OBGM_0806_Hatch.final 7/21/06 11:06 AM Page 17 SURGICALTECHNIQUES THE RETROPERITONEAL SPACE Keeping vital structures out of harm’s way Knowledge of the retroperitoneal space is critical, to avoid unnecessary blood loss and injury of the ureter, bladder, bowel, and nerves he accomplished gynecologic sur- Kenneth D. Hatch, MD The “landmark” Professor, Department geon must know the anatomy of of Obstetrics and Gynecology, T the retroperitoneal space in order umbilical ligament Arizona Health Sciences Center Tucson, Ariz to avoid damage to normal structures, as® Dowden Health Media well as remove pathology. Many disease The umbilical ligament was the umbilical processes involve the pelvic peritoneum, artery in fetal life and courses along the uterosacral ligaments, rectosigmoidCopyrightFor or edgepersonal of the bladder use to theonly anterior abdom- ovarian pedicles, and require the surgeon inal wall up to the umbilicus. It is a useful to enter the retroperitoneal space to iden- guide into the perivesicle space. Lateral to it tify the ureters and blood vessels and are the iliac vessels, and medial is the blad- keep them out of harm’s way. The chal- der. It is also a good marker for finding the IN THIS ARTICLE lenges are complex: right spot to open the round ligament. • Badly distorted anatomy and the ante- ❙ Endometriosis may rior and posterior cul-de-sac necessi- imperil the ureter tate mobilization of the rectosigmoid Page 20 and bladder. • Intraligamentous fibroids require ❙ Preventing ureteral knowledge of the blood supply in the retroperitoneal space. Malignant disor- injury ders mandate that the lymph nodes be Page 23 dissected to determine extent of disease and as part of treatment. ❙ Protecting pelvic nerves ❚ Is training adequate? Page 24 Every training program should teach the FIGURE 1 surgical anatomy of the retroperitoneal Opening the round ligament space, since every surgeon needs to be over the umbilical ligament comfortable exposing the anatomy, both The round ligament is the key to exposing to prevent injury and to accomplish the the retroperitoneal space. It should be open needed surgery. Videotapes and cadaver at the pelvic sidewall, just medial to the courses can prepare the resident for the external iliac vessels. The umbilical ligament operating room. can be used as a landmark. CONTINUED www.obgmanagement.com August 2006 • OBG MANAGEMENT 17 For mass reproduction, content licensing and permissions contact Dowden Health Media. OBGM_0806_Hatch.final 7/21/06 11:06 AM Page 18 ▲ Keeping vital structures out of harm’s way The “landmark” umbilical ligament continued FIGURE 2 FIGURE 3 Opening lateral Right pelvic sidewall anatomy to the ovarian vessels Medial traction of the peritoneum around the The divided round ligament is retracted ovarian vessels at the pelvic brim will expose ventrally and medially to place the ovarian the ureter coming over the iliac vessels at vessels under traction. The peritoneum lateral their bifurcation into external and internal to the ovarian vessels is divided up to the branches. pelvic brim. FAST TRACK The ureter and anterior branch of the internal iliac artery are nearly parallel as they course through the pelvis FIGURE 4 FIGURE 5 Relationship of ureter Hypogastric nerve to the umbilical ligament The anterior branch of the internal iliac artery The ureter comes off medial with the fold gives off the uterine artery and the middle of peritoneum. Once the space is developed, and superior vesicle arteries before continu- the operator’s finger or the laparoscopic ing on as the umbilical ligament. probe can be introduced along the medial side of the internal iliac artery and ventral to the curve of the sacrum. This will open the pararectal space. The ureter and the anterior branch of the internal iliac artery are nearly parallel as they course through the pelvis. CONTINUED 18 OBG MANAGEMENT • August 2006 OBGM_0806_Hatch.final 7/21/06 11:07 AM Page 20 ▲ Keeping vital structures out of harm’s way Endometriosis may imperil the ureter Endometriomas and peritoneal implants are among the most common reasons for access- ing the retroperitoneal space. Frequently the peritoneum between the ovarian vessels and the uterosacral ligaments (ovarian fossa) is thickened and retracted within the endometrio- sis implants. This alters the pelvic anatomy and puts the ureter at risk for injury. Definitive surgical treatment for endometriosis includes removal of this diseased peri- toneum. The ureter is best identified using the technique described, and then dissected off the peritoneum down to the uterine artery. FIGURE 6 FIGURE 7 Finding the ureter Relationship of ureter lateral to an endometrioma to the umbilical ligament FAST TRACK Definitive surgical treatment of endometriosis includes removal of the diseased peritoneum FIGURE 8 FIGURE 9 Dissecting the ureter Divide uterine artery out of the uterosacral ligament lateral to endometrioma The ureter may be placed on a Penrose drain Here, the uterine artery is taken lateral