Accepted Manuscript Multifidus muscle size in adolescents with and without back pain using ultrasonography Nahid Rahmani, PT, PhD, Assistant Professor, Ali Kiani, PT, MSc, Physiotherapist, Mohammad Ali Mohseni-Bandpei, PT, PhD, Professor,Visiting Professor, Iraj Abdollahi, PT, PhD, Associate Professor PII:
S1360-8592(17)30116-X
DOI:
10.1016/j.jbmt.2017.05.016
Reference:
YJBMT 1539
To appear in:
Journal of Bodywork & Movement Therapies
Please cite this article as: Rahmani, N., Kiani, A., Mohseni-Bandpei, M.A., Abdollahi, I., Multifidus muscle size in adolescents with and without back pain using ultrasonography, Journal of Bodywork & Movement Therapies (2017), doi: 10.1016/j.jbmt.2017.05.016. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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Multifidus muscle size in adolescents with and without back pain using Ultrasonography Authors:
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Nahid Rahmani (PT, PhD)1, Ali Kiani (PT, MSc)2, Mohammad Ali Mohseni-Bandpei (PT, PhD)3, Iraj Abdollahi (PT, PhD) 4
Assistant Professor, Pediatric Neurorehabilitation Research Center, University of Social
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1
Welfare and Rehabilitation Sciences, Tehran, Iran.
[email protected] Physiotherapist, Department of Physiotherapy, University of Social Welfare and Rehabilitation
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2
Sciences, Tehran, Iran.
[email protected] 3
Professor, Iranian Research Center on Aging, University of Social Welfare and Rehabilitation
Sciences, Tehran, Iran, AND Visiting Professor, University Institute of Physical Therapy, of
Allied
Health
Sciences,
University
of
Lahore,
Lahore,
Pakistan.
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Faculty
[email protected] 4
Associate Professor. Department of Physiotherapy, University of Social Welfare and
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Rehabilitation Sciences, Tehran, Iran.
[email protected]
Corresponding Author:
Mohammad Ali Mohseni-Bandpei (PT, PhD): “Professor, Iranian Research Center on Aging, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran, AND Visiting Professor, University Institute of Physical Therapy, Faculty of Allied Health Sciences, University of Lahore, Lahore, Pakistan”. PO Box: 1985713834, Tel: +98 21 22180137, Fax: +98 21 22180039 1
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Email:
[email protected]
Author Disclosures:
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Financial Support: The study was financially supported by the University of Social Welfare and Rehabilitation Sciences and there is no financial benefit for the authors.
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Conflict of interest: There is no conflict of interest for this study.
Previous presentations: This is to confirm that the result of the present study was not presented in
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any form elsewhere.
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Multifidus muscle size in adolescents with and without back pain using Ultrasonography
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Abstract
Objective: The purposes of this study were; a) to compare multifidus muscle cross sectional area (CSA) in male adolescents suffering from low back pain (LBP) with healthy male adolescents using ultrasonography (US), and b) to assess the correlation between multifidus muscle size and
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demographic variables.
Methods: A random sample of 40 healthy boys (as a control group) and 40 boys with LBP (as an
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experimental) at the age range of 15-18 years was recruited in the present cohort study. Multifidus muscle dimensions including CSA, antero-posterior and medio-lateral dimensions were measured at level of L5 in both groups using US.
Results: The results of an independent t-test to compare multifidus muscle size between experimental and control groups showed a significant difference between the two groups in
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terms of CSA, antro-posterior and medio-lateral dimensions so that the experimental group had smaller muscle size than the control group. A significant correlation was found between height, weight and body mass index (BMI) and multifidus muscle size, but no significant correlation was observed between age and muscle size. Pain intensity and functional disability index was
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significantly correlated with muscle size in the experimental group. Conclusions: According to the results, multifidus muscle size was decreased in 15 to 18 years
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old male adolescents suffering from LBP compared with their healthy counterparts. Further studies are needed to support the findings of the present study. Keywords: Multifidus muscle, cross sectional area, ultrasonography, adolescent, low back pain
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INTRODUCTION Low back pain (LBP) is one of the most prevalent musculo-skeletal disorders. The life time prevalence of LBP has been reported to be between 58% and 84% (Andersson 1999,
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Walker et al 2004, Rubin 2007). In many studies the prevalence of this disorder was investigated in children population (Leah et al 2007, Mohseni-Bandpei et al 2007, Masiero et al 2008). Direct and indirect costs of LBP were estimated to be about 118.8 Billion dollars in the United States (Leah et al 2007).
