Nerve preservation in tension-free vaginal mesh procedures for pelvic organ prolapse: a cadaveric study using fresh and fixed cadavers.

The aims of this study were, using fixed and fresh cadavers, to clarify how closely the pelvic splanchnic nerve, levator ani nerve (LAN), and sacrospinous ligament (SSL) are located and to examine how to avoid nerve injury during the posterior tension-free vaginal mesh procedure (TVMP), in which mesh is applied through the SSL. Macroscopic dissection of fixed cadavers demonstrated that the LAN crossed the inside of the SSL at a point 0-18 mm medial to the ischial spine and entered the muscle at a point 12-26 mm inferior to the ischial spine and 40-55 mm anterolateral to the coccyx. Dissection after TVMP of fresh cadavers revealed that the point of penetration of mesh through the SSL was close to the LAN. To preserve the LAN, penetration of the SSL should be within 5 mm of the lower margin at a point 20-25 mm medial to the ischial spine.