Percutaneous Endoscopic Necrosectomy (PEN): Is the PEN Mightier Than the VARD?

Abstract

Necrotizing pancreatitis, one of the most feared and morbid complications of acute pancreatitis (AP), is seen in 5–10% of AP patients [1]. Very often, necrotic collections get infected which warrants drainage and debridement. Infected necrosis, typically a late event in the natural course of AP, can occur early in a quarter of the patients [2]. Typically, this is managed conservatively with intravenous antibiotics as current guidelines recommend delaying invasive intervention for at least 4 weeks after initial presentation to allow the collection to become “walled off” [3]. Occasionally necrotizing pancreatitis with clear evidence of infection despite maximal medical support may warrant an earlier intervention for drainage and/or debridement [2]. The current paradigm for intervention in necrotizing pancreatitis involves a staged multi-disciplinary algorithmic step-up approach with endoscopic transluminal drainage (ETD) or percutaneous drainage (PCD) as the initial step based on the location of the necrotic collection and the availability of localized expertise [1, 3]. PCD is widely available and is the initial drainage procedure of choice, especially for necrotic collections that may not be readily amenable to ETD such as those that do not abut the lumen of the stomach and duodenum or that extend deeply into the retroperitoneum [4, 5]. In PCD, drainage of infected fluid under pressure temporizes septic complications, which further accelerates clinical improvement and enabling further encapsulation of necrotic collections [4]. Freeny et al. [5] reported complete resolution of sepsis in 47% of patients with infected necrosis after aggressive percutaneous drainage that required an average of four catheter insertions and lavage every 8 h for a mean of 85 days. In the landmark PANTER study, 35% of patients with infected necrosis recovered with antibiotic treatment and PCD as the sole therapeutic modality, with the caveat that solid necrotic tissue cannot be effectively evacuated via small caliber catheters. Large areas of necrosis, poor liquefaction, diffuse and multifocal collections, and the presence of multi-organ failure are factors that predict a poor response to PCD [6, 7] combined with the observation that when PCD was used alone, adverse events such as pancreatico-cutaneous fistulae were reported in up to 27% of patients [1]. Dual-modality drainage with concurrent endoscopic transluminal and percutaneous drainage was conceived in order to reduce rates of pancreatic and enteric fistulae [8]. While lavage through the percutaneous catheter with egress through the transmural fistula facilitates removal of liquefied necrotic material, solid necrotic material often requires direct debridement for complete resolution. Various forms of minimally invasive retroperitoneal necrosectomy techniques, such as video-assisted retroperitoneal debridement (VARD), and debridement using a nephroscope or mediastinoscope have been described [9]. VARD, which requires a 5–7-cm flank incision for insertion of a laparoscope, an irrigation catheter, and open surgical forceps, was recently compared to an endoscopic transluminal approach in a randomized trial (TENSION study) and had increased rates of pancreatic fistulae and increased lengths of stay [7]. All of the above instruments (laparoscope, nephroscope, and mediastinoscope) are rigid, limiting maneuverability around vital structures and penetration into deep recesses. Percutaneous endoscopic necrosectomy (often referred to as sinus tract endoscopy) using flexible endoscopy was pioneered as a technique which utilizes the existing percutaneous tract to facilitate retroperitoneal necrosectomy using instrumentation established for endoscopic transluminal necrosectomy [10]. The angulation and versatility offered by the flexible endoscope make it particularly convenient to access various extensions deep within the retroperitoneum. Although when initially described, this procedure was performed under general anesthesia, Dhingra et al. [11] * Guru Trikudanathan [email protected]