What is the treatment approach for splenic injuries based on the American Association for the Surgery of Trauma (AAST) grading system?

Treatment Approach for Splenic Injuries Based on AAST Grading

Hemodynamically stable patients with any grade of splenic injury should receive non-operative management (NOM) as the standard of care, with angiography/angioembolization (AG/AE) reserved for AAST Grade IV-V injuries or any grade with contrast blush on CT scan. 1

Initial Management Algorithm

Hemodynamic Status Assessment (Primary Determinant)

Hemodynamically unstable patients require immediate operative management regardless of AAST grade. 2

• Unstable patients unresponsive to resuscitation with any grade splenic injury need splenectomy 2
• Hemodynamic stability is more critical than anatomic injury grade in determining treatment strategy 3

Hemodynamically stable patients proceed to CT-based grading and selective intervention. 1, 3

Grade-Specific Treatment Protocols

AAST Grade I-II (Low-Grade Injuries)

• Observation with serial abdominal examinations and hematocrit checks every 6 hours for the first 24-72 hours 1
• NOM success rate exceeds 95% in these patients 1
• AG/AE is not routinely indicated even if contrast blush is present, as only 4% show active bleeding vascular injuries 1
• No routine post-discharge CT imaging required 1
• Activity restriction for 2 weeks with return to full activity at 6 weeks 1

AAST Grade III (Moderate Injuries)

• NOM with close observation is appropriate for patients without contrast blush 1
• Prophylactic AG/AE should NOT be performed routinely in Grade III injuries without vascular abnormalities 1
• NOM failure occurs in only 3% of Grade III lesions without blush 1
• The AG/AE-related morbidity of 47% versus 10% for NOM alone does not justify routine embolization 1
• Consider repeat CT at 36-72 hours if hematocrit is decreasing 1
• Activity restriction for 2.5-3 months before return to normal activity 1

AAST Grade IV-V (High-Grade Injuries)

These patients require AG/AE if hemodynamically stable, as NOM failure without embolization is unacceptably high. 1

• NOM failure rates: 43.7% for Grade IV and 83.1% for Grade V without AG/AE versus 17.3% and 25.0% respectively with AG/AE 1
• Success rate of AG/AE ranges from 73-100% 1
• Coils should be preferred over temporary agents for embolization 1
• Proximal or combined proximal/distal embolization should be used for severe lesions 1
• Level I trauma centers with AG/AE rates >10% have significantly higher spleen salvage rates 1
• Activity restriction for 4-6 months 1

CT Findings That Mandate Intervention

Contrast Blush/Active Bleeding

Any patient with contrast blush on CT requires AG/AE regardless of AAST grade. 1

• NOM failure with contrast blush treated without AG/AE ranges from 67-82% 1
• Intraperitoneal splenic blush has significantly higher risk of hemodynamic deterioration than intraparenchymal bleeding (p < 0.001) 1
• Angiographic procedure without embolization increases twofold the risk of re-bleeding and NOM failure 1

Pseudoaneurysm (PSA) or Arteriovenous Fistula

• These vascular injuries require AG/AE as they show higher NOM failure rates 1
• PSA accuracy for predicting need for AG/AE is 83% 1

Operative Management Indications

Proceed directly to splenectomy for: 2

• Hemodynamic instability despite resuscitation
• Failed NOM with ongoing bleeding or deterioration
• Total splenic avulsion (Grade V with complete devascularization)
• Grade IV injuries in centers without AG/AE capability
• Unipolar apical laceration with uncontrolled active bleeding

Critical Pitfalls and Caveats

Timing of AG/AE

• Earlier AG/AE correlates with fewer splenectomies - delay increases failure risk 1
• Multi-institutional data shows AG/AE is an independent predictor of spleen salvage and mortality reduction 1

False-Negative Angiography

• 2.3-47% of CT-detected contrast blush cannot be confirmed at subsequent angiography 1
• However, this should not deter proceeding to angiography, as the presence of blush remains highly predictive

Grade III Controversy

• Do not routinely embolize Grade III injuries without vascular abnormalities 1
• Widening AG/AE criteria from Grade IV-V to Grade III-V only marginally decreases NOM failure but significantly increases morbidity 1
• No outcome deterioration in mortality or complications when Grade III is excluded from routine AG/AE protocols 1

Pediatric Considerations

• NOM is even more successful in children (95-100% success rate) regardless of AAST grade 1
• Children have thicker splenic capsules and more efficient vascular contraction 1
• "Less is more" approach recommended for imaging to reduce radiation exposure 1