Unitized penile erection system and tissue expander

In a unitized implantable penile prostheses including an hydraulically activated extendable cavernosal component and a manually controlled fluid transfer system composed of a pump and valve means and wherein said extendable component includes an extendable inner unit and wherein the extendable inner unit is convertible from a flaccid condition to a rigid condition when a sufficient volume of fluid is transferred into the extendable inner unit to substantially fill the same, the improvement comprised of said extendable inner unit being formed by a pair of parallel tubular channels adapted to contain said fluid therein, said channels being defined, at least in part, by walls that extend in an accordion fashion and which have alternating wider and narrower segments, said walls of said pair of parallel tubular channels being connected at multiple locations along at least a major portion of the length thereof at positions of wider segments, said walls of each tubular channel having openings therein at the locations where they are joined with the other tubular channel to allow fluid to flow between the interiors of the pair of the channels at said locations thereby forming a single expandable internal lumen having a substantially figure 8 shaped cross-section.