of urethral injuries after Pelvic Trauma: Evaluation with urethrography.

Transcription

1 Note: This copy is for your personal, non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, use the RadioGraphics Reprints form at the end of this article. ABDOMINAL EMERGENCIES Urethral Injuries after Pelvic Trauma: Evaluation with Urethrography Online-Only CME See /rg_cme.html LEARNING OBJECTIVES After reading this article and taking the test, the reader will be able to: Identify patients at risk of urethral trauma and those in need of urgent ascending and descending urethrography. Describe the adaptations to standard urethrographic technique that may be necessary for an accurate initial evaluation in patients with pelvic trauma. Recognize the imaging findings that allow the identification and classification of urethral injuries due to pelvic trauma. Mark D. Ingram, MA, MBBS, MRCP Sarah G. Watson, MA, MBBS, MRCS Philippa L. Skippage, MBChB, MRCP, FRCR Uday Patel, MBChB, MRCP, FRCR Urethral injury is a common complication of pelvic trauma that, if undiagnosed, may lead to significant long-term morbidity. Segments of the urethra that are near the pubic rami and the puboprostatic ligaments are particularly vulnerable. Although computed tomography is commonly used for the initial imaging evaluation of patients with polytrauma, urethral injury is better assessed and classified by using urethrography. Complete urethral imaging is especially important at presentation because the insertion of a transurethral bladder catheter may exacerbate an existing injury (eg, cause a partial urethral tear to become a complete transection). However, even for radiologists who are familiar with standard technique, urethrography after pelvic trauma may be particularly challenging because the patient is immobile or a surgical fixation device or indwelling urethral catheter is present. Various methods may used to overcome these difficulties and ensure that optimal images are obtained so that a correct diagnosis can be made without additional imaging evaluations. RSNA, 2008 radiographics.rsnajnls.org TEACHING POINTS See last page Abbreviation: AAST = American Association for the Surgery of Trauma RadioGraphics 2008; 28: Published online /rg Content Codes: 1 From the Department of Radiology, St George s Hospital, Blackshaw Road, Tooting, London SW17 0QT, England. Recipient of a Certificate of Merit award for an education exhibit at the 2007 RSNA Annual Meeting. Received January 29, 2008; revision requested March 13 and final revision received April 7; accepted April 9. All authors have no financial relationships to disclose. Address correspondence to M.D.I. ( markd_ingram@yahoo.co.uk). RSNA, 2008

