Secondary Bilateral Sacral Nerve Stimulation in Overactive Bladder Patients
Condition: Bladder Hyperactivity
MeSH terms: Urinary Bladder, Overactive
Study type: Interventional

Summary: 
      Unilateral sacral neuromodulation (SNM) has emerged as a valuable treatment for patient with
      low urinary tract dysfunction when failure or bad tolerance to anticholinergic treatment for
      overactive bladder. However, in the medium or long term, some patients failed to benefit from
      unilateral stimulation (unilateral neuromodulation). A contralateral stimulation could be
      tested then implanted to restore the efficacy. An other option is to perform a bilateral
      stimulation of the sacral nerves that could lead to a summation effects better than
      unilateral stimulation. Therefore, if a unilateral sacral nerve stimulation fails, a
      contralateral or a bilateral test should be considered.
    

Detailed description: 
      Sacral neuromodulation (SNM) is a treatment in non neurogenic (idiopathic) patients with
      overactivity of the bladder (OAB) symptoms, refractory to conservative treatment. After
      selection of patients with positive stimulation test (PNE test), the success rate of
      stimulation implant is approximatively 70% (40 to 80%). Unilateral versus bilateral initial
      implantation was retrospectively compared by Pham et al. with respectively 58 and 77% success
      rate. Wound infection and complication rate were similar. However the limitation of bilateral
      stimulation is an increased cost for the health care system, augmented duration of the
      procedure, possible morbidity. Therefore initial implantation in the first step of the
      treatment is unilateral in current practice. However, after a period of time, a secondary
      failure may happen, either a complete failure with return to initial symptom or a partial
      failure with a decrease of the efficacy that may impact on quality of life. However, a non
      clinical evident effect could have a summation effect if a contralateral stimulator was
      implanted, and possibly better than contralateral alone.

      Research have shown in a small study on 15 patients that a selected group of patients appear
      to benefit from bilateral stimulation test (PNE test) after failure of unilateral S3
      stimulation. A successful response was observed in 4/11 (36%) OAB patients. Bilateral
      stimulation induced a higher clinical response than stimulation of a controlateral lead alone
      in voiding parameters. In the patients who showed a successful response to PNE test, 3 were
      implanted bilaterally with more than 50% improvement for 2 of them at one year follow-up, and
      41% improvement for the third. No painful stimulation or side effects were reported with
      chronic bilateral stimulation. In one study, a lead migration was suspected in 3/15 patients
      and was the cause of failure. Therefore the proposed study will use systematically a tined
      lead electrode that avoid lead migration.

      According to these preliminary data, test stimulation with a contralateral lead might be
      considered in secondary unsuccessful patient and evaluated. Further investigation is
      necessary to determine in a larger cohort the result of contralateral alone or bilateral
      stimulator implantation. There is no established guidelines in secondary unsuccessful
      patients, therefore contralateral stimulation is used in clinical practice according to
      patient and practitioner opinion. This protocol is presented as a standard clinical practice
      evaluation.
    

Intervention name(s): Device: INTERSTIM II
Intervention type(s): Device
Intervention description(s): A second stimulator is implanted on controlateral site
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: relapse after an initial clinical response