Methods: Median sternotomies were performed on 20 female New Zealand White rabbits (3.75 ± 0.25 kg) using standard aseptic techniques. Sufficient bone wax (Ethicon, Inc.) or alkylene oxide copolymer (Ostene®, Ceremed, Inc.) was applied to the cut bone surface to achieve hemostasis (n = 10 per group). 2-0 monofilament suture was used to secure the sternal halves. Animals were sacrificed at 6 weeks and the sterna harvested. For histological analysis, fixed sterna were processed for undecalcified ground sectioning using Spurr embedding with Sanderson's rapid bone stain and decalcified sections stained with H&E. Mechanical strength of the sterna was measured on a MTS Synergie 100 material tester (Eden Prairie, MN) using three-point testing with a 0.2 mm/sec crosshead speed.

Results: Equivalent bone hemostasis was achieved with bone wax and alkylene oxide copolymer. After 6 weeks, histological analysis showed massive fibrotic scar tissue with no evidence of new bone formation in the bone wax group. Bone healing and new bone formation, as evidenced by regenerated bone trabeculae and marrow structure, were observed in the alkylene oxide copolymer group without any observation of fibrotic scar tissue. Mechanical testing of the sterna showed an approximate two-fold greater flexural strength (2.53 ± 0.43 versus 1.29 ± 0.37 MPa) and two-fold greater Young's modulus (0.315 ± 0.056 versus 0.146± 0.031 MPa) in the alkylene oxide copolymer group compared to the bone wax group.

Conclusion: Alkylene oxide copolymer (Ostene®) is an effective agent to achieve bone hemostasis that does not inhibit osteogenesis and bone healing. The use of alkylene oxide copolymer in place of bone wax may help reduce the occurrence of post-operative sternal dehiscence and the associated complications.