Evaluation of Pelvic Fracture Trauma Associated Urethral Injuries
Pelvic bone fractures from motor vehicle trauma or crush injuries can be associated with urethral tears or disruptions. Often, the urethra is completely transected or torn, usually in the area of the membranous urethra, and the ends separate (generally from 1-4 cm). In general, patients are transported by ambulance to the nearest Emergency Room and are found to have blood at the tip of the urethra. Appropriate evaluation is with a retrograde urethrogram (RUG) and this confirms the diagnosis.
Imaging Showing Extravasation
These patients are completely unable to urinate, and often have suprapubic tubes placed on an emergency basis after the injury. A suprapubic tube is a catheter that enters the bladder directly through the lower midline abdomen, and allows the urine to drain through the tube into a collection bag.
Suprapubic (SP) tube
Example of antegrade and retrograde imaging (above).
As contrast is instilled, the prostatic urethra fills up to the point of blockage, and the bladder is backfilled. The gap between the two ends can be measured, and the above study will allow the exact length and location of the defect to be determined.
We are occasionally asked why we do not just fill the bladder with contrast using the suprapubic tube to obtain the imaging from above. The reason is that when a patient is not urinating, a normal bladder neck is closed at rest. Therefore, as shown, only the bladder will be filled and the normal prostatic urethra will not be seen.
Those patients who suffer traumatic urethral injuries often have associated vascular and nerve damage affecting the penis and urethra, and over half suffer erectile dysfunction as a result of the injury. We evaluate the vascular status prior to urethral reconstruction using an ultrasound test called a Penile Duplex. Most patients, even with some arterial compromise, have enough blood flow to have their urethras repaired without concern about proper healing. This test confirms adequate blood supply to the urethra. Occasionally, we document severe impairment, and in these cases, perform a revascularization procedure prior to urethral reconstruction so that the urethra will then have adequate blood supply at the time of repair.
Our patients are admitted to the hospital the day prior to surgery to receive intravenous (IV) culture specific antibiotics. This is done because when patients have suprapubic tubes, the urine is generally contaminated with bacteria, and we want to take every precaution to prevent a wound infection and an associated breakdown of the repair. Although some may consider this “overkill”, we have seen patients who were not managed according to our protocol and suffered this devastating complication, and we have performed hundreds of perineal proximal reconstructive surgeries to date without ever having an infection related failure.
The surgery to repair the urethra, also called posterior urethroplasty or urethral reconstruction, is performed in the lithotomy position. An incision is made under the scrotum, and the urethra is identified and dissected free of surrounding tissues. The urethra is then transected at the distal point of the obliteration. At that point, very hard scar tissue is encountered, and the objective is to excise the scar until the healthy normal urethra is encountered on the other side of the scar. This requires guidance so that the dissection proceeds in the proper direction towards the normal urethra and not towards the rectum, the bladder, or other structures.
A common technique to provide this guidance of the dissection is to remove the suprapubic tube and place a solid “U” shaped instrument though the established tract between the skin and the bladder, and advance the sound though the bladder neck into the posterior urethra until the scar prevents further advancement.
In the past, when the impulse of the tip of the sound was not palpable in the perineum, and in patients who had laterally placed suprapubic tubes, temporary vesicostomy was required to insure the sound was being properly directed through the bladder neck. A temporary vesicostomy is a major surgical procedure involving a large skin and bladder incision. Sutures are then used to connect the bladder to the skin, allowing the surgeon’s fingers to be placed in the bladder to guide the sound.
In an effort to avoid the occasional need to create a temporary vesicostomy and to insure a proper and safe scar excision, Dr. Gelman developed a visualizing “U” shaped hollow metal sound (provided by the J. Hugh Knight Instrument Company). In comparison to the solid sound, the new sound allows placement of a 16 French flexible cystoscope through the sound (figure 8). The tip of the sound is then directed to the obliteration under direct vision, and temporary vesicostomy has never been required since Dr. Gelman developed this instrument 11 years ago.
Picture of sound with and without scope:
Posterior urethral reconstruction is a very difficult surgery. However, these injuries are amenable to repair with a very high success rate when properly performed. Our patients are maintained with urethral catheters and suprapubic tubes for 3 weeks after surgery, and then return for imaging. In general, at that time, both tubes are then removed, and our patients resume normal urination without the need for further intervention.View Posterior Urethral Disruption Patient Video