Greater Boston Urology Blog

MRI-Compatible Sacral Neuromodulation Now Available for Bowel & Bladder Dysfunction

In the past, certain patients with overactive bladder (OAB) syndrome and fecal incontinence (FI) couldn't receive sacral neuromodulation because of their need for MRIs. Why? Well, the first sacral modulation device on the market—InterStimTM by Medtronic—can't be used in full-body MRI scans.

Dr. Angel Marie Johnson, the director of our Women's Health Center in Dedham, explains. "Patients who would have otherwise been great candidates for sacral neuromodulation—meaning that they have overactive bladder syndrome or fecal incontinence that hasn't responded to behavioral modifications or medicines—were unable to have this treatment due to their need for MRIs. For example, maybe the patient has a history of GI or breast cancer that requires MRI imaging or a condition as common as knee or back pain. Because the patient would need MRIs in the future, they were no longer candidates for this therapy until recently."

In fact, if by some chance an InterStim patient ever needed an MRI below the head, the InterStim device would need to be removed first.

However, last fall the sacral neuromodulation market changed, thanks to the FDA's approval of Axonics Sacral Neuromodulation System—a system that is MRI-compatible. The FDA has approved the system to treat overactive bladder syndrome as well as fecal incontinence (for similar uses as InterStim from Medtronic).

MRI-compatibility isn't the only positive feature with this new device: the Axonics battery is rechargeable.

Dr. Johnson explains: "The original sacral neuromodulation device, InterStim, has a battery life of five to seven years depending on patient use. That might sound like a long time, but if you're 30 when you get InterStim, you will need multiple battery replacements throughout your lifetime. And so it's nice that there's now a rechargeable option that's been studied to last at least 15 years, so at least three times as long."

When it comes to charging the Axonics device, Dr. Johnson says you either need to charge it for an hour every two weeks or for half an hour weekly. "It's easy to recharge," Dr. Johnson says. "The patient straps a belt around their waist with a little hockey-puck looking device that sends the signal to recharge the battery. I tell my patients to recharge while watching their favorite weekly TV show."

While the Axonics system is an exciting development, Dr. Johnson cautions that InterStim from Medtronic still remains the tried and true medical device for overactive bladder and fecal incontinence.

Dr. Johnson says, "InterStim has been on the market for over 20 years with over 250,000 implanted devices worldwide. But over time, sacral neuromodulation by Axonics could definitely prove to be a game-changer due to its MRI compatibility and ability to recharge. But it's important to note that Medtronic is currently awaiting FDA approval on their new MRI-compatible device and rechargeable system with a projected release date of June 2020."

For now, Dr. Johnson continues to offer both devices to her patients while being hopeful of this new technology. She continues to make her decisions regarding which device to use based on the individual patient, which is the way it should be.

Reminder, overactive bladder syndrome and fecal incontinence can affect women and men.

And both InterStim and Axonics can be used in women and men. So if you're suffering from OAB or FI, consider making an appointment with one of our physicians so you can discuss your options.