The change in the diffusion of water in normal and degenerative lumbar intervertebral discs following joint mobilization compared to prone lying

Manual therapy plus sexual advice compared with manual therapy or exercise therapy alone for lumbar radiculopathy: a randomized controlled trial

CONTEXT

The biopsychosocial approach to managing low back pain (LBP) has the potential to improve the quality of care for patients. However, LBP trials that have utilized the biopsychosocial approach to treatment have largely neglected sexual activity, which is an important social component of individuals with LBP.

OBJECTIVES

The objectives of the study are to determine the effects of manual therapy plus sexual advice (MT+SA) compared with manual therapy (MT) or exercise therapy (ET) alone in the management of individuals with lumbar disc herniation with radiculopathy (DHR) and to determine the best sexual positions for these individuals.

METHODS

This was a single-blind randomized controlled trial. Fifty-four participants diagnosed as having chronic DHR (>3 months) were randomly allocated into three groups with 18 participants each in the MT+SA, MT and ET groups. The participants in the MT+SA group received manual therapy (including Dowling's progressive inhibition of neuromuscular structures and Mulligan's spinal mobilization with leg movement) plus sexual advice, those in the MT group received manual therapy only and those in the ET group received exercise therapy only. Each group received treatment for 12 weeks and then followed up for additional 40 weeks. The primary outcomes were pain, activity limitation, sexual disability and kinesiophobia at 12 weeks post-randomization.

RESULTS

The MT+SA group improved significantly better than the MT or ET group in all outcomes (except for nerve function), and at all timelines (6, 12, 26, and 52 weeks post-randomization). These improvements were also clinically meaningful for back pain, leg pain, medication intake, and functional mobility at 6 and 12 weeks post-randomization and for sexual disability, activity limitation, pain catastrophizing, and kinesiophobia at 6, 12, 26, and 52 weeks post-randomization (p<0.05). On the other hand, many preferred sexual positions for individuals with DHR emerged, with "side-lying" being the most practiced sexual position and "standing" being the least practiced sexual position by females. While "lying supine" was the most practiced sexual position and "sitting on a chair" was the least practiced sexual position by males.

CONCLUSIONS

This study found that individuals with DHR demonstrated better improvements in all outcomes when treated with MT+SA than when treated with MT or ET alone. These improvements were also clinically meaningful for sexual disability, activity limitation, pain catastrophizing, and kinesiophobia at long-term follow-up. There is also no one-size-fits-all to sexual positioning for individuals with DHR.

Applications of Diffusion-Weighted MRI to the Musculoskeletal System

Diffusion-weighted imaging (DWI) is an established MRI technique that can investigate tissue microstructure at the scale of a few micrometers. Musculoskeletal tissues typically have a highly ordered structure to fulfill their functions and therefore represent an optimal application of DWI. Even more since disruption of tissue organization affects its biomechanical properties and may indicate irreversible damage. The application of DWI to the musculoskeletal system faces application-specific challenges on data acquisition including susceptibility effects, the low T2 relaxation time of most musculoskeletal tissues (2-70 msec) and the need for sub-millimetric resolution. Thus, musculoskeletal applications have been an area of development of new DWI methods. In this review, we provide an overview of the technical aspects of DWI acquisition including diffusion-weighting, MRI pulse sequences and different diffusion regimes to study tissue microstructure. For each tissue type (growth plate, articular cartilage, muscle, bone marrow, intervertebral discs, ligaments, tendons, menisci, and synovium), the rationale for the use of DWI and clinical studies in support of its use as a biomarker are presented. The review describes studies showing that DTI of the growth plate has predictive value for child growth and that DTI of articular cartilage has potential to predict the radiographic progression of joint damage in early stages of osteoarthritis. DTI has been used extensively in skeletal muscle where it has shown potential to detect microstructural and functional changes in a wide range of muscle pathologies. DWI of bone marrow showed to be a valuable tool for the diagnosis of benign and malignant acute vertebral fractures and bone metastases. DTI and diffusion kurtosis have been investigated as markers of early intervertebral disc degeneration and lower back pain. Finally, promising new applications of DTI to anterior cruciate ligament grafts and synovium are presented. The review ends with an overview of the use of DWI in clinical routine. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 3.

