Assessment of bone quantity and distribution in adult lumbar scoliosis: new dual-energy x-ray absorptiometry methodology and analysis.

STUDY DESIGN

In this study, we elucidated the bone quantity and distribution in lumbar spines of a group of 176 postmenopausal women (average age 72 years) with scoliosis.

SUMMARY OF BACKGROUND DATA

Adolescent idiopathic scoliosis is associated with a low bone mineral density, but the bone mineral density in adult lumbar scoliosis has not been well-characterized.

METHODS

Dual-energy x-ray absorptiometry analysis of the femoral neck and lumbar spines of 176 postmenopausal women were used to assess the bone mineral density and bone mineral content at both anatomic sites. Subsegmental analysis was used to determine the bone distribution within the lumbar vertebrae.

RESULTS

The lumbar spine bone mass was greater than the femoral neck as evidenced by the average lumbar spine and femoral neck T-scores, -0.493 and -1.81, and Z-scores, 1.70 and 0.12, respectively. There was also a significant correlation between the lumbar spine bone mineral density and femoral neck bone mineral density (r2 = 0.24, P < 0.0001). Individual analysis of 655 vertebrae after bisection and trisection showed that the bone mineral density of the concave side was 15% to 20% higher than the convex, and the difference between the 2 sides was at least as great for patients with low femoral neck bone mineral density as those with high femoral neck bone mineral density.

CONCLUSIONS

The quantity and distribution of bone in adult scoliosis is markedly different from adolescent scoliosis. The lumbar spine bone mass is much greater than the femoral neck, and the concave side bone mass is greater than the convex. Finally, subsegmental vertebral dual-energy x-ray absorptiometry analysis may have wider applications in research and clinical settings.