Desenvolvimento de um protocolo de medida elastográfica do músculo multífido lombar: estudo de viabilidade aplicado em pessoas com lombalgia

Abstract

Muscular stiffness can occur in cases of low back pain, with changes in the elastic properties of the superficial and deep fibers of the multifidus muscle. Supersonic Shear Imaging (SSI) elastography has an advanced system for estimating tissue stiffness. This Thesis aimed to analyze the potential of SSI to identify the fiber stiffness of the multifidus and to propose an evaluation protocol for low back pain. Initially, to determine equipment configuration for in vivo analysis, tests were performed in homogeneous (gelatin) and non-homogeneous (beef) media. The elected configuration was the one for deep measurements because it provided less variability between the stiffness from layers evaluated. Thus, 26 asymptomatic and 13 symptomatic participants were evaluated, in prone and seated position, comparing the muscle layers, bilaterally. Reliability and transducer orientation (longitudinal and transverse) were tested in asymptomatic participants. Images acquired longitudinally obtained better reliability and less variability, showing differences between the stiffness of the layers, in both postures. Transversal images showed differences only in the seated posture. The group of symptomatic showed no differences between the layers in any posture. However, deep fibers stiffness of the multifidus were significantly higher in people with low back pain than in asymptomatic volunteers. None of the groups showed differences between the sides. Therefore, it is suggested to evaluate the stiffness of the multiple with SSI using specific configuration for deep regions, layers evaluated separately, in prone position.