**3. Percutaneous and endoscopic interventions**

Although percutaneous and endoscopic interventions have historically been considered temporizing measures, not definitive management, many patients with pancreatic necrosis are successfully treated with these techniques, without need for more invasive therapy. Percutaneous drainage can successfully treat acute necrotizing pancreatitis in more than 50% of patients without need for surgical necrosectomy. The success rate with endoscopic therapy can reach 80% when used in conjunction with DEN [18, 19]. Thus, development of less invasive methods for addressing pancreatic necrosis led to a decrease in the indications for surgical intervention. The choice of intervention, percutaneous or endoscopic, is dependent on the situation, timing, and accessibility of the area of necrosis (**Figure 1**).

Endoscopic management of pancreatic necrosis is performed transmurally, either across the duodenum, for pancreatic head necrosis, or the stomach, for neck or body necrosis. Although technically feasible earlier in the clinical course, endoscopic intervention should be delayed to 4 weeks after onset of symptoms in order for an appropriate capsule to form around the necrotic tissue [20]. In cases where intervention can be delayed until WON form, and the WON is accessible transmurally, this is considered first-line intervention [18].

With or without the aid of endoscopic ultrasound (EUS), a plastic or selfexpanding metal stent (SEMS) is placed from the lumen of the duodenum or stomach into the area of WON. In addition to allowing the WON to drain into the

### **Figure 1.**

*Flowchart for Management of Pancreatic Necrosis after Failure of conservative management. After failure of conservative management – Supportive care, antibiotics, and nutrition – The appropriate intervention depends on the nature of the necrosis. If it is associated with a disconnected duct, a separate pathway, which ends with distal pancreatectomy, internal drainage, or endoscopic translumenal stent placement, is indicated. If there is no disconnected duct, the correct pathway is dictated by the stage of necrosis, as a nonencapsulated acute necrotic collection or as walled off necrosis. Endoscopic and percutaneous strategies are preferred in each situation, and traditional, laparoscopic or open necrosectomy serves as the final option for patients that fail other management, or in hospitals without resources or staff to perform other procedures.*

lumen, these stents also allow access to the area for debridement, via irrigation or DEN [21] (**Figure 2**). In DEN, an endoscope with one or two working ports is advanced through the previously placed, transluminal stent. Upon entering the WON, a number of tools, including forceps and snares are used to remove debris that would otherwise not be susceptible to removal with irrigation [21]. On average, 3–6 endoscopic interventions are necessary prior to resolution of necrosis [22].

DEN was first compared to surgical necrosectomy in the Pancreatitis, Endoscopic Transgastric vs. Primary Necrosectomy in Patients with Infected Necrosis (PENQUIN) Trial. In this trial, patients in the surgery group underwent a number of different operations, including 6 video-assisted retroperitoneal debridement (VARD) surgeries, 4 open necrosectomies, and 2 percutaneous drainage placements without need for more invasive therapy. The two patient who did not have a necrosectomy were excluded from final statistical analysis. All 10 patients in the endoscopic group had ultrasound guided stent placement, irrigation, and DEN. Following intervention, the rates of new-onset organ failure and pancreatic fistula were lower in the endoscopic group. The trial also compared the groups with regard to a composite clinical outcome, which included major post-operative complications and mortality, and found a lower rate in the endoscopic group [23, 24]. These findings were later replicated in the Minimallyinvasive Surgery Versus Endoscopy Randomized (MISER) Trial. Additionally, MISER showed lower rates of pancreatic fistula formation and a higher quality of life at 3 months after surgery in the endoscopic group [25]. In the Transluminal Endoscopic Step-up Approach Versus Minimally-invasive Surgical Step-up Approach in Patients with Infected Necrotizing Pancreatitis (TENSION) Trial, a larger randomized trial, no difference in mortality was observed. However, the rates of pancreatic fistula and length of stay favored the endoscopic group [26].

Percutaneous drainage is preferable in patients that are deemed too unstable to tolerate endoscopic drainage or if the area of necrosis extends into a dependent

### **Figure 2.**

*Surgical approaches to Necrosectomy. Access the lesser sac and retroperitoneum for the purposes of pancreatic necrosectomy can be achieve through a number of approaches. Direct endoscopic necrosectomy (DEN) is performed by accessing the stomach via the esophagus and then creating a posterior gastrotomy. The transgastric approach, performed laparoscopically or open, requires both an anterior and a posterior gastrotomy. The lesser sac can also be accessed by opening the gastrocolic ligament or transverse mesocolon, either by traversing a previously established, drainage tract or with a surgical approach.*

### *Surgical Management of Necrotizing Pancreatitis DOI: http://dx.doi.org/10.5772/intechopen.96044*

space, such as the paracolic gutters or pelvis. It is also an acceptable alternative when endoscopic drainage is unavailable or not technically feasible, specifically in the setting of ANC, when there is no capsule that could support an endoscopic stent [27].

Percutaneous drainage is usually CT-guided, although ultrasound-guided drainage can also be performed. These drains may be transperitoneal, with the external portion of the drain fixed in the anterior abdominal wall. These drains may also be placed through the flank, directly into the retroperitoneum, without traversing the peritoneum. In addition to draining ANC and WON, percutaneous drains can also be used for irrigation [28].

Although percutaneous drainage is successful as monotherapy in some patients, patients with larger areas of necrosis, multifocal necrosis, incomplete liquefaction, and pre-procedural organ failure are less likely to be adequately treated. While some of these factors can be overcome with larger drainage catheters, for these reasons, percutaneous drainage remains a bridge to therapy, allowing patients to survive the acute period of disease, and undergo definitive management later, with improved outcomes [26, 29, 30].
