Muscle functional magnetic resonance imaging and acute low back pain: a pilot study to characterize lumbar muscle activity asymmetries and examine the effects of osteopathic manipulative treatment

Reported biological effects following Osteopathic Manipulative Treatment: A comprehensive mapping review

BACKGROUND AND PURPOSE

Osteopathic Manipulative Treatment (OMT) is a therapeutic whole-body approach mainly focused on correcting somatic dysfunctions. The aim of this scoping review is to systematically map the literature regarding the documented biological effects observed following OMT.

METHODS

The 2020 JBIRM version and the PRISMA-ScR were followed for the conceptualization and reporting of this review. The protocol was registered on the "Open Science Framework Registry" (https://doi.org/10.17605/OSF.IO/MFAUP). We searched for original articles published on Medline, Embase, and Scopus, from inception to the present.

RESULTS

Overall, 10,419 records were identified. After duplicate removal, screening for title and abstract, and specific exclusions with reasons, a total of 146 studies were included. Wide differences were detected among studies in their geographical localization, study design, temporal distribution, participants' condition, OMT protocols, and documented biological effects. Such variety in frequency distribution was properly described through descriptive statistics.

CONCLUSIONS

Biological modifications that appear to be induced by OMT have been detected in several body systems, but mostly in neurophysiological correlates and musculoskeletal changes. Results suggest a growing interest over the years on this topic, especially in the last two decades. More efforts in research are recommended to highlight whether such changes specifically depend on OMT, and to demonstrate its specific contribution to clinical practice.

Decreased Risk of Low Back Pain During Pregnancy Associated With the Use of Orthopedic Manual Therapy: A Nested Case-Control Study

Background

Recent evidence suggests that the use of orthopedic manual therapy (OMT) may lessen the subsequent risk of low back pain (LBP), but this association has not been examined among pregnant women who are at higher risk of LBP. This study aims to determine whether the addition of OMT to conventional LBP treatment before pregnancy could decrease the subsequent risk of LBP during pregnancy.

Methods

From Taiwan's National Health Insurance Research Database, we identified 68,960 women, 20–55 years of age, with first pregnancy between 2001 and 2012. We then performed a nested case-control study in which 3,846 women with newly diagnosed LBP were matched to 3,846 controls according to age and cohort entry year. Multivariate conditional logistic regression was employed to estimate the association between OMT use before pregnancy and LBP during pregnancy.

Results

OMT users had a lower risk of LBP than did non-users, with an adjusted OR of 0.86 (95% CI, 0.78–0.93). Subgroup analysis showed that women with high intensity use of OMT treatment prior to pregnancy reported the lowest level of LBP during pregnancy by nearly 30%.

Conclusion

The pre-pregnancy use of OMT treatment significantly decreased LBP risk during pregnancy, especially with high-intensity use. Thus, clinicians may consider recommending OMT for pregnant women to avoid possible obstetric complications during the pregnancy.

How Does the Measurement of Disability in Low Back Pain Map Unto the International Classification of Functioning, Disability and Health?: A Scoping Review of the Manual Medicine Literature

ABSTRACT

The objective of this study was to catalog items from instruments used to measure functioning, disability, and contextual factors in patients with low back pain treated with manual medicine (manipulation and mobilization) according to the International Classification of Functioning, Disability and Health. This catalog will be used to inform the development of an International Classification of Functioning, Disability and Health-based assessment schedule for low back pain patients treated with manual medicine. In this scoping review, we systematically searched MEDLINE, Embase, PsycINFO, and CINAHL. We identified instruments (questionnaires, clinical tests, single questions) used to measure functioning, disability, and contextual factors, extracted the relevant items, and then linked these items to the International Classification of Functioning, Disability and Health. We included 95 articles and identified 1510 meaningful concepts. All but 70 items were linked to the International Classification of Functioning, Disability and Health. Of the concepts linked to the International Classification of Functioning, Disability and Health, body functions accounted for 34.7%, body structures accounted for 0%, activities and participation accounted for 41%, environmental factors accounted for 3.6%, and personal factors accounted for 16%. Most items used to measure functioning and disability in low back pain patient treated with manual medicine focus on body functions, as well as activities and participation. The lack of measures that address environmental factors warrants further investigation.

