Whether clean or dirty, endoscopic treatment is recommended for symptomatic walled-off necrosis

Walled-off necrosis (WON) is one of the stages in acute pancreatitis that develops weeks after the incidence of pancreatic and/or peripancreatic necrosis. WON is documented by cross-sectional imaging [1]. Typically, WON can be categorized into asymptomatic and symptomatic WON. Many small asymptomatic WONs may spontaneously resolve with conservative management, without the need for intervention. The most common presentation of symptomatic WON is infection. Cross-sectional imaging may show air bubbles inside the WON cavity. In cases with no air bubbles on cross-sectional imaging, a fine-needle aspiration from the WON may be needed to confirm bacterial contamination. In general, patients with infected WON show a wide clinical spectrum on presentation, ranging from uncontrolled fever to more severe cases with sepsis. Infected WON may herald spontaneous rupture either to the gastrointestinal lumen or to the skin [2]. The prognosis for spontaneously ruptured WON is unpredictable and could be fatal if the ruptured site is in the colon [3]. Therefore, drainage and/or necrosectomy either surgically or nonsurgically is recommended to avoid rupture of the infected WON [2] [4] [5].

“This series has revealed that endoscopic treatment is indicated not only for infected WON but also for the management of symptomatic sterile WON.”

The majority of patients with sterile WON present with no or fewer symptoms compared with patients with infected WON [5] [6]. In addition, many of them do well with conservative treatment [4] [5]. Moreover, the overall length of hospital stay and the need for intensive care unit admission are much lower than for patients with infected WON [2]. However, a significant number of patients with sterile WON have a very slow course of improvement and the appropriate treatment for these patients is still a subject of debate. Many unresolved issues include the waiting time before initiation of drainage, the choice of drainage, and the need for step-up treatment.

In the current issue of Endoscopy, Boxhoorn et al. report on a study from two large medical centers in the Netherlands, which recruited the largest number of symptomatic sterile WON patients over 20 years [7]. Patients first underwent endoscopic transluminal drainage (ETD), with a subsequent step-up approach plan if needed. However, the majority of the patients (73 %) eventually required endoscopic transluminal necrosectomy (ETN), with a median of 2 ETN procedures being performed due to clinically relevant post-procedural infection.

What have we learned from this series? First, I admire the authors for their patience on waiting for almost 7 months (129 – 343 days) before they initiated ETD in this cohort. Unlike the patients with infected WON, who usually have persistent fever or uncontrolled infection as the indication for ETD, the majority of patients with sterile WON underwent ETD because of uncontrolled or prolonged pain and others received ETD because of symptoms related to gastrointestinal tract obstruction such as obstructive jaundice and gastric outlet obstruction. Unfortunately, there is no recommendation on the maximum duration of conservative treatment before deciding on an intervention. I imagine that the pain management, which included opioid administration, for this length of time was not easy.

The second point that we have learned is that when ETD is offered, the team should be ready for the subsequent ETN and this might require backup from additional interventions such as percutaneous catheter drainage, ETN, and video-assisted retroperitoneal debridement. Thus, this high threshold for initiation of ETD could prevent unnecessary ETD that may subsequently require ETN or other advanced treatments.

The third point is that the amount of necrosis could determine the risk for clinically relevant post-procedural infection. In the univariate analysis, as well as nasocystic catheter placement being found to be associated with the risk of infection, ≥ 30 % necrosis within the WON was also considered a risk. Notably, the authors point out that nasocystic catheter placement was a common feature in patients with large amounts of necrosis. Given the more recent use of lumen-apposing metal stents (LAMS), which are now widely available, perhaps LAMS placement during the initial ETD in patients with ≥ 30 % necrosis within the WON may reduce the need for future endoscopic sessions. Although statistically insignificant in this series, the authors found that the number of LAMS placement was higher in those who did not develop post-procedural infection than in those with infection (27 % vs. 7 %).

This series has revealed that endoscopic treatment is indicated not only for infected WON but also for the management of symptomatic sterile WON. In my view, whether the WON is clean or dirty, endoscopic treatment is indicated for symptomatic WON following an adequate waiting time, and once ETD is initiated, the team should be ready for multiple rounds of endoscopic and/or interventional treatments including step-up ETN and the percutaneous approach.

Publication History

Article published online:
27 January 2021

• References

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