J Korean Acad Rehab Med 2010; 34: 743-751 Original Article Cervical Multifidus Muscle Atrophy in Patients with Unilateral Cervical Radiculopathy

Sang Han Chae, M.D.1, Seong Jae Lee, M.D., Ph.D.1, Min Seok Kim, M.D.1, Tae Uk Kim, M.D.1, Jung Keun Hyun, M.D., Ph.D.1,2,3

Departments of 1Rehabilitation Medicine, College of Medicine, 2Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, 3Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheoan 330-715, Korea

Objective To assess the atrophy of cervical multifidus muscles in patients with unilateral cervical disc herniation or radiculopathy quantitatively and to investigate whether asymmetric muscle atrophy has the relationship with the severity of cervical disc herniation or radiculopathy.

Method Twenty-four patients who had cervical disc herniation in magnetic resonance imaging (MRI) were evaluated. The patients were divided into 2 groups; patients with unilateral cervical radiculopathy in electrodiagnosis (RAD) and patients without definite radiculopathy (HIVD). Twenty six controls without disc herniation were also evaluated. Cervical multifidus muscles from C4-5 to C7-T1 levels were detected in T1 axial MRI, and total cross-sectional area (CSA) of multifidus muscle (TMA) and pure muscle CSA (PMA) were measured.

Results The ratios of TMA in involved side to TMA in uninvolved side (ITMA/UTMA) and PMA in involved side to PMA in uninvolved side (IPMA/UPMA) in HIVD and RAD groups was significantly lower than those in control group especially at C7-T1 level (p＜0.05). We divided the levels of cervical spine into three parts according to lesions found in MRI or electrodiagnosis; above lesion level, at lesion level and below lesion level. Abnormal cases of IPMA/UPMA were not different among levels in HIVD group, but RAD group showed that most of abnormal cases were below lesion (60%).

Conclusion Asymmetric multifidus atrophy was seen in patients with cervical disc herniation and radiculopathy. The ratio of pure muscle CSA between involved and uninvolved sides might be a useful parameter to differentiate patients with unilateral cervical radiculopathy from patients without radiculopathy.

Key Words Cervical radiculopathy, Cross-sectional area, Multifidus muscle, Electrodiagnosis, Magnetic resonance imaging

INTRODUCTION es of neck pain include various lesions and trauma, such as cervical radiculopathy, myofascial pain syn- Neck pain is a very common symptom from which drome, and whiplash injury; however, cervical para- two of three people suffer during their lifetime,1 with spinal muscle weakness can also be a cause of neck more frequent occurrence in office workers.2 The caus- pain because cervical muscle weakness has been re-

Received April 22, 2010; Accepted August 26, 2010 Corresponding author: Jung Keun Hyun Department of Nanobiomedical Science, Dankook University, San 16-5 Anseo-dong, Dongnam-gu, Cheonan 330-715, Korea Tel: +82-41-550-6640, Fax: +82-41-551-7062, E-mail: [email protected] Copyright © 2010. Korean Academy of Rehabilitation Medicine Sang Han Chae, et al.