Inconsistent descriptions of lumbar multifidus morphology: A scoping review

Background

Lumbar multifidus (LM) is regarded as the major stabilizing muscle of the spine. The effects of exercise therapy in low back pain (LBP) are attributed to this muscle. A current literature review is warranted, however, given the complexity of LM morphology and the inconsistency of anatomical descriptions in the literature.

Methods

Scoping review of studies on LM morphology including major anatomy atlases. All relevant studies were searched in PubMed (Medline) and EMBASE until June 2019. Anatomy atlases were retrieved from multiple university libraries and online. All studies and atlases were screened for the following LM parameters: location, imaging methods, spine levels, muscle trajectory, muscle thickness, cross-sectional area, and diameter. The quality of the studies and atlases was also assessed using a five-item evaluation system.

Results

In all, 303 studies and 19 anatomy atlases were included in this review. In most studies, LM morphology was determined by MRI, ultrasound imaging, or drawings – particularly for levels L4–S1. In 153 studies, LM is described as a superficial muscle only, in 72 studies as a deep muscle only, and in 35 studies as both superficial and deep. Anatomy atlases predominantly depict LM as a deep muscle covered by the erector spinae and thoracolumbar fascia. About 42% of the studies had high quality scores, with 39% having moderate scores and 19% having low scores. The quality of figures in anatomy atlases was ranked as high in one atlas, moderate in 15 atlases, and low in 3 atlases.

Discussion

Anatomical studies of LM exhibit inconsistent findings, describing its location as superficial (50%), deep (25%), or both (12%). This is in sharp contrast to anatomy atlases, which depict LM predominantly as deep muscle. Within the limitations of the self-developed quality-assessment tool, high-quality scores were identified in a majority of studies (42%), but in only one anatomy atlas.

Conclusions

We identified a lack of standardization in the depiction and description of LM morphology. This could affect the precise understanding of its role in background and therapy in LBP patients. Standardization of research methodology on LM morphology is recommended. Anatomy atlases should be updated on LM morphology.

Utilization of MR imaging in myodural bridge complex with relevant muscles: current status and future perspectives

The aim of this study is to review and discuss the literature on the utilization of magnetic resonance imaging (MRI) in investigating the structure and feasible function of the myodural bridge complex (MDBC) with relevant muscles, which will be useful to understand the function of the MDB. The myodural bridge (MDB) is a soft tissue connective bridge that provides a fascial continuity between the musculature/ligament and cervical spinal dura mater (SDM) in the suboccipital areas. All of these involved structures are referred to as the MDBC. It would transfer tensile forces effectively from involved suboccipital muscles/ligament to SDM during head movement. Despite present achievements, its anatomic and functional role is still unclear. MRI enables not only in vivo visualization of ligaments, musculature and spinal dura with conventional T₁W, T₂W and PDW imaging, but also functional evaluation of MDBC with relevant muscles, such as muscles' fatty infiltration, cross-sectional area changes and injuries. Though some functional MRI techniques have not been used for the MDBC with relevant muscles now, these techniques have great potential to better understand function of MDBC including its suspected clinical role. MRI is likely the most powerful tool to study MDBC and relevant muscles with only limited exploration so far.

The relationship between cross-sectional area of multifidus muscle and disability index in patients with chronic non-specific low back pain

BACKGROUND

Nonspecific low back pain (NSLBP) is a common problem that may have an effect on the level of functional ability. Imaging techniques indicated the degeneration of multifidus muscles in patients with low back pain. But its relationship with disability in NSLBP is unclear.

OBJECTIVE

To assess the relationship between changes in multifidus muscle morphology in MRI as paraclinical data with changes in the level of disability as clinical data in patients with CNLBP, whose MRI studies are normal. Moreover, the relationship between multifidus CSA and its thickness was determined.

DESIGN

Cross-sectional study.

METHODS

A total of 45 subjects with CNLBP participated in this study. Multifidus muscle thickness and cross-sectional area (CSA) for both sides in L4-L5 and L5-S1 levels were measured with MRI and Image J software. Level of disability was assessed with Roland-Morris disability index.

