[Radiological comparison of bilateral paravertebral muscles in degenerative lumbar scoliosis and its potential importance].

Objectives: To investigate the radiological change of bilateral paravertebral muscles in degenerative lumbar scoliosis (DLS) and analyze its clinical significance.

Methods: As a retrospective study, 66 patients with DLS and 66 patients with lumbar spinal stenosis were retrospectively enrolled from April 2004 to August 2011 as scoliosis group and lumbar spinal stenosis group, meanwhile 66 health persons with no lumbar spinal stenosis were selected as control group. No significant differences were found in the gender, age and body mass index among the three groups. The cross-sectional area (CSA) and percentage of fat infiltration area (FIA) of the bilateral paravertebral muscles at the L(1)-S(1) levels were measured using T2-weighted axial MRI and Image J software. The measured data were analyzed with a paired t-test.

Results: In the DLS with bilateral symptom group, the mean percentage of FIA of the multifidus muscle on the convex side were 18% ± 4%, 21% ± 4%, 27% ± 4%, 34% ± 6%, 42% ± 10% and on the concave side were 25% ± 8%, 30% ± 7%, 35% ± 7%, 40% ± 10%, 44% ± 8% at L(1-2), L(2-3), L(3-4), L(4-5) and L(5)-S(1) levels, which showed significant differences between the convex side and the concave side (t = 7.95, 9.30, 5.35, 2.78, 2.38, P < 0.05); the mean percentage of FIA of the longissimus muscle on the convex side were 25% ± 9%, 28% ± 8% and on the concave side were 27% ± 9%, 31% ± 9% at L(3-4), L(4-5) levels, which showed significant differences between the convex side and the concave side (t = 2.52, 3.48, P < 0.05). There were no significant differences in the CSA of both muscles between the concave and convex sides (P > 0.05). In the DLS with unilateral symptom group, the mean percentage of FIA of the multifidus muscle on the convex side were 18% ± 5%, 23% ± 5%, 29% ± 5%, 34% ± 6%, 42% ± 9% and on the concave side were 23% ± 6%, 30% ± 7%, 36% ± 7%, 41% ± 10%, 45% ± 8% at L(1-2), L(2-3), L(3-4), L(4-5) and L(5)-S(1) levels, which showed significant differences between the convex side and the concave side (t = 6.67, 7.96, 6.43, 3.86, 2.15, P < 0.05). There were on significant differences in the CSA of both muscles, and in the percentage of FIA of the longissimus between the concave and convex sides (P > 0.05).

Conclusions: There exist asymmetric degeneration in paravertebral muscle in DLS, which have potential clinical importance on the evaluation of curve progression, and muscle degeneration is more often seen in the concave side. Spinal deformity and radiculopathy may contribute to the paravertebral muscle degeneration.