Morphologic Characteristics of the Deep Cervical Paraspinal Muscles in Patients with Single-Level Cervical Spondylotic Myelopathy

Journal Pre-proof Morphological characteristics of the deep cervical paraspinal muscles in patients with single level cervical spondylotic myelopathy Xiaofei Hou, MD, Shibao Lu, MD, Baobao Wang, MD, Chao Kong, MD, Hailiang Hu, MD PII:

S1878-8750(19)32606-3

DOI:

https://doi.org/10.1016/j.wneu.2019.09.162

Reference:

WNEU 13462

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World Neurosurgery

Received Date: 18 August 2019 Revised Date:

29 September 2019

Accepted Date: 30 September 2019

Please cite this article as: Hou X, Lu S, Wang B, Kong C, Hu H, Morphological characteristics of the deep cervical paraspinal muscles in patients with single level cervical spondylotic myelopathy, World Neurosurgery (2019), doi: https://doi.org/10.1016/j.wneu.2019.09.162. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. 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. © 2019 Elsevier Inc. All rights reserved.

Morphological characteristics of the deep cervical paraspinal muscles in patients with single level cervical spondylotic myelopathy Xiaofei Hou1, MD, Shibao Lu1* , MD, Baobao Wang1, MD, Chao Kong1, MD, Hailiang Hu1 MD 1

Departmnt of Orthopaedics, Xuanwu Hospital of Capital Medical University,

Beijing, China Correspondence to: Professor Shibao Lu, MD, Department of Orthopaedics, Xuanwu Hospital of Capital Medical University, 45 Changchun Street, Xicheng District, Beijing 100053, P.R. China. E mail: [email protected] Key words: Cervical spondylotic myelopathy, paraspinal muscles, Fat infiltration, MRI.

Running title: Characteristics of Paraspinal Muscles in single level CSM patients

This study was supported by the Beijing Natural Science Foundation（7174366）.

The

Manuscript

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device(s)/drug(s).

The authors declare no conflict of interest. .

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Morphological characteristics of the deep cervical paraspinal muscles in patients with single level cervical spondylotic myelopathy Abstract Objective: This study aimed to compare morphological changes of deep paraspinal muscles at C4-C7 in patients with C5/6 single-level cervical spondylotic myelopathy (CSM), and evaluate the relationship between morphological changes and the level of spinal cord compression.

Methods: The study included 15 C5/6 single-level CSM patients, and 15 age- and sex-matched healthy subjects. Cross-sectional area (CSA) and functional CSA of bilateral longus capitis (LCap), longus colli (LC), multifidus (MF), semispinalis cervicis (SSC), semispinalis capitis, splenius capitis, and splenius cervicis were measured on preoperative MR images at C4-7, and calculated as ratios with respect to the corresponding vertebral body CSA.

Results: The mean maximum spinal cord compression was 22.30% in CSM group. At the cranial level (C4/5), the CSM group had more fat infiltration in MF and SSC (P < 0.05). At the spinal cord compression segment and caudal adjacent segment (C5/6, C6/7), the degree of fat infiltration of all paravertebral muscles was aggravated, accompanied by atrophy of LCap, LC and MF (P < 0.05). Compared between different levels, fat infiltration in MF at C5/6 was greater than adjacent levels.

Conclusions: In C5/6 single level CSM patients, fat infiltration and atrophy of deep paraspinal muscles especially Lcap, LC and MF mainly occurred in the level of spinal cord compression and caudal adjacent level. In cranial adjacent segment, the degree of MF and SSC fat infiltration in CSM patients was also aggravated. These may suggest that multiple mechanisms are involved in paraspinal muscles degeneration in CSM.

Keywords Cervical spondylotic myelopathy, Paraspinal muscles, Fat infiltration.

