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Traumatic Injuries of the Urogenital System
Symposium on Urogenital Surgery
Traumatic Injuries of the Urogenital System
Dale E. Bjorling, D.V.M.*
While traumatized animals are frequently presented for treatment, the incidence of traumatic injuries of the urogenital system in small animal practice has not been determined. Kolata and Johnston found urinary tract injuries in 15 of 600 dogs involved in motor vehicle accidents. 25 It has been reported that more than 4 per cent of dogs with pelvic fractures have coexisting lesions of the urinary tract. 38 Selcer found a much higher incidence (39 per cent) of urinary tract injuries when she critically evaluated 100 consecutive dogs with traumatically induced pelvic fractures. 40 Three reports dealing with the diagnosis and incidence of intra-abdominal injuries following blunt and penetrating trauma indicated that when damage had occurred to the abdominal viscera, the urinary tract was involved in 31 per cent (13 of 42) of these animals. 5 • u. 26 At least one author suggests that injuries of the urinary tract are relatively common in dogs and cats. 22 The reproductive organs are injured much less frequently than those of the urinary tract. Diagnosis of urogenital system injuries is often delayed, resulting in a significant mortality rate. 7• 13 If the possibility of damage to the urogenital system is considered from the outset and the diagnosis pursued, the overall morbidity and mortality associated with urogenital system injuries may be reduced. Urogenital injury should be considered when fractures of the caudal ribs, vertebrae, or pelvis are seen on survey radiographs. 22 · 38 · 40 Penetrating wounds of the sublumbar region, caudal abdomen, and perineum may be associated with damage to underlying organs of the urogenital system. 5 • 45 Blunt trauma may result in significant disruption of the urogenital system while causing little apparent damage to more superficial struc' tures.14 Diagnosis and treatment of traumatic injuries of the urogenital system does not take precedence over treatment of shock, respiratory distress or ongoing hemorrhage. 33 Leakage of urine into the peritoneal cavity, retro*Assistant Professor, Department of Small Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, Georgia
Veterinary Clinics of North America: Small Animal Practice-Vol. 14, No. 1, January 1984
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peritoneal space, or pelvic and perineal tissues is not rapidly fatal. 7 • 30• 33 In humans, extravasation of sterile urine is relatively harmless for 24 to 36 hours. 30 Under experimental conditions, death occurred about three days after rupture of the bladder in dogs, and total nephrectomy in dogs results in death after three to six days. 7• 33
DIAGNOSIS OF UROGENITAL INJURIES The historical account of the type of trauma and time of occurrence help to establish an index of suspicion of urogenital system trauma. The owner may observe dysuria or signs relating to extravasation of urine. 7• 33 Delayed injury to the urogenital system can develop several weeks after the initial traumatic episode. 37 · Physical examination of the urogenital system is limited to palpation of the kidneys, bladder, and uterus, and examination of the external organs. The bladder or gravid uterus may be trapped through a tear in the abdominal wall (Fig. 1). Swelling in the sublumbar or perineal region may suggest rupture of the ureters or urethra. 13· 38 Distention of the bladder without passage of urine can result from disruption of the urethra. 15 Pooling of urine in the abdomen will usually lead to abdominal tenderness, elevated temperature, and vomiting, signs associated with peritonitis or uremia. 7 • 13 Unfortunately these signs are not specific for urinary tract trauma and their time of onset is variable. 7 The unreliability of physical examination in the diagnosis of intra-abdominal injury has been previously noted. 5 • 26 • 38 • 45 Likewise, the spontaneous passage of urine does not rule out the presence 'o f a ruptured bladder or partial laceration of the urethra. 7• 38 Passage of a urinary catheter may give misleading information about the degree of injury to the urinary tract. It is possible to pass a catheter into the bladder despite the presence of partial tears of the urethra. 29 • 38 Return of urine through the catheter is not diagnostically helpful as a small amount of urine often remains in the bladder after it has ruptured, or the catheter may be passed through a tear in the bladder wall and into a pool of urine in the abdominal cavity. 29 • 33 Rupture of the bladder may be diagnosed by inflating the bladder and listening for the sound of gas escaping through the defect in the bladder wall. 7 • 22 This does not rule out the possibility of a laceration of the proximal urethra. Carbon dioxide should be used to inflate the bladder since the instillation of air into the bladder has resulted in fatal air embolus. 1· 46 Passage of a urinary catheter may cause further damage to the urine. 29 If a urethral catheter is passed, it is advisable to use a soft catheter* and adequate lubrication to minimize'further trauma. If urethral injuries are suspected, a positive contrast urethrogram should be performed before passing a catheter into the bladder. 38 The presence of free urine in the abdominal cavity indicates disruption of the urinary tract. Abdominal paracentesis with a syringe and needle may retrieve fluid, but the use of a peritoneal dialysis cathetert has been found *Sovereign Feeding Tube and Urethral Catheter, Sherwood Medical Industries, Inc., St. Louis, Missouri. tTrocath, McGraw Laboratories, American Hospital Supply Corp., Norcross, Georgia.
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Figure 1. Traumatically induit hernia of the abdominal w I. Gravid uterus is passing th ough the defect in the abdominal wall (arrow).
to be more accurate in the detection of intra-abdominal fluid . 11 · 26 If fluid is not returned with insertion of the dialysis catheter, diagnostic peritoneal lavage should be performed using 20 ml of sterile saline per kilogram body weight. The technique for diagnostic peritoneal lavage in small animals has been previously described. 11 • 26 If the bladder is distended, it should be catheterized or drained by cystocentesis prior to insertion of the dialysis catheter to minimize the chance of penetrating the bladder with the catheter.U Unless the bladder wall is damaged, cystocentesis should not result in sufficient leakage of urine into the abdominal cavity to confuse the diagnosis. Abdominal paracentesis and diagnostic peritoneal lavage will not detect retroperitoneal injuries. 5 • 45 Hemorrhage or leakage of urine associated with injuries of the kidneys, ureters, and occasionally the bladder and urethra may be confined to the retroperitoneal space.37 • 40• 47
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To determine if fluid retrieved from the abdominal cavity contains urine, it must be compared with peripheral blood. 7 · 11 · 26 Five to six hours after experimental rupture of the bladder in dogs, the blood urea nitrogen rose but did not exceed normal limits. 7 • 41 The urea concentration of abdominal fluid was higher than that of blood. 33 Forty-five hours after bladder rupture, the urea concentration in abdominal fluid equaled the concentration in the blood. The creatinine concentration in abdominal fluid was more than twice that ofperipheral blood. The urea molecule is small and equilibrates with blood relatively rapidly across the peritoneal membrane, whereas the creatinine molecule is larger and is retained longer in the abdominal cavity. 43 When the concentration of creatinine in abdominal fluid or peritoneal lavage fluid exceeds that of peripheral blood, it may be assumed that urine is leaking into the abdomen. 11 Abnormal concentrations of urea, creatinine, or potassium in the peripheral blood of animals that have been traumatized may suggest disruption of the urinary tract but are not diagnostic. Other causes of azotemia, including long-standing renal disease, should be considered. Prerenal azotemia due to hypovolemia or dehydration may develop after injury. 33 If the animal continues to void urine, azotemia may not develop for a considerable time, despite extravasation of urine. 7 The packed cell volume will increase as the animal becomes dehydrated due to vomiting, reluctance to drink, and fluid accumulation in the abdomen. 7 • 33 Although metabolic acidosis is a common occurrence with azotemia, acidemia was not a consistent finding after experimental rupture of the bladder. Acidemia may not develop after rupture of the bladder owing to the number of hydrogen and chloride ions lost through vomiting. 7 Hematuria is commonly seen after trauma to the urinary tract but its presence does not indicate the location of the injury. 40 Hematuria may result from contusion without disruption of the urinary tract. 4° Conversely clear urine may be obtained from a ruptured bladder. 7 • 40 Radiography is often necessary to diagnose injuries to the urinary tract. 34 Even if damage to the tract is positively diagnosed by other means, appropriate radiographic studies should be done to select the proper course of treatment. 3 • 47 Surgical correction of damage to the urinary tract should not be attempted until the exact location and extent of injuries has been determined. Survey radiographs may suggest injury to the urinary tract but are infrequently diagnostic. 34 • 47 In one study, changes in the appearance of the retroperitoneal space were the most consistent survey radiographic findings associated with the injury. 40 Disruption of the ureters, bladder, and urethra all commonly resulted in increased density with mottling-or streaking of the retroperitoneal space (Fig. 2). 40 Displacement or asymmetry of the kidneys, loss of the renal shadow, reduction in size or absence of the bladder, or the presence of abdominal fluid on survey radiographs of traumatized animals are all indications for further evaluation of the urinary tract. 22 • 34 • 47 Detailed discussions of the technical aspects of evaluation of the urinary tract with contrast radiography are available. 15 · 16 · 34 Diagnosis of urethral injuries usually requires -positive contrast urethrography. 38 A negative contrast urogram does not have any advantage
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Figure 2. A, Survey abdominal radiograph taken after dog was hit by a car. The retroperitoneal space is increased in density and extends farther ventrally than normal (arrows). B, Excretory urogram shows that ureters are intact but contrast material is escaping from the proximal urethra. Extravasated urine and contrast material are confined to the retroperitoneal space.