ported in patients with neck pain3 and strengthening signs suspicious of unilateral cervical radiculopathy by exercises of the neck could reduce neck pain.2,4 Cervical physiatrists in the department of rehabilitation medicine paraspinal muscle weakness may lead to cervical in- in Dankook University Hospital and diagnosed with cer- stability because critical load of osteoligamentous struc- vical disc herniation from the C4-5 to C7-T1 levels ture in the cervical spine has been reported in only through MRI were selected. This research was per- about 20% of the weight of head5 and the paraspinal formed in accordance with a research protocol ap- muscles surrounding the cervical region support the proved by the Institutional Review Board of Dankook rest of its weight. University and agreement forms were received from all Cervical paraspinal muscles are innervated by cer- subjects. Exclusion criteria included bilateral symptoms, vical roots; therefore, cervical radiculopathy can lead to signs or electrophysiologic findings, spinal fracture, spi- cervical paraspinal muscle atrophy. Using contrast-en- nal tumors or previous cervical spine operation affect- hanced magnetic resonance imaging (MRI), Hayashi et ing cervical paraspinal muscle abnormalities, and poly- al. reported that abnormal findings in unilateral para- neuropathy or peripheral nerve lesions affecting electro- spinal muscles were observed in patients with unilat- physiologic abnormalities. We also evaluated 26 normal eral cervical root avulsion injury.6 Atrophy or fatty in- controls, who had no clinical symptoms or signs and filtration of paraspinal muscles can be detected and no disc herniation in MRI for detection of a normal quantified using MRI and analysis software, and several range of cervical paraspinal and multifidus muscles. researchers have reported these findings in patients All subjects underwent cervical MRI and patients were with whiplash injury and chronic tension-type headache.7-9 also evaluated by electrophysiologic study using an elec- However, no study has reported on unilateral atrophy trodiagnostic machine (Medelec Synergy, Oxford Instru- in cervical paraspinal or multifidus muscles in cervical ments Medical, Inc., Oxfordshire, U.K). Electrodiagnostic radiculopathy and the relationships between unilateral criterion for cervical radiculopathy was the detection of muscle atrophy and cervical disc herniation or cervical abnormal spontaneous activities at rest in unilateral radiculopathy. cervical paraspinal muscles and/or involved upper ex- Therefore, this study was designed prospectively to tremity muscles, and this criterion was the same as delineate the atrophy of cervical multifidus muscles in that used in our previous study.10 We then divided pa- patients with unilateral cervical disc herniation or radi- tients into 2 groups: patients with unilateral cervical culopathy quantitatively and to investigate the question radiculopathy in electrodiagnosis (n=11; RAD) and pa- of whether asymmetric muscle atrophy has a relation- tients without definite radiculopathy (n=13; HIVD). ship with the severity of cervical disc herniation or There was no statistical difference in gender between radiculopathy. controls and patients (p=0.053); however, the number of females in the control group was greater than that in the patient groups. Mean ages in the control and the MATERIALS AND METHODS HIVD and RAD groups were 40.42 years, 47.25 years, and 54.88 years, respectively; therefore, the age in the Subjects RAD group was older than those in the control and Twenty four patients who had clinical symptoms and HIVD groups (Table 1). The symptom duration was de-

Table 1. Characteristics of Subjects

Controls HIVD RAD Total patients

Number of subjects 26 13 11 24 Age (years) 40.42±12.51 47.25±11.30 54.88±12.47* 49.80±12.00 Gender (M：F) 11：15 9：49：218：6 Symptom duration (months) − 7.32±8.90 4.75±7.59 6.19±8.20

Values indicate numbers or mean±standard deviation. HIVD: Patients with cervical disc herniation in MRI but no radiculopathy in electrodiagnosis, RAD: Patients with cervical disc herniation in MRI and unilateral radiculopathy in electrodiagnosis *p＜0.05 from the control group by one-way ANOVA with Bonferroni post hoc test

