The effect of some Yoga postures on the strain field in the Trapezius muscle of a patient suffering from Cervical Spondylosis

Transcription

1 Indian Journal of Biomechanics (ISSN : ) 2012, Volume 3, Issue 1-2, December 2012 (1-5) The effect of some Yoga postures on the strain field in the Trapezius muscle of a patient suffering from Cervical Spondylosis Rajneesh Singh, Sridhar Iyer and S. K. Roy Chowdhury* Indian Institute of Technology, Kharagpur * skrc@mech.iitkgp.ernet.in Abstract For patients suffering from Cervical Spondylosis among other discomforts the Trapezius muscle become tender and painful. Depending on the level of discomfort there exist pharmacological and surgical treatments to remedy such discomforts. In many cases physiotherapy is prescribed for such discomforts. Age old yoga postures are also believed to be effective means of reducing the discomfort level in such cases. The objective of the present work is to study the effect of one such yoga posture in reducing the pain in terms of the strain field in the Trapezius muscles. Digital Image Correlation (DIC) technique was used to obtain the strain field in the muscle of a healthy person and a patient suffering from Spondylosis. The effect of Yoga on the strain field, thus the pain experienced by the patient, was studied and it was observed that Gomukhasan is very effective in alleviating pain in case of Cervical Spondylosis. It is felt that such comparative studies using DIC can be useful physiotherapist and doctors to gauge the effectiveness of their treatment. Keywords : Cervical Spondylosis, Trapezius muscle, Yoga, Gomukhasan, DIC technique Introduction Cervical Spondylosis is a disorder in which there is abnormal wear on the cartilage and the cervical spine. This degenerative process irritates the nearby muscles, ligaments and nerves which can cause troublesome symptoms. Trapezius muscle is a large superficial muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae and laterally to the scapular spine. In Spondylosis this muscle becomes tender and painful. It is claimed that Yoga has proved to be far more efficacious than any other non intrusive method in alleviating pain in the Trapezius muscle. A patient experiences relief when the inter-vertebral spaces are widened. This can be done by pulling the Trapezius muscle and other related muscles downwards. Gomukhasan, Sarvangasana and Halasana are some of the Yoga postures which can help in the said process. Hitherto no quantitative study has been done on the effect of Yoga postures on a patient suffering from Spondylosis. Since strain is directly proportional to the pain experienced by the patient, a measurement of strain field in the Trapezius muscle would provide a picture of the pain level quantitatively. Very little literature is available on strain measurements in muscle because unlike in the case of bones methods, such as, X-ray Diffraction, Neutron Diffraction [1, 2] cannot be used. However analytical methods such as FEM [3-5] and FVM [6] have been used for obtaining strain fields theoretically. In the present study Digital Image Correlation (DIC) technique [7-13] was used to obtain strain field experimentally. Since DIC is a non contact process it gives an accurate picture of the strain field on a muscle without disturbing it. 1

2 2 Rajneesh Singh et al. / Indian Journal of Biomechanics (2012) 1-5 Digital Image Correlation The basic underlining theory used in the methods such as digital speckle correlation (DSCM) [6], electronic speckle photography [15] and many other methods [8,14] which have been extensively studied and referred to in numerous literatures is the same. These methods, like the digital image correlation (DIC) technique used here, use the grey Figure-2.Schematic drawing of Relative location of subimages of deformed and undeformed images Further an iterative approach is used to predict the DIC by maximizing the correlation coefficient. Figure-1. Typical Optical image acquisition system for 2-D DIC [7] scale values of the two images, i.e., the deformed and un-deformed images, to compute the field displacement and thus obtain strain field. Some of the salient features of DIC as a tool for measuring strain field are It is a non-contact method, thus can be used for measuring deformations in soft polymeric and bio materials. Whole field displacement and strain field is obtained. Micro and Nano scale strain can be obtained. When the undeformed subimage image A (with P and Q), undergoes deformation to B (with P* and Q*) there is corresponding change in the grey scale value, from to. These values are used to compute the correlation coefficient. The COF is given by: Calculation of strain field Consider points P and Q located at (x,y) and (x+,y+ y) respectively before deformation which move to P* and Q* after deformation as shown in figure-2. Now, can be obtained using the relation [7, 16, and 17] Similarly, and can be computed as Experimental Procedure and Analysis Upper Trapezius muscle was used as the substrate. The substrate was created by placing black dots over the surface after painting it white as shown in

3 Rajneesh Singh et al. / Indian Journal of Biomechanics (2012) Figure-3. Distribution of linear strain for a patient suffering from cervical Spondylosis at normal sitting position Figure-4. Distribution of linear strain in the Trapezius muscle of a human at normal sitting position Figure-5. Distribution of linear strain in the Trapezius muscle of a healthy worker at orientation of the neck towards right side Figure-6. Distribution of direct strain along Y axis and shear strain in XY plane in the Trapezius muscle of a healthy person at orientation of the neck towards right side

