15.3 Genitourinary Trauma: Kidney, Bladder & Urethra

Genitourinary Trauma: Kidney, Bladder & Urethra

Genitourinary injuries occur in roughly 10% of all major trauma patients. Urological management must be seamlessly integrated into the primary and secondary surveys of the Advanced Trauma Life Support (ATLS) framework. Hemodynamic stability, resuscitation of life-threatening injuries (airway, tension pneumothorax, massive intra-abdominal hemorrhage), and damage control surgery take absolute precedence over urological reconstruction.

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Renal Trauma

The kidneys are the most frequently injured genitourinary organs, with blunt trauma (motor vehicle collisions, falls, sports impacts) accounting for 80% to 90% of cases in Europe, and penetrating trauma (gunshot, stab wounds) comprising 10% to 20%.

Indications for Radiological Staging

Radiological imaging is not required for every patient with minor hematuria. According to EAU Trauma Guidelines, multiphase Contrast-Enhanced Computed Tomography (CECT) of the abdomen and pelvis is indicated in a stable patient under the following criteria; instability may require intervention before CT:

1. All blunt trauma patients presenting with macroscopic (gross) hematuria.
2. All blunt trauma patients presenting with microscopic hematuria AND a documented episode of hypotension (systolic blood pressure $< 90 \text{ mmHg}$) at any time during initial evaluation or resuscitation.
3. Patients with a history of high-energy rapid deceleration injury (e.g., high-speed motor vehicle collision, a significant fall), even in the complete absence of hematuria (due to risk of main renal artery intimal tear or avulsion).
4. All patients with penetrating trauma to the abdomen, flank, back, or lower thorax, irrespective of the degree of hematuria. Clinical signs such as flank bruising/tenderness, fractured ribs or an abdominal mass also justify renal imaging.

Multiphasic CT Protocol

Ideally assess the kidneys with arterial, nephrographic and excretory phases; actual trauma protocols vary:

• Arterial Phase: Evaluates vascular integrity, identifies active contrast extravasation ("contrast blush"), pseudoaneurysms, and arteriovenous fistulas.
• Nephrographic Phase (70–90 seconds post-contrast): Maximally enhances the renal parenchyma; delineates cortical lacerations, depth of injury, and non-perfused devitalized segments.
• Delayed Excretory Phase: Images at about 5 minutes or later (often 10–15 minutes when needed) assess collecting-system/ureteric injury. Hypovolaemia may delay excretion. Add or repeat delayed images if the initial trauma CT has not adequately evaluated a suspected leak.

AAST Renal Injury Grading (2018 Revision)

The following is the 2018 scale reproduced in EAU 2026. AAST published a further 2025 revision; specify the version when interpreting a grade, rather than mixing criteria from the two scales.

2018 AAST RENAL INJURY SCALE
I   Contusion or subcapsular haematoma; no parenchymal laceration.
II  Perirenal haematoma confined to Gerota's fascia, or laceration
    <=1 cm deep without urinary extravasation.
III Laceration >1 cm without collecting-system rupture; also kidney
    vascular injury or active bleeding contained within Gerota's fascia.
IV  Collecting-system laceration with urinary extravasation, renal-pelvis
    laceration or complete UPJ disruption; segmental artery/vein injury;
    bleeding beyond Gerota's fascia; segmental or complete infarction
    due to thrombosis WITHOUT active bleeding.
V   Shattered kidney with loss of identifiable anatomy; main renal
    artery/vein laceration or hilar avulsion; devascularisation WITH
    active bleeding.
Advance one grade for bilateral injuries, up to grade III.

Management Principles: NOM, Endovascular, and Surgery

• Non-Operative Management (NOM):
  • The usual approach for stable blunt injuries, including grades I–III, most grade IV and selected grade V injuries. Consider associated injuries, mechanism, imaging and available rescue interventions.
  • Includes initial activity restriction, observation and serial haemoglobin/haematocrit tailored to severity. Mobilise when clinically appropriate; prolonged strict bed rest adds thrombosis risk. Antibiotics follow actual injury/intervention indications and local stewardship, rather than routine broad-spectrum courses. Repeat imaging for deterioration and in high-grade or penetrating injury, usually at 2–4 days.
• Endovascular Intervention (Transcatheter Arterial Embolization - TAE):
  • Indicated for hemodynamically stable or stabilized patients exhibiting active arterial contrast extravasation ("contrast blush") on CT, expanding retroperitoneal hematoma, or post-traumatic pseudoaneurysm / AV fistula.
  • Superselective coils, particles or gelatin agents can control bleeding while preserving uninvolved parenchyma. Success varies with injury severity; repeat embolisation or surgery may be needed.
• Urinary Extravasation Management:
  • Isolated urinary extravasation from a collecting system breach (Grade IV) in a stable patient does not require immediate open surgery.
  • Initial observation is appropriate for an otherwise well patient; many leaks resolve without intervention.
  • If extravasation persists, or if the patient develops persistent flank pain, high fever, or an infected urinoma, retrograde Double-J ureteral stenting (along with a urethral Foley catheter) decompresses the collecting system and promotes closure.
• Indications for Surgical Exploration:
  • Absolute Indications: Refractory hemodynamic instability unresponsive to aggressive blood/fluid resuscitation; expanding, pulsatile, or uncontained retroperitoneal hematoma discovered during emergency laparotomy for associated visceral injuries; or major bleeding vascular injury requiring operative control. A stable unilateral arterial occlusion without bleeding is a different situation and does not automatically require exploration.
  • Surgical Principles: Transperitoneal approach. Obtain vascular control and preserve a contained haematoma until control is feasible; do not open a stable perirenal haematoma merely because it is encountered at laparotomy. Renal salvage depends on bleeding control, viable tissue and associated injuries. Renorrhaphy, partial nephrectomy, or total nephrectomy is performed based on tissue viability.