744 Cervical Multifidus Muscle Atrophy in Unilateral Cervical Radiculopathy

fined as the duration from the onset of clinical symp- were blinded to the subject’s clinical information, and toms or signs of suspicious unilateral cervical radiculop- the average of two values between the smallest and athy to the date in which patients received cervical largest values at each side in each level was used for MRI, and there was no difference of symptom duration quantitative analysis. between the HIVD and RAD groups (Table 1). Statistics Methods Statistical analysis was performed using SPSS 14.0 for MRI study was conducted on a 1.5 tesla MR scanner Windows. One-way analysis of variance and Bonferroni (Genesis-Signa Twin Speed, General Electric, Milwaukee, post hoc test were used for comparison of ages of con- WI, USA), and a T1-weighted fast spin-echo sequence trols and patients; chi-square test was used for com- was used. Axial images (Field of view=160 mm, TR= parison of gender in controls and patients, and in- 500 msec, TE=11 msec, flip angle α=90o, Section thick- dependent t-test was performed for comparison of the ness=3.0 mm, Matrix size=256×224) in four levels: C4-5, symptom duration between the HIVD and RAD groups. C5-6, C6-7, and C7-T1 were obtained and cross-sectional Kolmogorov-Smirnov test and Shapiro-Wilk test were areas on both sides at each level were measured using performed in order to reveal the normal distribution of an image analysis program (Rapidia analysis program, age, TMA, and PMA in controls and patients. Range of Infinitt, Seoul, Korea). At each level, images providing normal values of quantitative parameters in each level the best identification of both multifidus muscles were was determined within 2 standard deviations of the chosen among 2 or more slices at cervical disc levels. mean value or minimal value according to the optimal The Cross-sectional area (CSA) of each multifidus mus- sensitivity and specificity using ROC curves. cle was drawn manually using a mouse and a fat com- One-way analysis of variance and Bonferroni post hoc ponent in multifidus muscles was separated by the test were also performed for comparison of quantitative threshold technique based on visual differences in pixel parameters in each level from controls and the HIVD signal intensities (Fig. 1). and RAD groups, and Fisher’s exact test was performed Five parameters were used for quantitative analysis for comparison of numbers of abnormal cases in the of multifidus muscles; total muscle CSA (TMA), pure HIVD and RAD groups at each level and quantitative muscle CSA (PMA), which eliminates fat infiltration from parameters at three parts according to lesions found in TMA, ratio of PMA to TMA (PMA/TMA), ratio of TMA MRI or electrodiagnosis. Significance was determined at of the involved side to TMA of the uninvolved side p＜0.05. (ITMA/UTMA), and ratio of PMA of the involved side to PMA of the uninvolved side (IPMA/UPMA). All CSAs were measured independently two times by two resi- dents in the department of rehabilitation medicine, who

Fig. 1. Examples of C6-7 multi- fidus muscles in a patient with Lt. C6 radiculopathy shown in the axial plane of MRI. Both green lines indicate free regions of interest of the bilateral mul- tifidus muscle at the C6-7 level (A), and green color in the re- gion of interest (B) indicates pure muscle cross-sectional areas of both multifidus muscles. Lt. multifidus muscle contains more fat tissue than Rt. multifidus muscle.

745 Sang Han Chae, et al. d f d,f d b b b f,g f,d,g b,c b,c b,c . . s s ＜＞ . . ＜＞ ＜＞ ＜＞ n.s. ＜＞ ＜＞ ＜＞ ＜＞ g n.s. n.s. ＜＞ ＜＞ d ＜＞ d ＜＞ ＜＞ ＜＞ ＜＞ Post hoc 5n 1n 50 0.077 0.067 0.001* a 0.002* a 0.000* a 0.000* a,c 0.000* a,c 0.001* a,c p-value ved ved side, IPMA: Pure muscle cross ninvolved side, n.s.: not significant multifidus muscle, ITMA: Total cross 40.022*a 3 0.001* a,e 70.002*a 8 0.021* d,f 33 0.001*79 0.000* a,d a,e 55 0.000* a,e,f,g g c Involved f 0.83±0.23 0.83±0.41 0.72±0.25 0.88±0.11 0.88±0.05 0.93±0.04 0.97±0.10 0.94±0.14 RAD RAD (n=11) Uninvolved e b Involved vel vel in Controls and Patients. d 0.87±0.23 0.86±0.26 0.76±0.30 0.86±0.14 0.85±0.13 0.84±0.16 0.84±0.16 0.77±0.20 HIVD HIVD (n=13) Total cross sectional area of multifidus muscle in the uninvol the in muscle multifidus of area sectional cross Total culopathy in electrodiagnosis, RAD: Patients with cervical disc herniation in MRI and unilateral rad- unilateral and MRI in herniation disc cervical with Patients RAD: electrodiagnosis, in culopathy of multifidus muscle, PMA: Pure muscle cross sectional area of area sectional cross muscle Pure PMA: muscle, multifidus of Uninvolved a (n=52) Control C5-6C6-7C7-T1 1.00±0.23 1.04±0.16 0.99±0.13 C7-T1 0.99±0.11 C6-7 0.98±0.10 C5-6C7-T1 174.04±24.02 185.18±26.20 203.85±25.52 231.00±14.91 171.81±37.86 196.28±37.45 183.92±41.50 227.58±22.74 170.67±39.1 200.66±26. C6-7 176.77±23.70 201.02±38.45 172.75±42.63 213.80±24.77 186.18±25.9 C5-6 1.00±0.10 C4-5 178.94±23.59 197.81±36.08 164.63±35.51 155.65±36.00 151.19±36. C5-6C6-7C7-T1 0.78±0.16 0.75±0.17 0.72±0.20 0.82±0.09 0.79±0.14 0.74±0.16 0.84±0.13 0.78±0.18 0.62±0.18 0.87±0.08 0.64±0.18 0.66±0.26 0.76±0.19 0.59±0.28 0.53±0.26 0.30 0.05 0.0 C7-T1 129.28±27.52 171.78±41.83 125.49±50.12 147.11±52.21 102.60±47.77 0.000 a,e,g C6-7 129.60±20.86 156.99±35.37 132.90±42.44 137.33±45.24 109.10±58.1 C5-6 133.23±19.61 168.55±32.03 145.54±41.09 159.36±38.04 132.44±49.6 C4-5 126.21±17.18 171.40±31.67 129.43±30.46 136.95±32.90 128.97±35. C4-5 0.72±0.13 0.87±0.08 0.78±0.08 0.88±0.07 0.85±0.78 0.000 e,a Level ) ) 2 2 Cross Cross Sectional Area of Bilateral Multifidus Muscles at Each Le 0.05 by one-way ANOVA with Bonferroni post hoc test Parameter ＜ sectional sectional area of multifidus muscle sectional in area of the multifidus involved muscle side, in *p UTMA: the involved side, UPMA: Pure muscle cross sectional area of multifidus muscle in the u Values indicate mean±standard deviation. HIVD: Patients with cervical disc herniation in MRI but no radi iculopathy iculopathy in electrodiagnosis, TMA: Total cross sectional area IPMA/UPMA C4-5 1.03±0.13 Table 2. (mm TMA (mm PMA ITMA/UTMA C4-5 1.00±0.09 PMA/TMA

