Sacral neuromodulation therapy is a reversible treatment that uses mild electrical pulses (called electrical stimulation) to stimulate nerves in your lower back, just above the tailbone. These nerves are called sacral nerves. The sacral nerves (specifically S2, S3 and S4) activate or inhibit muscles and organs that contribute to urinary control -- the bladder, sphincter and pelvic floor muscles.  Specifically, S3 influences pelvic floor behavior. The electrical stimulation artificially excites nerve pathways that may activate or inhibit muscle action, depending on their normal function. This may decrease the symptoms of urgency, frequency, urinary retention and urge incontinence.