over positive contrast studies and will not always identify the location of urethral tears. It should be emphasized again that the use of air as a negative contrast medium is a potentially dangerous practice. 1 Extravasation of dye positively identifies the presence of a defect in the urethral wall. 38 It has been shown experimentally that contrast media will not enter the bladder during urethrography if the urethra is completely transected. 38 Rupture of the bladder accompanied by transection of the urethra may not be diagnosed preoperatively. 29 The integrity of the bladder 'is best assessed by positive contrast cystography. 7 The bladder should be distended with contrast material to facilitate diagnosis of small defects in the bladder wall.33 Negative contrast studies may help to identify blood clots or other intraluminal objects, but
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in general are of limited value in the diagnosis of traumatic injuries of the urinary tract. If radiographic studies of the lower urinary tract have not identified the area of urinary leakage or if trauma to the kidneys and ureters is suspected, an excretory urogram should be performed. Excretory urography is required to diagnose injuries of the kidneys and ureters confined to the retroperitoneal space. The late phase of an excretory urogram may provide information about injuries of the bladder and urethra. 15• 16· 34 Since the intravenous injection of contrast media has been associated with bradycardia and hypotension/ 6 excretion of dye may be delayed in hypotensive animals and an unsatisfactory study may result. 47 Prolonged renal excretion of dye has caused renal damage in humans, and it has been recommended that excretory urography not be performed on dehydrated animals. 15 It may be advisable to delay excretory urography until the animal is resuscitated and rehydrated. Failure to observe opacification of a kidney during the nephrographic phase of an excretory urogram may be due to avulsion of a renal artery but can also result from renal aplasia. 15 Ideally, angiography should be used to evaluate the blood supply to the kidney. 22 An alternative to selective angiography is provided by "rapidly injecting a bolus of contrast material into a large vein and making two to three radiographs at five- or six-second intervals after the start of injection. "34 If nephrectomy is contemplated, it is essential to establish that the contralateral kidney has normal function. A general correlation has been observed between the radiographic quality of the excretory urogram and the excretory function of the kidney. 48 Unless the peritoneum has been disrupted, contrast material that is lost from the. kidney or ureter will accumulate in the retroperitoneal space. Severe parenchymal damage to the kidney may cause diffuse retention of contrast material within the renal capsule. 34 When the ureter has been damaged, the ureter proximal to the site of injury and the associated renal pelvis will usually be dilated. 6 • 33 Evaluation of the urinary tract should progress in an orderly manner (Fig. 3). The history and physical examination should indicate the next step to be taken. Fractures or abnormal findings on abdominal palpation should be pursued with radiographs. The nature and source of abdominal fluid should be determined by paracentesis and careful evaluation of the fluid obtained. Diagnostic peritoneal lavage will increase the chance of obtaining fluid and cells representative of those present in the abdomen. Continued malaise (depression, nausea, vomiting, anorexia) can be observed two to three days after urinary tract trauma. 7 • 33 The need for further evaluation of the urinary tract may be suggested by a complete blood count and serum chemistries and electrolytes. If urine is present in the abdominal cavity, the urethra and bladder should be examined with retrograde urethrography and cystography. Should contrast studies of the urethra and bladder fail to identify the source of urine entering the abdominal cavity, or if survey radiographs indicate the presence of retroperitoneal injuries, excretory urography should be performed. All of these diagnostic tests are not required for evaluation of the urinary tract in e~ery traumatized animal. However, thorough evaluation will increase the number of urinary tract
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THE UROGENITAL SYSTEM Observation
~Passes
Hematuria Alone
Easily• Obstruction __..Plain Radiograph)' " " / C o m p l e t e / Partial (Below)
Gently Catheterize
\
Hematuria/Dysuria
I
History Physical Examination
I1-----<"'-.. -'
Distended or Absent BlaQder/Inability to Urinate /Pel vic Practures/Retroper itoneal or Perineal Swelling/Uremia
I
Plain Radiography
~
~
\~ Abdominal
l \
Retroperitoneal swelling Lack of Renal Outline
Excretory
Urography~
\
Clin Path
Urethrography Cystography
.
.
Abdom1nal Flu1d
~
. Fluid~P~racent~sis
. D1:agnost1c Per1toneal
~Fluid
(CreatJ
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Fluid /(Creat]
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Other Diagnostic Tests *Passage of catheter does not rule out incomplete disruption of urethra.
Figure 3. Algorithm for diagnosis of urinary tract injuries. The diagnostic work-up should end when the clinician is satisfied that the urinary tract is intact. The exact location of the injury should be identified before surgery is performed.
injuries that are detected. Surgical exploration without adequate preoperative examination can be frustrating and does not insure that the function and integrity of the urinary tract has been satisfactorily assessed. EMERGENCY MANAGEMENT OF UROGENITAL INJURIES
Traumatic injuries of the urogenital system that constitute true emergencies are limited to those conditions resulting in ongoing hemorrhage or the inability to void urine. Emergency therapy should be directed at controlling hemorrhage and providing a pathway for the discharge ofurine. Injuries to the urogenital system should be diagnosed as quickly as possible, but prolonged anesthesia for the surgical repair of urogenital system lesions should be avoided if the animal is uremic or unstable. Uremic animals are sensitive to the effects of most anesthetics, analgesics, and ~edatives, and the dosages of these should be decreased. 4 • 49 Unless absolutely necessary, it is preferable to treat the animal for shock and establish diuresis prior to administering depressive drugs. Diuresis may be achieved even when urine is leaking into the abdomen. Urine will usually continue to accumulate in the bladder after it has been ruptured. 7 A urethral catheter will keep the bladder decompressed, but urine may still enter the peritoneal cavity. A catheter that is inadvertently passed through a defect in the urethra or bladder wall may drain some
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Figure 4. The end of the urethral catheter should be drawn back into the bladder. The combined drainage of the urethral catheter in the bladder and the dialysis catheter in the abdominal cavity allow diuresis despite the presence of a ruptured bladder.
urine from the abdomen. A simple intra-abdominal catheter does not remove fluid from the abdomen as effectively as a dialysis catheter (Fig. 4). 39
Commercially available dialysis catheters may be placed in a closed manner by inserting the catheter with its trocar in place into the abdomen through a stab wound in the skin. An alternative technique is to make a small incision in the linea alba and insert the catheter through the incision. This technique decreases the amount of hemorrhage caused by insertion of the catheter and decreases the risk of penetrating underlying viscera. Unless scars from previous abdominal surgery are present, the catheter should be inserted through the midline 2 to 4 em caudal to the umbilicus. As the catheter is being placed, the tip should be directed caudally. Once urine outflow has been established, diuresis may be initiated. Intravenous fluids should be given at a rate sufficient to correct dehydration and produce a urine flow of 3 to 6 ml per kg per hr. Dehydration should be corrected over the first two to three hours of fluid administration. Isotonic solutions may initially be given at a rate of 20 to 40 ml per kg per hr to produce diuresis. Fluid input should be adjusted with respect to urine outflow to maintain diuresis but avoid overhydration. If obstruction or disruption of the lower urinary tract prevents passage of a urethral catheter, the bladder may be kept temporarily decompressed by any of three methods: cystocentesis, a cystostomy catheterization, or marsupialization of the bladder. 3· 27 Cystocentesis is the preferred method for temporary decompression since it takes less time and does not require anesthesia or surgery. However, over a period of days multiple punctures of the bladder may be necessary. While this rarely causes problems with a normal bladder, these puncture sites may not seal properly if the bladder wall is diseased or distended. Marsupialization of the bladder or placement of a cystostomy catheter both require a brief surgical procedur.e and increase the potential of urinary tract infection. A cystostomy catheter is preferable to marsupialization of the bladder because a second surgical procedure is not needed to remove the catheter. Also, contamination of the urinary tract is not controllable during marsupialization of the bladder. A cystostomy catheter may also be left in place following urethral or bladder surgery to insure drainage of urine (Fig. 5). 38 A small (8 Fr. or smaller) Foley catheter is u~ed as a cystostomy catheter. The catheter should be drawn through a stab wound in the abdominal wall lateral to the midline incision. Two retention sutures are
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Figure 5. Cystostomy using a Foley catheter. The omentum may be draped or tacked around the point of entry of the catheter into the bladder to help prevent leakage of urine around the catheter.