746 Cervical Multifidus Muscle Atrophy in Unilateral Cervical Radiculopathy

RESULTS and at the C6-7 and C7-T1 levels in the RAD group was lower than that in controls (Table 2). IPMA/UPMA Comparison of quantitative parameters among the at the C4-5 and C7-T1 levels in the HIVD and RAD control, HIVD, and RAD groups groups was lower than that in controls (Table 2). TMA at the C4-5 level in the RAD group was smaller Normal values of TMA, PMA, and PMA/TMA were set than those in the control and HIVD groups; however, within 2 standard deviations of the mean value, and overall TMA was not significantly different among con- normal values of ITMA/UTMA and IPMA/UPMA were trols and the two patient groups (Table 2). PMA in the set to minimal value according to detection of optimal involved side (IPMA) was smaller than PMA in the un- sensitivity and specificity. involved side (UPMA) at the C4-5 and C7-T1 levels in the HIVD group, and at the C6-7 and C7-T1 levels in Comparison of abnormal cases at each level in the RAD group (Table 2). TMA and PMA at each level patients and age distribution in controls and the two patient The most frequent level of disc herniation was the groups showed normal distribution. PMA/TMA was not C7-8 level (8 cases, 61.5%) in the HIVD group and the different at most levels in controls and the two patient C5-6 level (7 cases, 63.6%) in the RAD group; however, groups. ITMA/UTMA at all levels in the HIVD group there was no statistical significance between the HIVD and RAD groups (Table 3). The most frequent level of cervical radiculopathy was the C7 level (6 cases, 54.5%), Table 3. Cases of Disc Herniation and Radiculopathy in and then the C6 level (36.4%), and the C8 level (18.2%) the HIVD and Radiculopathy Groups in the RAD group (Table 3). Disc herniation in multiple levels was found in 5 patients (38.5%) in the HIVD RAD (n=11) Disc level HIVD group, and cervical radiculopathy in multiple levels was /Root level (n=13) Disc herniation radiculopathy found in one patient (9.1%) in the RAD group.

