Trauma of the adult bladder and urethra

Trauma of the adult bladder and urethra

Traumaof the Adult BladderandUrethra By John A. Bonavita T RAUMA to the lower urinary tract, while not commonplace, is seen in every radiologic prac...

6MB Sizes 0 Downloads 79 Views

Traumaof the Adult BladderandUrethra By John A. Bonavita

T

RAUMA to the lower urinary tract, while not commonplace, is seen in every radiologic practice. Unfortunately, it may lead to serious complications. Prompt and judicious radiologic evaluation is the keystone to the successful management of these potentially devastating injuries. Hence, the radiologist must be well acquainted not only with the anatomy of the lower urinary tract and the mechanisms of injury in this area, but also with the appropriate radiologic approach to accurate diagnosis. BLADDER In adults, the urinary bladder is housed within the protective encasement of the bony pelvis.’ On the other hand, in children, the bladder extends well into the peritoneal cavity and is consequently more susceptible to blunt injury.2 The type, severity, and indeed actual occurrence of injury to the urinary bladder is related not only to the mechanism of injury but also to the size and distensibility of the bladder at the moment of impact; ie, a full or obstructed bladder or one that is fixed in position by scar or tumor is most likely to be ruptured.3s4

Anatomy The urinary bladder is located extraperitoneally within the Retzius space. The symphysis pubis abuts its anterior border, while laterally it is bound by the obturator internus muscles, bony pelvis, and lateral umbilical ligaments. Its base is anchored inferiorly by the urogenital diaphragm. The Denonvilliers fascia (rectovesical fascia) forms a loose posterior reflection. The dome of the bladder is mobile and distensible.’ There is abrupt transition in differential mobility between the bladder and trigone, predisposing this site to the development of intraperitoneal tears. Mechanism of Injury. Motor vehicle accidents and sports injuries produce most injuries of the bladder. However, surgeons and even radiologists may also be culpable.‘,4 There is an equal distribution of intraperitoneal and extraperitoneal rupture of the bladder; about 10% are combined.‘.4,6 Due to its intimate relationship with the bony pelvis, extraperitoneal Semtnars m Roentgenology,

Vol. XVIII, No. 4 (October).

1983

and Howard

M. Pollack

rupture of the bladder is almost invariably associated with pelvic fracture (5% of patients with pelvic fracture have extraperitoneal rupture of the bladder; 95% of patients with the latter injury will have pelvic fracture).h,7 Roughly half of lower urinary tract injuries in patients with pelvic fracture involve the urethra alone, a third the bladder alone, and about 10% involve both.J The great majority of these pelvic fractures are Malgaigne’s or pubic ring fractures,’ in which there is a major vertical disruption of the pelvic arch (Fig. 1). The instability of the pelvis produced by this fracture often results in a tear in the base of the bladder or prostatic urethra. Conversely, bony spicules from even a minor pelvic fracture may directly puncture the bladder.‘.‘,’ In children, diastasis with subsequent elastic recoil of the symphysis or sacroiliac joints may suffice to produce injury to the bladder.” The bladder, especially when full, may be injured by a direct blow to the abdomen without bony injury. Evaluation. Any patient with a pelvic arch fracture or with the combination of abdominal trauma, pain, and inability to void should be considered as having a possible bladder injury. Hematuria is almost invariable in bladder injuries.’ Retrograde cystography is the keystone in evaluating the traumatized bladder. Intravenous urography is inadequate for this purpose because of dilution of the contrast material within the bladder and because resting intravesical pressure is too low to demonstrate a small tear. Even with __-.-...-.

_I_

From the Departments of Radiology, Crozrr-Chester Medical Center, Chester. PA, and the Hosprtal of the University of Pennsylvania, Philadelphia, PA. Howard M. Pollack: Professor of Radiology, University of Pennsylvania School of Medicine and Hospital; Department of Radiology, Hospital of the University of Petm~~~lvania. John A. Bonavita: Clinicaf Assistant Professor ofRadiology. University of Pennsylvania School of Medicine und Hospital; Department c?f Radiolog,~. Crozer-Chester Medical Center. Address reprint requests to Howard M. PollacL, M.D.. Department of Radiology, Hospital oJ thr L’nivrrsity of Pennsylvania. 3400 Spruce Street, Philadelphia. PA 19104. @31983 by Grune & Stratton, Inc. 0037~/98x/83/1804~0009$01.00/0

299

BONAVITA

AND POLLACK

Malgaigne fracture. Disruption of the pelvic arch Fig. 1. with diastasis of the symphysis pubis (solid arrow) and right sacroiliac joint (open arrow). The right half of the pelvis in this unstable fracture moves independently of the left. subjecting the lower urinary tract to a high risk of disruption.

