With a few exceptions, the approach and the operative technique for the abdominal part of this procedure are identical to that used for total mesorectal excision (TME) and AR. The abdominal cavity is first explored to detect any metastatic disease or other unexpected pathology. The small bowel is then packed into the upper right abdomen, and the sigmoid colon is mobilized. It is usually necessary to mobilize a portion of the descending colon to allow the later construction of a tension-free end colostomy. However, a complete mobilization of the splenic flexure is usually unnecessary. The left ureter and gonadal vessels are identified and preserved by combining sharp and gentle blunt dissection to separate the retroperitoneal tissues from the left colonic mesentery. The sympathetic nerve plexus in front of the aorta is identified and the dissection continues in front of these nerves, just posterior to the inferior mesenteric artery (IMA). There is no consensus on where to divide the IMA. Some surgeons prefer a high ligation at the origin from the aorta and suggest that this maximizes the lymph node yield and may improve oncologic outcomes. Others have a preference for a low ligation just distal to the left ascending colic artery and argue that this ensures a better blood supply to the remaining left colon and may prevent nerve damage at the base of the IMA, resulting in less functional impairment. There is presently not enough evidence to state that one approach is better than the other. After ligation of the IMA or the superior rectal artery and the inferior mesenteric vein at the same level, the sigmoid mesentery is divided, including the marginal artery. The colon at the level of the proximal sigmoid colon is divided with a linear stapler to prevent any fecal contamination.

With restorative procedures in rectal cancer, the dissection continues down to the pelvic floor and puborectalis muscle, and the mesorectum is dissected off the levator muscles. In extended extralevator APR, it is crucial not to take the mobilization of the rectum and mesorectum as far down as the pelvic floor. Instead, the dissection should proceed down to the sacrococcygeal junction dorsally, just beyond the inferior hypogastric plexus anterolaterally, and anteriorly it should stop just below the seminal vesicles in men or the cervix uteri in women. By stopping the mobilization of the rectum and mesorectum at this level, the mesorectum is still attached to the levator muscles of the pelvic floor, which is a crucial feature of the extended extralevator APR. After completion of the dissection down to this level, the abdomen and pelvic cavity are rinsed, preferably with sterile water.

Bowel obstruction, because of entrapment of the small bowel in the pelvic cavity, can be prevented by omentoplasty to fill the pelvic cavity. We prefer to place a drain in the pelvic cavity.

The perineal portion can be performed either with the patient in the lithotomy or prone-jackknife position. We prefer the prone position because of the excellent exposure of the operative field (Fig. 38-1). Some surgeons prefer the lithotomy position, mainly to avoid the time taken to change patient position.

The perineal dissection starts with a double purse string closure of the anus to avoid any spillage of feces or tumor cells. After incision of the skin, the external sphincter is identified and the dissection is continued outside the sphincter up to the levator muscles on both sides. The levator muscles are followed up to the pelvic sidewall (obturator internus muscle) and the external sphincter and levator muscles are exposed around the circumference. The pelvis is now entered, either just below the tip of the coccyx or through the sacrococcygeal junction. At this stage, it is important to identify the mesorectum in order not to injure the mesorectal fascia. The levator muscles are divided on both sides and the division continues onto the prostate or vagina. The specimen is still attached to the anterior aspect of the levator muscles and to the prostate or posterior wall of the vagina.

The dissection in the anterior plane is the most difficult and potentially most dangerous part of the procedure because of the close relationship between the anterior rectal wall and the prostate or posterior vaginal wall. In addition, the neurovascular bundles derived from the inferior hypogastric plexus run anterolaterally on each side of the prostate or vagina and close to the rectum and can easily be damaged if they are not recognized at this stage of the operation (Fig. 38-2). The dissection along the anterior and lateral aspects of the lower rectum must therefore be meticulously performed and with great care. If the dissection is performed too close to the rectal wall, there is a risk of IOP or positive CRM. If the dissection is carried out too laterally, or too anteriorly, there is a risk of damage to the neurovascular bundles or to the prostate or vagina. In anteriorly located tumors, it may be necessary to include the posterior vaginal, the posterior prostate, and the neurovascular bundle on one side with the specimen, and sometimes even to sacrifice to be able to achieve a negative CRM. This extension of the procedure should be based on the preoperative MRI staging and digital examination, and the patient should be well informed about the consequences of bladder and/or sexual dysfunction.