Joseph N. Corriere
Department of Urology, University of Texas Medical School, Houston, Texas, USA
Renal Trauma: Blunt injuries account for 90% of all renal injuries. Less than 10% of these patients have associated injuries (usually liver or spleen) and only 2.5% need surgical exploration. Gunshot wounds (8%) and stab wounds (2%) account for the rest of the lesions. However, over 80% of gunshot wounds and less than 40% of stab wounds have associated injuries (liver, chest, bowel, spleen and great vessels), and essentially all of these need surgical exploration.
Diagnosis: On physical examination, signs of upper abdominal and flank trauma, mainly wounds, abrasions, contusions and masses should alert the physician to possible renal injury and suggest imaging studies of the kidneys. Hematuria is present in 98% of the patients with hematuria (2%) will have a renal artery thrombosis due to a deceleration injury.
Imaging Studies – The IVP: In the past, all patients with any degree of hematuria were said to need at least an IVP to rule out a renal injury that required close observation or surgical treatment. In most large series 90% of these IVPs are normal. There are now many series in the literature that detail the risk factors associated with significant renal injuries and allow the clinician to eliminate most unnecessary studies.
In review of 1,103 consecutive patients who had IVPs for suspected renal trauma at the University of Texas Medical School at Houston, we have corroborated these reports. We now recommend an IVP for all patients with penetrating injuries to the flank and abdomen prior to exploration but limit imaging in patients with suspected blunt renal trauma to those with gross hematuria or microhematuria and hypotension (systolic <90) or patients with evidence of major abdominal injury regardless of the blood pressure or urinalysis. (For example: an abdominal physical examination or radiographic evidence of fracture of the 11th or 12th ribs, transverse lumbar processes or pelvis).
In our series, of 862 patients with blunt trauma who underwent IVPs, 70% had only microhematuria and were never hypotensive. Only 60 (10%) of these had abnormal IVPs (49 contusions, 10 minor and 1 major lacerations). Of 241 patients with penetrating trauma and IVPs, 61% had only microhematuria and were never hypotensive. Only 16 (11%) of these had abnormal IVPs (4 contusions, 7 minor and 3 major lacerations and 2 vascular injuries). All major injuries had other reasons (physical findings) to do an IVP. There were 4 patients with blunt injuries and 1 with a penetrating injury that had minor lacerations that would not have studied if the above guidelines had been followed.
Imaging Studies – The CT Scan: If the IVP is abnormal or indeterminate and abdominal exploration is not imminent, a CT scan is the best way to delineate the extent of the injury. Studies now support CT scans with oral, rectal and IV contrast and careful observation in stable pediatric patients and selected adults with blunt trauma as well as back and flank stab wounds. The CT scan gives all of the information necessary for the diagnosis of injury to solid organs. It may miss some bowel lesions. The pattern of contrast extravasation can help in the diagnosis. Lateral extravasation is due to a parenchymal laceration while medical extravasation plus non-visualization of the ipsilateral ureter usually means a collecting system (usually UPJ) disruption.
Remember: What the IVP does best in the trauma patient is tell you the OTHER kidney is normal. The CT scan gives the best definition of the injury but takes more time and is more expensive. Spiral CT scans are, however, faster than an IVP.
Indications for Exploration: Most people still feel all patients with penetrating injuries should be exploded. Perhaps minor stab wounds of the back and flank, using the CT studies described above, can be observed. The absolute indication for renal exploration is a bleeding, expanding, pulsatile hematoma. Relative indications are major extravasation with severe collecting system disruption, non-viable renal tissue, a vascular injury or incomplete staging by the imaging modalities employed.
Intraoperative Technique: Traditional teaching dictates that a large stable or expanding hematoma overlying the kidney hilum and great vessels requires exploration. Only if the hematoma is lateral and away from the kidney can it be left alone. It is usually further stated that prior to entering Gerota's fascia, medical control of the renal pedicle must be accomplished to prevent uncontrollable bleeding from the kidney and needless nephrectomy. Both work at our institution, and the University of Louisville dispute this dictum. When data on the cause for nephrectomy at the time of exploration for trauma is critically analyzed, it is clear that it is not the exploration nor the surgical technique that results in the nephrectomy but the injury itself.
In a review of 85 of our patients who underwent surgical exploration for suspected renal trauma, 33 (39%) had pedicle control prior to entering Gerota's fascia while the other patients had direct exploration of the kidney. In only 6 of these cases (7%), was vascular occlusion actually performed to facilitate the surgery. One patient with a blunt injury and two with gunshot wounds had shattered kidneys and underwent nephrectomies. A nephrectomy was also done on a gunshot wound that destroyed the distal (hilar) segment of the renal artery while a gunshot wound to the distal (hilar) segment of the renal vein as well as a gunshot of the deep hilar parenchyma were repaired.
All of the injuries had not only a hematoma but also a wound over the renal vessels, aorta and vena cava and preliminary vascular control was obtained. This experience as well as the series from Louisville has led us to advocate medial pedicle control first only if a wound and a hematoma overlie the great vessels. Otherwise, reflect the colon and open Gerota's fascia laterally and save up to an hour of operative time. If bleeding is encountered, simple manual parenchymal compression will control the hemorrhage and facilitate repair.
