Abstract
Ureteral injuries present a challenge to the urologic surgeon because their treatment requires a thorough knowledge of anatomy, mechanism of injury, and reconstruction techniques. The ureter can be divided into the proximal, middle, and distal ureter, although often management of long or multi-segment injuries is required. Mechanisms of ureteral injury include iatrogenic causes and blunt or penetrating trauma. The surgical management of ureteral injuries may include endoscopic intervention, ureteral reconstruction, or in some cases nephrectomy. Often, more than one procedure is needed. Increasingly, robotic-assisted approaches for reconstruction are utilized, while open and laparoscopic techniques remain important in the surgeon’s armamentarium. In appropriate cases, long-term nephrostomy tube or ureteral stent placement may be considered. Ultimately, the goals of management for ureteral injuries are to restore quality of life and preserve renal function.
Keywords
Ureter, Ureteral injury, Urine leak, Urinoma, Ureteral stricture, Hydronephrosis, Ureteral trauma
Chapter Outline
Strategies for the Management of Ureteral Injuries
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Key Points
- 1.
An understanding of the anatomy of the ureter, including its course and blood supply, is necessary for successful management of ureteral injury.
- 2.
Timely and accurate diagnosis of the ureteral injury, including the etiology and extent of injury, is critical for minimizing sequelae and facilitating repair.
- 3.
The key principles of ureteral reconstruction include isolation of viable tissue, tension-free anastomosis, and intraluminal stent drainage in the short-term postoperatively.
Introduction
When injury to the ureter occurs, the passage of urine from the kidney to the bladder is disrupted. Timely recognition is important to avoid renal deterioration and morbidity. Management of ureteral injury is often elective, but may require emergent intervention. Therefore it is important that the urologic surgeon is prepared to manage injuries that may occur along the entire length of the ureter. The primary aims of management include restoring quality of life, preserving renal function, and minimizing complications including urinoma, fistula, infection, and stricture.
Anatomy
Between the renal pelvis and the bladder, the course of the ureter travels through the retroperitoneum posterior to the colonic mesentery. The ureter can be divided into the upper, middle, and lower segments. From proximally to distally, the 22- to 30-cm ureter travels anterior to the psoas muscle, under the gonadal vessels as they cross from medial to lateral about 2–3 cm below the inferior margin of the kidney, over the iliac vessels at the bifurcation of the common iliac artery, and into the pelvis, where it enters the bladder trigone. Two good locations to identify the ureter are over the iliac bifurcation and lateral to the gonadal vessels at the level of the lower pole of the kidney. The blood supply of the ureter is segmental and enters the proximal ureter medially and pelvic ureter laterally ( Fig. 14.1 ). The vascular plexus of the ureter is located in the adventitia. Branches that supply the ureter are difficult to visualize and arise from the renal, gonadal, lumbar, aorta, and iliac arteries. The layers of the ureter include the urothelium, lamina propria, smooth muscle (longitudinal and circular), and surrounding adventitia.
Etiologies of Ureteral Injury
Ureteral injuries can be classified by their etiologies, which most commonly include iatrogenic causes or blunt or penetrating trauma.
Iatrogenic causes often include endoscopic trauma during the management of stone disease. Urinary stone impaction may predispose to additional injury to the ureter, leading to submucosal, extraluminal, or a Steinstrasse pattern that may eventually lead to the development of a ureteral stricture. Ureteroscopic misadventure may lead to perforation, avulsion, or mucosal tears. Forgotten or neglected encrusted ureteral stents may also lead to ureter stricture. A history of retroperitoneal or pelvic radiation for malignancy may predispose to ureteral stricture. Complications related to gynecologic surgery including hysterectomy may lead to ureteral ligation or injury that may be initially recognized or at a delayed presentation ( Fig. 14.2 ). Abdominoperineal resection, hemicolectomy, and other colorectal procedures may predispose to distal ureteral injuries. Neurosurgical and orthopedic procedures of the spine may also injure the ureter. Vascular grafts and repairs may injure the mid-ureter ( Fig. 14.3 ).
