Ureteric Injury

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1273 Ureteral injury is not uncommon in pelvic surgery. In fact, 75% of all ureteral injuries occur during gynecologic surgery, with the majority of these injuries occurring dur- ing abdominal procedures. 1 Previous studies have re- ported a 0.4% to 2.5% rate of injury during benign pelvic surgery and only a third of these injuries were recognized at the time of surgery. 2 Consequently, the actual inci- dence of intraoperative ureteral trauma can be much higher. Even though the risk of injury is significantly higher in surgeries involving invasive cancer and urogy- necologic procedures, all pelvic surgeons must become familiar with the causes and risk factors associated with this preventable complication. In this article, we reviewed the anatomic considerations, etiologic factors, risk fac- tors, clinical presentation, prevention, and management of ureteral injuries sustained during pelvic surgery. Anatomic considerations To prevent injury to the ureter, the pelvic surgeon must become familiar with the anatomic features of the ureter and areas where it is most susceptible to trauma. Ureters are retroperitoneal tubular structures measuring approx- imately 25 to 30 cm in length, extending from the renal pelvis to the urinary bladder. 1,3-5 The right ureter is ap- proximately 1 cm greater in length than the left ureter. The abdominal portion of the ureter lies on the anterior surface of the psoas muscle, descending posterolaterally as it crosses over the iliac vessels. The right ureter con- tacts the descending portion of the duodenum anteriorly, running along the right aspect of the inferior vena cava. The left ureter lies posterior to the left colic vessels and passes posterior to the mesentery of the sigmoid colon. As the ureter approaches the pelvis, it is crossed anteri- orly by ovarian vessels. The right ureter enters the pelvis by crossing over the external iliac artery while the left ureter crosses over the common iliac artery. At this point, the ureter lies medial to the branches of the anterior di- vision of the hypogastric artery and lateral to the peri- toneum of the cul-de-sac. At the midplane of the pelvis, the ureter is crossed anteriorly by the uterine artery. Here it tunnels into the cardinal ligament, approximately 1.5 to 2.0 cm lateral to the cervix near the internal cervical os and vaginal fornices as it enters into the trigone of the bladder. 3 Histologically, the ureter is composed of three concentric layers that include an inner layer composed of transitional epithelium, a middle layer of circular and smooth muscle, and an outer layer of adventitial sheath. 1,3,4 The adventitial layer contains the arterial sup- ply, nerve supply, and lymphatics of the ureter. Thus, it is important to maintain the integrity of the adventitial sheath during dissection of the ureter. To prevent is- chemic injury to the ureter, one must also become famil- iar with its unique blood supply. The renal artery, ovarian artery, common iliac artery, and the aorta all contribute blood supply to the ureter. In the abdomen, the ureter derives its blood supply from small arteries approaching it medially, whereas the pelvic ureter receives its blood supply from vessels approaching laterally. 1,3 Because the vessels interface with the peritoneum, attempts should al- ways be made to preserve the peritoneum with the ureter during dissection. Thus, the peritoneal incision to expose the ureter should be made laterally to the ureter in the abdomen and medially in the pelvis. From the Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Chao Family Comprehensive Cancer Center, University of California, Irvine, Medical Center. Received for publication January 16, 2003; accepted January 16, 2003. Reprint requests: Alberto Manetta, MD, Division of Gynecologic Oncol- ogy, Department of Obstetrics and Gynecology, Chao Family Comprehen- sive Cancer Center, University of California, Irvine, Medical Center, 101 The City Drive, Orange, CA 92868. E-mail: [email protected] © 2003, Mosby, Inc. All rights reserved. 0002-9378/2003 $30.00 + 0 doi:10.1067/mob.2003.269 Prevention of ureteral injuries in gynecologic surgery John K. Chan, MD, Joelle Morrow, MA, and Alberto Manetta, MD Orange, Calif Pelvic surgery is the most common cause of iatrogenic ureteral injury. The majority of patients with ureteral injuries have no identifiable predisposing risk factors. A simple maneuver that has been taught successfully at our institution that facilitates the identification of the ureter is described. When injury is discovered during surgery, correction of the injury can be repaired with minimal risk of long-term sequelae.Postoperatively, patients with ureteral injury typically present with costovertebral angle tenderness, ileus, fever, and flank pain with a minimal rise in serum creatinine.To prevent ureteral injuries, the surgeon must have a thorough knowledge of the location of the ureter during various pelvic procedures and the specific regions where it is most susceptible to injury. (Am J Obstet Gynecol 2003;188:1273-7.) Key words: Ureteral injury, gynecologic surgery, diagnosis, treatment, prevention

