Experimental study of the histocompatibility of covered expandable metallic stents in the trachea.
OBJECTIVE
To evaluate the histocompatibility of four different materials used to cover expandable metallic stents.


METHODS
Prospective, randomized, unblinded study.


METHODS
Animal research laboratory of Kurume University.


METHODS
Twenty 12- to 18-kg mongrel dogs.


METHODS
Handmade Gianturco-type stents with six bends, 20 mm in length, and 15 to 20 mm in diameter were covered using four different materials: polypropylene mesh, silicone-coated mesh, polyester mesh, and ePTFE. Covered stents were inserted into the trachea after i.v. anesthesia. Five animals were used in each group.


RESULTS
Postinsertion status was observed using clinical and bronchoscopy measures 7, 14, 28, and 56 days after intervention. Eight weeks after stent insertion, the tracheal specimens were studied pathologically. A scoring system was used to evaluate the histocompatibility of covered stents in each study group. The mean of clinical scores in the 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.
The Department of Surgery, Kurume University, School of Medicine, Fukuoka, Japan.
M
M
Mitsuoka
A
A
Hayashi
S
S
Takamori
K
K
Tayama
K
K
Shirouzu
D000771:Anesthesia, Intravenous; D000818:Animals; D001672:Biocompatible Materials / Q000009:adverse effects; D001999:Bronchoscopy; D003371:Cough / Q000209:etiology; D004285:Dogs; D004848:Epithelium / Q000473:pathology; D004867:Equipment Design; D006097:Granulation Tissue / Q000473:pathology; D006470:Hemorrhage / Q000209:etiology; D006648:Histocompatibility; D007442:Intubation, Intratracheal; D011091:Polyesters / Q000009:adverse effects; D011126:Polypropylenes / Q000009:adverse effects; D011138:Polytetrafluoroethylene / Q000009:adverse effects; D011446:Prospective Studies; D011897:Random Allocation; D012828:Silicones / Q000009:adverse effects; D013183:Sputum; D013193:Stainless Steel; D015607:Stents / Q000009:adverse effects; D013499:Surface Properties; D013526:Surgical Mesh; D014132:Trachea; D014136:Tracheitis / Q000209:etiology
D001672:Biocompatible Materials; D011091:Polyesters; D011126:Polypropylenes; D012828:Silicones; D013193:Stainless Steel; D011138:Polytetrafluoroethylene