Polytetrafluoroethylene patch grafting for closure of stomach defects in the rat

Extensive regeneration of the stomach using bioabsorbable polymer sheets

BACKGROUND

The growing prevalence of endoscopic surgery in recent years has led to the minimization of postoperative scarring. However, this procedure does not allow for the regeneration of the resected digestive tract, which compromises the postoperative maintenance of digestive function. In this preliminary study, we developed an artificial gastric wall (AGW) using bioabsorbable polymer (BAP), and evaluated the ability of this BAP patch to repair and regenerate a widely defective gastric wall in an animal model.

METHODS

Pigs were laparotomized under general anesthesia. An 8 × 8-cm, round portion of the anterior gastric wall was excised and replaced by an AGW. The AGW was composed of a copolymer comprising 50% lactic acid and 50% caprolactone. The animals were relaparotomized 4, 8, or 12 weeks after implantation, after which they underwent resection of the entire stomach for gross and histologic evaluation of the graft sites.

RESULTS

All recipient pigs survived until killing. By 4-8 weeks, the graft site revealed progressively fewer mucosal defect after each day. Moreover, the grafted area was indistinguishable from the native stomach 12 weeks after AGW implantation. The structures of the regenerated mucous membrane and muscle layers were identical to those of the native stomach. Furthermore, proton pumps were found in the regenerated tissue.

CONCLUSION

The BAP sheets helped to restore extensive gastric defects without causing any deformation. The use of BAP sheets may become a new therapeutic method that prevents alterations of gastric volume after extensive gastrectomy for stomach cancer and other diseases.

Repair of gastric defects with an equine pericardial patch

PURPOSES

The objective of this study was to test the efficacy of an equine pericardial patch for repairing full-thickness defects of the stomach wall.

METHODS

Circular defects, 1.5 cm in diameter, were created on the anterior wall of the stomach of 12 female New Zealand rabbits. The defects were repaired by an equine pericardial patch. After euthanasia at different time intervals (3 days to 8 weeks) a macroscopic evaluation of the abdominal cavity (including adhesion scoring), mechanical testing and a histological examination of the stomach were performed.

RESULTS

The animals survived the surgical procedure and underwent an uneventful recovery until euthanasia. None of the patches failed. Adhesions were observed in all animals and were significant in 3/12 animals. Bursting pressure testing indicated that the repair was durable and that adequate strength to prevent patch failure was achieved by the second week. A histological examination showed gradual narrowing of the perforation site by mucosal and limited muscular regeneration.

CONCLUSIONS

The equine pericardial patch was successfully used to repair a gastric defect in our experimental model, and it seems that it could have potential as a material suitable for further research concerning the repair of upper gastrointestinal defects.

Salvage repair of anastomotic dehiscence following colon surgery using an expanded polytetrafluoroethylene graft

Anastomotic dehiscence is a serious complication of colorectal surgery that causes death in up to 40% of cases in which it occurs. Edema and inflammation due to abdominal sepsis can prevent the use of standard management (i.e., colostomy, ileostomy or Hartmann's procedure), in which case alternative salvage repair methods are required. The present report describes the treatment of a 73-year-old female patient at high risk of mortality because of intraabdominal sepsis due to suture dehiscence following a right hemicolectomy and ileo-transversostomy. Several surgical repair procedures were tried, but all failed. We then used an expanded polytetrafluoroethylene (ePTFE) graft in salvage repair, and this approach proved successful. This is the first report to describe clinical, macroscopic and histopathological findings, following use of an ePTFE graft in colorectal repair in humans.

Bioprosthetic repair of complex duodenal injury in a porcine model

BACKGROUND

Complex duodenal injury remains a challenging problem for the trauma surgeon. Although primary repair of small injuries is often possible, extensive damage requires complex enteric reconstruction and drainage procedures. We sought to determine the efficacy of a bioprosthetic repair for large duodenal wounds in a porcine model.

METHODS

A 60% circumferential wall defect in the second portion of the duodenum was created in eight female Yorkshire swine (38 kg +/- 5 kg). After 30 minutes of peritoneal soilage, a bioprosthetic repair using 1.5 mm porcine acellular dermal matrix was performed. Animals were recovered and resumed a normal diet on day 3. Repeat abdominal exploration and anastomotic bursting pressure strength was performed at 1-, 2-, 3-, and 6-week intervals. Pathologic analysis of all specimens was performed.

RESULTS

All animals tolerated a normal diet postoperatively, with progressive weight gain and normal bowel function. On re-exploration, no animal had evidence of duodenal stenosis, proximal dilation, or abscess formation. Pathologic analysis demonstrated progressive in-growth of native bowel tissue, with almost complete incorporation at 6 weeks. Mean bursting pressure (202 mm Hg +/- 60 mm Hg) occurred at native bowel, not patch repair site, in three of eight animals.

