Muscle Density and Bone Quality of the Distal Lower Extremity Among Individuals with Chronic Spinal Cord Injury

Abstract

Background:Understanding the related fates of muscle density and bone quality after chronic spinal cord injury (SCI) is an important initial step in determining endocrine-metabolic risk. Objective: To examine the associations between muscle density and indices of bone quality at the distal lower extremity of adults with chronic SCI. Methods: A secondary data analysis was conducted in 70 adults with chronic SCI (C2-T12; American Spinal Injury Association Impairment Scale .9]) (P < .05), whereas cLEMS was most strongly associated with TbBMD (b = 7.69 [4.63, 10.76]) (P < .001). Conclusion: Muscle density and function were most strongly associated with TbBMD at the distal tibia in adults with chronic SCI, whereas muscle size was most strongly associated with bone size and geometry at the tibial shaft. Key words: bone mineral density, bone quality, muscle density, muscle size, osteoporosis, peripheral quantitative computed tomography, spinal cord injury S pinal cord injury (SCI) is associated with sublesional muscle atrophy, 1-3 changes in muscle fiber type, 4,5 reductions in hip and knee region bone mineral density (BMD), [6][7][8] and increased central and regional adiposity after injury.9,10 Adverse changes in muscle and bone health in individuals with SCI contribute to an increased risk of osteoporosis, 11-13 fragility fractures, 14 and endocrine-metabolic disease (eg, diabetes, dyslipidemia, heart disease).15-17 Crosssectional studies have shown a higher prevalence of lower extremity fragility fractures among individuals with SCI ranging from 1% to 34%. [18][19][20] Fragility fractures are associated with negative health and functional outcomes, including an increased risk of morbidity and hospitalization, 21,22 mobility limitations, 23 and a reduced quality of life.

Massive Edema of the Lower Limbs in Patients after Spinal Cord Injury—One Picture, Different Diagnoses

“…The formation of a hematoma may be associated with injury to the muscles during exercises or a complication of anticoagulant use [ 14 ]. The muscles in patients after SCI may be atrophied and change depending on fiber type [ 15 ]. Yeung [ 16 ] described three cases of huge IHs in patients after SCI.…”

Resistance Isn't Futile: The Physiological Basis of the Health Effects of Resistance Exercise in Individuals With Type 1 Diabetes

“…Indeed, bone architecture depends critically on muscle CSA and tension development (94), whilst muscle immobilization, and/or detraining leads to bone mass loss (95). Moreover, exercises that require large rates of muscular force cause greater bone-related benefits than do isometric or low force exercises (94, 96–98). Conversely, extreme endurance and/or low load bearing activities may exasperate the degradation of bone quality and health (99, 100).…”

Peripheral Quantitative Computed Tomography: Review of Evidence and Recommendations for Image Acquisition, Analysis, and Reporting, Among Individuals With Neurological Impairment

“…These voxel size settings (0.4 x 0.4 mm or 0.5 x 0.5 mm for assessment of the radius and tibia, and 0.3 x 0.3 mm for assessment of the femur allow sufficiently accurate determination of bone densities of both bone compartments (108,118) and detection of cortical bone thicker than 2.0 -2.5 mm (101,119) . With voxel size reduced to 0.2 x 0.2 mm for epiphyseal sites; with use of a dedicated software, bone micro-architecture (bone volume fraction, trabecular number, trabecular separation and trabecular thickness) can be roughly estimated (73,74,117,120) .…”