Subjects will have their leg and foot draped to remain blinded to the test. They will be in a supine position with the knees abducted and flexed. The medial aspect of the lower extremity is palpated and a needle insertion site is identified. Between the posterior margin of the tibia and the soleus muscle, an acupuncture-like needle is inserted. An adhesive grounding pad is placed on the bottom of the foot just below the smallest toe. The needle and grounding pad are connected to the stimulator and the stimulation is increased as tolerated.

Since subjects with the PTNS will feel foot stimulation, the sham was devised to mimic this feeling without the tibial nerve being stimulated. Again the leg and foot will be draped and out of view from the subject. The medial aspect of the lower extremity is palpated (Figure 4) and the tibial nerve site is identified approximately 5 cm cephalad from the medial malleolus. A Streitberger needle is used at the tibial nerve insertion site to simulate needle placement without puncturing the skin. The needle will be taped in place as in the PTNS procedure. The "grounding pad" will be a gel electrode pad from a TENS unit device that is placed on the bottom of the foot just below the smallest toe.

The PTNS device (Urgent® PC) is a minimally invasive neuromodulation system designed to deliver retrograde access to the sacral nerve through percutaneous electrical stimulation of the tibial nerve (PTNS). It is a combination of a stimulator and a lead set. The stimulator is a battery powered, external pulse generator and is designed, constructed, and manufactured for multiple use in conjunction with the lead set. The lead set (comprised of the lead wires, needle electrode, and alcohol pad) transfers the electrical current from the stimulator to the tibial nerve via the needle electrode. The tibial nerve travels up the leg to the sacral nerve plexus which regulates the bladder and pelvic floor function.