Publications (2)4.5 Total impact
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ABSTRACT: A prospective observational study. To evaluate the paravertebral muscle (PVM) degeneration in patients with degenerative lumbar scoliosis (DLS), using magnetic resonance imaging. Several studies have described the histological and morphological changes to the PVM in patients with chronic low back pain and lumbar radiculopathy. However, there is little knowledge about the PVM changes in patients with DLS. Fifty-seven patients with lumbar spinal stenosis (LSS) with DLS (DLS group) and 50 control patients with LSS without DLS (LSS group) were examined. The cross-sectional area (CSA) and percentage of fat infiltration area (%FIA) of the bilateral multifidus and longissimus muscles at the L1-S1 levels were measured using T2-weighted axial magnetic resonance imaging and computer software. A multifidus muscle biopsy and histological evaluation were performed in some patients. In the DLS group, the CSA of the multifidus muscle was significantly smaller and the %FIA of both muscles was significantly higher on the concave side than on the convex side at all levels (P < 0.0001 for each). These differences were also found in the longissimus muscles at the L4-L5 and L5-S1 levels (P < 0.0001 for each). Histologically, the multifidus muscle exhibited reductions in the muscle fiber size and number of nuclei on the concave side. In the LSS group, the total CSA and %FIA did not differ significantly between the left and right sides. However, in patients with unilateral radiculopathy, the CSA of the multifidus muscle was significantly smaller (P < 0.05) and the %FIA of both muscles was significantly higher (P < 0.05) on the symptomatic side, especially at 1 level below. This observational study with magnetic resonance imaging and histology showed that muscle degeneration was more common on the concave side in patients with DLS. Radiculopathy and spinal deformity may contribute to the PVM degeneration.
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ABSTRACT: Histopathological and immunohistochemical analysis. To investigate the histological changes and expression of bone morphogenetic protein (BMP) signaling component in hypertrophied ligamentum flavum (LF), and to clarify the effect of mechanical stress on them. Hypertrophic changes of the LF are a major factor in degenerative lumbar canal stenosis (DLCS), but their mechanism remains unclear. BMPs are growth factors that regulate many cellular processes including proliferation, differentiation, and extracellular matrix synthesis. However, a few studies have investigated the expressions of BMP signaling in the hypertrophied LF. A total of 133 LF specimens from patients with DLCS and 17 control LF specimens from patients with lumbar disc herniation were analyzed histologically using hematoxylin and eosin, elastica van Gieson, and toluidine blue staining. To analyze the influence of mechanical stress, the DLCS specimens were divided into 2 groups: DLCS with and DLCS without hypermobility groups. The LF thickness was measured by magnetic resonance image, and the correlations between the thickness and the histological data were analyzed. Immunohistochemical analyses were carried out to confirm the expressions and localizations of BMP signaling components. The cell number and cartilage matrix area were significantly increased in the hypertrophied LF, and those changes were more obvious in DLCS with hypermobility than in DLCS without hypermobility. The cellularity and percentage of cartilage matrix area had positive linear correlations with the LF thickness. BMP receptors and BMP ligands were both expressed by many cells of the hypertrophied LF, and some of these cells were positive for Sox9, CD105, and Msx2. The percentage of immunopositive cells for each BMP receptor type was significantly higher in DLCS with hypermobility than in DLCS without hypermobility. Higher cellularity and increased cartilage matrix area are important changes in LF hypertrophy. These results suggest that BMP signaling and mechanical stress may play a role in the hypertrophied LF.