What is the grading system for spleen laceration?

Spleen Laceration Grading System

The standard grading system for splenic laceration is the American Association for the Surgery of Trauma (AAST) Organ Injury Scale, which classifies injuries from Grade I to V based on the extent of parenchymal disruption, subcapsular hematoma, and vascular involvement. 1

AAST Grading System for Splenic Injuries

Grade I

• Subcapsular hematoma < 10% of surface area 1
• Capsular tear < 1 cm parenchymal depth 1

Grade II

• Subcapsular hematoma 10-50% of surface area 1
• Intraparenchymal hematoma < 5 cm diameter 1
• Laceration 1-3 cm parenchymal depth not involving trabecular vessels 1

Grade III

• Subcapsular hematoma > 50% of surface area or expanding 1
• Ruptured subcapsular or parenchymal hematoma 1
• Intraparenchymal hematoma > 5 cm 1
• Laceration > 3 cm parenchymal depth or involving trabecular vessels 1

Grade IV

• Laceration of segmental or hilar vessels producing major devascularization (> 25% of spleen) 1

Grade V

• Completely shattered spleen 1
• Hilar vascular injury which devascularizes spleen 1

World Society of Emergency Surgery (WSES) Classification

The WSES has developed a complementary classification system that incorporates both the AAST anatomic grading and hemodynamic status to guide management decisions: 1

WSES Class I (Minor)

• Hemodynamically stable patients with AAST Grade I-II injuries 1

WSES Class II (Moderate)

• Hemodynamically stable patients with AAST Grade III injuries 1

WSES Class III (Moderate)

• Hemodynamically stable patients with AAST Grade IV-V injuries 1

WSES Class IV (Severe)

• Hemodynamically unstable patients with AAST Grade I-V injuries 1

Clinical Implications of Grading

• The AAST grading system helps predict the need for intervention and guides treatment decisions 2
• Hemodynamic status is more important than anatomic grade in determining management approach 3
• Non-operative management (NOM) is the standard of care for hemodynamically stable patients regardless of injury grade 2, 3
• Angiography/angioembolization should be considered for WSES class III injuries (hemodynamically stable with high-grade AAST injuries) 2

Pitfalls in Grading Splenic Injuries

• Recent research shows only moderate inter-rater reliability (kappa = 0.38) when radiologists grade splenic injuries using the AAST system 4
• Agreement improves when simplifying to low-grade (I-III) versus high-grade (IV-V) injuries (kappa = 0.77) 4
• Common sources of disagreement include differentiating between clefts versus lacerations, perisplenic fluid versus subcapsular hematoma, and identification of subtle vascular injuries 4
• The 2018 revision of the AAST OIS now incorporates vascular injuries (active bleeding, pseudoaneurysm, arteriovenous fistulae) which automatically elevate the grade to at least IV 5

Modern Approaches to Grading

• The Baltimore CT grading system was developed in 2007 as an alternative that better predicts the need for angiography/embolization 6
• Recent research is exploring automated deep learning approaches to standardize AAST grading with substantial agreement (weighted κ = 0.79) between automated and consensus expert grading 7
• Both anatomic injury grade and hemodynamic status should be considered when determining management strategy 1, 3