Muro Satoru, Shoji Sunao, Aoki Meiko, Tharnmanularp Suthasinee, Nimura Akimoto, Akita Keiichi
Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, Tokyo, Japan.
Department of Urology, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
Prostate. 2025 Nov;85(15):1440-1448. doi: 10.1002/pros.70030. Epub 2025 Aug 7.
The role of preserving the superior fascia of the pelvic diaphragm in the context of urinary function remains unclear. This study aimed to investigate the anatomical relationship between the superior fascia of the pelvic diaphragm and the external urethral sphincter in terms of preventing postoperative urinary incontinence. We hypothesized that the external urethral sphincter would be supported by the fascia, smooth muscle, and levator ani muscle.
Three cadavers were used, and the pelvis was dissected to explore the superior fascia of the pelvic diaphragm, levator ani muscle, and external urethral sphincter. Tissue samples underwent wide-range serial sectioning, Masson's trichrome staining, and immunohistochemical staining for smooth muscle actin. Serial histological sections were reconstructed three-dimensionally.
Macroscopic examination revealed the superior fascia of the pelvic diaphragm as a fibrous membrane covering the levator ani muscle. Histology identified interposing smooth muscle tissue between the levator ani muscle, superior fascia, and the external urethral sphincter. Three-dimensional reconstruction revealed this smooth muscle filling the space between the superior fascia and external urethral sphincter, extending medially and laterally, and connecting with surrounding structures.
This study clarified the anatomical details of smooth muscle tissue interposed between the superior fascia of the pelvic diaphragm, external urethral sphincter, and levator ani muscle. This smooth muscle, continuous with the superior fascia, likely forms a supportive structure stabilizing the external urethral sphincter, playing a crucial role in urinary continence. During robot-assisted radical prostatectomy, selection of the dissection plane should consider preservation of these supportive structures to maintain postoperative urinary function.
在泌尿功能方面，保留盆膈上筋膜的作用仍不明确。本研究旨在探讨盆膈上筋膜与尿道外括约肌之间在预防术后尿失禁方面的解剖关系。我们假设尿道外括约肌由筋膜、平滑肌和肛提肌支撑。
使用三具尸体，对骨盆进行解剖，以探究盆膈上筋膜、肛提肌和尿道外括约肌。对组织样本进行大范围连续切片、Masson三色染色和平滑肌肌动蛋白免疫组化染色。对连续组织学切片进行三维重建。
大体检查显示盆膈上筋膜为覆盖肛提肌的纤维膜。组织学检查发现肛提肌、盆膈上筋膜和尿道外括约肌之间存在平滑肌组织。三维重建显示该平滑肌填充了盆膈上筋膜和尿道外括约肌之间的间隙，向内侧和外侧延伸，并与周围结构相连。
本研究阐明了盆膈上筋膜、尿道外括约肌和肛提肌之间平滑肌组织的解剖细节。这种与盆膈上筋膜连续的平滑肌可能形成一个稳定尿道外括约肌的支撑结构，在尿失禁控制中起关键作用。在机器人辅助根治性前列腺切除术中，解剖平面的选择应考虑保留这些支撑结构，以维持术后泌尿功能。