Transcript of Ureteric Injury

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1273

Ureteral injury is not uncommon in pelvic surgery. Infact, 75% of all ureteral injuries occur during gynecologicsurgery, with the majority of these injuries occurring dur-ing abdominal procedures.1 Previous studies have re-ported a 0.4% to 2.5% rate of injury during benign pelvicsurgery and only a third of these injuries were recognizedat the time of surgery.2 Consequently, the actual inci-dence of intraoperative ureteral trauma can be muchhigher. Even though the risk of injury is significantlyhigher in surgeries involving invasive cancer and urogy-necologic procedures, all pelvic surgeons must becomefamiliar with the causes and risk factors associated withthis preventable complication. In this article, we reviewedthe anatomic considerations, etiologic factors, risk fac-tors, clinical presentation, prevention, and managementof ureteral injuries sustained during pelvic surgery.

Anatomic considerations

To prevent injury to the ureter, the pelvic surgeon mustbecome familiar with the anatomic features of the ureterand areas where it is most susceptible to trauma. Uretersare retroperitoneal tubular structures measuring approx-imately 25 to 30 cm in length, extending from the renalpelvis to the urinary bladder.1,3-5 The right ureter is ap-proximately 1 cm greater in length than the left ureter.The abdominal portion of the ureter lies on the anterior

surface of the psoas muscle, descending posterolaterallyas it crosses over the iliac vessels. The right ureter con-tacts the descending portion of the duodenum anteriorly,running along the right aspect of the inferior vena cava.The left ureter lies posterior to the left colic vessels andpasses posterior to the mesentery of the sigmoid colon.As the ureter approaches the pelvis, it is crossed anteri-orly by ovarian vessels. The right ureter enters the pelvisby crossing over the external iliac artery while the leftureter crosses over the common iliac artery. At this point,the ureter lies medial to the branches of the anterior di-vision of the hypogastric artery and lateral to the peri-toneum of the cul-de-sac. At the midplane of the pelvis,the ureter is crossed anteriorly by the uterine artery. Hereit tunnels into the cardinal ligament, approximately 1.5to 2.0 cm lateral to the cervix near the internal cervical osand vaginal fornices as it enters into the trigone of thebladder.3 Histologically, the ureter is composed of threeconcentric layers that include an inner layer composed oftransitional epithelium, a middle layer of circular andsmooth muscle, and an outer layer of adventitialsheath.1,3,4 The adventitial layer contains the arterial sup-ply, nerve supply, and lymphatics of the ureter. Thus, it isimportant to maintain the integrity of the adventitialsheath during dissection of the ureter. To prevent is-chemic injury to the ureter, one must also become famil-iar with its unique blood supply. The renal artery, ovarianartery, common iliac artery, and the aorta all contributeblood supply to the ureter. In the abdomen, the ureterderives its blood supply from small arteries approachingit medially, whereas the pelvic ureter receives its bloodsupply from vessels approaching laterally.1,3 Because thevessels interface with the peritoneum, attempts should al-ways be made to preserve the peritoneum with the ureterduring dissection. Thus, the peritoneal incision to exposethe ureter should be made laterally to the ureter in theabdomen and medially in the pelvis.