4 4 Rajneesh Singh et al. / Indian Journal of Biomechanics (2012) 1-5 Figure-7. Distribution of linear strain in the Trapezius muscle of person suffering from Cervical Spondylosis at orientation of the neck towards right side Figure-8. Distribution of lateral strain in a patient suffering from cervical Spondylosis while performing Gomukhasan figure-3. One fixed CCD camera is used to record the digital images of the test specimen surface before and after deformation Strain distribution in the Trapezius muscle of a healthy person at 30 o orientation of the neck towards right side is shown in Figure-5. The point of reference shifted μm along the x axis as observed from the image. Similarly displacements and thus the direct strain in Y axis and shear strain in XY plane were obtained. The maximum strain was in the range of.0172 μm. Distribution of shear strains in the Trapezius muscle of a healthy person at 30 o orientation of the neck towards right side is shown in Figure-6. The maximum strain in a person suffering from Spondylosis was also obtained in the same way and the strain field is shown in Figure-7. This was found to be in the range of.03μm which is roughly twice as much as that of a healthy person. Strain field was obtained while the patient performed Gomukhasan and this is shown in figure-8 It can be seen that the strain values obtained while performing Gomukhasan were significantly lower than the previous case and this demonstrates the positive impact of Yoga postures in relieving the pain experienced by the Cervical Spondylosis patient. Conclusion The present work establishes a methodology for measuring the strain field in the soft human muscles of a healthy person and a patient suffering from Spondylosis using a Digital Image Correlation.

5 Rajneesh Singh et al. / Indian Journal of Biomechanics (2012) The level of discomfort can be calibrated for the strain field and therefore the strain field obtained by DIC can be used for quantifying the pain or discomfort level. The strain field of a healthy person, a patient suffering from Spondylosis and of a patient suffering from Cervical Spondylosis while performing Gomukhasan were obtained using DIC technique. A comparison of strain levels clearly indicates that some Yoga postures can be greatly beneficial for a patient suffering from Cervical Spondylosis. The technique developed here can be used by physiotherapist and doctors to access the pain level of a patient and thus access the efficacy of the current treatment regimen and decide on a future course of treatment. References 1. Bacon, G. E., P. J. & Griffiths, R. K "The study of bones by neutron diffraction". Journal of Applied Crystallography 10, pp J.D. Almer & S.R. Stock 2005 "Internal strains and stresses measured in cortical bone via high-energy X-ray diffraction". Journal of Structural Biology 152, pp Thomas R Jenkyn et al "Finite element model of intramuscular pressure during isometric contraction of skeletal muscle", Phys. Med. Biol. 47, pp P. Meier and R. Blickhan FEM-Simulation of Skeletal Muscle: The Influence of Inertia during Activation and Deactivation. 5. A. Hung, K. Mithraratne, M. Sagar, and P. Hunter Multilayer Soft Tissue Continuum Model: Towards Realistic Simulation of Facial Expressions. World Academy of Science, Engineering and Technology, 6. Beynnon, J. G. Howe, M. H. Pope, R. J. Johnson, and B. C. Fleming 1992, The measurement of anterior eruciate ligament strain in vivo,b. International Orthopaedics. 16, Issue: 1, Publisher: Springer, pp. 1-12, 7. T.C. Chu, W.F. Ranson, M.A. Sutton and W.H. Peters "Applications of Digital Image-Correlation Techniques to Experimental Mechanics. Experimental Mechanics" 25, pp W. H. Peters, and W. F. Ranson "Digital imaging techniques in experimental stress analysis", Optical Engineering, pp Jinlong Chen, Ganmin Xia, Kebin Zhou, Guisuo Xia, Yuwen Qin "Two-step digital image correlation for micro-region measurement", Optics and Lasers in Engineering 43, pp Zhang D, Zhang X and Cheng G Compression strain measurement by digital speckle correction Exp. Mech. 39, pp Bing Pan, Kemao Qian, Huimin Xie and Anand Asundi Two-dimensional digital image correlation for in-plane displacement and strain measurement. 12. Chen D J, Chiang F P, Tan Y S and Don H S "Digital speckle-displacement measurement using a complex spectrum method" Appl. Opt. 32, pp Shih-Heng Tung, Chung-Huan Sui "Application of digital image correlation techniques in analyzing cracked cylindrical pipes". Sadhana 35, Part 5, pp Bay B K Texture correlation - A method for the measurement of detailed strain distributions within trabecular bon J. Orthop. Res 13, pp Sjodahl M and Benckert L R "Electronic speckle photography: analysis of an algorithm giving the displacement with sub-pixel accuracy" Appl. Opt. 32, pp Novozhilov, V. V., 1861 Theory of Elasticity, U.S. Dept. of Commerce Translation. 17. Fung, Y.C., 1965 Foundations of Solid Mechanics, Prentice Hall Inc., Englewood Cliffs, NJ.