21. Surgical Reconstruction of Pelvic Fracture Urethral Injury
KeywordsPelvic fracturePFUIPFUDDPosterior urethral strictures
Posterior Urethral injuries after Pelvic Fracture are one of the most devastating and debilitating situations in Urology. It represents a real surgical and decision-making challenge. The adequate initial and late management to this problem with a multidisciplinary approach could avoid many possible urosexual and orthopedic complications, offering the best results to these patients.
The incidence of Posterior urethral injury varied from 3% to 25% average 9.9% of Pelvic Fractures [1, 2]. The mean age of presentation is 33-year-men in the majority of series reported [3–5], Other causes less common are described like gunshot injuries and explosive blasts , Female urethral injuries due to pelvic fracture are very rare 0.7% reported in large series .
Different Mechanism of urethral injury have been proposed, these include Crush, laceration, avulsion and distraction. In some severe cases the bladder, bladder neck, rectum could be damage too. The pubic ramus and ischium can act as “switch-blade” and lacerate or disrupt the urethra, other explanations propose a shearing force which leads to disruption of the membranous urethra from the apex of the prostate .
The etiology, severity and management of posterior urethral injury is related according to demographic location. In developed countries, the most common etiology is motor vehicle accidents. Morey et al. reported 40% associated car to pedestrian, car to motorcycle 26% and falling down and crash injuries in 26% .
In developing countries pedestrian (35%), motorcycle (26.5%), bicycle (12.8%) accidents are more common. Nevertheless, the severity and complexity of these injuries increases in the developing countries and seems to be related to the initial management. In developing countries, the primary treatment is given by general surgeon in comparison with developed countries that are given by a urologist . Other causes less common are described like gunshot injuries and explosive blasts .
21.4 Mechanism of Injury
The true anatomical pelvis is composed by the pubic arch and symphysis pubis in the anterior part, the iliac bones lateral, the sacrum and the sacroiliac joints in the posterior. Pelvic fractures may be classified in stable or unstable .
Pelvic fractures may also be classified according to the direction of the force injury. The major forces are anteroposterior compression, lateral compression with or without rotation and vertical shear. Anteroposterior and lateral compression fractures may be associated with stable or unstable hemi pelvis but vertical shear fractures are grossly unstable .
The puboprostatic ligaments and the perineal membrane are critical in the injury mechanism of the lower urinary tract, as they share an attachment with both, the anterior pelvic ring might therefore apply traction to the urethra. There are four attachments, as either the right or left hemipelvis and in some cases both sides are displaced. The pattern of ligament damage depends of the direction and velocity of the trauma forces. Recently we know that the majority of injuries occur at the junction of the membranous urethra and the bulbar urethra, leaving the urethral sphincter mechanism intact.
There are three types of urethral injury: contusions, partial ruptures and complete ruptures.
An injury that has incompletely ruptured part of the circumference of the urethra is a contusion, in this cases healing is possible without stricture formation. An injury that has completely ruptured part of the circumference of the urethra is a partial injury. And a complete rupture is when the injury has completely rupture the entire circumference of the urethra. In these cases, the stricture formation is inevitable.
21.5 Initial Management
The initial management is focused in stabilization of the patient based in the trauma protocols. A multidisciplinary approach must be done. Once the patient is stable we can make immediate management of PFUDD with endoscopic realignment (early or delayed) or cystostomy with delayed repair. Each approach must be evaluated carefully depending the patient condition, mechanism, severity of trauma and kind of urethral damage.
The aim of early realignment is to better align the proximal urethra and the distal stump to minimize stricture or defect. The recent progress of endourological techniques make more feasible a successful alienation. Several studies justified this approach because it could give a chance to the patients to avoid a future surgery and if this failed, the surgery becomes more easy and surgical approach less aggressive. The disadvantage of this approach is the association with erectile dysfunction and incontinence. Other complication has been reported as false passages, bladder neck injury, infection, cavities, anterior urethral damage and others. This support that initial cystostomy with delayed repair is safer, less blood loss, simple approach and lower the resulting rates of impotence and incontinence .
