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Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery
Commentary on `Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery¿
Brian Clark, Ohio University
31 May 2011
Commentary on `Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery¿
Brian C. Clark,1,2 Stevan Walkowski,1,3 David C. Eland1,3 and John N. Howell1,2
1Ohio Musculoskeletal and Neurological Institute (OMNI), 2Department of Biomedical Sciences, and 3Department of Family Medicine
Jensen et al., in a paper entitled `Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery,¿ investigated whether two magnetic resonance imaging (MRI) approaches resulted in differences in: 1) duration of treatment, 2) number of contacts with clinicians, and 3) referral for surgery. Specifically, the authors performed a retrospective analysis by taking advantage of recent policy changes in Denmark¿s health care system whereby many patients now receive an up-front routine MRI examination during their first clinic visit. The authors found that routinely performing an up-front MRI reduced the duration of treatment and the number of contacts with clinicians, and did not increase the rate of referral for back surgery or the direct financial costs.
Our particular interest in this article relates to the details of the MRI techniques utilized to examine pathology and abnormalities of low back pain. While the specific details of the MRI protocols employed in the work by Jensen and colleagues are not detailed, one must presume that these were standard musculoskeletal imaging protocols designed primarily to examine anatomical structures. In this commentary, we seek to highlight innovative advances in MRI that permit quantitative information to be derived. In particular, we discuss the potential utility of muscle functional MRI (mfMRI) in understanding the pathology of low back pain, which may help define optimal treatment strategies.
mfMRI allows non-invasive measurement of the metabolic and hemodynamic responses of skeletal muscle by observing changes in the contrast properties of certain magnetic resonance images that occur in skeletal muscle with activity [2-4]. In brief, muscle activity causes an increase in skeletal muscle proton transverse relaxation times (increased T2), with T2 changes within a muscle being sensitive to as few as two repetitions of resistance exercise [5]. While the physiological underpinnings of these changes are complex, they primarily result from increased rates of cellular energy metabolism, which alter the image contrast properties by increasing the water content and by decreasing the intracellular pH [2]. Fleckenstein and colleagues first reported in vivo imaging of muscle activation in 1988 when they demonstrated that active and inactive muscles could be clearly distinguished following exercise and that the activity-induced increase in signal intensity correlated with exertion [6]. However, more than two decades later, the clinical utility of mfMRI has only recently begun to be explored. For example, we have previously utilized mfMRI to study the spatial pattern of muscle activation in stroke patients with spasticity [7], and others have investigated the potential use of mfMRI in assessing cervical flexor activity in whiplash-associated disorders [8], as well as to identify damaged muscles from which enzymes are being released [9].
Perhaps most pertinent to chiropractors and osteopathic physicians is our most recent work using mfMRI to quantify and localize muscle activation abnormalities in patients with sub-acute low back pain, and to use mfMRI to assess the physiologic effects of manual therapies in treating low back pain [10]. In this study we observed muscle activity asymmetries (side-to-side T2 differences) in the lumbar extensor muscles (e.g., quadratus lumborum) in patients with low back pain in comparison to asymptomatic, healthy control subjects. Furthermore, we observed that a combination of osteopathic manipulative treatments functioned to reduce these muscle activation asymmetries. This work demonstrates the feasibility of mfMRI for quantification and localization of muscle abnormalities in patients with low back pain, specifically patients with sub-acute pain. These findings, and the potential use of mfMRI in the study of acute/sub-acute/chronic back pain, are particularly intriguing when considered in the context of one commonly touted model of the low back pain that involves muscle hyperactivity: the pain-spasm-pain model [11].
In summary, innovative advances in MRI, particularly mfMRI, over the past several decades now permit more sophisticated and quantitative information to be derived from MRI images. This information may help define optimal treatment strategies by providing information about underlying muscle pathology. The findings of Jensen et al. should be interpreted in light of the type of imaging performed in their retrospective study [1], and future work should explore the clinical utility of sophisticated imaging protocols such as muscle mfMRI.
REFERENCES
1. Jensen, RK, Claus M, and Leboeuf-Yde C. Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery. Chiropr Osteopat 2010, 18:19.
