The changes in degree of nerve compression on magnetic resonance imaging in patients suffering from cervical disc herniation treated with cervical traction collar in combination with conservative treatment – Do Danh Thang

Journal of military pharmaco-medicine n 0 8-2018 154 THE CHANGES IN DEGREE OF NERVE COMPRESSION ON MAGNETIC RESONANCE IMAGING IN PATIENTS SUFFERING FROM CERVICAL DISC HERNIATION TREATED WITH CERVICAL TRACTION COLLAR IN COMBINATION WITH CONSERVATIVE TREATMENT Do Danh Thang1; Nguyen Van Chuong2; Nhu Dinh Son2 SUMMARY Objectives: To study the changes in degree of nerve compression on MRI in patients suffering from cervical disc herniation treated with cervical traction collar in combination with conservative treatment. Subjects and methods: A prospective, cross-sectional study with control group was conducted on 99 patients, of which 54 patients enrolled in the study group and 45 patients in the control group. Results: - After 2 weeks of treatment: The average anteroposterior compression ratio increased (p = 0.003) while the average degree of compression decreased (p = 0.007) in comparison with pre- treatment. There was no difference between treatment group and the control one after two weeks of treatment in terms of MRI results - After 6 months of treatment: The degree of compression decreased, while Torg-ratio and anteroposterior increased compared to pre-treatment. These changes were statistically significant, except for the change in SSI. Conclusion: The treatment of cervical disc herniation by cervical traction collar in combination with conservative treatment proved to be effective in decreasing the degree of nerve compression, which was shown by the results of MRI. * Keywords: Cervical disc herniation; Nerve compression; MRI; Cervical traction collar; Conservative treatment. INTRODUCTION Spinal disc herniation is a fairly common disease, with the most incident one is lumbar disc herniation, followed by cervical disc herniation [4, 6]. Cervical spondylotic myelopathy is a common degenerative disease associated with spinal stenosis in the elderly. Spinal stenosis can be caused by a variety of factors, including disc herniation or swelling, osteophytes and ossification of the posterior longitudinal ligament. Those factors that compress the spinal cord can cause spinal cord ischemia, leading to changes in the histopathology of the spinal cord [2]. There are several 1. 110 Military Hospital 2. 103 Military Hospital Corresponding author: Đỗ Danh Thắng (dodanhthang@gmail.com) Date received: 20/07/2018 Date accepted: 20/09/2018 Journal of military pharmaco-medicine n 0 8-2018 155 methods of evaluating the degree of spinal stenosis as well as disc herniation [3], but MRI is currently the most common diagnostic imaging method to accurately measure spinal stenosis. Not only does it reveal the width and length of the spinal canal, but it also demonstrates in details the spinal cord, intervertebral disc, osteophytes, and ligaments, which are potential causes of spinal stenosis [1, 2]. Therefore, we conducted the study with the aim: To study the changes in degree of nerve compression on Magnetic Resonance Imaging in patients suffering from cervical disc herniation treated with cervical traction collar in combination with conservative treatment. SUBJECTS AND METHODS 1. Subjects. 99 patients with cervical disc herniation diagnosed by MRI were included. These patients were treated at 103 Military Hospital from December 2012 to December 2015. * Selection criteria of patients with cervical disc herniation: - Clinical: + related-cervical spine syndrome. + at least one of the syndromes: . Nerve root compression . Cervical cord compression . Autonomic dysfunction and vertebrobasilar insufficiency. - Subclinical: MRI of cervical spine with results of disc herniation. * Exclusion criteria: - Patients had comorbidity between cervical disc herniation and other diseases of the spinal cord including spondyloarthritis, Pott disease, tumors, infections, amyotrophic lateral sclerosis and disseminated sclerosis. - Patients had cervical spinal surgeries due to disc herniation and injuries. - Patients had peripheral neuropathy - Patients had diabetes and alcoholism. - Patients under the age of 18 or over the age of 70. * Randomly divided the patients into two groups: - Group I (54 patients): The treatment group, which was treated with cervical traction collar in combination with conservative treatment regimen. - Group II (45 patients): The control group, which was treated only with conservative treatment regimen. 