Neuromodulation Implantation Settings Variation for Overactive Bladder

The objective of this project is to investigate the outcomes of intermittent versus
continuous stimulation in patients treated with sacral neuromodulation (SNM) for refractory
overactive bladder (OAB) syndrome. In addition, the potential for an improved battery life
with intermittent stimulation will be quantified. Manufacturers recommended settings for
newly implanted impulse generators (IPG); however, no standardized recommendations exist for
further adjustments. Quality studies examining IPG parameters are lacking, partly due to the
numerous setting variables, which can result in a multitude of permutations. When
programming an IPG, an option for cycling simulation (16 seconds on, 8 seconds off) is
available. It is theorized that because of a "carryover" effect, symptom relief will
continue despite the stimulator being off. The potential benefit of the intermittent
stimulation is an improved battery life, which may translate into a less frequent need for
reimplantation with less morbidity. Participants receiving neuromodulation treatment for
overactive bladder symptoms will be routinely fitted with an impulse generator in a
pre-study phase. Patients who experience significant symptomatic improvement will receive a
full bilateral sacral neuromodulator implantation and will be randomized to either
intermittent or continuous stimulation. Participants will fill out voiding logs and surveys
over a 12 week period. At that point, a one-week washout period during which the
neuromodulator will be turned off. The impulse generator will then be turned to the
alternate setting (intermittent or continuous) and the 12 week period will be repeated.
Questionnaires and voiding diaries will be collected at each clinic visit. In total, subject
participation will last approximately 25 weeks after full implantation of the bilateral
leads and pulse generator.

Inclusion criteria:

- patients age 18 to 85 with overactive bladder symptoms refractory to behavioral and
anticholinergic therapy, detrusor overactivity on urodynamic study, surgically fit
with ability to complete study forms, use patient programmer, and return for
follow-up.

Patients must have attempted and failed noninvasive therapy for overactive bladder
symptoms for at least 6 months prior to enrollment; previous treatments will be recorded.
In addition, patients must be fluent in the English language to complete informed consent
paperwork and study questionnaires.

Exclusion criteria:

- dementia,

- neurological conditions (spinal cord injury, multiple sclerosis),

- non-English speaking,

- acute urinary tract infection,

- primary pelvic pain,

- pregnancy or breast-feeding,

- urinary retention (postvoid residual greater than 100mL),

- history of bladder cancer in the past 5 years,

- history of nephrolithiasis or ureterolithiasis,

- anticoagulant therapy,

- implanted pacemaker/defibrillator, or

- anticipated need for future MRI.