2. Damon, BM, Louie EA, and Sanchez OA. Physiological basis of muscle functional MRI. J Gravit Physiol 2007, 14(1): P85-8.
3. Meyer, RA and Prior BM. Functional magnetic resonance imaging of muscle. Exerc Sport Sci Rev 2000; 28(2): 89-92.
4. Patten, C, Meyer RA, and Fleckenstein JL. T2 mapping of muscle. Semin Musculoskelet Radiol 2003, 7(4): 297-305.
5. Yue, G, Alexander AL, Laidlaw DH, Gmitro AF, Unger EC, and Enoka RM. Sensitivity of muscle proton spin-spin relaxation time as an index of muscle activation. J Appl Physiol 1994, 77(1): 84-92.
6. Fleckenstein, JL, Canby RC, Parkey RW, and Peshock RM. Acute effects of exercise on MR imaging of skeletal muscle in normal volunteers. AJR Am J Roentgenol 1988, 151(2): 231-7.
7. Ploutz-Snyder, LL, Clark BC, Logan L, and Turk M. Evaluation of spastic muscle in stroke survivors using magnetic resonance imaging and resistance to passive motion. Arch Phys Med Rehabil 2006, 87(12): 1636-42.
8. Cagnie, B, Dolphens M, Peeters I, Achten E, Cambier D, and Danneels L. Use of muscle functional magnetic resonance imaging to compare cervical flexor activity between patients with whiplash-associated disorders and people who are healthy. Phys Ther 2010, 90(8): 1157-64.
9. Larsen, RG, Ringgaard S, and Overgaard K. Localization and quantification of muscle damage by magnetic resonance imaging following step exercise in young women. Scand J Med Sci Sports 2007, 17(1): 76-83.
10. Clark, BC, Walkowski S, Conatser RR, Eland DC, and Howell JN. 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. Osteopath Med Prim Care 2009, 3:7.
11. van Dieen, JH, Selen LP, and Cholewicki J. Trunk muscle activation in low-back pain patients, an analysis of the literature. J Electromyogr Kinesiol 2003, 13(4): 333-51.
Chiropractic & Manual Therapies
Commentary on `Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery¿
31 May 2011
Commentary on `Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery¿
Brian C. Clark,1,2 Stevan Walkowski,1,3 David C. Eland1,3 and John N. Howell1,2
1Ohio Musculoskeletal and Neurological Institute (OMNI), 2Department of Biomedical Sciences, and 3Department of Family Medicine
Jensen et al., in a paper entitled `Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery,¿ investigated whether two magnetic resonance imaging (MRI) approaches resulted in differences in: 1) duration of treatment, 2) number of contacts with clinicians, and 3) referral for surgery. Specifically, the authors performed a retrospective analysis by taking advantage of recent policy changes in Denmark¿s health care system whereby many patients now receive an up-front routine MRI examination during their first clinic visit. The authors found that routinely performing an up-front MRI reduced the duration of treatment and the number of contacts with clinicians, and did not increase the rate of referral for back surgery or the direct financial costs.
Our particular interest in this article relates to the details of the MRI techniques utilized to examine pathology and abnormalities of low back pain. While the specific details of the MRI protocols employed in the work by Jensen and colleagues are not detailed, one must presume that these were standard musculoskeletal imaging protocols designed primarily to examine anatomical structures. In this commentary, we seek to highlight innovative advances in MRI that permit quantitative information to be derived. In particular, we discuss the potential utility of muscle functional MRI (mfMRI) in understanding the pathology of low back pain, which may help define optimal treatment strategies.
mfMRI allows non-invasive measurement of the metabolic and hemodynamic responses of skeletal muscle by observing changes in the contrast properties of certain magnetic resonance images that occur in skeletal muscle with activity [2-4]. In brief, muscle activity causes an increase in skeletal muscle proton transverse relaxation times (increased T2), with T2 changes within a muscle being sensitive to as few as two repetitions of resistance exercise [5]. While the physiological underpinnings of these changes are complex, they primarily result from increased rates of cellular energy metabolism, which alter the image contrast properties by increasing the water content and by decreasing the intracellular pH [2]. Fleckenstein and colleagues first reported in vivo imaging of muscle activation in 1988 when they demonstrated that active and inactive muscles could be clearly distinguished following exercise and that the activity-induced increase in signal intensity correlated with exertion [6]. However, more than two decades later, the clinical utility of mfMRI has only recently begun to be explored. For example, we have previously utilized mfMRI to study the spatial pattern of muscle activation in stroke patients with spasticity [7], and others have investigated the potential use of mfMRI in assessing cervical flexor activity in whiplash-associated disorders [8], as well as to identify damaged muscles from which enzymes are being released [9].