placed to hold the bladder near the abdominal wall. The catheter is placed through the center of a pursestring suture on the cranioventral aspect of the bladder. The pursestring suture is tied and may be used to secure omentum around the puncture site in the bladder wall. The bulb of the catheter should be inflated with sterile saline. The abdominal wound is closed, and the catheter is sutured to the skin. The catheter is then attached to a closed drainage system. These catheters have been removed percutaneously as early as three days after placement without evidence of urine leakage. Emergency surgery may be needed to control hemorrhage from the urogenital system. The patient's blood volume should be maintained by intravenous administration of balanced salt solution, whole blood, or plasma. The use of whole blood or plasma should be considered when the packed cell volume and plasma total solids drop below 20 per cent and 3.5 gm per 100 ml, respectively. 18 TREATMENT OF UROGENITAL INJURIES Kidneys Renal injuries, classified as contusions, lacerations, severe fractures, and pedicle injuries, 28 are usually diagnosed by contrast radiography or at exploratory laparotomy. Unless it can be clearly demonstrated that they are interfering with renal function, contusions of the kidneys should be left undisturbed. 2• 20 Minor lacerations of the capsule and parenchyma may usually be closed with sutures to control hemorrhage, but severe fractures of the parenchyma may necessitate partial or total nephrectomy. 2• 20 Exploration of the perirenal retroperitoneal space and examination of the kidneys are facilitated by atraumatic occlusion of the renal vasculature. 2• 20 Severe injuries confined to a pole of the kidney may be treated by partial nephrectomy. Damaged parenchyma is removed, and the vessels supplying this area are ligated. Exposed renal parenchyma is covered with omentum and secured with mattress sutures through the renal parenchyma (Fig. 6). 4 Generalized crushing of the kidney or damage to the vascular pedicle may necessitate nephrectomy. Preservation of a normally functioning kidney after severe injury to the pedicle is rare. 28 Renal vascular repair should be
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Figure 6. Partial nephrectomy. After the damaged portion of the kidney has been debrided, the cut surface is covered by tacking omentum to the capsule. (From Kolata, R. J.: Abdominal trauma. Compend. Contin. Ed., 1:445-453, 1979; with permission .)
approached with caution and must be performed within two hours of injury to prevent ischemic necrosis of the kidney. 2 Ureter
The ureter in the dog is small and the difficulty of its repair has been previously noted. 9 At surgery, injuries of the ureter are best located by retrograde catheterization of the ureters following a ventral cystotomy. 10 Flushing sterile saline through the ureters will usually demonstrate a defect. Avulsion of the ureter from the kidney may be treated by reimplantation of the ureter in the renal pelvis. This is extremely difficult in the dog and cat when the ureter and renal pelvis are not dilated. Traumatic injuries that do not leave a satisfactory length of healthy ureter attached to the kidney for anastomosis may necessitate nephrectomy. It has been stressed that a strip of ureter bridging a defect should be preserved to promote healing. 8 · 12 However, adequate debridement usually creates a complete gap in the ureter. 8 The blood supply of the ureter is longitudinal, being derived cranially from the renal artery and caudally from the urogenital artery. The ends of the ureter should not be stripped of their blood supply during debridement. The kidney and its blood supply may be mobilized and drawn caudally to decrease tension on the site of anastomosis. Spatulation of the ends of the ureter by small longitudinal incisions to increase the diameter of the suture line is recommended (Fig. 7).9 A tensionless , watertight closure of the ureter should be performed over a catheter using small gauge (5-0 to 6--0) absorbable suture. 8 · 12 Absorbable suture material is recommended for use in the urinary tract to decrease the potential for calculi formation on implanted, nonabsorbable suture. 31 • 52 While either chromic gut or synthetic absorbable sutures are satisfactory for use in the urinary tract, synthetic absorbable products may
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Figure 7. The debrided ends of a damaged ureter are spatulated by making small longitudinal incisions in the ends of the ureter. This increases luminal diameter when the ureteral anastomosis is completed.
be preferable as they stimulate less inflammation during their degradation.31· 38 It has been suggested that catheters left in the ureter during healing lead to , infection and fibrosis. 8 Intraluminal catheters cause reversible inflammatory changes in the wall of the ureter and may lead to transient ureteral obstruction after their removal. A ureteral catheter that is too tight may cause increased fibrosis .51 However, diversion of urine from the healing area of the ureter appears to enhance healing, 19· 32 and routine stenting of the ureter following repair is recommended. 35 Silas tic and rubber tubing appear to be superior to polyethylene tubing as ureteral stents. 35 The ureteral catheter may be used to drain the kidney and may be externalized through the urethra or across the bladder wall through the abdomen. Injuries to the distal third of the ureter are best treated by reimplantation of the ureter into the bladder (ureteroneocystostomy). The ureter should be placed through a tunnel in the bladder wall approximately five times the ureteral diameter in length. 44 This is to prevent reflux of urine from the bladder into the ureter. The end of the ureter is spatulated and sutured to the bladder mucosa. Excessive tension on the site of reimplantation is avoided by freeing the associated kidney and drawing it caudally or by fixing the bladder in a more cranial position (psoas-hitch procedure). To displace the bladder cranially, the ligaments of the bladder are partially incised, taking care to preserve the blood supply. After the ureter has been reimplanted, the bladder is pulled cranially on the side of the injured ureter and tacked to the fascia of the sublumbar musculature with absorbable sutures. 50
Bladder Lacerations of the bladder wall should be debrided and closed. If the tear is located near a ureteral orifice, the ureter should be identified and
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catheterized to prevent inadvertent ureteral obstruction or injury. The bladder may have to be distended with sterile saline to identify defects. in the bladder wall. The bladder should be carefully examined, as multiple lacerations may result from blunt or penetrating trauma. The bladder is kept decompressed following surgery by allowing frequent urination or with an indwelling catheter. Urethra Traumatic injuries of the urethra occur almost exclusively in the male dog and cat. 38• 40 The urethra of the female may be damaged during catheterization. The urethra, like the ureter, will regenerate over a catheter if a viable strip of tissue bridges a defect. 52 This method of treatment should generally be reserved for very small lacerations or punctures of the urethra. Large defects may require the presence of a catheter for three to four weeks to completely heal. 52 Most traumatic lacerations of the urethra should be treated by debridement and primary repair using absorbable suture (30 or 4-0) in a simple interrupted pattern. 40 Damage to prostatic tissue overlying the urethra may make primary repair of the prostatic urethra difficult. Partial or total removal of the prostate gland may be required to allow repair of the prostatic urethra. Repair of the urethra should not be attempted without adequate exposure. Exploration of the pelvic urethra may require a trans-symphyseal approach33 or reflection of a portion of the pubis. 21 Diversion of urine through either a urethral or a cystostomy catheter, or both, is recommended during healing of urethral defects. 3 • 29 • 38 Urethral stricture and urinary incontinence are frequent complications following traumatic urethral injuries. 38• 53 A catheter that distends the urethra will enhance stricture formation. 52 Urinary incontinence can result from primary damage to the innervation and blood supply of the urethral sphincter or iatrogenic damage to these structures during surgical intervention. Some degree of urinary incontinence was observed in five of six dogs that were evaluated nine months or more after prostatectomy. 17 Primary repair of the urethra should not be attempted if the defect in the urethra is too large to close without tension on the suture line. Large segmental defects in the urethras of male dogs have been treated by extrapelvic anastomosis of the bladder to the penile urethra24 and by antepubic urethrostomy. 53 Extrapelvic anastomosis of the bladder to the urethra is done by first incising the urethra near the neck of the bladder. The bulb of the penis (formerly called the urethral bulb), the penile urethra, and the bulbospongiosus and retractor penile muscles are severed. The distal cut end of the bulb of the penis is brought cranially through the abdominal incision, and the penile urethra is anastomosed to the urethra near the neck of the bladder (Fig. 8). If intact, the animal should be castrated. Antepubic urethrostomy may be performed in male or female animals. The maximum amount of viable intra-abdominal and pelvic urethra should be identified, dissected free, and preserved to maintain urinary continence and provide a sufficient length of urethra to lead from the bladder to the abdominal wall. It may be necessary to separate the pelvic symphysis. In males, the urethrostomy opening will be located 2 to 3 em lateral to the
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Figure 8. Extrapelvic anastomosis of the bladder to the penile urethra. The bulbous portion of the urethra is anastomosed to the neck of the bladder within the abdomen. (Adapted ·from Knecht, C. D., and Slusher, R.: Extrapelvic anastomosis of the bladder and penile urethra in a dog. J. Am. Anim. Hosp. Assoc., 149:1729-1734, 1966.
prepuce, while in females the stoma will be on or near the midline. Care should be taken when performing the urethrostomy to avoid bending the urethra too sharply, resulting in obstruction of the urethra. The severed end of the proximal urethra is spatulated with a small incision on its ventral surface, and the urethra is secured to the skin with nonabsorbable sutures in an interrupted pattern (Fig. 9). Male Reproductive Tract
Laceration of the tip of the penis or external urethral meatus should be carefully debrided and sutured with small gauge (4-0) nonabsorbable suture. A tourniquet around the proximal penis will decrease the amount of blood in the field and improve the precision with which sutures are placed. 38
Figure 9. Antepubic urethrostomy. The proximal urethra is brought through the midline (female) or in a paramedian location (male), and the urethra is sutured to the skin. (Adapted from Yoshioka, M. M., and Carb, A. : Antepubic urethrostomy in the dog. J. Am. Anim. Hosp. Assoc., 18:290-294, 1982.)