From the Division of Gynecologic Oncology, Department of Obstetricsand Gynecology, Chao Family Comprehensive Cancer Center, Universityof California, Irvine, Medical Center.Received for publication January 16, 2003; accepted January 16, 2003.Reprint requests: Alberto Manetta, MD, Division of Gynecologic Oncol-ogy, Department of Obstetrics and Gynecology, Chao Family Comprehen-sive Cancer Center, University of California, Irvine, Medical Center,101 The City Drive, Orange, CA 92868. E-mail: [email protected]© 2003, Mosby, Inc. All rights reserved.0002-9378/2003 $30.00 + 0doi:10.1067/mob.2003.269

Prevention of ureteral injuries in gynecologic surgery

John K. Chan, MD, Joelle Morrow, MA, and Alberto Manetta, MD

Orange, Calif

Pelvic surgery is the most common cause of iatrogenic ureteral injury. The majority of patients with ureteralinjuries have no identifiable predisposing risk factors. A simple maneuver that has been taught successfullyat our institution that facilitates the identification of the ureter is described. When injury is discovered duringsurgery, correction of the injury can be repaired with minimal risk of long-term sequelae. Postoperatively,patients with ureteral injury typically present with costovertebral angle tenderness, ileus, fever, and flank painwith a minimal rise in serum creatinine. To prevent ureteral injuries, the surgeon must have a thoroughknowledge of the location of the ureter during various pelvic procedures and the specific regions where it ismost susceptible to injury. (Am J Obstet Gynecol 2003;188:1273-7.)

Key words: Ureteral injury, gynecologic surgery, diagnosis, treatment, prevention

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Cause of injury

Intraoperative injury to the ureter may result from liga-tion, angulation, transection, laceration, crush, ischemia,and resection.6 The most common site of operative in-juries to the ureter during routine abdominal hysterec-tomy or adnexectomy is at the pelvic brim, where theureters lie beneath the insertion of the infundibulopelvicligament. Other common locations are over the iliac ar-teries, within the cardinal ligament at the level of the in-ternal cervical os where the uterine artery crosses theureter, and at the anterolateral fornix of the vagina as theureter enters the bladder (Fig 1). In urogynecologic pro-cedures (ie, Marshall-Marchetti-Krantz cystourethropexyor retropubic urethropexy), ureteral injuries usuallyoccur near the ureterovesical junction. During vaginalhysterectomy, the ureter can be traumatized near the in-ternal cervical os and vaginal fornices as it enters into thetrigone of the bladder7 (Fig 2). In laparoscopic surgery,particularly during ablation of endometriosis, the mostcommon site of ureteral injury is near the uterosacral lig-aments, which have become thickened as a result of en-dometriosis.8 In the obstetric patient, ureteral injury canoccur as a result of suturing an extended uterine incisionin an effort to control bleeding within the broad ligamentduring a cesarean hysterectomy or in the process of per-forming a hypogastric artery ligation.

Risk factors

Although most ureteral injuries occur in patients whohave no identifiable risk factors, there are certain condi-tions that increase the likelihood of ureteral injuries, par-ticularly those that disrupt the normal anatomy andarchitecture of the ureters. These conditions include en-dometriosis, large ovarian masses, and pelvic inflamma-tory disease.6 Two large studies have retrospectivelyreviewed the incidence of ureteral injuries and its associ-ated risk factors. These authors found that pelvic malig-nancies were present in 44% of the cases and appear tobe a significant risk factor associated with ureteral injury.This is most likely related to the presence of tense adhe-sions, large masses that displace the ureter, and anatomicchanges distorting the position of the ureters. Other riskfactors include previous pelvic surgery, broad ligament fi-broids, and history of pelvic radiation.9,10 Other less com-mon factors that predispose a patient to ureteral injuryinclude congenital abnormalities such as ureteral dupli-cation, megaureter, and ectopic ureter or kidney. How-ever, it is noteworthy that half of all ureteral injuries hadno identifiable predisposing factors.6,9

Preventing ureteral injury

Abdominopelvic surgery. The best way to prevent injuryto the ureter is to routinely identify its path through thepelvis and the regions where it is most susceptible to in-jury. A detailed illustration has been provided depicting

