Affiliations: [a] Department of Orthopedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China | [b] Key Laboratory of Biotherapy of Zhejiang Province, Hangzhou, Zhejiang, China | [c] Department of Radiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
Correspondence:
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Corresponding author: Z.J. Hu, Department of Orthopedics Surgery, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, 3 East Qingchun Road, Hangzhou 310016, Zhejiang, China. Tel.: +86 057186006367; Fax: +86 057186044817; E-mail: xuwbgk@hotmail.com
Abstract: BACKGROUND: Many studies have explored the relationship between
facet tropism and facet joint osteoarthritis, disc degeneration and
degenerative spondylolisthesis. However, the associations between facet
orientation and tropism, and paraspinal muscles have not been studied. OBJECTIVE: To analyze the associations between facet orientation
and tropism, and parameters of paraspinal muscles in patients with chronic
low back pain. METHODS: Ninety-five patients with chronic low back pain were
consecutively enrolled. Their facet joint angles were measured on computed
tomography (CT) while gross cross-sectional area (GCSA), functional
cross-sectional area (FCSA) and T2 signal intensity of lumbar
paraspinal and psoas muscle were evaluated on magnetic resonance imaging
(MRI). RESULTS: The GCSA and FCSA were significantly smaller for
multifidus muscle (P< 0.001), but significantly larger for erector spinae and
psoas muscles (P< 0.001), in coronally-orientated group than those in
sagittally-orientated group. The differences of bilateral GCSA and FCSA of
multifidus muscle were significantly larger in facet tropism group than
those in no facet tropism group (P= 0.009 and P= 0.019). CONCLUSIONS: Muscular asymmetries may develop in the lumbar region
of the spine, which are associated with facet asymmetry in patients with
chronic low back pain. Longitudinal studies are needed to understand the
causal relationship between facet orientation and tropism and muscular
asymmetry in future.