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In previous studies, spinal stability disorder was demonstrated to be a possible cause of LBP (Bergmark 1989). According to the Panjabi’s theory of spinal stability, active
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elements (i.e., stabilizer muscles) provide segmental stability of the spine (Panjabi 1992). Several studies also reported that lumbar multifidus is one of the main stabilizer muscles of the spine which may be changed in patients with LBP (Hides et al 1996, 2001). There is still no general consensus on the most valid and reliable method to measure the strength of deep multifidus muscle. Measuring cross-sectional area (CSA) of lumbar
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multifidus will be of value to study the capacity of its force generation and activity level indirectly (Kanehisa et al 1994, Maughan et al 1983). There are different available methods to assess muscle characteristics and morphologies including Electromyography
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(Beith et al 2001, Brown and McGill 2010, Mohseni-Bandpei et al 2014), Magnetic Resonance Imaging (MRI) (Hides et al 2006, 2007, 2010) and Sonography (Whittaker 2008, Langevin et al 2009, Ghamkhar et al 2011, Pulkovski et al 2012). Among these
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methods, sonography seems to be more applicable, reliable, valid, cheaper and more accessible than other methods (Javanshir et al 2010, Mohseni Bandpei et al 2014, Rahmani et al 2015).
According to the literature, no published study was found to investigate the multifidus muscle morphology in adolescents with LBP using sonography as all previously published studies were conducted in adult population. Therefore, the primary purpose of this study was to compare the multifidus muscle CSA in male adolescents suffering from 4
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LBP with healthy male adolescents using sonography and the secondary purpose was to
MATERIALS AND METHODS
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evaluate the correlation between multifidus muscle size and demographic variables.
The present cohort study received ethical approval from the medical ethics committee at the university of social welfare and rehabilitation sciences, Tehran, Iran. Forty healthy
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boys (as a control group) and 40 boys suffering from LBP (as an experimental group) within the age range of 15 to 18 years old participated in the present study. All subjects in
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both groups were matched in terms of their age and body mass index (BMI). The sample size was estimated based on the information received from a pilot study. According to the standard deviation of muscle size in the control group = 0.17, the standard deviation of muscle size in the experimental group = 0.15, the average of muscle size in the control group = 1.82 and the average of muscle size in the experimental group = 1.72, 40 subjects were needed for the purpose of this study. All subjects and their parents received written
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information sheet about the purpose of the study and they were then asked to sign the consent form if they were willing to participate. All boys were screened based on the inclusion and exclusion criteria of the study. The inclusion criteria were: boys with a
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good healthy condition, age from 15 to 18 years old, without any history of LBP in their life for the control group and 15 to 18 years old boys suffering from LBP at least in the last three months for the experimental group. The exclusion criteria were: any extra
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physical activity such as professional sport activities, any history of sacroiliac disorder, cardio-pulmonary
disease,
malignancies,
neurological
disorders,
fractures
and
dislocations of the spine, scoliosis, spondylolysis and spondylolisthesis, disc herniation, rheumatoid arthritis and metabolic disorders. All screening programs were performed by an experienced spine surgeon. The sonography device, model LEO-3000D1(XuZhou LEO Medical Equipment, Co., Ltd), was used in order to evaluate the multifidus muscle CSA. The curve probe with 5
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frequency of 3.5 MHz was applied to take images (Hides et al 2008). Subject was asked to lie down on the examining bed in the prone position with a pillow under abdomen, and then the examiner with five years experience of working with sonography took image
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from multifidus at the L5/S1 level. In order to identify multifidus, the line connecting two iliac crests was found and the midpoint in the lumbar spine was marked and considered as the L5/S1 level. The probe of sonography was rubbed with the ultrasonic gel and placed perpendicular on L5/S1 level. Three images of multifidus muscle were taken and
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measured. The average of these three images were calculated and used for data analysis. Pain intensity and functional disability of subjects with LBP were measured using visual analogue scale (VAS) (Carlsson 1983) and Oswestry disability questionnaire (ODQ)
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(Fairbank and Pynsent 2000), respectively. Antero-posterior (AP), medio-lateral (ML) dimension and CSA of multifidus muscle were measured and analyzed. To compare multifidus muscle size between the two groups, an independent t-test was used. Pearson correlation coefficient was also utilized to investigate the correlation between muscle size
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and other variables. Level of significance was set at 0.05.