Introduction The paraspinal muscles of the cervical spine play an important role in maintaining normal cervical curvature, stability, and activity1,2. Current studies have shown that changes in cervical paraspinal muscle morphology (such as fat infiltration) are associated with a variety of cervical spine diseases. Furthermore, the paraspinal muscles are sometimes atrophied in patients with whiplash-type injury or chronic neck and shoulder pain3,4. However, few studies have evaluated the paraspinal muscles of patients with cervical spondylotic myelopathy (CSM)5-7. Thus, the morphological changes in the paraspinal muscles of patients with CSM are still unclear. In the present study, to elucidate the paravertebral muscle characteristics of patients with CSM and minimize the effects of confounding factors, we compared the axial MR imaging data of patients with C5/6 single-level CSM versus sex- and age- matched normal healthy subjects, especially focused on fat infiltration and muscle atrophy.

Materials and methods Subjects

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We retrospectively reviewed the medical records of 15 patients aged 50–70 years who were diagnosed with C5/6 single-level CSM between November 2015 and March 2019 in our hospital. All of the patients had at least one clinical symptom and sign of myelopathy including clumsy hands, impairment of gait, weakness of the hands/arms, hyperreflexia, positive Hoffman and/or Babinski sign as a result of spinal stenosis at the level of C5-C6. All patients either failed in conservative treatment for at least 3 months or experienced progressive neurological deficits. We included patients who underwent standing cervical spine plain radiography, and cervical spine CT and MRI. The exclusion criteria were multilevel CSM, previous cervical surgery, cervical spine infection, fracture, spinal tumor, ossification of the posterior longitudinal ligament, inflammatory rheumatic diseases, and insufficient radiological or medical records. The control group comprised 15 healthy age- and sex-matched volunteers who underwent MRI of the cervical spine. The control subjects had no neck or radicular pain, other discomfort attributable to CSM, or history of neck trauma. Demographic data including age, sex, height, weight, and body mass index were recorded. The present study was approved by the Institutional Ethical Review Board for Clinical Studies at our institution.

Cervical Muscle Measurements For all participants, axial T2-weighted spin echo (TE/TR 90/3000 milliseconds) MR images between the C4 and C7 segments were acquired using a 3T MR scanner (Magnetom Trio, Siemens) with a head and neck coil. The C4/5, C5/6, and C6/7 paraspinal muscle areas and corresponding vertebral areas were measured at the most superior lines of the C5, C6, and C7 vertebral bodies on axial MR slices. In all participants, the total cross-sectional area (CSA) and functional CSA (FCSA) of the longus capitis (LCap), longus colli (LC), multifidus (MF), semispinalis cervicis (SSC), semispinalis capitis, splenius capitis (SpCap), and splenius cervicis were measured bilaterally using ImageJ image analysis software (version 1.52α, National Institutes of Health, Bethesda, Maryland). The above mentioned muscle areas were measured in accordance with the MRI atlas of the cervical spine musculature8 (Fig 1a). The FCSA was measured using the thresholding technique described in a previous study9 (Fig 1b). Briefly, four sample regions of interest within the bilateral paraspinal muscle group of each axial slice were taken from areas of lean muscle tissue to determine the maximum value. The maximum value was used as the highest cutoff value to distinguish muscle tissue from fat, while 0 was regarded as the lower limit. The relative % asymmetry of the paraspinal muscles on axial view was calculated as [(L– S)/L)] × 100, where L was the larger FCSA, and S was the smaller FCSA5. Maximum spinal cord compression was used to measure the maximum degree of spinal cord compression10. Maximum spinal cord compression was determined by the anteroposterior spinal cord diameter at the level of the highest spinal cord compression on sagittal imaging and by comparing it with the average of the diameters of 2 adjacent nonpathologic cord segments. (Figure 1a).

Statistical Analysis Means and standard deviations were calculated for the cervical muscle measurements. Student t-tests were used to compare the differences between the CSM and control groups in the

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FCSA/CSA ratio, FCSA/vertebral body CSA (VCSA) ratio, and FCSA asymmetry at the C5, C6, and C7 levels. One-way ANOVA was used to assess the difference between the sagittal FCSA/CSA

of

each

paraspinal

muscle

at

the

assessed

spinal

levels.

