Asymmetric degeneration of paravertebral muscle and psoas muscle in patients with adult degenerative scoliosis and its relationship with coronal spinopelvic parameters

English Keywords:Adult degenerative scoliosis  Paravertebral muscle  Psoas muscle  Coronal imbalance

English Abstract:

  【Abstract】 Objectives: To analyze the asymmetric degeneration of paravertebral muscle and psoas muscle and its relationship with the radiological spinopelvic parameters in coronal plane in patients with adult degenerative scoliosis(ADS), so as to provide a new idea for the evaluation and prediction of coronal imbalance in patients with ADS. Methods: A retrospective analysis of 96 patients with ADS was performed. The muscle values at the apex level of the curvature, including cross-sectional area(CSA), fat saturation fraction(FSF), ratio of CSAconcave to CSAconvex(rCSA), ratio of FSFconcave to FSFconvex(rFSF) were measured on lumbar magnetic resonance imaging. The spinopelvic parameters, including coronal Cobb angle(CA) and coronal balance distance(CBD) were measured on standing radiograph of the entire spine. According to the relative position of C7PL and CSVL, patients with CBD≥30mm were divided into two groups: group A(C7PL on the convex side) and group B(C7PL on the concave side). Paired-sample t-test was used to analyze the difference between the values of muscles on concave and convex side. Pearson correlation was used to analyze the correlation between the asymmetric degeneration of the muscles and the coronal spinopelvic parameters. Results: At the apex level of the curvature, CSA of the multifidus muscle, erector spinae, psoas muscle, and paravertebral muscle on the concave side were significantly larger than those on the convex side(P<0.05). FSFconcave of the multifidus muscle was significantly larger than FSFconvex(P<0.01). FSFconvex of the erector spinae was significantly larger than FSFconcave(P<0.05). There was no significant difference between FSF of the psoas muscle and the paravertebral muscle on both sides(P>0.05). CA was negatively correlated with CSA convex of the multifidus muscle, bilateral CSA of the erector spinae and the paraspinal muscle(r=-0.233, -0.346, -0.211, -0.387, -0.232, P<0.05) and positively correlated with FSFconcave of the multifidus muscle, rCSA of multifidus muscle and paravertebral muscle(r=0.360, 0.424, 0.259, P<0.05). There was no correlation between CBD in group A(13 patients) and the values of each muscle(P>0.05). CBD in group B(9 patients) was positively correlated with CSAconcave of the erector spinae, FSFconcave of the psoas muscle, rCSA of the multifidus muscle, the erector spinae, the psoas muscle and the paravertebral muscle, rFSF of the psoas muscle(r=0.720, 0.768, 0.720, 0.752, 0.738, 0.721, 0.893, P<0.05). Conclusions: There is a significant correlation between the values of paravertebral and psoas muscle in the ADS patients and the spinopelvic coronal parameters. The rCSA of the multifidus muscle has the strongest correlation with CA, and the correlation between rFSF of the psoas muscle and CBD in patients with CBD≥30mm and C7PL on the concave side is the strongest. The paravertebral muscle and psoas muscle could reflect the degree of coronal imbalance of ADS patients.