RESULTS
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TABLE 1, HERE
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Demographic characteristics of subjects in both groups are demonstrated in Table 1.
The normality of distribution of the data was checked using Kolmogorov-Smirnov test, and all parameters had normal distribution (P > 0.05 in all instances) The results of an independent t-test to compare multifidus muscle size between healthy boys and those with LBP are demonstrated in Table 2. A significant difference was found between the two groups in terms of CSA, AP and ML dimensions. Muscle dimensions in
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all parameters including CSA, AP and ML were smaller in the experimental group than the control group. TABLE 2, HERE
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The results of correlation between demographic variables and muscle size were shown in Table 3. In both groups, a significant correlation was found between height, weight and BMI and multifidus muscle size, but no significant correlation was found between age
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and muscle size.
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TABLE 3, HERE
In Table 4, the results of correlation between pain intensity and functional disability index with multifidus muscle size were demonstrated in the experimental group. A significant correlation was found between pain intensity and functional disability index
TABLE 4, HERE
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with muscle size.
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DISCUSSION
The purpose of the present study was to compare the multifidus muscle CSA between
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healthy male adolescents and male adolescents with LBP. The results indicated hat the muscle size decreased in male adolescents with LBP compared with healthy subjects. Wallwork et al (2007) carried out a study with the aim of comparing multifidus muscle CSA and its capacity of creating voluntary isometric contraction at four vertebral levels in 34 healthy subjects and patients with LBP using sonography. The results demonstrated that the muscle size at L5 level was significantly smaller in the patients group than the healthy group. They reported that the pattern of multifidus muscle atrophy would be more localized at the specific level and there was a significant correlation between muscle atrophy and the capacity of creating voluntary isometric contraction of the muscle 7
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(Wallwork et al 2007). The results of Wallwork et al’s study were consistent with the results of Hides et al (2008). However, the morphologic changes of multifidus muscle can be considered as an indirect index for changing muscle recruitment and leading to
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motor control dysfunction associated with LBP. The results of the present study showed that there was no significant correlation between multifidus muscle size and age, but the correlation between muscle size and height, weight and BMI was demonstrated to be significant. Valentine et al (2014) investigated
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the trunk muscles volume (erector spinae, multifidus, rectus abdominis and psoas major) in two groups of adult using MRI. They reported that there was a negative correlation
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between age and multifidus muscle size. In a study carried out by Scholten et al (2003) in children (11 weeks to 16 years old), the results did not reveal any significant correlation between age and limb muscles size. The results of two above mentioned studies indicated that age may have an effect on muscle echo-intensity. The findings of the present study on correlation between age and multifidus muscle size in adolescents with the age of 15-
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18 years old were consistent with the results of previous studies. Nuzzo et al (2013) reported a significant correlation between multifidus muscle size and BMI. Valentin et al (2014) showed a significant positive correlation between trunk extensor muscles volume and BMI. The results of the present study were in agreement
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with the results of the previous studies that demonstrated a significant positive correlation between multifidus muscle size and BMI in healthy adolescents and those suffering from
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LBP. The correlation between weight and limb muscles was investigated in some studies in children. Scholten et al (2003) reported that limb muscle size was dependent to the subject’s weight. Also, Maurits et al (2004) in a study on 45 to 165 months old children, reported that weight could be the best predictor for limb muscle size. In the present study, a significant positive correlation was found between weight and multifidus muscle size in both the control and the experimental groups. According to the results of the present study, a significant correlation was identified between multifidus muscle size, pain intensity and disability index. In a study conducted 8
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by Mannion et al (2012), no significant correlation was found between pain intensity and disability index in patients with LBP, although both pain intensity and functional disability were reported to be reduced following stabilization exercises. Fortin et al
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(2013) have also investigated the correlation between paraspinal muscles morphology, pain intensity and disability level on 202 adult men using MRI and reported no significant correlation between these items. The results of the present study, with significant correlation between multifidus muscle size and pain intensity and disability
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index in adolescents, indicated that muscle size may be decreased with increasing pain
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intensity and the level of disability.
CONCLUSIONS
The present study demonstrated that the multifidus muscle size was decreased in 15 to 18 years old male adolescents suffering from LBP compared with their healthy counterparts. No significant correlation was found between age and multifidus muscle size but a
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significant correlation was identified between height, weight and BMI with muscle size. A significant correlation was also found between pain intensity, functional disability level
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and muscle size.
