Department of Bioengineering, University of Pittsburgh, 3700 O'Hara Street, 406 Benedum Hall, Pittsburgh, PA, 15260, USA.
Department of Obstetrics, Gynecology & Reproductive Surgery, Magee-Womens Research Institute, University of Pittsburgh, Pittsburgh, PA, USA.
Ann Biomed Eng. 2023 Jul;51(7):1461-1470. doi: 10.1007/s10439-023-03150-z. Epub 2023 Jan 30.
Specific levator ani muscle imaging measures change with pregnancy and vaginal parity, though entire pelvic floor muscle complex (PFMC) shape variation related to pregnancy-induced and postpartum remodeling has never been quantified. We used statistical shape modeling to compute the 3D variation in PFMC morphology of reproductive-aged nulliparous, late pregnant, and parous women. Pelvic magnetic resonance images were collected retrospectively and PFMCs were segmented. Modes of variation and principal component scores, generated via statistical shape modeling, defined significant morphological variation. Nulliparous (have never given birth), late pregnant (3rd trimester), and parous (have given birth and not currently pregnant) PFMCs were compared via MANCOVA. The overall PFMC shape, mode 2, and mode 3 significantly differed across patient groups (p < 0.001, = 0.002, = 0.001, respectively). This statistical shape analysis described greater perineal and external anal sphincter descent, increased iliococcygeus concavity, and a proportionally wider mid-posterior levator hiatus in late pregnant compared to nulliparous and parous women. The late pregnant group was the most divergent, highlighting differences that likely reduce the mechanical burden of vaginal childbirth. This robust quantification of PFMC shape provides insight to pregnancy and postpartum remodeling and allows for generation of representative non-patient-specific PFMCs that can be used in biomechanical simulations.
特定的肛提肌肌肉成像测量值随妊娠和阴道分娩次数而变化，尽管整个盆底肌肉复合体（PFMC）与妊娠引起的和产后重塑相关的形状变化从未被量化过。我们使用统计形状建模来计算生殖年龄初产妇、晚期妊娠和经产妇的 PFMC 形态的 3D 变化。回顾性收集盆腔磁共振图像并对 PFMC 进行分割。通过统计形状建模生成的变化模式和主成分得分定义了显著的形态变化。通过 MANCOVA 比较初产妇（从未分娩过）、晚期妊娠（第 3 孕期）和经产妇（已分娩且当前未怀孕）的 PFMC。总体 PFMC 形状、模式 2 和模式 3 在患者组之间有显著差异（p<0.001，=0.002，=0.001，分别）。与初产妇和经产妇相比，这种统计形状分析描述了更大的会阴和肛门外括约肌下降、髂尾肌凹陷增加以及中后部分离器裂孔比例更宽。晚期妊娠组最为离散，突出了可能降低阴道分娩机械负担的差异。这种对 PFMC 形状的强大量化提供了对妊娠和产后重塑的深入了解，并允许生成可用于生物力学模拟的代表性非患者特异性 PFMC。
