Bone mineral density and bone mineral content in the lumbar vertebrae and the vetebra's biomechanical properties
- VernacularTitle:中老年人腰椎椎体区域性骨密度差异与力学特性的关系
- Author:
Feng-Dong ZHAO
;
Shun-Wu FAN
;
Xian-Jun DING
;
Yue HUANG
;
- Publication Type:Journal Article
- Keywords:
Vertebral endplates;
Fractures;
Bone mineral density;
Bone mineral content;
Failure load
- From:
Chinese Journal of Physical Medicine and Rehabilitation
2003;0(07):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To determine the variation of bone mineral density(BMD)and bone mineral content (BMC)in cadaveric lumbar vertebrae and investigate their significance in determining fracture modes and biomecha- nical properties.Methods The lumbar motion segments of the spines of 19 cadavers(mean age:56 years)were compressed to failure.The BMD and BMC of the cranial and caudal endplates were determined,along with the BMD and BMC of the upper and lower 1/3 transverse sub-endplate layers and the middle 1/3 transverse layer.The anteri- or,middle and posterior 1/3 vertical parts,anterior and posterior 1/2 vertical parts and the whole BMD and BMC were measured by using dual energy X-ray absorptiometry as well.All the data were analyzed statistically.Results Among the 19 segments,macrography after dissection revealed that 16 had been fractured,about 84.2%.The frac- ture always occurred in the centre or in the anterior part of the endplate.Within a vertebral body,the BMD and BMC of the cranial endplate were less than those of the caudal endplate,and the cranial 1/3 transverse layer and middle layer had lower BMD and BMC readings than the caudal layer.For the vertical region,from the anterior 1/3 to the posterior 1/3,or from the anterior 1/2 to the posterior 1/2,the BMD and BMC increased.For the endplate around the disc,the BMD of upper endplate was higher than that of the lower one,but the BMCs were equal.In one motion segment,the failure load correlated positively with BMD,and with the BMC of the endplate and the sub-endplate bone.Conclusion The variations in BMD and BMC within a vertebra and around a disc can explain why vertebral fractures are concentrated on the upper endplate,and why compressive fractures are always wedge-shaped.This un- derstanding can assist in the placement of inter-vertebral spacers.