RESULTS

There was no significant relationship between multifidus muscle's CSA or thickness variations among the L4-L5 and L5-S1 levels and disability index score. Furthermore, Pearson's test showed significant positive relationship between thickness and CSA of muscles (p˂0.05).

CONCLUSION

The relationship between lumbar multifidus Thickness and disability in CNLBP with normal MRI study, is not proven in this study. Multifidus muscle thickness in L4-L5 or L5-S1 level can be representative of its CSA in patients with CNLBP and normal MRI.

A randomized control trial to determine the effectiveness and physiological effects of spinal manipulation and spinal mobilization compared to each other and a sham condition in patients with chronic low back pain: Study protocol for The RELIEF Study

BACKGROUND

Low back pain (LBP) is one of the most common reasons for seeking medical care. Manipulative therapies are a common treatment for LBP. Few studies have compared the effectiveness of different types of manipulative therapies. Moreover, the physiologic mechanisms underlying these treatments are not fully understood. Herein, we present the study protocol for The Researching the Effectiveness of Lumbar Interventions for Enhancing Function Study (The RELIEF Study).

METHODS AND STUDY DESIGN

The RELIEF Study is a Phase II RCT with a nested mechanistic design. It is a single-blinded, sham-controlled study to test the mechanisms and effectiveness of two manual therapy techniques applied to individuals (n = 162; 18-45 years of age) with chronic LBP. The clinical outcome data from the mechanistic component will be pooled across experiments to permit an exploratory Phase II RCT investigating the effectiveness. Participants will be randomized into one of three separate experiments that constitute the mechanistic component to determine the muscular, spinal, and cortical effects of manual therapies. Within each of these experimental groups study participants will be randomly assigned to one of the three treatment arms: 1) spinal manipulation, 2) spinal mobilization, or 3) sham laser therapy. Treatments will be delivered twice per week for 3-weeks.

DISCUSSION

This data from this will shed light on the mechanisms underlying popular treatments for LBP. Additionally, the coupling of this basic science work in the context of a clinical trial will also permit examination of the clinical efficacy of two different types of manipulative therapies.

Does a Better Perfusion of Deconditioned Muscle Tissue Release Chronic Low Back Pain?

Non-specific chronic low back pain (nsCLBP) is a multifactorial condition of unknown etiology and pathogenesis. Physical and genetic factors may influence the predisposition of individuals to CLBP, which in many instances share a musculoskeletal origin. A reduced pain level in low back pain patients that participate in exercise therapy highlights that disuse-related muscle deconditioning may predispose individuals to nsCLBP. In this context, musculoskeletal pain may be the consequence of capillary rarefaction in inactive muscle as this would lower local tissue drainage and washing out of toxic waste. Muscle activity is translated into an angio-adaptative process, which implicates angiogenic-gene expression and individual response differences due to heritable modifications of such genes (gene polymorphisms). The pathophysiologic mechanism underlying nsCLBP is still largely unaddressed. We hypothesize that capillary rarefaction due to a deconditioning of dorsal muscle groups exacerbates nsCLBP by increasing noxious sensation, reducing muscle strength and fatigue resistance by initiating a downward spiral of local deconditioning of back muscles which diminishes their load-bearing capacity. We address the idea that specific factors such as angiotensin-converting enzyme and Tenascin-C might play an important role in altering susceptibility to nsCLBP via their effects on microvascular perfusion and vascular remodeling of skeletal muscle, inflammation, and pain sensation. The genetic profile may help to explain the individual predisposition to nsCLBP, thus identifying subgroups of patients, which could benefit from ad hoc treatment types. Future therapeutic approaches aimed at relieving the pain associated with nsCLBP should be based on the verification of mechanistic processes of activity-induced angio-adaptation and muscle-perfusion.

Muscle function and size in the lumbar spine before and after a four week exercise intervention

BACKGROUND

Exercise of the spinal muscles is recommended for a variety of rehabilitative reasons but it is not always clear whether interventions are effective in improving the performance of the muscles or whether their benefit is elicited via other mechanisms.

OBJECTIVE

To explore the effects of an exercise intervention on the size and exercise performance of the lumbar spine extensor muscles.

