We have divided the procedure into four parts: ureterolysis, dissection of the rectovaginal septum, excision of the rectovaginal nodule, and reconstruction.
When the ureters and bowel are involved with the disease process, the surgical approach should take into account the importance of restoring normal anatomy. The use of uterine manipulators with a colpotomy cup can help delineate the posterior vaginal fornix and the rectum. The introduction of rectal and vaginal probes during the surgery will improve the exposition and excision of the lesions (see figure above).
After pneumoperitoneum is established and maintained at 15 mm Hg, we have used a standard technique of placing a 10-mm trocar in the umbilicus for the laparoscope and three 5-mm ancillary trocars. One 5-mm trocar is placed to the right at 10 cm lateral to the umbilicus, and two 5-mm trocars are placed to the left (10 cm lateral to the umbilicus and in the left lower quadrant).
A thorough examination of the abdomen and pelvis should be performed to assess the disease and degree of dissection needed to successfully access the rectovaginal space. To excise the lesions, we have used the bipolar RoBi forceps (Karl Storz), monopolar scissors, and the Harmonic scalpel.
Ureterolysis
In all of our cases thus far, ureterolysis was performed before resection of any DIE nodules. The ureter crosses the pelvic brim close to the bifurcation of the common iliac artery, at which point it becomes the pelvic ureter. It continues on the pelvic sidewall medial to the infundibulopelvic ligament as it crosses the external iliac artery. Branches of the internal iliac artery supply the descending portion of the ureter and move along the course of the ureter from the lateral aspect.
The dissection of the ureter begins at the pelvic brim where the anatomy is normal. The peritoneum superior to the ureter is grasped and entered, and the incision is extended. Medial traction is placed on the inferior edge of the peritoneal incision, and dissection is continued in the fat/nonfat interface until the ureter is identified.
The ureter is surrounded by a layer of loose areolar tissue; this layer is entered by using a blunt dissector to dissect parallel to the ureter. Small vessels should be coagulated in the process to ensure visibility. The ureterolysis is directed toward the uterosacral ligaments and continued until the ureter enters the cardinal ligament (see photo above).
When complete obliteration of the cul- de-sac is present and the uterosacral ligaments are obscured bilaterally, ureterolysis is carried out on the opposite side to improve pelvic anatomic restoration. The dissection is sufficient when both ureters are mobilized completely and when each can be traced from the pelvic brim to its insertion into the bladder (see photo above).
Dissection of Rectovaginal Septum
The next step is to enter and dissect the rectovaginal septum. Prior to excision of the nodule, the pouch of Douglas is first accessed by freeing the area from any adhesions or ovarian endometriomas.
After the successful bilateral ureterolysis, the ureters can be identified and the posterior fornix can be delineated with the rectal probe and colpotomizer.
The posterior fornix is then pushed upward, and a transverse incision is made over the posterior cervix superior to the rectum—an area also known as the prerectal fascia (see photo above).
The rectovaginal septum extends laterally from the posterior cervix and uterosacral ligaments to the pelvic sidewall, where it then courses caudally to insert in the perineal body. This area is dissected inferiorly until the uterosacral ligaments (also known as the medial rectal pillars) are identified. At this stage, the ureter, the pararectal space, the lateral rectal pillar with associated nerves, and the medial rectal pillar are seen. The rectal probe will then help identify the rectum and the dissected uterosacral ligaments in their respective planes.
The potential space medial to the ureter is used to transect the uterosacral ligament and thus enter the rectovaginal space from the lateral aspect to medial. The uterosacral ligament is again transected, and the rectovaginal space entered (see photo above).
If the dissection is continued too superiorly, the prerectal fascia is transected and the vagina may be entered. If this occurs, then the fascia is retracted superiorly and the rectum is retracted inferiorly to help identify the correct dissection plane.
By understanding the anatomic principle that fat belongs to the rectum, one can identify the fat/nonfat interface; this facilitates dissection superior to this plane. It is also important to maintain the integrity of the vaginal and rectal spaces as much as possible to decrease the risk of bowel perforation. The dissection is continued until the space is fully developed.