What is the recommended treatment for a renal laceration based on the patient’s hemodynamic stability and injury grade?

Treatment for Renal Laceration

Hemodynamically stable patients with renal lacerations of any grade should be managed non-operatively with close monitoring, while hemodynamically unstable patients require immediate intervention with either surgical exploration or angioembolization depending on resource availability. 1

Initial Management Based on Hemodynamic Status

Hemodynamically Stable Patients (SBP ≥90 mmHg)

• Non-operative management (NOM) is the standard of care for all hemodynamically stable patients regardless of AAST injury grade (I-V), with a 93% success rate. 2, 1
• NOM consists of close hemodynamic monitoring, bed rest, ICU admission when appropriate, serial hematocrit measurements, and blood transfusion as needed. 1
• This approach avoids unnecessary surgery, decreases unnecessary nephrectomy rates, and preserves renal function. 1

Hemodynamically Unstable Patients (SBP <90 mmHg despite resuscitation)

• Immediate intervention is mandatory for patients with persistent hypotension despite active resuscitation. 1
• Hemodynamically unstable patients should undergo immediate surgical exploration rather than angiography, as angiography is time-intensive and remote from the operating room. 1
• Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) may be used as a bridge to definitive hemorrhage control procedures. 1, 2
• The goal of operative exploration is to control bleeding first, repair the kidney when possible, and establish perirenal drainage. 1

Role of Angioembolization

Indications for Angioembolization in Stable Patients

• Angiography with super-selective angioembolization should be performed for arterial contrast extravasation on CT scan, pseudoaneurysms, arteriovenous fistulas, or progressive hemoglobin decrease during NOM. 1, 2
• In hemodynamically stable patients with solitary kidney and moderate (AAST III) or severe (AAST IV-V) renal trauma with arterial contrast extravasation, angioembolization should be considered as first choice. 1
• Super-selective angioembolization should be used when possible to preserve renal function, with success rates of 63-100%. 2

Contraindications and Limitations

• In severe injury with main renal vein injury without self-limiting bleeding, angioembolization is not indicated and patients should undergo surgical intervention. 1
• Angioembolization may be considered in selected hemodynamically transient responder patients only with immediate availability of operating room, surgeon, adequate resuscitation, and immediate access to blood products. 1
• Predictors of angioembolization failure include gross hematuria, hemodynamic instability, grade V trauma, and urinary extravasation, though success rates remain relatively high (60-65%) even in these subgroups. 3

Management of Collecting System Injuries and Urinary Extravasation

Initial Observation Strategy

• Patients with renal parenchymal injury and urinary extravasation may be initially observed without intervention, as parenchymal collecting system injuries often resolve spontaneously. 1
• This observation period is appropriate in stable patients where renal pelvis or proximal ureteral injury is not suspected. 1

Indications for Intervention

• Urinary drainage should be performed in the presence of complications such as enlarging urinoma, fever, increasing pain, ileus, fistula, or infection. 1
• Drainage options include ureteral stent placement (minimally invasive first-line), which may be augmented by percutaneous urinoma drain, percutaneous nephrostomy, or both. 1, 2
• When renal pelvis or proximal ureteral avulsion is suspected (large medial urinoma or contrast extravasation on delayed images without distal ureteral contrast), prompt intervention is warranted. 1

Follow-up Imaging Protocol

High-Grade Injuries (AAST Grade IV-V)

• Follow-up CT imaging after 48 hours is mandatory for patients with deep renal lacerations (AAST Grade IV-V) because these injuries are prone to developing complications such as urinoma or hemorrhage. 1, 4
• Contrast-enhanced CT with excretory phase should be performed within 48 hours for all grade V injuries, as urinary leak may be missed on initial imaging in up to 1% of high-grade injuries. 4

Low-Grade Injuries (AAST Grade I-III)

• Routine follow-up CT imaging is not advised for uncomplicated AAST Grade I-III injuries because it is unlikely to change clinical management. 1
• These low-grade injuries have a low risk of complications and rarely require intervention. 1

Symptom-Based Imaging

• Follow-up imaging should be performed when complications are suspected, including fever, worsening flank pain, ongoing blood loss, abdominal distention, or recurrent/worsening hematuria. 1, 4
• Periodic blood pressure monitoring up to one year after injury may uncover rare instances of post-injury renovascular hypertension. 1

Surgical Management Considerations

Indications for Operative Management

• Hemodynamically unstable and non-responder patients (WSES Class IV) should undergo operative management. 1
• Severe renal vascular injuries without self-limiting bleeding require operative management. 1
• In hemodynamically unstable patients with expanding zone II hematomas, kidney-preserving techniques are conditionally recommended over nephrectomy when feasible. 5

What NOT to Operate On

• The presence of non-viable tissue (devascularized kidney) is not an indication for operative management in the acute setting in the absence of other indications for laparotomy. 1
• Devitalized parenchyma alone, while suggested as a risk factor for septic complications, has inconclusive evidence supporting intervention based solely on this radiographic finding. 1

Common Pitfalls to Avoid

• Do not rush to surgery for devascularized kidney in stable patients without other laparotomy indications, as this leads to unnecessary surgical intervention and potential nephrectomy. 2, 1
• Do not rely solely on hematuria presence to determine imaging need, as 10-25% of high-grade injuries present without hematuria and 36-40% of renal injuries may have absent hematuria. 2, 1
• Do not fail to perform 48-hour follow-up CT for grade IV-V injuries, which have high complication rates requiring potential intervention. 4, 1
• Do not attempt arterial repair with prolonged warm ischemia time (>240 minutes), as this leads to poor outcomes. 2, 1
• Do not perform angioembolization for main renal vein injury, as these require surgical intervention. 2, 1

Pediatric Considerations

• In children, angiography and super-selective angioembolization should be the first choice even with active bleeding and labile hemodynamics, if there is immediate availability of angiographic suite, immediate access to surgery, blood products, and intensive care environment. 1
• Hemodynamic stability in pediatric patients is defined as SBP of 90 mmHg plus twice the child's age in years. 6