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Fracture of the os penis may result in occlusion or disruption of the penile urethra. If a catheter can be passed and the fragments are well aligned, the fracture may heal satisfactorily without further treatment. If the fragments are badly displaced or shattered, surgery can be performed to realign the fragments or remove the os penis. 2 A prescrotal urethrotomy will allow catheterization of the bladder if a urethral catheter will not pass through the penile urethra. Extensive damage to the penile urethra or subsequent stricture formation may necessitate the creation of a permanent urethrostomy proximal to the site of injury. Minor lacerations of the scrotum may usually be closed primarily with or without placement of a drain. It is difficult to satisfactorily treat established scrotal or testicular infections with antibiotics and drainage. Castration and scrotal ablation is often the best method of treatment for infected or badly contaminated lacerations and puncture wounds of the scrotum.
Female Reproductive Tract The female reproductive tract is rarely traumatized. Lacerations of the external genitalia may be sutured. An episiotomy should be performed when appropriate to increase exposure of the vaginal vault and urethral orifice. Catheterization of the urethra prior to repair of injuries of the vaginal floor will prevent accidental occlusion of the urethra. Antepubic urethrostomy may also be performed in the female dog following injury to the urethra or removal of the vagina. 53 The uterus is most likely to be traumatically injured when gravid. Possible sequelae to uterine trauma include metritis, peritonitis, abortion, fetal death, and hemorrhage. Disruption of the uterine wall does not inevitably lead to fetal death or pyometra, and minor lacerations may be sutured. 42 The owner should be warned of the possible adverse effects of traumatic injuries on the fetuses. Hemorrhage or loss of blood supply and extensive injury to the uterus may necessitate ovariohysterectomy.
REFERENCES 1. Ackerman, N., Wingfeld, W. E., and Corley, E. A. : Fatal air embolism associated with pneumourethrography and pneumocystography in a dog. J. Am. Vet. Med. Assoc. , 160:1616-1618, 1972. 2. Archibald, J., Holt, J. C., and Sokolovsky, V.: Urogenital injuries. In Catcott, E. J. (ed.): Management of Trauma in Dogs and Cats. Santa Barbara, California, American Veterinary Publications, Inc., 1981. 3. Aultman, S. H., and Betts, C. W.: An unusual case of a prostatic cy'st. Utilization of a suprapubic catheter. J. Am. Anim . Hosp. Assoc., 14:638-644, 1978. 4. Bennett, W. M., Singer, I., and Coggins, C. J.: A guide to drug therapy in renal failure. J.A. M.A., 230:1533-1544, 1974. 5. Bjorling, D. E., Crowe, D. T., Jr., Kolata, R. J., et al.: Penetrating abdominal wounds in dogs and cats. J. Am. Anim. Hosp. Assoc,, 18:742-748, 1982. 6. Brodsky, S. L., Zinskind, P. D. , Dure-Smith, P. , et al.: Effects of crush and devascularizing injuries to the proximal ureter: An experimental study. Invest. Urol., 14:361-365, 1977. 7. Burrows, C. F., Bovee, K. C.: Metabolic changes due to experimentally induced rupture of the canine urinary bladder. Am. J. Vet. Res., 35:1083-1088, 1974.
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8. Carlton, C . E.: Upper urinary tract trauma. In Glenn, J. F. (ed.): Urologic Surgery. Edition 2. Hagerstown, Maryland, Harper & Row, 1975. 9. Chomchark, C., Eckert, C.: Repair of the ureter severed at operation. Ann. Surg., 177:748-754, 1973. 10. Crane, S. W. : Evaluation and management of abdominal trauma in the dog and cat. VET. CLIN. NORTH AM., SMALL ANIM. CLIN., 10:655-689, 1980. 11. Crowe, D. T., Jr., and Crane, S. W.: Diagnostic paracentesis and lavage in the evaluation of abdominal injuries in dogs and cats: Clinical and experimental investigations. J. Am. Vet. Med. Assoc., 168:700-705, 1976. 12. Davis, D. M. , Strong, G. H ., and Drake, W. M.: Intubated ureterotomy: Experimental work and clinical results. J. Urol., 59:851-862, 1948. 13. DeHoff, W. D., Greene, R. W. , and Greiner, T. P.: Surgical management of abdominal emergencies. VET. CLIN. NORTH AM. , 2:301-330, 1979. 14. Dingwall, J. S. : Surgical management of abdominal trauma. J. Am. Vet. Med. Assoc., 159:1406-1413, 1971. 15. Feeney, D. A., Barber, D. L., and Osborne, C . A.: Advances in canine excretory urography. In Proceedings of the Thirtieth Gaines Veterinary Symposium . White Plains, New York, Gaines Dog Research Center, 1981. 16. Feeney, D . A., Barber, D. L. , Joh.iston, G. R., et al.: The excretory urogram: Parts I and II. Com pend. Con tin. Ed. , 4:233-243, 321-329, 1982. 17. Hardie, E. M., Rawlings, C. A., and Barsanti, J. A.: Complications of prostatic surgery. J. Am. Anim. Hosp. Assoc., 1983, in press. 18. Haskins, S. C.: Blood volume support. VET. CLIN. NORTH AM .. 6:265-275, 1976. 19. Hinman, F., and Oppenheimer, R. : Urethral regeneration : VI. Delayed urinary flow in the healing of unsplinted urethral defects. J. Urol. , 78:138-144, 1957. 20. Holcroft, J. W., Trunkey, D. D., Minasi, M., et al.: Renal trauma and retroperitoneal hematomas: Indications for exploration. J. Trauma, 15:1045-1052, 1975. 21. Howard, D . R.: Surgical approach to the canine prostate. J. Am. Vet. Med. Assoc., 155:2026-2031, 1967. 22. Kleine, L. J., and Thornton, G. W. : Radiographic diagnosis of urinary tract trauma. J. Am. Anim . Hosp. Assoc., 7:318-327, 1971. 23. Knecht, C. D. : A symphyseal approach to pelvic surgery in the dog. J. Am. Vet. Med. Assoc., 149:1729-1734, 1966. 24. Knecht, C. D., and Slusher, R.: Extrapelvic anastomosis of the bladder and penile urethra in a dog. J. Am. Anim. Hosp. Assoc., 6:247-251, 1970. 25. Kolata, R. J., and Johnston, D. E.: Motor vehicle accidents in urban dogs: A study of 600 cases. J. Am. Vet. Med. Assoc., 167:938-941, 1975. 26. Kolata, R. J. : Diagnostic abdominal paracentesis and lavage: Experimental and clinical evaluation in the dog. J. Am. Vet. Med. Assoc., 168:697-699, 1976. 27. Mcintire, J. W., and Waugh, S. L.: Marsupialization of the urinary bladder for a urethral laceration. Feline Pract., 11:36-38, 1981. 28. Mendez, R.: Renal trauma. J. Urol. , 118:698-703, 1977. 29. Mitchell, J. P.: Injuries to the urethra. Br. J. Urol., 40:649-670, 1968. 30. Mitchell, J. P.: Trauma to the urinary tract. l'•i.'Engl. J. Med., 288:90-92, 1973. 31. Morrow, F. A. , Kogan, S. J., Freed, S. W., et al.: In vivo comparison of polyglycolic acid, chronic catgut and silk in tissue of the genitourinary tract: An experimental study of tissue retrieval and calculogenesis. J. Urol., 112:655-658, 1974. 32. Oppenheimer, R. 0. F., and Hinman, F. : The effect of urinary flow on ureteral regeneration in the absence of a splint. Surg. Gynecol. Obstet. , 103:416-422, 1956. 33. Osborne, C. A., and Finco, D. R.: Urinary tract emergencies and renal care following trauma. VET. CLIN. NORTH AM., 9:259-191, 1979. 34. Pechman, R. D.: Urinary trauma in dogs and cats: A review. J. Am. Anim. Hosp. Assoc., 18:33-40, 1982. 35. Pitts, J. C., and Peterson, N. E.: Penetrating injuries of the ureter. J. Trauma, 21:978982, 1981. 36. Raney, A. M. : Radiographic findings immediately after urethral rupture: An experimental study and case reports. J. Urol., 116:581-582, 1976. 37. Rawlings, C. A.: Extraperitoneal urinary bladder rupture and UJ;,inary fistula in a dog. J. Am. Vet. Med. Assoc., 115:123-128, 1969.
