Ostene, a new alkylene oxide copolymer bone hemostatic material, does not inhibit bone healing

Abstract

Objective: In this study, we investigate the effects of a soft bone hemostatic wax comprised of water-soluble alkylene oxide copolymers (Ostene; Ceremed, Inc., Los Angeles, CA) on bone healing in a rat calvaria defect model. We compared the effects with a control (no hemostatic agent) and bone wax, an insoluble and nonresorbable material commonly used for bone hemostasis.

Methods: Two bilateral 3-mm circular noncritical-sized defects were made in the calvariae of 30 rats. Alkylene oxide copolymer or bone wax was applied or no hemostatic material was used (control). After 3, 6, and 12 weeks, rats were sacrificed and the calvariae excised. Bone healing, expressed as fractional bone volume (+/- standard error of the mean), was measured by microcomputed tomography.

Results: Immediate hemostasis was achieved equally with bone wax and alkylene oxide copolymer. Bone wax-filled defects remained unchanged at all time points with negligible healing observed. At 3 weeks, no evidence of alkylene oxide copolymer was observed at the application site, with fractional bone volume significantly greater than bone wax-treated defects (0.20 +/- 0.03 versus 0.02 +/- 0.01; P = 0.0003). At 6 and 12-weeks, alkylene oxide copolymer-treated defects continued to show significantly greater healing versus bone wax (0.18 +/- 0.04 versus 0.05 +/- 0.01 and 0.31 +/- 0.04 versus 0.06 +/- 0.02, respectively). At all time points, alkylene oxide copolymer-treated and control defects showed good healing with no significant difference.

Conclusion: Alkylene oxide copolymer is an effective hemostatic agent that does not inhibit osteogenesis or bone healing.

Figures

FIGURE 1

Representative photographs of excised calvariae at 3 and 12 weeks after surgery.

FIGURE 2

Representative microcomputed tomography (microCT)-derived, 3-dimensional renderings of rat calvariae at 3, 6 and 12 weeks after surgery.

FIGURE 3

Graphs showing microCT data for control (untreated) (●), alkylene oxide copolymer-treated (■), and bone wax-treated (◀) defects at 3, 6, and 12 weeks after surgery. A, mean mineralized bone volume (BV, mm3). B, total volume (TV, mm3). C, bone volume fraction (BV/TV). Asterisks indicate a P value of less than 0.05.

FIGURE 4

Histological analysis of bone healing in calvarial defects. Representative images of 5-μm thick coronal sections from the center of the defect at 3 weeks after surgery. Toluidine blue staining demonstrates mineralized bone (blue stars), osteoblasts (red arrows), and osteoid (green arrowheads) in the control and alkylene oxide copolymer-treated defects, with mostly fibrous tissue observed at the site of the bone wax treated defects (white triangle). Both low (× 2, left) and high magnification (× 10, right) are shown.