The Quantitative Study Of Biomechanical Properties Of Thoracolumbar Fascia By Shear Wave Elastography

Objective:1.To examine the intra and inter-operator reliability of shear wave elastography(SWE)device in quantifying stiffness of thoracolumbar fascia(TLF)and the device’s feasibility to examine stiffness of the TLF during different postures.2.To use SWE to quantify the relationship between stiffness and different body postures of TLF in healthy young people,and to analyze the effect of body postures on the biomechanics of TLF.3.To study the changes of TLF and trapezius stiffness using SWE in healthy male subjects under different body postures and to understand the effect of posture on lumbar back and the relationship stiffness between TLF and trapezius muscle.Methods:1.Twenty healthy young male subjects were recruited in the study.In the first measurement,operator A and operator B performed the same examination on the TLF of the same subject.The subjects were in the sitting posture,and the measurement positions were L2-3 and L3-4.Five days after the first measurement,operator A had made a second measurement of the same subject.Moreover,in the first measurement,operator A quantified the stiffness of the thoracolumbar fascia for the subjects at sitting-forward 600.2.Twenty healthy young male subjects were recruited in the study.All subjects were ultrasonically examined by the same investigator using SWE and were asked to perform seven static postures(rest,sitting,sitting-forward 30°,sitting-forward 60°,standing,standing-forward 30°,standing-forward 60°).3.Twenty healthy young male subjects were recruited in the study.The researchers used SWE to measure the hardness of TLF(L1-2,L3-4)and trapezius muscle(T5-6,T7-8,T9-10,T11-12)in different posture(sitting,sitting-forward30° and sitting-forward60°).Measurements were taken three times for each posture.Results:1.The intra-operator(ICC=0.860-0.938)and inter-operator(ICC=0.904-0.944)reliabilities for measuring the shear modulus of the TLF with the upper body forward 0° were rated as both excellent,and the MDC was 4.71 kPa.The TLF shear modulus of upper body forward 60°was increased 45.5%(L2-3)and 55.0%(L3-4)than that of upper body forward2.The TLF stiffness was significantly different among different postures(P<0.001),and the TLF stiffness at L2-3 was always less than that at L3-4(P<0.001).As the forward tilt increased from 0°to 60°,the TLF stiffness increased in sitting and standing postures by 54.01%and 192.84%.In the neutral postures,the TLF stiffness in standing and sitting postures was 66.98%and 165.48%higher than that in rest posture.3.Compared with sitting position,the extremely significantly increased in stiffness of the TLF(L3-4,L1-2)and trapezius muscle(T11-12)with increasing ante version angle(P<0.001).The stiffness of trapezius muscle(T7-8,T9-10)increased significantly at sittingforward30°(P<0.05),and extremely significantly increased at sitting-forward60°(P<0.001);The stiffness of trapezius muscle(T5-6)did not increased significantly at sittingforward30°(P>0.05),but extremely significantly increased at sitting-forward60°(P<0.001);There was a strong correlation between the changes of stiffness of all measurement points and the changes of L3-4 of TLF(r>0.8).Conclusion:1.The SWE has excellent the intra and inter-operator reliability in evaluating TLF stiffness of healthy young men.And,this technique can detect the change of TLF between sitting forward 0°and sitting-forward 60°.Therefore,the SWE is a dependable tool to quantify the shear modulus of TLF and monitor its dynamic changes,which provides the possibility for further studies the dynamic changes of TLF.2.The elastic properties of TLF play an important role in maintaining body static posture,it has the rule that the greater the anteversion angle,the greater the hardness of TLF,and and the TLF is more rigid near the sacral end than near the cranial end.In addition,the higher stifness of TLF in forward tilt and sitting postures,which indicated that poor posture and sedentary may be one of the potential factors causing LBP.These results preliminarily explored the relationship between human posture and TLF elasticity,and revealed the causes of posture induced LBP from the perspective of TLF stiffness,which provided a useful reference for the prevention and treatment of LBP.3.The results showed that there was a very significant continuity in hardness between TLF and trapezius muscle,and the sitting forward position could significantly increase the stiffness of the TLF,and then affect the stiffness of the trapezius muscle.This provides important guidance for us to understand the influence range of LBP and the biomechanical properties of myofascial network centered on TLF.