Furthermore, several systemic illnesses may necessitate ureteral reconstruction. These include infection (tuberculosis, schistosomiasis), primary ureteral malignancy, ureteral fibroepithelial polyps ( Fig. 14.4 ), and retroperitoneal or pelvic cancer with extrinsic invasion. Other benign diseases that affect the ureter include retroperitoneal fibrosis, inflammatory bowel disease, aortic and iliac aneurysms, ovarian vein entrapment, and pelvic lipomatosis.
External trauma to the ureter can be divided into blunt and penetrating trauma. It is critical to note that ureteral injuries in these settings are frequently associated with concomitant injuries in other organ systems, so these also need to be explored. For penetrating trauma (gunshot wounds), it is important to know the caliber of the weapon, as higher penetrating velocities have greater collateral damage. During emergent exploration, the ureter can appear normal, but over time tissue necrosis can result. Penetrating nongunshot wounds such as knife wounds rarely have delayed tissue necrosis. It is important to visualize all sides of the potentially injured ureter. Blunt injuries may involve rapid deceleration, and the ureteropelvic junction is at risk for avulsion most commonly seen in children. Ureteral injuries associated with blunt and penetrating trauma are further reviewed in Chapter 15 .
Diagnosis
The diagnosis of ureteral injury includes not only identifying the nature and extent of injury, but also assessment of the kidneys and bladder as a priority. It is important to know the overall renal function and account for the presence and condition of the contralateral kidney. The presence of bladder outlet obstruction, a small capacity bladder, and/or dysfunctional voiding may affect the outcome of the repair.
Intraoperative identification and direct inspection of the ureter allow for the characterization of the ureteral injury. Indigo carmine or methylene blue can be directly injected into the ureter or through a nephrostomy tube to determine if a leak is present. Retrograde pyelography can be performed to determine the area of extravasation, obstruction, or narrowing that would suggest a stricture. Intravenous pyelography can be performed in a trauma setting to evaluate the contralateral kidney. Tricks to identify the ureter intraoperatively include identification of the rhythmic peristalsis of the ureter with or without squeezing the ureter with forceps, movement of a previously placed yellow angiographic exchange catheter, or lighted ureteral catheters. The best method for identifying the ureter is to rely on anatomic knowledge. Two reliable areas are located anterior to the iliac bifurcation and lateral to the gonadal vessels at the level of the lower pole of the kidney.
Most often, urologic imaging is best performed by the treating urologist, which allows for the assessment of the location and length of the injury. Retrograde imaging can delineate the status of distal ureteral pathology and evaluate the contralateral ureter. If a nephrostomy tube is present to protect renal function, antegrade imaging can be performed to delineate the extent of the proximal disease ( Fig. 14.5 ). During cystoscopy, one can quantify capacity and compliance of the bladder and infer evidence of bladder outlet obstruction.
Anatomic imaging with computer tomography (CT) with delayed contrast imaging can be used to evaluate penetrating trauma with hematuria or any suspicion of genitourinary injury. If nonenhanced contrast CT is performed, data are limited to the renal parenchymal thickness, status of the retroperitoneum and pelvis, and adjacent structures. MRI has the benefit of no ionizing radiation delivered and detection of hydronephrosis; however, it is a poor modality for stone detection and is limited in cases of low GFR (<40 mL/min) to administer gadolinium due to the risk of nephrogenic systemic fibrosis. Delayed contrast imaging can provide information regarding the level of ureteral injury.