Effects of spinal manipulation or mobilization as an adjunct to neurodynamic mobilization for lumbar disc herniation with radiculopathy: a randomized clinical trial

OBJECTIVES

To determine the long-term clinical effects of spinal manipulative therapy (SMT) or mobilization (MOB) as an adjunct to neurodynamic mobilization (NM) in the management of individuals with Lumbar Disc Herniation with Radiculopathy (DHR).

DESIGN

Parallel group, single-blind randomized clinical trial.

SETTING

The study was conducted in a governmental tertiary hospital.

PARTICIPANTS

Forty (40) participants diagnosed as having a chronic DHR (≥3 months) were randomly allocated into two groups with 20 participants each in the SMT and MOB groups.

INTERVENTIONS

Participants in the SMT group received high-velocity, low-amplitude manipulation, while those in the MOB group received Mulligans' spinal mobilization with leg movement. Each treatment group also received NM as a co-intervention, administered immediately after the SMT and MOB treatment sessions. Each group received treatment twice a week for 12 weeks.

OUTCOME MEASURES

The following outcomes were measured at baseline, 6, 12, 26, and 52 weeks post-randomization; back pain, leg pain, activity limitation, sciatica bothersomeness, sciatica frequency, functional mobility, quality of life, and global effect. The primary outcomes were pain and activity limitation at 12 weeks post-randomization.

RESULTS

The results indicate that the MOB group improved significantly better than the SMT group in all outcomes (p < 0.05), and at all timelines (6, 12, 26, and 52 weeks post-randomization), except for sensory deficit at 52 weeks, and reflex and motor deficits at 12 and 52 weeks. These improvements were also clinically meaningful for neurodynamic testing and sensory deficits at 12 weeks, back pain intensity at 6 weeks, and for activity limitation, functional mobility, and quality of life outcomes at 6, 12, 26, and 52 weeks of follow-ups. The risk of being improved at 12 weeks post-randomization was 40% lower (RR = 0.6, CI = 0.4 to 0.9, p = 0.007) in the SMT group compared to the MOB group.

CONCLUSION

This study found that individuals with DHR demonstrated better improvements when treated with MOB plus NM than when treated with SMT plus NM. These improvements were also clinically meaningful for activity limitation, functional mobility, and quality of life outcomes at long-term follow-up.

TRIAL REGISTRATION

Pan-African Clinical Trial Registry: PACTR201812840142310.

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.

Intervertebral disc degeneration and regeneration: a motion segment perspective

Back and neck pain have become primary reasons for disability and healthcare spending globally. While the causes of back pain are multifactorial, intervertebral disc degeneration is frequently cited as a primary source of pain. The annulus fibrosus (AF) and nucleus pulposus (NP) subcomponents of the disc are common targets for regenerative therapeutics. However, disc degeneration is also associated with degenerative changes to adjacent spinal tissues, and successful regenerative therapies will likely need to consider and address the pathology of adjacent spinal structures beyond solely the disc subcomponents. This review summarises the current state of knowledge in the field regarding associations between back pain, disc degeneration, and degeneration of the cartilaginous and bony endplates, the AF-vertebral body interface, the facet joints and spinal muscles, in addition to a discussion of regenerative strategies for treating pain and degeneration from a whole motion segment perspective.

Assessing the contribution of lower limb mobilization, in the supine position, on shoulder-pelvis girdles dissociation

BACKGROUND

Several articular, muscular and neurological diseases generate mobility loss in the shoulder and pelvis girdles. Joint mobilization contributes to improving shoulder-pelvis girdles dissociation, but current mobilization techniques are not always successful and standardized. A robotic medical device, DPA Med®, by inducing trunk mobilization through lower limb oscillation has been developed for producing such a shoulder-pelvis girdles dissociation and is already used worldwide in rehabilitation hospitals.

RESEARCH QUESTION

To determine the optimal lower limb oscillation frequency that generated the best shoulder-pelvis girdles dissociation using the DPA Med® device.

METHODS

Thirty healthy adult volunteers (mean age: 38.6 [SD 15.2] years, mean height: 174 [SD 11.9] cm, mean body mass: 70.3 [SD 14.7] kg) participated in this prospective study. A kinematic analysis quantified pelvic and shoulder girdle mobility (rotation and lateral tilt) at different DPA Med® frequencies, from 0.5 Hz to 1 Hz. A visual analysis of the lower limb movement was also performed, using video sensors, to better understand the kinematics involved.