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38. Rawlings, C. A., and Wingfield, W. E.: Urethral reconstruction in dogs and cats. J. Am. Anim. Hosp. Assoc., 12:850-860, 1976. 39. Root, H . D., Hauter, C. W., McKinley, C . R., et al.: Diagnostic peritoneal lavage. Surgery, 57:633-637, 1965. 40. Selcer, B. A.: Urinary tract trauma associated with pelvic trauma. J. Am. Anim. Hosp. Assoc., 18:75--793, 1982. 41. Shah, P. M., Kin, K.-H ., Ramirez-Schenb, G., et al.: Elevated blood urea nitrogen: An aid to the diagnosis of intraperitoneal rupture of the bladder. J. Urol., 122:741-743, 1979. • 42. Smith, K. W. : Female genital system. In Archibald, J. (ed.): Canine Surgery. Edition 2. Santa Barbara, California, American Veterinary Publications, Inc., 1974. 43. Sullivan, M. J., Lackner, L. U. , and Barowsky, L. H. W. : Intraperitoneal extravasation ofurine. }.A.M.A., 221:491-492, 1972. 44. Tarvin, G. B.: Surgical treatment of ectopic ureters. VET. CLIN. NORTH AM.: SMALL ANIM. PRACT., 9:277-284, 1979. , 45. Thai, E . R.: Evaluation of peritoneal lavage and local exploration in lower chest and abdominal stab wounds. J. Trauma, 17:642-648, 1977. 46. Thayer, G. W., Carrig, C. B., and Evans, A. T.: Fatal venous air embolism associated with pneumocystography in a cat. J. Am. Vet. Med. Assoc., 176:643-645, 1980. 47. Thornhill, J. A. , and Cechner, P. E.: Traumatic injuries to the kidneys, ureter, bladder and urethra. VET. CLIN. NORTH AM.: SMALL ANIM. PRACT., 11:157-170, 1981. 48. Thrall, D. E., and Finco, D. R. : Canine excretory urography: Is quality a function of BUN? J. Am. Anim. Hosp. Assoc., 12:446-450, 1976. 49. Trim, C . : Anesthesia and the kidney. Compend. Contin. Ed., 11:843-847, 1979. 50. Warwick, R. T., and Worth, P. H. L.: The psoas-hitch procedure for the replacement of the lower third of the ureter. Br. J. Urol., 4:701-709, 1969. 51. Weaver, R. G. : Basic surgical principles of ureteral repair. Surg. Gynecol. Obstet., 110:594-600, 1960. . 52. Weaver, R. G., and Schultz, J. W.: Experimental and clinical studies of urethral regeneration. Surg. Gynecol. Obstet., 115:729-736, 1962. 53. Yoshioka, M. M., and Carb, A. : Antepubic urethrostomy in the dog. J. Am. Anim. Hosp. Assoc., 18:290-294, 1982. Department of Small Animal Medicine College of Veterinary Medicine University of Georgia Athens, Georgia 30602
Traumatic Injuries of the Urogenital System
Dale E. Bjorling, D.V.M.*
While traumatized animals are frequently presented for treatment, the incidence of traumatic injuries of the urogenital system in small animal practice has not been determined. Kolata and Johnston found urinary tract injuries in 15 of 600 dogs involved in motor vehicle accidents. 25 It has been reported that more than 4 per cent of dogs with pelvic fractures have coexisting lesions of the urinary tract. 38 Selcer found a much higher incidence (39 per cent) of urinary tract injuries when she critically evaluated 100 consecutive dogs with traumatically induced pelvic fractures. 40 Three reports dealing with the diagnosis and incidence of intra-abdominal injuries following blunt and penetrating trauma indicated that when damage had occurred to the abdominal viscera, the urinary tract was involved in 31 per cent (13 of 42) of these animals. 5 • u. 26 At least one author suggests that injuries of the urinary tract are relatively common in dogs and cats. 22 The reproductive organs are injured much less frequently than those of the urinary tract. Diagnosis of urogenital system injuries is often delayed, resulting in a significant mortality rate. 7• 13 If the possibility of damage to the urogenital system is considered from the outset and the diagnosis pursued, the overall morbidity and mortality associated with urogenital system injuries may be reduced. Urogenital injury should be considered when fractures of the caudal ribs, vertebrae, or pelvis are seen on survey radiographs. 22 · 38 · 40 Penetrating wounds of the sublumbar region, caudal abdomen, and perineum may be associated with damage to underlying organs of the urogenital system. 5 • 45 Blunt trauma may result in significant disruption of the urogenital system while causing little apparent damage to more superficial struc' tures.14 Diagnosis and treatment of traumatic injuries of the urogenital system does not take precedence over treatment of shock, respiratory distress or ongoing hemorrhage. 33 Leakage of urine into the peritoneal cavity, retro*Assistant Professor, Department of Small Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, Georgia
Veterinary Clinics of North America: Small Animal Practice-Vol. 14, No. 1, January 1984
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peritoneal space, or pelvic and perineal tissues is not rapidly fatal. 7 • 30• 33 In humans, extravasation of sterile urine is relatively harmless for 24 to 36 hours. 30 Under experimental conditions, death occurred about three days after rupture of the bladder in dogs, and total nephrectomy in dogs results in death after three to six days. 7• 33
DIAGNOSIS OF UROGENITAL INJURIES The historical account of the type of trauma and time of occurrence help to establish an index of suspicion of urogenital system trauma. The owner may observe dysuria or signs relating to extravasation of urine. 7• 33 Delayed injury to the urogenital system can develop several weeks after the initial traumatic episode. 37 · Physical examination of the urogenital system is limited to palpation of the kidneys, bladder, and uterus, and examination of the external organs. The bladder or gravid uterus may be trapped through a tear in the abdominal wall (Fig. 1). Swelling in the sublumbar or perineal region may suggest rupture of the ureters or urethra. 13· 38 Distention of the bladder without passage of urine can result from disruption of the urethra. 15 Pooling of urine in the abdomen will usually lead to abdominal tenderness, elevated temperature, and vomiting, signs associated with peritonitis or uremia. 7 • 13 Unfortunately these signs are not specific for urinary tract trauma and their time of onset is variable. 7 The unreliability of physical examination in the diagnosis of intra-abdominal injury has been previously noted. 5 • 26 • 38 • 45 Likewise, the spontaneous passage of urine does not rule out the presence 'o f a ruptured bladder or partial laceration of the urethra. 7• 38 Passage of a urinary catheter may give misleading information about the degree of injury to the urinary tract. It is possible to pass a catheter into the bladder despite the presence of partial tears of the urethra. 29 • 38 Return of urine through the catheter is not diagnostically helpful as a small amount of urine often remains in the bladder after it has ruptured, or the catheter may be passed through a tear in the bladder wall and into a pool of urine in the abdominal cavity. 29 • 33 Rupture of the bladder may be diagnosed by inflating the bladder and listening for the sound of gas escaping through the defect in the bladder wall. 7 • 22 This does not rule out the possibility of a laceration of the proximal urethra. Carbon dioxide should be used to inflate the bladder since the instillation of air into the bladder has resulted in fatal air embolus. 1· 46 Passage of a urinary catheter may cause further damage to the urine. 29 If a urethral catheter is passed, it is advisable to use a soft catheter* and adequate lubrication to minimize'further trauma. If urethral injuries are suspected, a positive contrast urethrogram should be performed before passing a catheter into the bladder. 38 The presence of free urine in the abdominal cavity indicates disruption of the urinary tract. Abdominal paracentesis with a syringe and needle may retrieve fluid, but the use of a peritoneal dialysis cathetert has been found *Sovereign Feeding Tube and Urethral Catheter, Sherwood Medical Industries, Inc., St. Louis, Missouri. tTrocath, McGraw Laboratories, American Hospital Supply Corp., Norcross, Georgia.
