AAST Pancreas Organ Injury Scale

{
  "categories": [
    {
      "outcome_code": "I",
      "grade_criteria": "pancreatic_edema_or_contusion_without_laceration_or_hematoma",
      "subgrades": [
        "I-A_traumatic_edema",
        "I-B_contusion_without_hematoma_or_laceration"
      ]
    },
    {
      "outcome_code": "II",
      "grade_criteria": "intact_main_duct_or_laceration_or_hematoma_less_than_50_percent_depth_without_definitive_duct_evaluation_or_50_percent_or_greater_with_confirmed_intact_duct",
      "subgrades": [
        "II-A_neck_body_or_tail",
        "II-B_head_or_uncinate"
      ]
    },
    {
      "outcome_code": "III",
      "grade_criteria": "main_duct_injury_or_laceration_or_hematoma_50_percent_or_greater_depth_in_neck_body_or_tail",
      "subgrades": [
        "III-N_no_definitive_duct_evaluation",
        "III-A_confirmed_duct_injury_with_alignment",
        "III-B_complete_transection_or_distraction"
      ]
    },
    {
      "outcome_code": "IV",
      "grade_criteria": "main_duct_injury_or_laceration_or_hematoma_50_percent_or_greater_depth_in_head_or_uncinate",
      "subgrades": [
        "IV-N_no_definitive_duct_evaluation",
        "IV-A_confirmed_duct_injury_with_alignment",
        "IV-B_complete_transection_or_distraction"
      ]
    },
    {
      "outcome_code": "V",
      "grade_criteria": "destructive_blast_or_crush_injury_with_nonviable_pancreatic_head",
      "subgrades": [
        "V-N_no_definitive_pancreatobiliary_duct_evaluation",
        "V-A_intact_main_duct_in_head",
        "V-B_main_pancreatic_duct_injury",
        "V-C_intrapancreatic_common_bile_duct_injury",
        "V-D_ductal_avulsion_from_duodenum_or_sphincter_disruption"
      ]
    }
  ],
  "applicability": {
    "intended_use": "Standardized anatomic grading of traumatic pancreatic injury using radiographic, operative or pathologic findings under the 2024 AAST revision.",
    "classification_unit": "one_pancreatic_injury_episode_with_main_grade_and_required_subgrade",
    "required_inputs": [
      "injury_type_edema_contusion_hematoma_laceration_or_destruction",
      "maximum_parenchymal_depth_percentage",
      "location_relative_to_portal_vein_and_SMV",
      "main_pancreatic_duct_evaluation_method_and_result",
      "head_viability",
      "common_bile_duct_ampullary_and_duodenal_relationship_when_grade_V_is_possible"
    ],
    "outside_scope": [
      "acute_pancreatitis_severity",
      "Balthazar_or_modified_CTSI",
      "management_selection_from_grade_alone",
      "individual_complication_or_mortality_probability",
      "silent_use_of_the_1990_grade_map"
    ]
  },
  "revision_guard": {
    "current_release": "Use the AAST 2024 revision published in 2025, not the 1990 OIS, whenever the current framework is requested.",
    "key_changes": [
      "head_contusion_without_laceration_is_grade_I",
      "all_lacerations_with_intact_duct_can_be_grade_II_regardless_of_head_location",
      "deep_or_ductal_injuries_use_explicit_location_and_N_A_B_subgrades",
      "destructive_nonviable_head_injury_uses_grade_V_pancreatobiliary_subgrades"
    ],
    "legacy_collision": "The old statement that any proximal injury is grade IV is obsolete. A head or uncinate laceration with an intact duct belongs in II-B under the current revision."