2 1632 October Special Issue 2008 RG Volume 28 Number 6 Teaching Point Introduction Urethral injury is a common complication of pelvic trauma; it occurs in as many as 24% of adults with pelvic fractures (1). Unless urethral injuries are associated with major bladder trauma, they are rarely life-threatening in the acute phase. However, they may lead to significant long-term morbidity (2). Strictures have been reported in 31% 69% of patients after a complete disruption of the bulbous urethra (3). Incontinence and impotence are other well-recognized associ- ated problems. The severity and duration of such complications may be reduced if urethral injury is promptly diagnosed and appropriately treated, and in this the radiologist plays a key role. Most patients with polytrauma undergo computed tomography (CT) for the initial survey of their injuries. However, for the accurate identification and classification of urethral injuries, high-quality urethrography must be integrated into the imaging protocol. The article first reviews the anatomy of the urethra in male and female patients and the reasons for its vulnerability to injury. Next, the clinical and imaging manifestations of urethral injuries, the classification of those injuries, and the correlative treatment options are described. Urethrographic technique is discussed in detail, with an emphasis on modality modifications that may allow higher-quality urethral imaging in patients with pelvic trauma. Normal Urethral Anatomy Figure 1. Schematic shows the normal male urethral anatomy in the sagittal plane. During urethrography after pelvic trauma, it is important to identify the location of the bladder neck (white asterisks) and the external urethral sphincter or urogenital diaphragm (red asterisks) because these are key anatomic landmarks when classifying urethral injury. VM = verumontanum. (Reprinted, with permission, from reference 4.) Male Subjects The male urethra extends from the base of the bladder to the external urethral meatus. It is divided into four parts: the prostatic and membranous segments (the posterior urethra) and the bulbous and penile segments (the anterior urethra). The anterior and posterior urethra are separated by the urogenital diaphragm (Fig 1) and anchored to the anterior pubic arch by paired puboprostatic ligaments. The prostatic urethra is approximately 3.5 cm long. It tapers toward the membranous urethra, which ends at the urogenital diaphragm. The internal urethral sphincter, which is responsible for passive continence, extends from the bladder neck through the prostatic urethra and is composed of smooth muscle. The external urethral sphincter, which is responsible for active continence, is located within the urogenital diaphragm and consists of striated muscle. The anterior urethra passes from the inferior aspect of the urogenital diaphragm through the corpus spongiosum to the external meatus. The bulbous urethra lies in the crura of the corpus spongiosum and is entirely internal. The penile urethra originates at the penoscrotal junction and is entirely external. Female Subjects The female urethral anatomy is less complex: The urethra passes from the bladder neck obliquely forward and downward, through the distal anterior vaginal wall. Along its course, it perforates the urogenital diaphragm. It ends in the external urethral meatus, anterior to the vagina. Mechanisms of Urethral Injury The urethra is vulnerable because of its close relation to the pubic bones and the puboprostatic ligaments. In men, the external portion is also susceptible to direct trauma from bone fragments arising from the pubic rami. The distal membranous urethra is especially at risk, and its injury may disrupt the active continence mechanism. The most common injury by far is that of the posterior urethra. Such injury occurs in 3% 25% of patients with pelvic fractures (5). The most common associated mechanisms of injury are road traffic accident and fall from a height. As many as 20% of patients with this type of injury have an associated bladder laceration, an injury that also may be assessed at urethrography (6). Teaching Point

3 RG Volume 28 Number 6 Ingram et al 1633 Table 1 AAST Classification System and Recommended Treatment for Urethral Injuries Injury Type Injury Description Urethrographic Appearance Treatment 1 Contusion Normal None 2 Stretch injury Elongation of the urethra without extravasation Conservative management with suprapubic or urethral cath- 3 Partial disruption Extravasation of contrast agent from the urethra with opacification of the bladder 4 Complete disruption Extravasation of contrast agent from the urethra without opacification of the bladder and with urethral separation of <2 cm 5 Complete disruption Complete transection with urethral separation of >2 cm or extension of injury to the prostate or vagina Source. Reference 11. eterization Conservative management with suprapubic or urethral catheterization Endoscopic realignment or delayed graft urethroplasty Endoscopic realignment or delayed graft urethroplasty Anterior urethral injury is seen in approximately 33% of patients because of the comparative mobility of the anterior urethra (5). Straddling injury, which results from compression of the urethra against the pubis, is the most frequent type of injury at this site. Coexisting pelvic fractures are less common. In rare cases, subtle anterior injuries are overlooked when there is no accompanying fracture, and strictures may occur later. Injury of the female urethra is rarer (<6% of female pelvic fractures) than that of the male urethra because of shorter length, internal location, increased elasticity, and less rigid attachment of the urethra to the adjacent pubic bones (7). Perry and Husmann (8) reported that 4.6% of women with pelvic fractures caused by road traffic accidents had bladder neck injuries extending into the urethra. Female urethral injury is usually seen in cases of severe pelvic trauma and, in female patients, often is associated with vaginal (75%) or rectal trauma (33%) (9). High-Risk Signs of Urethral Injury In male patients with pelvic trauma, the clinical signs that are suggestive of urethral injury include gross hematuria, blood at the meatus, inability to void, swelling or hematoma of the perineum or penis, and a high-riding prostate at digital rectal examination after a pelvic fracture or after significant lower abdominal or perineal trauma without a fracture (5). In female patients with pelvic trauma, clinical signs of possible urethral injury include vaginal bleeding, labial edema, voiding difficulty, blood at the meatus, hematuria, and urinary leak per rectum. After pelvic trauma, clinical attention is focused on the immediate management of life-threatening vascular and visceral injuries. However, if the presence of a urethral injury is suspected, urethrography should be performed to rule out such injury before a transurethral catheter is inserted, lest the catheter be misdirected through a urethral tear into a pelvic hematoma (10). Blind insertion of a catheter may increase the extent of a hemorrhage or may introduce an infectious agent into a previously sterile hematoma. It also may cause the extension of a partial tear into a complete tear. Classification of Urethral Injuries The two most commonly used systems of classification are that advocated by the American Association for the Surgery of Trauma (AAST) (11) and one that was originally proposed by Colapinto and McCollum (12) and subsequently revised by Goldman et al (6). Well-conducted urethrography allows correct injury classification, whatever the system used (5). In the AAST scheme, urethral injuries are broadly classified according to the treatment required, irrespective of their location; classification is concentrated more on the degree of disruption and urethral separation (Table 1).