Fisher exact test was used for assessing baseline data. Differences with P values of <0.05 were considered statistically significant. All data measurements were performed by two independent surveyors. Each investigator measured twice. The interval between the two measurements was one week. The intra- and interobserver intraclass correlation coefficients were calculated to assess the reliability of the measurements. All analyses were performed with SPSS 19.0 (SPSS, Inc., Chicago, IL, USA).

Results Table 1 summarizes the demographic characteristics of the two groups. There were no significant differences between groups in sex ratio, age, body mass index and other baseline characteristics. In the CSM group, the mean duration of preoperative symptoms was 37.91 months, and the mean neck disability index (NDI) and Japanese Orthopaedic Association (JOA) scores were 39.37% and 11.73, respectively. Two-thirds of patients are with Nurick grade 2. Glove like sensory loss in hands (86.67%) and hyperreflexia (86.67%) were the most reported symptom and sign. The mean maximum spinal cord compression was 22.30%. (Table 2). At the C4/5 level, there were no significant differences between the CSM and control groups in the FCSA/CSA and FCSA/VCSA ratios of the LCap and the LC. The FCSA/CSA ratios of the MF and SSC were significantly smaller in the CSM group than in the control group(P < 0.05). The measurements of the other posterior cervical muscles did not significantly differ between the two groups. (Table 3). At the C5/6 segment, the mean FCSA/CSA and FCSA/VCSA ratios of the LCap and LC were smaller in the CSM group than in the control group(P < 0.05). Among posterior paraspinal

110

muscles，the FCSA/CSA and FCSA/VCSA ratios of the MF in the CSM group were lower than

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those in the control group(P < 0.05). The FCSA/CSA ratios of the other dorsal muscles in the CSM group were significantly lower than those in the control group(P < 0.05); however, the FCSA/VCSA ratios between the groups were not significantly different.(Table 4). At the C6/7 disc level, the FCSA/CSA and FCSA/VCSA ratios of the LCap, LC, MF, SpCap, and splenius cervicis in the CSM group were significantly smaller than those in the control group(P < 0.05). The FCSA/CSA ratios of the other paravertebral muscles were smaller in the CSM group than the control group(P < 0.01); however, the FCSA/VCSA ratios had no statistical differences between groups. (Table 5). The two groups did not significantly differ regarding the asymmetry of the paraspinal muscles, or the FCSA ratio of the anterior flexor muscles to the posterior extensor muscles. In the longitudinal comparison of fat infiltration in each deep paraspinal muscle, the CSM group had a greater degree of fat infiltration in the MF at C5/6 than at C4/5, while no significant differences of fat infiltration degree in other muscles were found between spinal levels. In the control group, the FCSA/CSA ratios of the LCap and LC increased from the cephalad to the caudal spinal levels at C4-C7(P < 0.05).

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The intra- and interobserver reliabilities were good (0.86 and 0.92, respectively).

