S. Jaovisidha et al., INFLUENCE OF SPONDYLOPATHY ON BONE DENSITOMETRY USING DUAL-ENERGY X-RAY ABSORPTIOMETRY, Calcified tissue international, 60(5), 1997, pp. 424-429
Spinal cord injury (SCI), as well as other neuromuscular disorders, no
t only results in osteopenia but also induces various patterns of osse
ous, articular, and soft tissue alterations. In the spinal column, a v
ariety of abnormalities occur. To evaluate the magnitude of discrepanc
y of bone densitometry results caused by spondylopathy in SCI patients
, we analyzed anteroposterior (AP) radiographs of the lumbar spine [ob
tained within 1 month of dual energy X-ray absorptiometry (DXA)] in 11
6 SCI patients for various manifestations of spondylopathy, and matche
d the result to each vertebral level (L1, 2, 3, 4). The dataset was st
ratified by individual vertebra (totally 463 vertebrae) as valid (no d
emonstrable other abnormal density on plain radiograph except osteopen
ia), abnormal without, and abnormal with hardware. The influence of sp
ondylopathy on bone densitometry results was determined by the analysi
s of variance (ANOVA) and post hoc analysis. Our results showed that 2
27 (49%) vertebrae were abnormal. Significant elevation (15%, 15%, 18%
, 20%; P < 0.001-P < 0.05) of bone mineral density (BMD; g/cm(2)) was
observed at all levels (L1, 2, 3, 4, respectively), particularly at th
ose abnormal vertebrae without hardware compared with valid (no other
abnormal density on radiograph except osteopenia (Table 1). The L4 lev
el was most severely affected. We concluded that in SCI patients, owin
g to various secondary progressive skeletal abnormalities, particularl
y neuropathic spondylopathy, can have strongly and significantly eleva
ted vertebral bone densitometry results, which can obscure underlying
osteoporosis, leading to misinterpretation and underestimation of frac
ture risk. DXA, although characterized by improving spatial resolution
, cannot replace radiography in establishing the magnitude of this ske
letal pathology. Therefore, determination of bone density in this regi
on with corresponding plain radiographs is highly recommended.