Extension of Levator Ani Muscle Injury and Prolapse Exacerbation on Second Birth

第二胎时提肛肌损伤扩大和脱垂加重

• 批准号: 8549846
• 负责人: JOHN O.L. DELANCEY
• 金额: $ 25.4万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8549846
• 关键词: Address; Affect; Birth; Body Image; Cohort Studies; Consent; Data; Databases; Discipline of obstetrics; Elderly; Event; Exhibits; Fiber; First Births; Forcep; Funding; Future; Genital system; Goals; Head circumference; High Risk Woman; High birth weight infant; Injury; Instruction; Intervention; Intestines; Intra-abdominal; Learning; Life; Magnetic Resonance Imaging; Maternal Age; Measures; Minor; Muscle; Muscle Fibers; Operative Surgical Procedures; Organ; Pathway interactions; Pelvic floor dysfunction; Pelvic floor structure; Pelvis; Positioning Attribute; Prevention strategy; Ptosis; Public Health; Quality of life; Questionnaires; Recurrence; Relative Risks; Research; Risk; Risk Factors; Sampling; Selection Criteria; Self Efficacy; Severities; Speculums; Staging; Stress Tests; Structure; Symptoms; Testing; Time; Trauma; Urethra; Urinary Incontinence; Vaginal delivery procedure; Woman; Women' s Group; abdominal pressure; case finding; child bearing; clinically relevant; cohort; design; diaries; evidence base; expectation; experience; high risk; instrument; levator ani muscle; novel; parity; pressure; prevent; prospective; reproductive; sphincter ani muscle structure

We do not know why some women who give birth vaginally sustain an extensive major levator ani (LA) muscle tear. Nor do we know why 1 in 10 women suffer pelvic organ prolapse. In 2003, we began testing thishypothesis in a sample of women predisposed for LA injury because all had obstetric events associated with LA trauma (e.g. forceps, anal sphincter tear). With these high risk women, the tear was still only partial, less than 50% muscle fiber loss. Since it is major LA tear that is associated with prolapse when studied in multipara later in life, we need to learn about LA tear progression from first to second birth and how this contributes to prolapse later in life. We hypothesize that 1) exposure again to vaginal birth after an initial LA partial tear places a woman at high risk for more extensive LA tear, that 2) extension in LA tear is associated with increased pelvic organ descent, and this is because 3) the LA becomes unsupportive when it is no longer tethered to its origin. We aim to test these hypotheses in a highly efficient prospective cohort design. About 45% of our previously established cohort of first-birth women showed partial LA tear when evaluated by MRI. and the other half exhibited no evidence of tear despite also having obstetric risk factors for LA tear on first birth. We will study all of the women again to detennine if partial tear determines higher risk for extensive injury and increased prolapse when they birth again. All of the women in this established cohort have consented to further contact. We plan to evaluate those who have given birth vaginally a second time, comparing MRI data post first birth versus post second birth to quantify change in LA tear status, change in descent of the pelvic organs, and the relationship between the two. The degree of LA tear will be measured using the redesigned and novel instrumented speculum that eliminates crosstalk from intra-abdominal pressure during volitional contraction. Organ descent will be measured by comparing common organ position in both subject MRIs. This project has high impact through three independent pathways to clinical relevance. It will: 1) close the time-gap between the initial injury (first birth) and later life pronounced prolapse symptoms by demonstrating that injury extension and symptom progression are predicted by partial tear at first birth, 2) begin to shift the current paradigm of elective Cesarean for all to prevent LA injury to data-based selection criteria, and 3) pave the way for new interventions targeted to those women most at risk, those who give birth again after an initial partial LA tear on first birth.

我们不知道为什么有些阴道分娩的妇女会出现广泛的肛提肌（LA）撕裂。我们也不知道为什么十分之一的女性会遭受盆腔器官脱垂。2003年，我们开始在一组易患左心房损伤的妇女样本中检验这一假说，因为所有妇女都有与左心房损伤相关的产科事件（如产钳、肛门括约肌撕裂）。对于这些高危女性，撕裂仍然只是部分的， 超过50%的肌肉纤维流失由于在经产妇中研究时，主要LA撕裂与以后生活中的脱垂相关，因此我们需要了解从第一胎到第二胎的LA撕裂进展以及这如何有助于以后生活中的脱垂。我们假设：1）在最初的LA部分撕裂后再次暴露于阴道分娩使女性处于更广泛的LA撕裂的高风险中，2）LA撕裂的扩展与盆腔器官下降增加相关，这是因为3）当LA不支持时，LA变得不支持。 更长时间地束缚在它的起源上。我们的目标是在一个高效的前瞻性队列设计中检验这些假设。 在我们之前建立的第一胎女性队列中，约45%的患者在MRI评估时显示部分LA撕裂。而另一半则没有表现出撕裂的迹象，尽管在第一次分娩时也有LA撕裂的产科危险因素。我们将再次研究所有的妇女，以确定部分撕裂是否决定了再次分娩时大面积损伤和脱垂增加的风险。在这个既定队列中的所有女性都同意进一步接触。我们计划对那些第二次阴道分娩的人进行评估， 比较第一胎与第二胎后的MRI数据，以量化LA撕裂状态的变化、盆腔器官下降的变化以及两者之间的关系。将使用重新设计的新型仪器化窥器测量LA撕裂程度，该仪器消除了自主收缩期间腹内压的串扰。将通过比较两种受试者MRI中的共同器官位置来测量器官下降。该项目通过三个独立的临床相关性途径产生了很大的影响。 它将：（1）缩短初次受伤与（第一次分娩）和以后的生活中明显的脱垂症状，通过证明损伤扩展和症状进展是由第一次分娩时的部分撕裂预测的，2）开始将目前所有预防LA损伤的选择性剖腹产的范例转变为基于数据的选择标准，和3）为针对那些风险最高的妇女的新干预措施铺平道路，那些谁给 在第一次分娩时最初的部分LA撕裂后再次分娩。