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Bladder Trauma

Bladder injuries occur in roughly 1.5% of all blunt abdominal trauma admissions, strongly associated with severe pelvic ring fractures (up to 85% of bladder ruptures occur alongside pelvic fractures).

Mechanism and Classification

• Extraperitoneal Rupture:
  • Typically caused by pelvic ring fractures (especially pubic rami fractures and symphyseal diastasis) that shear or lacerate the anterolateral bladder base, or direct puncture by displaced bone fragments.
  • Contrast extravasates into the perivesical retropubic space (space of Retzius) and pelvic fascial planes.
• Intraperitoneal Rupture:
  • Results from a sudden direct blow or compressive seatbelt impact over a distended, full bladder.
  • The dome of the bladder—which is covered by peritoneum, lacks bony support, and represents the thinnest, most mobile segment—bursts under hydraulic pressure.
  • Urine and contrast escape freely into the peritoneal cavity.

Diagnostic Technique: CT Cystography vs. Conventional Cystography

Passive bladder filling during intravenous contrast excretion, even with a clamped catheter, does not adequately exclude rupture. Perform active retrograde cystography when bladder injury is suspected.

• Gold Standard: Retrograde CT Cystography (or standard fluoroscopic retrograde cystogram):
  • Dilute water-soluble contrast (e.g., at least 300–350 mL in adults; age/size-appropriate paediatric filling under the imaging protocol) must be instilled into the bladder retrogradely under gravity pressure (from a height of 40–50 cm) until flow stops or active patient resistance occurs.
  • Post-drainage washout views are critical to detect extravasation obscured behind a contrast-filled bladder.

Contrast Extravasation Patterns:
Extraperitoneal: Flame-shaped, localized contrast confined to pelvic fascial planes.
Intraperitoneal:  Free contrast outlining bowel loops, mesentery, and tracking into paracolic gutters.

Treatment Protocols

• Extraperitoneal Rupture Management:
  • Standard treatment for an uncomplicated blunt extraperitoneal rupture is conservative drainage.
  • Placement of a large-bore (16–20 Fr) transurethral Foley catheter provides continuous decompression. An initial cystogram is commonly obtained at about 10 days; catheter duration, often 10–14 days or longer, depends on healing.
  • Confirmatory cystogram before catheter removal validates watertight healing.
  • Exceptions Requiring Surgical Repair: Penetrating bone spicules puncturing the bladder wall; concomitant open pelvic fracture; rectal or vaginal laceration; bladder neck involvement or wall entrapment. Repair is often performed during exploration or pelvic fixation, although evidence for preventing hardware infection is conflicting.
• Intraperitoneal Rupture Management:
  • Blunt intraperitoneal rupture requires prompt surgical exploration and repair (open or laparoscopic). Selected uncomplicated endoscopic perforations without peritonitis/ileus are a separate setting where conservative care may be appropriate.
  • Intraperitoneal urinary leakage risks peritonitis, intra-abdominal sepsis and systemic absorption of urea/creatinine that can mimic renal failure ("pseudo-renal failure"). These risks justify surgical repair after blunt rupture.
  • Surgical technique: Thorough abdominal exploration, debridement of non-viable edges, and a watertight absorbable-suture closure in one or two layers, supported by catheter drainage. After a simple repair in a healthy patient, removal at about 5–10 days may be appropriate; complex injuries or impaired healing need individualized duration and cystographic confirmation.

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Urethral Trauma

Urethral injuries are classified anatomically into anterior and posterior disruptions, differing completely in mechanism, anatomy, and surgical management.

Anatomical Classification and Mechanisms

1. Anterior Urethral Injuries:
   • Involves the bulbar, penile (pendulous), or fossa navicularis segments distal to the perineal membrane.
   • Mechanism: Typically a straddle injury (fall astride a bicycle crossbar, fence, or manhole) or direct kick to the perineum, crushing the bulbar urethra against the inferior surface of the pubic symphysis.
   • Extravasation Barriers:
     • In a penile urethral injury confined by intact Buck's fascia, urine and hematoma remain around the penile shaft ("sleeve" appearance).
     • With Buck's fascia disrupted, or a bulbar injury opening into the superficial perineal compartment, extravasation spreads into the superficial perineal pouch deep to Colles' fascia, extending into the scrotum, around the penis, and up the anterior abdominal wall beneath Scarpa's fascia, but stopped at the thighs by the fascia lata attachment.
2. Posterior Urethral Injuries:
   • Involves the membranous or prostatic urethra proximal to the perineal membrane.
   • Mechanism: High-energy blunt trauma causing pelvic fractures (motor vehicle accidents, crush injuries). Pelvic Fracture Urethral Distraction Defects (PFUDD) occur when shearing forces tear the membranous urethra at the puboprostatic ligaments and urogenital diaphragm.

