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Therapy

Axonics vs Medtronic: Which is the Best Sacral Neuromodulation Therapy?

Dr. Joe Pazona

Coke vs. Pepsi. McDonalds vs. Burger King. Yankees vs. Red Sox. Rivals and competition are a good thing. Without competition, companies have less incentive to improve, innovate and serve their clients. In the world of sacral neuromodulation, this is no different.

Axonics and Interstim are the two big players in sacral neuromodulation. Very little information is available for you, the patient, or even us physicians for that matter, on the pros and cons of these therapies. Therefore deciding on “the best” sacral neuromodulation therapy can be challenging.

That’s where VirtuCare comes in. We love challenges. We specialize in educating patients on all topics urological, including the best surgical sacral neuromodulation therapy for an overactive bladder (OAB).

Although we may have our favorite (stay tuned for the winner), the good news is that both of these therapies are effective overactive bladder therapies and have literally changed the lives of tens of thousands of people across the world.

If you’re considering either therapy, and don’t like reading, then you can skip to the front of the line with a urology telemedicine consultation today. You can have an affordable video visit with a urologist and have all your sacral neuromodulation questions answered in real time.

Our board-certified urologists are specialists in guiding patients to the best treatments. We have a large network of colleagues throughout the country, so we can even ease a referral to the best surgeon for your sacral neuromodulation trial.

 

If you’re not ready for a consultation quite yet, let’s dive into this topic and decide the battle of Axonics vs. Medtronic!

Axonics vs. Medtronic: Introduction to Sacral Neuromodulation

Before we tackle this debate, it’s important that you have a baseline understanding of sacral neuromodulation.

Why should you consider sacral neuromodulation?

 

When your overactive bladder (OAB) is still irritable despite lifestyle changes and medications, it’s time to consider more advanced OAB therapies. This is where sacral neuromodulation comes into play. Along with bladder “Botox” injections and PTNS (percutaneous tibial nerve stimulation), Axonics or Medtronic sacral neuromodulation are considered 3rd line therapies.

 

How do you decide between these three OAB therapies? Here are some tips:

 

  1. If the patient has a lot of medical problems, or barriers to minor surgical procedures, then PTNS may be the best choice because it is an office therapy with no risk.
  2. If you’ve failed the other therapies, and don’t mind the risk of catheter, then bladder botox may be your best option.
  3. If you’re looking for a long-term “cure” with great results, then sacral neuromodulation with Axonics or Medtronic is the answer.

 

Need further help deciding? Speak with the expert by scheduling a urology telemedicine visit today.

 

It’s important to note that sacral neuromodulation doesn’t just treat an overactive bladder. It is also a FDA-approved therapy for fecal (bowel) incontinence and non-obstructive urinary retention (men or women). Although these indications are less commonly discussed, Axonics or Medtronic sacral neuromodulation are effective treatments for these conditions as well.

What is sacral neuromodulation?

Axonics and Medtronic sacral neuromodulation are essentially nerve stimulation procedures. The process of “going potty” requires properly functioning nerves. There is a signaling pathway from:

Brain > spinal cord >  pelvic (sacral) nerves > pelvic organs (bladder and rectum)

When the bladder or rectum are “full”, a signal is sent to your brain saying “hey, you should find a restroom.” On the other hand, when you have an overactive bladder or rectum, the signal is sent more urgently and your brain screams “GO POTTY NOW!” This sense of urgency can leak to bladder or bowel leakage. Not good.

Sacral neuromodulation is a “rewiring” of this faulty nerve pathway which gets the brain, nerves and bladder/rectum back on track. A gentle electrical impulse is delivered to the pelvic nerves (S3 nerve root to be exact), via a small electrode connected to a neurostimulator. This impulse somehow resets the nervous system. How cool is that!

How is sacral neuromodulation performed?

Whether it’s Axonics vs. Medtronic devices, sacral neuromodulation is typically performed in a series of minor surgical procedures.

Axonics vs. Medtronic percutaneous nerve evaluation (PNE)

PNE is a great way to trial sacral neuromodulation before committing to a bigger procedure. It is usually performed in an office setting under local anesthesia. The patient will lie on their stomach and be undressed from the waist down. The area of interest is the sacrum which is the bone connecting your “lower spine” (lumbar vertebrae) to your tailbone (coccyx).

 

sacrum bone

 

After numbing you with local anesthesia, the specialist will place a small needle in both of the natural openings in the sacrum (foramen), leading to the nerves of interest (3rd sacral nerve roots circled above). There is no risk of nerve damage and the PNE only takes 10-15 minutes. After placing an ungodly amount of tape on your back (sorry we don’t want these tiny electrodes to move), you’re back home with no pain.

Before leaving the office, the leads will be connected to an external nerve stimulator and we will test your sensation. At first, you’ll feel a gentle tapping somewhere in the private area (we don’t need to get specific). It neither hurts nor leads to any pleasure (sorry ;). After a while you won’t notice it.

You’ll want to avoid heavy physical activity or getting the area wet in the shower for about a week to prevent the small electrodes from moving out of place. Other than wearing lots of deodorant/cologne/perfume to avoid smelling rank, your only new activity is to keep a bathroom journal to document your number of trips to the potty including any “accidents.”

The great news is that 70% or more of folks have a great improvement in their bladder or bowel leakage. At your one week follow-up visit, the specialist will take off the tape, remove the tiny electrodes and review your potty diary. You’ll then leave the office, run home and shower so your family doesn’t disown you, and wait for a phone call to get scheduled for a permanent Axonics or Medtronic device implantation.

On the other hand, if you didn’t see the improvement in bladder or bowel leakage with either Axonics or Medtronic PNE, then don’t worry because there’s still hope.

