Intervention is indicated in patients with infected necrotizing pancreatitis and clinical signs of infection or sepsis. The minimally invasive step-up approach is applicable in nearly all patients and has been shown to be superior to primary open necrosectomy in terms of major morbidity including postprocedural organ failure. The step-up approach consists of percutaneous catheter drainage as a first step followed by video-assisted retroperitoneal debridement (VARD) when needed.
Infection of necrotizing pancreatitis is typically diagnosed a few weeks after onset of acute pancreatitis. It is preferred to postpone any intervention until after 4 weeks following onset of disease, as this reduces postoperative morbidity. During this period, using antibiotics and intensive care, the condition of the patient is allowed to improve and the collections become encapsulated and walled-off. “Walled-off pancreatic necrosis” (WOPN) reduces the risk of bleeding during necrosectomy.
Clinical signs of infection or sepsis are important for determining the need for intervention. Only a small (approximately 5%) subset of patients with infected necrotizing pancreatitis but without signs of sepsis can be treated with antibiotics alone. Computed tomography (CT) depicts bacteria related gas bubbles in only 50% of patients with infected necrotizing pancreatitis. Absence of gas bubbles certainly does not exclude infection. Fine-needle aspiration (FNA) is advised by some surgeons but one should keep in mind that FNA is associated with false-negative test results up to 50%. Sterile necrotizing pancreatitis only rarely requires intervention.
A high-quality contrast-enhanced CT scan is performed to determine the size and position of the collection(s) of infected necrosis and accessibility for percutaneous drains. The CT scan should be viewed with an intent to determine the relationship of the left side of the collection to the left abdominal wall just over Gerota fascia and whether there are any paracolic extensions of the infected collection (Figure 1). In 95% of patients percutaneous drainage is feasible.
For the VARD procedure, the collection should be within reach of a percutaneous drain placed through the retroperitoneum, which is the case in more than 80% of patients. Typically, this drain is placed over Gerota fascia of the left kidney. Some 30% of patients do not require a VARD procedure and can be successfully treated with one or two 12 to 20 French percutaneous drains. After percutaneous drain placement, drains should be flushed three times daily with 50 mL saline each time to prevent blockage of the drain and to promote lavage of the cavity. The patient should be observed for about 3 days, and if the condition does not improve, a repeat CT is performed to check that the drains are in good position within the collection. If the size of the collection is not significantly improved after 1 to 2 weeks of percutaneous drainage, the next step, VARD, ...