Would you agree to have a medical device implanted in your body if there were more than 44,000 adverse events reported to the FDA, including device malfunctions, infections, pain, and problems with wounds healing? Would you agree to surgery if you knew that more than a dozen fatalities had been associated in some way with its use yet had not been explained? What if there were a handful of lawsuits which were “settled.” Such is the conundrum of sacral neuromodulation (aka Medtronics’ Interstim).

Approved for the treatment of urinary urge incontinence (1997) and overactive bladder (1999), a record 350,000 devices have been implanted as of 2021 with some truly life changing results. Imagine the embarrassment of living with fecal or bladder incontinence. Neuromodulation has the potential of restoring continence and control, freeing patients from the discomfort and shame associated with “accidents.” Neuromodulation has also been offered frequently to IC/BPS patients for the management for their frequency and urgency. Some patients have shared success while others have shared failures.

As the IC Support Group Leader in the San Francisco Bay in the 1990’s when Interstim was developed at UC San Francisco, members of my group agreed to have neuromodulation performed. The results were mixed, at best. Evelyn White, my co-leader for our first IC support group here in Northern California had her device fail when she sat in her car after the trial implant. The act of sitting pulled the leads out of position, an early problem so common that the company developed “tined” leads to help them stay in place. She shared that her husband simply pulled them out of her body that night. (You can’t do this today as the leads now have tines that lock them in place)

Back in those earliest of days, the trial leads were often implanted in the sacral area without any anesthesia, leaving members thoroughly traumatized. I’ll never forget one mother describing hearing her son screaming for help at the doctors office as they implanted leads. She said that he was so traumatized that he didn’t speak for days afterwards.

After launching the ICN website, we received yet more patient experiences. A young patient from Florida called the ICN to report that her device was malfunctioning and shocking her painfully. The urologist who implanted the device refused to see her because she had lost her health insurance. She called our office in desperation. There was only one physician in the entire state of Florida at that time who would see Medicaid patients.

Another young woman was thrilled with the results of the trial stimulation and agreed to have the full implant but, after that surgery was completed, it didn’t feel the same. Months later, when her pain became so severe that she couldn’t function, they performed another surgery and found that she had developed gangrene from a deep tissue infection.

Tracking Complications With MAUDE

Neither patients nor most doctors are aware of the growing list of adverse events being reported to the US FDA Manufacturer and User Facility Device Experience (MAUDE) database where we can see, in real time, thousands of reports that contradict the narrative that neuromodulation is easy.1

As of 2021, more than 44,000 adverse events had been filed for Interstim®. And the reports keep coming. In April of 2024, 327 reports have been added to the database. A review of the first five below share common adverse events reporting both injury and device malfunc- tions.

  1. Report Key 19210395 – Event type: Injury – Information was received from a patient with an implanted neurostimula- tor (ins) for urinary dysfunction/sacral nerve stim and gastrointestinal/pelvic floor therapy. It was reported that the patient said their previous stimulator was replaced because the battery kept trying to eject out of their body, it was superficial and it was very hard to charge.
  2. Report Key 19210297 – Event type: Injury – Information was received from a patient who was implanted with an implantable neurostimulator (ins) for unknown indications for use. It was reported that patient had incision reopening/split open. Patient reported to the urology clinic and was instructed to go to the er. This patient has a bilateral implant and are not yet aware of which side the issue is on but it is not affecting both sides. Will update the side once known.
  3. Report Key 19209345 – Event type: Malfunction – Information was received from a patient who was implanted with an implantable neurostimulator (ins) for urinary dysfunction/sacral nerve stim. The reason for call was patient said they just used their external yesterday and got a message: internal device battery low. Reviewed the meaning of the message and redirected to their doctor.
  4. Report Key 19205028 – Event type: Malfunction – Information was received from a patient who was implanted with an implantable neurostimulator (ins) for urinary dysfunction/sacral nerve stim and gastrointestinal/pelvic floor. It was reported that caller indicates that the device is not working for about a year and they have already tried making pro- gramming changes.The caller reports that a year ago in (b)(6) they were hos- pitalized on a vent in septic shock and they think that something happened during that time that “shorted out” the battery and now it’s just dead. The patient was redirected to their health- care provider to further address the issue.
  5. Report Key 19203479 – Event type: Malfunction – Information was received from a healthcare provider regarding a patient who was implanted with an implantable neurostimulator (ins) for unknown indications for use. It was reported that the device was not responding to messages. Tss reviewed the battery and asked if the patient had noticed any changes in their symptoms; the patient hadn’t noticed any changes. The caller noted the patient had an mri scan 3-4 months ago and everything was working fine at that point. Troubleshooting performed during call: ensured they were using the correct app, ensured communicator is not plugged in, and repositioned communi- cator over ins multiple times. Tss also suggested they try turning external equipment off and then back on. Issue not resolved during call; recommended pt follow-up w/ hcp.