  },
  "assignment_algorithm": [
    "Confirm traumatic mechanism, study timing and whether the evidence source is CT, MRCP, ERCP, surgery, intraoperative ultrasound or pathology.",
    "Classify edema or contusion without laceration or hematoma as grade I and assign I-A or I-B.",
    "For laceration or hematoma, measure maximum depth in either anteroposterior or craniocaudal plane and determine whether the main duct was definitively evaluated.",
    "If the main duct is confirmed intact, assign grade II and choose II-A for neck/body/tail or II-B for head/uncinate even when depth is 50 percent or greater.",
    "If depth is less than 50 percent and no definitive duct evaluation exists, assign grade II by location; do not claim the duct is intact.",
    "If depth is 50 percent or greater without definitive duct evaluation, use grade III-N in neck/body/tail or IV-N in head/uncinate.",
    "If main-duct injury is confirmed, use grade III in neck/body/tail or IV in head/uncinate, then A for maintained alignment or B for complete transection or distraction.",
    "Use grade V only for destructive blast or crush injury with nonviable pancreatic head, then assign N, A, B, C or D from pancreatobiliary duct findings."
  ],
  "anatomy_and_measurement": {
    "depth": "Measure laceration or hematoma depth in the anteroposterior or craniocaudal plane, using whichever places the main duct at risk. Exactly 50 percent enters the deep-injury branch unless an intact duct is definitively shown.",
    "neck_body_tail": "The injury is in neck, body or tail when it overlies or lies to the left of the portal vein or superior mesenteric vein.",
    "head_uncinate": "Use head or uncinate when any part of the laceration is to the right of or posterior to the superior mesenteric vein.",
    "mixed_location": "When a deep injury crosses the landmark, preserve the full course and use the higher location-dependent grade supported by the current table rather than averaging locations.",
    "duct_alignment": "Subgrade A means confirmed main-duct injury with maintained alignment; subgrade B means complete transection and/or distracted ends."
  },
  "duct_evaluation_gate": {
    "CT_role": "Contrast-enhanced CT detects parenchymal and associated injury but has limited sensitivity and specificity for main-duct injury, especially early after trauma. A deep CT injury cannot be promoted from N to A or B without definitive duct evidence.",
    "MRCP_role": "MRCP is noninvasive and can demonstrate continuity or disruption, but technical quality and local expertise affect confidence; secretin use and timing should be stated when relevant.",
    "ERCP_role": "ERCP can directly define leak, partial disruption and complete transection and may enable therapy, but it is invasive and should be selected according to stability, expertise and whether the result changes care.",
    "operative_role": "Direct inspection alone may miss duct injury; operative cholangiopancreatography, intraoperative ultrasound or pathology can provide definitive evidence when performed.",
    "N_semantics": "N means no definitive duct interrogation for a deep injury. It is an uncertainty subgrade, not confirmation that the duct is normal and not a lower biologic severity state."
  },
  "decisive_boundaries": {
    "grade_I_to_II": "Edema or contusion without laceration or hematoma is I; any laceration or hematoma enters II or higher according to depth and duct status.",
    "shallow_uninvestigated_to_deep_uninvestigated": "Less than 50 percent depth without definitive duct evaluation is II; exactly 50 percent or greater becomes III-N or IV-N by location.",
    "intact_duct_exception": "A laceration or hematoma at least 50 percent deep can remain grade II only when the main duct is definitively intact.",
    "grade_III_to_IV": "Deep or ductal injury overlying or left of the PV/SMV is III; involvement to the right of or posterior to the SMV is IV.",
    "grade_IV_to_V": "Grade IV can be severe ductal injury in viable head tissue; V requires destructive blast or crush injury with nonviable pancreatic head.",
    "V_subgrades": "V-A preserves the main duct, V-B injures it, V-C injures the intrapancreatic common bile duct and V-D avulses ducts from the duodenum or disrupts the sphincter; report every supported component."
  },
  "management_boundary": {
    "release_timing": "The WSES-AAST 2019 guideline predates the 2024 grade revision and supplies management context, not a one-to-one current-subgrade treatment table.",
    "low_grade": "Stable grade I-II injury without another indication for laparotomy is often considered for nonoperative management and close follow-up, but duct confidence, age, associated injuries and center capability matter.",
    "ductal_injury": "Grades III-IV require early multidisciplinary trauma, hepatopancreatobiliary, interventional endoscopy and radiology assessment. Resection, drainage, reconstruction, endoscopic therapy or selected nonoperative care depends on location, partial versus complete duct injury, time from trauma and patient context.",
    "destructive_head": "Grade V triggers urgent specialist and damage-control planning. It does not automatically mandate pancreaticoduodenectomy; viability, duodenal and biliary injury, hemorrhage, physiology and staged reconstruction options determine the operation.",
    "instability": "Hemodynamic instability, peritonitis, uncontrolled bleeding or associated hollow-viscus and vascular injuries can require urgent operation independently of pancreatic grade.",
    "surveillance": "Track fistula, leak, pancreatitis, collections, pseudocyst, abscess, hemorrhage, duct stricture and distal atrophy or endocrine/exocrine dysfunction separately from the initial grade."
