An assessment of morphological and pathological changes in paravertebral muscle degeneration using imaging and histological analysis: a cross-sectional study.

BACKGROUND: The high signal of paravertebral muscle (PVM) on T2-weighted image (T2WI) is usually considered to be fatty degeneration. However, it is difficult to distinguish inflammatory edema from fatty degeneration on T2WI. The purpose of this study was to identify different types of PVM high signal in patients with low back pain (LBP) through magnetic resonance imaging (MRI) and histology. METHODS: Seventy patients with LBP underwent MRI. The signal change of multifidus both on T2WI and fat suppression image (FSI) was quantified by Image J. Furthermore, 25 of the 70 patients underwent surgery for degenerative lumbar disease and their multifidus were obtained during the operation. Histological analysis of the samples was performed by HE staining. RESULT: Three types of PVM signal changes were identified from the MRI. Type 1 (n = 36) indicated fatty degeneration characterized by a high signal on T2WI and low signal on FSI. High signal on both T2WI and FSI, signifying type 2 meant inflammatory edema (n = 9). Type 3 (n = 25) showed high signal on T2WI and partial signal suppression on FSI, which meant a combination of fatty degeneration and inflammatory edema. Histological results were consistent with MRI. Among the 25 patients who underwent surgery, type 1 (n = 14) showed adipocytes infiltration, type 2 (n = 3) showed inflammatory cells infiltration and type 3 (n = 8) showed adipocytes and inflammatory cells infiltration. CONCLUSION: From our results, there are three types of pathological changes in patients with PVM degeneration, which may help to decide on targeted treatments for LBP.

Assessment of the cross-sectional areas of the psoas major in patients with adolescent idiopathic scoliosis before skeletal maturity.

BACKGROUND: The psoas major (PM) can support the lumbar spine and plays an important role in lumbar movement and maintaining lumbar curvature. PURPOSE: To analyze morphological changes of PM and its relation with the severity of adolescent idiopathic scoliosis (AIS). MATERIAL AND METHODS: The study was conducted on patients with AIS (age range = 10-18 years) with primary lumbar scoliosis. The cross-sectional area (CSA) of the PM at the L1-L5 levels were measured. The CSA of the PM in patients with AIS was compared with the average CSA of the PM in age-matched controls. The difference in PM at the apical vertebrae level was compared with the Cobb angle to determine the association between PM imbalance and severity of scoliosis. RESULTS: The CSA of the PM was larger on the concave side than the convex side at the apical vertebrae level and other lumber levels. Patients with a larger Cobb angle had statistically higher PM imbalance at the apical vertebrae level. The CSA of the PM on both the concave and convex sides of patients with AIS were larger than the average CSA of controls aged 16-18 years; however, there was no significant difference between patients with AIS and controls aged 10-15 years. CONCLUSION: There is a significant PM imbalance in patients with AIS before skeletal maturity, and the imbalance is related to the severity of scoliosis. The morphology of PM changed with the progression of scoliosis.