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Figure 1. Traumatically induit hernia of the abdominal w I. Gravid uterus is passing th ough the defect in the abdominal wall (arrow).
to be more accurate in the detection of intra-abdominal fluid . 11 · 26 If fluid is not returned with insertion of the dialysis catheter, diagnostic peritoneal lavage should be performed using 20 ml of sterile saline per kilogram body weight. The technique for diagnostic peritoneal lavage in small animals has been previously described. 11 • 26 If the bladder is distended, it should be catheterized or drained by cystocentesis prior to insertion of the dialysis catheter to minimize the chance of penetrating the bladder with the catheter.U Unless the bladder wall is damaged, cystocentesis should not result in sufficient leakage of urine into the abdominal cavity to confuse the diagnosis. Abdominal paracentesis and diagnostic peritoneal lavage will not detect retroperitoneal injuries. 5 • 45 Hemorrhage or leakage of urine associated with injuries of the kidneys, ureters, and occasionally the bladder and urethra may be confined to the retroperitoneal space.37 • 40• 47
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To determine if fluid retrieved from the abdominal cavity contains urine, it must be compared with peripheral blood. 7 · 11 · 26 Five to six hours after experimental rupture of the bladder in dogs, the blood urea nitrogen rose but did not exceed normal limits. 7 • 41 The urea concentration of abdominal fluid was higher than that of blood. 33 Forty-five hours after bladder rupture, the urea concentration in abdominal fluid equaled the concentration in the blood. The creatinine concentration in abdominal fluid was more than twice that ofperipheral blood. The urea molecule is small and equilibrates with blood relatively rapidly across the peritoneal membrane, whereas the creatinine molecule is larger and is retained longer in the abdominal cavity. 43 When the concentration of creatinine in abdominal fluid or peritoneal lavage fluid exceeds that of peripheral blood, it may be assumed that urine is leaking into the abdomen. 11 Abnormal concentrations of urea, creatinine, or potassium in the peripheral blood of animals that have been traumatized may suggest disruption of the urinary tract but are not diagnostic. Other causes of azotemia, including long-standing renal disease, should be considered. Prerenal azotemia due to hypovolemia or dehydration may develop after injury. 33 If the animal continues to void urine, azotemia may not develop for a considerable time, despite extravasation of urine. 7 The packed cell volume will increase as the animal becomes dehydrated due to vomiting, reluctance to drink, and fluid accumulation in the abdomen. 7 • 33 Although metabolic acidosis is a common occurrence with azotemia, acidemia was not a consistent finding after experimental rupture of the bladder. Acidemia may not develop after rupture of the bladder owing to the number of hydrogen and chloride ions lost through vomiting. 7 Hematuria is commonly seen after trauma to the urinary tract but its presence does not indicate the location of the injury. 40 Hematuria may result from contusion without disruption of the urinary tract. 4° Conversely clear urine may be obtained from a ruptured bladder. 7 • 40 Radiography is often necessary to diagnose injuries to the urinary tract. 34 Even if damage to the tract is positively diagnosed by other means, appropriate radiographic studies should be done to select the proper course of treatment. 3 • 47 Surgical correction of damage to the urinary tract should not be attempted until the exact location and extent of injuries has been determined. Survey radiographs may suggest injury to the urinary tract but are infrequently diagnostic. 34 • 47 In one study, changes in the appearance of the retroperitoneal space were the most consistent survey radiographic findings associated with the injury. 40 Disruption of the ureters, bladder, and urethra all commonly resulted in increased density with mottling-or streaking of the retroperitoneal space (Fig. 2). 40 Displacement or asymmetry of the kidneys, loss of the renal shadow, reduction in size or absence of the bladder, or the presence of abdominal fluid on survey radiographs of traumatized animals are all indications for further evaluation of the urinary tract. 22 • 34 • 47 Detailed discussions of the technical aspects of evaluation of the urinary tract with contrast radiography are available. 15 · 16 · 34 Diagnosis of urethral injuries usually requires -positive contrast urethrography. 38 A negative contrast urogram does not have any advantage
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Figure 2. A, Survey abdominal radiograph taken after dog was hit by a car. The retroperitoneal space is increased in density and extends farther ventrally than normal (arrows). B, Excretory urogram shows that ureters are intact but contrast material is escaping from the proximal urethra. Extravasated urine and contrast material are confined to the retroperitoneal space.
over positive contrast studies and will not always identify the location of urethral tears. It should be emphasized again that the use of air as a negative contrast medium is a potentially dangerous practice. 1 Extravasation of dye positively identifies the presence of a defect in the urethral wall. 38 It has been shown experimentally that contrast media will not enter the bladder during urethrography if the urethra is completely transected. 38 Rupture of the bladder accompanied by transection of the urethra may not be diagnosed preoperatively. 29 The integrity of the bladder 'is best assessed by positive contrast cystography. 7 The bladder should be distended with contrast material to facilitate diagnosis of small defects in the bladder wall.33 Negative contrast studies may help to identify blood clots or other intraluminal objects, but
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in general are of limited value in the diagnosis of traumatic injuries of the urinary tract. If radiographic studies of the lower urinary tract have not identified the area of urinary leakage or if trauma to the kidneys and ureters is suspected, an excretory urogram should be performed. Excretory urography is required to diagnose injuries of the kidneys and ureters confined to the retroperitoneal space. The late phase of an excretory urogram may provide information about injuries of the bladder and urethra. 15• 16· 34 Since the intravenous injection of contrast media has been associated with bradycardia and hypotension/ 6 excretion of dye may be delayed in hypotensive animals and an unsatisfactory study may result. 47 Prolonged renal excretion of dye has caused renal damage in humans, and it has been recommended that excretory urography not be performed on dehydrated animals. 15 It may be advisable to delay excretory urography until the animal is resuscitated and rehydrated. Failure to observe opacification of a kidney during the nephrographic phase of an excretory urogram may be due to avulsion of a renal artery but can also result from renal aplasia. 15 Ideally, angiography should be used to evaluate the blood supply to the kidney. 22 An alternative to selective angiography is provided by "rapidly injecting a bolus of contrast material into a large vein and making two to three radiographs at five- or six-second intervals after the start of injection. "34 If nephrectomy is contemplated, it is essential to establish that the contralateral kidney has normal function. A general correlation has been observed between the radiographic quality of the excretory urogram and the excretory function of the kidney. 48 Unless the peritoneum has been disrupted, contrast material that is lost from the. kidney or ureter will accumulate in the retroperitoneal space. Severe parenchymal damage to the kidney may cause diffuse retention of contrast material within the renal capsule. 34 When the ureter has been damaged, the ureter proximal to the site of injury and the associated renal pelvis will usually be dilated. 6 • 33 Evaluation of the urinary tract should progress in an orderly manner (Fig. 3). The history and physical examination should indicate the next step to be taken. Fractures or abnormal findings on abdominal palpation should be pursued with radiographs. The nature and source of abdominal fluid should be determined by paracentesis and careful evaluation of the fluid obtained. Diagnostic peritoneal lavage will increase the chance of obtaining fluid and cells representative of those present in the abdomen. Continued malaise (depression, nausea, vomiting, anorexia) can be observed two to three days after urinary tract trauma. 7 • 33 The need for further evaluation of the urinary tract may be suggested by a complete blood count and serum chemistries and electrolytes. If urine is present in the abdominal cavity, the urethra and bladder should be examined with retrograde urethrography and cystography. Should contrast studies of the urethra and bladder fail to identify the source of urine entering the abdominal cavity, or if survey radiographs indicate the presence of retroperitoneal injuries, excretory urography should be performed. All of these diagnostic tests are not required for evaluation of the urinary tract in e~ery traumatized animal. However, thorough evaluation will increase the number of urinary tract
67
THE UROGENITAL SYSTEM Observation
~Passes
Hematuria Alone
Easily• Obstruction __..Plain Radiograph)' " " / C o m p l e t e / Partial (Below)
Gently Catheterize
\
Hematuria/Dysuria
I
History Physical Examination
I1-----<"'-.. -'
Distended or Absent BlaQder/Inability to Urinate /Pel vic Practures/Retroper itoneal or Perineal Swelling/Uremia
I
Plain Radiography
~
~
\~ Abdominal
l \
Retroperitoneal swelling Lack of Renal Outline
Excretory
Urography~
\
Clin Path
Urethrography Cystography
.
.
Abdom1nal Flu1d
~
. Fluid~P~racent~sis
. D1:agnost1c Per1toneal
~Fluid
(CreatJ
Lavagl >
Blood\ (Creat)
Fluid /(Creat]
<
~~~~~~ l
Other Diagnostic Tests *Passage of catheter does not rule out incomplete disruption of urethra.
