ORIGINAL ARTICLE Regional variations of vertebral trabecular bone microstructure with age and gender H. Chen & S. Shoumura & S. Emura & Y. Bunai Received: 5 September 2007 / Accepted: 5 February 2008 / Published online: 11 March 2008 # International Osteoporosis Foundation and National Osteoporosis Foundation 2008 Abstract Summary The vertebral trabecular bone has a complex three-dimensional (3D) microstructure, with inhomoge- neous morphology. A thorough understanding of regional variations in the microstructural properties is crucial for evaluating age- and gender-related bone loss of the vertebra, and may help us to gain more insight into the mechanism of the occurrence of vertebral osteoporosis and the related fracture risks. Introduction The aim of this study was to identify regional differences in 3D microstructure of vertebral trabecular bone with age and gender, using micro-computed tomog- raphy (micro-CT) and scanning electron microscopy (SEM). Methods We used 56 fourth lumbar vertebral bodies from 28 women and men (57–98 years of age) cadaver donors. The subjects were chosen to give an even age and gender distribution. Both women and men were divided into three age groups, 62-, 77- and 92-year-old groups. Five cubic specimens were prepared from anterosuperior, anteroinfe- rior, central, posterosuperior and posteroinferior regions at sagittal section. Bone specimens were examined by using micro-CT and SEM. Results Reduced bone volume (BV/TV), trabecular number (Tb.N) and connectivity density (Conn.D), and increased structure model index (SMI) were found between ages 62 and 77 years, and between ages 77 and 92 years. As compared with women, men had higher Tb.N in the 77- year-old group and higher Conn.D in the 62- and 77-year- old groups. The central and anterosuperior regions had lower BV/TV and Conn.D than their corresponding poster- oinferior region. Increased resorbing surfaces, perforated or disconnected trabeculae and microcallus formations were found with age. Conclusion Vertebral trabeculae are microstructurally het- erogeneous. Decreases in BV/TV and Conn.D with age are similar in women and men. Significant differences between women and men are observed at some microstructural parameters. Age-related vertebral trabecular bone loss may be caused by increased activity of resorption. These findings illustrate potential mechanisms underlying verte- bral fractures. Keywords Aging . Micro-CT . Microstructural properties . Regional variation . Scanning electron microscopy . Vertebral body Introduction Osteoporosis and its associated bone fractures have become an increasingly important public health problem due to Osteoporos Int (2008) 19:1473–1483 DOI 10.1007/s00198-008-0593-3 H. Chen (*) Department of Anatomy, Gifu University Graduate School of Medicine, 1-1 Yanagido, Gifu 501-1194, Japan e-mail: huayue@gifu-u.ac.jp S. Shoumura Department of Physical Therapy, Chubu Gakuin University School of Rehabilitation, Gifu 501-3993, Japan S. Emura Nursing Course, Gifu University School of Medicine, Gifu 501-1194, Japan Y. Bunai Department of Legal Medicine, Gifu University Graduate School of Medicine, 1–1 Yanagido, Gifu 501-1194, Japan