Discussion The present case-control study evaluated the MRI features, particularly the fat infiltration and muscle atrophy, of the deep cervical paraspinal muscles of the cervical spine in 50–70-year-old patients with single-level C5/6 CSM. At the level of the C5/6, the spinal cord compression and the distal adjacent level, the CSM group had a greater degree of fat infiltration in all deep paravertebral muscles (including the flexor and extensor muscles) than the control group and had obvious muscle atrophy of LCap, LC, and MF. At the level of C4/5, even without spinal cord compression, significant fat degeneration was found in MF and SSC in CSM patients. The paraspinal muscles are innervated by the dorsal branches of the adjacent spinal nerves. Thus, the structure of the paraspinal muscles may be affected by spinal cord compression or nerve root damage11, which could explain the phenomenon that more obvious fat infiltration and atrophy of paraspinal muscles at spinal cord compression segment and distal adjacent level. In this study, we found that the degree of fat infiltration of the MF and SSC above the compression segment was also significantly higher than that of the control group. There are several possible reasons for this phenomenon. First, patients with CSM usually have reduced cervical lordosis angles and cervical extension ranges of motion compared with age-matched control subjects12, and cervical curvature abnormality is closely related to morphological changes in the paravertebral muscles13. Therefore, the degree of fat infiltration in the paravertebral muscles proximal to the compressed spinal cord may be related to abnormal cervical curvature. Second, some patients with CSM avoid neck activity due to local discomfort or fear of symptom aggravation, which could lead to disuse atrophy of the paraspinal muscles at uncompressed spinal cord levels14. In addition, this may be a natural course. Under physiological conditions, the volume of the cervical paraspinal muscles degenerate with age15. It is possible that severe cervical paraspinal muscle degeneration breaks the cervical spine homeostasis and accelerates the onset of CSM. There may be a very complex interaction between paravertebral muscle degeneration and CSM, or even be a vicious circle. The answer to this question depends on high-quality, prospective studies. In this study, we found for the first time that patients with CSM have an increased degree of fat infiltration and muscle atrophy of LCa and LC at the spinal cord compression level and the caudal adjacent level. LCa originates from the anterior tubercles of the C3–C6 transverse processes, passing superiorly before inserting onto the inferior aspect of the basoocciput. LC spans between the anterior arch of C1 and vertebral body of T37. Both LCa and LC are reported to contribute to the maintenance of cervical posture, control intervertebral motion, and counteract the lordosis increment exacerbated by gravitational forces and contraction of the dorsal neck muscles16,17. Degeneration and dysfunction of LCa and LC are associated with cervical curvature abnormality, neck pain and proprioception degradation18. Patients with CSM are usually associated with the above symptoms19. Whether these symptoms in CSM patients are related to the degeneration of LCa and LC has not been reported in the literature. Further study is required to clarify the role of fat infiltration and atrophy of LCa and LC in the development of CSM. The present study did not find any significant difference in paravertebral muscle asymmetry

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between the CSM and control groups. Previous studies evaluating paravertebral muscle symmetry in spinal diseases have reported conflicting results. This may be due to the measurement results of paravertebral muscles influenced by many factors, such as the duration of CSM symptoms20, and the selected measurement levels21. To improve the comparability of the results of different studies, it is necessary to establish a unified operation process. The current study had several limitations. First, the study was retrospective research. Second, we did not consider the effect of preoperative conservative treatment on the paraspinal muscle morphology of patients with CSM. Third, the sample size was small. Forth, we only evaluated the paravertebral muscle morphology in patients with single-level CSM. It is not clear whether multilevel CSM patients had similar morphological changes. Fifth, in this study, MRI was the only method used to evaluate the paravertebral muscles. If other detection methods, such as ultrasound or CT, can be used at the same time, it will undoubtedly increase the reliability of the research results. Despite the limitations mentioned above, this is the only case control study investigating the deep paravertebral muscle morphological features in single level CSM patients. We believe that the present study effectively minimized the confounding factors and these results will further clarify morphological changes in cervical deep paraspinal muscles in patients with CSM. Future studies should explore the specific role of these muscle degeneration in the development of CSM, and whether the pathogenesis of CSM can be changed by reasonable paraspinal muscle functional exercise. Conclusions A significant increase of fat infiltration of all deep cervical paravertebral muscles was observed at the level of spinal cord compression and distal adjacent segment, accompanied by atrophy of LCap, LC and MF. In the uncompressed proximal adjacent segment, the degree of MF and SSC fat infiltration in CSM patients was also aggravated. Our results suggested that fat infiltration and atrophy of deep paraspinal muscles in CSM patients may be due to different mechanisms. References 1. Anderson JS, Hsu AW, Vasavada AN. Morphology, architecture, and biomechanics of human cervical multifidus. Spine (Phila Pa 1976). 2005;30(4):E86-91. 2. Boyd-Clark LC, Briggs CA, Galea MP. Muscle spindle distribution, morphology, and density in longus colli and multifidus muscles of the cervical spine. Spine (Phila Pa 1976). 2002;27(7):694-701. 3. Elliott JM. Are there implications for morphological changes in neck muscles after whiplash injury? Spine (Phila Pa 1976). 2011;36(25 Suppl):S205-10. 4. Rezasoltani A, Ahmadipoor A, Khademi-Kalantari K, Javanshir K. The sign of unilateral neck semispinalis capitis muscle atrophy in patients with chronic non-specific neck pain. J Back Musculoskelet Rehabil. 2012;25(1):67-72. 5. Fortin M, Dobrescu O, Courtemanche M, Sparrey CJ, Santaguida C, Fehlings MG, Weber MH. Association between paraspinal muscle morphology, clinical symptoms, and functional status in

