The influence of intra-graft heparin injection on the survival of composite grafts.

BACKGROUND

Intra-replant subcutaneous heparin injection has been reported to be an alternative to venous anastomoses in finger replantations. It has also been recommended for composite graft type replants. In this study, we investigated three different regimens of intra-graft heparin injection in a rabbit ear model. Our aim was to determine whether or not continuous oozing from an incision wound on a composite graft made by an intra-graft heparin injection would increase the survival of a larger composite graft.

METHODS

A 25-mm-diameter circular composite graft (including dorsal skin and auricular cartilage) was harvested from the mid-portion of a rabbit ear. This size of graft was selected as the study model due to a significantly lower percent graft survival when compared to smaller-sized grafts (17.0 +/- 5.6%, p < 0.05). Three different regimens of intra-graft heparin injection were performed in the study group and the results of percent graft survival were compared.

RESULTS

Intra-graft injection of heparin calcium 250 IU/0.1 ml qd for seven days resulted in a significantly higher percent graft survival than the other two regimens and a control group (64.0 +/- 9.7%, p < 0.05). The "flow-through" phenomenon was observed in this study.

CONCLUSIONS

Intra-graft heparin injection resulted in a higher percent graft survival than the control group for the 25-mm-diameter circular composite graft. However, the mechanism of graft survival enhancement could not be clearly explained by this study. It is recommended that the clinical application of intra-graft heparin injection should only be used when subgraft hematoma can be avoided and systemic bleeding tendency is being closely monitored.