METHODS

Eleven healthy participants undertook a four week programme of exercise. Magnetic resonance imaging and phosphorus spectroscopy were performed before and after the intervention to determine the time to fatigue and phosphocreatine (PCr) depletion during a muscle endurance test (modified Biering-Sørensen) together with muscle cross-sectional area (CSA).

RESULTS

The post intervention measures were significantly different to the pre-intervention results for the time to fatigue (post-pre: 20.5 ± 22.7 s (P= 0.014)) and PCr depletion both at the point of fatigue (post-pre: 9.5 ± 11.9% (P= 0.024)) and at a matched time-point (post-pre: 12.2 ± 11.9% (P= 0.007)). CSA was not significantly different in any muscle.

CONCLUSIONS

Exercise improved the performance of the trunk muscles despite no impact on CSA. This demonstrated the importance of obtaining a wide range of measures when assessing the effectiveness of exercise intervention programmes.

Effects of Myofascial Release in Nonspecific Chronic Low Back Pain: A Randomized Clinical Trial

STUDY DESIGN

Double-blind, randomized parallel sham-controlled trial with concealed allocation and intention-to treat analysis.

OBJECTIVE

To investigate the effects of an isolate myofascial release (MFR) protocol on pain, disability, and fear-avoidance beliefs in patients with chronic low back pain (CLBP).

SUMMARY OF BACKGROUND DATA

MFR is a form of manual medicine widely used by physiotherapists in the management of different musculoskeletal pathologies. Up to this moment, no previous studies have reported the effects of an isolated MFR treatment in patients with CLBP.

METHODS

Fifty-four participants, with nonspecific CLBP, were randomized to MFR group (n = 27) receiving four sessions of myofascial treatment, each lasting 40 minutes, and to control group (n = 27) receiving a sham MFR. Variables studied were pain measured by means Short Form McGill Pain Questionnaire (SF-MPQ) and visual analog scale (VAS), disability measured with Roland Morris Questionnaire, and fear-avoidance beliefs measured with Fear-Avoidance Beliefs Questionnaire.

RESULTS

Subjects receiving MFR displayed significant improvements in pain (SF-MPQ) (mean difference -7.8; 95% confidence interval [CI]: -14.5 to -1.1, P = 0.023) and sensory SF-MPQ subscale (mean difference -6.1; 95% CI: -10.8 to -1.5, P = 0.011) compared to the sham group, but no differences were found in VAS between groups. Disability and the Fear-Avoidance Beliefs Questionnaire score also displayed a significant decrease in the MFR group (P < 0.05) as compared to sham MFR.

CONCLUSION

MFR therapy produced a significant improvement in both pain and disability. Because the minimal clinically important differences in pain and disability are, however, included in the 95% CI, we cannot know whether this improvement is clinically relevant.

LEVEL OF EVIDENCE

2.

Spinal Manipulation Vs Sham Manipulation for Nonspecific Low Back Pain: A Systematic Review and Meta-analysis

OBJECTIVE

The purpose of this systematic review was to identify and critically evaluate randomized controlled trials of spinal manipulation (SM) vs sham manipulation in the treatment of nonspecific low back pain.

METHODS

Four electronic databases were searched from their inception to March 2015 to identify all relevant trials. Reference lists of retrieved articles were hand-searched. All data were extracted by 2 independent reviewers, and risk of bias was assessed using the Cochrane Back Review Group Risk of Bias tool.

RESULTS

Nine randomized controlled trials were included in the systematic review, and 4 were found to be eligible for inclusion in a meta-analysis. Participants in the SM group had improved symptoms compared with participants receiving sham treatment (standardized mean difference = - 0.36; 95% confidence interval, - 0.59 to - 0.12). The majority of studies were of low risk of bias; however, several of the studies were small, the practitioner could not be blinded, and some studies did not conduct intention-to-treat analysis and had a high level of dropouts.

CONCLUSION

There is some evidence that SM has specific treatment effects and is more effective at reducing nonspecific low back pain when compared with an effective sham intervention. However, given the small number of studies included in this analysis, we should be cautious of making strong inferences based on these results.

Asymmetrical and smaller size of trunk muscles in combat sports athletes with lumbar intervertebral disc degeneration

Background

Lumbar intervertebral disc degeneration (LDD) frequently occurs in athletes. Associations between LDD and trunk muscles still remain unclear.

