title: Mechanical properties of different airway stents.
abstract: Airway stents improve pulmonary function and quality of life in patients suffering from airway obstruction. The aim of this study was to compare main types of stents (silicone, balloon-dilated metal, self-expanding metal, and covered self-expanding metal) in terms of their mechanical properties and the radial forces they exert on the trachea. Mechanical measurements were carried out using a force gauge and specially designed adaptors fabricated in our lab. Numerical simulations were performed for eight different stent geometries, inserted into trachea models. The results show a clear correlation between stent diameter (oversizing) and the levels of stress it exerts on the trachea. Compared with uncovered metal stents, metal stents that are covered with less stiff material exert significantly less stress on the trachea while still maintaining strong contact with it. The use of such stents may reduce formation of mucosa necrosis and fistulas while still preventing stent migration. Silicone stents produce the lowest levels of stress, which may be due to weak contact between the stent and the trachea and can explain their propensity for migration. Unexpectedly, stents made of the same materials exerted different stresses due to differences in their structure. Stenosis significantly increases stress levels in all stents.
authors.affiliation: Afeka, Tel-Aviv Academic College of Engineering, Medical Engineering Department, Tel Aviv 69107, Israel. Electronic address: ratnovskya@afeka.ac.il.
authors.forename: Anat
authors.initials: A
authors.lastname: Ratnovsky
authors.affiliation: Afeka, Tel-Aviv Academic College of Engineering, Medical Engineering Department, Tel Aviv 69107, Israel.
authors.forename: Noa
authors.initials: N
authors.lastname: Regev
authors.affiliation: Afeka, Tel-Aviv Academic College of Engineering, Medical Engineering Department, Tel Aviv 69107, Israel.
authors.forename: Shaily
authors.initials: S
authors.lastname: Wald
authors.affiliation: Rabin Medical Center, Pulmonary Institute, Petach Tikva, Israel.
authors.forename: Mordechai
authors.initials: M
authors.lastname: Kramer
authors.affiliation: Afeka, Tel-Aviv Academic College of Engineering, Medical Engineering Department, Tel Aviv 69107, Israel.
authors.forename: Sara
authors.initials: S
authors.lastname: Naftali
mesh_terms: D003198:Computer Simulation; D006801:Humans; D008422:Materials Testing; D008670:Metals; D008962:Models, Theoretical; D011474:Prosthesis Design; D012828:Silicones; D015607:Stents; D013312:Stress, Physiological; D014132:Trachea / Q000503:physiopathology; D014135:Tracheal Stenosis / Q000503:physiopathology / Q000628:therapy
chemical_list: D008670:Metals; D012828:Silicones
keywords: Airway; Airway obstruction; Numerical simulation; Stent; Stress