Donneys Alexis, Tchanque-Fossuo Catherine N, Farberg Aaron S, Deshpande Sagar S, Buchman Steven R
Craniofacial Research Laboratory, Plastic Surgery Section, University of Michigan Ann Arbor, Michigan 28109-4217, USA.
J Craniofac Surg. 2012 Jan;23(1):328-32. doi: 10.1097/SCS.0b013e318241db26.
Tissue analysis of bone regenerate has suggested an intense vascular response after mandibular distraction osteogenesis (DO). Quantifying and three-dimensionally imaging this vascular response could be of immense clinical import in efforts to advance the utility of bone regeneration and repair. Conventional quantification of vascular responses has heretofore focused on inexact, cumbersome measurements of blood flow and histologic vessel counting. Using micro-computed tomography after vessel perfusion, we posit that quantitative vascular metrics will be significantly higher in mandibular DO compared with those observed in fracture repair (FxR) after bony union.
Sprague-Dawley rats underwent mandibular osteotomy and external fixator placement. A DO group (n=9) underwent a 5.1-mm distraction, whereas a FxR group (n=12) had a 2.1-mm fixed gap set. Forty days after surgery, Microfil was perfused into the vasculature, and imaging ensued. Vascular radiomorphometrics were calculated for the regions of interest. Independent-samples t-test was performed for comparison, with statistical significance set at P≤0.05.
Stereological analysis demonstrated statistically significant increases in the distracted vasculature compared with fracture repair: vessel volume fraction (5.4% versus 2.8%, P=0.030) and vessel number (0.86 versus 0.50 mm, P=0.014).
We report robust and quantifiable increases in vascular density in DO compared with FxR. Our findings support a significant distinction between the regenerative processes of mandibular DO from the reparative mechanisms controlling fracture healing. A better understanding of the differences between the 2 types of bone formation may enable clinicians to selectively optimize therapeutic outcomes in the future.
骨再生组织分析表明，下颌骨牵张成骨术（DO）后会出现强烈的血管反应。对这种血管反应进行定量和三维成像，对于提高骨再生和修复的效用具有巨大的临床意义。以往对血管反应的常规定量方法主要集中在对血流进行不精确、繁琐的测量以及组织学血管计数上。我们推测，在血管灌注后使用微型计算机断层扫描，与骨折愈合（FxR）后的情况相比，下颌骨DO中的定量血管指标会显著更高。
对Sprague-Dawley大鼠进行下颌骨截骨术并放置外固定器。DO组（n = 9）进行5.1毫米的牵张，而FxR组（n = 12）设置2.1毫米的固定间隙。术后40天，将Microfil灌注到脉管系统中，然后进行成像。计算感兴趣区域的血管放射形态计量学指标。进行独立样本t检验进行比较，设定统计学显著性为P≤0.05。
体视学分析表明，与骨折修复相比，牵张后的脉管系统有统计学显著增加：血管体积分数（5.4%对2.8%，P = 0.030）和血管数量（0.86对0.50毫米，P = 0.014）。
我们报告，与FxR相比，DO中的血管密度有显著且可量化的增加。我们的研究结果支持下颌骨DO的再生过程与控制骨折愈合的修复机制之间存在显著差异。更好地理解这两种骨形成类型之间的差异，可能使临床医生在未来能够有选择地优化治疗效果。
