Department of Orthopaedic Surgery, William Beaumont Hospital, Royal Oak, MI 48073, USA.
Spine J. 2011 Jun;11(6):560-7. doi: 10.1016/j.spinee.2009.12.006. Epub 2010 Jan 25.
Use of recombinant human bone morphogenetic protein-2 (rhBMP-2) has been shown to enhance spinal fusion rates. Case reports of soft-tissue swelling, ectopic bone formation, and osteolysis have recently surfaced. It is hypothesized that incorporation of rhBMP-2 within a calcium phosphate (CaP) coating may help to localize delivery and mitigate these complications.
To compare the characteristics of posterolateral fusion between rabbits receiving rhBMP-2 delivered via physical adsorption to a collagen sponge or rhBMP-2 incorporated within the physical structure of a CaP coating on a collagen sponge.
STUDY DESIGN/SETTING: New Zealand white rabbit model of posterolateral lumbar fusion at L5-L6.
Eighteen (18) New Zealand white rabbits underwent posterolateral spinal fusion at L5-L6. Rabbits received bilateral collagen sponges that were either coated with CaP (n=3), coated with CaP and dipped in rhBMP-2 (n=3), coated with a hybrid CaP-rhBMP-2 film (n=6), or coated with a hybrid CaP-rhBMP-2 film and dipped in rhBMP-2 (n=6). Animals were followed weekly with radiographs and were sacrificed at 6 weeks. Fusion masses were further characterized by manual palpation, computed tomography, and histology.
Radiographic evaluation showed that animals in Group 3 (incorporated BMP) fused at 4 weeks, whereas animals in Group 2 (adsorbed BMP) and Group 4 (incorporated and adsorbed BMP) fused by 6 weeks. Animals that received rhBMP-2 physically adsorbed to the collagen sponge showed extension of the fusion mass beyond the L5-L6 level in 56% of cases and bone resorption in 78%. Histology of fusion masses showed mature bone formation in animals belonging to Groups 2, 3, and 4 and extensive osteoclast recruitment in animals belonging to Groups 2 and 4.
Delivery of rhBMP-2 via incorporation within CaP coatings results in increased rates of radiographic fusion. The burst release profile of rhBMP-2 adsorbed to surfaces, although effective in achieving fusion, may result in increased osteoclast recruitment.
已证实，使用重组人骨形态发生蛋白-2（rhBMP-2）可提高脊柱融合率。最近有软组织肿胀、异位骨形成和骨溶解的病例报告。假设将 rhBMP-2 掺入到磷酸钙（CaP）涂层中可以帮助定位递送并减轻这些并发症。
比较通过物理吸附到胶原海绵上的 rhBMP-2 或掺入胶原海绵物理结构中的 rhBMP-2 来递送 rhBMP-2 的兔模型在后外侧腰椎融合中的特征。
研究设计/地点：新西兰白兔 L5-L6 后外侧腰椎融合模型。
18 只新西兰白兔接受 L5-L6 双侧后外侧脊柱融合术。兔子接受了涂有 CaP（n=3）、涂有 CaP 并浸有 rhBMP-2（n=3）、涂有混合 CaP-rhBMP-2 膜（n=6）或涂有混合 CaP-rhBMP-2 膜并浸有 rhBMP-2（n=6）的胶原海绵。每周通过 X 线检查进行随访，并在 6 周时处死。融合块通过手动触诊、计算机断层扫描和组织学进一步进行特征描述。
放射学评估显示，第 3 组（掺入 BMP）的动物在 4 周时融合，而第 2 组（吸附 BMP）和第 4 组（掺入和吸附 BMP）的动物在 6 周时融合。接受物理吸附到胶原海绵上的 rhBMP-2 的动物有 56%的病例融合块延伸超出 L5-L6 水平，有 78%的病例发生骨吸收。属于第 2、3 和 4 组的融合块的组织学显示成熟骨形成，而属于第 2 和 4 组的动物有大量破骨细胞募集。
通过掺入 CaP 涂层递送 rhBMP-2 可提高放射学融合率。尽管吸附到表面的 rhBMP-2 呈爆发式释放，但在实现融合方面有效，可能导致破骨细胞募集增加。
