PERCUTANEOUS CHOLANGIOSCOPY IN OBSTRUCTED BILIARY METAL STENTS

Purpose: To reevaluate the reasons for the occlusion of self-expanding biliary metal stents, on the basis of cholangioscopic findings. Metho ds: Percutaneous transhepatic cholangioscopy (PTCS) was performed in 1 5 patients with obstructed biliary Wallstents. The reason for stent in sertion was a malignant obstruction in 14 patients; 1 had a benign bil iary stricture. Conventional noncovered stents had been inserted in 12 patients; in 3 cases a polyurethane-covered prototype Wallstent had b een used. Stent occlusions occurred after 1-55 months. PTCS was perfor med with a 2.3-mm endoscope through an 11 Fr sheath. Biopsies were tak en via the working channel of the endoscope. Results: In all patients with noncovered stents the inner surface of the stent was highly irreg ular with seaweed-like protrusions (biopsy-proven granulation tissue). Stent incorporation varied from absent (n = 1) to subtotal (n = 8), b ut was always incomplete, no matter how long the stent had been in pla ce. Tumor ingrowth was histologically proven in 2 patients. One patien t had a large occluding concrement at the proximal end of the stent. I n patients with covered stents, the inner surface appeared more regula r; however, viable granulation tissue was found inside two stents and tumor ingrowth in one of them. Conclusion: PTCS showed that incorporat ion of the stent is virtually always incomplete. The factors contribut ing most to stent occlusion are the buildup of granulation tissue, bil e sludge, and tumor overgrowth. Stone formation and tumor ingrowth can also be important, although less common causes of occlusion. A polyur ethane stent covering could not prevent tumor ingrowth in one patient and the buildup of viable granulation tissue inside the stent in two f urther patients; mean stent patency in the three patients with such a stent was 3 months.