The length and location of the stricture is an initial marker for the type of repair feasible. Strictures >2 cm in length are unlikely to be resolved with endoscopic techniques. For segments ~2 cm, a ureteroureterostomy can be considered, with a centimeter on either side of the lesion needed to provide healthy tissue. For distal strictures or strictures of 4–5 cm, a ureteroneocystotomy can be performed. For 6- to 10-cm defects in the mid- to distal ureter, a psoas hitch can be considered. For 12- to 15-cm mid- to distal ureteral defects, a Boari bladder tube flap +/- combination with a psoas hitch can be considered. For repairs >15 cm or proximal defects, bowel interposition or autotransplant can be performed. Renal mobilization has been described to gain additional ureteral length; however, in our experience, mobilization of the kidney does not gain much length at the level of the proximal ureter.
Additional factors to consider for the affected kidney are the parenchymal thickness and the presence of incidental, asymptomatic hydronephrosis or symptomatic hydronephrosis. It is important to have an understanding of the function of the contralateral kidney, presence of systemic diseases, and related infection or pyelonephritis if present, and to be able to rule out malignancy as a source of the obstruction.
Timing of Repair
A critical decision for surgeons is determining the optimal timing of repair relative to the timing of the injury. This decision is heavily influenced by how quickly the ureteral injury is recognized. In cases of delayed recognition, often local inflammation, urinary extravasation, intraabdominal adhesion of bowel distention, and/or the presence of infection may serve as obstacles to successful immediate repair. These factors contribute to failed repair owing to the condition and mobility of the tissues, and often delayed repair is warranted.
In the setting of an intraoperatively recognized ureteral injury, immediate repair is generally warranted in the absence of hemodynamic instability of medical compromise of the patient. In cases of ureteral laceration, debridement of devitalized tissue, followed by primary repair or selection of an appropriate reconstructive procedure is usually carried out. In cases of ureteral ligation, primary reimplantation, with or without ureteral interposition, is indicated. If the patient is unstable, then a temporizing maneuver to achieve proximal urinary drainage, with a plan to return at a delayed interval for definitive repair, is appropriate. In such cases, proximal drainage can be achieved by stent placement, or nephrostomy, depending upon the severity of the injury, and the patency of the distal ureter. In cases of ureteral transection, surgeons have often considered ureteral ligation with proximal nephrostomy drainage as a temporizing maneuver. It should be noted that devitalized ureters often break down leading to ureteral leakage or fistula, despite intraoperative ligation. Drainage of the ureteral injury site to ensure control of any delayed extravasation is wise.
When ureteral injury is not identified intraoperatively, but becomes evident 48–72 hours postoperatively, immediate repair can be considered, depending upon the mechanism of injury, severity of extravasation, and the medical condition and emotional state of the patient. Many patients are not mentally prepared for immediate return to the operating room or may be having difficulty with recovery. In these cases, temporizing maneuvers to relieve obstruction, drain extravasated urine, and achieve proximal diversion are very reasonable. In the case of a patient who is motivated for rapid resolution of the problem, has minimal to no urinoma collection, and is medically fit, early repair is an appropriate consideration. Beyond 72 hours, edema and local inflammatory reaction leading to friability of the tissue may lead to a lower likelihood of successful repair. In these cases, or in cases of more delayed recognition of the injury, immediate repair is not wise. Proximal drainage and control of any urinary fistula are warranted. Surgical repair may be delayed for 6–12 weeks to allow the injured region to scar in place and local inflammation to resolve completely. At the time of delayed repair, placement of an antegrade catheter to the point of the injury may aid in intraoperative identification of the injury.
Preoperative Management
Before repair is attempted, it is important to carefully document the location, length, and nature of the injury. It is important to define expectations and anticipate potential complications, and ask the questions, is the ureteral reconstruction likely to succeed or should a nephrectomy be performed? Can the reconstruction be performed in situ or does a backtable repair with autotransplant need to be considered to optimize success?
