Difference of cervical and shoulder muscle performance and its correlation with pain and body mass index in pa-tients with chronic neck pain

SHEN Xingxing; XIONG Yuling; CHEN Weijian; LI Congcong; LI Junyi; WANG Shuai; ZHANG Jiahao; XIANG Ruian; CHEN Jiahao; LIU Wengang; XU Xuemeng

doi:10.3969/j.issn.1006-9771.2023.12.006

Abstract：Objective To test the inter-tester reliability and test-retest reliability of MyotonPRO for evaluating neck and shoulder muscle performance parameters in patients with unilateral chronic neck pain,observe the difference of muscle performance between the healthy and affected sides of patients with chronic neck pain,and analyze the factors that cause the imbalance of muscle performance in patients with chronic neck pain. Methods From January to June,2023,32 patients with unilateral chronic neck pain in Guangdong Second Traditional Chinese Medicine Hospital were selected.Two testers used the same MyotonPRO equipment to measure the mus-cle tone,muscle hardness and muscle elasticity on both sides of the sternocleidomastoid muscle and the upper tra-pezius muscle in the relaxed position.Tester 1 repeated the measurement after an interval of 30 minutes,and Tes-ter 2 was measured within the time interval between the two measurements of Tester 1.The intraclass correlation coefficient(ICC),standard error of mean(SEM)and minimum detectable change(MDC)were calculated simul-taneously.The measurement results were plotted into Bland-Altman diagram and systematic bias analysis was performed.The difference in muscle characteristics between the affected side and the healthy side was compared.At the same time,the Visual Analogue Scale(VAS)score and body mass index(BMI)of the subjects were col-lected for correlation analysis. Results Except the sternocleidomastoid muscle elasticity of the affected side(ICC = 0.697),the inter-tester reliability of all other parameters was high to very high(ICC = 0.719 to 0.952,SEM = 0.04 to 6.53,MDC = 0.12 to 18.11).The test-retest reliability of all parameters was high(ICC = 0.883 to 0.981,SEM = 0.03 to 5.72,MDC = 0.09 to 15.84).Bland-Altman plot analysis showed that the scatter distribution was consistent.The muscle tone,muscle hardness and muscle elasticity of sternocleidomastoid muscle and upper trapezius muscle were higher on the af-fected side than on the healthy side(t>2.846,P<0.05).The asymmetry index of tension,hardness and elasticity of upper trapezius muscle and sternocleidomastoid muscle was significantly positively correlated with VAS score and BMI(r>0.385,P<0.05). Conclusion MyotonPRO has good inter-tester reliability and retest reliability in evaluating the muscle performance of both sides of patients with chronic neck pain.The muscle tone,muscle hardness and muscle elasticity of sterno-cleidomastoid muscle and upper trapezius muscle on the affected side were higher than on the healthy side,and the difference of muscle performance was positively correlated with pain and BMI.