CT and MRI of spinal neuroarthropathy.

OBJECTIVE: The objective of this article is to describe the different stages of spinal neuroarthropathy as assessed by CT and MRI and to discuss their contribution to the management of affected patients. CONCLUSION: Early-stage findings consisted of inflammatory changes involving adjacent vertebral endplates and mimicking degenerative disk disease with inflammation. Subsequently, progression of the lesions led to complete destruction of the intervertebral joint. Knowledge of the initial features of spinal neuroarthropathy may allow earlier treatment, which may improve outcomes.

Isolated vertebral metastasis with a fluid-fluid level from a poorly differentiated adenocarcinoma.

Fluid-fluid level in bone metastases is an extremely rare finding, with only five case reports published in the literature. Here we report a case of an atypical isolated bone metastasis presenting with a fluid-fluid level revealing lung cancer in a 47-year-old patient without history of cancer. The differential diagnosis and imaging features are discussed with reference to the relevant literature.

Panton-valentine leukocidin enhances the severity of community-associated methicillin-resistant Staphylococcus aureus rabbit osteomyelitis.

BACKGROUND: Extensive spread of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in the United States, and the concomitant increase in severe invasive staphylococcal infections, including osteomyelitis, in healthy children, has led to renewed interest in Panton-Valentine leukocidin (PVL). However, the pathogenetic role of PVL in staphylococcal infections remains controversial, possibly because it depends on the site of infection. METHODOLOGY/PRINCIPAL FINDINGS: We compared the course of experimental rabbit osteomyelitis due to the PVL-positive CA-MRSA strain USA 300 (LAC) and its PVL-negative isogenic derivative (LACDeltapvl), using a low and a high inoculum (8x10(5) and 4x10(8) CFU). With the low inoculum, bone infection was less frequent on day 7 (D7) and day 28 (D28) with LACDeltapvl than with LAC (respectively 12/19 and 18/19 animals, p = 0.042). With the high inoculum of both strains, all the animals were infected on D7 and the infection persisted on D28 in almost every case. However, tibial bacterial counts and the serum CRP concentration fell significantly between D7 and D28 with LACDeltapvl but not with LAC. Respectively 67% and 60% of LAC-infected rabbits had bone deformation and muscle/joint involvement on D7, compared to 0% and 7% of LACDeltapvl-infected rabbits (p = 0.001 and p = 0.005 respectively). Between D0 and D28, the anti-PVL antibody titer increased significantly only with the high inoculum of LAC. CONCLUSIONS/SIGNIFICANCE: PVL appears to play a role in the persistence and rapid local extension of rabbit osteomyelitis, in keeping with the greater severity of human bone infections due to PVL-positive S. aureus. The possible therapeutic implications of these findings are discussed.

Osteoporotic vertebral collapse: percutaneous vertebroplasty and local kyphosis correction.

Forty-six cases of osteoporotic vertebral collapse (27 thoracic, 19 lumbar) were treated by means of percutaneous vertebroplasty in a hyperlordosis position. Institutional review board approval and informed consent were obtained. Kyphosis reducibility was preprocedurally estimated from the angular difference between neutral and hyperlordosis positions. Effective reduction was the angular difference in neutral positions before and after vertebroplasty. Reduction (< or =14 degrees ; mean, 6.43 degrees) was obtained in cases with estimated reducibility greater than 5 degrees (31 cases, 67%), which is a 34% (6.5 degrees of 19.1 degrees ) mean reduction. A significantly greater level of kyphosis reduction was observed in cases with intravertebral clefts (20 cases, 43%) at hyperlordosis than in those without (7.2 degrees vs 4.9 degrees ; P < .01). Vertebroplasty may reduce kyphosis due to localized collapsed vertebrae; intravertebral mobility and cleft suggest this possibility.

End plate marrow changes in the asymptomatic lumbosacral spine: frequency, distribution and correlation with age and degenerative changes.

PURPOSE: To investigate the frequency and distribution of end plate marrow signal intensity changes in an asymptomatic population and to correlate these findings with patient age and degenerative findings in the spine. MATERIALS AND METHODS: MR imaging studies of the lumbosacral (LS) spine in 59 asymptomatic subjects were retrospectively reviewed by 2 musculoskeletal radiologists to determine the presence and location of fat-like and edema-like marrow signal changes about the end plates of the L1-2 through L5-S1 levels. The presence of degenerative changes in the spine was recorded as was patient age. Descriptive statistics were utilized to determine the frequency and associations of end plate findings and degenerative changes in the spine. Interobserver variability was determined by a kappa score. Binomial probability was used to predict the prevalence of the end plate changes in a similar subject population. The Fisher exact test was performed to determine statistical significance of the relationship of end plate changes with degenerative changes in the spine, superior versus inferior location about the disc and age of the patient population. RESULTS: Focal fat-like signal intensity adjacent to the vertebral end-plate was noted in 15 out of 59 subjects by both readers, and involved 38 and 36 out of 590 end plates by readers 1 and 2, respectively. Focal edema-like signal intensity adjacent to the vertebral end plate was noted in 8 out of 59 subjects by both readers and involved 11 and 10 out of 590 end plates by readers 1 and 2, respectively. Either fat or edema signal intensity occurred most often at the anterior ( p<.05) aspects of the mid-lumbar spine and was seen in an older sub-population of the study ( p<.05). CONCLUSION: End plate marrow signal intensity changes are present in the lumbar spine of some asymptomatic subjects with a characteristic location along the spine and in vertebral end plates.

Anterior cruciate ligament reconstruction with bioabsorbable polyglycolic acid interference screws: MR imaging follow-up.

PURPOSE: To examine at magnetic resonance (MR) imaging the degradation of an interference screw made of polyglycolic acid (67.5%) and trimethylene carbonate (32.5%) and compare the MR findings with the clinical evaluation results. MATERIALS AND METHODS: Clinical and MR imaging studies were performed concomitantly 6 months (in 20 patients), 1 year (in 10 patients), and 2 years (in eight patients) after surgery. Screw resorption rate, tibial tunnel appearance and contents, epiphyseal reaction, reconstructed ligament appearance, bone plug healing, joint effusion, and synovitis were evaluated. RESULTS: The screw was observed to be partially resorbed (by approximately one-third) at 6 months and totally resorbed at 1 year. Enhancement of the tunnel content, which can be linked to bone healing and screw replacement, was seen without a surrounding inflammatory reaction. Bone tunnel enlargement was observed and remained stable over time; this phenomenon has often been reported with metallic or polylactic acid interference screws and could be due to the position of the screw within the tunnel. The tissue that was seen at MR imaging to be replacing the screw was either fibrous or fatty and fibrous but never bone. CONCLUSION: Resorption of the screw does not appear to be related to clinical results.