retrograde cystography, up to 10% of bladder ruptures may be missed.‘-” There are many reasons for this: a small tear may seal spontaneously, concomitant urethral rupture may interfere with evaluation of the bladder,“,” and inappropriate filming may preclude accurate evaluation.” Only if there is no suspicion of urethral injury should a Foley catheter be advanced into the bladder. If there is any question, a urethrogram should be done first. Under fluoroscopic control, a 30% concentration of iodinated contrast material is instilled into the bladder until a detrusor contraction is provoked. Multiple films in several projections, including AP and both obliques, should be performed (Fig. 2). A postdrainage film should also be obtained lest a small extraperitoneal rupture of the bladder be missed. When there is an intraperitoneal tear of the bladder, contrast will fill the cul-de-sac and outline loops of bowel (Fig. 3). As more contrast medium enters the peritoneal cavity, it will extend into the paracolic gutters. This contrast is free-flowing and will not appear streaky. In extraperitoneal rupture of the bladder, contrast is not free-flowing and will tend to streak in

Fig. 2. Value of retrograde cystography in bladder trauma. (A) AP film of the bladder following intravenous urography appears normal. (Bj Right posterior oblique view of the bladder during retrograde cystography 3 hr later demonstrates a small extraperitoneal tear of the bladder (arrows).

a flamelike fashion, since it lies within the narrow confines of the extraperitoneal space (Fig. 4). Combined intra- and extraperitoneal rupture of the bladder will demonstrate both sets of findings (Fig. 5). Treatment. The primary aim of therapy is the adequate closure of the bladder defect. Contusion and small extraperitoneal tears of the bladder are therefore managed conservatively. All other injuries of the bladder should be repaired operatively. The aims of such therapy

TRAUMA

lntraperitoneal rupture of the Fig. 3. bladder. AP film of the pelvis following cystography demonstrates massive intraperitoneal extravasation of opecified urine into the cul-de-sac (solid arrow) and flanks (open arrows).

are (1) closure of the bladder defect, as noted, (2) adequate urinary diversion away from the area of injury, and (3) prompt drainage of extravasated urine.

external urethral sphincter, and superficial fascia of the perineum. Thus, neither the membranous urethra nor apex of the prostate are mobile, thereby predisposing to shear injuries. The anterior urethra is comprised of bulbous

URETHRA

Urethral injuries are almost twice as common as bladder injuries. Up to 12% of patients with pelvic fracture will have a urethral injury.‘* Due to the short course of the female urethra, these lesions almost invariably occur in men.13

Anatomy In the male, the urethra is divided into two portions, posterior and anterior. The posterior urethra is composed of the prostatic and membranous urethra. The prostatic urethra is that portion between the bladder base and verumontanum. It is approximately 3.5 cm in length and traverses the anterior portion of the prostate. Attached to the membranous urethra by the external urethral sphincter and to the symphysis by the medial puboprostatic ligaments, the apex of the prostate is relatively immobile. The base of the prostate is more mobile and is attached to the bladder and bony pelvis. The membranous urethra is contained entirely within the urogenital diaphragm, which is made up of the levator ani, transverse perinei muscles,

Fig. 4. Extraperitoneal rupture of the bladder following pelvic fracture. Postdrainage film following retrograde cystography demonstrates flame-shaped extravasation into the extraperitoneal perivesical space bilaterally.

BONAVITA

302

AND POLLACK

Combined intraand extraperitoneal Fig. 6. rupture of the bladder following trocar cystostomy. AP film of the pelvis following cystography demonstrates both a huge extraperitoneal flame-shaped extravasation (solid arrow) and a small intraperitoneal contrast leak in the right flank (open errowj.

and pendulous portions. The bulbous portion extends from the urogenital diaphragm to the junction between the scrotum and penis. It lies within the superficial perineal space beyond the urogenital diaphragm. The pendulous urethra lies entirely within the penis. The corpus of the penis is made up of the paired corpora cavernosa and the single corpus spongiosum. Each corpus is covered individually by a deep fibrous sheath known as the tunica albuginea. Collectively, they are covered by the Buck fascia, which separates the deep from the superficial compartments of the penis. Posterior Urethra

Type II injury of the posterior urethra secondary Fig. 6. to pelvic fracture. Retrograde urethrogram demonstrates extravasation of contrast medium from the prostatomembranous urethra above the level of the urogenital diaphragm. Urethral continuity is not disrupted. Although oblique views are usually more informative, the AP view was most helpful in this case.

