Association Between Muscle Morphology Changes, Cervical Spine Degeneration, and Clinical Features in Patients with Chronic Nonspecific Neck Pain: A Magnetic Resonance Imaging Analysis.

OBJECTIVE: The primary objective of the present study was to investigate the correlations among cervical paraspinal muscle morphology changes (fatty infiltration [FI] and muscle atrophy), cervical degeneration, and clinical features in patients with chronic nonspecific neck pain (CNSNP). METHODS: The magnetic resonance imaging data for 55 consecutive patients (average age, 35.80 years) with CNSNP were analyzed in the present cross-sectional study. The muscle morphology changes in 7 groups of paraspinal muscles, indicated by the adjusted cross-sectional area (aCSA) and FI ratio (FI%), were measured from C3/4 to C6/7. The correlations of these changes with disc degeneration, cervical balance (C2-C7 angle and cervical alignment), and clinical features (severity of neck pain and related disability and frequency of acute neck pain recurrence) were evaluated. RESULTS: Significant correlations between FI% and aCSA and the grade of disc degeneration were observed in specific muscle groups at each level (P < 0.05). Morphological changes in the deep extensors and superficial paraspinal muscles were significantly associated with the cervical balance parameters (P < 0.05). The FI% showed a significant positive correlation, and the aCSA showed a significant negative correlation with the severity of neck pain and related disability (P < 0.05). Correlations between the morphological changes and the frequency of acute neck pain recurrence were also present in specific muscles (P < 0.05). CONCLUSIONS: Correlations among the muscle morphology changes, cervical degeneration, and clinical features were established for patients with CNSNP. Muscle volume changes and FI might affect CNSNP diversely through different paraspinal muscle groups. These results imply a complex contribution of muscle morphological changes to cervical degeneration and the clinical course of CNSNP.