Bioabsorbable Gelatin Sheets Latticed With Polyglycolic Acid Can Eliminate Pericardial Adhesion

Background: As an extension of our previous studies on bioabsorbable pericardial substitutes, we have created a new form of gelatin sheets latticed with bioabsorbable polyglycolic acid (PGA). This study was undertaken to evaluate the biomechanical property of the sheet and the preventive effect on pericardial adhesions after pericardial replacement in a canine model before its clinical applications. Methods: The mechanical property was assessed by measuring tension of suture pull-out at first break test. Fifteen dogs underwent partial pericardial replacement with the bioabsorbable sheets through a left thoracotomy. Macroscopic assessment for severity of adhesions and microscopic evaluation for histologic changes were made at 2, 4, 12, and 24 weeks postoperatively. Results: The latticed sheets exhibited tenfold higher tension of disruption at the suturing margin compared to our previously developed gelatin sheets (619 ± 141 versus 62 ± 7 gf, p < 0.001), and demonstrated equivalent strength to that of clinically available expanded polytetrafluoroethylene membrane. During rethoracotomy, adhesions between the epicardium and the pericardial substitutes were moderate at the 4-week interval and resolved completely after 12 weeks postoperatively. Inflammatory reaction scores graded into 4 scales on histologic assessment were 2 ± 0.0, 1.6 ± 0.6, and 0.3 ± 0.5 at 4, 12, and 24 weeks, respectively. Inflammatory reaction significantly decreased from the 4-week interval to the 24-week interval after the pericardial replacement (p < 0.05). Conclusions: The bioabsorbable gelatin sheets latticed with PGA gained improved mechanical properties compared with the previously reported gelatin sheets without impairing its bioabsorbability. The bioabsorbable sheet could eliminate pericardial adhesions after being replaced with regenerated tissue.