2. Method. - Stretching method: Use CS300 neck spine extension, 30 minutes on time and 3 times a day. - A cross-sectional descriptive study with comparative control group. - The MRI of cervical spine was performed on the system of MAGNETOM ESSENZA 1.5 TESLA; Siemens - Germany, in the Department of Diagnostic Imaging, 103 Military Hospital. Journal of military pharmaco-medicine n 0 8-2018 156 - Indicators included: + Torg-Ratio = Sagittal diameter of spinal canal Diameter of the vertebral body + Anteroposterior compression ratio (APCR): APCR = Anteroposterior diameter of the cord x 100% Transverse diameter of the cord + Segmental stenotic index: SSI = The diameter of the narrowest spinal canal The diameter of the widest spinal canal in the same vertebra + The degree of nerve compression had 4 levels and were called degree 1; degree 2; degree 3; degree 4 according to Nguyen Van Chuong - Data was analysed by SPSS software version 20.0. RESULTS Table 1: The MRI results of diameter (mm) of spinal canal and cord at the herniation before the treatment. Indicators Treatment group (n = 54) (X ± SD) Control group (n = 45) (X ± SD) p Sagittal diameter of spinal canal 7.36 ± 1.7 7.78 ± 2.03 p = 0.27 Diameter of the vertebral body 13.52 ± 1.17 13.76 ± 1.55 p = 0.39 Anteroposterior diameter of the cord 5.18 ±0.93 5.44 ± 0.94 p = 0.17 Transverse diameter of the cord 13.52 ± 1.16 13.12 ± 1.22 p = 0.08 The diameter of the widest spinal canal in the same vertebra 9.72 ± 1.48 9.69 ± 1.72 p = 0.93 There was no difference between the treatment and control group in terms of the diameter of spinal canal and cord. Table 2: The degree of herniation according to each evaluation method. Indicators Treatment group (n = 54) (X ± SD) Control group (n = 45) (X ± SD) p Torg-ratio 55.13 ± 14.23 58.02 ± 18.76 p = 0.39 APCR 38.70 ± 8.24 41.93 ± 8.46 p = 0.06 SSI 75.33 ± 10.59 79.51 ± 11.54 p = 0.06 Degree of nerve compression 2.87 ± 0.80 2.84 ± 0.93 p = 0.88 There was no difference between the treatment and control group in terms of the degree of herniation according to different methods of evaluation. Journal of military pharmaco-medicine n 0 8-2018 157 Table 3: The comparison of spinal stenosis after 2 weeks of the treatment group between 2 study groups. Indicators Treatment group (n = 54) (X ± SD) Control group (n = 45) (X ± SD) p Torg-ratio 54.8 ± 14.11 54.51 ± 16.85 0.93 APCR 39.16 ± 8.32 41.63 ± 9.14 0.2 SSI 74.86 ± 10.14 75.66 ± 9.89 0.72 Degree of nerve compression 2.78 ± 0.76 2.94 ± 0.87 0.36 There was no difference demonstrated by the MRI results between the treatment and control group after 2 weeks of treatment. Table 4: The comparison of MRI results on spinal stenosis of treatment group after 2 weeks of treatment Indicators Before treatment (X ± SD) After 2 weeks (X ± SD) p Torg-ratio (n = 50) 54.2 ± 14.07 54.8 ± 14.11 0.108 APCR (n = 50) 38.42 ± 8.18 39.16 ± 8.32 0.003 SSI (n = 50) 74.72 ± 10.65 74.86 ± 10.14 0.82 Degree of nerve compression (n = 50) 2.92 ± 0.78 2.78 ± 0.76 0.007 In the treatment group, after 2 weeks of treatment, the average APCR increased (p = 0.003) while the average degree of nerve compression decreased (p = 0.007). Table 5: The comparison of MRI results on spinal stenosis of the treatment group after 6 months of treatment. Indicators Before treatment (X ± SD) After 6 months (X ± SD) p Torg-ratio (n = 31) 53.58 ± 14.65 55.52 ± 15.38 0.005 APCR (n = 31) 37.0 ± 8.71 39.39 ± 8.79 0.001 SSI (n = 31) 71.81 ± 10.84 73.39 ± 10.47 0.06 Degree of nerve compression (n = 31) 2.87 ± 0.76 2.48 ± 0.77 0.001 In the treatment group, after 6 months of treatment, the average degree of nerve compression decreased, while Torg-ratio and APCR increased. All the changes were statistically significant, except for the SSI. Journal of military pharmaco-medicine n 0 8-2018 158 DISCUSSION Previous studies have described a number of methods of assessing the degree of cervical spinal stenosis. While many studies in the past conducted X-ray imaging method, the MRI has recently become the most common diagnostic imaging one to accurately measure the spinal stenosis. Not only does the MRI reveal the width and length of the spinal canal but it also demonstrates in details the spinal cord, intervertebral disc, osteophytes, and ligaments, which are potential causes of spinal stenosis [5]. In this study, we assessed the degree of nerve compression based on 4 indices: - Torg-ratio: Based on two measures: Sagittal diameter of spinal canal/diameter of the vertebral body. Our results indicated that the Torg-ratio of the treatment group before the treatment was 55.13 ± 14.23 while this figure for the control group was 58.02 ± 18.76. There was no difference between these groups prior to the treatment. When looking at the association with clinical characteristics, we found positive and quite strong correlation between the muscle strength score and Torg-ratio; and negative and moderate