A ureteral injury worth repairing is dependent on the function of the ipsilateral and contralateral kidney and the age and overall health of the patient. The patient’s cardiovascular status, anesthetic risk, and life expectancy should be considered. As a general rule, if the kidney can provide ~20% of the overall renal function, then it is worth saving. In other words, would the contralateral kidney support life if the kidney in question were removed? Relieving ureteral obstruction will rarely increase ipsilateral renal function; however, it will prevent further deterioration. Isotopic nuclear renography can provide information on renal split function if the kidney parenchyma appears marginal, and also the isotopic retention and excretory slope may indicate a patulous collecting system or presence of obstruction.
In the trauma setting, the primary goal is first achieving hemodynamic stability followed by identification of injuries. There may be situations where a ureteral injury cannot be initially repaired due to hemodynamic instability or the poor or uncertain condition of the ureteral tissue. It may be necessary to ligate the ureter immediately proximal to the site of injury, place a nephrostomy tube, and return in a delayed setting for repair.
The timing of the repair should allow for optimization of nutrition and other systemic diseases, including diabetes mellitus, hypertension, and anticoagulation status. Drainage of the kidney can be temporized with a nephrostomy tube or a ureteral stent if continuity can be established. If definitive ureteral repair is planned but a ureteral stent is indwelling, the ease of the repair will be dramatically improved if the stent is removed at a minimum of 3–4 days prior to the procedure to allow for resolution of tissue edema. A sterile urine culture should be documented prior to reconstruction.
If the morbidity of reconstruction or nephrectomy outweighs the chance of success, permanent nephrostomy tube drainage or a chronic double J stent can be considered. A downside of this approach is the discomfort related to these tubes and the need for frequent ureteral stent or nephrostomy tube changes to avoid encrustation. A metal Resonance stent or tandem ureteral stents can be considered as alternative options.
Strategies for the Management of Ureteral Injuries
Beyond an understanding of the anatomy, location, length, and type of ureteral injury, what is most important to approaching the management of ureteral injuries is an understanding of the nuances and limitations of each technique ( Fig. 14.6 ). Here, we present technique-related tips and tricks in the management of ureteral injury based on our experience. We separate the endoscopic approaches from the reconstructive techniques based on ureteral location. A complete guide to how to perform specific techniques or procedures can be found in several excellent atlases and references ( Hinman’s Atlas of Urologic Surgery, Glenn’s Urologic Surgery, Campbell’s Urology ) and will not be repeated here. Furthermore, whether the repair is performed using open, laparoscopic, or robotic-assisted approaches is less important than the approach with which the surgeon is most facile.
The key principles of ureteral reconstruction include isolation of viable and healthy ureteral tissue, tension-free anastomosis, and intraluminal ureteral drainage with a ureteral stent for approximately 6 weeks. We generally perform refluxing repairs on all reconstructive cases because the goal is to minimize the risk of a future stricture, and usually there is a paucity of tissue to mobilize. We typically place a drain near the ureteral repair in the short term and a Foley catheter to prevent reflux and an overdistended bladder to facilitate drainage of the upper tracts.
Endoscopic Repair
The primary indication for endoscopic repair is for a short segment ureteral stricture. Endoscopic approaches can be divided into stricture incision or dilation. The major advantage of these techniques over other reconstructive techniques is their minimal morbidity. Classically the ideal patient has a short, focal stricture ≤1 cm in length. For dense, longer strictures >1 cm in length, the rate of failure is high.
Balloon dilation of the stricture is relatively straightforward, but several key points should be emphasized ( Fig. 14.7 ). Retrograde pyelography should be obtained to fully identify the stricture, and the C-arm fluoroscopy unit should not be moved to ensure one can identify the stricture in relation to fixed boney landmarks. It is essential to pass the guidewire beyond the stricture. Initially a hydrophilic guidewire (straight or coude tipped – with or without a locking torque device) can help successfully pass the guidewire. It should be exchanged over an angiographic exchange catheter to place a nonhydrophilic guidewire to limit unintended dislodgement. In addition, ensure that that balloon profile is as tight as possible prior to back-loading it onto the wire so that it will most easily traverse the stricture. Inflate the balloon with contrast under fluoroscopy to ensure the balloon straddles the stricture.
