clavien_atlas_of_upper_gastrointestinal_and_hepato-pancreato-biliary_surgery2007-10-01_3540200045_springer

Necrosectomy

Waldemar Uhl, Oliver Strobel, Markus W. Buchler (Open Necrosectomy with Closed Postoperative Lavage),

Carlos Fernández-del Castillo (Necrosectomy and Closed Packing), Gregory G. Tsiotos, Michael G. Sarr (Planned Repeated Necrosectomy), C. Ross Carter, Clement W. Imrie (Percutaneous Necrosectomy)

Introduction

Severe acute pancreatitis remains a life-threatening disease. The first phase (about 10–14days) is characterized by formation of pancreatic and peripancreatic necrosis and development of a systemic inflammatory response syndrome. This systemic response to the pancreatic inflammation/necrosis causes early organ failure that necessitates intensive care therapy. In the second phase (after 2weeks), the leading cause of morbidity and mortality is superinfection of necrosis with development of septic multiple organ failure. In the last 2decades, treatment has evolved considerably, and with improved intensive care management, there is a worldwide trend toward a more conservative strategy with operative intervention initiated primarily because of the local and systemic manifestations of infected necrosis and less so for sterile necrosis. However, today, septic complications caused by pancreatic infection account for 80% of the mortality, and infected necrosis therefore usually remains an absolute indication for same form of invasive intervention.

The goals of operative necrosectomy are to remove the necrotic and infected tissue and to minimize injury to viable tissues. In addition, each technique described below also aims to minimize the accumulation of exudative fluid and extravasated pancreatic exocrine secretions from the operative bed, because if undrained, infection invariably occurs.

This section will discuss four operative techniques of necrosectomy and drainage. All have similarities in their ultimate goal of complete debridement of necrotic tissue, but all tend to achieve this goal differently. Indeed, individual patients may be best treated selectively.

Indications and Contraindications

Preoperative Investigation and Preparation for Procedure

■The diagnosis of acute pancreatitis is one of exclusion (exclude other surgical conditions) based on history, physical examination, and biochemistry.

■Initial assessment and continuous intensive care unit monitoring of severity (APACHE-II score).

■Laboratory assessment – CBC and electrolytes, liver function tests, and coagulation profile; some groups utilize serum C-reactive protein as a diagnostic/prognostic guide.

■Cardiovascular, respiratory, and metabolic resuscitation; aggressive management of SIRS for the first 10–14days of acute pancreatitis.

■Contrast-enhanced dynamic CT about 1week from onset of acute pancreatitis to assess the presence and extent of pancreatic and/or peripancreatic tissue necrosis, as well as extraluminal retroperitoneal gas.

■Early “prophylactic” administration of appropriate antibiotics (Imipenem) to prevent pancreatic superinfection from the gut is adopted by most, but not all, surgeons;

use of oral antifungal agents is favored.

■Initiation of parenteral nutrition with early conversion to intrajejunal feeding (using a nasojejunal tube with its tip distal to the fourth portion of the duodenum); if possible, intragastric feeding may be effective.

■In severe gallstone pancreatitis, if choledocholithiasis is present, early endoscopic sphincterotomy and stone removal decreases morbidity and mortality.

■When operation is planned, the preoperative CT serves as the “road map” for necrosectomy to delineate all fluid collections in areas remote from the pancreas, especially for the retroperitoneal paracolic gutters and perinephric spaces.

Caution is necessary because of inflammatory adhesions between the pancreas, transverse mesocolon, and posterior wall of the stomach.

The pancreatic area is fully exposed; necrotic areas are darker and more woodyfeeling than viable tissue.

Necrosis is usually not limited to the pancreas but also involves the peripancreatic and retroperitoneal fatty tissue as well; pancreatic parenchymal necrosis is usually patchy and superficial with deeper parts of the pancreas still perfused and viable (A-2).

A-2

A careful blunt technique removes devitalized tissue and preserves the viable pancreatic parenchyma.

Bleeding from the pancreas is controlled by transfixion sutures using nonabsorbable, monofilament suture material.

The spleen is usually not involved specifically in the necrotic process, and thus the need for splenectomy should be very rare.

Gastrocolic and duodenocolic ligaments are re-sutured together to create a closed peripancreatic compartment to allow for contained postoperative lavage of the lesser sac and involved retroperitoneum.

With marked mesoand retrocolic necrosis threatening the viability of the transverse colon, a diverting ileostomy is created in

the right lower quadrant.

Debridement and removal of the necrotic tissue (necrosectomy) is done bluntly with the fingers or with a sponge. It is important to break into all the recesses of the cavity as guided by the CT to thoroughly remove the debris and necrotic material, a sample of which should also be sent to bacteriology. Any firm attachments should be clamped and tied or left alone.

The pancreas can be discerned from peripancreatic tissues often only on the basis of its location and consistency. Resection of the pancreas should be done carefully and only if the CT shows pancreatic parenchymal necrosis.

If necrosis extends deep into the perirenal spaces and this cannot be accessed through the mesocolon, the respective paracolic gutters are opened to remove the debris/necrosis.

After completing the necrosectomy/debridement, the pancreatic bed is irrigated with several liters of normal saline.