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patients with degenerative cervical myelopathy. Spine (Phila Pa 1976). 2017;42(4):232-239. 6. Cloney M, Smith AC, Coffey T, Paliwal M, Dhaher Y, Parrish T, Elliott J, Smith ZA. Fatty infiltration of the cervical multifidus musculature and their clinical correlates in spondylotic myelopathy. J Clin Neurosci. 2018;57:208-213. 7. Thakar S, Mohan D, Furtado SV, Sai Kiran NA, Dadlani R, Aryan S, Rao AS, Hegde AS. Paraspinal muscle morphometry in cervical spondylotic myelopathy and its implications in clinicoradiological

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2014;21(2):223-30. 8.Au J, Perriman DM, Pickering MR, Buirski G, Smith PN, Webb AL. Magnetic resonance imaging atlas of the cervical spine musculature. Clin Anat. 2016;29(5):643-59. 9. Fortin M, Battié MC. Quantitative paraspinal muscle measurements: inter-software reliability and agreement using OsiriX and ImageJ. Phys Ther. 2012;92(6):853-64. 10. Wei L, Cao P, Xu C, Wu H, Hu B, Tian Y, Yuan W. Comparison of the prognostic value of different quantitative measurements of increased signal intensity on T2-weighted MRI in cervical spondylotic myelopathy. World Neurosurg. 2018;118:e505-e512. 11. Hayashi N, Masumoto T, Abe O, Aoki S, Ohtomo K, Tajiri Y. Accuracy of abnormal paraspinal muscle findings on contrast-enhanced MR images as indirect signs of unilateral cervical root-avulsion injury. Radiology. 2002;223(2):397-402. 12. Machino M, Yukawa Y, Imagama S, Ito K, Katayama Y, Matsumoto T, Inoue T, Ouchida J, Tomita K, Ishiguro N, Kato F. Age-related and degenerative changes in the osseous anatomy, alignment, and range of motion of the cervical spine. Spine (Phila Pa 1976). 2016;41(6):476-82. 13. Yoon SY, Moon HI, Lee SC, Eun NL, Kim YW. Association between cervical lordotic curvature and cervical muscle cross-sectional area in patients with loss of cervical lordosis. Clin Anat. 2018;31(5):710-715. 14. Wesselink E, de Raaij E, Pevenage P, van der Kaay N, Pool J. Fear-avoidance beliefs are associated with a high fat content in the erector spinae: a 1.5 tesla magnetic resonance imaging study. Chiropr Man Therap.2019; 27:14. 15. Okada E, Matsumoto M, Ichihara D, Chiba K, Toyama Y, Fujiwara H, Momoshima S, Nishiwaki Y, Takahata T. Cross-sectional area of posterior extensor muscles of the cervical spine in asymptomatic subjects: a 10-year longitudinal magnetic resonance imaging study. Eur Spine J. 2011;20(9):1567-73. 16. Mayoux-Benhamou MA, Revel M, Vallee C, Roudier R, Barbet JP, Bargy F. Longus colli has a postural function on cervical curvature. Surg Radiol Anat. 1994;16:367–371. 17. Boyd-Clark LC, Briggs CA, Galea MP. Comparative histochemical composition of muscle fibres in a pre- and a postvertebral muscle of the cervical spine. J Anat. 2001; 199:709–716. 18. Amiri Arimi S, Ghamkhar L, Kahlaee AH. The relevance of proprioception to chronic neck pain: A correlational analysis of flexor muscle size and endurance, clinical neck pain characteristics, and proprioception. Pain Med. 2018;19(10):2077-2088. 19. Lin IS, Lai DM, Ding JJ, Chien A, Cheng CH, Wang SF, Wang JL, Kuo CL, Hsu WL. Reweighting of the sensory inputs for postural control in patients with cervical spondylotic myelopathy after surgery. J Neuroeng Rehabil. 2019;16(1):96.

