Return a base type I-IV plus a Va/Vb overlay whenever type V applies. Keep preoperative suspicion separate from definitive wall-loss classification and use the result to communicate anatomy, not to order an operation.
{
"categories": [
{
"outcome_code": "I",
"mechanism": "extrinsic_bile_duct_compression",
"cholecystobiliary_fistula": "absent",
"bile_duct_wall_circumference_eroded": "none"
},
{
"outcome_code": "II",
"mechanism": "cholecystobiliary_fistula",
"bile_duct_wall_circumference_eroded": "less_than_or_up_to_one_third"
},
{
"outcome_code": "III",
"mechanism": "cholecystobiliary_fistula",
"bile_duct_wall_circumference_eroded": "more_than_one_third_and_up_to_two_thirds"
},
{
"outcome_code": "IV",
"mechanism": "cholecystobiliary_fistula",
"bile_duct_wall_circumference_eroded": "complete",
"anatomic_result": "complete_duct_wall_destruction_and_fusion_with_gallbladder"
},
{
"outcome_code": "Va",
"overlay": "any_underlying_type_I_to_IV_plus_cholecystoenteric_fistula",
"gallstone_ileus": "absent"
},
{
"outcome_code": "Vb",
"overlay": "any_underlying_type_I_to_IV_plus_cholecystoenteric_fistula",
"gallstone_ileus": "present"
}
],
"applicability": {
"use_for": "Anatomic description and procedural planning when an impacted gallstone causes extrinsic hepatic-duct or bile-duct compression, cholecystobiliary fistula, or a related cholecystoenteric fistula.",
"classification_unit": "one_Mirizzi_anatomic_complex_at_the_time_of_assessment",
"required_inputs": [
"impacted_stone_location",
"extrinsic_duct_compression",
"cholecystobiliary_fistula_presence",
"estimated_fraction_of_duct_wall_loss",
"cholecystoenteric_fistula_presence",
"gallstone_ileus_presence"
],
"outside_scope": [
"malignant_hilar_obstruction",
"isolated_choledocholithiasis_without_Mirizzi_mechanism",
"postoperative_bile_duct_injury_classification",
"treatment_selection_without_hepatobiliary_expertise"
]
},
"core_classification_algorithm": [
{
"if": "external_compression_without_cholecystobiliary_fistula",
"output_code": "I"
},
{
"if": "cholecystobiliary_fistula_with_wall_loss_not_exceeding_one_third",
"output_code": "II"
},
{
"if": "cholecystobiliary_fistula_with_wall_loss_more_than_one_third_and_not_exceeding_two_thirds",
"output_code": "III"
},
{
"if": "complete_circumferential_duct_wall_destruction",
"output_code": "IV"
}
],
"type_V_overlay_algorithm": {
"prerequisite": "A cholecystoenteric fistula coexists with an underlying Csendes I, II, III, or IV lesion.",
"without_bowel_obstruction_from_a_gallstone": "Va",
"with_gallstone_ileus": "Vb",
"mandatory_companion_output": "Always report the underlying I-IV anatomy when it can be established; Va or Vb alone discards the bile-duct-wall information needed for planning.",
"nonordinal_rule": "Type V is an overlay, not a simple severity step after IV. Va and Vb describe enteric fistula and ileus status while the underlying I-IV type describes the biliary defect."
},
"preoperative_assessment": {
"ultrasound": [
"impacted_infundibular_or_cystic_duct_stone",
"intrahepatic_or_common_hepatic_duct_dilatation",
"gallbladder_contraction_or_inflammation"
],
"MRCP_or_CT": [
"level_and_length_of_obstruction",
"stone_and_fistula_anatomy",
"biliary_confluence",
"adjacent_duodenum_stomach_or_colon",
"bowel_obstruction_and_ectopic_stone"
],
"ERCP_or_cholangiography_when_performed": [
"duct_lumen_and_filling_defect",
"stricture_or_fistula",
"distal_duct_patency",
"decompression_or_stent_context"
],
"certainty_rule": "Preoperative imaging can suggest the class, but exact circumferential wall loss is often established during cholangiography or surgery. Label an imaging-only class as suspected when the fistula or wall fraction is not directly demonstrated."