Purpose

This study examined whether there is an association between the prevalence of LDD and the symmetry and size of the cross-sectional areas (CSAs) of the trunk muscles in combat sports athletes.

Methods

Participants in this study were 151 collegiate male combat sports athletes. A total of 755 lumbar intervertebral discs from L1–2 to L5–S1 in 151 athletes were assessed using magnetic resonance imaging (MRI) and a comprehensive grading system of LDD (grades I–V). All 151 athletes were divided into 2 groups: LDD and non-LDD. CSAs of trunk muscles at the L3–4 disc level were measured using MRI.

Results

Sixty-nine athletes had LDD at 1 or more disc levels (45.7 %). The LDD grade for the lower 2 disc levels was significantly higher than that for the other disc levels (p < 0.001). The CSAs of the left and right sides in trunk muscles were significantly asymmetrical, independent of the LDD which was prevalent in the disc levels (obliques: p = 0.040; quadratus lumborum: p < 0.001). The relative CSAs of trunk muscles to their body weight in the LDD group were significantly smaller than those in the non-LDD group (rectus abdominis: p = 0.011; obliques: p = 0.024; quadratus lumborum: p = 0.006; lumbar erector spinae plus multifidus: p = 0.001).

Conclusion

This study suggests that the prevalence of LDD is associated with asymmetrical and relatively smaller CSAs of trunk muscles in combat sports athletes.

Susceptibility to Hamstring Injuries in Soccer: A Prospective Study Using Muscle Functional Magnetic Resonance Imaging

BACKGROUND

Running-related hamstring strain injuries remain a delicate issue in several sports such as soccer. Their unremittingly high incidence and recurrence rates indicate that the underlying risk has not yet been fully identified. Among other factors, the importance of neuromuscular coordination and the quality of interplay between the different hamstring muscle bellies is thought to be a key determinant within the intrinsic injury risk. Muscle functional magnetic resonance imaging (mfMRI) is one of the tools that has been proven to be valid for evaluating intermuscular coordination.

PURPOSE

To investigate the risk of sustaining an index or recurring soccer-related hamstring injury by exploring metabolic muscle characteristics using mfMRI.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 27 healthy male soccer players and 27 soccer players with a history of hamstring injuries underwent standardized mfMRI. The mfMRI protocol consisted of a resting scan, a strenuous bilateral eccentric hamstring exercise, and a postexercise scan. The exercise-related T2 change, or the signal intensity shift between both scans, was used to detect differences in metabolic characteristics between (1) the different hamstring muscle bellies and (2) the prospective cohorts based on the (re)occurrence of hamstring injuries during a follow-up period of 18 months.

RESULTS

The risk of sustaining a first hamstring injury was associated with alterations in the intermuscular hierarchy in terms of the magnitude of the metabolic response after a heavy eccentric effort, with the dominant role of the semitendinosus set aside for a higher contribution of the biceps femoris (P = .017). Receiver operating characteristic (ROC) curve analysis demonstrated that this variable was significantly able to predict the occurrence of index injuries with a sensitivity of 100% and a specificity of 70% when the metabolic activity of the biceps femoris exceeded 10%. The risk of sustaining a reinjury was associated with a substantial deficit in hamstring strength endurance (P = .031). Soccer players who sustained a reinjury were only able to perform prone leg curls for a mean duration of 146.50 ± 76.16 seconds, whereas those with an injury history but no recurrence during follow-up were able to continue for a mean of 237.45 ± 110.76 seconds (95% CI, 11.9-230.5 seconds; P = .031).

CONCLUSION

This was the first study to assess the causal relation between the intramuscular recruitment pattern and the risk of sustaining an index or secondary hamstring strain. Changes in intermuscular interplay seem to significantly increase the risk of sustaining index hamstring injuries in male amateur soccer players. Inadequate eccentric muscle endurance could be associated with an increased risk of sustaining a recurring hamstring injury.

Contribution of each masticatory muscle to the bite force determined by MRI using a novel metal-free bite force gauge and an index of total muscle activity

PURPOSE

To develop a metal-free bite force gauge that can monitor the bite force in a strong magnetic field and to analyze the correlations between bite-force and total T2 shift of the mastication muscles.

