Lumbar muscle involvement in the occurrence of osteoporotic vertebral fracture.

Objective: 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.

Methods: 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).

Results: 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 mm.m, respectively = 0.015), but there was no significant difference in the PM (746.92 ± 197.89 versus 731.74 ± 215.53 mm.m, respectively = 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, 0.001; PVM: 1.93 ± 0.5 versus 1.74 ± 0.5, = 0.003) and a lower average muscle density (PM: 26.99 ± 12.83 versus 33.91 ± 8.12 HU, 0.001; PVM: 3.42 ± 21.06 versus 12.94 ± 18.88 HU, 0.001).

Conclusion: 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.