RESULTS

All DPA Med® frequencies have shown significant shoulder-pelvis girdles dissociation (p < 0.05). This study established an optimal oscillation frequency with the minimal interindividual variability at 0.808 Hz. It induced pelvic mobility similar to that of normal gait, in the transverse and frontal planes (10.3°, SD 2.9°, and 12.0°, SD 2.2°, respectively). This trunk mobility was achieved by producing a lemniscate-shaped motion in the lower limbs (an eight-shaped motion in the transverse plane).

SIGNIFICANCE

This study has shown that the DPA Med® device is able to induce shoulder-pelvis girdles dissociation similar to that of normal gait and allowed to establish the existence of an optimal DPA Med® oscillation frequency for lower limb mobility at 0.808 Hz. Further studies are required to evaluate its potentially benefits on gait disorders.

Two manual therapy techniques for management of lumbar radiculopathy: a randomized clinical trial

CONTEXT

Evidence has shown that spinal mobilization with leg movement (SMWLM) and progressive inhibition of neuromuscular structures (PINS) are individually effective in the management of lumbar radiculopathy. However, previous evidence reported data for only a short-term study period and did not investigate the effect of the combined manual therapy techniques.

OBJECTIVES

To compare the combined effects of two manual therapy techniques (SMWLM and PINS) with the individual techniques alone (SMWLM or PINS) in the management of individuals with lumbar radiculopathy.

METHODS

A total of 60 patients diagnosed with unilateral lumbar radiculopathy secondary to disc herniation were randomly allocated into three groups: 20 participants each in the SMWLM, PINS, and combined SMWLM + PINS groups. Each group attended two treatments per week for 30 min each, for three months. Participants were assessed at baseline, immediately posttreatment, and then at three, six, and nine months follow-up using the Visual Analog Scale (VAS), Rolland-Morris Disability Questionnaire (RMDQ), and Sciatica Bothersomeness Index (SBI).

RESULTS

Between-groups analyses using a two-way repeated-measures analysis of variance indicated significant interactions between groups and follow-up times for all outcomes (p=0.001). Participants receiving combined SMWLM + PINS treatment experienced greater improvement in leg pain, back pain, disability, and sciatica at all timelines (immediately posttreatment, and three, six, and nine months follow-up) than the participants receiving SMWLM or PINS alone (p<0.05). However, participants receiving SMWLM alone showed better improvement than the participants receiving PINS alone at all timelines (p<0.05).

CONCLUSIONS

A combined SMWLM + PINS treatment protocol showed greater improvement than the individual techniques alone in the management of individuals with LR in this study.

The degenerative lumbar disc: not a disease, but still an important consideration for OMPT practice: a review of the history and science of discogenic instability

BACKGROUND

A recent AAOMPT position paper was published that opposed the use of the term 'degenerative disc disease' (DDD), in large part because it appears to be a common age-related finding. While common, there are significant physiologic and biomechanical changes that occur as a result of discogenic degeneration, which are relevant to consider during the practice of manual therapy.

METHODS

A narrative review provides an overview of these considerations, including a historical perspective of discogenic instability, the role of the disc as a pain generator, the basic science of a combined biomechanical and physiologic cycle of degeneration and subsequent discogenic instability, the influence of rotation on the degenerative segment, the implications of these factors for manual therapy practice, and a perspective on an evidence-based treatment approach to patients with concurrent low back pain and discogenic degeneration.

CONCLUSIONS

As we consider the role of imaging findings such as DDD, we pose the following question: Do our manual interventions reflect the scientifically proven biomechanical aspects of DDD, or have we chosen to ignore the helpful science as we discard the harmful diagnostic label?

An in vivo study exploring correlations between early-to-moderate disc degeneration and flexion mobility in the lumbar spine

PURPOSE

Early disc degeneration (DD) has been thought to be associated with loss of spine stability. However, before this can be understood in relation to back pain, it is necessary to know the relationship between DD and intervertebral motion in people without pain. This study aimed to find out if early-to-moderate DD is associated with intervertebral motion in people without back pain.

METHODS

Ten pain-free adults, aged 51-71, received recumbent and weight bearing MRI scans and quantitative fluoroscopy (QF) screenings during recumbent and upright lumbar flexion. Forty individual level and 10 composite (L2-S1) radiographic and MRI DD gradings were recorded and correlated with intervertebral flexion ROM, translation, laxity and motion sharing inequality and variability for both positions.

