Distance Between Reproductive Structures and the Insertion Point of the Retrograde Pubic Ramus Screw

To identify the distance between the guidewire for a retrograde pubic ramus screw and critical reproductive structures in men and women.

Twenty hemipelves from 10 fresh-frozen cadavers (pelvis to distal femur) were studied. The mean (±SD) age was 77 ± 6 years for the 5 male cadavers and 71 ± 9 years for the 5 female cadavers. A 2.8-mm guidewire for a cannulated screw was inserted from the parasymphyseal bone using fluoroscopic guidance. The soft tissue was dissected and measurements performed by the first author. In men, we measured the closest distances from the guidewire entry point to the contralateral spermatic cord and corpus cavernosum. In women, we measured the closest distances from the guidewire entry point to the base of the clitoral body and clitoral glans.

In male cadavers, mean distances were 8.8 ± 4.2 mm to the spermatic cord and 13 ± 6.7 mm to the corpus cavernosum. The guidewire did not penetrate these structures in any specimen. In female cadavers, mean distances were 12 ± 5.7 mm to the base of the clitoral body and 40 ± 8.2 mm to the clitoral glans. The guidewire also did not penetrate these structures.

The contralateral spermatic cord and corpus cavernosum in men and the base of the clitoral body in women are close to the pathway of the retrograde ramus screw guidewire. Careful identification of the entry point and avoidance of multiple attempts of guidewire insertion may reduce the risk of injury to these structures.