The posterior urethra is the most common site of lower urinary tract injury.4,‘4,‘5 In addition to their relative frequency, these injuries are also debilitating in terms of morbidity and complications. Mechanism of Injury. Because of the relative differences in mobility of the membranous urethra and the prostate, tears of the prostatomembranous urethra are usually the result of shearing forces rather than direct penetration by bony spicules. As the body comes to a rapid halt at the moment of traumatic impact, the mobile prostatic urethra continues to move in a forward direction while the membranous urethra stops, resulting in shearing of the puboprostatic ligaments.5 Conversely, when the pelvic arch is fractured, the membranous urethra will remain

TRAUMA

Fig. 7. Type III injury of the posterior urethra secondary to pelvic fracture with symphysis separation. Retrograde urethrogram demonstrates massive extravasation both above and below the damaged urogenital diaphragm. AP views are usually sufficient for diagnosis in cases as severe as this.

firmly attached to one side of the pelvis, while the prostatic urethra moves with the other, resulting in shearing.3 Evaluation. The presence of a pelvic arch fracture in a male should raise the suspicion of a posterior urethral injury. If blood is present at the urethral meatus independent of urinary stream, if the patient is unable to void, or if the bladder is palpable, there is a high likelihood of

Fig. 8. Posttraumatic stricture of the prostatomembranous urethra. Combined antegrade and retrograde urethrogram demonstrates a filiform caliber stricture of the urethra following a type II posterior urethral injury with attempted primary repair. Note severe proximal dilatation.

303

urethral injury.14 Under these circumstances, a Foley catheter should not be advanced into the bladder. Hematuria is commonly seen with urethral injury. In fact, the pattern of hematuria may itself be helpful: initial hematuria with terminal clearing is indicative of urethral injury; blood and urine admixed throughout voiding favors bladder injury. Retrograde urethrography is the only safe and reliable method of diagnosing posterior urethral injury. Although optimally performed under fluoroscopic control, it may be performed as a portable examination when necessary. To prevent geometric foreshortening of the urethra, both the pelvis and external genitalia should be obliqued 60°. The urethral meatus may be occluded either by direct insertion of a catheter tip syringe or by the passage of a Foley catheter into the fossa navicularis, after which the balloon is inflated with 2 cc of water. In view of the simplicity and accuracy of retrograde urethrography, there is currently no role for the “diagnostic catheter.“4.‘5 It may convert a sterile extravasation into an infected urinoma, or a minor tear into a catastrophic laceration, and may lead to a false negative or false positive diagnosis. A radiologic classification of posterior urethral injuries that correlates with the extent of the tear and the subsequent course has been proposed by Colapinto and McCallum’h and later modified by Sandler et al.14 This scheme is not dependent on the exact site of rupture, which is often impossible to demonstrate either surgically or radiographically, but is based more on severity. In type I injuries, mere stretching of the posterior urethra by hematoma within the pros-

BONAVITA

AND POLLACK

Fig. 9. Foreign body in anterior urethra. Bobby pin, inserted by the patient, lies within the anterior urethra. Urethral laceration frequently complicates insertion of foreign objects.

tatic bed occurs. No extravasation is noted. In type II, the classic injury, rupture occurs in the prostatic urethra or at the prostatomembranous junction, but extravasation is limited inferiorly by the intact urogenital diaphragm (Fig. 6). In type III injuries, both the urethra and urogenital diaphragm are torn; extravasation is seen both above and below the diaphragm (Fig. 7). In some

instances, extravasation extends so high that it may be impossible to determine whether it is the bladder or the urethra (or both) that is ruptured. The ability to fill the bladder usually indicates a type I or incomplete type II injury. Management. The management of posterior urethral injuries is highly controversial, a reflection of guarded outcome regardless of therapy. Whether immediate or delayed, the aims of therapy are to promote resorption of hematoma, prevent infection, and maintain urethral alignment. The major immediate complication is infection, which may be controlled by prophylactic antibiotics and judicious surgical management. Long-term complications include sexual impotence, urinary incontinence, and almost inevitably, if the tear is complete, stricture formation (Fig. 8).

Anterior Urethra

Straddle injury of anterior bulbous urethra Fig. 10. caused by bicycle handlebar. Retrograde urethrogram reveals urethral laceration with extravasation in the superficial perineal space. Buck fascia and the corpus spongiosum have been breached. permitting contrast to extend beyond the confines of the deep portion of the penis.

