Tracheal diseases such as tracheal stenosis and tracheomalacia often have a significant impact on patients’ respiratory function. Traditional tracheal stents face issues such as displacement, granulation tissue hyperplasia, and axial foreshortening during clinical use, which limit their long-term efficacy. The mechanical behavior of auxetic tracheal stents was studied, focusing on the impact of design parameters on stent performance. Finite element analysis was used to assess the effects of different unit cell strut geometries (including connecting strut shape and unit cell core design) on the stent’s stress-strain behavior, expansion performance, and anti-migration properties. The results show that the curved design stent exhibits a nonlinear stress-strain relationship similar to that of the trachea. The multi-circular core design demonstrated the best overall performance, with a radial recoil rate of 6.6% and a maximum anti-migration force of 641 N, representing a 51% improvement over the straight-bar stent. The multi-circular design significantly reduces the risk of granulation tissue formation through uniform stress distribution (maximum principal stress of 136 MPa) and low tracheal wall stress (0.24 MPa), making it a promising candidate for long-term implantation. This study provides theoretical support for the optimization of tracheal stent designs and lays the foundation for the long-term implantation of auxetic tracheal stents in the future.
JamilAStillSSchwartzGS, et al. Tracheal resection for tracheal stenosis. Proc2020; 33: 15–18.
2.
LiuCHHuangWSWangHH, et al. Airway obstruction due to tracheomalacia caused by innominate artery compression and a kyphotic cervical spine. Ann Thorac Surg2015; 99: 685–687.
3.
KhoaNDPhuongNLTaniK, et al. Computational fluid dynamics comparison of impaired breathing function in French bulldogs with nostril stenosis and an examination of the efficacy of rhinoplasty. Comput Biol Med2021; 134: 104398.
4.
PejhanSJavaherzadehMDaneshvarA, et al. A safe method of tracheal polyflex stent placement: a review of 20 patients. Iran Red Crescent Med J2015; 17: e13798.
5.
PlojouxJLaroumagneSVandemoorteleT, et al. Management of benign dynamic “A-shape” tracheal stenosis: a retrospective study of 60 patients. Ann Thorac Surg2015; 99: 447–453.
6.
HuangJZhangZZhangT.Suture fixation of tracheal stents for the treatment of upper trachea stenosis: a retrospective study. J Cardiothorac Surg2018; 13: 111.
BarghouthyYWisemanOVentimigliaE, et al. Silicone-hydrocoated ureteral stents encrustation and biofilm formation after 3-week dwell time: results of a prospective randomized multicenter clinical study. World J Urol2021; 39: 3623–3629.
9.
ImaniSMAboutalebiMATafazzoli-ShadpourM, et al. Analysis of the stent expansion in a stenosed artery using finite element method: application to stent versus stent study. Proc Inst Mech Eng H2014; 228(10): 996–1004.
10.
ShenXChenJXuY, et al. Torsional behavior of peripheral vascular stents: the role of stent design parameters. Proc Inst Mech Eng H2025; 239(2): 121–132.
11.
Ortiz-CominoRMMoralesALópez-LisbonaR, et al. Silicone stent versus fully covered metallic stent in malignant central airway stenosis. Ann Thorac Surg2021; 111: 283–289.
12.
LeyssensLEl AazmaniWBalcaenT, et al. MicroCT and contrast-enhanced microCT to study the in vivo degradation behavior and biocompatibility of candidate metallic intravascular stent materials. Acta Biomater2025; 191: 53–65.
13.
VarelaGJiménezMF.Benign tracheal stenosis should never be stented with metallic devices. Arch Bronconeumol2016; 52: 121–122.
14.
XiePFLiuYQiY, et al. Stent-in-stent technique for removal of the tracheal stent in patients with severe granulation tissue hyperplasia. Quant Imaging Med Surg2021; 11: 4676–4682.
15.
JungHSChaeGKimJH, et al. The mechanical characteristics and performance evaluation of a newly developed silicone airway stent (GINA stent). Sci Rep2021; 11: 7958.
16.
ChenSDuTZhangH, et al. Advances in studies on tracheal stent design addressing the related complications. Mater Today Bio2024; 29: 101263.
17.
BaoYDQuSQWeiW, et al. Investigation on forced vibration characteristics of Nitinol tracheal stent. Biomed Eng Online2022; 21: 85.
18.
LiYYanJZhouW, et al. In vitro degradation and biocompatibility evaluation of typical biodegradable metals (Mg/Zn/Fe) for the application of tracheobronchial stenosis. Bioact Mater2019; 4: 114–119.
19.
McGrathDJThiebesALCornelissenCG, et al. An ovine in vivo framework for tracheobronchial stent analysis. Biomech Model Mechanobiol2017; 16: 1535–1553.
20.
LiYWangYShenZ, et al. A biodegradable magnesium alloy vascular stent structure: design, optimisation and evaluation. Acta Biomater2022; 142: 402–412.
21.
SkacelPBursaJ.Poisson's ratio of arterial wall – inconsistency of constitutive models with experimental data. J Mech Behav Biomed Mater2016; 54: 316–327.
22.
HanYLuW.Optimizing the deformation behavior of stent with nonuniform Poisson's ratio distribution for curved artery. J Mech Behav Biomed Mater2018; 88: 442–452.
23.
BalanP MMertensA JBahubalendruniMVAR. Auxetic mechanical metamaterials and their futuristic developments: a state-of-art review. Mater Today Commun2023; 34: 105285.
24.