RESULTS

Kinematic values were similar to previous control studies. DD was evidenced up to moderate levels by both radiographic and MRI grading. Disc height loss correlated slightly, but negatively with flexion during weight bearing flexion (R =  - 0.356, p = 0.0.025). Composite MRI DD and T2 signal loss evidenced similar relationships (R =  - 0.305, R =  - 0.267) but did not reach statistical significance (p = 0.056, p = 0.096). No significant relationships between any other kinematic variables and DD were found.

CONCLUSION

This study found only small, indefinite associations between early-to-moderate DD and intervertebral motion in healthy controls. Motion sharing in the absence of pain was also not related to early DD, consistent with previous control studies. Further research is needed to investigate these relationships in patients.

Long-term running in middle-aged men and intervertebral disc health, a cross-sectional pilot study

Purpose

To measure intervertebral disc (IVD) health parameters in middle-aged long-term runners compared to matched non-physically active controls.

Methods

Seventeen males aged 44-62yr were included in the study: 9 runners with a running history of >10yr, averaging >50km/week, and eight matched non-physically active controls, the data from one participant had to be excluded. T2-relaxometry, diffusion weighted imaging, T1- and T2-weighted MR scanning, as well as T2 time mapping were performed. Morphological data relating to IVD were extrapolated.

Results

Compared to controls on average, runners had 20% greater IVD height (p = 0.002) and seven percentage points greater IVD-vertebral body height ratio (p = 0.001). No significant differences were observed between groups for mean(SD) IVD hydration status, as indicated by similar T2-times (runners: 94.4(11.1)ms, controls: 88.6(23.6)ms), or apparent diffusion coefficients (runners: 249.0(175.2)mm²/s, controls: 202.3(149.5)mm²/s). Average Pfirrmann score for the L5-S1 IVD was 2.2(0.7) for runners and 3.3(1.0) for controls (p = 0.026), average scores for all lumbar levels (L2-S1) were 1.9(0.2) and 2.5(0.7), respectively (p = 0.036). Anterior annulus T2-time and overall average lumbar level Pfirrmann grades were strongly correlated (r = 0.787, p = 0.021 and r = -0.704, p = 0.034, respectively) with greater distances run per week. Average lumbar level Pfirrmann grades were also strongly correlated (r = -0.823, p = 0.006) to total years of running.

Conclusion

Middle-aged long-term endurance runners exhibit less age-related decline in their lumbar IVDs. In addition, the measures of IVD morphology appeared to be better in those who had been running for a greater number of years, as well as in those who ran a greater distance per week.

Changes in Spinal Height After Manual Axial Traction or Side Lying: A Clinical Measure of Intervertebral Disc Hydration Using Stadiometry

OBJECTIVES

The purpose of this study was to determine the immediate effects of a manual therapy technique consisting of axial traction compared with side lying on increased spine height after sustained loading.

METHODS

Twenty-one asymptomatic participants were included. Participants either received manual therapy technique consisting of manual axial traction force for 2 consecutive rounds of 3 minutes or sustained side lying for 10 minutes. Spine height was measured using a commercially available stadiometer. Spinal height change was determined from measurements taken after loaded walking and measurements taken after manual therapy. A paired t test was performed to determine if a manual therapy technique consisting of axial traction increased spinal height after a period of spinal loading.

RESULTS

A significant increase in height was found after both manual therapy technique and sustained side lying (P < .0001). The mean height gain was 8.60 mm using 3-dimensional axial separation.

CONCLUSION

This study is an initial attempt at evaluating the biomechanical effects of manual therapy technique consisting of axial traction. Both manual axial traction force and sustained side-lying position were equally effective for short-term change in spine height after a loaded walking protocol among healthy asymptomatic individuals. This study protocol may help to inform future studies that evaluate spine height after loading.

Short-term increase in discs' apparent diffusion is associated with pain and mobility improvements after spinal mobilization for low back pain

Pain perception, trunk mobility and apparent diffusion coefficient (ADC) within all lumbar intervertebral discs (IVDs) were collected before and shortly after posterior-to-anterior (PA) mobilizations in 16 adults with acute low back pain. Using a pragmatic approach, a trained orthopaedic manual physical therapist applied PA mobilizations to the participants' spine, in accordance with his examination findings. ADC _all was computed from diffusion maps as the mean of anterior (ADC _ant ), middle (ADC _mid ), and posterior (ADC _post ) portions of the IVD. After mobilization, pain ratings and trunk mobility were significantly improved and a significant increase in ADC _all values was observed. The greatest ADC _all changes were observed at the L₃-L₄ and L₄-L₅ levels and were mainly explained by changes in ADC _ant and ADC _post , respectively. No significant changes in ADC were observed at L₅-S₁ level. The reduction in pain and largest changes in ADC observed at the periphery of the hyperintense IVD region suggest that increased peripheral random motion of water molecules is implicated in the IVD nociceptive response modulation. Additionally, ADC changes were observed at remote IVD anatomical levels that did not coincide with the PA spinal mobilization application level.