Figure 3. Algorithm for diagnosis of urinary tract injuries. The diagnostic work-up should end when the clinician is satisfied that the urinary tract is intact. The exact location of the injury should be identified before surgery is performed.
injuries that are detected. Surgical exploration without adequate preoperative examination can be frustrating and does not insure that the function and integrity of the urinary tract has been satisfactorily assessed. EMERGENCY MANAGEMENT OF UROGENITAL INJURIES
Traumatic injuries of the urogenital system that constitute true emergencies are limited to those conditions resulting in ongoing hemorrhage or the inability to void urine. Emergency therapy should be directed at controlling hemorrhage and providing a pathway for the discharge ofurine. Injuries to the urogenital system should be diagnosed as quickly as possible, but prolonged anesthesia for the surgical repair of urogenital system lesions should be avoided if the animal is uremic or unstable. Uremic animals are sensitive to the effects of most anesthetics, analgesics, and ~edatives, and the dosages of these should be decreased. 4 • 49 Unless absolutely necessary, it is preferable to treat the animal for shock and establish diuresis prior to administering depressive drugs. Diuresis may be achieved even when urine is leaking into the abdomen. Urine will usually continue to accumulate in the bladder after it has been ruptured. 7 A urethral catheter will keep the bladder decompressed, but urine may still enter the peritoneal cavity. A catheter that is inadvertently passed through a defect in the urethra or bladder wall may drain some
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Figure 4. The end of the urethral catheter should be drawn back into the bladder. The combined drainage of the urethral catheter in the bladder and the dialysis catheter in the abdominal cavity allow diuresis despite the presence of a ruptured bladder.
urine from the abdomen. A simple intra-abdominal catheter does not remove fluid from the abdomen as effectively as a dialysis catheter (Fig. 4). 39
Commercially available dialysis catheters may be placed in a closed manner by inserting the catheter with its trocar in place into the abdomen through a stab wound in the skin. An alternative technique is to make a small incision in the linea alba and insert the catheter through the incision. This technique decreases the amount of hemorrhage caused by insertion of the catheter and decreases the risk of penetrating underlying viscera. Unless scars from previous abdominal surgery are present, the catheter should be inserted through the midline 2 to 4 em caudal to the umbilicus. As the catheter is being placed, the tip should be directed caudally. Once urine outflow has been established, diuresis may be initiated. Intravenous fluids should be given at a rate sufficient to correct dehydration and produce a urine flow of 3 to 6 ml per kg per hr. Dehydration should be corrected over the first two to three hours of fluid administration. Isotonic solutions may initially be given at a rate of 20 to 40 ml per kg per hr to produce diuresis. Fluid input should be adjusted with respect to urine outflow to maintain diuresis but avoid overhydration. If obstruction or disruption of the lower urinary tract prevents passage of a urethral catheter, the bladder may be kept temporarily decompressed by any of three methods: cystocentesis, a cystostomy catheterization, or marsupialization of the bladder. 3· 27 Cystocentesis is the preferred method for temporary decompression since it takes less time and does not require anesthesia or surgery. However, over a period of days multiple punctures of the bladder may be necessary. While this rarely causes problems with a normal bladder, these puncture sites may not seal properly if the bladder wall is diseased or distended. Marsupialization of the bladder or placement of a cystostomy catheter both require a brief surgical procedur.e and increase the potential of urinary tract infection. A cystostomy catheter is preferable to marsupialization of the bladder because a second surgical procedure is not needed to remove the catheter. Also, contamination of the urinary tract is not controllable during marsupialization of the bladder. A cystostomy catheter may also be left in place following urethral or bladder surgery to insure drainage of urine (Fig. 5). 38 A small (8 Fr. or smaller) Foley catheter is u~ed as a cystostomy catheter. The catheter should be drawn through a stab wound in the abdominal wall lateral to the midline incision. Two retention sutures are
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Figure 5. Cystostomy using a Foley catheter. The omentum may be draped or tacked around the point of entry of the catheter into the bladder to help prevent leakage of urine around the catheter.
placed to hold the bladder near the abdominal wall. The catheter is placed through the center of a pursestring suture on the cranioventral aspect of the bladder. The pursestring suture is tied and may be used to secure omentum around the puncture site in the bladder wall. The bulb of the catheter should be inflated with sterile saline. The abdominal wound is closed, and the catheter is sutured to the skin. The catheter is then attached to a closed drainage system. These catheters have been removed percutaneously as early as three days after placement without evidence of urine leakage. Emergency surgery may be needed to control hemorrhage from the urogenital system. The patient's blood volume should be maintained by intravenous administration of balanced salt solution, whole blood, or plasma. The use of whole blood or plasma should be considered when the packed cell volume and plasma total solids drop below 20 per cent and 3.5 gm per 100 ml, respectively. 18 TREATMENT OF UROGENITAL INJURIES Kidneys Renal injuries, classified as contusions, lacerations, severe fractures, and pedicle injuries, 28 are usually diagnosed by contrast radiography or at exploratory laparotomy. Unless it can be clearly demonstrated that they are interfering with renal function, contusions of the kidneys should be left undisturbed. 2• 20 Minor lacerations of the capsule and parenchyma may usually be closed with sutures to control hemorrhage, but severe fractures of the parenchyma may necessitate partial or total nephrectomy. 2• 20 Exploration of the perirenal retroperitoneal space and examination of the kidneys are facilitated by atraumatic occlusion of the renal vasculature. 2• 20 Severe injuries confined to a pole of the kidney may be treated by partial nephrectomy. Damaged parenchyma is removed, and the vessels supplying this area are ligated. Exposed renal parenchyma is covered with omentum and secured with mattress sutures through the renal parenchyma (Fig. 6). 4 Generalized crushing of the kidney or damage to the vascular pedicle may necessitate nephrectomy. Preservation of a normally functioning kidney after severe injury to the pedicle is rare. 28 Renal vascular repair should be
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Figure 6. Partial nephrectomy. After the damaged portion of the kidney has been debrided, the cut surface is covered by tacking omentum to the capsule. (From Kolata, R. J.: Abdominal trauma. Compend. Contin. Ed., 1:445-453, 1979; with permission .)
approached with caution and must be performed within two hours of injury to prevent ischemic necrosis of the kidney. 2 Ureter
The ureter in the dog is small and the difficulty of its repair has been previously noted. 9 At surgery, injuries of the ureter are best located by retrograde catheterization of the ureters following a ventral cystotomy. 10 Flushing sterile saline through the ureters will usually demonstrate a defect. Avulsion of the ureter from the kidney may be treated by reimplantation of the ureter in the renal pelvis. This is extremely difficult in the dog and cat when the ureter and renal pelvis are not dilated. Traumatic injuries that do not leave a satisfactory length of healthy ureter attached to the kidney for anastomosis may necessitate nephrectomy. It has been stressed that a strip of ureter bridging a defect should be preserved to promote healing. 8 · 12 However, adequate debridement usually creates a complete gap in the ureter. 8 The blood supply of the ureter is longitudinal, being derived cranially from the renal artery and caudally from the urogenital artery. The ends of the ureter should not be stripped of their blood supply during debridement. The kidney and its blood supply may be mobilized and drawn caudally to decrease tension on the site of anastomosis. Spatulation of the ends of the ureter by small longitudinal incisions to increase the diameter of the suture line is recommended (Fig. 7).9 A tensionless , watertight closure of the ureter should be performed over a catheter using small gauge (5-0 to 6--0) absorbable suture. 8 · 12 Absorbable suture material is recommended for use in the urinary tract to decrease the potential for calculi formation on implanted, nonabsorbable suture. 31 • 52 While either chromic gut or synthetic absorbable sutures are satisfactory for use in the urinary tract, synthetic absorbable products may
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Figure 7. The debrided ends of a damaged ureter are spatulated by making small longitudinal incisions in the ends of the ureter. This increases luminal diameter when the ureteral anastomosis is completed.
