The role of paraspinal muscle degeneration in coronal imbalance in patients with degenerative scoliosis

Abdukahar Kiram; Zongshan Hu; Gene Chi-Wai Man; Hongru Ma; Jie Li; Yanjie Xu; Zhikai Qian; Zezhang Zhu; Zhen Liu; Yong Qiu

doi:10.21037/qims-22-222

The role of paraspinal muscle degeneration in coronal imbalance in patients with degenerative scoliosis

Quant Imaging Med Surg. 2022 Nov;12(11):5101-5113. doi: 10.21037/qims-22-222.

Authors

Abdukahar Kiram¹, Zongshan Hu¹, Gene Chi-Wai Man², Hongru Ma¹, Jie Li¹, Yanjie Xu¹, Zhikai Qian³, Zezhang Zhu^{1

3}, Zhen Liu^{1

3}, Yong Qiu^{1

3}

Affiliations

¹ Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China.
² Department of Orthopedics and Traumatology, The Faculty of Medicine, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
³ Department of Spine Surgery, Nanjing Drum Tower Hospital, the Clinical College of Nanjing Medical University, Nanjing, China.

Abstract

Background: Coronal imbalance in degenerative scoliosis is common and is highly correlated with health-related quality of life. Paraspinal muscle is critical to spine stability, but little is known about its contribution to coronal imbalance in degenerative scoliosis. This study aims to investigate the relationship between paraspinal muscle (PSM) degeneration and coronal imbalance in patients with degenerative scoliosis (DS).

Methods: This is a retrospective cohort study. A total of 117 patients with DS were retrospectively reviewed. Parameters of PSM (bilateral cross-sectional area, CSA; fat infiltration rate, FI%) at the apical disc and adjacent levels were quantitatively evaluated using MRI. Standing whole-spine radiograph was used to evaluate the coronal (Cobb angle, CA; coronal balance distance, CBD) and sagittal (thoracic kyphosis, TK; lumbar lordosis, LL; sagittal vertical axis, SVA) parameters. Patients were divided into 3 groups: coronal balanced (Type A), coronal imbalanced shifting to concavity (Type B), and coronal imbalanced shifting to convexity (Type C).

Results: Based on our criteria, 56 patients were assigned to Type A, 34 patients to Type B, and 27 patients to Type C. There was no significant difference on the sagittal profiles and CSA between the groups. However, Type A showed significantly lower FI% than Type B and Type C on both concavity and convexity (Concave side: Type A vs. Type B vs. Type C, 30.8±8.1 vs. 45.1±7.7 vs. 38.7±12.5, P=0.001; Convex side: Type A vs. Type B vs. Type C, 32.6±10.9 vs. 46.3±7.3 vs. 40.7±11.8, P=0.004). Specifically, Cobb angle was negatively correlated with CSA, mainly at convexity (R=-0.415, P=0.008). Similarly, the increase of CBD significantly correlated with FI% at concavity (R=0.491, P=0.001) and convexity (R=0.354, P=0.025).

Conclusions: DS patients with coronal imbalance demonstrated a worse PSM degeneration when compared with those without coronal imbalance. Besides, PSM degeneration strongly correlated with coronal imbalance, which implies that PSM degeneration may contribute to the coronal imbalance in patients with DS.

Keywords: Degenerative scoliosis (DS); adult spinal deformity; coronal imbalance; fat infiltration rate; paraspinal muscle (PSM).