Search

PURPOSE: Osteoporosis in individuals with spinal cord injury (SCI) is associated with pathological fractures, renal stone formation, and overall decreased health quality. Most of the loss of bone mineral density (BMD) occurs within the first 6-8 months following spinal cord injury. We examined the extent to which the lumbar spine, the proximal femur, distal femur, and proximal tibia lose BMD in individuals with chronic SCI as compared to individuals without paralysis. SUBJECTS: Twenty-two individuals participated in the study. Eleven subjects had previously sustained a spinal cord injury (mean=14 years) (SCI GROUP) while eleven subjects were without spinal cord injury (NON-SCI GROUP). METHODS AND MATERIALS: The two groups were not different in age, height, or weight. Each subject had the lumbar spine, bilateral hips, bilateral distal femurs, and bilateral proximal tibias scanned using Dual Energy X-ray Absorptiometry (DEXA-Hologic QDR 2000). Analytical software developed for the hip and spine (Hologic) was used. The distal femur and proximal tibia were analyzed with the lumbar spine software while using a newly developed measurement protocol. Four raters analyzed the distal femur and proximal tibia using the newly devised protocol. ANALYSES AND RESULTS: The BMD was decreased for the proximal femur in the SCI GROUP when compared to the NON-SCI GROUP (2 X ANOVA p [is less than] . 05). Conversely, the BMD was not different (p=0.15) between the SCI GROUP and the NON-SCI GROUP for the lumbar spine. The BMD was decreased in the SCI GROUP when compared to the NON-SCI GROUP for the distal femur and proximal tibia. There was high agreement among raters ((ICC (2,1)) = 0.98) for the protocol used to assess distal femur and proximal tibia. CONCLUSIONS: The protocol developed to assess bone density of the proximal tibia and distal femur is highly reliable. BMD is decreased in the hip, femur, and tibia in individuals with SCI but is unchanged in the lumbar spine when compared to age matched controls. These findings suggest that loading the lumbar spine while sitting maintains the bone density and supports the theory that loss of bone density after SCI is attributable to loss of mechanical loading. This work was supported by a grant from the Paralyzed Veterans of America Spinal Cord Research Foundation., Shields RK, Clark SD, Grant SA, Tysseling VM, Zwart BD, Schindler-Ivens S, Littmann A; Physical Therapy Graduate Program, The University of Iowa, Iowa City, IA, [...]