Surgical implants and procedures for restoring erectile function are described. A method of detecting an unsatisfactory condition of an inflatable penile prosthesis system including a pump, cylinder(s), fluid circuit, a septum and a reservoir. The method including the steps of: i) implanting the inflatable penile prosthesis system in a patient; ii) providing a probe assembly with first and second sensors; iii) placing the first sensor through the septum and into the fluid circuit of the inflatable penile prosthesis system; iv) placing a second sensor outside the penile prosthesis system in the patient's tissue, v) sensing conditions with the first and second sensors, and vi) comparing the conditions sensed by the first and second sensors to detect an unsatisfactory condition.