4 1634 October Special Issue 2008 RG Volume 28 Number 6 Figure 2. Image from ascending urethrography in a male patient with an open-book pelvic fracture from trauma shows the posterior urethra (arrow), which appears stretched but intact (Goldman type I injury), with no evidence of contrast material extravasation. Figure 3. Image from ascending urethrography shows an area of contrast material extravasation (white arrow) indicative of injury to the posterior urethra, with an intact urogenital diaphragm (black arrow). These findings signify a Goldman type II injury. Table 2 Goldman System for Classification of Urethral Injuries at Urethrography Injury Type Injury Description Urethrographic Appearance I Stretching or elongation of the otherwise intact Intact but stretched urethra posterior urethra II Urethral disruption above the urogenital diaphragm while the membranous segment remains intact Contrast agent extravasation above the urogenital diaphragm only III Disruption of the membranous urethra, extending below the urogenital diaphragm and involving the anterior urethra Contrast agent extravasation below the urogenital diaphragm, possibly extending to the pelvis or perineum; intact bladder neck IV Bladder neck injury extending into the proximal urethra Extraperitoneal contrast agent extravasation; bladder neck disruption IVa Bladder base injury simulating a type IV injury Periurethral contrast agent extravasation; bladder base disruption V Isolated anterior urethral injury Contrast agent extravasation below the urogenital diaphragm, confined to the anterior urethra Source. Reference 6. Teaching Point The more widely accepted, unified classification system proposed by Goldman and colleagues emphasizes the anatomic location of an injury (eg, according to whether it is nearer to the urogenital diaphragm or the external sphincter). This system includes a category for bladder injuries that involve or simulate posterior urethral injury (Table 2). Accurate classification is important because it allows effective treatment planning. The ideal surgical approach is still debated (13). Some surgeons advocate immediate surgery, but most prefer suprapubic catheterization and delayed urethral repair. The choice appears to be a matter of available surgical skills (9), but the degree of injury also may influence the treatment decision. A patient with a Goldman type I injury (Fig 2) may be selected for conservative management, whereas an associated intraperitoneal, rectal, or bladder injury requires immediate surgery, in which case any associated urethral injury can be dealt with. Complete urethral disruption, as in Goldman type II V injuries (Figs 3 6), usually results in a severe stricture, and some surgeons select these cases for immediate surgery.

5 RG Volume 28 Number 6 Ingram et al 1635 Figure 4. Images from ascending urethrography (a) and descending urethrography with a suprapubic catheter (b), obtained in a male patient after pelvic fixation for trauma sustained in a road traffic accident, show a complete posterior urethral transection that extends through the urogenital diaphragm to the anterior urethra (arrow in a), with resultant extraperitoneal contrast material extravasation (black arrow in b). Because the bladder neck (white arrow in b) is intact, the injury was classified as Goldman type III. The base of the bladder is elevated because of a pelvic hematoma. Figure 5. Images from ascending urethrography (a) and descending urethrography performed with a suprapubic catheter (b) in a male patient with pelvic trauma show a complete transection of the posterior urethra with contrast material extravasation into the perineal soft tissues (arrow in a), as well as bladder neck disruption with further extraperitoneal contrast material extravasation (arrow in b). These findings are indicative of a Goldman type IV injury. Figure 6. Cystogram obtained in a male patient with an open-book pelvic fracture after a road traffic accident shows extraperitoneal contrast material extravasation extending from the bladder neck (arrow) around the proximal urethra, a finding indicative of a Goldman type IVa injury.

