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Low anterior resection of rectal cancer


Step 1 – Trocar insertion and diagnostic laparoscopy

  • Trochar insertion with visiport just to the right of and at the level of umbilicus. A further 12 mm port in the right fossa, one in the midline about 5 cm above the umbilicus, one 5 mm in the left fossa, and one 12 mm suprapubically. Avoid the inferior epigastric vessels and insertion of the caudal trochars too low on the abdomen which may impede the angulation within the abdominal cavity.
  • Examine the primary tumor for perforation and/or infiltration into adjacent organs. Thereafter the liver and the total abdominal cavity is inspected with regard to metastases, peritoneal carsinomatosis (especially the pelvis and the paracolic gutters) and other pathology.

Step 2 – Release the left transversal colon, left flexure and descending colon

  • The patient in Trendelenburg’s position tilted towards the right. Position the omentum over the liver and put the small bowel package over the midline to the right. If necessary apply an extra trochar suprapubically to expose the Treitz ligament.
  • Open the peritoneum on the posterior abdominal wall medially to the origin of the inferior mesenteric artery after taking down possible adherances at the ligament of Treitz.
  • Continue in the mesocolic plane towards the left flexure and divide the inferior mesenteric vein. Dissect in the mesocolic plane cranially (avoid dissection posterior to the pancreas) and continue anteriorly to the pancreas and into the lesser sac. Be aware that archadic vessels can be located relatively centrally along the colon.
  • Divide adherances along the tail of the pancreas all the way to the lateral abdominal wall. Continue behind the left flexure and descending colon (in front of the pancreas and the left kidney).
  • In front of the colon the gastro-colic ligament is divided just caudally to the gastro-epiploic vessels, divide the splenocolic ligament.
  • Divide the peritoneum laterally to the descending colon along “the white line of Tod”. Carry through till the anterior and dorsal dissections have met and the left flexure and descending colon are completely free.

Step 3 – Central resection of the inferior mesenteric artery.

  • Lift sigmoid and its mesentery anteriorly and to the left and put it on tension.
  • Incise the peritoneum at the pelvic entrance till the origin of the inferior mesenteric artery in the gutter between the posterior abdominal wall and the sigmoid mesentery.
  • Continue in the posterior mesocolic plane behind the sigmoid mesentery towards the lateral abdominal wall (avoid left ureter).

A. Cancer of the upper rectum (>12 cm)

  • Dissect the origin of the inferior mesenteric artery at the aorta and divide with hemlock.

B. Cancer in the middle/lower rectum

  • Dissect the inferior mesenteric artery at the origin of the left colic artery and further along this to the ascending branch of the left colic artery (the inferior mesenteric vein is located close to this crossing).
  • The inferior mesenteric artery is divided with hemlock just distal to the origin of the left colic artery. Possible branches of this artery are divided while the main stem of the left colic and ascending branch are left intact to assure an adequate circulation of the left colon/ sigmoid. Fat with lymph nodes may be dissected off central parts of the superior mesenteric area and removed en-bloc with the lymph nodes at the origin of the left colic artery.
  • During this dissection the main sympathetic nerves must be visualized and retracted posteriorly to avoid injury. Avoid dissection into the parietal fascia in front of the aorta and posterior abdominal wall. If the proper vessel wall is visualised the dissection has been carried on too deeply and the nerve plexus may have been injured.

Step 4 – Finish the dissection of the sigmoid.

  • Grip the divided mesenteric inferior artery and lift it forward.
  • Continue the dissection in the mesocolic plane till the lateral abdominal wall behind all  the descending colon till the pelvic entrance. Carefully sweep the nerves posteriorly.
  • From the anterior dissect the sigmoid until the left colon, sigmoid and the upper rectum is completely free.

Step 5 – Total mesorectal excision

  • Extend the peritoneal incision on the posterior abdominal wall (medially) down to rectovesical pouch.
  • Incise the peritoneum transversally in front around 1 cm above the pouch. In female the dissection is performed along the dorsal wall of the vagina.
  • Tips: The proper plane may be difficult to identify on the top of the vagina. With a swab on a stick in the vagina this can be lifted up and forward to simplify the anatomy. In male the wall of the vesicles should be identified and followed on is posterior aspect and further on behind the prostate. It is recommended that the dissection from above is initially stopped 1-2 cm down behind the prostate, the rest can be performed after the posterior dissection.
  • Continue presacrally on to the rectum in the dissection plane developed behind the sigmoid which is the mesorectal plane (Heald’s holy plane”).
  • Dissect in this plane on the outside of the mesorectal fascia from 3-9 o’clock (4-8) as far down as possible. The dissection is then continued from the front and eventually the areas 2-3 and 9-10 are divided.
  • The dissection often has to be performed shifting from dorsally- anteriorly- laterally but the aim should be to go far down behind before continuing in front leaving the lateral dissection lastly. An initial presacral dissection permits the rectum to be lifted up and forward which facilitate the rest of the dissection. The plane is most difficult to identify laterally which is where the nerves are most frequently injured.
  • Fulfilment of the distal dissection.

Step 6 – Low anterior resection

  • For tumor of the upper rectum the mesorectum is dissected 5 cm anally to the lower border of the tumor.
  • Continue right angled through the mesorectum to the bowel tube at the proper level, thus avoid coning in on the specimen which will render the anal resection margin less than 5 cm.
  • For tumor in the middle/lower rectum the dissection is continued all along to the pelvic floor, and if desired further on to the upper part of the anal canal.
  • Prepare a free bowel wall along the whole circumference. Flush the rectum.
  • Divide the rectum with stapler and try to leave the row of staplers perpendicular on the bowel and close it with one magazine of staplers. More staple shots increase the chance of leakage. Avoid Z-lines.

Situations can develop when it is impossible to divide the bowel sufficiently far anally. Conversion to an open procedure should then be performed.

Transanal-TME (ta-TME)

  • The dissection from above is finished at the level of the middle rectum.
  • The dissection from below is performed up to this level.

Step 7 – Exteriorization of the specimen and division of the oral bowel tube.

  • Make a 6 cm incision transversally above the symphysis (Pfannenstihl incision).
  • Incise the fascia in front of the rectus muscle similarly.
  • Lift both edges of the fascia with Kocker’s forceps and dissect it off the underlying muscle. The dissection must be sharp in the midline.
  • Retract both rectus muscles from the midline.
  • Incise the peritoneum.
  • Apply plastic protection to the edges of the wound and exteriorize the specimen with the central vessels.
  • Divide mesentery and bowel at intended location.
  • Cut with scissors in the vascular arcade close to the bowel to visualize adequate blood circulation in the oral bowel end (adequate systolic blood pressure during the test?). Move further orally on the colon in case of inadequate bleeding.
  • Insert the “hat” of the circular stapler and close with a purse-string suture.
  • Interiorize the colon.
  • Close the abdomen.

Step 8 – Anastomosis

  • Insert the circular stapler very carefully and perforate the bowel with the pin just in front of or behind the staple row.
  • Attach oral and anal parts of the stapler while controlling the rotation of the bowel. Close the stapler and visually control for possible interposition. Fire the stapler.
  • Test the anastomosis enclosed by water and with air in the rectum.
  • Retract the omentum over the small bowel.

Step 9 – Laparoscopic control and closure of ports.

  • Repeat inspection of the abdominal cavity for possible iatrogenic injury.
  • Close the ports.

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