Until the early 1970s, if problems with penile blood flow or nerve function meant a guy couldn't get it up, his choices for treatment were pretty limited, and certainly did not mimic nature.
There were external props that could be strapped to a flaccid penis. There were a few implantable props that made the penis permanently stiff, but men using these devices not only had to worry about all the issues of having a permanent boner, sometimes the devices would rub a hole through the skin and fall out. Eew.
Berish Strauch thought an inflatable option might work better, and the development of flexible plastics made it possible. In 1973, he proposed an implantable device that would embed a fluid reservoir (22 in the diagram above) inside the scrotum (12) or the abdomen (14), connected to a flexible tube (18) running along the top of the penile shaft (16). The impotent patient could pump the tube full whenever he felt like some sexytime.
In this way it is possible to stretch and elongate the tube and render it relatively rigid so as that a penile erection will result. The return of the fluid under pressure from the time to the container is delayed so that an erection will be maintained for a satisfactory period of time.
Fluid would be locked inside the tube by a series of tiny metal pressure plates. Getting the fluid out of the penis was decidedly manual.
However, when it is desired to eliminate the erection, the tube will be milked rearwardly by suitable manipulations along the penile shaft. This pinching and rearward milking applied to the tube forces the fluid rearwardly… with a pressure sufficient to deflect the wall…
It's like masturbating in the mirror universe.
Strauch never developed his design. Instead, he sold the idea to American Medical Systems, where Brantley Scott and his colleagues refined it: turning the elastic tube into a pair of balloon like reservoirs, and implanting them inside the penile erectile bodies. Improved versions of that design are still in use today. [US Patent 3853122 A [Simmons and Montague 2008]
Image: US Patent 3853122 A