Original article Clinical endoscopy| Volume 97, ISSUE 2, P300-308, February 2023

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Novel classification system for walled-off necrosis: a step toward standardized nomenclature and risk-stratification framework

Published:October 05, 2022DOI:

      Background and Aims

      The optimal therapeutic approach for walled-off necrosis (WON) is not fully understood, given the lack of a validated classification system. We propose a novel and robust classification system based on radiologic and clinical factors to standardize the nomenclature, provide a framework to guide comparative effectiveness trials, and inform the optimal WON interventional approach.


      This was a retrospective analysis of patients who underwent endoscopic management of WON by lumen-apposing metal stent placement at a tertiary referral center. Patients were classified according to the proposed QNI classification system: quadrant (“Q”), represented an abdominal quadrant distribution; necrosis (“N”), denoted by the percentage of necrosis of WON; and infection (“I”), denoted as positive blood culture and/or systemic inflammatory response syndrome reaction with a positive WON culture. Two blinded reviewers classified all patients according to the QNI system. Patients were then divided into 2 groups: those with a lower QNI stratification (≤2 quadrants and ≤30% necrosis; group 1) and those with a higher stratification (≥3 quadrants, 2 quadrants with ≥30% necrosis, or 1 quadrant with >60% necrosis and infection; group 2). The primary outcome was mean time to WON resolution. Secondary procedural and clinical outcomes between the groups were compared.


      Seventy-one patients (75% men) were included and stratified by the QNI classification; group 1 comprised 17 patients and group 2, 54 patients. Patients in group 2 had a higher number of necrosectomies, longer hospital stays, and more readmissions. The mean time to resolution was longer in group 2 than in group 1 (79.6 ± 7.76 days vs 48.4 ± 9.22 days, P = .02). The mortality rate was higher in group 2 (15% vs 0%, P = .18).


      Despite the heterogeneous nature of WON in severe acute pancreatitis, a proposed QNI system may provide a standardized framework for WON classification to inform clinical trials, risk-stratify the disease course, and potentially inform an optimal management approach.