MATERIALS AND METHODS

The gauge used a micro-pressure sensor made of optical fiber. Ten subjects performed a 60-s isometric bite task at 40% of maximum clenching in various occlusal support conditions (intact dentition, right molar loss, or left molar loss). Spin-echo images were taken with a 1.5 Tesla scanner before and immediately after the task to correlate the bite force with the mean voxel count, mean shift in transverse relaxation time (ΔT2), and total T2 shift of each masticatory muscle.

RESULTS

Measurements of total T2 shift identified significant correlations between the bite force and activities of the superficial layer of the bilateral masseter muscle, regardless of the occlusion condition (intact dentition: left, P = 0.007 and right, P < 0.001; right molar loss: left, P = 0.02 and right, P = 0.021; and left molar loss: left, P = 0.022 and right, P = 0.049). In contrast, significant correlations were not detected between the bite force and mean ΔT2 (intact dentition: left, P = 0.102 and right, P = 0.053; right molar loss: left, P = 0.393 and right, P = 0.868; and left molar loss: left, P = 0.531 and right, P = 0.92).

CONCLUSION

Measurement of total T2 shift using a metal-free bite force gauge is a more sensitive index of individual muscle activity than mean ΔT2 during a bite task. J. MAGN. RESON. IMAGING 2016;44:804-813.

Biceps femoris and semitendinosus--teammates or competitors? New insights into hamstring injury mechanisms in male football players: a muscle functional MRI study

BACKGROUND

The hamstring injury mechanism was assessed by investigating the exercise-related metabolic activity characteristics of the hamstring muscles using a muscle functional MRI (mfMRI) protocol.

METHODS

27 healthy male football players and 27 football players with a history of hamstring injuries (recovered and playing fully) underwent standardised mfMR Imaging. The mfMRI protocol consisted of a resting scan, a strenuous bilateral eccentric hamstring exercise and a postexercise scan. The exercise-related T2 increase or the signal intensity shift between both scans was used to detect differences in metabolic activation characteristics (1) between the different hamstring muscle bellies and (2) between the injury group and the control group.

RESULTS

A more symmetrical muscle recruitment pattern corresponding to a less economic hamstring muscle activation was demonstrated in the formerly injured group (p<0.05). The injured group also demonstrated a significantly lower strength endurance capacity during the eccentric hamstring exercise.

CONCLUSIONS

These findings suggest that the vulnerability of the hamstring muscles to football-related injury is related to the complexity and close coherence in the synergistic muscle recruitment of the biceps femoris and the semitendinosus. Discrete differences in neuromuscular coordination and activity distribution, with the biceps femoris partly having to compensate for the lack of endurance capacity of the semitendinosus, probably increase the hamstring injury risk.

MRI assessment of paraspinal muscles in patients with acute and chronic unilateral low back pain

OBJECTIVE

To investigate the changes in paraspinal muscle cross-sectional area (CSA) and composition, using the digital data from lumbar spine MRIs of patients with acute and chronic low back pain (LBP).

METHODS

In total, 178 patients with unilateral LBP who had lumbar MRI examination were recruited. The data were obtained by a retrospective documentation audit. The CSAs and mean signal intensities of the bilateral paraspinal muscles [psoas major (PM), quadratus lumborum, multifidus (MF) and erector spinae (ES)] were measured, and the percentage of fat infiltration was calculated. The data between the painful side and non-painful side were compared, and between-group comparisons were tested. 42 patients with chronic unilateral LBP could indicate the problem level, and the CSA and mean signal intensity of the MF muscle were analysed at the problem level, and one vertebral above and one vertebral level below the problem level.

RESULTS

The CSAs of the PM and ES muscles were significantly decreased in the acute LBP group, while in the chronic LBP group, significant reduction in CSA was found in the MF and ES muscles on the painful side compared with the non-painful side. The mean signal intensity and fat content of the ES muscle on the painful side in the chronic LBP group was significantly higher than that on the painful side in the acute LBP group. The significant decrease of CSA in the MF muscle was found at multiple levels on the painful side.

