Revision of Current American Association for the Surgery of Trauma Renal Injury Grading System

Background: We propose a revision of the original 1989 renal organ injury system established by the American Association for the Surgery of Trauma based on our institution's >25-year longitudinal experience. Our goal is to expand the current grading system to include segmental vascular injuries and ureteral pelvic injuries and to establish a more rigorous definition of severe grade IV and V renal injuries. Methods: We retrospectively reviewed our prospectively gathered contiguous renal database of 3,580 renal injuries to describe a revised renal grading injury scale based on clinical renal salvage outcomes. We focused on the mechanism of injury, the stability of the patient, radiographic imaging, associated nonrenal injuries, and clinical salvage outcome data. Results: No changes were made in the definition of grade I to III injuries. The revised grade IV classification includes all collecting system, renal pelvis injuries and segmental arterial and/or venous injuries. The revised grade V classification is limited to main renal artery and/or vein injuries, including laceration, avulsion, and thrombosis. We compared the nephrectomy rate and clinical renal salvage rate between the original 1989 renal organ injury system with our revised renal injury staging classification. Conclusion: The revised renal injury staging classification provides complete and clear definitions of renal trauma while still performing its fundamental objective to reflect increasingly complex renal injuries. Uniform language and classification of renal injuries will enhance discussion, clinical investigation, and research of renal trauma.