EXPERIMENTAL-STUDY OF THE HISTOCOMPATIBILITY OF COVERED EXPANDABLE METALLIC STENTS IN THE TRACHEA

Study objectives; To evaluate the histocompatibility of four different materials used to cover expandable metallic stents. Design: Prospecti ve, randomized, unblinded study, Setting: Animal research laboratory o f Kurume University. Patients or participants: Twenty 12- to 18-kg mon grel dogs. Interventions: Handmade Gianturco-type stents with six bend s, 20 mm in length, and 15 to 20 mm in diameter were covered using fou r different materials: polypropylene mesh, silicone-coated mesh, polye ster mesh, and ePTFE, Covered stents were inserted into the trachea af ter IV anesthesia, Five animals were used in each group. Measurements and results: Postinsertion status was observed using clinical and bron choscopy measures 7, 14, 28, and 56 days after intervention. Fight wee ks after stent insertion, the tracheal specimens were studied patholog ically. A scoring system was used to evaluate the histocompatibility o f covered stents in each study group. The mean of clinical scores in t he polypropylene group was 1.84+/-0.36, which was significantly higher than those in the groups of silicone, polyester, and ePTFE, The means of histopathologic scores in the polypropylene group and the silicone group were 1.60+/-0.55, which were significantly higher than those in groups of polyester and ePTFE, Conclusions: Polypropylene mesh cover was more suitable than silicone-coated mesh, polyester mesh, and ePTFE because of its excellent histocompatibility.