Esophageal Stenture

Esophageal benign stricture is the pathological stricture caused by any disease in esophageal antrum. In addition, the external pressure of the mucosal ring and the mediastinal tissue can also cause esophageal stricture. Benign stricture of the esophagus (BSE) can severely reduce quality of life and cause major complications such as aspiration, weight loss and malnutrition [1]. Esophageal stent implantation has been widely used in clinical practice, and this surgical method effectively alleviates patients with dysphagia and has excellent treatment results. Clinical research [2-4] confirmed that esophageal stent implantation for esophageal benign stricture can achieve satisfactory results.
Metal and polymer stents are now the most widely used
Currently, polymer esophageal stent mainly consists of polymer membrane-coated metal stent, which takes advantage of the mechanical performance of metal stents, and covers a layer of polymer coating on the outside which improves the implantation and removal procedure. Poly(e-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC) are two aliphatic polyesters. They are both biodegradable and biocompatible but have different biodegradation rates and different biomedical applications. PCL is a semi-crystalline polymer and has been widely used in tissue engineering scaffolding, that being due to the properties including: nonimmunogenicity, slow biodegradability and good drug permeability[16]. PTMC is an amorphous biomaterial which holds elastic properties at ambient temperature. It exhibits good mechanical resistance and high chemical and thermal stability. In vivo biocompatibility and toxicity assays revealed that PTMC blend had no influence on heart, liver, and kidney tissues [17]. The synthetic copolymer of the two, P(CL-TMC), has been investigated as biopolymer to be used for surgery and nerve guide repairs because of its high biocompatibility and the advantage of controllable both the mechanical property and the degradation rates[18,19]. Hitherto, the more
(Qingdao, China). was used to coat the magnesium stent via the dipping and spinning method: (a) Precision aluminum molds of the stent were used to fabricate the magnesium wires framework. (b) Equal portions of the two parts of the PCL and PTMC were thoroughly blended together（blend ratios of PCL and PTMC 5:5, w/w) were dissolved in a mixture of N-octane as a solvent prior to use. (c) The mixed (PCL-PTMC) copolymer was dipped on the magnesium stent mould repeated five times and cured for 6 h at 80°C for drying. The moulds were cooled for 3 h in ambient conditions; the stent prototypes were stripped from the moulds. Thus this process ensure the fabric shape and function will remain stable after withdraw from metal mandril. The stent body was not radio-opaque, so a mark was placed at its distal end to facilitate accurate positioning under