6 1636 October Special Issue 2008 RG Volume 28 Number 6 Figure 7. Images from ascending urethrography (a) and descending urethrography performed with a suprapubic catheter (b) in a male patient several months after pelvic trauma show no filling of the membranous segment of the urethra because of a stricture in the posterior urethra (arrow in b). The bladder neck has a normal appearance. Radiologic Investigation of Urethral Trauma Routine baseline investigation may be helpful. Pelvic diastasis and fractures, especially if associated with sacral injuries, are suggestive of urethral injury. A distortion of the periprostatic structures or a hematoma of the ischiocavernous or obturator muscles may be seen at unenhanced CT (14), and extravasation of contrast material may be visible around the bladder base on excretory phase CT images. Similar changes are visible at intravenous urography. However, all these signs are nonspecific, and urethral injury is best demonstrated or excluded with ascending and (if feasible) descending urethrography. As described in later sections of the article, a number of modifications of the standard urethrographic technique may be necessary to achieve high-quality diagnostic images of the urethra in the presence of pelvic trauma. Selection of Patients In the acute care setting, urethral injury alone is rarely life-threatening. Before undergoing urethrography, the multitrauma patient must be hemodynamically stable. In particular, a pelvic hemorrhage due to a visceral or vascular injury must be appropriately managed before the patient undergoes urethrography. A patient with one or more clinical signs that are indicative of a high risk of urethral injury should be considered for immediate urethrography. If the urethra appears intact, a urethral catheter may be inserted. If a urethral or bladder injury is seen, a suprapubic catheter should be inserted and urethrography repeated before the patient proceeds to surgery. Patients without clinical signs indicative of urethral injury do not require immediate urethral imaging. Clinical signs in some patients referred for urethral imaging might have been overlooked initially or might have developed after a transurethral catheter was inserted. These patients require prompt urethrography, which presents a considerable technical challenge in the presence of an indwelling catheter. Urethrography at a later stage should be performed only in patients in whom a urethral injury was found at the initial imaging evaluation and was surgically corrected or bypassed with a suprapubic catheter. If at repeat urethrography the injury has healed, the catheter can be removed. A continuing leak, complete transection, or developing stricture is treated accordingly. Rarely, a patient in whom no initial clinical sign of urethral injury is noted and who does not undergo acute urethrography presents later with poor urinary flow or incontinence suggestive of either a late stricture or damage to a sphincter. Such conditions may be secondary to an overlooked injury or may be due to iatrogenic trauma that occurred during urethral catheterization. These patients also require full urethrography (Fig 7). Standard Urethrographic Technique At presentation, standard urethrography should be performed to evaluate both the anterior and posterior urethra by means of ascending (or retrograde) and descending (or antegrade) studies. At follow-up urethrography, a single (ascending or descending) study may be appropriate.

