BIOMECHANICS OF SIMULATED VAGINAL BIRTH

模拟阴道分娩的生物力学

• 批准号: 7715230
• 负责人: JAMES Anthony ASHTON-MILLER
• 金额: $ 22.45万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7715230
• 关键词: 3-Dimensional; Affect; Anesthetics; Anterior; Behavior; Biological Assay; Biomechanics; Birth; Caliber; Cephalopelvic Disproportions; Cesarean section; Condition; Dental crowns; Elastic Tissue; Elements; Episiotomy; Failure; Forcep; Goals; Head; Human; Injury; Isometric Exercise; Laws; Lead; Location; Measures; Mechanics; Methods; Minor; Modeling; Muscle; Muscle Contraction; Muscle strain; Nature; Paralysed; Patient currently pregnant; Pelvic Floor Muscle; Pelvic floor structure; Predisposition; Pregnancy; Pregnancy Tests; Pregnant Women; Property; Rate; Rattus; Recording of previous events; Relaxation; Research; Resistance; Risk; Rupture; Saimiri; Sampling; Second Labor Stage; Shapes; Simulate; Specimen; Speculums; Spinal; Staging; Standards of Weights and Measures; Stress; Stretching; Testing; Time; Tissues; Traction; Tube; Vagina; Vaginal delivery procedure; Validation; Weight; fetal; in vivo; insight; instrument; levator ani muscle; pressure; prevent; research study; size; soft tissue; sphincter ani muscle structure; volunteer

Biomechanics of Birth-Related Injuries The overall goal of this research is to better understand the mechanisms of maternal vaginal birthrelated injury at the end of the second stage of labor. The main factor affecting the resistance of the pelvic floor muscles to stretch as they resist the downward descent of the fetal head is their viscoleastic material properties. The effect of term pregnancy on these properties has never been documented, partly due to the difficulty of obtaining sample of undamaged human pelvic floor tissues during birth. In AIM 1, therefore, we will use equi-biaxial testing and stepwise stress relaxation assays to characterize the effect of term pregnancy on the constitutive law and mechanical behavior of mammalian pelvic floor tissues in rat and squirrel monkey. Uniaxial failure tests will also be conducted to determine the effect of pregnancy and test direction on the ultimate tensile stress in these tissues. In AIM 2.1 we will develop a subject-specific, 3-D finite element biomechanical model of the second stage of labor from Station +2 on with representations of the fetal head, five major pelvic floor muscles and related soft tissues, as well as the time-varying maternal expulsive force. In AIM 2.2 we will validate the model predictions by comparing them against the results of in vivo experiments in pregnant women. These involve the measured temporal displacement of a posterior weighted speculum at Csection, and the time course of the increase in vaginal diameter upon fetal head crowning. In AIM 2.3 we will investigate the effect of (a) fetal head orientation, (b) cephalopelvic disproportion, (c) maternal sub-pubic arch angle, (d) epidural, (e) forceps use, and (f) episiotomy on the magnitude, direction and location of maximum pelvic floor muscle tissue stress. The ratio of that stress to the ultimate tensile stress is taken as a measure of the risk of tissue injury. These observations will yield insights into the factors associated with the greatest risk for injury, and should lead to better methods of preventing these injuries.

与出生有关的生物力学 这项研究的总体目的是更好地了解母体阴道分娩的机制 第二阶段劳动结束时受伤。影响电阻的主要因素 骨盆底肌肉在抵抗胎头的下降时会伸展 材料特性。怀孕对这些特性的影响从未被记录过， 部分原因是在出生过程中很难获得未受损的人骨盆底组织样本。 因此，在AIM 1中，我们将使用等轴轴测试和逐步应力放松测定法 表征术语怀孕对本构法的影响和机械行为 大鼠和松鼠猴的哺乳动物骨盆底组织。也将进行单轴故障测试 确定妊娠和测试方向对这些组织中最终拉伸应力的影响。 在AIM 2.1中，我们将开发第二个主题的3-D有限元生物力学模型 站点+2的劳动阶段与胎头的表示形式，五个主要的骨盆底肌肉 和相关的软组织以及随时间变化的母体驱除力。在AIM 2.2中，我们将 通过将模型与孕妇体内实验的结果进行比较来验证模型预测 女性。这些涉及在剖腹时进行后加权镜的时间位移， 以及胎头冠冕时阴道直径增加的时间过程。 在AIM 2.3中，我们将研究（a）胎儿方向的效果，（b）头骨不成比例，（c） 孕妇亚管拱角，（d）硬膜外，（e）使用镊子和（f）（f）在大小上进行的（f） 最大骨盆底肌肉组织应力的方向和位置。这种压力与 最终的拉伸应力被视为衡量组织损伤风险的量度。这些观察结果将产生 洞悉与最大伤害风险相关的因素，并应带来更好的方法 防止这些伤害。