From the Department of Obstetrics and Gynecology, Fuzong Clinical College of Fujian Medical University, Fuzhou, China.
Female Pelvic Med Reconstr Surg. 2020 Sep;26(9):585-590. doi: 10.1097/SPV.0000000000000637.
The aim of this study was to analyze quantified displacements of the posterior vaginal wall (PVW) on dynamic magnetic resonance imaging (MRI), which may generate hypotheses for the detailed mechanisms that underlie the development of posterior vaginal prolapse.
Pelvic dynamic MRI scans were obtained for 12 women with normal vaginal structure (stage 0) and 62 women with 4 consecutive stages (1-4) of posterior vaginal prolapse. Structural locations (apex vagina, distal vagina, and mid-perineal body [PB]) and equidistant points along the PVW (points 4-6 were considered as midvagina) were identified, and PVW length, straight distance of PVW, levator ani parameters (levator hiatus length [LHL], levator hiatus width [LHW], levator plate angle, anorectal angle, and M line [ML]), urogenital hiatus, and prolapse diameter were measured at rest and maximal Valsalva, respectively. The displacement of these measurements was obtained.
From stage 0 to 2, the variables LHL, LHW, levator plate angle, anorectal angle, and ML increased gradually, but midvagina, distal vagina, and mid-PB were the opposite. From stage 2 to 3, apex vagina, midvagina, distal vaginal, mid-PB, LHL, LHW, and ML raised rapidly and peaked at stage 3, then declined at stage 4. In addition, the correlation coefficients between each measurement from stage 2 to 3 were statistically higher than those from stage 0 to 2.
Quantified displacements of the PVW and its supporting structure were shown on dynamic MRI, and the mechanical mechanisms were hypothesized regarding the interaction between pressure and the support force contributing to the deformation of the PVW and the supporting structures.
本研究旨在分析动态磁共振成像（MRI）下阴道后壁（PVW）的量化位移，这可能为导致阴道后壁脱垂发展的详细机制提供假设。
对 12 名阴道结构正常（0 期）和 62 名阴道后壁脱垂连续 4 个阶段（1-4 期）的女性进行盆腔动态 MRI 扫描。确定结构位置（阴道顶点、阴道远端和会阴体中部[PB]）和 PVW 等距点（考虑到中阴道，将点 4-6 作为中阴道），并在休息和最大valsalva 时测量 PVW 长度、PVW 直线距离、肛提肌参数（肛提肌裂孔长度[LHL]、肛提肌裂孔宽度[LHW]、肛提肌板角度、肛直肠角和 M 线[ML]）、尿生殖裂孔和脱垂直径。获得这些测量的位移。
从 0 期到 2 期，LHL、LHW、肛提肌板角度、肛直肠角和 ML 逐渐增加，但中阴道、阴道远端和会阴体中部则相反。从 2 期到 3 期，阴道顶点、中阴道、阴道远端、会阴体中部、LHL、LHW 和 ML 迅速上升并在 3 期达到峰值，然后在 4 期下降。此外，从 2 期到 3 期，各测量值之间的相关系数均显著高于从 0 期到 2 期。
在动态 MRI 上显示了 PVW 及其支持结构的量化位移，并假设了压力与支撑力之间的相互作用的机械机制，这些相互作用导致了 PVW 和支撑结构的变形。
