HETEROGENEITY OF THE SKELETON - COMPARISON OF THE TRABECULAR MICROARCHITECTURE OF THE SPINE, THE ILIAC CREST, THE FEMUR, AND THE CALCANEUS

The objective of this study was to elucidate the structure of cancello us bone and its age-related changes at different skeletal sites. There fore, the lumbar spine, iliac crest, femur, and calcaneus of 12 age- a nd sex-matched skeletal healthy autopsy cases (6 females, 6 males, age d 28-84 years, mean 54 years) were removed. The following analysis inc ludes an evaluation of the trabecular bone volume (BV/TV, %) and the t rabecular interconnection (TBPf, mm(-1)) as well as a qualitative inve stigation of the structure of trabecular bone. BV/TV shows the followi ng mean values: lumbar spine, 83% (+/-0.8%); iliac crest, 11.5% (+/-1. 6%); intertrochanteric, 10.2% (+/-1.2%); femoral neck, 15.8% (+/-1.6%) ; and calcaneus, 15.4% (+/-2.0%). There are significant differences be tween the BV/TV of the femoral neck and that of the lumbar spine as we ll as between that of the calcaneus and the lumbar spine (p < 0.01). H owever, a positive correlation can be seen between the bone mass of th e spine and that of all other investigated sites (r = 0.67 to r = 0.80 ; p(r) < 0.1). The trabecular interconnection of the lumbar spine (2.7 mm(-1), SEM +/- 0.2 mm(-1)) and the femoral neck (0.3 mm(-1), SEM +/- 0.3 mm(-1)) differs significantly. Only these two sites show a signif icant positive correlation of TBPf (r = 0.60; p(r) < 0.1). Age-depende nt alteration of the spine and the femoral neck in bone mass and bone structure is nearly the same. The trabecular microarchitecture of the iliac crest varies systematically. A region 4-10 cm behind and 1-3 cm below the anterior superior iliac spine turns out to be the most suita ble biopsy site because of its closest relation to the lumbar bone mas s, However, drawing information about the trabecular interconnection w ithin the lumbar spine by measurement of the iliac crest at any site s eems to be impossible. The horizontal specimens reveal a vertical runn ing tubular spongiosa pattern that is arranged in concentric rings sta rting from the dorsal shell like a honeycomb. The comparison of TBPf i n horizontal and vertical planes and its age-related changes indicates the age-related bone loss to be predominantly a loss of horizontal tr abeculae. Thus, the presented data provide further information about t he skeletal distribution and heterogeneity of the trabecular microarch itecture.