Comparison of the Local Tissue Milieu in Normal muscle and Active and Latent Myo

肌筋膜疼痛综合征(MPS)是一种与局部疼痛和肌肉压痛相关的疾病，其特征是存在超敏结节，也称为肌筋膜触发点(MTrps)。MPS影响高达95%的慢性疼痛障碍患者，是专业疼痛管理中心患者的常见发现。然而，肌筋膜痛的病因和肌筋膜痛的病理生理学尚不清楚。 MTrP是骨骼肌束紧绷的明显僵硬结节--这是MPS的特征。虽然手指触诊被认为是诊断MTP的金标准，但它并不能1)提供客观、可靠和灵敏的诊断和治疗效果的方法；2)提供治疗前后组织特性的定量比较；3)客观区分活跃的MTP、潜伏的MTP和明显的正常组织；4)客观区分浅层和深层MTP；以及5)允许客观研究MTP的自然历史。 为了解决这些局限性，我们的团队正在利用诊断超声成像技术的新应用，如灰阶(2D超声)、振动超声弹性成像和多普勒，以成像MTrP及其周围肌肉以及含有MTrp的肌肉的局部微血管和血流特性。通过使用这些技术，我们的团队试图更好地了解活跃的MTrp、潜伏的MTrp和明显的正常组织的物理特性和血管环境。我们的目标还包括开发新的、高效且易于管理的弹性成像技术，以便使用现成的基于办公室的设备在门诊临床环境中提供骨骼肌粘弹性特性的定量表征。 超声弹性成像研究表明，与潜伏期MTrp和明显的正常组织相比，活动MTrp有更大的面积，因此MTrp可以按面积进行分类。多普勒频谱波形数据显示，这些活跃的MTrP部位附近的血管的搏动指数明显高于正常部位，这一发现可能有助于评估MPS的病史。振动超声弹性图显示，与正常组织相比，上斜方肌中的MTrp具有显著更高的剪切弹性系数(刚性测量)，而活动MTrp的剪切波速明显更高(与粘弹性有关)。这些结果表明，MTrp及其周围组织增加了组织的异质性。 我们的研究对肌筋膜痛的病理生理学有了更好的理解，并对临床护理有一定的指导意义。超声弹性成像技术可以很容易地转换到临床环境中，使用现成的办公室设备来定量表征骨骼肌的生物力学特性。此外，它还可以克服触诊和体检的主观性，并可以得出客观的临床结果衡量标准。我们相信，随着时间的推移和治疗前后对MTrp及其周围肌肉组织生物力学特性的纵向监测，可以更好地从机制上了解活动MTrps治疗(如干针疗法)后上斜方肌环境发生的变化。

Myofascial pain syndrome (MPS) is a condition associated with regional pain and muscle tenderness characterized by the presence of hypersensitive nodules, also called myofascial trigger points (MTrPs). MPS affects up to 95% of people with chronic pain disorders and is a common finding in patients in specialty pain management centers. However, the etiology of myofascial pain and the pathophysiology of MTrPs are unclear. MTrPs are palpable, stiff nodules in a taut band of skeletal muscle - a characteristic finding in MPS. Although digital palpation is considered the gold standard for diagnosis of MPS, it does not 1) provide an objective, reliable and sensitive method of diagnosis and measurement of treatment efficacy; 2) provide quantitative comparisons of the tissue properties before and after treatment; 3) objectively differentiate among active MTrPs, latent MTrPs, and palpably normal tissue; 4) objectively discriminate between superficial and deep MTrPs; and 5) permit objective study of the natural history of MTrPs. To address these limitations, our team is utilizing novel applications of diagnostic ultrasound imaging techniques, such as grayscale (2D Ultrasound), vibration sonoelastography, and Doppler, to image the MTrP and its surrounding muscle as well as the local microvasculature and blood flow properties of muscle harboring MTrPs. Through the use of these techniques, our team sought to better understand the physical properties and vascular environment of active MTrPs, latent MTrPs, and palpably normal tissue. Our objectives also included developing new, efficient, and easy to administer elastography techniques to provide quantitative characterization of viscoelastic properties of skeletal muscle in an outpatient clinical environment using off-the-shelf office-based equipment. The sonoelastography studies showed that active MTrPs had larger areas compared to latent MTrPs and palpably normal tissue and therefore MTrPs may be classified by area. Doppler spectral waveform data indicated that blood vessels near these active MTrP sites had a significantly higher pulsatility index compared to normal sites, a finding that may be useful in evaluating the history of MPS. Vibration sonoelastography demonstrated that MTrPs in upper trapezius had significantly higher shear modulus (measure of rigidity) and active MTrPs had significantly higher shear wave speeds (related to viscoelastic properties) when compared to palpably normal tissue. These results indicate that MTrPs and their surrounding tissue have increased tissue heterogeneity. Our research has yielded a better understanding of the pathophysiology of myofascial pain and has implications for clinical care. The sonoelastography techniques can be easily translated to the clinical setting using off the shelf office-based equipment to quantitatively characterize biomechanical properties of skeletal muscle. Furthermore, it can overcome the subjectivity of palpation and physical examination, and could lead to an objective clinical outcome measure. We believe that longitudinal monitoring of biomechanical properties of both MTrPs and the surrounding muscle tissue over time and before and after treatment can provide a better mechanistic understanding of the changes that occur in the environment of the upper trapezius following treatment for active MTrPs, such as dry needling therapy.