the areas where the ureter is most susceptible to injuryduring abdominopelvic surgery (Fig 1). The ureter mustbe identified through an incision that provides adequateexposure to prevent iatrogenic injury. The peritoneum isopened lateral to the infundibulopelvic ligament, and theureter is identified on the medial leaf of the peritoneum.A simple maneuver described by Manetta et al11 that fa-cilitates the identification of the ureter involves the fol-lowing steps. After dividing the round ligament near thelateral pelvic sidewall, the lateral peritoneum is opened10 to 15 cm in a cephalad direction. An index finger isthen placed on the external iliac artery, which can beidentified easily from its superficial, consistent anatomicposition and pulsating characteristics. If one then movestheir finger upward (cephalad), the first structure to beexposed, crossing and in contact with the iliac artery, willbe the ureter. As the surgeon places an index finger onthe ureter, the infundibulopelvic ligament should be be-hind the middle phalanx. In this manner, the infundibu-lopelvic ligament can be safely clamped with the ureterunder direct visualization. The ureter is subsequently fol-lowed toward the cardinal ligament, where it passes underthe uterine artery. If one needs to dissect the ureter awayfrom harm, it is important to preserve the normal bloodsupply to the segment of the ureter found in the lowerpelvis or on the level of the intravesical wall. Stallworthy12

recommends preservation of the mesentery to the ureterby carefully dissecting the ureter from the pelvic wall lo-cation while preserving its attachment medially to theperitoneum. This thin mesentery of fibrofatty tissue andsmall blood vessels contributes to the ureteral blood sup-ply by branches from the hypogastric.12 Although dissec-tion or mobilization of the ureters may not be indicated,the ureters should be clearly identified in the abdomen orpelvis, particularly in areas where it is most susceptible toinjury. To distinguish the ureter from other vascular struc-tures, the ureter will typically elicit peristalsis on gentlestroking. Others have observed that the ureter has a char-acteristic snap when it is gently palpated.1,3,6,13 Previousstudies have revealed that attention to the anatomiccourse of the ureter during pelvic surgery is more effec-tive in preventing injury than preoperative intravenouspyelograms (IVP) or ureteral stent placements.14,15 Al-though its usefulness is debatable, IVPs have been usedpreoperatively to locate the ureters for surgery in patientswith disease processes that may distort the ureters, such aspelvic masses or inflammatory disease. In a study of 493patients undergoing vaginal and abdominal hysterec-tomies, Piscitelli et al16 found that preoperative abnormalIVP findings to be associated with patients who had an en-larged uterus ≥12 weeks’ gestational age or ovarianmasses 4 cm or greater. On the other hand, incidence ofabnormal IVP findings was not increased in patients withendometriosis, pelvic inflammatory disease, pelvic relax-ation, or a history of previous pelvic surgery. Most impor-

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tantly, preoperative IVPs did not decrease the incidenceof ureteral injuries.16 Retrograde ureteral catheters,which are used to help identify ureters for dissection,were also found to have questionable value in the preven-tion of intraoperative ureteral injury. In a review of 3071major gynecologic surgeries, in which 15% underwent bi-lateral prophylactic ureteral catheterization, Kuno et al14

found that prophylactic ureteral catheterization did noteliminate the risk of ureteral injuries. Clearly, the best de-fense against ureteral injury is meticulous surgical tech-nique and identifying the course of the ureter and theassociated anatomic locations where injury is most likelyto occur.

During abdominal hysterectomy, the ureter can be visu-alized by opening the anterior leaf of the broad ligament.The ureter is surrounded by loose avascular fibroconnec-tive tissue. Once exposed, the ureter is gently pushed later-ally and downward, moving it away from the cervix. This

maneuver protects the ureter and with traction on theuterus also exposes the uterine artery. However, endome-triosis and/or pelvic inflammatory disease may disfigurethe region where the ureter crosses the uterine artery at themidplane of the pelvis. Furthermore, large broad ligamentor cervical leiomyomas may obscure the operative field,making the dissection extremely difficult.

Vaginal surgery. A detailed figure has been provideddepicting the areas where the ureter is most susceptibleto injury during vaginal surgery (Fig 2). During vaginalhysterectomy or surgery for pelvic floor relaxation, onemust develop an adequate vescicouterine space to protectthe ureters from injury by surgical clamps and sutures.This is achieved by downward traction on the cervix andcountertraction upward beneath the bladder. It is impor-tant to clamp, cut, and ligate only small bites of paracer-vical and parametrial tissue adjacent to the uterus. Thesesteps are critical to ensure that the ureters stay safely away

Fig 1. Ureteral injury in abdominopelvic surgery.