MRI evaluation of the effects of extension exercises on the disc fluid content and location of the centroid of the fluid distribution

BACKGROUND

McKenzie prone press-up exercises have been hypothesised to reduce intradiscal pressure, allowing fluid to be reabsorbed into the disc, which could improve the internal stability and local chemical milieu of the disc, potentially reducing symptoms.

OBJECTIVE

To investigate the immediate effects of prone press-up exercises on lumbar disc fluid content and movement.

DESIGN

Quantification of MRI changes before and after a single exercise session.

METHODS

The mid-sagittal T₂-weighted MR images of 22 volunteers with low back pain were obtained before and immediately after performing press-up exercises. The whole disc and nucleus regions of the L4-5 and L5-S1 discs were then segmented, and their mean signal intensity (MSI) and signal intensity weighted centroid (SIWC) were computed to estimate disc fluid content and displacement.

RESULTS

There were no significant differences between the MSI and the vertical position of the SIWC of the whole disc before and after extension at either disc level (effect size [ES]: -0.23 to 0.09). There was a significant anterior displacement (0.1 ± 5.4 mm) of the location of the SIWC of the disc after extension exercise at L4-5 (ES: 0.22), but not at L5-S1 (ES: 0.00) or at either level for the nucleus region (ES: -0.06; 0.16).

CONCLUSION

Little evidence was found supporting the hypothesis that press-up exercises affect disc fluid content and distribution. Novel parameters reflecting fluid distribution detected similar or larger effects of the extension than MSI. If such exercises are effective in reducing symptoms, it is likely through other mechanisms than by changing fluid content or distribution.

Age-related differences in the response of the L5-S1 intervertebral disc to spinal traction

BACKGROUND

Lumbar traction is a common treatment for low back pain; however its mechanisms of action are poorly understood. It has been hypothesized that a key effect of lumbar traction is its capacity to influence fluid movement within the intervertebral disc (IVD).

OBJECTIVES

To determine differences in the apparent diffusion coefficient (ADC) obtained with lumbar diffusion-weighted imaging (DWI) of the L5-S1 IVD before, and during, the application of lumbar traction.

DESIGN

Case series, repeated measures.

METHODS

A static traction load of ∼50% of body-weight was applied to the low back using a novel "MRI-safe" apparatus. DWI of the lumbar spine was performed prior to, and during the application of the traction load.

RESULTS

Participants were currently asymptomatic and included a young adult group (n = 18) and a middle-aged group (n = 15). The young adult group had a non-significant 2.2% increase in ADC (mean change = 0.03 × 10^-3 mm²/s, SD = 0.24, 95% CI = -0.09, 0.15). The ADC for the middle-aged group significantly increased by 20% (mean change of 0.18 × 10^-3 mm²/s, SD = 0.19; 95% CI = 0.07, 0.28; p = 0.003; effect size = 0.95). There was an inverse relationship between the ADC obtained before traction and the percent increase in ADC that was measured during traction.

CONCLUSION

Static traction was associated with an increase in diffusion of water within the L5-S1 IVDs of middle-age individuals, but not in young adults, suggesting age-related differences in the diffusion response. Further study is needed to assess the relationship between these findings and the symptoms of back pain.

LEVEL OF EVIDENCE

4.

Physiological effects of physical therapy interventions on lumbar intervertebral discs: A systematic review

BACKGROUND CONTEXT

The use of physical therapy has been recommended in the treatment of low back pain based on primarily mechanical and neurophysiological effects. Recent studies have measured the physiological effects of physical therapy interventions, including manual therapy and traction, on the intervertebral discs (IVD), and these findings may have implications for the long-term management or even prevention of low back pain.

PURPOSE

The objective of this systematic review is to investigate the literature regarding possible physiological effects of physical therapy interventions on the intervertebral disc (IVD).

