Injury Causes

An injury to one or both cavernous nerves may occur at any time during removal of the prostate. The injury might be minor in nature, similar to a bruise, or it might be an excision or cutting out of an entire segment of nerve in order to remove cancerous cells that may have infiltrated the tissue around the nerves. The severity of injury caused is entirely dependent upon the closeness of the tumor to the nerves, and how much tissue involving the nerves must be resected. The underlying principle of prostate surgery is that all tumor and cancerous tissue must be removed.

In cases where a large part of the nerve must be removed, the nerve will not function, because there is a gap in the nerve, and signals from the brain to the penis cannot be transmitted. Additionally, scar tissue often forms around nerves that are even partially injured, again blocking sexual impulse transmission through the nerve.

Many groups have studied the outcome of penile erection sufficient for intercourse following prostate surgery. The results seem to be dependent upon how much nerve tissue is left following surgery. Therefore, men with both nerves spared have the highest incidence of adequate erectile function following surgery, and men with one nerve excised and one remaining intact have the next best function. However, this percentage of men may be as low as 30 or 40 % in some series. Men with both nerves resected have a very low incidence, approaching zero percent, of erections following surgery. Men over 50 years of age have significantly worse outcomes generally than men under the age of 50.