How are splenic injuries graded and what is the recommended management for each grade based on hemodynamic stability?

Splenic Injury Classification and Management

Classification Systems

Splenic injuries are classified using both the anatomic AAST-OIS grading system (I-V) and the WSES classification that integrates hemodynamic status, creating a more clinically relevant framework for treatment decisions. 1

AAST-OIS Anatomic Grading

• Grade I: Subcapsular hematoma <10% surface area OR capsular laceration <1 cm depth 1
• Grade II: Subcapsular hematoma 10-50% surface area OR intraparenchymal hematoma <5 cm OR laceration 1-3 cm depth not involving trabecular vessels 1
• Grade III: Subcapsular hematoma >50% surface area or expanding OR ruptured hematoma OR intraparenchymal hematoma >5 cm OR laceration >3 cm depth or involving trabecular vessels 1
• Grade IV: Laceration involving segmental or hilar vessels with major devascularization (>25% of spleen) 1
• Grade V: Completely shattered spleen OR hilar vascular injury devascularizing the spleen 1

WSES Clinical Classification (Integrating Hemodynamics)

The WSES classification supersedes pure anatomic grading by incorporating hemodynamic stability, which is the critical determinant of management strategy. 1

• WSES Class I (Minor): Hemodynamically stable AAST-OIS Grade I-II injuries 1
• WSES Class II (Moderate): Hemodynamically stable AAST-OIS Grade III injuries 1
• WSES Class III (Moderate): Hemodynamically stable AAST-OIS Grade IV-V injuries 1
• WSES Class IV (Severe): Hemodynamically unstable AAST-OIS Grade I-V injuries (any grade with instability) 1

Diagnostic Approach

Contrast-enhanced CT scan is the gold standard for evaluating splenic injuries in hemodynamically stable patients, with sensitivity and specificity approaching 96-100%. 1, 2, 3

Imaging Selection Algorithm

• E-FAST ultrasound: Rapid initial assessment for free fluid in unstable patients; sensitivity 66% in adults, role unclear in pediatrics 1
• Contrast-enhanced CT: Mandatory for all hemodynamically stable patients to grade injury, detect active bleeding (contrast blush), pseudoaneurysms, and associated injuries 1, 3
• Doppler ultrasound/CEUS: Useful adjuncts for evaluating splenic vascularization and serial follow-up monitoring 1, 2

Critical Imaging Findings

CT findings including injury grade, amount of hemoperitoneum, contrast blush, and pseudoaneurysm presence do NOT reliably predict nonoperative management failure, though they guide treatment intensity. 1 However, CT commonly underestimates injury severity compared to operative findings (53% underestimation rate in one series). 4

Management Strategy by WSES Class

WSES Class IV (Hemodynamically Unstable - Any Grade)

Immediate operative management is mandatory for any patient with hemodynamic instability (systolic BP <90 mmHg, shock index >1, or requiring ≥4-6 units PRBC in 24 hours), regardless of anatomic injury grade. 1, 5

• Hemodynamic instability is defined as: persistent hypotension despite adequate fluid resuscitation, transient response to fluids with recurrent signs of shock, or inability to stabilize sufficiently for interventional radiology 1
• Peritonitis on examination mandates immediate laparotomy 3, 6
• Splenectomy is performed in 76.9% of operative cases, though splenorrhaphy should be attempted when feasible 7, 6

WSES Class I-III (Hemodynamically Stable)

Nonoperative management (NOM) is the first-line treatment for all hemodynamically stable patients regardless of injury grade (I-V), with success rates of 80-95%. 1, 3, 6

Prerequisites for NOM

NOM should only be attempted in facilities with: 1

• Continuous hemodynamic monitoring capability (ICU/high-dependency unit)
• Serial clinical examination and laboratory assessment
• Immediate access to interventional radiology (within 60 minutes)
• Immediately available operating room and blood products
• Alternatively, rapid transfer protocols to trauma centers meeting these criteria

Monitoring Protocol During NOM

• Admission to monitored setting for 1-3 days 5
• Serial hemoglobin checks: Every 4-6 hours for first 24 hours, then once or twice daily thereafter 5
• Clinical examination: Serial abdominal exams to detect peritonitis or hemodynamic deterioration 3

Role of Splenic Artery Embolization (SAE)

Angioembolization should be performed within 60 minutes for hemodynamically stable patients with contrast extravasation (blush), pseudoaneurysm, or arteriovenous fistula on CT, regardless of injury grade. 5, 8, 6

• SAE is particularly indicated for stable patients with Grade IV-V injuries showing active extravasation 8, 6
• Both proximal and distal embolization techniques are effective with no superiority demonstrated 6
• SAE can be considered even in patients with transient hypotension who respond to resuscitation 9
• Morbidity is significantly lower with SAE (OR 0.61) compared to immediate splenectomy when appropriately selected 9

Indications for Operative Management in Stable Patients

Beyond hemodynamic instability, surgery is indicated for: 5

• Associated intra-abdominal injuries requiring laparotomy
• Transfusion requirement of ≥5 units PRBC (82% expert consensus) 5
• Peritoneal signs on examination 3, 6

NOM Failure and Salvage Surgery

Failure of NOM (occurring in 5-20% of cases) results in significantly higher morbidity (OR 5.39 for SAE failure, OR 1.95 for observation failure) and longer hospital stays without increased mortality. 9

• Failure rates are higher in adults (33%) compared to children (16%) even with lower injury grades 4
• Failed NOM patients require more blood transfusions and have prolonged hospitalizations 7, 9
• Close monitoring is essential to detect failure early and minimize complications

Pediatric-Specific Considerations

NOM is the first-line treatment for hemodynamically stable pediatric patients with blunt splenic trauma, with even higher success rates than adults. 1

Pediatric Hemodynamic Stability Definition

• Systolic BP ≥ (90 mmHg + 2 × age in years); lower limit is <(70 mmHg + 2 × age in years) 1
• Positive response to fluid resuscitation: 3 boluses of 20 mL/kg crystalloid before blood products 1
• Clinical indicators: heart rate reduction, improved mental status, return of peripheral pulses, normal skin color, increased BP and urine output 1

Pediatric Imaging

• E-FAST has unclear utility; positive FAST should be followed by urgent CT in stable patients 1
• Low-dose CT protocols preferred (3-6 mSv vs 11-24 mSv) to minimize radiation exposure 1
• Complete abdominal ultrasound may avoid CT in low-risk stable patients 1

Pediatric NOM Success

• Children with Grade I-III injuries have high NOM success rates (84%) 4
• NOM should be attempted even with concomitant head trauma unless instability is attributable to intra-abdominal bleeding 1
• Transfer to dedicated pediatric trauma centers recommended for moderate-severe injuries after stabilization 1

Follow-Up and Post-Discharge Management

Routine post-discharge imaging is NOT indicated (88% expert consensus); imaging should be guided by clinical symptoms only. 5

• Repeat CT during admission should be based on clinical deterioration, not routine protocols 3
• Activity restrictions and return-to-play guidelines should follow institutional protocols
• Vaccination status and thromboprophylaxis considerations apply primarily to splenectomy patients

Common Pitfalls

• Do not rely solely on CT grade to predict NOM failure—hemodynamic status and transfusion requirements are more predictive 1
• Do not delay SAE beyond 60 minutes in stable patients with contrast blush 5
• Do not attempt NOM in facilities lacking immediate surgical backup and interventional radiology 1
• Do not perform routine follow-up imaging in asymptomatic patients post-discharge 5
• Recognize that CT underestimates injury severity in >50% of cases—clinical judgment supersedes imaging 4