C4-5/C5 5 (38.5) 2 (18.2) 1 (9.1) C5-6/C6 6 (46.2) 7 (63.6) 4 (36.4) Comparison of quantitative parameters by the level C6-7/C7 8 (61.5) 6 (54.5) 6 (54.5) of disc herniation or radiculopathy C7-T1/C8 2 (15.4) 4 (36.4) 2 (18.2) Quantitative parameters were analyzed by the level of disc herniation or radiculopathy in controls and the Values indicate numbers of abnormal cases (%). two patient groups (Table 4). The number of cases was HIVD: Patients with cervical disc herniation in MRI but no radiculopathy in electrodiagnosis, RAD: Patients with cer- 104 (26 cases at the C4-5, C5-6, C6-7, and C7-T1 lev- vical disc herniation in MRI and unilateral radiculopathy els) in controls, 52 (n=13) in the HIVD group, and 44 in Electrodiagnosis (n=11) in the RAD group.

Table 4. Comparison of Abnormal Cases of Meaningful Parameters in Patients with Cervical Disc Herniation and Patients with Cervical Radiculopathy According to the Lesion Level

HIVD RAD

Above lesion Lesion level Below lesion Above lesion Lesion level Below lesion level (n=12) (n=13) level (n=27) level (n=17) (n=12) level (n=15)

PMA 3 (25.0) 2 (15.4) 5 (18.5) 3 (17.6) 2 (16.7) 8 (53.3) ITMA/UTMA 6 (50.0) 8 (61.5) 10 (37.0) 1 (5.9) 1 (8.3) 4 (26.7) IPMA/UPMA 5 (41.7) 6 (46.2) 8 (29.6) 0 (0) 3 (25.0) 9 (60.0)*

Values indicate numbers of abnormal cases (%). HIVD: Patients with cervical disc herniation in MRI but no radiculopathy in electrodiagnosis, RAD: Patients with cervical disc herniation in MRI and unilateral radiculopathy in Electrodiagnosis, PMA: Pure muscle cross sectional area of multifidus muscle, ITMA: Total cross sectional area of multifidus muscle in the involved side, UTMA: Total cross sectional area of multifidus muscle in the uninvolved side, IPMA: Pure muscle cross sectional area of multifidus muscle in the involved side, UPMA: Pure muscle cross sectional area of multifidus muscle in the uninvolved side *p＜0.05 compared with the other two levels within the RAD group by Fisher’s exact test

