The first step of the procedure consists in grasping the inferior mesenteric vein, which correspond to the first anatomical landmark, and dissecting adhesions between the vein and the proximal jejunum. The primary dissection of the vein from the posterior attachments is particularly useful to identify the plane of dissection of the told fascia, and to dissect the upper border of the inferior mesenteric artery. This step avoids pitfalls during the artery dissection. In order to facilitate the inferior mesenteric artery (IMA) ligation, the second anatomical landmark is the presacral area. Once the vein is completely free, the dissection continues by the exposition of the presacral area using a grasper placed on the sigmoid mesentery giving an optimal view of the promontory. An incision of the peritoneum is performed exactly 2 cm in front of the promontory allowing the beginning of the dissection of the upper part of the mesorectum, which is also the distal part of the IMA. To insure the good plane of dissection, the ‘angel hairs’ of the mesorectal space are opened and the proximal mesorectum is dissected posteriorly on a few centimeters. The objective is to connect by an horizontal incision the area of the proximal part of the mesorectum and the area located under the vein already dissected. This step allows identifying the artery exactly 2 cm from the aorta in order to preserve the sympathetic nerves and facilitate the end of the dissection of the IMA by using an accurate instrument (Fig. 50.4a). The IMA must be completely free before performing ligation or transection. A various kind of ligation can be used such as clips, suture or modern devices. Thermal fusion can be used in vessels no more than 7 mm without calcification, but requires to stop any tension of the artery before transecting to avoid incomplete sealing. After IMA ligation, the next step is left colonic mobilization.

Both surgeon and assistant push up the mesentery to dissect the told fascia via a medial approach. The dissection using scissors begins in the left iliac fossa, preserving the gonadal blood vessels and the left ureter. The advantage of the medial approach is an optimal view and exposure of the planes of dissection. The told fascia dissection is continued as high as possible, especially in front of the Gerota’s fascia and close to the splenic flexure. During this step, the IMV is preserved and served as potential landmark to identify the pancreas. By dissecting from the posterior approach, the incision of the transverse mesentery permits to identify the pancreas and to enter in the lesser sac. In some difficult cases, the complete dissection of the terminal part of the IMV improves the view of the pancreas giving the plane to open the lesser sac. The complete anterior dissection of the pancreas makes the transverse mesentery totally free and finishes the medial approach. The IMV is then transected close to the pancreas, or 5 cm below if a left transverse colic artery is visualized in this area, to avoid colonic ischemia. The last part of colonic mobilization is the lateral mobilization. By pushing the sigmoid on the right, a peritoneal incision is performed along the left border of the sigmoid, including the rectosigmoid area. The division of the lateral peritoneum continues along the descending colon and finishes at the splenic flexure. In order to avoid splenic decapsulation, adhesions of the greater omentum and the splenocolic ligament must be dissected. The medial approach greatly facilitates this last step of mobilization.

The first step of the dissection of the mesorectum is the high posterior dissection. This extra facial anatomical dissection of the mesorectum can be performed by using scissors and monopolar coagulation, harmonic scalpel (Ultracision^TM, Ethicon Endosurgery, Cincinnati, Ohio, USA) or thermal fusion (Ligasure^TM, Covidien, Mansfield, Massachusetts, USA). The rectum exposure is achieved by pulling up vertically the rectum using a supra-pubic grasper. The anatomical landmarks are the retrorectal space medially, and the hypogastric nerves laterally. The dissection begins medially 2 cm in front of the sacral promontory and continues caudally and posteriorly at 45 °C along the presacral area, using scissors. The good plane of dissection is located between the mesorectum (yellow tissue) and the presacral fascia (gray tissue). The medial dissection must be stopped 10 cm below the promontory at the level of the retroscral ligament corresponding to the fusion between the presacral and the mesorectal fascias. Adequate tension to the tissues facilitates dissection. Non-traumatic instruments are used without grasping the mesorectum to preserve its integrity. This medial posterior dissection avoids injuries of both superior hypogastric plexus and hypogastric nerves.

The second step is the right lateral dissection after identification of the hypogastric nerves. A cephalic traction of the superior hypogastric plexus at the sacral promontory level induces tension of the hypogastric nerves, which can be visualized as a “fiber” through the soft pelvic tissues or below the peritoneum. An incision of the peritoneum along the right side of the rectum is performed down to the anterior reflection. Lateral pelvic dissection from the hypogastric nerve to the presacral area is then performed connecting the previous medial high posterior dissection. After full right lateral mesorectum mobilization, the same dissection is performed on the left side.

The third step consists in the high anterior dissection. Seminal vesicles in men and cervix in female are the landmarks, which need to be identified. The upper rectum is grasped with cephalic and left lateral traction giving a tension to the opposite anterior and right sides of the rectum. A peritoneal incision is performed anteriorly 2 cm above the Douglass pouch and connects the lateral right incision performed during the previous step. Distal dissection from 1 to 2 cm of right anterior peritoneum allows discovering the right seminal vesicle, which must be completely isolated. In order to preserve both small efferent nerves along the vesicles and the mesorectum which is very thin and fragile at this level, the dissection must be lead close to the seminal vesicles. In female, pelvic exposure is facilitated by uterus fixation to the anterior abdominal wall by using a supra-pubic stitch. The anterior incision of the peritoneum permits to identify the cervix and then to connect the high lateral dissection.