CONCLUSION

The present findings show that there is selective ipsilateral atrophy of paraspinal muscles, specific to the symptomatic side, in patients with acute and chronic LBP. The reduction of the muscle CSA and increased fatty infiltration occurred synchronously, and the extent of change is significantly greater in chronic LBP in the ES muscle. Atrophy of the MF muscle appears to be at multiple levels but side specific in relation to symptoms in patients with chronic LBP, and the decreased muscle CSA may occur prior to fatty infiltration.

ADVANCES IN KNOWLEDGE

There are specific paraspinal muscles undergoing atrophy and fatty infiltration in patients with acute and chronic LBP on the symptomatic side. The CSA of the MF muscle decreased at multiple levels on the symptomatic side in patients with chronic unilateral LBP, which may occur prior to fatty infiltration.

Age-related structural and functional changes of low back muscles

During aging declining maximum force capacity with more or less unchanged fatigability is observed with the underlying mechanisms still not fully understood. Therefore, we compared morphology and function of skeletal muscles between different age groups. Changes in high-energy phosphate turnover (PCr, Pi and pH) and muscle functional MRI (mfMRI) parameters, including proton transverse relaxation time (T2), diffusion (D) and vascular volume fraction (f), were investigated in moderately exercised low back muscles of young and late-middle-aged healthy subjects with (31)P-MR spectroscopy, T2- and diffusion-weighted MRI at 3T. In addition, T1-weighted MRI data were acquired to determine muscle cross-sectional areas (CSA) and to assess fat infiltration into muscle tissue. Except for pH, both age groups showed similar load-induced MR changes and rates of perceived exertion (RPE), which indicates comparable behavior of muscle activation at moderate loads. Changes of mfMRI parameters were significantly associated with RPE in both cohorts. Age-related differences were observed, with lower pH and higher Pi/ATP ratios as well as lower D and f values in the late-middle-aged subjects. These findings are ascribed to age-related changes of fiber type composition, fiber size and vascularity. Interestingly, post exercise f was negatively associated with fat infiltration with the latter being significantly higher in late-middle-aged subjects. CSA of low back muscles remained unchanged, while CSA of inner back muscle as well as mean T2 at rest were associated with maximum force capacity. Overall, applying the proposed MR approach provides evidence of age-related changes in several muscle tissue characteristics and gives new insights into the physiological processes that take place during aging.

Clinical response and relapse in patients with chronic low back pain following osteopathic manual treatment: results from the OSTEOPATHIC Trial

Clinical response and relapse following a regimen of osteopathic manual treatment (OMT) were assessed in patients with chronic low back pain (LBP) within the OSTEOPATHIC Trial, a randomized, double-blind, sham-controlled study. Initial clinical response and subsequent stability of response, including final response and relapse status at week 12, were determined in 186 patients with high baseline pain severity (≥50 mm on a 100-mm visual analogue scale). Substantial improvement in LBP, defined as 50% or greater pain reduction relative to baseline, was used to assess clinical response at weeks 1, 2, 4, 6, 8, and 12. Sixty-two (65%) patients in the OMT group attained an initial clinical response vs. 41 (45%) patients in the sham OMT group (risk ratio [RR], 1.45; 95% confidence interval [CI], 1.11-1.90). The median time to initial clinical response to OMT in these patients was 4 weeks. Among patients with an initial clinical response prior to week 12, 13 (24%) patients in the OMT group vs. 18 (51%) patients in the sham OMT group relapsed (RR, 0.47; 95% CI, 0.26-0.83). Overall, 49 (52%) patients in the OMT group attained or maintained a clinical response at week 12 vs. 23 (25%) patients in the sham OMT group (RR, 2.04; 95% CI, 1.36-3.05). The large effect size for short-term efficacy of OMT was driven by stable responders who did not relapse.

