Introduction and hypothesis: Pelvic organ prolapse (POP) is a common gynecological disease caused by defects in pelvic support tissue that manifests as the descent of the pelvic organs, significantly impacting patient quality of life. Transvaginal mesh (TVM) is an effective treatment (Grade A). However, postoperative pain in the groin and medial thigh is very common. Although the use of mesh for transvaginal POP repair has been prohibited or the indications for such use have been extensively limited in many places, it is still an alternative in some countries. Therefore, the safety of the use of mesh still needs to be discussed. The current research on postoperative pain has mainly focused on management. The pathophysiology is unclear.
Methods: In this study, anterior TVM surgery was performed on ten frozen cadavers. The obturator area was carefully dissected. We explored the relative position of the polypropylene mesh to the internal segment of the obturator nerve in the obturator canal.
Results: Four out of 20 obturator explorations were insufficient to allow conclusions to be drawn. We observed a small branch of the obturator nerve, which is a new anatomical finding that we named the obturator externus muscle branch. This structure terminated in the external obturator muscle in 6 out of the 16 successfully dissected obturator areas. The mean distance between the superficial mesh arm and this nerve branch was 7.5 mm. The mean distance between the deep mesh arm and the closest nerve branch was 5.5 mm.
Conclusion: The path of the obturator externus muscle branch of the obturator nerve ran close to the mesh arm. It may provide a clinical anatomical basis explaining the observed postoperative pain.
Keywords: Anatomy; Obturator nerve; POP; Postoperative pain; TVM.
© 2021. The International Urogynecological Association.