A cross-sectional study.
To investigate and compare any morphological differences in paraspinal muscles (PSM) between adolescent idiopathic scoliosis (AIS) patients (with severe or non-severe curves) and healthy controls.
Several studies have reported abnormalities in biochemical, electromyographic activity, and histological changes of PSM in AIS. However, these studies only had qualitative data and without comparison with controls. Changes of muscle mass and mean density at the lumbar region have been described for scoliotic spines. All these findings suggested that imbalance of PSM in AIS could be a contributing factor to the development of severe scoliotic curve.
T2-weighted MR images with multi-planar reconstruction were acquired in 41 Chinese AIS girls with a primary right-sided thoracic curve and 23 age-matched controls. In AIS, measurements of PSM were taken on both concavity and convexity of scoliosis starting from two vertebrae above and two below the apex. Morphological assessments of the multifidus (MF) and erector spinae (ES) muscles on both sides were made including signal intensity (SI) and fat deposition using manual tracing and thresholding technique, respectively. Same parameters were measured in controls at matched vertebrae. One-way analysis of variance (ANOVA) and Pearson correlation tests were used for statistical analysis.
Abnormalities were found at concavity of muscles between AIS and controls. Significantly higher SI and fatty components was observed in AIS at MF muscles on concavity than controls (P-value <0.001). Additionally, SI at MF muscles was significantly correlated with Cobb angle.
Increased SI and fatty components are asymmetrically present in PSM at apex in AIS. Our results showed higher intensity in PSM at concavity in AIS when compared with controls. There was a significant linear correlation between abnormal muscle signal and scoliotic curve. Above features are suggestive of altered muscle composition in concave PSM, possibly due to prolonged compression and reduced muscle activity of PSM caused by the spinal deformity.
Level of Evidence: 4
This study sought to quantitatively compare the morphological change of paraspinal muscles between adolescent idiopathic scoliosis patients with various curve severity of thoracic curve and normal controls. Overall, higher signal intensity and fatty infiltration was found in the concavity paraspinal muscles, which also positively correlated with severity of the curve.
∗Department of Imaging and Interventional Radiology, Faculty of Medicine, The Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong SAR
†Department of Orthopaedics and Traumatology, Faculty of Medicine, The Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
Address correspondence and reprint requests to Winnie Chiu Wing Chu, MD, Department of Imaging and Interventional Radiology, Faculty of Medicine, The Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong SAR; E-mail: email@example.com
Received 13 December, 2018
Revised 4 February, 2019
Accepted 28 March, 2019
The manuscript submitted does not contain information about medical device(s)/drug(s).
The General Research Funding of Hong Kong (Project no. 411910) grant funds were received in support of this work.
No relevant financial activities outside the submitted work.