7 RG Volume 28 Number 6 Ingram et al 1637 Figures 8, 9. Images obtained with appropriate angulation of the fluoroscopic tube at ascending (8a, 9a) and descending (8b, 9b) urethrography in two male patients show a normal appearance of the urethral anatomy, the only noteworthy feature being an air bubble in the anterior urethra in one patient (arrow in 8a). For urethrography of male patients, the external meatus is prepared in sterile fashion with the patient supine. Various devices may be used to instill the contrast agent: a specially designed clamp (eg, Knutsson or Brodney), a 6 8-F Foley catheter with a 5-mL inflatable balloon, or a hysterosalpingographic catheter with a 3-mL balloon. When the catheter tip reaches the fossa navicularis, the balloon is inflated with 1 2 ml of saline solution. Anesthetic gel is not routinely used during catheter insertion because it increases the likelihood of catheter expulsion. Once the clamp or catheter has been inserted and the balloon is inflated, the fluoroscopic C-arm is rotated to a 30 left or right anterior oblique position or the patient is asked to elevate his left side to approximately the same angle. The oblique angle is essential to demonstrate the entirety of the urethra (Figs 8a, 9a). For ascending urethrography, the penis is placed laterally over the thigh, and, while moderate traction is applied, ml of an iodinated contrast agent is injected slowly via the catheter with fluoroscopic guidance. A slow rate of injection reduces the risk of extravasation. The injection should continue until the contrast material is seen to flow past the external urethral sphincter and into the bladder. Image acquisition should be initiated at this stage. Often, a spasm of the external sphincter prevents filling of the membranous and prostatic urethra. If this occurs, gentle continuous positive pressure should be applied with injection via the catheter until the sphincter relaxes. If a descending study is to be performed, the bladder may be filled with a continuous injection of ml of the contrast agent. Adequate bladder filling is important to exclude bladder trauma and to enable forceful voiding; however, pain or a pelvic hematoma may prevent the instillation of such a large volume of fluid. Male patients should be instructed to micturate into a bottle while in an oblique standing position. Images should be obtained during maximal urinary flow to show the entire length of the urethra (Figs 8b, 9b). Post-voiding views also are important for excluding subtle leaks at the bladder neck.

8 1638 October Special Issue 2008 RG Volume 28 Number 6 Figures 10, 11. Importance of tube angulation for depiction of the bladder neck at cystography. (10a) Cystogram obtained in a male patient with pelvic trauma shows a metallic surgical device, used for internal fixation of the pubic symphysis, that obscures the bladder neck. (10b) Oblique view obtained with craniocaudal angulation of the x-ray tube provides better visibility of the bladder base (arrow). (11) Cystogram obtained in a male patient who sustained a sacral fracture when he was hit by a tram shows a subtle leak that cannot be evaluated with confidence because an external fixation device obscures the bladder neck. The patient s immobility and the lack of a C-arm on the fluoroscopic imaging system prevented the acquisition of oblique views, so the injury could not be accurately classified, and cystography had to be repeated at a later date. The female urethra is more difficult to evaluate. In the nontrauma setting, micturating cystourethrography may be performed with the use of a suprapubic catheter or a dedicated doubleballoon female urethrographic catheter; however, bladder catheterization is contraindicated in cases of pelvic trauma. If a suprapubic catheter is not already in place and a voiding study therefore cannot be performed in female patients with pelvic trauma, an ascending study may be attempted by using a hysterosalpingographic catheter with the balloon pressed against or just beyond the meatus. Alternatively, a Knutsson clamp may be used with the rubber bung firmly pressed against the meatus. A complete urethrographic study requires a sufficiently mobile, cooperative patient, but a patient s movement may be hampered by pain or by a previously placed catheter or externally placed fixation device. The latter also may obscure fluoroscopic views. Moreover, a penile or pelvic hematoma may limit urethral or bladder filling. These limitations may be overcome by using the methods described in the next section. Complications after urethrography are rarely significant but can be avoided with the use of an appropriately adjusted technique (Table 3). Urethrography in the Trauma Setting In patients with pelvic trauma, complete ascending and descending urethrography should be carried out whenever possible. The most vulnerable areas the bladder neck, prostatomembranous junction, and membranous and bulbous segments should be evaluated with particular care. In a patient with polytrauma, urethrography should be performed in the fluoroscopy department by an experienced radiologist, not in the admitting department. In the ideal situation, the patient should be able to rotate and to bear enough weight to allow the use of the standard ascending and descending urethrographic technique described earlier. However, in actuality, patient movement may be inhibited by an external