be preferable as they stimulate less inflammation during their degradation.31· 38 It has been suggested that catheters left in the ureter during healing lead to , infection and fibrosis. 8 Intraluminal catheters cause reversible inflammatory changes in the wall of the ureter and may lead to transient ureteral obstruction after their removal. A ureteral catheter that is too tight may cause increased fibrosis .51 However, diversion of urine from the healing area of the ureter appears to enhance healing, 19· 32 and routine stenting of the ureter following repair is recommended. 35 Silas tic and rubber tubing appear to be superior to polyethylene tubing as ureteral stents. 35 The ureteral catheter may be used to drain the kidney and may be externalized through the urethra or across the bladder wall through the abdomen. Injuries to the distal third of the ureter are best treated by reimplantation of the ureter into the bladder (ureteroneocystostomy). The ureter should be placed through a tunnel in the bladder wall approximately five times the ureteral diameter in length. 44 This is to prevent reflux of urine from the bladder into the ureter. The end of the ureter is spatulated and sutured to the bladder mucosa. Excessive tension on the site of reimplantation is avoided by freeing the associated kidney and drawing it caudally or by fixing the bladder in a more cranial position (psoas-hitch procedure). To displace the bladder cranially, the ligaments of the bladder are partially incised, taking care to preserve the blood supply. After the ureter has been reimplanted, the bladder is pulled cranially on the side of the injured ureter and tacked to the fascia of the sublumbar musculature with absorbable sutures. 50
Bladder Lacerations of the bladder wall should be debrided and closed. If the tear is located near a ureteral orifice, the ureter should be identified and
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catheterized to prevent inadvertent ureteral obstruction or injury. The bladder may have to be distended with sterile saline to identify defects. in the bladder wall. The bladder should be carefully examined, as multiple lacerations may result from blunt or penetrating trauma. The bladder is kept decompressed following surgery by allowing frequent urination or with an indwelling catheter. Urethra Traumatic injuries of the urethra occur almost exclusively in the male dog and cat. 38• 40 The urethra of the female may be damaged during catheterization. The urethra, like the ureter, will regenerate over a catheter if a viable strip of tissue bridges a defect. 52 This method of treatment should generally be reserved for very small lacerations or punctures of the urethra. Large defects may require the presence of a catheter for three to four weeks to completely heal. 52 Most traumatic lacerations of the urethra should be treated by debridement and primary repair using absorbable suture (30 or 4-0) in a simple interrupted pattern. 40 Damage to prostatic tissue overlying the urethra may make primary repair of the prostatic urethra difficult. Partial or total removal of the prostate gland may be required to allow repair of the prostatic urethra. Repair of the urethra should not be attempted without adequate exposure. Exploration of the pelvic urethra may require a trans-symphyseal approach33 or reflection of a portion of the pubis. 21 Diversion of urine through either a urethral or a cystostomy catheter, or both, is recommended during healing of urethral defects. 3 • 29 • 38 Urethral stricture and urinary incontinence are frequent complications following traumatic urethral injuries. 38• 53 A catheter that distends the urethra will enhance stricture formation. 52 Urinary incontinence can result from primary damage to the innervation and blood supply of the urethral sphincter or iatrogenic damage to these structures during surgical intervention. Some degree of urinary incontinence was observed in five of six dogs that were evaluated nine months or more after prostatectomy. 17 Primary repair of the urethra should not be attempted if the defect in the urethra is too large to close without tension on the suture line. Large segmental defects in the urethras of male dogs have been treated by extrapelvic anastomosis of the bladder to the penile urethra24 and by antepubic urethrostomy. 53 Extrapelvic anastomosis of the bladder to the urethra is done by first incising the urethra near the neck of the bladder. The bulb of the penis (formerly called the urethral bulb), the penile urethra, and the bulbospongiosus and retractor penile muscles are severed. The distal cut end of the bulb of the penis is brought cranially through the abdominal incision, and the penile urethra is anastomosed to the urethra near the neck of the bladder (Fig. 8). If intact, the animal should be castrated. Antepubic urethrostomy may be performed in male or female animals. The maximum amount of viable intra-abdominal and pelvic urethra should be identified, dissected free, and preserved to maintain urinary continence and provide a sufficient length of urethra to lead from the bladder to the abdominal wall. It may be necessary to separate the pelvic symphysis. In males, the urethrostomy opening will be located 2 to 3 em lateral to the
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THE UROGENITAL SYSTEM Anastomosis
Figure 8. Extrapelvic anastomosis of the bladder to the penile urethra. The bulbous portion of the urethra is anastomosed to the neck of the bladder within the abdomen. (Adapted ·from Knecht, C. D., and Slusher, R.: Extrapelvic anastomosis of the bladder and penile urethra in a dog. J. Am. Anim. Hosp. Assoc., 149:1729-1734, 1966.
prepuce, while in females the stoma will be on or near the midline. Care should be taken when performing the urethrostomy to avoid bending the urethra too sharply, resulting in obstruction of the urethra. The severed end of the proximal urethra is spatulated with a small incision on its ventral surface, and the urethra is secured to the skin with nonabsorbable sutures in an interrupted pattern (Fig. 9). Male Reproductive Tract
Laceration of the tip of the penis or external urethral meatus should be carefully debrided and sutured with small gauge (4-0) nonabsorbable suture. A tourniquet around the proximal penis will decrease the amount of blood in the field and improve the precision with which sutures are placed. 38
Figure 9. Antepubic urethrostomy. The proximal urethra is brought through the midline (female) or in a paramedian location (male), and the urethra is sutured to the skin. (Adapted from Yoshioka, M. M., and Carb, A. : Antepubic urethrostomy in the dog. J. Am. Anim. Hosp. Assoc., 18:290-294, 1982.)
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Fracture of the os penis may result in occlusion or disruption of the penile urethra. If a catheter can be passed and the fragments are well aligned, the fracture may heal satisfactorily without further treatment. If the fragments are badly displaced or shattered, surgery can be performed to realign the fragments or remove the os penis. 2 A prescrotal urethrotomy will allow catheterization of the bladder if a urethral catheter will not pass through the penile urethra. Extensive damage to the penile urethra or subsequent stricture formation may necessitate the creation of a permanent urethrostomy proximal to the site of injury. Minor lacerations of the scrotum may usually be closed primarily with or without placement of a drain. It is difficult to satisfactorily treat established scrotal or testicular infections with antibiotics and drainage. Castration and scrotal ablation is often the best method of treatment for infected or badly contaminated lacerations and puncture wounds of the scrotum.
Female Reproductive Tract The female reproductive tract is rarely traumatized. Lacerations of the external genitalia may be sutured. An episiotomy should be performed when appropriate to increase exposure of the vaginal vault and urethral orifice. Catheterization of the urethra prior to repair of injuries of the vaginal floor will prevent accidental occlusion of the urethra. Antepubic urethrostomy may also be performed in the female dog following injury to the urethra or removal of the vagina. 53 The uterus is most likely to be traumatically injured when gravid. Possible sequelae to uterine trauma include metritis, peritonitis, abortion, fetal death, and hemorrhage. Disruption of the uterine wall does not inevitably lead to fetal death or pyometra, and minor lacerations may be sutured. 42 The owner should be warned of the possible adverse effects of traumatic injuries on the fetuses. Hemorrhage or loss of blood supply and extensive injury to the uterus may necessitate ovariohysterectomy.
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38. Rawlings, C. A., and Wingfield, W. E.: Urethral reconstruction in dogs and cats. J. Am. Anim. Hosp. Assoc., 12:850-860, 1976. 39. Root, H . D., Hauter, C. W., McKinley, C . R., et al.: Diagnostic peritoneal lavage. Surgery, 57:633-637, 1965. 40. Selcer, B. A.: Urinary tract trauma associated with pelvic trauma. J. Am. Anim. Hosp. Assoc., 18:75--793, 1982. 41. Shah, P. M., Kin, K.-H ., Ramirez-Schenb, G., et al.: Elevated blood urea nitrogen: An aid to the diagnosis of intraperitoneal rupture of the bladder. J. Urol., 122:741-743, 1979. • 42. Smith, K. W. : Female genital system. In Archibald, J. (ed.): Canine Surgery. Edition 2. Santa Barbara, California, American Veterinary Publications, Inc., 1974. 43. Sullivan, M. J., Lackner, L. U. , and Barowsky, L. H. W. : Intraperitoneal extravasation ofurine. }.A.M.A., 221:491-492, 1972. 44. Tarvin, G. B.: Surgical treatment of ectopic ureters. VET. CLIN. NORTH AM.: SMALL ANIM. PRACT., 9:277-284, 1979. , 45. Thai, E . R.: Evaluation of peritoneal lavage and local exploration in lower chest and abdominal stab wounds. J. Trauma, 17:642-648, 1977. 46. Thayer, G. W., Carrig, C. B., and Evans, A. T.: Fatal venous air embolism associated with pneumocystography in a cat. J. Am. Vet. Med. Assoc., 176:643-645, 1980. 47. Thornhill, J. A. , and Cechner, P. E.: Traumatic injuries to the kidneys, ureter, bladder and urethra. VET. CLIN. NORTH AM.: SMALL ANIM. PRACT., 11:157-170, 1981. 48. Thrall, D. E., and Finco, D. R. : Canine excretory urography: Is quality a function of BUN? J. Am. Anim. Hosp. Assoc., 12:446-450, 1976. 49. Trim, C . : Anesthesia and the kidney. Compend. Contin. Ed., 11:843-847, 1979. 50. Warwick, R. T., and Worth, P. H. L.: The psoas-hitch procedure for the replacement of the lower third of the ureter. Br. J. Urol., 4:701-709, 1969. 51. Weaver, R. G. : Basic surgical principles of ureteral repair. Surg. Gynecol. Obstet., 110:594-600, 1960. . 52. Weaver, R. G., and Schultz, J. W.: Experimental and clinical studies of urethral regeneration. Surg. Gynecol. Obstet., 115:729-736, 1962. 53. Yoshioka, M. M., and Carb, A. : Antepubic urethrostomy in the dog. J. Am. Anim. Hosp. Assoc., 18:290-294, 1982. Department of Small Animal Medicine College of Veterinary Medicine University of Georgia Athens, Georgia 30602