Avoiding lower urinary tract injury
Urogynecologists discuss the rising injury rate, the reasons behind it, and techniques for safe and successful pelvic surgery.
IN THIS ARTICLE
OUR EXPERT PANELISTS
- Moderator Mickey Karram, MD, Director of Urogynecology, Good Samaritan Hospital, Cincinnati, and Professor of Obstetrics and Gynecology, University of Cincinnati.
- Matthew Barber, MD, MHS, Section of Urogynecology and Reconstructive Pelvic Surgery, Departments of Obstetrics & Gynecology and Urology, Cleveland Clinic, Cleveland.
- Alfred Bent, MD, Head, Division of Gynecology, Department of Obstetrics and Gynecology, Dalhousie University, IWK Health Center, Halifax, Nova Scotia.
- Geoffrey Cundiff, MD, Professor of Obstetrics and Gynecology, Johns Hopkins University, Baltimore.
Unfortunate but true: Many complications of pelvic surgery involve injury to the lower urinary tract—and many of these injuries go undetected and increase the patient’s risk of serious morbidity and the physician’s chances of being sued.
Even more unfortunate: These injuries are on the rise, thanks to the proliferation of anti-incontinence surgeries, greater use of laparoscopy, and the need for increasingly complex vaginal dissection.
Fortunately, most lower urinary tract injuries can be avoided, or at least detected early, and this discussion centers on techniques to accomplish those goals and ensure bladder integrity and ureteral patency.
The rising injury rate
There appear to be more injuries to the lower urinary tract arising from pelvic surgery. Why do you think that is?
BARBER: I think the increase is due to the increasing popularity of midurethral slings, such as the tension-free vaginal tape (TVT). With these blind retropubic procedures, the risk of bladder injury is approximately 5%, which is considerably higher than in most other procedures we perform.1
Fortunately, the negative consequences of placing the TVT trocar into the dome of the bladder are minimal, since the trocar can be removed and placed in the appropriate location without the need for bladder repair and without causing long-term bladder dysfunction.
KARRAM: The higher rate of injury also may be linked, in part, to greater use of energy sources during laparoscopic surgery. Over the past 2 years, we have seen numerous cases of delayed injury to the lower urinary tract or bowel secondary to thermal damage from energy devices including electrosurgical instruments and ultrasonic shears.
BARBER: I think there is an increase in lower urinary tract and ureteral injury because of the rising popularity of operative laparoscopy. Lower urinary tract injury is certainly more common with laparoscopic hysterectomy than with abdominal or vaginal hysterectomy.
Increase has no single cause
BENT: There may be a small increase overall in lower urinary tract injury during pelvic surgery, since we now do more procedures that require complicated vaginal dissection and exploration of tissue planes in close proximity to the ureters. This has increased the rate of ureteral injuries.
There also have been a few more urethral injuries, again related to tension-free suburethral slings, most often involving the transobturator approach.
KARRAM: The higher rate of cesarean sections also plays a role. Many women undergoing hysterectomies have had 1 or more cesarean deliveries. We recently completed a study that shows that cesarean section is an independent risk factor for cystotomy at the time of hysterectomy.2
Unfortunately, many surgeons still use aggressive blunt dissection when they attempt to mobilize the bladder off the uterus—whether a hysterectomy is being performed abdominally or vaginally. This can lead to inadvertent entry into the bladder. For this reason, sharp dissection should always be used.
CUNDIFF: Based on my reading of the literature, the incidence of operative injury to the lower urinary tract during gynecologic surgery in general has not changed noticeably since Samson reviewed the subject in 19023—although gynecologic surgery is the leading cause of such injuries and the leading cause of litigation against gynecologists.4
Most injuries involve hysterectomy
CUNDIFF: Most injuries occur during straightforward hysterectomies. Estimates of the prevalence of ureteral injury range from 0.4% to 2.4%.5-8 Since most studies estimating prevalence have not evaluated the lower urinary tract in the whole study population, they may underestimate true prevalence. However, a recent study by Vakili and colleagues9 included universal endoscopy of all patients undergoing hysterectomy and reported rates of ureteral injury (1.7%) and bladder injury (3.6%) similar to those of less rigorous studies.
Overall, the incidence of lower urinary tract injury during other types of urogynecologic surgery is higher than during hysterectomy. Evidence of the higher prevalence during urogynecologic surgery comes from several recent studies. Harris et al10 reported a 5.7% injury rate during reconstructive surgery for incontinence or prolapse. Importantly, 4% were unrecognized prior to urinary tract endoscopy.
Procedures most commonly associated with urinary tract injury were retropubic urethropexy and apical prolapse procedures using the uterosacral ligament in this series. This higher prevalence in urogynecologic procedures may explain the perceived increase in injuries overall.
How can a surgeon prevent bladder or ureteral injury during open hysterectomy?
BENT: Any procedure—regardless of the approach—demands careful dissection, good lighting, and exposure of appropriate structures. It is hard to avoid what you cannot see!
CUNDIFF: When I enter the peritoneal cavity, especially in patients undergoing reoperation, I make the incision more superiorly and avoid the bladder when extending the incision inferiorly. I always open the pararectal space and identify the ureters to ensure their safety during clamping.
Dissection of the vesicovaginal space is most effective when it is done sharply with adequate traction and countertraction. This can be achieved by gently pulling the bladder anteriorly with a Babcock clamp, using scissors to dissect close to the cervix.
