What is the management plan for a patient with an American Association for the Surgery of Trauma (AAST) renal grade injury?

Management of AAST Renal Grade Injuries

Hemodynamic stability determines the management approach for all AAST renal grade injuries, with non-operative management being the standard of care for stable patients across all injury grades (I-V), while hemodynamically unstable patients require immediate intervention. 1

Initial Diagnostic Approach

Perform IV contrast-enhanced CT with immediate and delayed phases (10-15 minutes post-contrast) in all stable trauma patients with concerning mechanisms (rapid deceleration, significant flank blow, rib fracture, flank ecchymosis) or penetrating injury to abdomen/flank/lower chest, regardless of hematuria presence. 1, 2 Up to 34% of multisystem trauma patients have renal injury despite absent hematuria or hemodynamic instability. 1

The delayed phase imaging is mandatory to identify collecting system injuries and contrast extravasation, which may be missed on initial imaging in up to 1% of high-grade injuries. 2, 3

Management Algorithm Based on Hemodynamic Status

Hemodynamically Stable Patients (All AAST Grades I-V)

Non-operative management (NOM) is the standard of care for all hemodynamically stable patients regardless of injury grade, with 93% success rate. 1, 2 This approach includes:

• Close hemodynamic monitoring with serial hematocrit values 1
• ICU admission for high-grade injuries 1
• Bed rest until gross hematuria resolves 2
• Blood transfusion as needed 1

Isolated urinary extravasation is not an absolute contraindication to NOM in absence of other laparotomy indications. 1 Devitalized parenchyma alone does not mandate surgery in the acute setting. 1

Hemodynamically Unstable Patients (Non-responders)

Immediate intervention is mandatory for patients with persistent hypotension (SBP <90 mmHg) despite active resuscitation. 1 Options include:

• Immediate surgical exploration for uncontrolled bleeding, renal pedicle avulsion with expanding hematoma, or main renal vein injury without self-limiting bleeding 1, 4
• REBOA (Resuscitative Endovascular Balloon Occlusion of the Aorta) as a bridge to definitive hemorrhage control 1, 4

Perform one-shot IVP (2 mL/kg IV contrast with single image at 10-15 minutes) prior to renal exploration to document contralateral kidney function if CT was not obtained. 1

Hemodynamically Transient Responders

In highly selected settings with immediate OR availability, experienced surgeons, adequate resuscitation capacity, and immediate blood product access, consider angioembolization over immediate surgery. 1 This requires no other indications for laparotomy. 1

In children with labile hemodynamics, angiography with super-selective angioembolization should be first choice if angiographic suite, surgery, and blood products are immediately available. 1

Role of Angioembolization

Indications for Angiography/Angioembolization in Stable Patients

Perform angiography with potential super-selective angioembolization for: 1

• Arterial contrast extravasation on CT
• Pseudoaneurysms
• Arteriovenous fistulas
• Non-self-limiting gross hematuria
• Progressive hemoglobin decrease during NOM

Angioembolization achieves 63-100% success rates and should be performed as selectively as possible. 1, 2 Blind angioembolization is not indicated when angiography is negative for active bleeding, regardless of CT findings. 1

Special Considerations

For solitary kidney with moderate (AAST III) or severe (AAST IV-V) injury and arterial contrast extravasation, angiography with super-selective angioembolization should be first choice. 1

For main renal artery injury/dissection/occlusion in specialized centers, consider angioembolization or percutaneous revascularization with stent/stentgraft if warm ischemia time <240 minutes. 1, 4 However, arterial repair success rates are only 25-35%. 4

Repeat angioembolization is justified if initial attempt fails, with similar success rates to initial intervention. 1

Management of Collecting System Injuries

Grade IV collecting system injuries require close monitoring with repeat CT at 48-72 hours, as urinary leak may be initially missed. 2, 3 Intervention is reserved for symptomatic or enlarging urinomas. 2

Drainage options include: 3, 4

• Ureteral stent placement
• Percutaneous urinoma drain
• Percutaneous nephrostomy

Follow-up and Monitoring

Early Follow-up (Grade IV-V Injuries)

Perform contrast-enhanced CT with excretory phase within 48 hours for all grade V injuries and high-grade injuries with concerning features. 3 This early imaging is crucial as grade V injuries have high complication rates. 3

Indications for Additional Imaging

Obtain further imaging for: 3

• Fever
• Worsening flank pain
• Ongoing blood loss
• Abdominal distention
• Recurrent or worsening hematuria

Surveillance for Complications

Monitor for secondary hemorrhage, which occurs in up to 25% of moderate/severe injuries within 2 weeks, with hematuria being the most common presenting sign. 2, 3 Prompt contrast-enhanced CT is indicated if hematuria develops. 3

Monitor blood pressure for up to one year to detect renovascular hypertension, which occurs in 0-6.6% of cases. 2, 3, 4

Return to Activity

Avoid sports activities until microscopic hematuria resolves. 2 Timing varies by injury severity:

• Lower grade injuries: Earlier return possible
• Severe (Grade IV-V) injuries: May require 6-12 months before return to sports 3

Common Pitfalls to Avoid

• Do not rush to surgery for devascularized kidney in stable patients without other laparotomy indications 1, 4
• Do not rely solely on hematuria presence to determine imaging need, as 10-25% of high-grade injuries present without hematuria 2
• Do not attempt arterial repair with prolonged warm ischemia time (>240 minutes) 4
• Do not fail to perform 48-hour follow-up CT for grade V injuries, which have high complication rates 3
• Do not perform angioembolization for main renal vein injury—these require surgical intervention 1