The effect of electrical stimulation on success of bone grafts: an in vivo study

Abstract

Purpose: Bone grafting is often unpredictable and is associated with reduced success rate, extended healing times and morbidity. Methods that expedite healing and increase predictability will contribute to the overall success of reconstructive efforts. In this project, the effect of electrical stimulation on bone graft healing in rat calvaria was examined. Materials and Methods: Fifteen adult male Sprague-Dawley rats were used. A 7 mm diameter bone defect at the midline of the calvarium was grafted using freeze-dried mineralized bone. Bipolar platinum stimulating electrodes were overlaid on top of the periosteum on the center of the graft. Animals were divided randomly into two groups. The experimental group (n=8) received electrical stimulation (3 times/day for 10 days) and the control group (n=7) received no stimulation. At 6 weeks, the grafted areas together with the surrounding bone were harvested from the cranium. Tissue sections (5-7 μm) were prepared and stained using hematoxylin and eosin. Mounted slides were analyzed and for each animal, the grafted area was marked and the percent of new bone, remaining graft material and connective tissue was calculated. Data was analyzed using ANOVA. A p≤.05 was considered significant. Results: There were statistically significant differences between the experimental and control group. The electrical stimulation group had significantly more (p=0.034) bone (3.81+3.6 %) compared to the control group (0.47+0.52%). The amount of remaining graft material was also significantly higher (p=0.024)in the control group (26.11+6.54%) compared to the stimulation group (16.64+5.28%). No significant difference (p=0.15) was found between the 2 groups in the amount of connective tissue (stimulation: 79+5.47%; control: 73.2+6.82%). Conclusion: In this animal model of bone graft healing, electrical stimulation resulted in significantly more bone formation and less remaining graft material. These findings suggest that electrical stimulation expedites bone graft healing.