STUDY DESIGN

Systematic Review.

METHODS

A literature search of published articles through December 2014 resulted in the retrieval of 8 clinical studies assessing the influence of physical therapy interventions on the physiology of the IVD.

RESULTS

Three studies, including two using animal models, investigated the effects of 30-minute intermittent traction on disc height. One in vivo animal study and two studies using human subjects assessed changes of disc height associated with static traction. Three studies investigated the effects of lumbar spine manipulation and mobilization on changes in water diffusion within the IVD. All studies confirmed, either directly or indirectly, that their respective intervention influenced disc physiology primarily through water flow.

CONCLUSION

Physical therapy interventions may have an effect on the physiology of the IVD, primarily through water diffusion and molecular transport, which are important for the health of the IVD.

Diffusion imaging of the vertebral bone marrow

Diffusion-weighted MRI (DWI) of the vertebral bone marrow is a clinically important tool for the characterization of bone-marrow pathologies and, in particular, for the differentiation of benign (osteoporotic) and malignant vertebral compression fractures. DWI of the vertebral bone marrow is, however, complicated by some unique MR and tissue properties of vertebral bone marrow. Due to both the spongy microstructure of the trabecular bone and the proximity of the lungs, soft tissue, or large vessels, substantial magnetic susceptibility variations occur, which severely reduce the magnetic field homogeneity as well as the transverse relaxation time T^*₂ , and thus complicate MRI in particular with echoplanar imaging (EPI) techniques. Therefore, alternative diffusion-weighting pulse sequence types such as single-shot fast-spin-echo sequences or segmented EPI techniques became important alternatives for quantitative DWI of the vertebral bone marrow. This review first describes pulse sequence types that are particularly important for DWI of the vertebral bone marrow. Then, data from 24 studies that made diffusion measurements of normal vertebral bone marrow are reviewed; summarizing all results, the apparent diffusion coefficient (ADC) of normal vertebral bone marrow is typically found to be between 0.2 and 0.6 × 10^-3  mm² /s. Finally, DWI of vertebral compression fractures is discussed. Numerous studies demonstrate significantly greater ADCs in osteoporotic fractures (typically between 1.2 and 2.0 × 10^-3  mm² /s) than in malignant fractures or lesions (typically 0.7-1.3 × 10^-3  mm² /s). Alternatively, several studies used the (qualitative) image contrast of diffusion-weighted acquisitions for differentiation of lesion etiology: a very good lesion differentiation can be achieved, particularly with diffusion-weighted steady-state free precession sequences, which depict malignant lesions as hyperintense relative to normal-appearing vertebral bone marrow, in contrast to hypointense or isointense osteoporotic lesions. Copyright © 2015 John Wiley & Sons, Ltd.

Diffusion-weighted imaging in musculoskeletal radiology-clinical applications and future directions

Diffusion-weighted imaging (DWI) is an established diagnostic tool with regards to the central nervous system (CNS) and research into its application in the musculoskeletal system has been growing. It has been shown that DWI has utility in differentiating vertebral compression fractures from malignant ones, assessing partial and complete tears of the anterior cruciate ligament (ACL), monitoring tumor response to therapy, and characterization of soft-tissue and bone tumors. DWI is however less useful in differentiating malignant vs. infectious processes. As of yet, no definitive qualitative or quantitative properties have been established due to reasons ranging from variability in acquisition protocols to overlapping imaging characteristics. Even with these limitations, DWI can still provide clinically useful information, increasing diagnostic accuracy and improving patient management when magnetic resonance imaging (MRI) findings are inconclusive. The purpose of this article is to summarize recent research into DWI applications in the musculoskeletal system.

The within-session change in low back pain intensity following spinal manipulative therapy is related to differences in diffusion of water in the intervertebral discs of the upper lumbar spine and L5-S1

STUDY DESIGN

Single-group, prospective, repeated-measures design with responder analysis.

OBJECTIVE

To determine differences in the changes in diffusion of water within the lumbar intervertebral discs between participants with low back pain who reported a within-session reduction in pain intensity following a single treatment of spinal manipulative therapy and those who did not.

BACKGROUND

There is a paucity of research that describes the physiologic events associated with analgesia following intervention for low back pain. Postintervention increases in the diffusion of water within various soft tissues of the spine may be one of many potential mechanisms linked to pain reduction.