Perhaps most pertinent to chiropractors and osteopathic physicians is our most recent work using mfMRI to quantify and localize muscle activation abnormalities in patients with sub-acute low back pain, and to use mfMRI to assess the physiologic effects of manual therapies in treating low back pain [10]. In this study we observed muscle activity asymmetries (side-to-side T2 differences) in the lumbar extensor muscles (e.g., quadratus lumborum) in patients with low back pain in comparison to asymptomatic, healthy control subjects. Furthermore, we observed that a combination of osteopathic manipulative treatments functioned to reduce these muscle activation asymmetries. This work demonstrates the feasibility of mfMRI for quantification and localization of muscle abnormalities in patients with low back pain, specifically patients with sub-acute pain. These findings, and the potential use of mfMRI in the study of acute/sub-acute/chronic back pain, are particularly intriguing when considered in the context of one commonly touted model of the low back pain that involves muscle hyperactivity: the pain-spasm-pain model [11].
In summary, innovative advances in MRI, particularly mfMRI, over the past several decades now permit more sophisticated and quantitative information to be derived from MRI images. This information may help define optimal treatment strategies by providing information about underlying muscle pathology. The findings of Jensen et al. should be interpreted in light of the type of imaging performed in their retrospective study [1], and future work should explore the clinical utility of sophisticated imaging protocols such as muscle mfMRI.
REFERENCES
1. Jensen, RK, Claus M, and Leboeuf-Yde C. Routine versus needs-based MRI in patients with prolonged low back pain: a comparison of duration of treatment, number of clinical contacts and referrals to surgery. Chiropr Osteopat 2010, 18:19.
2. Damon, BM, Louie EA, and Sanchez OA. Physiological basis of muscle functional MRI. J Gravit Physiol 2007, 14(1): P85-8.
3. Meyer, RA and Prior BM. Functional magnetic resonance imaging of muscle. Exerc Sport Sci Rev 2000; 28(2): 89-92.
4. Patten, C, Meyer RA, and Fleckenstein JL. T2 mapping of muscle. Semin Musculoskelet Radiol 2003, 7(4): 297-305.
5. Yue, G, Alexander AL, Laidlaw DH, Gmitro AF, Unger EC, and Enoka RM. Sensitivity of muscle proton spin-spin relaxation time as an index of muscle activation. J Appl Physiol 1994, 77(1): 84-92.
6. Fleckenstein, JL, Canby RC, Parkey RW, and Peshock RM. Acute effects of exercise on MR imaging of skeletal muscle in normal volunteers. AJR Am J Roentgenol 1988, 151(2): 231-7.
7. Ploutz-Snyder, LL, Clark BC, Logan L, and Turk M. Evaluation of spastic muscle in stroke survivors using magnetic resonance imaging and resistance to passive motion. Arch Phys Med Rehabil 2006, 87(12): 1636-42.
8. Cagnie, B, Dolphens M, Peeters I, Achten E, Cambier D, and Danneels L. Use of muscle functional magnetic resonance imaging to compare cervical flexor activity between patients with whiplash-associated disorders and people who are healthy. Phys Ther 2010, 90(8): 1157-64.
9. Larsen, RG, Ringgaard S, and Overgaard K. Localization and quantification of muscle damage by magnetic resonance imaging following step exercise in young women. Scand J Med Sci Sports 2007, 17(1): 76-83.
10. Clark, BC, Walkowski S, Conatser RR, Eland DC, and Howell JN. 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. Osteopath Med Prim Care 2009, 3:7.
11. van Dieen, JH, Selen LP, and Cholewicki J. Trunk muscle activation in low-back pain patients, an analysis of the literature. J Electromyogr Kinesiol 2003, 13(4): 333-51.
Competing interests
No competing interests.