Apical Ligament and Levator Muscle Interactions in Pelvic Organ Prolapse

阴道分娩使妇女发生脱垂的风险增加8倍，这种情况每年导致20万例手术，10年后再手术率高达25%。脱垂的两个主要原因是：1）宫颈和阴道上部下降（顶端下降），涉及主韧带/子宫骶骨韧带，2）阴道分娩期间提肛肌的神经肌肉损伤。 这些因素之间的关系是未知的。我们研究的总体目标是发现肌肉和韧带失效相互作用产生脱垂的基本机制。我们的理论工作提出了一个工作假设，即提肛肌损伤导致尿生殖道裂孔开放，并导致阴道壁暴露于向下拉顶支撑的压差。 缺乏有关韧带刚度的数据，防止定量了解这些关系。我们将招募并测试50名无症状志愿者和50名盆腔器官脱垂妇女，以实现以下目标。 目标1将使用一种新的伺服致动器装置来测量体内韧带力-位移行为（“刚度”），以确定不同韧带特性在脱垂中的作用。 目的2将进行静态和动态MRI图像和临床骨盆底测量，以确定a）肌肉损伤B）韧带特性对心尖下降的相对贡献。 目标3将创建主韧带和子宫骶骨韧带的受试者特定3D模型，该模型将用于确定心尖下降时主韧带和子宫骶骨伸长率的测量差异。 这项研究的结果将提供数据，可以导致临床相关的测试，例如，确定哪些患者需要手术来支持顶点。它还将提供急需的数据，验证关于韧带支持和肌肉损伤之间相互作用的整体疾病模型。这项研究将有助于制定改善预防和治疗选择的策略，并更好地了解为什么出生时的肌肉损伤会导致日后的脱垂。

Vaginal birth confers an 8-fold increase in the risk for a woman developing prolapse, a condition that results in 200,000 operations per year and carries up to a 25% reoperation rate at 10 years. Two primary causes for prolapse have emerged: 1) descent of the cervix and upper vagina (apical descent) involving the cardinal/uterosacral ligaments, and 2) neuromuscular damage to the levator ani muscles during vaginal birth. The relationship between these factors is unknown. It is the overall goal of our research to discover the basic mechanism whereby muscle and ligament failure interact producing prolapse. Our theoretical work suggests the working hypothesis that levator damage leads to opening of the levator urogenital hiatus and results in exposure of the vaginal wall to a pressure differential that pulls downward on the apical supports. Lack of data concerning ligament stiffness prevents a quantitative understanding of these relationships. We will recruit and test 50 asymptomatic volunteers and 50 women with pelvic organ prolapse to accomplish the following aims. Aim 1 will use a new servoactuator device to measure the in vivo ligament force-displacement behavior ("stiffness") to determine the role of different ligament properties in prolapse. Aim 2 will make static and dynamic MRI images and clinical pelvic floor measurements to establish the relative contribution to apical descent by a) muscle impairment b) ligament properties. Aim 3 will create subject-specific 3D models of the cardinal and uterosacral ligaments, which will be used to and determine the measurement differences in cardinal and uterosacral elongation in apical descent. The results of this study will provide data that can lead to clinically relevant tests to, for example, identify which patients need an operation to support the apex. It will also provide the much needed data, validating an overall disease model concerning interactions between ligament support and muscle damage. This research will be helpful in developing strategies for improved prevention and treatment selection and a better understanding of why muscle damage at birth causes prolapse later in life.