METHODS

Nineteen adults between 20 and 45 years of age participated in this study. All participants reported low back pain of at least 2 on an 11-point (0-10) verbally administered numeric pain rating scale at the time of enrollment. Participants underwent T2- and diffusion-weighted lumbar magnetic resonance imaging scans immediately before and after receiving a single treatment of spinal manipulative therapy. Individuals who reported a decrease in current pain intensity of more than 2 following treatment were classified as "within-session responders," and the remainder were classified as "not-within-session responders." The apparent diffusion coefficient (ADC), representing the diffusion of water in the nucleus pulposus, was calculated from ADC maps derived from the midsagittal diffusion-weighted images.

RESULTS

Two-way, repeated-measures analyses of variance indicated significant group-by-time interactions. Participants in the within-session-responder group (n = 12) had a postintervention increase in ADC at L1-2 (P = .001), L2-3 (P = .002), and L5-S1 (P = .01) compared to those in the not-within-session-responder group (n = 7). Large effect sizes in ADC between responder groups were observed at L1-2 (d = 1.74), L2-3 (d = 1.83), and L5-S1 (d = 1.49). No significant group-by-time interactions were observed at the L3-4 and L4-5 levels.

CONCLUSION

Changes in the diffusion of water within the lumbar intervertebral discs at the L1-2, L2-3, and L5-S1 levels appear to be related to differences in within-session pain reports following a single treatment of spinal manipulative therapy.

Magnetic resonance imaging: the underlying principles

The creation of a magnetic resonance image (MRI) and its inherent contrast are controlled by a variety of anatomical structure- and sequence-dependent parameters. While these may seem confusing to the uninitiated, they provide MRI with great flexibility and make it a powerful clinical tool. This article describes the principles of basic physics behind magnetic resonance spectroscopy (MRS) and imaging, including a basic description of the properties of magnetic resonance compatible nuclei, how a radiofrequency (RF) pulse produces a signal, and how this signal can be spatially encoded to produce an image. The relaxation properties of the MRI signal depend on biological tissue type and can provide information on tissue composition, environment, and pathological changes. The contrast properties within an image can be manipulated based on the relaxation properties of the anatomical sample and the nature of the imaging sequence. The benefits of T1- and T2-weighted images in musculoskeletal imaging and the common sequences used (including turbo spin echo [TSE], fat suppression sequences such as STIR, and rapid breath-hold sequences such as HASTE and FISP) are discussed. The principles behind contrast agents and diffusion-weighted imaging and how they can be applied in the body are considered.

Diffusion-weighted magnetic resonance imaging of the musculoskeletal system: an emerging technology with potential to impact clinical decision making

Diffusion-weighted imaging (DWI) is an application of magnetic resonance imaging that allows the measurement of water movement within and between tissues. Originally developed as a way of detecting early signs of stroke or brain disease, DWI is now being used to study physiologic events within the musculoskeletal system. The accurate measurement of water diffusion can provide important information regarding tissue responses associated with trauma and disease, as well as offer insight toward the mechanism by which physical therapy interventions affect tissues. The purpose of this paper is to discuss the rationale for DWI and its potential clinical and research applications for patients with musculoskeletal disorders. Specific examples of the use of DWI for patients with painful spinal disorders are used as illustrations.

Healing of a painful intervertebral disc should not be confused with reversing disc degeneration: implications for physical therapies for discogenic back pain

BACKGROUND

Much is known about intervertebral disc degeneration, but little effort has been made to relate this information to the clinical problem of discogenic back pain, and how it might be treated.

METHODS

We re-interpret the scientific literature in order to provide a rationale for physical therapy treatments for discogenic back pain.

INTERPRETATION

Intervertebral discs deteriorate over many years, from the nucleus outwards, to an extent that is influenced by genetic inheritance and metabolite transport. Age-related deterioration can be accelerated by physical disruption, which leads to disc "degeneration" or prolapse. Degeneration most often affects the lower lumbar discs, which are loaded most severely, and it is often painful because nerves in the peripheral anulus or vertebral endplate can be sensitised by inflammatory-like changes arising from contact with blood or displaced nucleus pulposus. Surgically-removed human discs show an active inflammatory process proceeding from the outside-in, and animal studies confirm that effective healing occurs only in the outer anulus and endplate, where cell density and metabolite transport are greatest. Healing of the disc periphery has the potential to relieve discogenic pain, by re-establishing a physical barrier between nucleus pulposus and nerves, and reducing inflammation.

