Apatite‐Coated Collagen Sponge for the Delivery of Bone Morphogenetic Protein‐2 in Rabbit Posterolateral Lumbar Fusion

Bone morphogenetic proteins (BMPs) need an effective delivery system for efficient bone regeneration. In this study, we evaluated the efficiency of an apatite-coated collagen sponge for the long-term delivery of BMP-2 in a rabbit model of lumbar posterolateral fusion. A total of 15 rabbits, divided into three groups, underwent posterolateral lumbar fusion. The first group (control group) received uncoated collagen sponges without BMP-2. The second group (uncoated group) received uncoated collagen sponges with BMP-2 (40 μg each side). The third group (apatite-coated group) received apatite-coated collagen sponges with the same level of BMPs (40 μg each side). All rabbits were euthanized 6 weeks after operation, and the fusion status was assessed by radiographic study, micro-CT, manual palpation, biomechanical study, and histological examination. Fusion rates as determined by radiographic …