Mechanism of Injury. The anterior urethra is much less commonly injured than the posterior portion.15 ,It is almost never damaged by pelvic fractures. A direct blow to the perineum (“straddle injury”) is the usual precipitating event. The passage of a foreign object (eg, catheter, cystoscope) by the physician or by the patient himself (Fig. 9) may produce injury. Evaluation. Anterior urethral injury should be suspected with direct trauma to the penis. As with the posterior urethra, meatal blood or the inability to void are frequent signs of injury. However, it is uncommon to see bladder outflow obstruction in anterior urethral injury, since it is

TRAUMA

not in proximity to the external urethral sphincter. Retrograde urethrography should be performed whenever the diagnosis is considered. This enables the injury to be classified as contusion or partial or complete tear.12 In contusion there is no extravasation because there is no tear. In a partial tear, continuity of the urethra is maintained, but extravasation occurs. With complete tear, total transection of the urethra takes place, with no continuity of mucosa. Extravasation is confined to the penis if the Buck fascia is intact. When the latter is lacerated, contrast medium may extend into the scrotum or anterior abdominal wall (Fig. 10). The penis itself may be fractured, especially if injured while erect. In this situation, following antegrade urethrography, cavernosography is the procedure of choice.‘7.‘8 A butterfly needle is inserted into the corpus just proximal to the glans penis on the lateral aspect of the corpus cavernosum. Contrast medium is injected directly into

Fig. 11. Fractured penis from blunt trauma. (A) Retrograde urethrogram shows the pendulous urethra to be intact but extrinsically compressed at the site of corporal fracture (arrow). (B) Corpus cavernosogram shows extravasation of contrast medium at the site of penile rupture (arrow). (Courtesy of Marc P. Banner, M.D.)

the corpus, and films are taken in both oblique and AP projections. Because of anastomoses, injection of either corpus cavernosum will fill both. If the penis is fractured, extravasation of contrast from the corpus cavernosum will be seen (Fig. 11). Penile hematoma is manifest by a soft tissue mass extrinsic to the corpus. Despite the fact that the diagnosis of ruptured penis may be clinically obvious, cavernosography may be of inestimable assistance to the urologist in localizing the exact site of rupture, discovering secondary sites of unsuspected rupture, and excluding communication with the urethra.lx Management. Treatment is directly related to the severity of tear. Contusion and partial tear may be treated by Foley catheterization, complete tears by surgery, either immediate or delayed. Early recognition and treatment will prevent the development of necrotizing fasciitis of the perineum (Fournier gangrene), the most severe and immediate complication.7 Stricture

BONAVITA

306

formation is the most common late complication. Its severity is directly related to both the severity of the tear and the adequacy of treatment. REFERENCES 1. Bright TC, Peters PC: Injuries urethra. In: Harrison JH, et al (eds): Philadelphia: Saunders, 1978;906-930 2. Reid RE, Herman JR: Rupture urethra: Diagnosis and treatment. 1965;65:2685-2696

to the bladder and Campbell’s Urology. of the bladder and NY State J Med

3. Flaherty JJ, Kelly R, Burnett B, et al: Relationship of pelvic bone fracture patterns to injuries of the urethra and bladder. J Ural 1968;99:297-300 4. Clark SS, Prudencio RF: Lower urinary tract injuries associated with pelvic fractures: Diagnosis and management. Surg Clin North Am 1972;52:1833201 5. Sandler CM, Phillips JM, Harris JD, et al: Radiology of the bladder and urethra in blunt pelvic trauma. Radio1 Clin North Am 1981;19:195-21 I 6. Waterhouse K, Gross M: Trauma to the genitourinary tract: A 5-year experience with 251 cases. Trans Am Assoc Genitourin Surg 1968;60: 162-l 67 7. Lavallee G, Gregoire A, Laperriere J, et al: Lower urinary tract trauma. J Can Assoc Radio1 1979;30:49-52

AND POLLACK

8. Brossman SA, Fay R: Dtagnosis and management of bladder trauma. J Trauma 1973;13:687-694 9. Weyrauch HM Jr, Peterby RA: Test for leakage in early diagnosis of ruptured bladder. J Urol 1940;44:264-273 10. Reiser C, Nicholas E: Rupture of the bladder: Unusual features. J Urol 1963;90:53-57 1 I. Lieberman AH, Walden TB, Bogash M, et al: Negative cystography with bladder rupture: Presentation of 2 cases and review of the literature. J Urol 1980;123:428-430 12. Antoci JP, Schiff M Jr: Bladder and urethral injuries in patients with pelvic fractures. J Urol 1982;128:25-26 13. Corriere JN Jr, Harris JD: The management of urologic injuries in blunt pelvic trauma. Radio1 Clin North Am 1981;19:187-194 14. Sandler CM, Harris JD, Corriere JN, Jr., et al: Posterior urethral injuries after pelvic fracture. AJR 1981;137:1233-1237 15. Mitchell JP: Injuries to the urethra. Br J Urol 1968;40:649-670 16. Colapinto V, McCallum RW: Injury to the male posterior urethra and fractured pelvis: A new classification. J Urol 1977;118:575-580 17. Velcek D, Evans JA: Cavernosography. Radiology 1982;144:781-785 18. Grosman H, Gray RR, St Louis EL, et al: The role of cavernosography in acute “fracture” of the penis. Radiology 1982;144:787-788