CONCLUSION

Physical therapies should aim to promote healing in the disc periphery, by stimulating cells, boosting metabolite transport, and preventing adhesions and re-injury. Such an approach has the potential to accelerate pain relief in the disc periphery, even if it fails to reverse age-related degenerative changes in the nucleus.

Diffusion-weighted magnetic resonance imaging for the healthy cervical multifidus: a potential method for studying neck muscle physiology following spinal trauma

STUDY DESIGN

Cross-sectional.

OBJECTIVE

To develop a new magnetic resonance imaging (MRI) measure for the diffusive properties of the healthy cervical multifidus and to determine the interrater and intrarater reliability of the measurement.

BACKGROUND

Diffusion-weighted MRI, via calculation of the apparent diffusion coefficient (ADC), provides a representation of microscopic movements of water molecules in human tissues and may be useful to assess structural changes in neck muscle, as has been observed following whiplash. The optimal imaging parameters, however, have not been established.

METHODS

A diffusion-weighted MRI measure was developed, and, for the basic examination, the right cervical multifidus muscle at the C5 level was studied. A total of 6 asymptomatic volunteer individuals (3 females and 3 males) underwent a single diffusion-weighted MRI scan. Interrater and intrarater agreement was evaluated using Bland-Altman plots and intraclass correlation coefficients.

RESULTS

Mean ADCb0-b50 and ADCb50-250 were significantly different from one another (P=.03). The plots confirmed the agreement of raters for ADC of the right cervical multifidus at C5.

CONCLUSIONS

A quantitative and reliable diffusion-weighted MRI measure of cervical multifidus ADC has been described. There appears to be a fast and slow component ADC for the healthy multifidus, suggesting changes in extracellular and intracellular volume. Further comparative study is needed to quantify ADCs in the neck muscles in patients with traumatic whiplash.

The immediate reduction in low back pain intensity following lumbar joint mobilization and prone press-ups is associated with increased diffusion of water in the L5-S1 intervertebral disc

STUDY DESIGN

Single-group, prospective, repeated-measures design.

OBJECTIVES

To determine differences in the changes of diffusion of water in the L5-S1 intervertebral disc between subjects with nonspecific low back pain (LBP) who reported an immediate reduction in pain intensity of 2 or greater on an 11-point (0-10) numeric rating scale after a 10-minute session of lumbar joint mobilization, followed by prone press-up exercises, compared to those who did not report an immediate reduction in pain intensity of 2 or greater on the pain scale.

BACKGROUND

Combining lumbar joint mobilization and prone press-up exercises is a common intervention for patients with LBP; however, there is conflicting evidence regarding the effectiveness and efficacy of this approach. Increased knowledge of the physiologic effects of the combined use of these treatments, and the relationship to pain reports, can lead to refinement of their clinical application.

METHODS

Twenty adults, aged 22 to 54, participated in this study. All subjects reported LBP of at least 2 on an 11-point (0-10) verbally administered numeric rating scale at the time of enrollment in the study and were classified as being candidates for the combination of joint mobilization and prone press-ups. Subjects underwent T2- and diffusion-weighted lumbar magnetic resonance imaging scans before and immediately after receiving a 10-minute session of lumbar pressures in a posterior-to-anterior direction and prone press-up exercises. Subjects who reported a decrease in current pain intensity of 2 or greater immediately following treatment were classified as immediate responders, while the remainder were classified as not-immediate responders. The apparent diffusion coefficient, representing the diffusion of water in the nucleus pulposis, was calculated from the midsagittal diffusion-weighted images.

RESULTS

Following treatment, immediate responders (n = 10) had a mean increase in the apparent diffusion coefficient in the middle portion of the L5-S1 intervertebral disc of 4.2% compared to a mean decrease of 1.6% for the not-immediate responders (P<.005).

CONCLUSION

In a group of subjects with LBP, who were classified as being candidates for extension-based treatment, the report of an immediate reduction in pain intensity of 2/10 of greater after a treatment of posterior-to-anterior-directed pressures, followed by prone press-up exercises, was associated with an increase in diffusion of water in the nuclear region of the L5-S1 intervertebral disc. Subjects who did not report a pain reduction of at least 2/10 did not have a change in diffusion. J Orthop Sports Phys Ther 2010;40(5):256-264, Epub 12 March 2010. doi:10.2519/jospt.2010.3284.