RESUMO
Although ultrasound measurements have been used in previous studies on carpal tunnel syndrome to visualize injury to the median nerve, whether such ultrasound data can indicate the severity of carpal tunnel syndrome remains controversial. The cross-sectional areas of the median nerve at the tunnel inlet and outlet can show swelling and compression of the nerve at the carpal. We hypothesized that the ratio of the cross-sectional areas of the median nerve at the carpal tunnel inlet to outlet accurately reflects the severity of carpal tunnel syndrome. To test this, high-resolution ultrasound with a linear array transducer at 5-17 MHz was used to assess 77 patients with carpal tunnel syndrome. The results showed that the cut-off point for the inlet-to-outlet ratio was 1.14. Significant differences in the inlet-to-outlet ratio were found among patients with mild, moderate, and severe carpal tunnel syndrome. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.29 between mild and more severe (moderate and severe) carpal tunnel syndrome patients with 64.7% sensitivity and 72.7% specificity. The cut-off point in the ratio of cross-sectional areas of the median nerve was 1.52 between the moderate and severe carpal tunnel syndrome patients with 80.0% sensitivity and 64.7% specificity. These results suggest that the inlet-to-outlet ratio reflected the severity of carpal tunnel syndrome.
RESUMO
BACKGROUND: With aging, the human fracture risks gradually increase. This is mainly due to the corresponding changes of the biomechanical parameters of human bone presents with aging. We measured the microstructural parameters of lumbar bone from women in several age groups by micro-computed tomography and scanning electron microscopy. We observed changes in lumbar cancellous bone mineral density and in biomechanical parameters with aging to elucidate the relationship between age and risk of fracture. We provide theoretical support for human pathology, fracture risk increased with age and the individualized of each age group. METHODS: Thirty-two fresh L3 vertebral bodies were donated from 32 women, aged 20-59 years and were divided into four age groups: 20 to 29 years (group A); 30 to 39 years (group B); 40 to 49 years (group C); and 50 to 59 years (group D). Conventional lumbar separation was performed by removing soft tissue and subsidiary structures, leaving only the vertebral body. The vertebral body was cut into halves along the median sagittal plane, maintaining the upper and lower end-plates of each half, and used for biomechanical, morphological, and density measurements. RESULTS: Comparing group A to B, the rod-like trabecular thickness (Tb.Th) decreased; the trabecular spacing (Tb.Sp) increased; the plate-like Tb.Th decreased; bone mineral density, tissue mineral density, bone volume fraction, and bone surface fraction decreased, and the elastic modulus and the ultimate stress decreased (all changes P < 0.05). Similar significant (P < 0.05) trends were obtained when comparing group C to D. With aging, the collagen cross-linking capacity declined, the thickness of the collagen fibrils was variable (ranging from almost the same to loose, sparse, or disordered), and the finer collagen fibrils between the thick filaments were disorganized. CONCLUSIONS: In women aged 20 to 59 years, the rod-like and plate-like Tb.Th of the vertebral body decreased, while Tb.Sp increased. Additionally, the density, elastic modulus, and ultimate stress of the cancellous bone decreased with age. These associated changes in bone microstructure, density, and biomechanics with age may lead to an increasing risk of osteoporosis and fracture.
