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

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.

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.

Effect of Tai Chi Chuan on degeneration of lumbar vertebrae and lumbar discs in middle-aged and aged people: a cross-sectional study based on magnetic resonance images

Objective Exercise has a positive effect on physical fitness. Tai Chi Chuan is a traditional Chinese aerobic exercise. We assessed the effect of Tai Chi on the degeneration of lumbar vertebrae and lumbar discs with magnetic resonance images. Methods This retrospective cohort study involved 2 groups of participants: 27 Tai Chi practitioners with more than 4 years of experience with regular Tai Chi exercise and 24 sex- and age-matched participants without Tai Chi experience. The lumbar magnetic resonance images of all participants were collected. The numbers of degenerated lumbar vertebrae and lumbar discs were evaluated by the same radiologist, who was blind to the grouping. Results The Tai Chi practitioners had significantly fewer degenerated lumbar vertebrae (1.9) and lumbar discs (2.3) than the control group (2.6 and 2.9, respectively). The most severely affected lumbar vertebrae and discs were L5 and L4/L5, respectively. Conclusion Regular performance of the simplified Tai Chi 24 form could possibly retard the degeneration of lumbar vertebrae and lumbar discs in middle-aged and aged people.

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.

Do participants with low back pain who respond to spinal manipulative therapy differ biomechanically from nonresponders, untreated controls or asymptomatic controls?

STUDY DESIGN

Nonrandomized controlled study.

OBJECTIVE

To determine whether patients with low back pain (LBP) who respond to spinal manipulative therapy (SMT) differ biomechanically from nonresponders, untreated controls or asymptomatic controls.

SUMMARY OF BACKGROUND DATA

Some but not all patients with LBP report improvement in function after SMT. When compared with nonresponders, studies suggest that SMT responders demonstrate significant changes in spinal stiffness, muscle contraction, and disc diffusion. Unfortunately, the significance of these observations remains uncertain given methodological differences between studies including a lack of controls.

METHODS

Participants with LBP and asymptomatic controls attended 3 sessions for 7 days. On sessions 1 and 2, participants with LBP received SMT (+LBP/+SMT, n = 32) whereas asymptomatic controls did not (-LBP/-SMT, n = 57). In these sessions, spinal stiffness and multifidus thickness ratios were obtained before and after SMT and on day 7. Apparent diffusion coefficients from lumbar discs were obtained from +LBP/+SMT participants before and after SMT on session 1 and from an LBP control group that did not receive SMT (+LBP/-SMT, n = 16). +LBP/+SMT participants were dichotomized as responders/nonresponders on the basis of self-reported disability on day 7. A repeated measures analysis of covariance was used to compare apparent diffusion coefficients among responders, nonresponders, and +LBP/-SMT subjects, as well as spinal stiffness or multifidus thickness ratio among responders, nonresponders, and -LBP/-SMT subjects.

RESULTS

After the first SMT, SMT responders displayed statistically significant decreases in spinal stiffness and increases in multifidus thickness ratio sustained for more than 7 days; these findings were not observed in other groups. Similarly, only SMT responders displayed significant post-SMT improvement in apparent diffusion coefficients.

CONCLUSION

Those reporting post-SMT improvement in disability demonstrated simultaneous changes between self-reported and objective measures of spinal function. This coherence did not exist for asymptomatic controls or no-treatment controls. These data imply that SMT impacts biomechanical characteristics within SMT responders not present in all patients with LBP. This work provides a foundation to investigate the heterogeneous nature of LBP, mechanisms underlying differential therapeutic response, and the biomechanical and imaging characteristics defining responders at baseline.

LEVEL OF EVIDENCE

3.

Focus on diffusion MR investigations of musculoskeletal tissue to improve osteoporosis diagnosis: a brief practical review

Nowadays, a huge number of papers have documented the ability of diffusion magnetic resonance imaging (D-MRI) to highlight normal and pathological conditions in a variety of cerebral, abdominal, and cardiovascular applications. To date, however, the role of D-MRI to investigate musculoskeletal tissue, specifically the cancellous bone, has not been extensively explored. In order to determine potentially useful applications of diffusion techniques in musculoskeletal investigation, D-MRI applications to detect osteoporosis disease were reviewed and further explained.

Magnetic resonance imaging: generating a new pulse in the physical therapy profession

The ability to refer for diagnostic tests is particularly relevant to the topic of this special issue on magnetic resonance imaging (MRI). As a doctoring profession, one could argue that the ability to refer a patient for MRI (and other imaging applications) must be available to the direct-access physical therapist. Though the prescription for and use of MRI has not typically been considered within the scope of physical therapist practice, this may be the perfect time to challenge the obstacles precluding the obtainment of such diagnostic privileges and to specifically provide perspective on why and how such a specialized privilege could positively impact the provision of physical therapy services and patient outcomes. An expected obligation of such autonomy, however, is accountability. Is our entire profession adequately prepared to accept the role of, or the responsibilities associated with, referral for imaging privileges?