The splenic flexure and left colon is mobilized laparoscopically. The patient cart is then docked either at an angle on the patient’s left side or between the legs for pelvic dissection.

Two separate dockings include the initial docking for mobilization of splenic flexure and the second docking for sigmoid and pelvic dissection. An alternate technique recently described is to undock the patient cart, but rather than move the patient cart, the patient bed is moved instead into the new position.

The patient cart is obliquely placed on the patient’s left. The central column of the patient cart should line up along an imaginary line between the camera port and the left anterior superior iliac spine.

Moving the robotic arms into different ports allows both dissection of the left colon/splenic flexure and pelvic dissection. Docking on the patient’s left also allows access to the patient’s perineum, enabling the surgeon to check his/her dissection by digital examination without undocking the patient cart.

This is the standard practice of this department.

The sigmoid colon mesentery is lifted up using arm 2 to reveal the base of the mesentery and IMA (Fig. 17.5). The assistant uses a non-toothed grasper to retract the small bowel away from operative field. Mesentery above sacral promontory is incised and dissected using arms 1 and 3. The IMA is identified and skeletonized. The aorta is used as a landmark for dissection of the IMA. Keep the aorta horizontal while visualizing the IMA. A D3 dissection is performed by dissecting a cuff of the mesentery at least 1 cm around the origin of the IMA and included in the specimen, while the periaortic sympathetic nerve plexus is preserved (Fig. 17.6). Once skeletonized, the IMA is ligated at its origin with Hem-o-lok clips. This can be performed either by the assistant or via the robotic arm. Using the robotic arm does require exchanging the instrument arm but does have the advantage of better rotation and angulations provided by the robotic wrist. It is best if the IMA is not ligated flush against the aorta. A short cuff is recommended in case of bleeding.

We have also developed a technique for patients with cardiovascular diseases whereby the IMA is ligated at a low level while preserving the left colic vessels but oncological resection is not compromised by including the same mesenteric tissue in the final specimen. This is done by carefully skeletonizing the IMA, dissecting mesenteric tissue from the IMA, until the left colic artery is identified. Mesenteric tissue is dissected off the left colic pedicle to allow the IMA to be ligated above the left colic branch.

It is of importance to identify the nerves and preserve them. The 3-dimensional view is very helpful in identifying the nerves. By skeletonizing the IMA, the nerves are better identified and preserved. The assistant may assist with retraction with a sucker or grasper.

The IMA is then lifted toward the anterior abdominal wall and the descending colon and sigmoid mesentery is dissected from the retroperitoneum. Dissection is performed by using a sharp dissection. The plane between the mesentery and the Gerota’s fascia can be identified using both traction and countertraction of both arms 2 and 3. Sometimes the plane can be better identified by gentle pushing using the instrument arms. It is important to constantly reposition arm 2 to help with retraction. Arm 2 should be retracting the mesentery upward toward anterior the abdominal wall. This allows arm 3 to be used for countertraction. Any bleeding can be controlled using bipolar in the left robotic arm (arm 3) or the monopolar scissors in the right arm (arm 1).

Dissection of the colonic mesentery off the retroperitoneum is continued proximally toward the splenic flexure. The IMV is identified on the lateral side of the duodenum and dissected.

Before ligation of the IMV, the arc of Riolan (otherwise known as the meandering artery) should be sorted. The arc of Riolan, when present, may be significant in affecting the blood supply provided by the marginal artery. If required, the IMV should be ligated to ensure the arc of Riolan remains intact (Fig. 17.7). Ligation of the IMV does not affect oncological outcome but provides mobilization of the left colon to reach the pelvis during anastomosis.

The boundaries of medial dissection are the inferior border of the pancreas proximally and the aorta medially. Laterally, dissection is carried out as far laterally as possible until the visualization of the psoas muscle. The left ureter should be visualized crossing the left iliac vessels and preserved.

If the splenic flexure is mobilized, proximal dissection is extended above the pancreas and lesser sac entered inferiorly during medial dissection. This is done by incising the peritoneum overlying the transverse colon mesentery at the level of the pancreas. Dissection of the mesentery off the superior aspect of the pancreas will lead you into the lesser sac. Once lesser sac is entered, the transverse colon mesentery can be dissected off its attachment to the anterior aspect of the pancreas (Fig. 17.8). The assistant places the grasper into the lesser sac and lifts the transverse colon mesentery upward. This dissection is carried laterally toward the splenic flexure. This is identified by the omentum that attaches to the tail of the pancreas.

Once medial dissection is complete, lateral dissection can be performed. The sigmoid colon is separated from its peritoneal attachments commencing at the sigmoid notch by dissecting along the line of Toldt. The colon is retracted medially and inferiorly (i.e., toward the RLQ) by the assistant and left for the surgeon’s left robotic arm to be used for countertraction (Fig. 17.9). If the medial dissection is adequate, lateral dissection should quickly join the dissection as previously done medially.