Endoscopic Management of Pancreatic Pseudocysts

The crucial anatomic fact that makes endoscopic drainage of pseudocysts feasible is that a pseudocyst does not have its own structure; rather, it is a space delineated by the normal anatomic structures adjacent to the inflammatory process—the stomach, intestine, liver, spleen, or transverse mesocolon. The wall of the stomach or the duodenum is a common wall of the pseudocyst between which a thick inflammatory peel forms a poorly defined interface. This allows an enterostomy to be performed without concern for a potential space between the pseudocyst and the stomach or duodenum, which could develop if the pseudocyst and digestive walls were simply in close apposition.

As with many therapeutic endoscopic procedures, the initial attempts at endoscopic management were made in patients who were poor candidates for standard surgical intervention. Rogers et al¹⁸ provided one of the earliest descriptions of endoscopic cyst fluid aspiration from a 10-cm bulge on the posterior wall of the stomach. Although the cyst rapidly recurred, other case reports described additional endoscopic approaches. In 1982, Aranha et al¹ described their attempts at endoscopic cyst gastrostomy in two patients whose clinical course was complicated by a myocardial infarction and bleeding, respectively. Subsequently, Khawaja and Goldman¹⁴ and Kozarek et al¹⁶ reported successful attempts at endoscopic drainage, and many similar reports have followed.

Initial endoscopic attempts involved the creation of a fistula between the digestive tract and the pseudocyst, mimicking the surgical cyst enterostomy. This typically was accomplished by puncturing the cyst with a needle knife sphincterotome (i.e., a straight wire protruding from a catheter through which cautery current is passed) and then enlarging the fistula with a standard sphincterotome. Rapid closure of the fistula resulted in high failure rates and led to the widespread use of stents and nasocystic drains to maintain drainage through the enterostomy. The fact that 80% of pancreatic pseudocysts communicate with the pancreatic duct led Hershfield¹¹ to perform the first successful transpapillary drainage. In this report, he describes placing a pancreatic stent across the papilla and into the pancreatic duct, facilitating drainage by a more physiologic route. To date, numerous reports of combination transmural and transpapillary methods have been published. In addition, several hundred procedures have now been reported as investigators attempt to delineate the optimal approach to various situations.