Bone healing after median sternotomy: a comparison of two hemostatic devices

Abstract

Background: Bone wax is traditionally used as part of surgical procedures to prevent bleeding from exposed spongy bone. It is an effective hemostatic device which creates a physical barrier. Unfortunately it interferes with subsequent bone healing and increases the risk of infection in experimental studies. Recently, a water-soluble, synthetic, hemostatic compound (Ostene®) was introduced to serve the same purpose as bone wax without hampering bone healing. This study aims to compare sternal healing after application of either bone wax or Ostene®.

Methods: Twenty-four pigs were randomized into one of three treatment groups: Ostene®, bone wax or no hemostatic treatment (control). Each animal was subjected to midline sternotomy. Either Ostene® or bone wax was applied to the spongy bone surfaces until local hemostasis was ensured. The control group received no hemostatic treatment. The wound was left open for 60 min before closing to simulate conditions alike those of cardiac surgery. All sterni were harvested 6 weeks after intervention.Bone density and the area of the bone defect were determined with peripheral quantitative CT-scanning; bone healing was displayed with plain X-ray and chronic inflammation was histologically assessed.

Results: Both CT-scanning and plain X-ray disclosed that bone healing was significantly impaired in the bone wax group (p < 0.01) compared with the other two groups, and the former group had significantly more chronic inflammation (p < 0.01) than the two latter.

Conclusion: Bone wax inhibits bone healing and induces chronic inflammation in a porcine model. Ostene® treated animals displayed bone healing characteristics and inflammatory reactions similar to those of the control group without application of a hemostatic agent.

Figure 1

Flowchart: showing how the pigs were in- and excluded.

Figure 2

CT reference lines: Sternum showing the two reference-lines used in the CT-scans. 1: Manubriosternal joint surface. 2: First growth-zone

Figure 3

CT-images: CT-images showing good central healing of the sternum in a control pig (left) and decreased central healing in a bone wax pig (right).

Figure 4

CT-results showing the bone-density measured in g/cm³: The difference between bone wax and Ostene^® and bone wax and control = p < 0.001. Means are indicated by a vertical line.

Figure 5

CT-results showing the area of the central defect in the first sternal segment: The difference between bone wax and Ostene^® and bone wax and control = p < 0.001. Means are indicated by a vertical line.

Figure 6

CT-results showing the area of the central defect in the second sternal segment. The difference between bone wax and Ostene^® and bone wax and control = p < 0.001. Means are indicated by a vertical line.

Figure 7

Histology results showing the volume fraction of granuloma to other tissue: The difference between bone wax and Ostene^® and bone wax and control = p < 0.001. Means are indicated by a vertical line.