correlation between the cervical spine function score and Torg-ratio. - APCR: Defined by the 2 diameters of the cord (anteroposterior diameter/transverse diameter). Our pre-treatment results showed the APCR of the treatment and control group was 38.70 ± 8.24 and 41.93 ± 8.46, respectively. There was no difference between the two groups. When looking at the association with clinical characteristics, we found negative and moderate correlation between the VAS score for pain and APCR (r = 0.39; p = 0.003); negative and moderate correlation between the cervical spinal function score and APCR; and positive and quite strong correlation between muscle strength score and APCR. - SSI: Defined by the ratio between two measures: The diameter of the narrowest and widest spinal canal in the same vertebra, which reflected the degree of spinal stenosis more accurately. Our pre-treatment results showed the SSI of the treatment and control group was 75.33 ± 10.59 and 79.51 ± 11.54, respectively. There was no difference between the two groups. When looking at the association with clinical characteristics, we found negative and moderate correlation between the VAS score for pain and SSI; negative and moderate correlation between the cervical spine function score and SSI; and positive and moderate correlation between muscle strength score and SSI. Even though these three indicators were frequently used to assess the degree of spinal compression on MRI, each index had certain disadvantages: - Torg-ratio: By using two measures (sagittal diameter of spinal canal/posterior diameter of the same vertebral body). Allow us to evaluate based on the posterior diameter (central disc herniation). It is not suitable for those cases of median nerve root compression (lateral disc herniation) although this is the most common form of disc herniation. Journal of military pharmaco-medicine n 0 8-2018 159 - APCR is defined by the 2 diameters of the cord (anteroposterior diameter/transverse diameter). This index can be affected mainly due to the intrinsic variability of spinal cord (myeloma, syringomyelia, myelitis, cord swelling, etc.) and many other external factors (posterior longitudinal ligament, vertebra, etc.). In addition, the majority of disc herniation is lateral, thus the intervertebral disc does not directly compress the upper diameters of the spinal cord. Therefore, in the course of follow-up, there exists a discrepancy between clinical and subclinical remission. - SSI: is defined by the ratio between two measures: The diameter of the narrowest and widest spinal canal in the same vertebra. However, in several cases, the narrowest part of spinal canal is not caused by disc compression but other factors such as: the swelling and hyperplasia of vertebra and ligament system, etc. Thus, if this indicator is used, its results are sometimes inaccurate. As a result, in this study, we further determined the degree of nerve compression proposed by Nguyen Van Chuong. “The degree of nerve compression” was determined by the MRI cross-sectional image of the vertebra, at the maximal level of compression of the intervertebral disc on the spinal cord. “The degree of nerve compression” had 4 levels, called degree 1; degree 2; degree 3; degree 4 according to the number on the picture. The severity also increased in accordance with the order of degree. The results prior to the treatment indicated that “the average degree of nerve compression” was 2.87 ± 0.80 in the treatment group and 2.84 ± 0.93 in the control group, which implied no difference between these two groups. However, in the comparative analysis, we found no association between several clinical characteristics and the degree of disc compression. The MRI results after two weeks of treatment suggested that the average APCR increased (p = 0.003) while the average degree of compression decreased (p = 0.007) in comparison with the results before the treatment. Nevertheless, there was no difference between the two groups after two weeks of treatment in terms of MRI results. After six months of treatment, the Torg-ratio and APCR increased, while the degree of compression decreased compared to the results before the treatment. These changes were statistically significant with p < 0.05. The SSI after two weeks and six months of treatment increased and it had no statistical significance. CONCLUSION The treatment of cervical disc herniation by cervical traction collar in combination with conservative treatment proved to be effective in decreasing the degree of nerve compression, which was shown by the results of MRI. REFERENCE 1. Nguyen Thi Anh Hong. Cervical spinal stenosis: The value of MRI based on 300 cases. 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