CLINICAL APPLICATIONS
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With additional support from further large scale studies, the results of the present study seem to be helpful for clinicians and researchers to identify adolescents with LBP based on their muscles size and then design the treatment program to train stabilizer muscles for LBP group. According to the findings of the present study, it might be possible to monitor the effectiveness of different interventional programs in adolescents with LBP.
LIMITATIONS AND RECOMMENDATIONS 9
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The main limitation for this study was difficulty to coordinate with people in charge at the Tehran education and training organization in order to get permission to enter to the high schools. Another limitation was lack of blindness for examiner in this study.
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However, future similar studies with larger sample size, in a wide age range group and also in both gender population are recommended. It is also suggested that further studies can be designed to investigate the effect of stabilization exercises on muscle size in children and adolescent population and to follow the effect of treatment program in these
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REFERENCES
SC
age groups.
Andersson GB. Epidemiological features of chronic low back pain. Lancet. 1999; 354: 581-585.
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Beith I., Synnott R and Newman S. Abdominal muscle activity during the abdominal hollowing manoeuvre in the four point kneeling and prone positions. Manual Therapy. 2001; 6(2): 82-87.
EP
Bergmark A. Stability of the lumbar spine: a study in mechanical engineering. Acta
AC C
Orthopaedica. 1989; 60(S230): 1-54.
Brown SH, and McGill SM. A comparison of ultra¬sound and electromyography measures of force and activation to examine the mechanics of abdominal wall contraction. Clinical Biomechanics. 2010; 25: 115-123.
Carlsson AM. Assessment of chronic pain. Aspects of the reliability and validity of the visual analogue scale. Pain. 1983; 16(1): 87-101.
10
ACCEPTED MANUSCRIPT
Fairbank JCT, Pynsent PB. The Oswestry Disability Index. Spine. 2000; 25(22): 2940-2953.
RI PT
Fortin M, Yuan Y, Battie MC. Factors associated with paraspinal muscle asymmetry in size and composition in a general population sample of men. Physical Therapy. 2013; 93: 1540-1550.
SC
Ghamkhar L, Emami M, Mohseni-Bandpei MA, Behtash H. Application of rehabilitative ultrasound in the assessment of low back pain: a literature review.
M AN U
Journal of Bodywork and Movement Therapies. 2011; 15: 465-477.
Hides JA, Belavy DL, Stanton WR, Wilson SJ, Rittweger J, Felsenberg D, Richardson CA. Magnetic resonance imaging assessment of trunk muscles during prolonged bed rest. Spine. 2007; 32(15): 1687-1692.
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Hides JA, Boughen CL, Stanton WR, Strudwick MW, Wilson SJ. A magnetic resonance imaging investigation of the transversus abdominis muscle during drawingin of the abdominal wall in elite Australian Football League players with and without
AC C
10.
EP
low back pain. The Journal of Orthopaedic and Sports Physical Therapy. 2010; 40: 4-
Hides JA, Gilmore C, Stanton W and Bohlscheid E. Multifidus size and symmetry among chronic LBP and healthy asymptomatic subjects. Manual Therapy. 2008; 13: 43-49.
Hides JA, Jull GA, Richardson CA. Long-term effects of specific stabilizing exercises for first-episode low back pain. Spine. 2001; 26(11): 243-248.
11
ACCEPTED MANUSCRIPT
Hides JA, Richardson CA, Jull GA. Multifidus muscle recovery is not automatic after
RI PT
resolution of acute, first-episode low back pain. Spine. 1996; 21(23): 2763-2769.
Hides JA, Stanton WR, McMahon S, Sims K, Richardson CA. Effect of stabilization training on multifidus muscle cross-sectional area among young elite cricketers with
SC
low back pain. Journal of Orthopedic Sport Physical Therapy. 2008; 38(3): 101-108.
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Hides JA, Wilson SJ, Stanton WR, McMahon S, Keto H, McMahon K, Bryant M, Richardson CA. An MRI investigation into the function of the transversus abdominis muscle during “drawing-in” of the abdominal wall. Spine. 2006; 31: 175-178.
