Ultrasound elastography: the new frontier in direct measurement of muscle stiffness.

Study design An integrated review of current knowledge about the biopsychosocial model of back pain for understanding etiology, prognosis, and interventions, as presented at the plenary sessions of the XII International Forum on LBP Research in Primary Care (Denmark; October 17-19, 2012). Objective To evaluate the utility of the model in reference to rising rates of back pain-related disability, by identifying (a) the most promising avenues for future research in biological, psychological, and social approaches, (b) promising combinations of all 3 approaches, and (c) obstacles to effective implementation of biopsychosocial-based research and clinical practice. Summary of background data The biopsychosocial model of back pain has become a dominant model in the conceptualization of the etiology and prognosis of back pain, and has led to the development and testing of many interventions. Despite this back pain remains a leading source of disability worldwide. Methods The review is a synthesis based on the plenary sessions and discussions at the XII International Forum on LBP Research in Primary Care. The presentations included evidence-based reviews of the current state of knowledge in each of the 3 areas (biological, psychological, and social), identification of obstacles to effective implementation and missed opportunities, and identification of the most promising paths for future research. Results Although there is good evidence for the role of biological, psychological, and social factors in the etiology and prognosis of back pain, synthesis of the 3 in research and clinical practice has been suboptimal. Conclusion The utility of the biopsychosocial framework cannot be fully assessed until we truly adopt and apply it in research and clinical practice. Level of evidence N/A.

Twenty-five years with the biopsychosocial model of low back pain-is it time to celebrate? A report from the twelfth international forum for primary care research on low back pain.

Background Lumbar muscle dysfunction due to pain might be related to altered lumbar muscle structure. Macroscopically, muscle degeneration in low back pain (LBP) is characterized by a decrease in cross-sectional area and an increase in fat infiltration in the lumbar paraspinal muscles. In addition microscopic changes, such as changes in fiber distribution, might occur. Inconsistencies in results from different studies make it difficult to draw firm conclusions on which structural changes are present in the different types of non-specific LBP. Insights regarding structural muscle alterations in LBP are, however, important for prevention and treatment of non-specific LBP. Objective The goal of this article is to review which macro- and/or microscopic structural alterations of the lumbar muscles occur in case of non-specific chronic low back pain (CLBP), recurrent low back pain (RLBP), and acute low back pain (ALBP). Study design Systematic review. Setting All selected studies were case-control studies. Methods A systematic literature search was conducted in the databases PubMed and Web of Science. Only full texts of original studies regarding structural alterations (atrophy, fat infiltration, and fiber type distribution) in lumbar muscles of patients with non-specific LBP compared to healthy controls were included. All included articles were scored on methodological quality. Results Fifteen studies were found eligible after screening title, abstract, and full text for inclusion and exclusion criteria. In CLBP, moderate evidence of atrophy was found in the multifidus; whereas, results in the paraspinal and the erector spinae muscle remain inconclusive. Also moderate evidence occurred in RLBP and ALBP, where no atrophy was shown in any lumbar muscle. Conflicting results were seen in undefined LBP groups. Results concerning fat infiltration were inconsistent in CLBP. On the other hand, there is moderate evidence in RLBP that fat infiltration does not occur, although a larger muscle fat index was found in the erector spinae, multifidus, and paraspinal muscles, reflecting an increased relative amount of intramuscular lipids in RLBP. However, no studies were found investigating fat infiltration in ALBP. Restricted evidence indicates no abnormalities in fiber type in the paraspinal muscles in CLBP. No studies have examined fiber type in ALBP and RLBP. Limitations Lack of clarity concerning patient definitions, exact LBP symptoms, and applied methods. Conclusions The results indicate atrophy in CLBP in the multifidus and paraspinal muscles but not in the erector spinae. No atrophy was shown in RLBP and ALBP. Fat infiltration did not occur in RLBP, but results in CLBP were inconsistent. No abnormalities in fiber type in the paraspinal muscles were found in CLBP. Key words Low back pain, non-specific, chronic, recurrent, acute, muscle structure, fat infiltration, cross-sectional area, fiber type, review.

Structural Changes of Lumbar Muscles in Non-specific Low Back Pain: A Systematic Review.

