The rectum is completely mobilized down to the pelvic floor, applying standard open total mesorectal excision (TME) surgical principles. If the first assistant was between the legs, this person now goes to the left side of the patient for the duration of the rectal dissection. The dissection is commenced with posterior mobilization, working between the fascia
propria of the rectum and the presacral fascia, initially dissecting sharply using electro surgery, the LigaSure device, or alternatively a harmonic scalpel, as far distally as possible (Figure 8.6.11). Dissection is continued posterolaterally to the right and left sides of the rectum, dividing the flimsy peritoneum overlying the proximal rectum, carefully and continuously sweeping the hypogastric nerves trunks posteriorly and laterally. The laparoscopic magnification provided by nearly all types of scopes provides 15-20 x magnification, and this certainly affords excellent views of the pelvic structures, including theses nerves.
If the proper plane is entered posteriorly, no bleeding will occur, and the connective tissue in this plane can be divided easily (Figure 8.6.12). The assistant provides traction by using the left hand grasper to pick up the cut edge of the peritoneum on the right side of the rectum, and the right hand grasper is opened and used to lift the mesorectum anteriorly and superiorly, separating it from the anterior sacrum. The cycle of dissecting posteriorly, laterally first on the right and then on the left is repeated over and over until the tip of the coccyx and beyond is reached, without any significant anterior dissection being done yet.
The lateral stalks are most usefully divided using the LigaSure device, although the Harmonic Scalpel may also be a useful tool. Both have the advantage over standard electrosurgery in that less smoke is generated,
and larger vessels may be closed using them. The LigaSure may be useful for nearly all vessels encountered in the pelvic dissection. Care is taken to separate the pelvic nerve plexus from the rectum at the level of the lateral stalks, unless there is suspected direct tumor invasion at this level (Figure 8.6.13).
The anterior plane, at the pelvic cul-de-sac, is struck usually after most of the posterior and lateral dissection has been completed. The first assistant uses the left hand to retract the anterior portion of the reflection anteriorly, and the right hand to retract the rectum superiorly and posteriorly, whereas the surgeon uses the left hand to retract the rectum medially (for the right side of the dissection) and the right hand is dividing tissue using the LigaSure or similar device. The key manuever is to go from "known to unknown," usually meaning posterior to lateral, and to avoid dissecting into the vagina or through Denonvilliers' fascia unless the tumor is infiltrative there. It may be highly useful to use the surgeon's doubly gloved hand, passed into the anus or vagina from the perineum, to sound out the vagina or rectum at this point, in order to remain in the proper plane at all times (Figure 8.6.14).
Once the surgical team is confident that dissection has been performed circumferentially to the pelvic floor, the surgeon should again put on a second sterile glove over the right hand, and place this hand into the rectum (and in women, the vagina) to perform bimanual palpation in order to confirm complete rectal dissection to the pelvic floor level.
Was this article helpful?