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20. Kim WH, Lee SH, Lee DY. Changes in the cross-sectional area of multifidus and psoas in unilateral

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2011;50(3):201-204. 21. Kang JI, Kim SY, Kim JH, Bang H, Lee IS. The location of multifidus atrophy in patients with a single level, unilateral lumbar radiculopathy. Ann Rehabil Med. 2013;37(4):498-504.

Acknowledgments We thank Kelly Zammit, BVSc, from Liwen Bianji, Edanz Group China (www.liwenbianji.cn/ac), for editing the English text of a draft of this manuscript.

Figure legends Figure 1. (a) Calculation of maximum spinal cord compression. The Di is the anteroposterior spinal cord diameter at the level of the highest spinal cord compression on sagittal imaging, Da is the anteroposterior spinal cord diameter at the first normal vertebral segment above, and Db is the anteroposterior spinal cord diameter at the first normal vertebral segment below. (b) Measurement of cross-sectional area of multifidus muscle (left, area within the yellow circle) on axial T2-weighted magnetic resonance imaging image at C5/6. (c) The image shows the application of a signal threshold filter (ImageJ, ver. 1.52α) to highlight the fat-free muscle area and obtain the functional cross-sectional area of left multifidus muscle (red area within the yellow circle). Figure 2. Variation tendency of mean FCSA/CSA in the cervical deep paraspinal muscles across segmental vertebral levels (C4–C7) in the healthy control and CSM groups. LCap, longus capitis; LC, longus colli; MF, multifidus; SSC, semispinalis cervicis; SSCap, semispinalis capitis; SpCap, splenius capitis; SpC, splenius cervicis.

Table 1. Demographic and clinical characteristics of patients and controls enrolled in this study

Age(yr) Gender(F/M) BMI Diabetes Hypertension Smoking status Alcohol consumption Duration(mo)

CSM(n=15)

Control(n=15)

p-value

56.38±3.70 3/12 25.02±2.42 2 4 7 6 37.91±44.66

53.67±4.68 3/12 25.56±2.31 3 2 5 5 /

0.354 1.000 0.652 1.000 0.651 0.710 1.000 /

Table 2. Neurologic status and maximum spinal cord compression of DCM patients Patient Characteristics

Mean (SD) or %

Functional scores NDI JOA Nurick classfication Grade 2 Grade 3 DCM manifestations Glove like sensory loss in hands Proprioceptive dysfunction Weakness in triceps and hand intrinsics Clumsiness with fine motor skills Impairment of gait Hyperreflexia Babinski sign Hoffmann sign Mean maximum spinal cord compression

39.37%±18.80% 11.73±2.24 10 (66.67%) 5 (33.33%) 13 (86.67%) 7 (46.67%) 8 (53.33%) 10 (66.67%) 8 (53.33%) 13 (86.67%) 5 (33.33%) 10 (66.67%) 22.30%±10.75%

NDI, Neck Disability Index; JOA, Japanese Orthopaedic Association Scores. Data are mean ±SD.

Table 3. Fat infiltration of C4/5 segment of two groups using MRI Group LCap+LC

Multifidus

CSM

Control

P value

FCSA/CSA

0.55±0.19

0.63±0.10

0.348

FCSA/VCSA

0.35±0.18

0.34±0.11

0.993

FCSA asymmetry (%)

0.23±0.12

0.19±0.12

0.609

FCSA/CSA

0.30±0.12

0.45±0.08

0.017*

SSC

SSCap

SpCap+SpC

FCSA/VCSA

0.26±0.13

0.24±0.10

0.816

FCSA asymmetry (%)

0.24±0.17

0.29±0.24

0.707

FCSA/CSA

0.50±0.12

0.67±0.07

0.009*

FCSA/VCSA

0.48±0.20

0.63±0.17

0.160

FCSA asymmetry (%)