Patients with minor injuries can be treated with simple renorrhaphy, while polar injuries are best treated by partial nephrectomy. Major wounds in the middle of the kidney need major reconstruction. A sheet of Dexon mesh can be sewn into the form of an envelope to oppose the cut surfaces of the renal parenchyma. Nephrectomy is reserved for shattered kidneys.
Ureteral Injuries: The ureter transports urine from the kidney to the bladder. When it is injured it may become obstructed or a fistula may occur and lead to urinary extravasation into the retroperitoneum or the peritoneal cavity. If injury to another structure has occurred at the time of the ureteral injury, a fistula may develop to vagina, skin or bowel. If the urine is infected, life-threatening sepsis may occur.
There are two major types of ureteral injuries – those caused by external violence, usually penetrating missiles, and the more common injuries resulting from surgical misadventure. The late complications of radiotherapy or migrating foreign bodies can also cause injury to the ureter. Gunshot wound account for over 95% of ureteral injuries. Knife wounds are the next most common etiology. Rarely, patients fall and become impaled on a spike.
Ureteral injury may complicate 0.5% to 1.0% of all pelvic operations. Most of these are gynecologic but urinary tract procedures commonly account for 30%. Although radiation injury is often considered when a patient with a previously treated pelvic tumor is found to have ureteral obstruction, the incidence of radiation damage to the ureter is only 0.04%, whereas the incidence of ureteral obstruction caused by recurrent tumor in these patients is over 95%.
The most common migratory foreign bodies that perforate or obstruct the ureter are urinary calculi, bullets, and swallowed objects.
Diagnosis: The IVP is the best way to diagnose a ureteral injury. Urinary extravasation is seen on the study, as well as some decrease in visualization of the collecting system.
If the injury is first seen at surgical exploration, the ureter should be dissected from its bed and examined. If it cannot be positively determined whether an injury is present, one vial (5 ml.) of indigo carmine should be injected intravenously. Within 7 to 10 minutes, the dye will leak into the periureteral tissues if the ureter has been injured.
If the patient is not undergoing exploration, or the diagnosis is not made until many days after the injury has occurred, or if after the IVP there is still a question about the presence of an injury, the most definitive study is a retrograde ureterogram. Most of the time, this study is not feasible. In this case, a CT scan of the area best demonstrates the presence of extravasation. If a CT scan is performed, be sure to get delayed films or a lower ureteral injury (extravasation) may be missed.
Therapy: How to handle a ureteral injury will depend upon the etiology of the injury, how much tissue damage is present and how long it has been since the injury has occurred.
Contusion: This injury is discovered during exploration of a patient who has had a surgical procedure or a missile pass close to the ureter but in whom the structure has remained intact. No therapy is necessary in these patients. If a high-velocity bullet (traveling at a rate of more than 2,500 feet per second) has caused the wound, there is always the danger of late necrosis of the ureter. In this instance, placement of an internal stent and a drain in the area of the injury should be considered. A stent should also be placed if a clamp or ligature has been placed on the ureter, even if it looks “normal” when the obstruction is removed for the same reason.
Laceration: If a partial laceration is present and the ureter that is still in continuity is viable, placement of an indwelling “double-pigtail” stent and closure of the wound with interrupted 4-0 or 5-0 absorbable sutures gives the best result.
If the remaining intact ureter is of questionable viability or if there is a complete laceration of the ureter, all devitalized tissue must be excised and a suitable repair selected.
The ureteroneocystostomy has the lowest complication rate but can be performed only in the patient with an injury below the level of the iliac vessels. The kidney can usually be mobilized and lowered so that the gap between the ureter and bladder can be decreased by an additional few centimeters. A bladder flap can also be used to bring the bladder closer to the ureter. Sometimes merely suturing the bladder to the psoas fascia (psoas hitch) can avoid tension on the repair. Nonrefluxing reimplantation is most desirable but cannot always be performed. If the injury is too high to perform a ureteroneocystotomy, a ureteroureterostomy should be done.
If a major length of ureter is lost, consideration should be given to a transureterouretostomy or merely bring the cut end of the ureter to the skin as a cutaneous ureterostomy for later definitive repair. Autotransplantation of the kidney to the hypogastric vessels plus ureteroneocystostomy should also be considered. This adds major operative time and risk to the patient, but in the patient with a solitary kidney it can be lifesaving.
Ligation: If a ligation (or laceration) of the ureter is not recognized until well after the surgery has been completed, retrograde ureteral catheterization should be attempted. If it is successful, a double-J stent should be placed and the patient observed for resolution of any extravasated urine.
If the retrograde catheterization is unsuccessful, a percutaneous nephrostomy should be placed and an antegrade stent passed into the bladder. After the obstruction and extravasation nephrostomy tube placement should be done, with delayed repair planned months in the future as described above.
In summary, if ligation is diagnosed late in the course of the process, the most conservative approach is to place a percutaneous nephrostomy tube in the kidney and attempt to pass a stent antegrade past the obstruction. If stenting is successful, balloon dilation, in an effort to disrupt the suture, may be tried but is unnecessary. If the ureter has been ligated with chromic suture material, the obstruction will usually resolve in 3 to 4 weeks. If it has been ligated with polyglycolic acid suture, it may take 6 to 8 weeks to resolve. If it has not resolved in 4 to 6 months, formal repair will be necessary.
Presented at the: 13th Saudi Urological Conference Riyadh Armed Forces Hospital 14-17 February 2000 (09-12 Dhu Al Qa’dah 1420)