9 RG Volume 28 Number 6 Ingram et al 1639 Figure 12. Bladder neck leak in a male patient with pelvic trauma. (a) Initial left anterior oblique cystogram obtained with 30 angulation of the x-ray tube does not provide a clear view of the bladder base. (b) Cystogram obtained with greater craniocaudal angulation of the x-ray tube provides better depiction of the bladder neck and leak (arrow). Table 3 Methods for Avoiding Complications of Urethrography Complication Acute urinary tract infection Adverse effect of the contrast agent Additional urethral trauma Method of Avoidance Use aseptic technique; delay urethrography if there is evidence of infection Check patient medical history for previous allergic reaction to a contrast agent; avoid intravasation by injecting the agent slowly and filling the balloon minimally Avoid urethral catheterization until ascending and descending urethrographic views have been obtained and reviewed pelvic bone fixation device, a transurethral bladder catheter, or pain. In those circumstances, the standard technique may have to be modified. Patient Positioning Most often, the patient s mobility is limited. Once positioned on the fluoroscopic table, the patient should be helped to move to a 30 left anterior oblique position. Foam cushions may be placed underneath the patient to help maintain that position and ensure that the urethra and bladder neck are depicted in optimal profile. If movement is impossible (eg, in the case of a potentially unstable spinal column injury or pelvic fracture), the tube may be rotated to a 30 left anterior oblique angulation. If the patient is unable to stand, the table may be elevated to a 45 angle during voiding, with a footrest placed to help bear the weight of the lower extremities; many patients, especially men, find it difficult to void when supine. X-ray Tube Positioning Because of the relative immobility of patients, fluoroscopic views obtained with a 30 angulation of the x-ray tube and with an empty bladder often are necessary to evaluate the bladder neck. A subtle leak from the bladder neck may not be visible unless the tube is tilted craniocaudally (Figs 10, 11). Metallic devices that are implanted surgically for fixation of the pubic symphysis may obscure the base of the bladder. In such cases, steep craniocaudal obliquity is essential to allow an unobstructed view of the bladder base, the junction of the prostatic and membranous urethra, and the membranous urethra proper (Fig 12). Pericatheter Urethrography If a transurethral catheter was previously placed, it must be left in position until urethral integrity has been evaluated. In this case, a pericatheter technique must be used for urethrography. Ascending pericatheter urethrography may be performed in one of two ways: With the first method, a small-gauge (4 6-F) pediatric catheter is inserted alongside the indwelling catheter into the navicular fossa, the balloon on the pediatric catheter is inflated, and the contrast agent is Teaching Point

10 1640 October Special Issue 2008 RG Volume 28 Number 6 Figure 13. Ascending pericatheter urethrography performed by inserting a small-gauge balloon-tipped catheter (white arrow) alongside an indwelling bladder catheter (black arrow) in a male patient after pelvic trauma. Inflation of the smaller catheter balloon in the fossa navicularis created a sufficient seal to achieve good urethral distention, and the urethra is reliably seen to be intact. Figure 14. Ascending pericatheter urethrography performed by gently instilling contrast material through a narrow-gauge feeding tube while gradually advancing it alongside an indwelling catheter (arrows) in a male patient after pelvic trauma. The entire urethra is opacified with this method, but a small leak might be missed because the urethra is not as well distended as with the method shown in Figure 13. Figure 15. Descending pericatheter urethrography in a male patient with an indwelling catheter after pelvic trauma. (a) Image obtained with the catheter balloon inflated does not depict the urethra because the patient was unable to micturate. (b) Image obtained during voiding, after the balloon was deflated, shows an intact urethra. instilled through the pediatric catheter (Fig 13). Alternatively, a small-bore (4 6-F) feeding tube may be inserted alongside the indwelling catheter. Since no seal is created with the latter method, only a part of the urethra may be visible, because of leakage after instillation of the contrast agent. With continuous instillation of the contrast agent as the tube is advanced along the urethra, opacification of the entire urethra can be achieved (Fig 14). However, this method provides a nondistended urethral view. If a distended view is needed to ensure that a small defect is not missed, a seal may be created by tightly tying a length of ribbon gauze around the penis, proximal to the glans, with the feeding tube tip above the tie. Descending pericatheter urethrography is performed while the patient attempts to void around the indwelling catheter after removal of the pediatric catheter. Often, voiding cannot be

