Application of collagen sponge scaffold to muscular defects of the esophagus: an experimental study in piglets

Background/Purpose: Circular myotomy often has been used to elongate the esophagus in end-to-end anastomosis for esophageal atresia with a long gap. Defects of the muscular layer often have led to the ballooning of the esophagus during the postoperative course. Recently, successful regeneration of the neo-esophagus using collagen sponge scaffold (CSS) for self-tissue regeneration has been reported. The authors applied this CSS to the muscular defect after circular myotomy in animal experiments. Methods: Myectomy or myotomy of the cervical or thoracic esophagus was performed in 11 piglets. CSS was applied to the amuscular site, which was 20 to 30 mm in length, to examine the regeneration of the muscular layer in 8 piglets (CSS group). The amuscular site was not wrapped by CSS in 3 piglets as a control (control group). Two months after operation, the animals were killed, and their operated esophagi were examined macroscopically and microscopically. Results: All 11 piglets increased in weight normally without any sign of dysphagia or vomiting. The amuscular site onto which CSS was implanted was covered with loose connective tissue, but muscle regeneration was not found microscopically. The amuscular site, which had been wrapped by CSS, was not distended in any of the 8 piglets when inflated, and ballooning was observed in all 3 of the control group. Conclusion: The results suggested that application of CSS to the site of circular myotomy for esophageal atresia with a long gap might not induce muscle regeneration but could prevent postoperative ballooning by inducing connective tissue growth. J Pediatr Surg 37:1409-1413.