Javanshir K, Amiri M, Mohseni-Bandpei MA, Rezasoltani A, Fernandez-de-las-Penas C. Ultrasonography of the cervical muscles: a critical review of the literature. Journal
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of Manipulative and Physiological Therapeutics. 2010; 33(8): 630-637.
Kanehisa H, Ikegawa S, Fukunaga T. Comparison of muscle cross sectional area and
EP
strength between untrained women and men. European Journal of Applied Physiology
AC C
and Occupational Physiology. 1994; 68: 148-154.
Langevin HM, Stevens-Tuttle D, Fox JR, Badger GJ, Bouffard NA, Krag MH, Wu J, Henry SM. Ultrasound evidence of altered lumbar connective tissue structure in human subjects with chronic low back pain. BMC Musculoskeletal Disorders. 2009; 10(1): 151.
Leah J, Steve F, and Karen A. Epidemiology of adolescent spinal pain: a systematic overview of the research literature. Spine. 2007; 23: 2630-2637. 12
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Mannion AF, Caporaso F, Pulkovski N, Sprott H. Spine stabilization exercises in the treatment of chronic low back pain: A good clinical outcome is not associated with
RI PT
improved abdominal muscle function. European Spine Journal. 2012; 21(7): 13011310.
Masiero S, Carraro E, Celia A, Sarto D and Ermani M. Prevalence of nonspecific low
SC
back pain in schoolchildren aged between 13 and 15 years. Acta Paediatrica. 2008;
M AN U
97(2): 212-216.
Maughan RJ, Watson JS, Weir J. Strength and cross sectional area of human skeletal muscle. The Journal of Physiology. 1983; 338: 37-49.
Maurits NM, Beenakker EAC, Schaik DEC, Fock JM, Hoeven JH. Muscle ultrasound
TE D
in children: normal values and application to neuromuscular disorders. Ultrasound in
EP
Medicine & Biology. 2004; 30: 1017-1027.
Mohseni-Bandpei MA, Bagheri-Nesami M, and Shayesteh-Azar M. Nonspecific low
AC C
back pain in 5000 Iranian school-age children. Journal of Pediatric Orthopaedics. 2007; 27(2): 126-129.
Mohseni-Bandpei MA, Rahmani N, Majdoleslam B, Abdollahi I, Shah Ali Sh, Ahmad A. Reliability of surface electromyography in the assessment of paraspinal muscle fatigue: An updated systematic review. Journal of Manipulative and Physical Therapy. 2014; 37: 510-521.
13
ACCEPTED MANUSCRIPT
Nuzzo JL, Mayer JM. Body mass normalization for ultrasound measurements of lumbar multifidus and abdominal muscle size. Manual Therapy. 2013; 18(3): 237-
RI PT
242.
Panjabi MM. The stabilizing system of the spine. Part I. Function, dysfunction, adaptation, and enhancement. Journal of Spinal Disorders and Techniques. 1992;
SC
5(4): 383-389.
Pulkovski N, Mannion AF, Caporaso F, Toma V, Gubler D, Helbling D and Sprott H.
M AN U
Ultrasound assessment of transversus abdominis muscle contraction ratio during abdominal hollowing: a useful tool to distinguish between patients with chronic low back pain and healthy controls? European Spine Journal. 2012; 21(6): 750-759.
Rahmani N, Mohseni-Bandpei MA, Vameghi R, Salavati M, Abdollahi I. Application of ultrasonography in the assessment of skeletal muscles in children with and without
2015; 41(9): 1-9.
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neuromuscular disorders: A systematic review. Ultrasound in Medicine and Biology.
AC C
353-371.
EP
Rubin DI. Epidemiology and risk factors for spine pain. Neurologic Clinics. 2007; 25:
Scholten RR, Pillen S, Verrips A, Zwarts MJ. Quantitative ultrasonography of skeletal muscles in children: normal values. Muscle and Nerve. 2003; 27: 693-698.
Valentin S, Licka T, Elliott J. Age and side-related morphometric MRI evaluation of trunk muscles in people without back pain. Manual Therapy. 2015; 20(1): 90-95.
14
ACCEPTED MANUSCRIPT
Walker BF, Muller R and Grant WD. Low back pain in Australian adults: Health provider utilization and care seeking. Journal of Manipulative and Physiological
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Therapeutics. 2004; 27: 327-335.
Wallwork TL, Stanton WR, Freke M, Hides JA. The effect of chronic low back pain
SC
on size and contraction of the lumbar multifidus muscle. Manual Therapy. 2009;
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14(5): 496-500.
