Lumbar muscle involvement in the occurrence of osteoporotic vertebral fracture

To determine if a lumbar musculature deficiency (paravertebral - PVM - and psoas - PM - muscles) is associated with a higher prevalence of vertebral fractures in osteoporotic patients.

To constitute the fracture group, data were collected retrospectively from patients with one or more recent osteoporotic vertebral fractures between T10 and L5 such as non-injected computerized tomography (CT), dual-energy X-ray absorptiometry (DXA). A control group was made by matching the patients on age, bone mineral density measured by DXA and gender. We analyzed PM and PVM atrophy based on cross-sectional area (CSA) adjusted to the body area as well as fatty infiltration on a 3-level scale and the average muscle density in Hounsfield units (HU).

One hundred seventeen patients were included in each group. The fracture group had a lower PVM CSA than the control group (2197.92 ± 460.19 versus 2335.20 ± 394.42 mm².m^-2, respectively p = 0.015), but there was no significant difference in the PM (746.92 ± 197.89 versus 731.74 ± 215.53 mm².m^-2, respectively p = 0.575). The fracture group had a higher grade of fatty infiltration than the control group (PM: 1.3 ± 0.46 versus 1.07 ± 0.25, p < 0.001; PVM: 1.93 ± 0.5 versus 1.74 ± 0.5, p = 0.003) and a lower average muscle density (PM: 26.99 ± 12.83 versus 33.91 ± 8.12 HU, p < 0.001; PVM: 3.42 ± 21.06 versus 12.94 ± 18.88 HU, p < 0.001).

This study shows an association between a lack of axial musculature and the occurrence of osteoporotic vertebral fractures. Preventive strengthening exercises could be proposed to osteoporotic patients.