Outside-in transobturator midurethral sling and the dorsal nerve of the clitoris.

Introduction and hypothesis: An anatomical study on fresh cadavers was done to determine the vulnerability of the dorsal nerve of the clitoris to injury during "outside-in" transobturator sling procedures.

Methods: The dorsal nerve of the clitoris was identified bilaterally in ten fresh cadavers. Transfixing needles marked the inferomedial border of the obturator foramen. The distance between the foramen border and the nerve was measured.

Results: The nerve ran medially in close approximation to the ischiopubic ramus and inferior to the obturator foramen in all specimens. In no instance did the nerve follow an aberrant course traversing the obturator foramen. The mean distance between the inferomedial border of the obturator foramen and the nerve was 9.3 mm, range 3-14 mm.

Conclusions: When the "outside-in" technique is used, the introducer cannot come into contact with the dorsal nerve of the clitoris because the introducer would have to pass through the ischio-pubic ramus. This is not anatomically possible.