LuoCHanCZZhangXY, et al. Design, manufacturing and applications of auxetic tubular structures: a review. Thin-Walled Struct2021; 163: 107682.
25.
ZamaniAMMEtemadiEBodaghiM, et al. Conceptual design and analysis of novel hybrid auxetic stents with superior expansion. Mech Mater2023; 187: 104813.
26.
JiangDThissenHHughesTC, et al. Advances in additive manufacturing of auxetic structures for biomedical applications. Mater Today Commun2024; 40: 110045.
27.
LiuJYaoXWangZ, et al. A novel wavy non-uniform ligament chiral stent with J-shaped stress–strain behavior to mimic the native trachea. Bio-Des Manuf2021; 4: 851–866.
28.
AsadiAHedayatDGhofraniS, et al. Modification of hexachiral unit cell to enhance auxetic stent performance. Mech Adv Mater Struct2023; 30: 1470–1484.
29.
AnRGeXWangM.Vascular stents with controllable negative Poisson’s ratio based on energy homogenization method. J Phys Conf Ser2023; 2566: 012120.
30.
ChenKWanHFangX, et al. Laser additive manufacturing of anti-tetrachiral endovascular stents with negative poisson’s ratio and favorable cytocompatibility. Micromachines2022; 13: 1135.
31.
ZhangZTianRZhangX, et al. A novel butterfly-shaped auxetic structure with negative Poisson’s ratio and enhanced stiffness. J Mater Sci2021; 56: 14139–14156.
32.
AminFAliMNAnsariU, et al. Auxetic coronary stent endoprosthesis: fabrication and structural analysis. J Appl Biomater Funct Mater2015; 13(2): e127–e135.
33.
PokkallaDKPohLHQuekST.Isogeometric shape optimization of missing rib auxetics with prescribed negative Poisson’s ratio over large strains using genetic algorithm. Int J Mech Sci2021; 193: 106169.
GaoBJingHGaoM, et al. Long-segmental tracheal reconstruction in rabbits with pedicled tissue-engineered trachea based on a 3D-printed scaffold. Acta Biomater2019; 97: 177–186.
36.
PauckRGReddyBD.Computational analysis of the radial mechanical performance of PLLA coronary artery stents. Med Eng Phys2015; 37: 7–12.
37.
SafshekanFTafazzoli-ShadpourMAbdoussM, et al. Finite element simulation of human trachea: normal vs. Surgically treated and scaffold implanted cases. Int J Solids Struct2020; 190: 35–46.
38.
FarahaniMMBakhtiyariABeshkoofeS, et al. Numerical simulation of the effect of geometric parameters on silicone airway stent migration. Front Mech Eng2023; 9: 1215895.
39.
HassaniKGolmohammadiMK.Biomechanical analysis of tracheal stent during cough reflex. Proc Inst Mech Eng H2022; 236(9): 1449–1456.
40.
TianLZhanNHeH, et al. A bioinspired design approach for biomechanically matched tracheal stents. Virtual Phys Prototyp2024; 19: e2437510.
41.
RatnovskyARegevNWaldS, et al. Mechanical properties of different airway stents. Med Eng Phys2015; 37: 408–415.
42.
QinYZhangHQiuZ, et al. A two-way FSI model for pathologic respiratory processes with precisely structured and flexible upper airway. Acta Mech Solida Sin2024; 37: 910–918.
43.
GengLCRuanXLWuWW, et al. Mechanical properties of selective laser sintering (SLS) additive manufactured chiral auxetic cylindrical stent. Exp Mech2019; 59: 913–925.
44.
KapoorAJepsonNBressloffNW, et al. The road to the ideal stent: A review of stent design optimisation methods, findings, and opportunities. Mater Des2024; 237: 112556.
45.
RuanXLLiJJSongXK, et al. Mechanical design of antichiral-reentrant hybrid intravascular stent. Int J Appl Mech2018; 10: 1850105.
46.
PanCHanYLuJ.Structural design of vascular stents: a review. Micromachines2021; 12: 770.
47.
WangXDFengMSHuYC.Establishment and finite element analysis of a three-dimensional dynamic model of upper cervical spine instability. Orthop Surg2019; 11: 500–509.
48.
ZhangCXiaoSHQinQH, et al. Tunable compressive properties of a novel auxetic tubular material with low stress level. Thin-Walled Struct2021; 164: 107882.
49.
LiuJYaoXWangZ, et al. A flexible porous chiral auxetic tracheal stent with ciliated epithelium. Acta Biomater2021; 124: 153–165.
50.
LiXWangCLiuZ, et al. Study on the rationality of small diameter metallic airway stent in treatment of tracheal stenosis in injured rabbits. J Cardiothorac Surg2024; 19: 110.
51.
RobinTRobinELe BoedecK.A systematic review and meta-analysis of prevalence of complications after tracheal stenting in dogs. J Vet Intern Med2024; 38: 2034–2044.
52.
RoodenburgSAPouwelsSDSlebosDJ.Airway granulation response to lung-implantable medical devices: a concise overview. Eur Respir Rev2021; 30(161): 210066.
53.
HerthFJEberhardtR.Airway stent: what is new and what should be discarded. Curr Opin Pulm Med2016; 22(3): 252–256.
54.
HerthFJPeterSBatyF, et al. Combined airway and oesophageal stenting in malignant airway-oesophageal fistulas: a prospective study. Eur Respir J2010; 36(6): 1370–1374.
55.
GuibertNDidierAMorenoB, et al. Treatment of complex airway stenoses using patient-specific 3D-engineered stents: a proof-of-concept study. Thorax2019; 74(8): 810–813.
