The purposes of this study are:

1. To provide evidence from a randomized controlled trial that InterStim Therapy provides better relief of symptoms of OAB than standard medical treatments in current use.
2. To fulfill the requirements of the FDA-mandated post-approval study of the safety of the tined lead using a minimally invasive approach.

Approximately 30 million Americans meet the criteria for overactive bladder(OAB). Urinary voiding dysfunction symptoms impose a significant physical and psychosocial impact on individuals, including loss of self-esteem and a decrease in the ability to maintain an independent lifestyle. These symptoms can substantially affect a subject's daily activities.

Patients with OAB are managed with diet modification, bladder training or retraining, pelvic muscle rehabilitation, medication and biofeedback. Medications are used as the first-line therapy for urgency frequency and urinary urge incontinence.

InterStim Therapy utilizes sacral nerve stimulation and is indicated in the US for the treatment of urinary retention and the symptoms of OAB, including urinary urge incontinence and significant symptoms or urgency-frequency alone or in combination, in subjects who have failed or could not tolerate more conservative treatments.

This protocol will enroll approximately 325 subjects at up to 45 sites in the US to randomize 216 subjects to either InterStim or standard medical therapy for 6 months. At the end of the 6 months, subjects in the standard medical therapy arm would be eligible to try InterStim therapy.

• Device: InterStim Therapy
• Drug: Standard Medical Therapy

• Other: InterStim Therapy
• Active Comparator: Standard Medical Therapy

Inclusion Criteria:

• Have a diagnosis of OAB including urinary urgency-frequency
• Be male or female at least 18 years of age or older
• Be able to consent to participate by signing the Informed Consent
• Be willing and able to attend visits and comply with the study protocol including adequate operation of equipment
• Have failed or are not a candidate for more conservative treatment (e.g. pelvic floor training, biofeedback, behavioral modification)
• Have failed or could not tolerate (stopped taking medication due to lack of efficacy or intolerable side effects) at least one anticholinergic or antimuscarinic medication AND have at least one anticholinergic or antimuscarinic medication not yet attempted

Exclusion Criteria:

• Have severe or uncontrolled diabetes or diabetes with peripheral nerve involvement
• Have concomitant medical conditions which would limit the success of the study procedure
• Have skin, orthopedic or neurologic anatomical limitations that could prevent successful placement of an electrode
• Have neurological diseases such as multiple sclerosis, clinically significant peripheral neuropathy or complete spinal cord injury (e.g., paraplegia)
• Have knowledge of planned MRIs, diathermy, microwave exposure, high output ultrasonic exposure, or RF energy exposure
• Have urinary tract mechanical obstruction such as benign prostatic hypertrophy, cancer, or urethral stricture
• Have symptomatic urinary tract infection (UTI). Upon completion of therapy for UTI, or if the subject is receiving prophylaxis for UTI, the subject can be considered for study entry if he/she is symptom-free for one month prior to randomization.
• Have implantable neurostimulators, pacemakers, or defibrillators
• Have primary stress incontinence or mixed incontinence where the stress component overrides the urge component
• Have a primary diagnosis of Interstitial Cystitis
• Have had treatment of urinary symptoms with botulinum toxin therapy in the past 12 months
• Be a woman who is pregnant or planning to become pregnant or are a woman of child-bearing potential who is not using a medically-acceptable method of birth control.