The hypertrophy of the lateral abdominal wall and quadratus lumborum is sport-specific: an MRI segmental study in professional tennis and soccer players

The aim was to determine the volume and degree of asymmetry of quadratus lumborum (QL), obliques, and transversus abdominis; the last two considered conjointly (OT), in tennis and soccer players. The volume of QL and OT was determined using magnetic resonance imaging in professional tennis and soccer players, and in non-active controls (n = 8, 14, and 6, respectively). In tennis players the hypertrophy of OT was limited to proximal segments (cephalic segments), while in soccer players it was similar along longitudinal axis. In tennis players the hypertrophy was asymmetric (18% greater volume in the non-dominant than in the dominant OT, p = 0.001), while in soccer players and controls both sides had similar volumes (p > 0.05). In controls, the non-dominant QL was 15% greater than that of the dominant (p = 0.049). Tennis and soccer players had similar volumes in both sides of QL. Tennis alters the dominant-to-non-dominant balance in the muscle volume of the lateral abdominal wall. In tennis the hypertrophy is limited to proximal segments and is greater in the non-dominant side. Soccer, however, is associated to a symmetric hypertrophy of the lateral abdominal wall. Tennis and soccer elicit an asymmetric hypertrophy of QL.

Psoas syndrome: a frequently missed diagnosis

Psoas syndrome is an easily missed diagnosis. However, it is important to consider this condition as part of the differential diagnosis for patients presenting with low back pain--particularly for osteopathic physicians, because patients may view these practitioners as experts in musculoskeletal conditions. The authors describe the case of a 48-year-old man with a 6-month history of low back pain that had been attributed to "weak core muscles." The diagnosis of psoas syndrome was initially overlooked in this patient. After the correct diagnosis was made, he was treated by an osteopathic physician using osteopathic manipulative treatment, in conjunction with at-home stretches between office treatments. At his 1-month follow-up appointment, he demonstrated continued improvement of symptoms and a desire for further osteopathic manipulative treatment.

Neurophysiologic effects of spinal manipulation in patients with chronic low back pain

Background

While there is growing evidence for the efficacy of SM to treat LBP, little is known on the mechanisms and physiologic effects of these treatments. Accordingly, the purpose of this study was to determine whether SM alters the amplitude of the motor evoked potential (MEP) or the short-latency stretch reflex of the erector spinae muscles, and whether these physiologic responses depend on whether SM causes an audible joint sound.

Methods

We used transcranial magnetic stimulation to elicit MEPs and electromechanical tapping to elicit short-latency stretch reflexes in 10 patients with chronic LBP and 10 asymptomatic controls. Neurophysiologic outcomes were measured before and after SM. Changes in MEP and stretch reflex amplitude were examined based on patient grouping (LBP vs. controls), and whether SM caused an audible joint sound.

Results

SM did not alter the erector spinae MEP amplitude in patients with LBP (0.80 ± 0.33 vs. 0.80 ± 0.30 μV) or in asymptomatic controls (0.56 ± 0.09 vs. 0.57 ± 0.06 μV). Similarly, SM did not alter the erector spinae stretch reflex amplitude in patients with LBP (0.66 ± 0.12 vs. 0.66 ± 0.15 μV) or in asymptomatic controls (0.60 ± 0.09 vs. 0.55 ± 0.08 μV). Interestingly, study participants exhibiting an audible response exhibited a 20% decrease in the stretch reflex (p < 0.05).

Conclusions

These findings suggest that a single SM treatment does not systematically alter corticospinal or stretch reflex excitability of the erector spinae muscles (when assessed ~ 10-minutes following SM); however, they do indicate that the stretch reflex is attenuated when SM causes an audible response. This finding provides insight into the mechanisms of SM, and suggests that SM that produces an audible response may mechanistically act to decrease the sensitivity of the muscle spindles and/or the various segmental sites of the Ia reflex pathway.

Osteopathic Medicine and Primary Care: one journal, two audiences

Osteopathic Medicine and Primary Care (OMPC) enters its fourth year of operation in 2010 under the umbrella of BioMed Central. Osteopathic Medicine and Primary Care strives to promote and advance research and scholarly work within the fields of osteopathic medicine and primary care. In so doing, OMPC welcomes submissions from clinicians within both the osteopathic and allopathic medical professions, and from other professionals having interests in primary care, including health care delivery, public health, and evidence-based medicine. Osteopathic Medicine and Primary Care offers fair and expeditious peer review (mean time from submission to publication, 118 days), retention of copyright for authors, unlimited online distribution and access without charge to readers, indexing in PubMed, and archiving in PubMed Central. In 2010, there will be an increased availability of waivers or discounts of article processing charges via several mechanisms for eligible authors who submit qualified manuscripts, especially in the field of primary care.