocolon. The right ureter lies behind the lower part of the mesentery and the terminal ileum. In the pelvis, the ureter is anterior to the internal iliac artery and covered by the parietal endopelvic fascia. Laterally, it lies on the fascia of the musculus obturator internus. In males, the ureters pass between the internal iliac vessels and the ascending vas deferens. Then they turn anteriorly, pass along the levator ani, and penetrate the base of the bladder in front of the seminal vesicles. In females, the pelvic part at first has the same relations as in males, but anterior to the ureters lay the ovaries. At the pelvic floor, the ureter turns anteriorly on the levator ani, turns forward slightly above the lateral vaginal fornix, and then inclines medially to reach the bladder.

Place the patient in a steep reverse Trendelenburg position. This allows the transverse colon and viscera to fall away from the spleen and stomach. While the assistant retracts the splenic flexure toward the umbilicus with the Babcock clamp, separate the mesentery of the descending colon from Gerota’s fascia until the splenic flexure is reached.

Next, approach the splenic flexure along the transverse colon. Displace the greater omentum toward the stomach and retract the transverse colon caudad to expose the avascular plane between the omentum and the transverse colon. Incise this avascular plane with the ultrasonic scalpel to enter the lesser sac and continue the dissection until the splenocolic ligament is completely divided. The sigmoid colon, the descending colon, and the transverse colon have now been fully mobilized to the midline.