Last Winter, a new study from the University of Texas Southwestern was released that discusses safety reporting for sacral neuromodulation via the MAUDE database.2 Their search found 44,122 related adverse events from 1/1/2011 to 9/30/21. They then took a random sample of 1000 of those reports to develop data to summarize/categorize the types of reports given. (*Many of the reports below were associated with accidents and falls after the device was implanted.)

  • 256 reports – patients needed assistance in using/operating their device.
  • 190 reports – loss of efficacy
  • 96 reports – device failures unrelated to the battery
  • 46 reports – dead batteries
  • 67 reports – wound complications 47 reports – device or lead movement/migrations*
  • 64 reports – painful shocks*
  • 81 reports – pain associated with the device*
  • 49 reports – doctor needed assistance during the operation
  • 14 reports – doctor needed assistance in their office
  • 23 reports – parts of the device were left inside the patient during device removal.
  • 64 reports – unrelated medical issues
  • 3 reports – citations for research

The authors state that “most reports submitted .. to MAUDE are not true safety events but rather reflect a need for support from a manufacturer representative for technological troubleshooting…” They suggest that sacral neuromodulation is “remarkably safe technology” but for the patient considering its use or, worse, experiencing an adverse event, it’s not just a matter of technology but also of trauma, many visits to the doctor, and, for some, multiple surgeries.

The authors also found four product liability lawsuits associated with Interstim® devices, which they described as a “shockingly low number based on our prior product liability research.” Yet, they acknowledge that they may have missed cases that were filed at the state rather than federal level, as well as cases which settled “out of court.”

Fatalities Merit Further Study

Another concern lays in the 20+ fatality reports found in the MAUDE database. The latest (Report Key – 18359475) was posted in December of 2023. It says “Information was received from a family member regarding a patient with an implanted neurostimulator (ins) for urinary dysfunction/sacral nerve stim and gastrointestinal/pelvic floor therapy. It was reported that the patient died within hours of the procedure.”

On this report (and most others), is an extensive disclaimer from Medtronic that says:

This report does not constitute an admission or a conclusion by fda, medtronic, or its employees that the device, medtronic, or its employee caused or contributed to the event described in the report. In particular, this report does not constitute an admission by anyone that the product described in this report has any ¿defects¿ or has ¿malfunctioned¿. These words are included in the fda 3500a form and are fixed items for selection created by the fda to categorize the type of event solely for the purpose of regulatory reporting. Medtronic objects to the use of these words and others like them because of the lack of definition and the connota- tions implied by these terms.This state- ment should be included with any information or report disclosed to the public under the freedom of information act. Any required fields that are unpopulated are blank because the information is currently unknown or unavailable. A good faith effort will be made to obtain the applicable information relevant to the report. If information is provided in the future, a supplemental report will be issued.

An October 2022 fatality report (Report Key – 15695732) is also concerning. A healthcare provider called to report that the patient had major surgery. “After surgery pt developed a sacral ulcer and the interstim lead is exposed in the sacral wound. Caller said they are going to use cautery and they may remove the lead. Caller said issue started within the last couple weeks. Caller said pt was admitted to the hospital…Caller said the pt no longer has an interstim managing doctor because their previous doctor has moved.”

Additional information was received which “reported that the major surgery or sacral ulcer was caused by or related to the medtronic device, therapy and/or implant proce- dures…They indicated multiple deep debridements…development of grade iv ulcer…patient deceased.”

We have little information explaining how or why these fatalities, and others, have occurred. Was it a reaction to anesthesia? a pre-existing condition? The MAUDE database doesn’t often provide timely updates.

The AUA Guidelines for IC/BPS encourage “shared decision-making” for treatment decisions.3 They encourage the physician to educate the patient about the pros and cons, potential risks vs. benefits, of potential treatments. But, if they aren’t following the MAUDE reports for Interstim®, is that doctor and/or patient getting the full picture? Does that patient truly understand that some complications can occur? That the device may need to be revised or removed, requiring multiple surgeries. Will their insurance pay for it? If not, can they afford it?

44,000+ adverse events is a stunning number which, in all likelihood, has breached 46,000 in the past two years. We can assume that many of these reports relate to the earliest of days with older technology which has since been refined and improved, yet technological problems persist, leading to patient trauma, stress and cost. The decision to pursue neuro- modulation should be thoughtfully and carefully considered.

We would like to see the MAUDE database become more timely and responsive, especially in cases where fatalities are involved. How are we to make truly informed decisions if we aren’t given more complete information?

References:

1. MAUDA Database – US FDA – https://www.accessdata.fda.gov/scripts/cdrh /cfdocs/cfmaude/Search.cfm

2. Carlton C, et al. Understanding a decade of safety reporting for sacral neuromodulation in the Food and Drug Administration Manufacturer and User Facility Device Experience database. Neurourol Urodyn. 2024;43:3-15

3. Clemens JQ, Erickson DR, Varela NP, Lai HH. Diagnosis and treatment of intersti- tial cystitis/bladder pain syndrome. J Urol. 2022;208(1):34-42.