(Historical Development) Endotracheal stent is a certain tension and elastic support (airway stent) placed into the airway to dilate the narrowed airway or to seal the defective airway fistula. Xiaoping Wang, Department of Respiratory Medicine, Shandong Chest Hospital The use of airway stents can be traced back to the late 19th century, when Dr. Bond surgically placed T-tubes to treat tracheal stenosis. Since then, with the continuous development of material science and the popularity of bronchoscopy, airway stents have been gradually and widely used in clinical practice. For example, in 1992, NashefSA successfully used metal stents for the treatment of benign airway stenosis, and in 1994, KishiK et al. used a polyester fabric-coated Z-stent for the treatment of malignant airway stenosis. At present, there are two main types of metal stents commonly used in China, one is bare metal stent and the other is laminated metal stent, the former is widely used for malignant airway stenosis and the latter can be used for the treatment of airway fistula in addition to malignant airway stenosis. In addition, silicone stents were successfully introduced in China with 2014, which have great advantages in the treatment of benign airway. Silicone stents: laminated metal stents: bare metal stents: (Indications Title I) Endotracheal stents are endotracheal supports (airway stents) placed into the airway with certain tension and elasticity to dilate a narrowed airway or seal a defective airway fistula. By definition, the indications for endotracheal stenting include lumen reconstruction for central airway organic stenosis and closure of airway bronchial fistulas or fissures. Airway stenosis is classified as malignant or benign in terms of the nature of the lesion, and in terms of the anatomy of the stenosis, there are four types: intraductal, mural, external pressure, and softening. Endotracheal: Wall: External pressure: Softening: (Types of airway stents Part I) Endotracheal stents are supports (airway stents) that are placed into the airway with some tension and elasticity to dilate the narrowed airway or to seal the defective airway fistula. Currently, there are many different types of stents available in clinical practice, and they have different biomechanical properties depending on the material used to make them. Generally speaking, we classify airway stents into three categories: 1. tubular stents (non-metallic stents), including Montgomery T-tubes, Dumon, Polyflex, Noppen and Hood stents. 2. Metal stents (coated or uncoated), including Gianturco, Palmaz, Ultraflex stents, etc. 3. Hybrid stents (silicone stents with metal ring reinforcement), including Orlowski, Dynamic stents, etc. The tubular stent is cheaper, easier to remove, less deformable and less likely to stimulate granulation tissue proliferation. Its complications include displacement, mucus plug formation, thicker stent thickness that does not deform with stenosis, impedes airway mucus cilia removal, and requires rigid bronchoscopy for implantation. Tubular stents and hybrid stents: (a) Rusch stent (b) Dumon tracheal stent (c) Dumon bronchial stent (d) Montgomery T-tube (e) Hood bronchial stent (f) Orlowski stent (g) Hood custom tracheobronchial stent The above is translated from: “Interventional Bronchoscopy” (Types of airway stents Part II) Types of metal stents: According to the material of manufacture, metal stents are divided into nickel-titanium memory alloy stents and stainless steel stents. According to the presence or absence of perithelium, metal stents are divided into perithelial stents and non-perithelial stents (bare stents). According to the characteristics of lesions, they can be made into various forms such as straight tube type and bifurcation type. In terms of advantages, metal stents, for one, allow radiographic identification of their location due to their radiopaque properties; in addition, they are more malleable and can be placed in twisted narrow airways, and metal bare stents can preserve the function of cilia to remove mucus. Complication aspects include stimulation of granulation tissue proliferation, infection, and difficulty in stent removal and movement after 6-8 weeks of stent implantation. The figure above shows the different types of metal stents, from left to right, Palmaz stent, Strecker stent, uncoated Ultraflex stent, coated Ultraflex stent, uncoated Wall stent, and coated Wall stent. (To be continued)