747 Sang Han Chae, et al.

We divided the levels of the cervical spine into three niation or radiculopathy, as in our study. parts according to lesions found in MRI or electro- Lumbar disc herniation and muscle weakness on the diagnosis: above the lesion level, at the lesion level, back and abdominal muscles are the major causes of and below the lesion level, and PMA, ITMA/UTMA, and low back pain,14 and Campbell et al. reported on cases IPMA/UPMA, which were meaningful parameters in the of lumbosacral radiculopathies that showed selective two patient groups, compared with those in the control muscle atrophy in multifidus muscles innervated by in- group, were analyzed according to the above three volved roots.15 We also analyzed lumbosacral multifidus parts in the HIVD and RAD groups. Abnormal cases of and paraspinal muscles in patients with unilateral lum- PMA above the lesion level of disc herniation were the bosacral radiculopathies in a previous study, and found most (25%) in the HIVD group, and abnormal cases of that patients with lumbosacral radiculopathies diagnosed ITMA/UTMA and IPMA/UPMA at the lesion level of disc by electrophysiologic study showed asymmetric muscle herniation were 61.5% and 46.2%, respectively, in the atrophy of involved multifidus muscles and patients HIVD group; however, there was no statistical sig- with lumbosacral disc herniation and without lumbo- nificance according to the lesion levels (Table 4). Ab- sacral radiculopathy did not show unilateral multifidus normal cases of PMA, ITMA/UTMA, and IPMA/UPMA atrophy.10 However, in this study, patients who had were the most below the lesion level of cervical radi- cervical disc herniation without cervical radiculopathy culopathy in the RAD group, and, in particular, the pro- showed asymmetric muscle atrophy of multifidus mus- portion of abnormal cases of IPMA/UPMA below the le- cles (Table 2), and PMA and IPMA/UPMA of these pa- sion level of cervical radiculopathy was 60% and more tients showed no difference among the three parts ac- statistically significant than those above and at the le- cording to lesions found in MRI or electrodiagnosis sion levels in the RAD group (Table 4). The numbers (Table 4). Yoshihara et al. found that patients with L5 of patients who had abnormal IPMA/UPMA values were radiculopathy confirmed by surgical findings among pa- 9 (69.2%) and 7 (63.6%) in the HIVD and RAD groups, tients with L4-5 disc herniation showed multifidus mus- respectively, with no statistical significance between two cle atrophy at the L5 level,16 and Zhao et al. reported groups. on muscle atrophy of lumbosacral paraspinal muscles in patients with lumbosacral disc herniation who were not even confirmed as having lumbosacral radiculopathy.17 DISCUSSION In this study, 38.5% of the HIVD group had multiple levels of disc herniation, and clear division of parts ac- Cervical paraspinal muscles constitute the semispinalis cording to the lesion level was impossible in these capitis, semispinalis cervicis, and multifidus from the cases. Nevertheless, the relationship between disc her- posterior to the anterior direction. The multifidus mus- niation and multifidus muscle atrophy cannot be ex- cle is known to be innervated by a single root;11 there- plained in this study because muscle atrophy was fore, single cervical radiculopathy can be diagnosed by found in the HIVD group regardless of lesion levels. detection of abnormal spontaneous activities in involved We found that TMA and PMA in the uninvolved side multifidus muscle using needle electromyography.12 Haya- were larger in patient groups than in controls, and the shi et al. reported that the multifidus muscle was the reason for this was thought to be the difference of the most accurate and provided the highest sensitivity and proportion of gender (more females in patient groups) specificity among cervical paraspinal muscles that showed between controls and patient groups, although the dif- abnormal enhancement after unilateral cervical root ference was not statistical. avulsion injury in contrast-enhanced MRI.6 Hides et al. found asymmetric muscle atrophy of Muscle atrophy and fat infiltration in involved multi- L4-5 paraspinal muscles in patients with chronic low fidus muscle may be shown after cervical root com- back pain through ultrasound and insisted that low pression due to disc herniation; however, neck pain back pain may lead to muscle atrophy.18 Baker et al. without root involvement and trauma have also been found that muscle atrophy on the symptomatic side reported to cause muscle atrophy in neck flexors.7,8,13 was not associated with the level of pain area in pa- Therefore, patients who showed unilateral symptoms or tients with unilateral low back pain, and they explained signs suspicious of cervical radiculopathy should be se- this finding as disuse atrophy, which is the result of lected for differentiation with others without disc her- patients’ behavior in not using the involved muscles,

