Cylinder sizing: less is more.

In penile prosthesis implantation traditional cylinder-sizing techniques frequently result in penile cylinders that are too long for the corpora cavernosa. This can result in premature cylinder wear leading to cylinder aneurysm or fluid loss. Additionally, in the case of the length expanding Ultrex penile prosthesis, cylinders that are too long can result in an S-shaped cylinder deformity. We describe a cylinder measurement technique that avoids the problem of oversizing.