Penile extensibility: to what is it related?

Penile extensibility is the difference between the length of the flaccid penis and the penis submitted to a maximal constant traction. This measurement has been proposed for use as a new potential diagnostic method to assess intracavernous fibrosis. To determine the value of this method we measured penile extensibility before and after removing the skin and cavernous tissue in 17 cadavers and 4 patients undergoing penile implantation. In all cases a cavernous tissue biopsy was performed and the percentages of the different structures were objectively quantified by computer analysis. The extensibility decreased with patient age but it was not influenced by removal of the skin and/or cavernous tissue. No correlation was observed between decreased extensibility and the increase in fibrotic elements in the penile tissue. Penile extensibility seems to reflect the elasticity of the tunica albuginea, which is the limiting factor and cannot be an expression of fibrosis of the corpora cavernosa.