0.25±0.18

0.20±0.17

0.624

FCSA/CSA

0.41±0.13

0.52±0.19

0.197

FCSA/VCSA

0.74±0.26

0.78±0.41

0.848

FCSA asymmetry (%)

0.33±0.10

0.28±0.14

0.398

FCSA/CSA

0.37±0.21

0.53±0.18

0.166

FCSA/VCSA

0.65±0.35

0.82±0.44

0.432

FCSA asymmetry (%)

0.42±0.27

0.49±0.21

0.614

0.17±0.09

0.15±0.06

0.571

TFFCSA/TEFCSA

*P<0.05. CSA, cross sectional area; FCSA, functional cross sectional area; VCSA, vertebral cross sectional area; TFFCSA, total flexor muscle functional cross sectional area; TEFCSA, total extensor muscle functional cross sectional area.

Table 4. Fat infiltration of C5/6 segment of two groups using MRI Group LCap+LC

Multifidus

SSC

SSCap

SpCap+SpC

TFFCSA/TEFCSA

CSM

Control

P value

FCSA/CSA

0.49±0.13

0.68±0.04

0.005*

FCSA/VCSA

0.18±0.06

0.27±0.08

0.030*

FCSA asymmetry (%)

0.12±0.07

0.17±0.15

0.456

FCSA/CSA

0.17±0.10

0.51±0.20

0.001*

FCSA/VCSA

0.10±0.07

0.32±0.22

0.023*

FCSA asymmetry (%)

0.38±0.24

0.20±0.19

0.152

FCSA/CSA

0.39±0.21

0.72±0.15

0.007*

FCSA/VCSA

0.44±0.25

0.62±0.05

0.070

FCSA asymmetry (%)

0.25±0.18

0.20±0.14

0.568

FCSA/CSA

0.29±0.13

0.49±0.12

0.013*

FCSA/VCSA

0.36±0.22

0.61±0.41

0.168

FCSA asymmetry (%)

0.34±0.14

0.25±0.23

0.368

FCSA/CSA

0.36±0.19

0.61±0.12

0.018*

FCSA/VCSA

0.48±0.29

0.79±0.33

0.086

FCSA asymmetry (%)

0.42±0.27

0.31±0.17

0.404

0.16±0.09

0.12±0.04

0.351

*P<0.05.

Table 5. Fat infiltration of C6/7 segment of two groups using MRI Group

CSM

Control

P value

LCap+LC

Multifidus

SSC

SSCap

SpCap+SpC

TFFCSA/TEFCSA

*P<0.05.

FCSA/CSA

0.63±0.14

0.80±0.08

0.021*

FCSA/VCSA

0.25±0.06

0.35±0.05

0.004*

FCSA asymmetry (%)

0.15±0.12

0.11±0.09

0.442

FCSA/CSA

0.22±0.13

0.54±0.14

0.001*

FCSA/VCSA

0.15±0.09

0.32±0.13

0.013*

FCSA asymmetry (%)

0.32±0.25

0.14±0.12

0.143

FCSA/CSA

0.49±0.16

0.77±0.11

0.003*

FCSA/VCSA

0.51±0.19

0.62±0.12

0.246

FCSA asymmetry (%)

0.20±0.13

0.16±0.13

0.639

FCSA/CSA

0.37±0.13

0.59±0.11

0.005*

FCSA/VCSA

0.29±0.11

0.46±0.23

0.080

FCSA asymmetry (%)

0.28±0.17

0.15±0.14

0.134

FCSA/CSA

0.41±0.19

0.69±0.09

0.006*

FCSA/VCSA

0.47±0.22

0.73±0.14

0.031*

FCSA asymmetry (%)

0.37±0.20

0.27±0.14

0.306

0.19±0.06

0.17±0.03

0.351

CSA: Cross-sectional area CSM: Cervical spondylotic myelopathy FCSA: Functional CSA JOA: Japanese Orthopaedic Association socre scores LC: Longus colli LCap: Longus capitis MF: Multifidus NDI: Neck disability index SSC: Semispinalis cervicis SSCap: Semispinalis capitis SpCap: Splenius capitis VCSA: Vertebral body CSA