Clinical Presentation: The Classic Triad

The diagnostic triad of urethral rupture consists of:

1. Blood at the external urethral meatus (present in 50%–75% of cases; the single most critical warning sign).
2. Inability to void / acute urinary retention.
3. A palpable, distended urinary bladder.

A butterfly perineal haematoma may be present. A high-riding or impalpable prostate is an unreliable sign; perform rectal examination primarily to detect associated rectal injury, rather than using prostate position to exclude or confirm urethral disruption.

Diagnostic Gold Standard: Retrograde Urethrography (RUG)

RUG is the standard early test in a stable male; flexible cystourethroscopy is an alternative. Postpone urethrography in an unstable patient until resuscitated:

• Use a 30-degree oblique projection. With an unstable pelvic fracture, adjust the X-ray beam rather than rotating the patient.
• A small-bore catheter (12 Fr) or dedicated cannula is placed in the fossa navicularis, the balloon inflated with 1–2 mL of saline, and 20–30 mL of water-soluble contrast gently injected under real-time fluoroscopic capture.
• Interpretation:
  • Extravasation with bladder filling suggests a partial tear.
  • Marked extravasation without bladder filling suggests complete disruption; RUG cannot always reliably distinguish partial from complete injury.

Management of Posterior Urethral Disruption (PFUDD)

• Emergency Initial Management:
  • After life-threatening injuries are addressed, establish early urinary drainage by a suitable transurethral or suprapubic catheter (SPC). Use ultrasound or direct vision for suprapubic placement.
  • In a partial tear, careful catheterization over a guidewire under direct vision (or single gentle catheterization attempt by an experienced urologist) may be considered, stopping if there is difficulty. Choose drainage according to expertise and bladder/pelvic anatomy.
• Primary Endoscopic Realignment (PER):
  • In a hemodynamically stable patient without severe associated injuries, PER can be performed within 48 to 72 hours.
  • Flexible or rigid cystoscopes are advanced simultaneously from above (via the suprapubic tract) and below (via the meatus) to "meet in the light" at the distraction gap, guiding a stenting catheter across the defect.
  • PER may reduce displacement, but does not reliably prevent stricture. Evidence that it shortens a later stricture or simplifies urethroplasty is conflicting. Avoid repeated endoscopic procedures after failed realignment; definitive urethroplasty may be required.
• Delayed Anastomotic Urethroplasty (Gold Standard):
  • If PER is not performed or fails, the patient is maintained on suprapubic drainage for 3 to 6 months.
  • Allows complete resorption of the pelvic hematoma and descent of the prostate back into its anatomical bed.
  • Formal delayed perineal anastomotic urethroplasty (with bulbomembranous excision and spatulated primary anastomosis) achieves cure rates exceeding 90%–95%.

Genitourinary Trauma Staging, Diagnostic Signatures & Management Protocols

Renal grades below use the 2018 scale reproduced in EAU 2026.

Penile Fracture and Testicular Trauma

Penile fracture is rupture of the tunica albuginea of an erect corpus cavernosum. A snap, immediate detumescence, pain and swelling after bending are characteristic. Obtain urgent urological assessment and surgical repair. Ultrasound/MRI can clarify an uncertain diagnosis but should not delay a clear urgent case. Assess associated urethral injury, especially with blood at the meatus or visible haematuria; RUG or intraoperative urethroscopy can be used as appropriate. A superficial haematoma with intact tunica is a different injury. Deep penetrating penile injuries need exploration and repair with preservation of viable tissue; small superficial wounds with intact Buck’s fascia may be managed conservatively.

After blunt scrotal trauma, ultrasound with Doppler assesses the testis, tunical contour and perfusion. Suspected rupture, or inconclusive imaging that cannot exclude it, warrants exploration. Evacuate clot, remove nonviable tissue and repair the tunica while preserving viable testis; orchiectomy is reserved for a nonsalvageable testis. A large haematocele can require surgery even without proven rupture; a small one may be observed when rupture is excluded. Penetrating scrotal injuries usually require exploration and assessment of both testes.

Worked decisions: A typical penile fracture needs repair, not several days of observation awaiting disappearance of swelling. A painful swollen testis with equivocal ultrasound and continuing suspicion of rupture needs exploration, not reassurance based solely on uncertain imaging. Counsel about erectile, fertility and atrophy risks and arrange follow-up.

Primary references: EAU Urological Trauma, genital trauma and AUA Urotrauma Guideline, 2020.