Quantitative Evaluation Of Mechanical Properties Of Neck Muscles In Subjects With And Without Nonspecific Neck Pain

Objective To evaluate differences of muscle biomechanical properties between nonspecific neck pain(NNP)group and healthy group by measuring the stiffness,elasticity of neck muscles and neck skin temperature;compare biomechanical properties of neck muscles before and after smart phone reading task between NNP group and healthy group.Methods 22 patients with NNP were included as NNP group,20 healthy people as control group.In the standardized laboratory,two groups of subjects were given the same task of using smartphone in the prescribed posture(smart phone model: OPPO R11;time: 30min;content: Reading novels).Before smart phone reading task,the biomechanical Properties(stiffness and elasticity)of bilateral sternocleidomastoid muscle,splenius capitis,upper trapezius muscle and scapular levator muscle were measured by Myoton PRO device,and the skin temperature of the back of neck region was measured by medical infrared thermal imager.After smartphone reading task of 30 min,the mechanical Properties(stiffness,elasticity)and neck skin temperature were measured again.Results(1)In NNP group,the VAS scores were positively correlated with the muscle stiffness of bilateral upper trapezius muscles and splenius capitis(r=0.55?0.92?0.71?0.74,P<0.01).The muscle stiffness of bilateral splenius capitis,scapular levator muscles and upper trapezius muscles in the NNP group were significantly higher than that in the control group(z=-4.0?-3.2?-3.5?-2.6?4.5?-4.9,P<0.05);The muscle elasticity of bilateral splenius capitis and scapular levator muscles in NNP group was lower than that in control group(t=4.2?7.3?3.2?4.2,P<0.05);There was no significant difference in neck skin temperature between NNP group and control group(P>0.05).(2)After smartphone reading task for 30min:in NNP group,the stiffness of bilateral splenius capitis,scapular levator muscles and right trapezius muscle were increased significantly(t=-2.5?-3.8?-4.9?-4.4?-4.8,P<0.05);The elasticity on bilateral splenius capitis decreased significantly(t=-3.1?2.5,P<0.05)in NNP group;There was no change in neck skin temperature in NNP group(P>0.05).In control group,the stiffness of right splenius capitis increased significantly(t=-6.7,P<0.05);There was no change in muscle elasticity of bilateral splenius capitis,scapular levator muscles,trapezius muscles and sternocleidomastoid muscles in the control group(P>0.05);There was no change in neck skin temperature in control group(P>0.05).The changes of muscle stiffness(difference d)of right splenius capitis,bilateral scapular levator muscles and left trapezius muscle in NNP group were different from those in control group(t = 2.7?2.8?2.3?2.2,P<0.05).The changes of muscle elasticity of bilateral splenius capitis,right scapular levator muscle,left trapezius muscle and left sternocleidomastoid muscle in the NNP group were significantly different from those in the control group(t = 6.1?8.5?4.6?3.7?3.1,P<0.05).Conclusion The stiffness of bilateral splenius capitis,scapular levator muscles and trapezius muscles in patient group were higher than that in the control group,while the muscle elasticity of bilateral splenius capitis and scapular levator muscles were smaller than that of control group.Muscle stiffness and elasticity can be used as objective evaluation indexes to identify NNP,however,further research is needed on how to apply this indexs to clinical practice.The changes of mechanical properties of neck muscles in patients with NNP were higher than those in the control group.Maybe the patterns of change in biomechanical properties of neck muscles are different between NNP group and control group.