POLYETHYLENE PANCREATIC DUCT STENT-INDUCED CHANGES IN THE NORMAL DOG PANCREAS

This study was undertaken to evaluate the frequency, severity, and rev ersibility of stent-induced pancreatic ductal and parenchymal changes in the normal dog pancreas. Six adult mongrel dogs underwent duodenoto my and placement of 5F polyethylene pancreatic duct stents into the ma in pancreatic duct. After 8 weeks of stenting, the animals were random ly assigned to one of three groups: group I (n = 2), sacrifice; group II (n = 2), stent removal followed by sacrifice after an 8-week recove ry period; group III (n = 2), the stent was exchanged and kept in plac e for an additional 8 weeks. In group III at 16 weeks the stent was re moved, and the animals were allowed to recover for 8 weeks before sacr ifice. Pancreatograms were obtained at each operation and were normal before stent placement. Gross and histologic evaluation was performed at the time of sacrifice. All stented animals developed radiographic, gross, and histologic abnormalities. Pancreatograms showed duct dilati on in the stented region associated with a short stenosis at the mid t o upstream segment of the stent. Group III animals had more advanced r adiographic changes than group I and II animals. The radiographic find ings were associated with gross evidence of fibrosis, which increased proportionately with the length of the stenting period. Group III anim als developed moderate to severe pancreas atrophy. Histologic changes of obstructive pancreatitis were present in most experimental dogs. Th e results of this study suggest that pancreatic stenting may cause per manent damage in the normal dog pancreas. The cause of the damage appe ars to be related to stent occlusion, perhaps exacerbated by local ste nt-induced trauma.