Intra-operative Assessment of Cavernosal Nerve Stimulus Threshold

Inclusion Criteria: * Subjects must have prostate cancer being treated via radical prostatectomy by a single surgeon (primary investigator) with planned intraoperative nerve sparing. * Subjects must have intact preoperative erectile function, sufficient for penetrative intercourse without medication nor assistive device, as defined by a Sexual Health Inventory for Men (SHIM) / International Index of Erectile Function (IIEF-2) score 22 or higher, which is collected as part of routine care. * Subjects must have the ability to understand and the willingness to sign a written informed consent document. Exclusion Criteria: * Baseline erectile dysfunction, as defined by the use of medications or devices to assist erection, lack of baseline erections, or a SHIM / IIEF-2 21 or lower, which is collected as part of routine care. * Lack of successful intraoperative nerve sparing. * Neurologic, metabolic, or vascular diseases that may negatively impact erectile function, such as: diabetes mellitus, peripheral vascular disease, coronary artery disease, stroke, multiple sclerosis, parkinson's disease, multiple systems atrophy, epilepsy, or spinal cord injury. * Inability to provide a fully informed consent.