Other associated injuries may be present in this patients that requires immediate surgical open repair. Intraperitoneal bladder rupture, rectal injuries (rarely reported 3%) and bladder neck and prostate injuries. Rectal injury is frequently associated with concurrent bladder neck lacerations . Bladder neck injuries are more common in children cause is more vulnerable, in adults the typical injury occur in the midline of both the bladder neck and prostatic urethra in association with lateral compression fracture of the pelvis or an open – book injury .
This condition must be repaired immediately trying to restore an acceptable degree of continence. Other rare associated injuries have been described like sequestered prostate and blow out of the prostate .
21.6 Clinical Findings
Clinical diagnosis of urethral injury in PFUDD must be suspected by history and nature of trauma. Patient with vehicle accident, pedestrian accident, motor vehicle accident or fall from height with inability to void, blood in the urethral meatus, perineal hematoma (butterfly shape). Physical examination may reveal malrotation of the hemi pelvis and compression of the iliac crest will indicate pelvic instability. Shortening of the extremity could be secondary to displaced pelvic ring. Abdominal examination is important to identify full bladder cause urine retention but and hematoma or intraperitoneal bleeding could mask a full bladder. Inspection of the anus is mandatory, elevated prostate is difficult to palpate in young patients so the main goal of digital examination is to exclude rectal injury. The absence of these signs does not exclude the presence of urethral injury.
So, the urethrogram is the cornerstone of diagnosis in these situations .
21.7 Preoperative Evaluation
Actually, the most widespread and gold standard image diagnostic method for PFUDD is the combined dynamic retrograde urethrography (RUG) and voiding cystourethrography (VCUG) , these asses the continuity of urethra, site, severity and length of urethral injuries, bladder neck competence (open or closed) state of the bladder (Capacity, ureteral reflux, stones, diverticulum, fistula). This study could be done when we suspected clinically urethral injury in the acute phase of pelvic trauma and the patient is stable. But is usually done within a week of injury or if we are planning a delayed primary repair is done after 3 months.
Type 1. The prostate or the urogenital diaphragm is dislocated, causing elongation and tension of the bulbomembranous urethra. There may be urethral contusion or laceration.
Type 2. The membranous urethra is ruptured above the urogenital diaphragm, with or without prostatic injury. The bulbar urethra is intact. The rupture must be partial or complete.
Type 3. The membranous urethra is disrupted above and below the urogenital diaphragm. The rupture usually is complete and may be associated with rupture of the urogenital diaphragm and or rupture of the bulbar urethra.
Recently Goldman et al. proposed a new anatomically based classification to compare the treatment options and outcomes of each kind of injury .
184.108.40.206 Goldman Classification
Posterior urethra stretched but intact.
Tear of the prostatomembranous urethra above the urogenital diaphragm.
Partial or complete tear of both anterior and posterior urethra with disruption of the urogenital diaphragm.
Bladder injury extending into the urethra, Iva Injury of the Bladder base with periurethral extravasation simulating posterior urethral injury.
Partial or complete pure anterior urethral injury.
Koraitim proposed that the surgical approach needed not only depends on the urethral defect. But also on the length of bulbar urethra, so he proposed the urethrometry index or gapometry which is calculated by dividing the length of the urethral defect by the length of the bulbar urethra (from the proximal urethra to the penoscrotal junction) Fig. () an index <0.35 predicted simple perineal approach and index >0.35 predicted progressive perineal maneuvers . The disadvantage is that this index could be modified if the X ray is not correctly done .
A plain X-Ray is done at the beginning to evaluate healing fracture of the pelvis, an exclude possible stones in the bladder. The RUG and downogram must be performed by the treating urologist using fluoroscopy. This is a dynamic study so we can evaluate urethral distensibility, bladder capacity, bladder neck function and other situations.