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from the operative field.1 The ureters can be palpated byapplying gentle traction on the cervix, combined with up-ward traction on the upper vagina exposing the entrypoint of the ureter into the trigone.17

Anterior colporrhaphy. During anterior colporrhaphy,the surgeon must be careful not to start too laterally or toinsert the sutures too deeply to prevent needle injury to theureters while plicating the bladder. In fact, Hofmeister18

found that the distance between the ureter and the sur-

geon’s needle in the upper third of the vagina is only 0.9 cmduring anterior colporrhaphy using fluoroscopic imaging.

Intraoperative diagnosis of ureteral injury. If ureteralinjury is suspected intraoperatively, the surgeon mustpromptly identify the ureter and evaluate the severity andnature of the injury. If the injury cannot be adequately vi-sualized, an intravenous injection of indigo carmine canhelp confirm and identify the location of the ureteral in-jury. If urine passed into the Foley catheter is blue, one

Fig 3. Clinical management of ureteral injury.

Fig 2. Ureteral injury during vaginal surgery.

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can only be certain that one of the ureters has not beenligated. Furthermore, failure to visualize the passage ofblue urine into the bladder via cystoscopy suggests occlu-sion of one or both ureters.

Postoperative clinical evaluation. Ureteral trauma canbe easily missed, particularly in the case of unilateralinjury. If the contralateral kidney is healthy, it will com-pensate for the loss with only a transient rise in creati-nine.7 Eventually the affected kidney will lose its function.Early postoperative diagnosis of ureteral injury typicallytakes place 7 to 10 days after surgery.1 Symptoms includecostovertebral angle tenderness, ileus, fever, and flankpain, indicating a hematoma, inflammation, or infectionat the site of injury. An IVP and cystoscopy should be per-formed if ureteral injury is suspected to locate and char-acterize the injury. Because immediate dissection may bedifficult, retrograde ureteral cathether placement andnephrostomy drainage may obviate the need for surgicalintervention.4

Practical treatment of ureteral injury

The approach to ureteral repair depends on thecause, location, and extent of the injury. A detailed flow-chart on the clinical management of ureteral injury hasbeen provided in Fig 3. Minor trauma, such as ligatureor crush injuries may be managed with stent placementand drainage of the affected area. Stents remain inplace for approximately 6 weeks, followed by an IVP toensure ureteral patency. Partial transections are typi-cally corrected by suture repair or resection of the af-fected segment. Clearly, damage to a greater portion ofthe ureter requires a more involved repair. A crush in-jury or transection in the middle portion of the uretercan be repaired by an end-to-end anastomosis.1,7 To en-sure a tension-free anastamosis, it may be necessary tofree the ureter from its peritoneal attachments or bymobilizing the kidney. Also, a psoas hitch can add sev-eral centimeters of length to the ureter. In this proce-dure, the bladder is sewn to the psoas tendon and theureter is reimplanted through a submucosal tunnel intothe bladder. Injuries near the bladder can be repairedby direct implantation of the ureter into the bladder orthrough a submucosal tunnel; the latter technique isless likely to be associated with vesicoureteral reflux. In-juries in the middle or upper third of the ureter can berepaired by a ureteroileoneocystotomy, where a bridgebetween the ureter and the bladder is made from a seg-ment of the terminal ileum.

Outcomes of ureteral injury

Minor injuries to the ureter can be reversed intraopera-tively without any long-term sequelae. However, necrosedsegments of ureters can lead to a weakened ureteral wall,resulting in extravasation of urine into periureteral tissues.A urinoma may develop, which can become infected and

lead to an abscess. Alternatively, urine can accumulate inthe peritoneal cavity leading to urinary ascites and peri-tonitis.7 Last, as a result of injuries during vaginal surgery,ureterovaginal fistulas may develop. Uremia typically re-sults from damage to both ureters. Bilateral ureteral liga-tion presents as anuria during the first 24 to 48 hours inthe postoperative period and later develop a rise in bloodurea nitrogen and creatinine levels. Immediate urinarydrainage, through nephrostomies, may be necessary toreestablish normal renal function.

Comment

The majority ureteral injuries are associated with pelvicsurgery. The gynecolologic surgeon must become famil-iar with the anatomy of the abdominal and pelvic ureterand the locations where is it is most susceptible to injury.Clearly, prevention is the best defense against ureteraltrauma.

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