Covered stents versus uncovered stents for the palliation of malignant extrahepatic biliary obstruction caused by direct tumor invasion: a cohort comparative study.

Biliary stenting is a well-established palliative treatment in patients with unresectable malignant biliary strictures. The aim of the present study was to compare clinical outcomes of covered and uncovered stents in patients with malignant extrahepatic biliary obstruction caused by direct tumor invasion. Patients diagnosed with malignant extrahepatic biliary obstruction caused by direct tumor invasion were enrolled in this study. Of these patients, 37 received ePTFE-covered stent placement and were prospectively studied, and 47 received uncovered stent placement and were retrospectively studied. The technical success rate, tumor ingrowth rate, complication rate, stent patency, and patient survival were evaluated for both groups. Stent placement was successful in all cases except one in the covered group due to stent kinking. Tumor ingrowth occurred exclusively in the uncovered group. No significant differences were observed for the complication rate and patient survival between the two groups. Three patients in the covered group experienced stent migration, whereas no patients did in the uncovered group. A significant difference was found regarding stent patency, which was greater for the covered group compared to the uncovered group. The placement of ePTFE-covered stents for the treatment of malignant biliary obstruction caused by direct tumor invasion was a safe and an effective method characterized by greater stent patency.