Measurement of anisotropic vertebral trabecular bone loss during aging by quantitative image analysis

Abstract

Age-dependent variations in the architecture of vertebral trabeculae in both the vertical and horizontal planes were characterized by quantitative image analysis. Images were obtained from autopsy specimens of the third lumbar vertebrae in 61 subjects (30 men and 31 women) whose ages ranged between 33 and 89 years). All subjects had died acutely either after trauma or illnesses unrelated to the skeleton. Using mathematical morphology techniques, we measured total bone area and perimeter, and the width of trabecular particles and medullary spaces in each slice. Between the age intervals 33-49 and 80-89 years: total bone loss in the vertical and horizontal planes was 51 and 64% for women, and 38 and 29% for men, respectively. Mean trabecular width (MTW) in the vertical plane decreased from 172 to 128 micron in women and from 181 to 144 micron in men; MTW in the horizontal plane fell from 144 to 112 micron in women and remained at 114 micron in men. Maximum trabecular width decreased with age in both planes in both sexes. The mode for trabecular width was 111 micron in both sexes for all ages and in both planes. The total number of trabeculae decreased only for women in the vertical plane. Intertrabecular spaces enlarged reciprocally as the trabeculae became thinner, but the widening of spaces was much greater than that expected with trabecular thinning alone. We conclude that age-related bone loss is comprised of two processes: reduction of MTW and fragmentation and complete loss of some trabeculae. We found no evidence of vertical trabeculae thickening during normal aging.

Age-related changes in trabecular bone microstructures: global and local morphometry

“…Increased Tb.Sp implies a decrease in Tb.N, which was found in earlier studies where shortening or complete loss of trabeculae was documented [18,28]. In another study, it was found that the Tb.N decreased significantly with age for both horizontal and vertical trabeculae [27].…”

“…Opposed to Tb.Sp, Tb.Th is of higher controversy and has thoroughly been investigated by means of two-dimensional (2-D) and 3-D methods. In some studies, it was found that the mean Tb.Th decreased significantly with age either in all trabeculae [28][29][30] or in horizontal trabeculae only [25,27] whereas in other studies, no significant decrease could be observed [12,22]. Other studies even speculated that vertical elements that are subjected to compression could increase in thickness as a compensatory response to loss of horizontal trabeculae [24,63].…”

“…It was also proposed that a potential thinning of residual elements could arise from incomplete refilling by osteoblasts of resorption cavities of normal or reduced size [24]. This theory stimulated research in trabecular bone structure related to aging, and different methods were used to investigate the thickness and spacing of trabecular elements [25][26][27][28][29][30].…”

Age-Related Bone Loss: Old Bone, New Facts

“…Reductions in trabecular volume, number, and width have been well documented in specimens of older bone [13,14]. These alterations are due to a variety of factors, including Chan/Duque changes in gonadal status, nutrition, and physical activity.…”

Experimental validation of finite element predicted bone strain in the human metatarsal

“…For trabecular bone, the number and thickness of the trabeculae are decreased, and the size of the intertrabecular spaces increase (113)(114)(115)(116). As transverse struts of the trabecular become thinner and fail, the anisotropy increases with age (112,117), and the longitudinal struts become more likely to buckle (118).…”