Sacral neuromodulation seen to ease MS-related bladder dysfunction
Implanted device shows 'sustained efficacy' in 51% of patients in study
Sacral neuromodulation (SNM), in which an implanted device delivers mild electrical pulses to the nerves that control the bladder, led to sustained improvements in urinary function in half of people with multiple sclerosis (MS) who underwent surgery to have the device put into place, according to a review of medical records.
While just 49 people with MS received the device, the researchers nonetheless noted that this was, to their knowledge, the largest study of its kind involving MS patients, with follow-up of slightly longer than six years.
Overall, SNM was found to have “sustained efficacy” in easing bladder dysfunction in 51% of the MS patients in the study, with “just over half of patients … [continuing] to perceive benefit from their therapy over an average follow-up duration of just over 6 years,” the researchers wrote.
The study, “Sacral neuromodulation outcomes in the management of lower urinary tract symptoms in multiple sclerosis patients,” was published in the journal Continence.
As many as 4 of every 5 MS patients experience bladder dysfunction
As many as 4 of every 5 people with MS experience some form of bladder dysfunction, also called LUTS, for lower urinary tract symptoms. Common issues due to LUTS range from an overactive bladder, or the need to urinate very frequently or urgently, and an inability to hold in urine, known as incontinence, to trouble starting urination, and incomplete emptying of the bladder.
MS-related bladder problems can be managed with medications and other treatments, such as physical therapy to strengthen the pelvic floor muscles, which support the bladder, bowel, and uterus in women. Lifestyle changes related to diet or fluid intake may also help.
SNM, also called sacral nerve stimulation, is a minimally invasive surgical procedure in which a device implanted in the body delivers mild electrical pulses to the sacral nerves. These nerves extend from the base of the spinal cord through the sacrum, the triangular bone at the base of the spine, into various parts of the lower body, including the bladder and bowels. In many patients, SNM has been shown to be effective in managing bowel incontinence.
Little has been detailed, however, about the success of SNM in managing bladder dysfunction in people with MS. To learn more, a team led by U.S. researchers reviewed the medical records of 58 MS patients who sought to undergo the procedure between 2013 and 2022.
A total of 51, or nearly 90%, of the patients were women. Relapsing-remitting MS was the most common MS type, seen for 66%, followed by primary progressive MS, diagnosed for 17%. The most common indication for SNM was urinary urgency and frequency, affecting 69%. Nonobstructive urinary retention — when the bladder can’t empty despite no physical blockage in the urinary tract — was seen for the remaining 31%. The mean follow-up was 6.1 years.
Some patients (71%) also underwent urodynamic testing, which assesses the function of the bladder and urethra in storing and releasing urine. The most prevalent finding was an overactive or underactive bladder muscle, called the detrusor muscle. Detrusor sphincter dysynergia, the lack of coordination between the bladder muscle and the urethral sphincter during urination, was also found.
Sacral neuromodulation indicated for patients with certain urinary problems
Patients underwent preliminary testing to assess whether they might benefit from permanently implanting a pulse generator (IPG), the device that delivers electrical pulses in SNM. This included peripheral nerve evaluation, in which a thin wire was temporarily placed near the sacral nerves, or the placement of a single permanent wire. Patients were eligible for permanent IPG placement if the preliminary testing reduced urinary dysfunction by at least 50%.
In total, 49 of the 58 patients (85%) progressed from the preliminary testing phase to IPG implantation, which occurred at a higher rate among those with urinary urgency and frequency than urinary retention (95% vs. 61%). The implantation rate was 56% for patients with detrusor underactivity and 100% for detrusor sphincter dysynergia, but it was similar regardless of preliminary testing methods.
Patients with nonobstructive urinary retention were less likely to receive the IPG implant, while those with a higher body mass index, or body fat content based on height and weight, were more likely to do so. No relationship was identified between IPG implant rates and MS type, urodynamic data, medication use, or prior catheter use.
SNM [sacral neuromodulation] is an effective treatment option for LUTS [lower urinary tract symptoms] associated with MS, … [though] many patients will experience declining efficacy as time progresses.
Of the 49 patients who received the IPG implant, SNM continued to be effective in easing bladder dysfunction in half (51%), while the other half reported decreased efficacy over time, the data showed. Still, no factors were found to predict sustained efficacy.
The researchers noted that “this patient cohort represents the largest [group] of MS patients undergoing SNM therapy to date.”
Overall, the team concluded that “SNM is an effective treatment option for LUTS associated with MS,” though they noted that “many patients will experience declining efficacy as time progresses regardless of indication for implantation.”
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