to the to better isolate it and keep it under direct mass, enabling the surgeon to remove all of visualization. The cul-de-sac of Douglas is the uterosacral implants. The bladder flap will another site of endometrial implants. The fun- be developed and the bladder advanced dus of the uterus is often adhesed to the rec- caudad. By dissecting medial to the ureter as tosigmoid reflection and even the sigmoid it courses under the uterine artery, it will be colon. Nodules of endometriosis may infiltrate retracted laterally and provide the space nec- the uterosacral ligaments and extend into the essary to resect the uterosacral implants. rectovaginal space. To manage these implants, isolate the ureter to the point where it passes under the uterine artery. CONTINUED 20 OBG MANAGEMENT • August 2006 OBGM_0806_Hatch.final 7/21/06 11:07 AM Page 23 Keeping vital structures out of harm’s way ▲ Endometriosis may Preventing imperil the ureter continued ureteral injury Ureteral injuries occur in 0.5% to 2.5% of women undergoing gynecologic surgery.1 The most common predisposing condition is previous pelvic surgery.2,3 The usual sites of injury are at the pelvic rim close to the ovarian vessels, at the level of the uterine artery, and lateral to the vaginal cuff. Neither preoperative excretory urograms nor placement of ureteral catheters preoper- atively have been found to be effective pre- FIGURE 10 vention measures.2,4–6 Using the steps Rectosigmoid reflection described above, the ureter can be identified with endometrioma nodule and mobilized. Blood supply to the ureter comes from the plexus of vessels that form a network along the length of the ureter. This plexus is fed by arteries from the renal pelvis, com- mon iliac, internal iliac, uterine artery, and the base of the bladder. Complete mobiliza- tion of the ureter away from its peritoneal attachments and these lateral blood supply sources can be accomplished as long as the vascular plexus is not disrupted by cautery, crushing, or tearing. A clean transection can be re-anastomosed or reimplanted with FAST TRACK the expectation of normal healing. FIGURE 11 Common sites Innervation of the ureter is from the inferi- Postoperative appearance or mesenteric plexus superiorly and the of ureteral injury: of endometriosis resection inferior hypogastric plexus in the pelvis. ❙ at the pelvic rim As dissection proceeds medially, use the Ureteral peristalsis will continue, even if the perirectal fatty plane to remove implants ureter is completely divided or ligated. near the ovarian between the uterosacral area and rectum. In vessels the midline, remove implants below the rec- tosigmoid peritoneal reflexion, taking care not ❙ at the level of the to injure the rectum. Protecting pelvic uterine artery Implants above the peritoneal reflexion blood vessels are often attached to the sigmoid tinea coli ❙ lateral to and cannot be removed without taking a portion of the bowel. Thus, patients with The majority of gynecologic operations the vaginal cuff extensive endometriosis should have a bowel involve the ovarian vessels and the uterine prep with two 10-ounce bottles of magne- vessels. The operator rarely needs to sium citrate the day before surgery. explore the lateral pelvis to identify the rest If bowel resection is necessary, consult a of the vessels. When faced with a large general surgeon or gynecologic oncologist. endometrioma or cancer, knowledge of the A history of painful defecation or a finding of anatomy of the lateral blood vessels is vital. nodules in the cul-de-sac with rectal dimpling Since the pathology is usually deeper in warrants preoperative consultation with a the pelvis, it is wise to identify the anatomy specialist skilled at bowel resection. of the pelvis starting at the pelvic brim, www.obgmanagement.com August 2006 • OBG MANAGEMENT 23 OBGM_0806_Hatch.final 7/21/06 11:07 AM Page 24 ▲ Keeping vital structures out of harm’s way where the common iliac bifurcates into Hypogastric artery ligations are rarely the external and internal iliacs. There is a performed today, as interventional radiolo- safe dissection plane medial to the internal gy is the standard of care for patients with iliac artery all the way to the uterine postoperative and postpartum bleeding. artery. This exposes the pararectal space, When it becomes necessary, the hypogastric which can be opened without risk of artery can be isolated and tied using the major bleeding (FIGURE 5). right-angle clamp to pass the tie. The supe- The obliterated umbilical vessel is the rior gluteal artery branches so close to the other friendly marker just distal to the uter- bifurcation of the common iliac artery that ine artery. It can be placed on traction and it is not visualized. The inferior gluteal the uterine artery isolated. The inferior and artery is the largest distal branch, which superior vesical arteries are generally not might be visualized during the ligation. It is dissected, as they are adjacent to the blad- not necessary to identify it.