11 RG Volume 28 Number 6 Ingram et al 1641 Figure 16. Importance of performing both ascending and descending urethrography to exclude injury after pelvic trauma. (a) Ascending pericatheter urethrogram appears normal. (b) Descending pericatheter urethrogram shows a large extraperitoneal leak (arrow) surrounding the bladder neck and posterior urethra. The catheter, with the balloon still inflated, was advanced farther into the bladder to allow voiding for the descending study. When this method is used instead of balloon deflation, the catheter cannot be expelled during voiding. Figure 17. Comparison of descending urethrograms obtained with (a) and without (b) an indwelling catheter in a male patient with a superior pubic ramus fracture. In the initial study, which was performed with the indwelling catheter advanced farther into the bladder, the balloon deflated, and the external part of the catheter (arrow in a) taped to the penis to prevent expulsion during voiding, no urethral leak was visible. In the repeat study, which was performed after withdrawal of the indwelling catheter, there was likewise no evidence of a urethral leak or stricture. achieved unless the balloon at the catheter tip is pushed into the dome of the bladder or deflated (Fig 15). Especially after balloon deflation, care must be taken to avoid expulsion of the catheter. To decrease the likelihood of expulsion, the indwelling catheter should be advanced farther into the bladder, and its external part should be taped firmly to the tip of the penis. Voiding studies may be performed with the patient in the supine position, if the patient is unable to stand or tolerate a feet-down table tilt. Supine voiding is difficult for most men, but a sufficient bladder instillation ( ml) and the sound of running water in the background may be helpful. Both ascending and descending studies are essential to exclude a leak (Fig 16). If the appearance of the urethra is normal at both ascending and descending pericatheter urethrography, the indwelling catheter may be removed and a second descending study may be performed with the standard urethrographic technique (Fig 17).

12 1642 October Special Issue 2008 RG Volume 28 Number 6 Figure 18. Use of simultaneous ascending and descending urethrography to determine the length of a complete urethral transection (Goldman type V injury) in a male patient. (a) Image from initial ascending urethrography shows a complete transection of the anterior urethra (arrow) but does not allow estimation of the length of the defect. (b) Image from simultaneous ascending and descending urethrography, performed with the balloon catheter still in place in the distal urethra to maintain distention below the level of transection and with voiding via the posterior urethra, clearly depicts the length of the defect (arrow). Teaching Point Imaging of Urethral Transection If a complete urethral transection is observed on an initial ascending urethrogram, it is important that the length of the defect be accurately determined, because a long defect requires more extensive urethroplasty. The length of the defect can be elegantly shown by performing simultaneous ascending and descending studies. At ascending urethrography, when the anterior urethra is well distended up to the level of the transection, the catheter is blocked and taped to the side of the thigh. Next, the contrast agent for the descending study is instilled via a suprapubic bladder catheter, and the patient voids, ideally filling the posterior urethra. With both the patient and the x-ray tube positioned at appropriate angles, the length of the defect should be clearly visible (Fig 18). Imaging of the Female Urethra It is more difficult to assess the integrity of the female urethra, which is shorter than the male urethra. For urethrography in female patients, the bladder is filled with the contrast agent via a suprapubic catheter. A descending study alone often suffices (Fig 19). Views obtained after complete voiding are particularly important for excluding subtle leaks from the bladder neck. If ascending urethrography is essential, the techniques described earlier (see the section Standard Urethrographic Technique ) may be used. Summary Urethral injury should be suspected and excluded in patients with pelvic fractures, especially if high-risk clinical signs are present. Complete urethrography helps identify or exclude urethral injuries, allows their accurate classification with the Goldman or the AAST classification system, and facilitates treatment planning. Both ascend-