},
"operative_planning_implications_from_primary_series": {
"I": "The original series treated external compression without a duct-wall fistula differently from wall-loss lesions; anatomy must be clarified before dissection.",
"II": "A limited wall defect may permit repair or choledochoplasty in expert hands; the code does not mandate a single technique.",
"III": "The original series advised against simple fistula suture and favored choledochoplasty for the larger wall defect.",
"IV": "The original series preferred bilioenteric reconstruction for complete duct-wall destruction.",
"Va": "Plan for both the underlying biliary lesion and closure or management of the involved enteric organ; preserve the base I-IV type.",
"Vb": "Gallstone ileus adds bowel-obstruction management. The 2008 validation supports a staged strategy in selected patients, but timing and procedures remain individualized.",
"safety_rule": "These are anatomic planning implications from the source cohorts, not an autonomous operative prescription; current approach depends on physiology, inflammation, malignancy exclusion, local expertise and intraoperative anatomy."
},
"risk_model": {
"common_risks": [
"distorted_Calot_triangle_anatomy",
"bile_duct_injury",
"vascular_or_adjacent_organ_injury",
"residual_stone",
"biliary_leak_or_stricture",
"infection"
],
"severity_trend": "In the original 1989 cohort, operative morbidity and mortality increased with the extent of the cholecystobiliary lesion.",
"type_V_addition": "Cholecystoenteric fistula adds adjacent-organ involvement; Vb additionally identifies mechanical bowel obstruction from a gallstone.",
"nonquantitative_rule": "The class does not provide a validated patient-specific complication percentage or mortality calculator."
},
"differential_and_safety_checks": [
"Exclude cholangiocarcinoma or gallbladder malignancy when the obstruction, wall thickening, mass, nodes or clinical course are atypical.",
"Do not call Type I from duct dilatation alone; demonstrate or strongly support the impacted-stone compression mechanism.",
"Do not estimate a II-versus-III wall fraction from luminal narrowing alone when the fistula is not directly established.",
"Do not use Bismuth-Corlette, Strasberg or bile-leak injury categories as substitutes for the Csendes Mirizzi anatomy."
],
"output_contract": [
"suspected_or_confirmed_Mirizzi_mechanism",
"impacted_stone_location",
"level_of_biliary_obstruction_and_upstream_dilatation",
"cholecystobiliary_fistula_and_fraction_of_wall_loss",
"base_Csendes_code_I_to_IV",
"cholecystoenteric_fistula_and_involved_organ",
"Va_or_Vb_overlay_with_gallstone_ileus_status",
"certainty_and_modality",
"malignancy_or_alternative_diagnosis_warning",
"hepatobiliary_planning_flag_without_autonomous_surgery"
],
"missing_input_behavior": [
"If a fistula is suspected but circumferential wall loss is unknown, do not guess II, III or IV; report suspected cholecystobiliary fistula and request definitive delineation.",
"If a cholecystoenteric fistula is present but bowel-obstruction or ectopic-stone status is unknown, do not choose Va or Vb.",
"If Va or Vb is assigned but the underlying I-IV anatomy is unresolved, state that base type is indeterminate rather than treating V as a complete description.",
"If malignancy remains a credible better explanation, do not finalize Mirizzi type as the sole diagnosis."
],
"interpretation_limits": [
"Csendes is an anatomic surgical classification, not a radiology-only certainty score, treatment mandate or calibrated prognosis.",
"The I-IV thresholds refer to circumference of bile-duct wall loss, not longitudinal fistula length or percentage luminal stenosis."
],
"source_locator": "Csendes et al., Br J Surg 1989;76:1139-1143, PMID 2597969, DOI 10.1002/bjs.1800761110, abstract and original type-specific operative discussion; Beltran, Csendes and Cruces, World J Surg 2008;32:2237-2243, PMID 18587614, DOI 10.1007/s00268-008-9660-3, Table 1, Results and Discussion for type V, underlying anatomy, complications and gallstone-ileus strategy."
}