Urethral Injuries

Anatomy Relevant to Injury

• Posterior urethra: prostatic + membranous urethra (in males); the entire short urethra in females
• Anterior urethra: bulbar + penile (pendulous) + fossa navicularis

Classification

Goldman & Sandler Classification (most widely used)

Types by Mechanism

1. Posterior Urethral Injuries (Pelvic Fracture Urethral Injury - PFUI)

• Occurs in ~10% of male patients and ~6% of female patients with pelvic fractures
• Girls <17 years have higher risk than adult women (more compressible pelvic bones)
• Most common mechanism: high-velocity blunt trauma (MVA, falls, industrial accidents)
• Straddle fractures (all four pubic rami) and fractures causing vertical/rotational instability carry the highest risk

• Shearing forces disrupt the urethra at the bulbomembranous junction
• The proximal urethra is anchored by the prostate; the distal by the perineal membrane - making the junction between them the weakest link
• In children, injury may extend more proximally to the bladder neck because of the rudimentary prostate

• Blood at the urethral meatus
• Inability to void (acute urinary retention)
• Palpably full bladder
• Additional signs: "high-riding" prostate on DRE (often unreliable due to pelvic hematoma obscuring the prostate), perineal/scrotal hematoma
• Female patients: vulvar edema, blood at vaginal introitus - careful vaginal exam is mandatory
• Caution: These signs are frequently absent or difficult to detect. Up to 23% of urethral injuries are missed at initial assessment - always check catheter position on CT

2. Anterior Urethral Injuries (Bulbar Urethra)

• "Straddle injuries" - the bulbous urethra is crushed between an impacting object and the inferior surface of the pubic symphysis
• Also: iatrogenic (instrumentation, catheterization), penetrating trauma
• Perineal hematoma may extend in the "butterfly" distribution (bounded by Colles' fascia)

• Incidence: 3.2-6.7 injuries per 1000 male patients catheterized
• Complications of Clavien-Dindo grade 2 or higher occur in up to 81% of affected men
• Risk factors: urethral stricture disease, BPH, prior surgery or pelvic radiation, operator inexperience
• Injuries often result from inadvertent balloon inflation in the urethra
• Female pelvic reconstructive surgery can also produce urethral injury, often concurrent with bladder or ureteral injury

Diagnosis

Retrograde Urethrogram (RUG) - Gold Standard

1. Place a 16-Fr urethral catheter (unlubricated) 1 cm into the fossa navicularis
2. Inflate balloon with 3 mL water for a snug fit (alternatives: Brodney clamp or gauze traction)
3. Position patient oblique or lateral decubitus
4. Inject 25 mL of low-osmolality contrast medium (200-300 mg iodine/mL) under fluoroscopy
5. Ideally performed under fluoroscopy; oblique radiographs are an alternative

• Contrast extravasation outside the posterior urethra = PFUI confirmed
• If contrast reaches the bladder = partial disruption
• No bladder opacification = complete disruption

Other Imaging

• CT cystography: useful when a standard Foley has been misplaced in an unrecognized urethral injury
• MRI: provides accurate grading and assessment of complications (fibrosis extent, sphincter integrity)
• Urethral ultrasound: more accurate than retrograde urography for stricture length assessment; highly operator-dependent
• VCUG (voiding cystourethrogram): used alongside RUG for preoperative planning in delayed reconstruction

Management

Acute Management of PFUI

• Can be placed quickly in unstable patients
• Provides long-term diversion while awaiting reconstruction (3-6 months)
• Allows access if primary realignment is later planned
• Ultrasound guidance or open placement recommended if bladder is displaced by pelvic hematoma
• Can be placed even if ORIF of pelvic fracture is planned - no evidence of increased hardware infection risk

• Best performed within the first week, with two urologists using cystoscopy and fluoroscopy
• Catheter maintained for 4-6 weeks post-realignment
• Pericatheter RUG or VCUG performed at time of catheter removal
• Evidence is conflicting: most patients still develop strictures, but these tend to be less complex and more easily treated than in SPT patients
• Rates of erectile dysfunction and incontinence are similar between SPT and primary realignment

Delayed Reconstruction (Definitive Treatment)

• Planned 3-6 months after injury when pelvic hematoma has resolved
• Pre-operative imaging: RUG + VCUG to define site and length of obliterated segment; urethral ultrasound optional
• Posterior urethroplasty (excision + primary anastomosis) = treatment of choice for urethral distraction injuries
• Anastomotic urethroplasty = treatment of choice for straddle injury-related anterior urethral strictures - success rate >95%, as the scar is typically 1.5-2 cm and allows tension-free end-to-end anastomosis
• Endoscopic incision of a completely obliterated urethra is ineffective and should be avoided
• Repeated endoscopic dilation is neither clinically effective nor cost-effective, and leads to more complex reconstruction needs

Complications

Anterior vs. Posterior Urethral Injury - Quick Comparison

Key Points Summary

1. Suspect urethral injury in any pelvic fracture - found in ~10% of significant pelvic fractures
2. The classic triad: blood at meatus + inability to void + palpable bladder - but often incomplete
3. RUG before catheterization in all suspected urethral injuries
4. SPT is the AUA-preferred initial treatment for most PFUI
5. Primary surgical repair is not recommended for PFUI (except bladder neck/rectal injury concurrence)
6. Definitive repair is posterior urethroplasty - delayed 3-6 months
7. Stricture formation is near-universal after PFUI regardless of initial management approach
8. Female PFUI is rare but requires early primary repair

Recent evidence note: A 2024 meta-analysis (PMID 39084035) on primary endoscopic realignment vs. delayed urethroplasty in children with PFUI found the evidence quality remains poor, consistent with the textbook acknowledgment that the literature is conflicting on this question.