For very large fundi, dissection of the vesicovaginal space can be difficult if the uterus is brought through the laparotomy. In these cases I generally take the round ligaments and infundibulopelvic ligaments first and then push the fundus into the upper abdomen. This helps keep the bowel out of the field and gives better visualization of the vesicovaginal space.
I generally enter the anterior fornix with a scalpel and then use Jorgensen scissors to excise the cervix. This helps protect the bladder, and also maximizes vaginal length.
By the way, I use a modified lithotomy position with universal stirrups to maintain access to the bladder for cystoscopy, in case it is needed later.
Follow the ureter
BARBER: During abdominal hysterectomy, I routinely identify the course of the ureter in the retroperitoneum and follow it from where it enters the pelvis until it disappears into the cardinal ligament and below the uterine artery. Following its course helps me avoid ureteral injury.
BENT: If there is scarring of the tube or ovary, or a mass is present, the ureter may have to be localized and dissected completely free of the adnexal structures before any clamps are placed. In addition, the bladder flap should routinely be mobilized using sharp dissection, never blunt dissection.
Mobilization of the bladder downward also pushes the ureters further out of the way during clamping of the uterine vessels. If bleeding occurs, secure hemostasis after observing the location of the ureters. If there is any concern about injury, cystoscopy with injected dye is required.
Next, as the uterosacral and cardinal ligaments are approached, the bladder must be reflected well inferior to this area. This will keep the ureters somewhat removed from the clamps.
Other tricks include performing intrafascial hysterectomy, in which the fascia is peeled away from the uterus and cervix, protecting the ureters.
Clamps placed across the cardinal and uterosacral ligament complexes must hug the uterus and roll off the cervix to protect the ureter.
When the cuff is sutured after removal of the uterus, clear planes of vagina must be seen anteriorly and posteriorly to avoid suturing the bladder into the vaginal cuff.
3 preventive strategies
KARRAM: For abdominal hysterectomy, I recommend 3 techniques:
- Skeletonize the infundibulopelvic ligament. Most surgeons do this routinely during the abdominal approach; I also recommend it for laparoscopic hysterectomy. Once there is a window in the broad ligament and the infundibulopelvic ligament is skeletonized, one can be sure the ureter is well below this area and probably out of harm’s way.
- Use sharp dissection to mobilize the bladder off the anterior cervix.
- Maintain awareness of the close proximity of the lower ureter to the uterosacral cardinal ligament. As the ureter enters the bladder, it can be as close as 1 cm lateral to the uterosacral ligament. This is an area where it is almost impossible to dissect out the ureter, so the surgeon needs to appreciate this anatomy and refrain from taking aggressive bites in the lateral direction when supporting or closing the vaginal cuff.
How can a surgeon prevent bladder or ureteral injury during laparoscopic hysterectomy?
BARBER: I think the ureter is best identified by direct visualization transperitoneally. The angle of the laparoscope makes visualizing the ureter much easier than from an abdominal approach, so retroperitoneal dissection is not necessary as often.
If the course of the ureter is not readily identified by direct transperitoneal visualization, a peritoneal incision can be made below and parallel to the infundibulopelvic ligament, which allows entry into the retroperitoneum and, typically, easy visualization of the ureter throughout its course.
Alternatively, the retroperitoneum can be entered lateral to the infundibulopelvic ligament, and the ureter can be identified in the same manner as in abdominal hysterectomy.
If laparoscopically assisted hysterectomy is planned, I prefer to dissect the bladder flap vaginally rather than laparoscopically, as the risk of bladder injury is considerably lower from a vaginal approach than it is laparoscopically. Obviously, if a total laparoscopic hysterectomy is necessary because of poor vaginal access, laparoscopic bladder flap dissection is necessary. In this case, I again favor sharp dissection and minimal use of cautery to avoid bladder injury.
BENT: Traditional methods in which each clamp is rolled off the cervix or uterus until the procedure is completed help keep unsuspecting surgeons out of the bladder and away from the ureter. The only risk involves bladder mobilization (ie, creation of the bladder flap), which should always be done sharply to prevent bladder perforation. Avoid blunt finger or sponge-stick dissection! Knowing how to sharply dissect the bladder flap is vital—then even cases of prior cesarean section are manageable.
Salpingo-oophorectomy can also proceed under direct vision. Avoid the ureter by making sure the clamp closes only over the pedicles of the tube and ovary, with no intervening tissues in the clamp. If space is very tight, divide the round ligament and take the pedicle in a smaller bite. Traction on the cervix during the procedure, and mobilization of the bladder, allow the ureters to slide upward, well out of harm’s way, as the procedure progresses.
The importance of sharp dissection
BARBER: During vaginal hysterectomy, I usually have the operative assistant hold the cervical tenaculum so that there is tension on the uterus. I then use forceps to elevate the bladder directly vertically in order to place the bladder fibers on tension. Next, I dissect the bladder off the cervix and lower uterine segment using sharp dissection, and identify the peritoneum by direct finger palpation. Almost always, it is smooth and slippery.
After identifying the peritoneum, I grasp it with a tonsil clamp and elevate it so that it can be entered easily with scissors. I always confirm peritoneal entry by visualizing and identifying intraperitoneal structures such as bowel fat, the uterine serosal surface, or adnexae.