Biomechanics of Birth-Related Injuries

出生相关伤害的生物力学

• 批准号: 8549844
• 负责人: JOHN O.L. DELANCEY
• 金额: $ 22.32万
• 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/8549844
• 关键词: 3-Dimensional; Address; Age-Years; Anterior; Bilateral; Biomechanics; Birth; Birth trauma; Cadaver; Computer Simulation; Data; Development; Elasticity; Elements; Ethics; Exercise; Failure; Female; Funding; Genital system; Head; Health; Histology; Human; Incontinence; Injury; Instruction; Intervention; Isometric Contraction; Knowledge; Lead; Length; Life; Link; Magnetic Resonance; Magnetic Resonance Imaging; Measurement; Measures; Membrane; Methods; Modeling; Morphology; Muscle; Outcome; Pattern; Pelvic Floor Muscle; Pelvic floor dysfunction; Pelvis; Pregnancy; Property; Ptosis; Research; Risk; Risk Factors; Running; Rupture; Scanning; Second Labor Stage; Shapes; Staging; Stereophotogrammetries; Stretching; Structure; Tensile Strength; Testing; Thigh structure; Time; Tissues; Ultrasonography; Vagina; Vaginal delivery procedure; Variant; Woman; Work; arm; base; cost; design; elastography; exhaustion; fetal; improved; insight; instrument; levator ani muscle; modifiable risk; pregnant; prevent; volunteer; women employment

Approximately 15% of women sustain pelvic muscle injuries during vaginal birth, demonstrable through magnetic resonance (MR) imaging. Our geometric model suggests the pelvic floor muscles stretch up to 3.3 times their original length during the second stage of birth. Based on MR imaging, histological, studies, and biomechanical modeling, when injury occurs, we hypothesize an initial rupture of the pubic attachment ofthe pubovisceral muscle (Type 1 injury), in some women followed by an avulsion of the pubic attachment of the arcus tendineus levator ani (Type 2 injury). We seek funds to characterize the variation of tissue in these injury zones and document their failure loads. AIM 1 will characterize the morphology and histology of pubovisceral and arcus tendineus tissues, bi-axial material properties where appropriate, and uniaxial failure properties in 30 cadavers. In 20 volunteers, we will use ultrasound elastography to characterize the effect of pregnancy on perineal body elasticity. AIM 2 will use Aim 1 data to refine a subject-specific, 3-D finite element viscohyperelastic biomechanical model of the second stage of labor from Station +2 on. We will test the above hypotheses with regard to the sequence of Type 1/Type 2 injuries, and run parametric studies to determine the biomechanical factors that increase or decrease the risk of Type 1 and Type 2 injuries. We will validate the model with stereophotogrammetric measurements of perineal descent in 10 laboring women. Since maternal exhaustion is a major risk for instrumented delivery and levator muscle injuries, in AIM 3 we will use a repeated measures design to quantify the outcomes in 40 healthy non-pregnant volunteers between 21 and 30 years of age to study the energetic cost of Valsalva pushing with and without (a) maximal arm and (b) arm and thigh muscle isometric contractions. 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.

大约 15% 的女性在阴道分娩期间遭受盆腔肌肉损伤，这可以通过磁共振 (MR) 成像来证明。我们的几何模型表明，在出生的第二阶段，盆底肌肉会拉伸至原始长度的 3.3 倍。基于 MR 成像、组织学、研究和生物力学模型，当损伤发生时，我们假设一些女性的耻骨内脏肌耻骨附着物最初破裂（1 型损伤），随后腱弓耻骨附着物撕脱提肛肌（2 型损伤）。我们寻求资金来描述 这些损伤区域组织的变化并记录其失效载荷。 AIM 1 将表征 30 具尸体的耻骨内脏和腱弓组织的形态和组织学、双轴材料特性（如果适用）以及单轴失效特性。我们将在 20 名志愿者中使用超声弹性成像来表征妊娠对会阴身体弹性的影响。 AIM 2 将使用 Aim 1 数据来完善从 Station +2 开始的第二产程的特定主题 3D 有限元粘超弹性生物力学模型。我们将测试上述关于 1 型/2 型损伤顺序的假设，并进行参数研究以确定增加或降低 1 型和 2 型损伤风险的生物力学因素。我们将通过对 10 名产妇的会阴下降进行立体摄影测量来验证该模型。 由于产妇疲惫是器械助产和提上睑肌损伤的主要风险，因此在 AIM 3 中，我们将使用重复测量设计来量化 40 名 21 至 30 岁之间的健康非怀孕志愿者的结果，以研究 Valsalva 的能量消耗有和没有（a）最大手臂和（b）手臂和大腿肌肉等长收缩的推力。 这些观察将深入了解与最大伤害风险相关的因素，并应导致更好的方法来预防这些伤害。