CONCLUSION

Bioprosthetic repair of enteric wall defects, even in proximity to upper intestinal secretions, allows successful recovery of bowel function and injury repair without extensive anatomic reconstruction. This technique may provide a more conservative approach to the treatment of complex duodenal injuries after trauma.

Evaluation of porcine-derived small intestine submucosa as a biodegradable graft for gastrointestinal healing

High-risk anastomoses in the gut may benefit from the application of a synthetic reinforcement to prevent an enteric leak. Recently a porcine-derived small intestine submucosa (SIS) was tested as a bioscaffold in a number of organ systems. The aim of this study was to evaluate the effectiveness of SIS in stimulating healing in the stomach. Twelve rats underwent surgical removal of a full-thickness gastric defect (1 cm) and subsequent repair with a double-layer patch of porcine-derived SIS. The graft was secured with interrupted sutures placed within 1 mm of the edge of the graft. After 21 days, the animals were killed and their stomachs harvested for histologic examination. Cross sections were processed for paraffin embedding and 4-micron sections were stained with hematoxylin and eosin. All animals survived, gained weight, and demonstrated no signs of peritonitis over the 3-week postoperative period. On postmortem examination, the defect was completely closed in all animals by granulation tissue and early fibrosis. Although most of the luminal surface of the grafted areas remained ulcerated, early regeneration of normal gastric mucosa was seen at the periphery of the defect. SIS may act as an effective scaffolding agent for intestinal mucosa and may offer protection in high-risk anastomoses.

Repair of full-thickness defects in alimentary tract wall with patches of expanded polytetrafluoroethylene

OBJECTIVES

To test the efficacy of patches of expanded polytetrafluoroethylene (ePTFE) for the repair of full-thickness defects in alimentary tract wall.

SUMMARY BACKGROUND DATA

A recent report of successful replacement of duodenal wall with patches of ePTFE was met with skepticism and clearly warranted confirmation as well as evaluation in repair of other segments of the abdominal intestinal tract.

METHODS

Defects of 4 cm2 were created in various segments of canine abdominal alimentary tract (stomach, duodenum, small bowel, and colon) as well as in bladder dome. For the duodenum in 13 dogs, three different ePTFE fabrications were used: CVX (cardiovascular), PDX (preclude dura membrane), and DLM (dual mesh plus). In repair of the other areas in six dogs, the PDX patch was used. When the animals were killed, both gross inspection of the parietes and tissue for histologic study became the basis for evaluation. Peritoneal and intraluminal cultures of the specific study viscera were also taken.

RESULTS

There were no patch failures. Only six significant adhesions were noted in 3 of the 19 dogs. Serosal surface healing was complete without exception by 1 week in all animals. Patches of CVX and PDX had heaping mucosa at the margin of well-sealed patch edges in the study involving duodenum. However, the DLM patch had an undergrowth of mucosa with partial patch separation by 1 week, beginning patch extrusion into gut lumen at 3 weeks, and total separation of patch with complete mucosal repair at 6 weeks. The fate of the PDX patches at 6 weeks in stomach, small bowel, colon, and bladder was identical to what had been observed for the PDX patch in the duodenum. All peritoneal and bladder cultures had no growth, whereas the contents of the alimentary tract grew expected flora.

CONCLUSIONS

These observations suggest that ePTFE may well be an acceptable membrane for at least temporary replacement of full-thickness hollow viscus defects, even in the face of heavy bacterial contamination, and that certain structural configurations of ePTFE may provide a base for increasing absorptive mucosal surface area.

Comparison of different surgical repairs in the treatment of experimental duodenal injuries

BACKGROUND

In this experimental study, we aimed to investigate the results of different surgical repair methods for delayed reconstruction of severe experimental duodenal defects.

METHODS

A large duodenal defect with irregular and tagged margins covering about 50% of the circumference was created in the second part of duodenum of male Wistar rats. The effectiveness of primary repair, jejunal serosal patch, Roux-en-Y duodenojejunostomy, or expanded polytetrafluoroethylene patch repair techniques were investigated on the basis of survival and histologic assessment.

RESULTS

No significant survival benefit was observed between jejunal serosal patch, Roux-en-Y duodenojejunostomy, or expanded polytetrafluoroethylene patch repair techniques. But these repair modalities were associated with better survival rates than no-treatment or primary repair techniques. Complete coverage of the expanded polytetrafluoroethylene grafts by neomucosa consisting of columnar epithelium with villus formation was observed in surviving rats about 16 weeks after surgery.

CONCLUSIONS

Expanded polytetrafluoroethylene patch can be used in the repair of experimental large duodenal defects, which can not be repaired primarily.