Department of Obstetrics and Gynecology, Valme University Hospital, 41014 Seville, Spain.
Department of Obstetrics and Gynecology, University of Seville, 41014 Seville, Spain.
Tomography. 2022 May 6;8(3):1270-1276. doi: 10.3390/tomography8030105.
The relationship between the anorectal angle (ARA) and the levator ani muscle (LAM) is well known. In this study, we aimed to demonstrate that the ARA changes when LAM avulsion occurs after vaginal delivery. This was a secondary, observational retrospective study with data obtained from three previous studies. Using transperineal ultrasound, the presence of avulsion was assessed when abnormal insertion of the LAM was observed in three central slices. In addition, the ARA was assessed in the midsagittal plane (at rest, in Valsalva and at maximum contraction) as the angle between the posterior border of the distal part of the rectum and the central axis of the anal canal. The ARA was higher in patients with bilateral LAM avulsion than in patients without LAM avulsion at rest (131.8 ± 14.1 vs. 136.2 ± 13.8), in Valsalva (129.4 ± 15.5 vs. 136.5 ± 14.4) and at maximum contraction (125.7 ± 15.5 vs. 132.3 ± 13.2). The differences between both groups expressed as the odds ratio (OR) adjusted for maternal age were 1.031 (95% confidence interval (CI), 1.001-1.061; = 0.041) at rest, 1.036 (95% CI, 1.008-1.064; = 0.012) in Valsalva and 1.031 (95% CI, 1.003-1.059; = 0.027) at maximum contraction. In conclusion, LAM avulsion produces an increase in the ARA at rest, during contraction and in Valsalva, especially in cases of bilateral LAM avulsion.
肛直角（ARA）与肛提肌（LAM）之间的关系众所周知。本研究旨在证明阴道分娩后 LAM 撕裂时 ARA 会发生变化。这是一项二次、观察性回顾性研究，数据来自三项先前的研究。通过经会阴超声，当在三个中央切片中观察到 LAM 异常插入时，评估撕裂的存在。此外，在正中矢状面（休息时、瓦氏动作时和最大收缩时）评估 ARA，即直肠远端后缘与肛门管中轴线之间的夹角。在休息时（131.8 ± 14.1°比 136.2 ± 13.8°）、瓦氏动作时（129.4 ± 15.5°比 136.5 ± 14.4°）和最大收缩时（125.7 ± 15.5°比 132.3 ± 13.2°），双侧 LAM 撕裂患者的 ARA 高于无 LAM 撕裂患者。两组之间的差异表示为调整母亲年龄后的比值比（OR），在休息时为 1.031（95%置信区间（CI），1.001-1.061；=0.041），在瓦氏动作时为 1.036（95%CI，1.008-1.064；=0.012），在最大收缩时为 1.031（95%CI，1.003-1.059；=0.027）。总之，LAM 撕裂会导致休息时、收缩时和瓦氏动作时 ARA 增加，尤其是双侧 LAM 撕裂时。