      Graphical abstract


      BISAP (Bedside Index for Severity in Acute Pancreatitis), ICU (intensive care unit), IQR (interquartile range), IR (interventional radiology), LAMS (lumen-apposing metal stent), QNI (quadrant, necrosis, infection), WON (walled-off necrosis)
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        • Peery A.F.
        • Crockett S.D.
        • Murphy C.C.
        • et al.
        Burden and cost of gastrointestinal, liver, and pancreatic diseases in the United States: update 2018.
        Gastroenterology. 2019; 156: 254-272
        • Garg S.K.
        • Sarvepalli S.
        • Campbell J.P.
        • et al.
        Incidence, admission rates, and predictors, and economic burden of adult emergency visits for acute pancreatitis: data from the National Emergency Department Sample, 2006 to 2012.
        J Clin Gastroenterol. 2019; 53: 220-225
        • Trikudanathan G.
        • Wolbrink D.R.J.
        • van Santvoort H.C.
        • et al.
        Current concepts in severe acute and necrotizing pancreatitis: an evidence-based approach.
        Gastroenterology. 2019; 156: 1994-2007
        • Banks P.A.
        • Bollen T.L.
        • Dervenis C.
        • et al.
        Classification of acute pancreatitis—2012: revision of the Atlanta classification and definitions by international consensus.
        Gut. 2013; 62: 102-111
        • van Santvoort H.C.
        • Besselink M.G.
        • Bakker O.J.
        • et al.
        A step-up approach or open necrosectomy for necrotizing pancreatitis.
        N Engl J Med. 2010; 362: 1491-1502
        • Hollemans R.A.
        • Bakker O.J.
        • Boermeester M.A.
        • et al.
        Superiority of step-up approach vs open necrosectomy in long-term follow-up of patients with necrotizing pancreatitis.
        Gastroenterology. 2019; 156: 1016-1026
        • Baron T.H.
        • DiMaio C.J.
        • Wang A.Y.
        • et al.
        American Gastroenterological Association clinical practice update: management of pancreatic necrosis.
        Gastroenterology. 2020; 158: 67-75
        • Lakhtakia S.
        • Basha J.
        • Talukdar R.
        • et al.
        Endoscopic "step-up approach" using a dedicated biflanged metal stent reduces the need for direct necrosectomy in walled-off necrosis (with videos).
        Gastrointest Endosc. 2017; 85: 1243-1252
        • Sharaiha R.Z.
        • Tyberg A.
        • Khashab M.A.
        • et al.
        Endoscopic therapy with lumen-apposing metal stents is safe and effective for patients with pancreatic walled-off necrosis.
        Clin Gastroenterol Hepatol. 2016; 14: 1797-1803
        • Abu Dayyeh B.K.
        • Topazian M.
        Endoscopic management of pancreatic necrosis.
        Am J Gastroenterol. 2018; 113: 1269-1273
        • Xu M.M.
        • Andalib I.
        • Novikov A.
        • et al.
        Endoscopic therapy for pancreatic fluid collections: a definitive management using a dedicated algorithm.
        Clin Endosc. 2020; 53: 355-360
        • Chandrasekhara V.
        • Elhanafi S.
        • Storm A.C.
        • et al.
        Predicting the need for step-up therapy after EUS-guided drainage of pancreatic fluid collections with lumen-apposing metal stents.
        Clin Gastroenterol Hepatol. 2021; 19: 2192-2198
      1. Working Group IAP/APA Acute Pancreatitis Guidelines. IAP/APA evidence-based guidelines for the management of acute pancreatitis.
        Pancreatology. 2013; 13: e1-e15
        • Coffin A.
        • Boulay-Coletta I.
        • Sebbag-Sfez D.
        • et al.
        Radioanatomy of the retroperitoneal space.
        Diagn Intervent Imaging. 2015; 96: 171-186
        • Garg P.K.
        • Madan K.
        • Pande G.K.
        • et al.
        Association of extent and infection of pancreatic necrosis with organ failure and death in acute necrotizing pancreatitis.
        Clin Gastroenterol Hepatol. 2005; 3: 159-166
        • Bollen T.L.
        Imaging of acute pancreatitis: update of the revised Atlanta classification.
        Radiol Clin North Am. 2012; 50: 429-445
        • Ranson J.H.
        • Rifkind K.M.
        • Roses D.F.
        • et al.
        Prognostic signs and the role of operative management in acute pancreatitis.
        Surg Gynecol Obstet. 1974; 139: 69-81
        • Knaus W.A.
        • Draper E.A.
        • Wagner D.P.
        • et al.
        APACHE II: a severity of disease classification system.
        Crit Care Med. 1985; 13: 818-829
        • Marshall J.C.
        • Cook D.J.
        • Christou N.V.
        • et al.
        Multiple organ dysfunction score: a reliable descriptor of a complex clinical outcome.
        Crit Care Med. 1995; 23: 1638-1652
        • Hamada T.
        • Yasunaga H.
        • Nakai Y.
        • et al.
        Japanese severity score for acute pancreatitis well predicts in-hospital mortality: a nationwide survey of 17,901 cases.
        J Gastroenterol. 2013; 48: 1384-1391
        • Bakker O.J.
        • van Santvoort H.C.
        • van Brunschot S.
        • et al.
        Endoscopic transgastric vs surgical necrosectomy for infected necrotizing pancreatitis: a randomized trial.
        JAMA. 2012; 307: 1053-1061
        • van Brunschot S.
        • Hollemans R.A.
        • Bakker O.J.
        • et al.
        Minimally invasive and endoscopic versus open necrosectomy for necrotising pancreatitis: a pooled analysis of individual data for 1980 patients.
        Gut. 2018; 67: 697-706
        • Bazerbachi F.
        • Sawas T.
        • Vargas E.J.
        • et al.
        Metal stents versus plastic stents for the management of pancreatic walled-off necrosis: a systematic review and meta-analysis.
        Gastrointest Endosc. 2018; 87: 30-42
        • Chandrasekhara V.
        • Barthet M.
        • Devière J.
        • et al.
        Safety and efficacy of lumen-apposing metal stents versus plastic stents to treat walled-off pancreatic necrosis: systematic review and meta-analysis.
        Endosc Int Open. 2020; 8: E1639-E1653
        • Luckhurst C.M.
        • El Hechi M.
        • Elsharkawy A.E.
        • et al.
        Improved mortality in necrotizing pancreatitis with a multidisciplinary minimally invasive step-up approach: comparison with a modern open necrosectomy cohort.
        J Am Coll Surg. 2020; 230: 873-883