2003 Papers - Mayfield


Initial Results of Repair of Duodenal Injuries With Elastin Biomaterial Homografts in a Porcine Abdominal Trauma Model
Mayfield MM, CPT, MC; Lane JM, CPT, MC; Cordts PA, COL, Morrison CA, MAJ, MC; Freeman JH, MD; Uyehara CFT, PhD; Cordts PR, COL, MC
Tripler Army Medical Center

Background: Battlefield injuries to the gastrointestinal (GI) tract frequently produce significant tissue loss. Initial surgical efforts focus on hemorrhage control and closing GI tract defects to minimize contamination. High velocity weapons create injuries to bowel, particularly the duodenum, which are difficult to repair by primary closure. In addition, lengthy reconstructive procedures may carry significant morbidity and mortality. The purpose of this study was to determine the efficacy of elastin biomaterial heterografts in repair of complex duodenal injuries in a porcine abdominal trauma model.

Methods: Juvenile Yucatan miniswine (Sus scrofa) were prospectively randomized into three groups: Group I - elastin patch (Oregon Medical Laser Center, Portland, OR) repair alone; Group II - elastin patch repair followed by contamination and Group III - antibiotic-impregnated (CefotetanR) elastin patch repair followed by contamination. Following a midline laparotomy under GETA, a 4 cm in length and 50% circumference bowel wall injury was created in D2. Elastin patches 4 X 1.5 cm in dimension were sutured over the defect using running 4-0 monofilament suture. Patches in Groups II and III were then exposed to 105 E. Coli and S. aureus for 30 minutes. Post-operatively, miniswine were observed for 8 weeks with endpoints of survival, sepsis, bowel obstruction, and weight gain. Prior to euthanasia, each underwent UGI series followed by duodenal harvest to determine patch integrity, patch infection, and duodenal stenosis. Post-mortem analysis consisted of paraduodenal aerobic and anaerobic cultures and light microscopy of duodenal sections with H&E and Verhoeff/Van Gieson's stains (elastin).

Results: Twenty-four surgeries were performed with nine models harvested and fifteen still undergoing study. Patches tended to dehydrate rapidly in air. Initial patch hydration was 43.6 + 1.4% (n=10); 30 minutes after package opening weight loss of 12.7 + 0.7% had occurred. Eight miniswine thrived with average 40% weight gain from baseline and no clinical evidence of sepsis or bowel obstruction. One miniswine was sacrificed on POD #2 due to sepsis from a duodenal leak. UGI studies (n=3) revealed no duodenal stenosis. Duodenal circumference measurements showed < 3% luminal stenosis at the patch site. No intrabdominal infections occurred. Three miniswine developed a wound infection with S. aureus. H&E stains showed focal disruption of the muscular layer with fibrosis, inflammation and foreign body giant cell reactions. Microscopic fragments of elastin were identified by elastin stains in each case.

Conclusion: Elastin patches functioned effectively in this challenging anatomic location, even in the face of contamination. The benefit of antibiotic incorporation into the patch is undefined. While further testing is warranted, early results of this animal study suggest that use of such homograft implants may be a viable option for management of complex bowel trauma in the future.