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 of urgency-frequency alone or in combination, in subjects who have failed or could not tolerate more conservative treatments.

InSite OAB Protocol 1634 consists of two phases; Phase I which is the randomized portion of the trail and Phase II the non-randomized portion.

Phase 1: A minimum of 60 subjects randomized to InterStim and a minimum of 60 subjects randomized to SMT.

Phase 2: Non-randomized, all qualified subjects will receive InterStim, approximately 297 enrolled Subjects previously enrolled in Protocol 1634 for Urinary Urge Incontinence and Protocol 1635 for Urgency-Frequency will be included in Phase I of the new Protocol 1634 of OAB.

Inclusion Criteria:

• Have a diagnosis of OAB including urinary urge incontinence or 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
• Have been on current regiment of OAB medications or have not been on any OAB medications, for at least 4 weeks prior to beginning the baseline voiding diary

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)
• Have implantable neurostimulators, pacemakers, or defibrillators
• Have primary stress incontinence or mixed incontinence where the stress component overrides the urge component
• 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
• Have a life expectancy of less than one year
• Have plans to enroll in another investigation device or drug trial during their participation in this trial, or currently enrolled in an investigational device or drug trial

Randomization to 6 months follow-up for InterStim arm and Standard Medical Therapy arm in randomized cohort. Implant to 5-year follow up for all implanted cohort.

This section presents the adverse events (regardless device related or otherwise) occurred between randomization and 6 months follow-up in the randomized cohort; and the adverse events (regardless device related or otherwise) occurred post implant through 5-year follow-up for all implanted cohort. The adverse events post implant for InterStim arm subjects in randomized cohort were also included in the adverse events summary of all implanted cohort.

Predominantly female and Caucasian subjects could detract from generalizability. Centers followed individual protocols for peri-op antibiotics, lead choice, and procedure techniques. Lack of standardization may have impacted overall study results.