748 Cervical Multifidus Muscle Atrophy in Unilateral Cervical Radiculopathy

which can induce more back pain.19 Because most pa- found in mild cases or cases with mainly sensory tients with cervical disc herniation suffer from neck dysfunction. It is hard to gather patients with cervical pain, disuse muscle atrophy could progress in the HIVD radiculopathy because the proportion of patients with group in this study regardless of involved levels, like- cervical radiculopathy is only 5-10% of patients with wise in cases of patients with low back pain in pre- radiculopathies, and there was no study to compare with vious studies. our findings because most studies for analysis of multi- Patients with cervical radiculopathy showed muscle fidus muscles have focused on lumbosacral lesions.22 atrophy below the lesion level more than those at or The age of patients with cervical radiculopathy was above lesion levels in this study (Table 4). This finding older than that of controls in this study. Gilad et al. can be explained with the morphology of the multifidus found abnormal spontaneous activities in older persons muscle, which is originated from one articular process without any symptoms suspicious of cervical radiculop- on the lateral side, but generally inserted into two or athy;23 however, we included patients who had clinical three different spinous processes of the upper cervical symptoms or signs, and all subjects in this study had levels; therefore, multifidus muscles innervated at two cervical disc herniation, and another study reported or three roots can exist on the same horizontal plane; that there was no relationship between age and cer- however, one multifidus muscle is innervated by one vical muscle atrophy;7 therefore, the effect of aging on root.16,20 Because the horizontal plane at the lesion lev- abnormal electrodiagnostic findings and cervical muscle el includes multifidus muscles innervated from one or atrophy is not clear. two intact roots and the size of the multifidus muscle We did not investigate the correlation between the innervated by the involved root is relatively less occu- cross-sectional area of the multifidus muscle and weight pied in the plane, muscle atrophy at the lesion level or height of subjects in this study; however, it was re- may not be significant compared with that below the ported that the weight of patients is strongly related to lesion level. the cross-sectional area of lumbosacral paraspinal mu- Another possible explanation for muscle atrophy be- scles.24 We found that the relative values, such as the low the lesion level is the multiple innervation of one ratio of the cross-sectional area of cervical multifidus multifidus muscle. Hayashi et al. found that some multi- muscles in the involved side to that in the uninvolved fidus muscles innervated by avulsed roots did not dis- side were useful in revealing patients with cervical rad- play abnormal enhancement,6 and Wu et al. reported iculopathy instead of absolute values; therefore, pa- on polysegmental innervated lumbar multifidus muscles tients’ weight or height would not influence the results by electrodiagnosis;21 however, there has been no evi- of this study. We could not find any relationship be- dence of multiple innervation of the cervical multifidus tween symptom duration and cervical multifidus muscle muscle until now. atrophy; however, this finding is not clear because the In this study, the ratio of the cross-sectional area of number of cases in this study was small and some in- the multifidus muscle of the involved side to that of vestigators found this relationship in patients with uni- the uninvolved side is thought to be a useful parame- lateral low back pain.19 ter for differentiation of patients with cervical radicul- In this study, we measured the cross-sectional area opathy from other patients and controls; however, be- of cervical multifidus muscles in patients with cervical cause the incidence of abnormal cases was only about disc herniation or radiculopathy, and found that cervical 60%, more patients with disc herniation and radiculop- multifidus muscle atrophy was related at the lesion lev- athy would be needed in order to delineate the rela- el in patients with cervical radiculopathy, but not in tionship between cervical radiculopathy and multifidus patients with cervical disc herniation only. However, to muscle atrophy. reveal the mechanisms between muscle atrophy and The limitation of this study is that the number of radiculopathy in the cervical region more clearly, quan- patients was small and the age of patients with cer- tification or detailed classification of disc lesions and vical radiculopathy was older than that of the patient neck pain would be needed in further study. group and controls. Abnormal spontaneous activities in needle electromyography are detected only in severe cases with root lesions that lead to motor nerve de- nervation and concomitant denervated muscles, and not

