Experimental reconstruction of cervical esophageal defect with artificial esophagus made of polyurethane in a dog model

摘要

The defect of esophagus after surgical excision in patients is usually replaced by autologous stomach, jejunum, or colon. The operation brings severe trauma and complications. Using artificial esophagus to replace the defect in situ can reduce the operative trauma, simplify the operative procedures, and decrease the influence to digestive function. A variety of experiments have been designed for developing a practical artificial esophagus. Nevertheless, a safe and reliable artificial esophagus is not yet available. The objective is to evaluate the possibility of the artificial esophagus made of non-degradable polyurethane materials being used in reconstruction of the segmental defect of cervical esophagus in beagles, observe the regeneration of esophageal tissue, and gather experience for future study. The cervical esophageal defects in 13 beagles were designed to 2-cm long and were constructed by the artificial esophagus made of non-degradable polyurethane materials. Nutrition supports were given after the operation. The operative mortality, anastomotic leakage, migration of artificial esophagus, and dysphagia were followed up. The regeneration of the esophageal tissues was evaluated by histopathology and immunohistochemical labeled streptavidin-biotin method. The surgical procedures were successfully completed in all beagles, and 12-month follow-ups were done. Only one beagle died of severe infection, and all others survived until being killed. The anastomotic leakage occurred in nine beagles, most of them (8/9) were cured after supportive therapy. The migration of artificial esophagus occurred in all 12 surviving beagles, and one artificial esophagus stayed in situ after migration. All 12 surviving beagles showed dysphagia with taking only fluid or soft food. No beagle died of malnutrition. The neo-esophagus was composed of granulation tissue, and the inner surface was covered by epithelium in 2-3 months completely. But the inner surface of neo-esophagus with artificial esophagus staying in situ after migration was not covered by epithelium, and the granulation tissue was infiltrated by a great deal of inflammatory cells. Antibodies against cytokeratin were positively expressed in epithelium of neoesophagus. Up to 12 months after operation, antibodies against smooth muscle actin and desmin were both negatively expressed in neo-esophagus. The artificial esophagus made of non-degradable polyurethane reconstructing cervical esophageal defect is practicable. Although there are some problems, including anastomotic leakage, migration, and dysphagia, they are not lethal following good supportive therapy. The esophageal epithelium can regenerate with the supporting role of artificial esophagus. In the future, deformable artificial esophagus should be improved, and a much longer follow-up will be performed to evaluate whether the esophageal gland and skeletal muscle can regenerate.