Prospective multicenter study. To identify radiographic or magnetic resonance (MR) images of fresh vertebral fractures that can predict a high risk for delayed union or nonunion of osteoporotic vertebral fractures (OVFs). Vertebral body fractures are the most common fractures in osteoporosis patients. Conservative treatments are typically chosen for OVFs, and associated back pain generally subsides within several weeks with residual persistent deformity of the vertebral body. In some patients, OVF healing is impaired and correlated with prolonged back pain. However, assessments such as plain radiograph or MR images taken during the early phase to predict high risks for nonunions of OVFs and/or poor prognoses have not been identified. A total of 350 OVF patients from 25 institutes were enrolled in this clinical study. Plain radiograph and MR images of the OVFs were routinely taken at enrollment at the respective institutes. The findings on the plain radiograph and MR images were classified after enrollment in the study. All the patients were treated conservatively without any surgical intervention. After a 6-month follow-up, the patients were classified into two groups, a union group and a nonunion group, depending on the presence of an intravertebral cleft on plain radiograph or MR images. The associations of the images from the first visit with those of the corresponding nonunions at the 6-month follow-up were analyzed by multivariate logistic regression to elucidate specific image characteristics that may predict a high risk for nonunion of OVFs. Forty-eight patients (49 vertebrae) among the 350 patients (363 vertebrae) were classified as nonunions, indicating a nonunion incidence of 13.5% for conventional conservative treatments for OVFs. The statistical analyses revealed that a vertebral fracture in the thoracolumbar spine, presence of a middle-column injury, and a confined high intensity or a diffuse low intensity area in the fractured vertebrae on T2-weighted MR images were significant risk factors for nonunion of OVFs. The results of this study revealed significant relationships between plain radiograph and MR images of acute phase OVFs and the incidence of nonunion. As these risk factors are defined more clearly and further validated, they may become essential assessment tools for determining subsequent OVF treatments. Patients with one or more of the earlier-described risk factors for nonunion should be observed carefully and provided with more intensive treatments.

Study Design. A prospective observational study. Objective. To evaluate the paravertebral muscle (PVM) degeneration in patients with degenerative lumbar scoliosis (DLS), using magnetic resonance imaging. Summary of Background Data. 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. Methods. 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. Results. 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. Conclusion. 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.