Morphological features and not the timing determines the outcome of endoscopic ultrasound-guided transmural drainage of walled-off necrosis

10.1055/a-2654-4317

We read with great interest the study entitled “Encapsulation levels rather than elapsed time after the onset of acute pancreatitis are related to clinical outcomes of pancreatic walled-off necrosis” by Maruta et al. [1]. The authors defined wall maturation of walled-off necrosis (WON) on preprocedural computed tomography (CT) scans as a discrete, enhanced margin of ≥1 mm, with complete encapsulation being ≥80% maturation and partial/no encapsulation <80%. CT-based estimation of encapsulation percentage is however not standardized, and no method with high interobserver agreement currently exists. Assessment by a single observer is therefore vulnerable to bias and limited accuracy. In our opinion, the development of pneumoperitoneum or pneumoretroperitoneum after endoscopic transmural drainage remains the most definitive indicator of incomplete encapsulation, as these complications occur predominantly in such cases. Therefore, it would be interesting to know the incidence of pneumoperitoneum and pneumoretroperitoneum following the endoscopic ultrasound (EUS)-guided drainage in this cohort.

We agree with the authors’ conclusion that the degree of encapsulation is more closely associated with the clinical outcomes of EUS-guided treatment of WON than the time elapsed since disease onset. We have previously reported that collections with a well-formed encapsulating wall have better outcomes compared with WON exhibiting incomplete encapsulation [2] [3]. In addition to encapsulation, the amount of solid necrotic debris is another key determinant of transmural drainage outcomes [4]. It would therefore also be of interest to know the solid necrotic content in the encapsulated versus non-encapsulated collections in this cohort.

Publication History

Article published online:
27 November 2025

• References

• 1 Maruta A, Iwashita T, Saito T. et al. Encapsulation levels rather than elapsed time after the onset of acute pancreatitis are related to clinical outcomes of pancreatic walled-off necrosis. Endoscopy 2025;
• 2 Rana SS, Sharma R, Kishore K. et al. Safety and efficacy of early (<4 weeks of illness) endoscopic transmural drainage of post-acute pancreatic necrosis predominantly located in the body of the pancreas. J Gastrointest Surg 2021; 25: 2328-2335
• 3 Bharath PN, Rana SS. Early endoscopic interventions for pancreatic necrosis: indications, technique, and outcomes. Dig Dis Sci 2024; 69: 1571-1582
• 4 Rana SS, Bhasin DK, Sharma RK. et al. Do the morphological features of walled off pancreatic necrosis on endoscopic ultrasound determine the outcome of endoscopic transmural drainage?. Endosc Ultrasound 2014; 3: 118-122