FTIR MICROSPECTROSCOPIC ANALYSIS OF HUMAN ILIAC CREST BIOPSIES FROM UNTREATED OSTEOPOROTIC BONE

Historically, osteoporosis has been defined as a disease in which ther e is ''too little bone, but what there is, is normal.'' As a result of research design and sample selection limitations, published data cont radict and confirm the historical definition. Because of these limitat ions, it has been hard to assess the contribution of mineral quality t o mechanical properties, and to select therapeutic protocols that opti mize bone mineral properties. The coupling of an optical microscope to an infrared spectrometer enables the acquisition of spectral data at known sites in a histologic section of mineralized tissue without loss of topography and/or orientation. The use of second-derivative spectr oscopy coupled with curve-fitting techniques allows the qualitative an d quantitative assessment of mineral quality (crystallite size and per fection, mineral:matrix ratio) at well-defined morphologic locations. We have previously applied these techniques to the study of normal hum an osteonal, cortical, and trabecular bone. The results indicated that the newly deposited bone mineral is less ''crystalline/mature'' than the older one. In the present study, Fourier transform infrared micros pectroscopy (FTIRM) was applied to the study of human osteonal and cor tical bone from iliac crest biopsies of untreated osteoporotic patient s. The hypothesis tested was that osteoporotic bone mineral is monoton ically different in its properties expressed as ''crystallinity/maturi ty'' than the normal. The results indicate significant differences in the mineral properties as expressed by crystal size and perfection, wi th the mineral from osteoporotic bone being more crystalline/mature th an the normal.