Endoscopic stricture incision can be performed with a holmium laser or the Acucise device for endopyelotomy or endoureterotomy. The direction of the cut is critical to avoid injury to surrounding structures. If the stricture is proximal near the ureteropelvic junction, aim lateral. If the stricture is located near the iliac vessels, aim anterior. The holmium laser allows for more precision, as this is performed under direct vision. The laser should be passed beyond the stricture and cut as it is withdrawn. Laser settings should use a high frequency with low-power energy settings. The goal is to visualize the stricture “pop” open to allow visualization of fat, representing a transmural cut. The Acucise device can be deployed similarly, and, again, it is important to ensure that the balloon straddles the stricture. We typically initially fill the balloon with 1.0 mL and visualize the stricture under fluoroscopy and then cut for 5 seconds as one fills the balloon to a total of 2.2 mL. We recommend a 75-watt pure cut setting. If there is a concern whether the cut has occurred, after device removal there should be a characteristic cautery smell along the cutting wire. If the device needs to be reused, be aware that the profile of the balloon may be too large to successfully pass through the strictured segment. A nice trick is to use the writing on the Acucise port to guide the direction of the cut – if a lateral cut is desired, the writing should also be lateral. Finally, in our experience, we find that the cut is less effective if there is a high contrast concentration present. We therefore use dilute contrast during the initial retrograde pyelography. Finally, the 7/10Fr Acucise endopyelotomy stent can be placed for 4–6 weeks. It has no sideholes to prevent tissue ingrowth and narrowing of the lumen. Alternatively one can use a traditional 8–8.5Fr double J stent or a Schueller ureterotomy stent set manufactured by Bard (Covington, GA). This ureteral stent has an adjustable sleeve with a wider caliber that can be placed at the location of the stricture. It is widely used in Europe and is used less frequently in the United States.
As an aside, ureteral avulsion has been reported during ureteroscopy, especially early in the adoption of the technique. In these cases, when this injury has been identified, it is best to stop the case, place a nephrostomy tube, and decide to come back at a later time to address the ureter. This is the time to regroup, talk to the patient and his or her family, and avoid a rash procedure (usually late at night). After the patient has been temporized with a nephrostomy tube, it is important to inform the patient what to expect from the different reconstruction options, and after a decision has been made on which repair to perform, it is important to assemble the right team to perform a definitive repair.
Proximal Ureteral Repair
Ureteral reconstruction in the proximal ureter or ureteropelvic junction can often be challenging. The key to a successful outcome is achieving a tension-free anastomosis. It has been described that renal mobilization can provide additional mobility of the proximal ureteral segment; however, in our experience, mobilization of the kidney does not gain much length. Additional factors that may complicate repair include surrounding hilar vessels, severe scarring, and a small intrarenal pelvis. Endoscopic endopyelotomy has been previously discussed, and it is best performed for short segment focal stricture ≤0.5 cm in length. Longer strictures can be treated; however, increasing stricture lengths have a higher failure rate in our experience.
A number of reconstructive techniques have been described for the ureteropelvic junction and proximal ureter, but one needs to be selective about which approach is best warranted dependent upon anatomy. These include the Foley Y-V pyeloplasty, Anderson-Hynes dismembered pyeloplasty ( Fig. 14.8 ), Fenger pyeloplasty employing the Heineke–Mikulicz technique, and use of different flaps created from a dilated, redundant renal pelvis. If a crossing vessel is present, a Hellstrom procedure can be considered, where the vessel is mobilized and displaced away (typically cephalad) from the area of obstruction using a hammock of surrounding fascia or fat. For the dismembered techniques, it is critical that a wide spatulation is performed on both ends of the anastomosis to avoid stricture recurrence. We place interrupted, absorbable sutures to allow coaptation of tissue. In general, it is easiest to close the back wall of the anastomosis first, followed by ureteral stent placement, and then completion of the anterior wall.
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