  },
  "risk_interpretation": {
    "population_gradient": "Higher grade and duct disruption are associated with more complex care and complications in cohorts, but the revised subgrades are not yet a portable patient-level probability model.",
    "major_modifiers": [
      "hemodynamic_status",
      "associated_duodenal_biliary_or_vascular_injury",
      "partial_versus_complete_duct_injury",
      "diagnostic_delay",
      "adult_or_pediatric_population",
      "center_expertise_and_resources"
    ],
    "prohibited_inferences": [
      "grade_II_proves_intact_duct_when_not_interrogated",
      "grade_III_requires_distal_pancreatectomy_in_every_patient",
      "grade_IV_or_V_requires_Whipple",
      "universal_pseudocyst_or_mortality_percentage",
      "individual_functional_outcome"
    ]
  },
  "system_boundaries": {
    "WSES": "WSES classes integrate hemodynamics and older AAST anatomy. State the edition and do not silently crosswalk a 2019 WSES class to a 2024 AAST subgrade.",
    "pancreatitis_frameworks": "Revised Atlanta, Balthazar CTSI and modified CTSI classify acute pancreatitis rather than traumatic pancreatic anatomy and duct integrity."
  },
  "agent_output_contract": [
    "Return trauma timing, physiology, evidence source and technical adequacy.",
    "Return injury type, depth percentage in the declared plane and exact location relative to PV/SMV.",
    "Return duct evaluation method and status: not definitively evaluated, intact, injured with alignment, complete transection or distraction.",
    "Return current main grade I-V plus the required subgrade and explicitly name the 2024 revision.",
    "Return associated duodenal, biliary, vascular and other abdominal injuries separately.",
    "Separate anatomic grade, uncertainty, management options, complication surveillance and prognosis."
  ],
  "missing_input_behavior": [
    "Without definitive duct evaluation, use the depth- and location-based N pathway rather than guessing duct integrity.",
    "If CT is initially negative but mechanism, enzymes, pain or secondary signs remain concerning, preserve suspicion and recommend clinically appropriate reassessment rather than declaring no injury.",
    "If depth is near 50 percent, return the measured range and adjacent possible grades; do not round across the boundary invisibly.",
    "If the injury crosses the PV/SMV landmark or head viability is unclear, withhold a single definitive grade and request expert source review or complementary evaluation according to urgency.",
    "Without hemodynamic and associated-injury context, return the anatomic grade but withhold an autonomous treatment pathway."
  ],
  "supporting_sources": [
    {
      "role": "current_scale",
      "citation": "Notrica et al. J Trauma Acute Care Surg. 2025;98:442-447",
      "doi": "10.1097/TA.0000000000004522",
      "pmid": "39898876"
    },
    {
      "role": "current_imaging_context",
      "citation": "Lanier and Mellnick. Can Assoc Radiol J. 2026",
      "doi": "10.1177/08465371261424865",
      "pmid": "41696877"
    },
    {
      "role": "management_context_predating_revision",
      "citation": "Coccolini et al. World J Emerg Surg. 2019;14:56",
      "doi": "10.1186/s13017-019-0278-6",
      "pmcid": "PMC6907251"
    }
  ],
  "source_locator": "Notrica et al. 2025, DOI 10.1097/TA.0000000000004522, 2024 revision and Table 1; AAST table reproduced with permission in Holcomb and Ashcraft's Pediatric Surgery 2026, Pancreas Injury Scale table; Lanier and Mellnick 2026, DOI 10.1177/08465371261424865, duct-imaging limitations; Coccolini et al. 2019, PMC6907251, management context."
}