Repairing partial esophageal defects with pulmonary tissue flap in dogs:A feasibility study

Zhao JG, Zhang SN, Shi WJ, Han Y, Deng CF 1Department of Thoracic Surgery, Second Affiliated Hospital, China Medical University, Shenyang 110004, Liaoning Province, China; 2Department of General Surgery, General Hospital of Tonghua Coal Mining Bureau, Baishan 134300, Jilin Province, China  

AIM: To analyze the feasibility of repairing the partial esophageal defect with pulmonary tissue flap of dogs. METHODS: The experiment was conducted at the Animal Laboratory, Second Affiliated Hospital, China Medical University from January 2003 to November 2004. Twenty adult mongrel dogs were used for the study, which were divided into two groups: stent group and non-stent group with 10 in each group. The partial full-thickness esophageal wall defect, which was 4 cm long and 1/2-2/3 circled esophagus was repaired by pulmonary tissue flap at the fifth rib of right thorax in the 20 dogs. The lobar bronchus of lung was ligated, so the pulmonary tissue flap was made. In the two groups, pulmonary tissue flap was covered, sutured and fixed at esophageal wall defect. In the stent group, esophagus replacement was done by pulmonary tissue flap with the self-expanded alloy stent inside in dogs (the diameter of lumina of 2.0 cm and length of 6.0 cm). Antibiotics and nutritious therapy were used after operation. The dogs were put to death at weeks 2, 4, 6, 8, 10 and 12 routinely and histological examination was used for the study. RESULTS: Totally 7 dogs were survival in the non-stent group, of which 1 dog was survival for more than 24 months, and 6 dogs were survival in stent group. ①General condition of experimental dogs after operation: The survival dogs could eat normally after operation, but vomited and ate the vomited in the early phase, especially in stent group. ②Observational result of histology: Two weeks after operation, the esophageal defect was covered with collagen layer and inflammation exudation. A little epithelization was observered at free edge of the anastomosis, which was 1-2 layers of stratified squamous epithelium cells in both groups. In stent team, stents were fixed well and there were many neutrophilic granulocytes at the spots where stents oppressed under light microscope. At weeks 4-6 after operation, the internal surface of the defect was covered with 3-5 layers of stratified squamous epithelium cells in both groups. In stent team, stents entered into the mucosa. At weeks 8-10, the luminal surface of the defect was covered with 6-8 layers of stratified squamous epithelium cells in both groups. In stent team, scar hyperplasia was found at the edge of stents that were wrapped entirely, interruption and a little epithelization were observered at the spots with serious inflammation that was 1-2 layers of stratified squamous epithelium cells. CONCLUSION: It is feasible to repair the partial esophageal defect with the pulmonary tissue flap in dogs, but the stent in the stent group has great stimulation on repaired esophagus, with severe inflammatory reaction and severe scar. Therefore, how to choose suitable stent is a major problem for replacing segmental esophageal defect in the future.

【Fund】： 卫生部科技专项立项资助项目(WKZ-2000-1-17)~~
【CateGory Index】： R655

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