Background: Trabeculae in vertebral bodies are unequally distributed within the cervical spine (CS), the thoracic spine (TS), and lumbar spine (LS). Such structures are also unequally distributed within the individual vertebrae. Exact knowledge of the microstructure of these entities could impact our understanding and treatment of fractures caused by osteoporosis and possibly improve surgical approaches. Appropriate investigations could help clarify the pathomechanisms of different forms of osteoporotic vertebral fractures, as well as different changes in morphological findings like the trabecular bone score (TBS). In the present study, we applied punctures to the craniocaudal and ventrocaudal directions and obtained cylinders of cancellous bone from the central portions and marginal regions of cervical vertebrae 5 and 6, thoracic vertebrae 8 and 12, and lumbar vertebrae 1 and 3. We systematically analyzed these samples to determine the bone volume fraction, trabecular thickness, separation, connectivity density, degree of anisotropy, and structure model index. Methods: Using an 8-gauge Jamshidi needle, we obtained samples from three quadrants (Q I: right margin; Q II: central; Q III: left margin) in the frontal and transverse plane and prepared these samples with a moist cloth in a 1.5 mL Eppendorf reaction vessel. The investigations were performed on a micro-CT device (SKYSCAN 1172, RJL Micro & Analytic Company, Karlsdorf-Neuthard, Germany). All collected data were analyzed using the statistical software package SPSS (version 24.0, IBM Corp., Armonk, NY, USA). Student’s t test, the Wilcoxon–Mann–Whitney test, the Chi-squared test, and univariate analysis were used for between-group comparisons. The selection of the test depended on the number of investigated groups and the result of the Shapiro–Wilk test of normal distribution. In the case of statistically significant results, a post hoc LSD test was performed. Results: In total, we obtained 360 bone samples from 20 body donors. The craniocaudal puncture yielded data of similar magnitudes for all investigated parameters in all three quadrants, with the highest values observed in the CS. Comparisons of the ventrodorsal and craniocaudal microstructure revealed a significantly lower trabecular density and a significantly higher degree of anisotropy in the craniocaudal direction. Conclusions: The results presented different distributions and behaviors of trabecular density, with lower density in the mid-vertebral region over the entire breadth of the vertebrae. Reduced trabecular density caused a higher degree of anisotropy and was, therefore, associated with a lower capacity to sustain biomechanical loads. Fractures in fish vertebrae were easily explained by this phenomenon. The different changes in these structures could be responsible, in part, for the changes in the TBS determined using dual-energy X-ray absorptiometry. These results confirm the clinical relevance of the TBS.

Introduction: Comparative studies on Hounsfield units (HU) and bone volume fraction (BVF%) for the demonstration of cancellous bone density in the entire spine and in the various intravertebral regions are rare. The aim of the present study was to determine HU in various segments and sectional planes (sagittal, axial, coronary) of the spine and their description in the context of bone density measurement on micro-CT, as well as the significance of the values for bone loss and fracture risk. Materials/Methods: The spines of 11 body donors were analyzed by means of high-resolution spiral CT and micro-CT. Vertebral deformities were identified on sagittal reformations and classified. Cancellous bone density in the individual vertebrae from C3 to L5, expressed in HU, was measured on CT images (in all 242 vertebral bodies). For this purpose, a manually positioned ROI was established in mid-vertebral cancellous bone in the axial, sagittal, and coronary planes. Using a Jamshidi^® needle, we obtained 726 specimens from prepared vertebrae extracted from three quadrants (QI: right-sided edge, QII: central, QIII: left-sided edge) and analyzed these on a micro-CT device (SKYSCAN 1172, RJL Micro & Analytic GmbH, Germany). The study design with multiple measurements was reflected by a General Linear Model Repeated Measures. The model was adjusted to the bone density values of both procedures (HU, BVF%) in the viewed sectional planes and quadrants for 22 vertebrae, with the predictors gender and fracture status, controlled for age and body mass index (BMI). Analysis of variance provided estimations of density values and comparisons of several subgroups. Results: All spines were osteoporotic. Both procedures revealed a significant reduction in cancellous bone density from C3 to L5 (p ≤ 0.018). Gender (p = 0.002) and fracture status (p = 0.001) have an impact on bone density: men have higher bone density values than women; cases with fewer fractures also have higher bone density values. CT revealed both effects (p = 0.002 for each) with greater clarity. HU on CT measurements in the axial plane showed higher density values than in the sagittal or coronary planes. CT measurement profiles along the spine as well as along the individual profiles of the 11 body donors were independent of the measured quadrants, but the micro-CT measurements were not. Discussion: The craniocaudal reduction in bone density was demonstrated in different degrees of clarity by the two procedures. Likewise, the procedure-related visualization of differences in cancellous bone density between genders, fracture groups, sectional planes, and quadrants indicates the need for a better understanding of the advantages of each procedure for patient-oriented approaches to the diagnosis of osteoporosis. Future research should be focused on the determination of standard values and their clinical application for the prevention and treatment of osteoporosis.

Zusammenfassung: Einleitung Die vorliegende Studie hatte das Ziel, Erkenntnisse über Veränderungen in der Knochendichte und der kortikalen Dicke bei Patienten mit diffuser idiopathischer skelettaler Hyperostose (DISH) und Osteoporose zu gewinnen, um das Verständnis für Risikobereiche für das Auftreten von Insuffizienzfrakturen am Achsenskelett zu verbessern. Fallbeschreibung und Ergebnisse Eine weibliche 83-Jährige Körperspenderin mit DISH und Osteoporose wurde mittels CT/QCT- sowie Mikro-CT-Bildgebung untersucht. Die kortikale Dicke wurde an den Endplatten und der kortikalen Schale von 15 Wirbelkörpern an 1800 Messpunkten ermittelt, um Unterschiede zwischen den Wirbelsäulen Abschnitten festzustellen. Alle erhobenen Daten wurden mit dem Softwarepaket SPSS, Version 24.0 (Armonk, New York: IBM Corp., USA) analysiert. Es zeigte sich eine signifikant höhere kortikale Dicke in der Brustwirbelsäule im Vergleich zur Hals- (p=0,001) und Lendenwirbelsäule (p<0,001). Die Kortikalisdicke ist an der Hinterkante in den verschiedenen Abschnitten am geringsten ausgeprägt. Der spongiöse Knochenmineralgehalt steigt in den von DISH betroffenen Wirbelkörpern an. Obwohl die Halswirbelsäule nicht von DISH betroffen war, fand sich dort die höchste Knochendichte der gesamten Wirbelsäule. Schlussfolgerungen Die signifikant höhere kortikale Dicke und der erhöhte spongiöse Knochenmineralgehalt in der Brustwirbelsäule bei DISH könnte auf eine erhöhte Stabilität und ein geringeres Frakturrisiko in diesem Bereich hinweisen. Die hohe Knochendichte im HWS-Bereich scheint auch bei vorliegender Osteoporose am Achsenskelett einen kritischen Frakturschwellenwert nicht zu unterschreiten.