Human subjects will be recruited from people with clinically complete spinal cord injury.
Subjects who meet the selection criteria described below will be screened to identify
those whose reflex bladder contractions are inhibited by neuromodulation using low levels
of electrical stimulation via electrodes on the skin over the dorsal genital nerve.
Serial filling cystometries will be performed in the clinical urodynamic laboratories at
the study sites. Bladder capacity and compliance will be recorded for each cytometrogram.
Subjects whose reflex bladder contractions are significantly inhibited by this
neuromodulation will be offered enrollment in the trial. Subjects whose reflex bladder
contractions are not significantly inhibited by this neuromodulation, or who do not wish
to participate in the study, will be able to continue with their usual form of bladder
management.
After screening, selected subjects will be offered surgical implantation of a Vocare
Bladder System in the FDA-approved manner, but without posterior rhizotomy. Because
posterior rhizotomy is not performed, the afferent axons in the sacral nerves are intact
and can be stimulated after surgery via the electrodes connected to the implanted
stimulator.
The Vocare Bladder System will be implanted in the FDA-approved manner but without
posterior rhizotomy.
After implantation, subjects will be evaluated in the urodynamic laboratory. Stimulation
will applied to S34 sacral nerves bilaterally, and the effects on bladder capacity and
continence and voiding will be measured.
Continence of urine will be documented by bladder diaries. These diaries will be
completed initially as an inpatient in the SCI Service and then at home while applying
neuromodulation via the implant.
It is expected that sacral neuromodulation by this method will be associated with a
significant increase in bladder capacity and continence.
It is possible that this neuromodulation will not be associated with an increase in
bladder capacity or continence. If so, subjects will still be able to use conventional
methods of managing continence and should have no loss of function.
Participants whose bladder capacity and continence are improved by neuromodulation using
the implanted stimulator will be offered the opportunity to continue to use the
stimulator for the duration of the study and will be reviewed at three-month intervals.
At the end of the study they will be reviewed again with their usual clinician and if
there are no contra-indications to continued use of the stimulator will be offered the
opportunity to continue its use under continued clinical follow-up from their usual
clinician.
Participants whose bladder capacity and continence are not improved by neuromodulation
using the implanted stimulator, or who do not wish to continue using the implanted
stimulator, will be reviewed with their usual clinician and offered the bladder
management they were using prior to the study. The implanted stimulator will be switched
off, but will not be removed unless the participant wishes it to be removed or the
investigators or the participant's usual clinician consider it in the participant's
interest to be removed. It is usually simpler and safer for the participant to leave the
stimulator implanted but inactive.
All participants will be provided with appropriate documentation regarding safety and
electromagnetic compatibility of the device.
The investigation is justified because the potential benefits are greater than the
potential risks, as follows:
The potential benefit of the research to the subjects are:
Improved bladder capacity
Improved continence
The potential benefits of the research to others are:
Evidence that bladder capacity and continence after spinal cord injury can be improved by
electrical stimulation without cutting nerves.
The risks to subjects are reasonable in relation to the anticipated benefits to subjects
and others because of
The high prevalence and severity of clinical complications caused by bladder
complications after spinal cord injury
The paucity of methods of restoring continence after spinal cord injury that are
safe, effective and without undesirable side effects
This study is primarily aimed at demonstrating safety, feasibility and proof of concept.
It may also produce statistically and clinically significant evidence of efficacy that
can be used to plan future clinical trials.
Significance:
If the technique of reducing reflex bladder contraction by implanted stimulation of the
S34 nerve bilaterally is successful, it will open the door to more effective use of
neuromodulation for continence after spinal cord injury.