749 Sang Han Chae, et al.

CONCLUSION WW. Fatty infiltration in the cervical extensor muscles in persistent whiplash-associated disorders: a magnetic In this study, asymmetric multifidus atrophy was seen resonance imaging analysis. Spine 2006; 31: E847-855 8)Elliott J, Jull G, Noteboom JT, Galloway G. MRI study of in patients with cervical disc herniation and radi- the cross-sectional area for the cervical extensor muscula- culopathy. Cervical MRI and analysis software that can ture in patients with persistent whiplash associated dis- separate fat infiltration from total CSA of multifidus orders (WAD). Man Ther 2008; 13: 258-265 muscles were useful for delineation of this finding, and 9) Fernandez-de-Las-Penas C, Bueno A, Ferrando J, Elliott JM, the ratio of pure muscle CSA between involved and un- Cuadrado ML, Pareja JA. Magnetic resonance imaging study of the morphometry of cervical extensor muscles in chronic involved sides might be a useful parameter for differ- tension-type headache. Cephalalgia 2007; 27: 355-362 entiation of patients with unilateral cervical radiculop- 10) Hyun JK, Lee JY, Lee SJ, Jeon JY. Asymmetric atrophy of athy from patients without radiculopathy. There was no multifidus muscle in patients with unilateral lumbosacral relationship between the cervical level of disc hernia- radiculopathy. Spine 2007; 32: E598-602 tion and multifidus muscle atrophy in patients with disc 11)Bogduk N, Wilson AS, Tynan W. The human lumbar herniation only; however, muscle atrophy was predom- dorsal rami. J Anat 1982; 134: 383-397 12)Kim BJ, Date ES, Derby R, Lee SH, Seo KS, Oh KJ, Kim inantly found below the level of cervical radiculopathy. MJ. Electromyographic technique for lumbar multifidus ex- Further study is needed to delineate more clearly the amination: comparison of previous techniques used to mechanism of multifidus muscle atrophy in patients with localize the multifidus. Arch Phys Med Rehabil 2005; 86: cervical disc herniation or radiculopathy. 1325-1329 13) Fernandez-de-las-Penas C, Albert-Sanchis JC, Buil M, Benitez JC, Alburquerque-Sendin F. Cross-sectional area of cervical multifidus muscle in females with chronic bilateral neck ACKNOWLEDGEMENTS pain compared to controls. J Orthop Sports Phys Ther 2008; 38: 175-180 The present research was supported by a research 14)Rubinstein SM, van Tulder M. A best-evidence review of fund from Dankook University in 2008. diagnostic procedures for neck and low-back pain. Best Pract Res Clin Rheumatol 2008; 22: 471-482 15) Campbell WW, Vasconcelos O, Laine FJ. Focal atrophy of the multifidus muscle in lumbosacral radiculopathy. Muscle REFERENCES Nerve 1998; 21: 1350-1353 16) Yoshihara K, Shirai Y, Nakayama Y, Uesaka S. Histochemical 1) Cote P, Cassidy JD, Carroll L. The Saskatchewan Health changes in the multifidus muscle in patients with lumbar and Back Pain Survey. The prevalence of neck pain and intervertebral disc herniation. Spine 2001; 26: 622-626 related disability in Saskatchewan adults. Spine 1998; 23: 17) Zhao WP, Kawaguchi Y, Matsui H, Kanamori M, Kimura T. 1689-1698 Histochemistry and morphology of the multifidus muscle 2) Ylinen J, Takala EP, Nykanen M, Hakkinen A, Malkia E, in lumbar disc herniation: comparative study between Pohjolainen T, Karppi SL, Kautiainen H, Airaksinen O. diseased and normal sides. Spine 2000; 25: 2191-2199 Active neck muscle training in the treatment of chronic 18)Hides J, Gilmore C, Stanton W, Bohlscheid E. Multifidus neck pain in women: a randomized controlled trial. JAMA size and symmetry among chronic LBP and healthy asymp- 2003; 289: 2509-2516 tomatic subjects. Man Ther 2008; 13: 43-49 3)Jordan A, Mehlsen J, Ostergaard K. A comparison of 19)Barker KL, Shamley DR, Jackson D. Changes in the physical characteristics between patients seeking treatment cross-sectional area of multifidus and psoas in patients for neck pain and age-matched healthy people. J Mani- with unilateral back pain: the relationship to pain and pulative Physiol Ther 1997; 20: 468-475 disability. Spine 2004; 29: E515-519 4) Rao R. Neck pain, cervical radiculopathy, and cervical 20) Zhang J, Tsuzuki N, Hirabayashi S, Saiki K, Fujita K. myelopathy: pathophysiology, natural history, and clinical Surgical anatomy of the nerves and muscles in the pos- evaluation. J Bone Joint Surg Am 2002; 84-A: 1872-1881 terior cervical spine: a guide for avoiding inadvertent 5) Panjabi MM, Cholewicki J, Nibu K, Grauer J, Babat LB, nerve injuries during the posterior approach. Spine 2003; Dvorak J. Critical load of the human cervical spine: an in 28: 1379-1384 vitro experimental study. Clin Biomech 1998; 13: 11-17 21)Wu PB, Date ES, Kingery WS. The lumbar multifidus 6)Hayashi N, Masumoto T, Abe O, Aoki S, Ohtomo K, Tajiri muscle in polysegmentally innervated. Electromyogr Clin Y. Accuracy of abnormal paraspinal muscle findings on Neurophysiol 2000; 40: 483-485 contrast-enhanced MR images as indirect signs of unila- 22) Fisher MA. Electrophysiology of radiculopathies. Clin teral cervical root-avulsion injury. Radiology 2002; 223: Neurophysiol 2002; 113: 317-335 397-402 23)Gilad R, Dabby R, Boaz M, Sadeh M. Cervical paraspinal 7) Elliott J, Jull G, Noteboom JT, Darnell R, Galloway G, Gibbon electromyography: normal values in 100 control subjects. J

750 Cervical Multifidus Muscle Atrophy in Unilateral Cervical Radiculopathy

Clin Neurophysiol 2006; 23: 573-576 with chronic low back pain. Br J Rheumatol 1992; 31: 24)Cooper RG, St Clair Forbes W, Jayson MI. Radiographic 389-394 demonstration of paraspinal muscle wasting in patients

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