Aim: To compare the efficacy of bone graft, hydroxyapatite coralline (Biocoral®), and porous polyethylene (Medpor®) implants for cranioplasty in a rat model of cranial bone defects.
Material and methods: Two parietal bone defects were created in each of 16 male Sprague-Dawley rats. One was repaired with a bone graft using bone removed from the contralateral defect, and the other was filled with either Medpor® or Biocoral® (each n=8, with the repair on the left in four and the right in the other four). The rats were sacrificed at either 4 or 8 weeks, and implant stability, volumetric changes, and histological parameters were compared between the three materials.
Results: At 8 weeks, scores for bone formation (p=0.003), healing of the defects (p=0.008), and material resorption (p=0.010) were higher for the bone grafts than for Biocoral® and Medpor®, whereas the fibrosis scores were significantly higher for Medpor® and Biocoral® than for the bone grafts (p=0.004). The other parameters were similar between the three materials at 8 weeks, except for significantly higher inflammatory cell infiltration with Medpor® than with Biocoral® and bone grafts (p=0.005).
Conclusion: Implant stability scores were similar for the three implant materials. However, there was better bone formation and healing of the defects with bone grafts, a lower risk of resorption and greater fibrosis induction with Medpor® and Biocoral®, and less volumetric reduction with Medpor®.