13 RG Volume 28 Number 6 Ingram et al 1643 Figure 19. Descending urethrography in a female patient with an indwelling urethral catheter after pelvic trauma. (a) Initial image shows filling of the bladder with a contrast agent via a suprapubic catheter. (b) Image obtained after voiding depicts no leak. ing and descending studies should be carried out with appropriate technical modifications. In particular, the technique should be tailored to the patient s condition, with attention given to proper patient positioning, tube angulation, adequate bladder filling, and pericatheter injection. References 1. Koraitim MM. Pelvic fracture urethral injuries: evaluation of various methods of management. J Urol 1996;156: Eaton J, Richenberg J. Imaging of the urethra: current status. Imaging 2005;17: Ku JH, Kim ME, Jeon YS, Lee NK, Park YH. Management of bulbous urethral disruption by blunt external trauma: the sooner, the better? Urology 2002;60: Patel U, Rickards D. The normal urethra (Figure 9.1). In: Patel U, Rickards D, eds. Imaging and urodynamics of the lower urinary tract. London, England: Taylor & Francis, 2005; Patel U. Lower urinary tract trauma. In: Patel U, Rickards D, eds. Imaging and urodynamics of the lower urinary tract. London, England: Taylor & Francis, 2005; Goldman SM, Sandler CM, Corriere JN Jr, et al. Blunt urethral trauma: a unified, anatomical mechanical classification. J Urol 1997;157: Patil U, Nesbitt R, Meyer R. Genitourinary tract injuries due to fracture of the pelvis in females: se- quelae and their management. Br J Urol 1982;54: Perry MO, Husmann DA. Urethral injuries in female subjects following pelvic fractures. J Urol 1992;147: Kommu SS, Illahi I, Mumtaz F. Patterns of urethral injury and immediate management. Curr Opin Urol 2007;17: Kawashima A, Sandler CM, Wasserman NF, LeRoy AJ, King BF, Goldman SM. Imaging of urethral disease: a pictorial review. RadioGraphics 2004;24(suppl 1):S195 S Moore EE, Cogbill TH, Malagoni MA, et al. Organ injury scaling. Surg Clin North Am 1995;75: Colapinto V, McCollum RW. Injury to the male posterior urethra in fractured pelvis: a new classification. J Urol 1977;118: Brandes S. Initial management of anterior and posterior urethral injuries. Urol Clin North Am 2006; 33: Ali M, Safriel Y, Sclafani SJ, Schulze R. CT signs of urethral injury. RadioGraphics 2003;23: This article meets the criteria for 1.0 AMA PRA Category 1 Credit TM. To obtain credit, see /rg_cme.html.

14 RG Volume 28 Volume 6 October 2008 Ingram et al Urethral Injuries after Pelvic Trauma: Evaluation with Urethrography Mark D. Ingram, MA, MBBS, et al RadioGraphics 2008; 28: Published online /rg Content Codes: Page 1632 Urethral injury is a common complication of pelvic trauma; it occurs in as many as 24% of adults with pelvic fractures. Page 1632 The most common injury by far is that of the posterior urethra. Such injury occurs in 3% 25% of patients with pelvic fractures. Page 1634 The more widely accepted, unified classification system proposed by Goldman and colleagues emphasizes the anatomic location of an injury (eg, according to whether it is nearer to the urogenital diaphragm or the external sphincter). This system includes a category for bladder injuries that involve or simulate posterior urethral injury (Table 2). Page 1639 Because of the relative immobility of patients, fluoroscopic views obtained with a 30-degree angulation of the x-ray tube and with an empty bladder often are necessary to evaluate the bladder neck. A subtle leak from the bladder neck may not be visible unless the tube is tilted craniocaudally. Page 1642 If a complete urethral transection is observed on an initial ascending urethrogram, it is important that the length of the defect be accurately determined, because a long defect requires more extensive urethroplasty. The length of the defect can be elegantly shown by performing simultaneous ascending and descending studies. At ascending urethrography, when the anterior urethra is well distended up to the level of the transection, the catheter is blocked and taped to the side of the thigh. Next, the contrast agent for the descending study is instilled via a suprapubic bladder catheter, and the patient voids, ideally filling the posterior urethra. With both the patient and the x-ray tube positioned at appropriate angles, the length of the defect should be clearly visible.

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