Preidler K W, Lemperle S M, Holmes R E, Calhoun C J, Shors E C, Brossmann J, Sartoris D J
Department of Radiology, Veterans Affairs Medical Center.
Invest Radiol. 1996 Nov;31(11):716-23. doi: 10.1097/00004424-199611000-00006.
The authors evaluate whether dual-energy x-ray absorptiometry (DXA) is a reliable method to determine the density of natural coralline hydroxyapatite (HA) blocks used as bone graft substitutes.
To evaluate the basic density of HA blocks from the same coral heads with and without titanium meshes, densitometry of 12 HA-500 blocks (genus Goniopora) and 12 HA-200 blocks (genus Porites) was performed. In addition, density measurements of 30 HA blocks (HA-500, n = 15; HA-200, n = 15) from different coral heads were obtained to assess if the originating coral head influences the basic density of blocks within one coral genera. To assess standard deviation serial measurements on eight coralline HA blocks, four with titanium meshes and four without were performed. In the ex vivo study, densitometry of 12 HA blocks (HA-500, n = 4; HA-200, n = 8) used as bone graft substitutes in the mandibles and craniums of adult mongrel dogs was performed. Densities were measured after bone ingrowth for 2 and 4 months, respectively. All measurements were obtained with a Lunar DPX with scan mode "slow 750" in the spine program with the regions-of-interests selected manually. Bone ingrowth was assessed by computer-assisted histomorphometry, which was considered the gold standard. Statistical analysis was performed to correlate the densities of plain HA blocks with and without meshes to the specific weights of the blocks.
Significant positive correlation was found between the density of each HA block (both coral species) with and without meshes and the calculated specific weights. Densitometry values showed no significant differences depending on the originating coral heads. Standard deviation ranged between +/- 3.8% and +/- 4.1% (HA-500) and between +/- 3.0% and +/- 3.8% (HA-200). Hydroxyapatite-500 blocks showed marked increased densities between 15% and 34% after 4 months in three specimens in which bone ingrowth between 16.9% and 21.1% was revealed by histomorphometry; no increase of density was observed in one specimen, which presented only minimal bone ingrowth and signs of infection. Despite bone invasion between 12% and 25.8%, no increased densities were observed for HA-200 implants.
Dual-energy x-ray absorptiometry is an accurate and reproducible modality to assess the densities of plain coralline HA blocks and to monitor bone ingrowth into coralline HA-500 but not into HA-200 block implants.
作者评估双能X线吸收测定法（DXA）是否是确定用作骨移植替代物的天然珊瑚羟基磷灰石（HA）块密度的可靠方法。
为评估有无钛网情况下来自同一珊瑚头的HA块的基本密度，对12块HA-500块（角孔珊瑚属）和12块HA-200块（孔珊瑚属）进行了密度测定。此外，获取了来自不同珊瑚头的30块HA块（HA-500，n = 15；HA-200，n = 15）的密度测量值，以评估起源珊瑚头是否会影响一个珊瑚属内块体的基本密度。为评估标准偏差，对8块珊瑚HA块进行了系列测量，其中4块有钛网，4块没有。在体外研究中，对成年杂种犬下颌骨和颅骨中用作骨移植替代物的12块HA块（HA-500，n = 4；HA-200，n = 8）进行了密度测定。分别在骨长入2个月和4个月后测量密度。所有测量均使用Lunar DPX，在脊柱程序中采用“慢750”扫描模式，手动选择感兴趣区域。通过计算机辅助组织形态计量学评估骨长入情况，这被视为金标准。进行统计分析以将有无网的普通HA块的密度与块体的比重相关联。
发现有无网的每种HA块（两种珊瑚种类）的密度与计算出的比重之间存在显著正相关。密度测定值显示，根据起源珊瑚头的不同没有显著差异。标准偏差在±3.8%至±4.1%（HA-500）和±3.0%至±3.8%（HA-200）之间。在3个标本中，HA-500块在4个月后密度显著增加了15%至34%，组织形态计量学显示其中骨长入在16.9%至21.1%之间；在1个标本中未观察到密度增加，该标本仅呈现极少的骨长入和感染迹象。尽管HA-200植入物的骨侵入在12%至25.8%之间，但未观察到密度增加。
双能X线吸收测定法是评估普通珊瑚HA块密度以及监测骨长入珊瑚HA-500但不是HA-200块植入物的准确且可重复的方法。