Lumbar muscle structure and function in chronic versus recurrent low back pain: a cross-sectional study.

Muscle fat fractions derived from multi-echo three-dimensional MR imaging closely match those from MR spectroscopy.

Quantification of Muscle Fat in Patients with Low Back Pain: Comparison of Multi-Echo MR Imaging with Single-Voxel MR Spectroscopy

Dynamic changes of elasticity, cross-sectional area, and fat infiltration of multifidus at different postures in men with chronic low back pain.

Electromyography (EMG) and ultrasonography have been widely used for skeletal muscle assessment. Recently, it has been demonstrated that the muscle thickness change collected by ultrasound during contraction, namely sonomyography (SMG), can also be used for assessment of muscles and has the potential for prosthetic control. In this study, the performances of one-dimensional sonomyography (1D SMG) and surface EMG (SEMG) signal in tracking the guided patterns of wrist extension were evaluated and compared, and the potential of 1D SMG for skeletal muscle assessment and prosthetic control was investigated. Sixteen adult normal subjects including eight males and eight females participated in the experiment. The subject was instructed to perform the wrist extension under the guidance of displayed sinusoidal, square and triangular waveforms at movement rates of 20, 30, 50 cycles per min. SMG and SEMG root mean squares (RMS) were collected from the extensor carpi radialis, respectively, and their RMS errors in relation to the guiding signals were calculated and compared. It was found that the mean RMS tracking errors of SMG under different movement rates were 18.9% +/- 2.6% (mean+/-SD), 18.3% +/- 4.5%, and 17.0% +/- 3.4% for sinusoidal, square and triangular guiding waveforms, while the corresponding values for SEMG were 30.3% +/- 0.4%, 29.0% +/- 2.7% and 24.7% +/- 0.7%, respectively. Paired t test showed that the RMS errors of SMG tracking were significantly smaller than those of SEMG. Significant differences in RMS tracking errors of SMG among the three movement rates (p<0.01) for all the guiding waveforms were also observed using one-way analysis of variance (ANOVA). The results suggest that SMG signal, based on further improvement, has great potential to be an alternative method to SEMG to evaluate muscle function and control prostheses.

Performances of One-Dimensional Sonomyography and Surface Electromyography in Tracking Guided Patterns of Wrist Extension

Liver fibrosis is a kind of chronic damage of the liver The progression of liver fibrosis will result cirrhosis which is one of the top 10 causes of death in the western world Recently, a device developed based on transient ultrasound elastography, named as Fibroscan, shows promising results with high accuracy and good reproducibility However, this device does not provide visual guidance for the liver being tested during measurement We aim to design and validate a transient elastography system with real-time B-mode imaging for liver fibrosis assessment Our development is based on a conventional B-mode ultrasound scanner, which consists of a B-mode ultrasound probe fixed along the axis of a mechanical vibrator The induced shear wave propagates through the liver tissue During measurement, B-mode ultrasound imaging with a frame rate of 30 f/s is generated in real-time to view the morphological information of the tissue, and an A-mode ultrasound with a frame rate of 6000 f/s is generated to track the propagation of shear wave at a selected location The propagation speed of the shear wave is related to the tissue stiffness and Young’s modulus is calculated The system was tested using a series of custom-made phantoms with different stiffness and the results were compared with those measured by Fibroscan For phantom A1, the Young’s modulus is 324 kPa and 354 kPa obtained by Fibroscan and our system, respectively For phantom A2, the modulus is 159 kPa and 198 kPa, respectively For the preliminary in vivo assessment, the Young’s modulus of a normal male subject is 58 kPa and 75 kPa obtained by Fibroscan and our system, respectively In summary, we have successfully developed a transient ultrasound elastography system with real-time B-mode imaging for the assessment of liver fibrosis

Jun Feng He

Papers

Dynamic changes of elasticity, cross-sectional area, and fat infiltration of multifidus at different postures in men with chronic low back pain.

Performances of One-Dimensional Sonomyography and Surface Electromyography in Tracking Guided Patterns of Wrist Extension

Liver Fibrosis Assessment Using Transient Elastography Guided with Real-Time B-Mode Ultrasound Imaging