We suggest start with alfa blockers 2 days before the study for promote bladder neck opening for better evaluation of the posterior urethra. we start by filling the bladder through the suprapubic tube with contrast added to 500 cc of saline solution, the instillation must be slow until the bladder is full. Then the genital area is prepared with povidone iodine. The patient is placed in an oblique position and contrast injected gently through the urethra. This will show us the gap between proximal and distal ends of the urethra (Fig).
Sometimes the bladder neck does not open even alfa blockers are administrated before. In this situation, we can combine fluoroscopic evaluation with RUG plus.
Flexible anterograde scope from suprapubic tract. This is very useful cause we can evaluate under vision adequate bladder neck integrity, prostatic urethra and if the injury involves the membranous urethra or the mechanism of the distal sphincter is preserved  the fluoroscopy plus flexible scope give us too accurate evaluation of the proximal gap (Fig).
The adequate image assessment of the PFUDD can predict which surgical approach will be required .
21.9 Penile Doppler Ultrasound
Erectile dysfunction is a common sequel of pelvic fracture particularly those associated with posterior urethral injury when it can be neurogenic or arteriogenic due to damage of the cavernous nerves or branches of the pudendal arteries. The incidence of ED in PFUDD patients range between (27.5–73%) .
Penile Duplex Doppler ultrasound had documented in patients with PFUDD that 48.7% of this had arterial ED, 14.6% Venous Leak and 36.5% had non-vascular ED most likely to neurogenic etiology .
A multivariate analysis documented that diastasis of the pubic symphysis, lateral prostatic displacement, and a long urethral gap at surgery are predictors of ED .
Doppler duplex penile ultrasound with intracavernous injection (0.1 ml Trimix) are suggested in all patients with PFUDD. Systolic velocity < 25 ml/seg, rise time > 80 mseg or both suggest arteriogenic ED. Jordan G et al. reported high risk of isquemic bulbar necrosis after urethral reconstruction in these patients so they suggest primary penile revascularization previous to definitive urethroplasty improving the quality of erections and outcomes in urethroplasty .
21.10 CT Scan
Patient with acute trauma is initially resuscitated in the ER, as part of the initial evaluation the CT scan one of the most used diagnostic methods. That means that in patients with PFUDD CT is made before any urethral evaluation. Currently Tomography in not used commonly for this situation but some CT findings can give us information about the injury of posterior urethra. These findings include obscuration of the urogenital diaphragmatic fat plane, hematoma of the ischiocavernosus and obturator internus muscles and the prostatic contour , and obscuration of the bulbocavernosus muscle .
21.11 Magnetic Resonance Imaging
MRI is not the first option to evaluate patients with PFUDD but it could be used in complex injuries and REDO cases. This could provide useful information for planning the correct surgical approach in these patients. It correctly estimates the length of the gap, prostatic displacement, delineates the site and density of the scar tissue, reveals the presence of false passages and other associated injuries to repair. Recently has Joshi has proposed new protocol of MRI techniques that result much clear and useful for surgery planning . Based on the same principle Joshi and Kulkarni now make 3 D Printed models of PFUDD which was presented at AUA meeting.
21.12 Operative Steps
21.12.1 Position and Preparation
Simple lithotomy position is needed, this is enough to give us an adequate exposure. Some surgeons prefer exaggerated lithotomy, but the risk neurovascular complications increase. The patient should have antithrombotic stockings and intermittent pneumatic compression leggings. Allen yellowfin stirrups are the best for any kind of perineal surgery.
The skin is prepared with Chlorhexidine or betadine solution from the umbilicus down to the mid thigh and the patient draped to expose the perineum and the suprapubic area around any suprapubic catheter site or in case Access to the suprapubic area is required if abdominoperineal approach is needed in more complex patients. Prophylactic antibiotics are given intravenously with anesthesia or some days before if the preoperative cultures are positive.