Whittaker JL. Ultrasound imaging of the lateral abdominal wall muscles in individuals with lumbopelvic pain and signs of concurrent hy-pocapnia. Manual
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EP
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Therapy. 2008; 13: 404-410.
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Table1. Demographic characteristics of all subjects
Variables
Control group
Experimental group
SD
Range
Mean
SD
Range
p-value
Age (year)
16.5
1.12
15-18
16.5
1.12
15-18
-
Weight
68.41
11.89
45-98
74.50
12.33
60-95
0.92
174.78
8.51
140-190
176.60
9.88
160-190
0.35
22.76
2.18
18.53-
23.75
2.33
20.76-
0.19
(kg)
Height BMI (kg/m2)
25.33
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(cm)
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Mean
27.98
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SD=Standard deviation, BMI=Body mass index
Table 2. Multifidus muscle size in healthy and LBP groups Variables
Groups
Mean
Mean
t-value
difference
RMLD (cm)
Healthy
0.73
LBP
0.67
Healthy LBP
RCSA (cm2)
Healthy
LAPD (cm)
LCSA (cm2)
p-value
interval
2.26
0.01-0.13
0.027
0.08
3.39
0.03-0.19
0.035
0.17
2.37
0.02-0.22
0.025
0.05
2.21
0.01-0.11
0.028
0.17
2.24
0.11-0.43
0.019
0.20
2.35
0.01-0.29
0.020
1.63
1.24
1.09
Healthy
0.69
LBP
0.64
Healthy
1.82
LBP
1.65
Healthy
1.25
LBP
1.05
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LMLD (cm)
1.71
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LBP
0.06
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RAPD (cm)
Confidence
RAPD=Right antero-posterior dimension, LAPD=Left antero-posterior dimension, RMLD=Right mediolateral dimension, LMLD=Left medio-lateral dimension, CSA=Cross sectional area
Table 3. Correlation between demographic variables and muscle size in two groups
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Variables
Health
Pearson
Age
Height
Weight
BMI
status
correlation
r
0.03
0.20
0.41
0.29
P
0.91
0.02
r
0.17
0.23
P
0.64
0.04
r
0.01
0.36
P
0.79
0.01
r
0.18
0.85
0.81
0.35
P
0.43
0.01
0.01
0.03
r
0.02
0.43
0.14
0.10
coefficient / P
LBP
RML
Healthy
LBP
RCSA
Healthy
P LBP
r P
LAP
Healthy
r P
LBP
r
LML
Healthy
LBP
Healthy
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LBP
0.22
0.18
0.02
0.02
0.18
0.20
0.04
0.02
0.01
0.02
0.01
0.09
0.56
0.55
0.31
0.81
0.04
0.04
0.02
0.04
0.13
0.13
0.22
0.12
0.01
0.01
0.02
0.03
0.27
0.17
0.28
0.93
0.04
0.01
0.02
r
0.02
0.19
0.11
0.37
P
0.87
0.01
0.03
0.04
r
0.05
0.70
0.61
0.25
P
0.90
0.03
0.04
0.04
r
0.15
0.39
0.23
0.30
P
0.71
0.01
0.02
0.03
r
0.04
0.52
0.38
0.12
P
0.91
0.04
0.02
0.02
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LCSA
0.04
0.62
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P
0.01
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Healthy
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RAP
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value
BMI=Body mass index, LBP=Low back pain, RAP=Right antero-posterior, LAP=Left antero-posterior, RML=Right medio-lateral, LML=Left medio-lateral, RCSA=Right cross sectional area, LCSA=Left cross sectional area
Table 4. Correlation between pain intensity and functional disability with muscle size Variables
Pearson
Pain intensity
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Functional
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correlation
disability level
coefficient / Pvalue
LAP
LML
LCSA
-0.56
P
0.01
0.01
r
-0.24
P
0.02
r
-0.33
P
0.02
r
-0.25
P
0.02
r
-0.25
P
0.04
r P
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RCSA
-0.16
-0.57 0.01
-0.22 0.03
-0.27
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RML
r
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RAP
0.02
-0.37 0.02
-0.34
-0.22
0.02
0.04
RAP=Right antero-posterior, LAP=Left antero-posterior, RML=Right medio-lateral, LML=Left medio-
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lateral, RCSA=Right cross sectional area, LCSA=Left cross sectional area
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