The fourth step is low lateral dissection using the inferior hypogastric plexus as anatomical landmark. The objective is to transect the lateral ligament of the rectum. By following dissection along a virtual line between the seminal vesicle and the hypogastric nerve, the pelvic plexus appears as a 2–3 cm triangle located along the lateral sidewall of the pelvis. To free the mesorectum from the pelvic plexus, some attachments due to vessels and nerves coming from the plexus to the mesorectum have to be cutted. To prevent from plexus injury, perfect hemostasis and adequate traction of the tissue are essential.

Then, the rectum is pulled up for optimal visualization of the low pelvis. After incision of the rectosacral ligament, dissection is continued distally and posteriorly along the levator ani muscle. Presacral nerves (S2–S4) are identified at the mid part of the sacrum and preserved by dissecting close to the mesorectum. For a sphincter saving procedure, the dissection is performed until the top of the anal canal. For an APR, dissection is stopped earlier at the coccyx to avoid disconnection between tumor adhesion and levator ani muscles.

The end of the TME procedure consists in dissecting anteriorly and caudally taking care not to injure Denonvilliers’ fascia, the seminal vesicles, the prostate and the vagina. This last step is particularly challenging in men. The oncologic low anterior dissection must be performed in front of the Denonvilliers’ fascia, which can be considered as the anterior part of the mesorectum. Care is taken to do an anatomical dissection which preserves both the Denonvilliers’ fascia and the anterior mesorectum, which needs to be removed together to achieve a radical oncologic laparoscopic TME excision.

For high and mid rectal cancer, the rectum is transected 5 cm below the lower edge of the lesion [20], achieving respectively a partial or a total mesorectal excision. After full mobilization of the rectum, pushing on the perineum facilitates rectal division. Stapler is introduced by the 10 mm supra-pubic port (Fig. 50.5a) [46]. The specimen is then removed from a supra-pubic 6 cm incision. A wound protector is necessary to decrease risks of port-site and local recurrences. Reconstruction with a colonic pouch or a straight colorectal anastomosis is performed laparoscopically (Fig. 50.5b). A colonic pouch is performed if the rectal stump is shorter than 5 cm. The quality of the anastomosis is checked by the completeness of the doughnuts and by a transanal air test.

In low rectal cancer, a low colorectal stapled anastomosis could be very difficult to perform laparoscopically, especially for men, narrow pelvis, and bulky tumors. The alternative is to perform a manual coloanal anastomosis instead of stapled anastomosis which can compromise oncologic margins and anastomosis healing. For very low tumors, intersphincteric resection is used to achieve sphincter preservation with safe distal margin [47]. The low pelvic dissection during the laparoscopic coloanal procedure can be achieved either by the laparoscopic approach or by the perineal approach. In both approaches, rectal transection is performed transanally. The anal canal is exposed by a self-holding retractor (Lone Star Retractor®, Lone Star Medical Products Inc., Houston, TX). The specimen is removed through the anal canal except for thick mesentery or anal stricture, and a hand-sewn side-to-end coloanal anastomosis is performed (Fig. 50.6). For the first laparoscopic approach, surgical procedure was previously described. For the first perineal approach, instead of doing high rectal dissection laparoscopically followed by dissection of the low rectum through the perineum, the procedure begins by a transanal perineal step [48]. A gauze was introduced into the rectum to limit the risk of seeding. The rectum was transected at least 1 cm below the lower edge of the tumor. Then, rectum was closed transanally by suture to avoid intraoperative tumor spillage and facilitate exposure. The perineal dissection of the low rectum was performed transanally along the levator ani muscles. The plane of dissection began into the intersphincteric plane and continued posteriorly to the sheath of the pelvic floor for at least 5 cm. The sheath of the levator ani muscles, which was usually thickened due to irradiation, was then transected to join the plane of the abdominal dissection. Thus, the perineal dissection permitted to dissect as far as possible from the distal rectal wall, where the mesorectum is usually lacking, and therefore to maintain optimal distance between the tumor and surgical resection. The perineal dissection was conducted posteriorly and anteriorly up to 10 cm from the anal verge. It was easier in female than in male due to the shorten length of the anal canal in the former. After the perineal dissection of the distal rectum, a conventional laparoscopic procedure is performed. Surgery is usually easier and faster due to previous low rectal dissection. The primary transanal perineal step represents an interesting surgical alternative option to avoid problems associated with stapling and to decrease the rate of conversion to an open procedure.

A presacral suction drain and a temporary loop ileostomy are used in all TME procedures. The loop ileostomy is closed 8–12 weeks after surgery.