It is worth noting, that in my anecdotal experience with both devices, there does not seem to be much of a difference between the Axonics and Medtronic PNE procedure. There are no head-to-head studies looking at the success rates for Axonics vs. Medtronic PNE.

I would not expect there to be a big difference because the electrodes and stimulator used during this trial period are relatively similar and crude compared to the more sophisticated permanent lead and neurostimulators. It is in the full implantation where we see the Axonics vs. Medtronic debate become heated.

Axonics vs. Medtronic advanced trial (stage 1)

For the 30% of patients who don’t positively respond to the PNE, a more advanced trial can be performed. This usually occurs in the operating room under some anesthesia. You’re still on your back but now we are backing a tiny incision to place the “permanent lead”. This lead has 4 different metal electrodes that allow the specialist to modulate the way the electrical stimulation is delivered to your nerves.

 

permanent lead for electrical stimulation

 

With this added flexibility, we can sometimes achieve better results. Also the lead has tiny plastic hooks (tines) that stabilize the lead in place so it doesn’t dislodge. The lead is attached to an external battery device like before.

A repeat trip to the operating room is planned about a week later. That day the specialist will either be removing the lead because it didn’t work again (sorry), or attaching the lead to the permanent “battery” (neurostimulator) and implanting the entire device below your skin (see below).

There are some differences in Axonics vs. Medtronic leads that we will get into below. However again there are no head-to-head trials of stage 1 trials.

Axonics vs. Medtronic: Stage 1 and 2 full implantation

Assuming you’ve had great results from either trial surgery, then the next step is receiving the whole enchilada. A permanent implantation of the lead and neurostimulator.

This is similar to the stage 1 procedure described above. It is performed under anesthesia in the operating room and you go home the same day. The only difference is that the electrode is going to be connected to the permanent neurostimulator (battery device) which is implanted via a small incision in your upper buttocks area. The device will be completely internal. No one will even know you have the Axonics or Medtronic device in place.

 

electrode permanent neurostimulator in upper buttocks

 

Each device has a remote control which will allow anyone to change the settings on how the gentle electrical stimulation is delivered internally. Some batteries are rechargeable, some require replacement after a number of years.

Now that we’re all on the same page, let’s dive into the big questions you may have:

What’s better? Axonics vs. Medtronic sacral neuromodulation.

 

Axonics vs. Medtronic: History of the devices

The first sacral neuromodulation to receive FDA approval was the Medtronic Interstim device in 1998 for the treatment of urge urinary incontinence. This was a momentous event that ushered in a new era of overactive bladder treatments. Until this point, patients were stuck trialing medications that were not great long-term solutions.

As the only kid on the playground for over 20 years, Medtronic’s InterStim device had a monopoly on the market. Although subtle changes were made to the device during this time (e.g. InterStim II with smaller neurostimulator), very little innovation was seen with the therapy.

The device had to be changed every 5 years because the battery ran out. Some patients also complained that the device was too big. Lastly, the device was not MRI-friendly. So if you needed an MRI, the device needed to be removed.

Enter in Axonics. Opportunity sparks innovation. In 2019, Axonics received FDA approval for a new sacral neuromodulation therapy. Compared to Medtronic InterStim, Axonics offered 3 main advantages to the patient:

 

  1. Smaller battery (about the size of a USB card).
  2. Recharging capabilities with over a 15 year device span.
  3. MRI compatible

 

comparing Medtronic and Axonics size

 

Not surprisingly, Medtronic quickly responded in August of 2020 with release of their InterStim Micro neurostimulator and InterStim SureScan MRI lead, which provided another MRI-friendly, small rechargeable device for patients. Now the Axonics vs. Medtronic debate could really begin.

Axonics vs. Medtronic: Clinical results

The easiest way to determine “the best” sacral neuromodulation therapy would be a head-to-head study of Axonics vs. Medtronic InterStim. Unfortunately, this battle has not yet happened on the scientific ball field. We do however, have plenty of patient trials with each sacral neuromodulation therapy showing excellent clinical results.

For the purpose of this discussion, we will focus on the data related to an overactive bladder. Both therapies are also used to treat bowel leakage (fecal incontinence) and non-obstructive urinary retention.

One of the first landmark studies of sacral neuromodulation was the Insite Trial by Siegel in 2014 which compared Medtronic InterStim to standard medical therapy for an overactive bladder. The results showed that 61% of patients with Medtronic InterStim had at least 50% improvement in OAB symptoms and 86% had improved/greatly improved symptom scores.

The RELAX trial in 2019 actively followed patients with Axonics therapy for 1 year. This demonstrated the efficacy and feasibility of the first rechargeable device for an overactive bladder. At 1 year, 94% of patients were still showing >50% improvement in overactive bladder symptoms. A pretty impressive figure considering that patients had to remember to recharge their devices every 2-4 weeks.

For all of the haters who didn’t believe the great results with Axonics, the follow-up ARTISAN trial knocked it out of the park. At 2 year follow-up, 93% of patients achieved at least 50% improvement, 82% achieved >75% improvement and 37% of patients were completely dry with no leakage. Wow.

The success of Axonics in the RELAX and ARTISAN trials certainly suggests that it may be a superior therapy to Medtronic Interstim. Why would this be the case?

Let’s look at some of the features that may be the reason the Axonics vs. Medtronic debate is leaning towards Axonics as the best sacral neuromodulation.

Axonics vs. Medtronic: Differentiating factors

Ease of Programming

Once the sacral neuromodulation device is placed, the physician needs to “program” the device to tell the neurostimulator “how” to stimulate the pelvic nerves. You can vary the voltage, direction and frequency of the electrical current. These determine how well Axonics vs. Medtronic works for patients.

Compared to the original Medtronic programmer, the Axonics programming tool is very easy to use. It’s a large touch screen tablet that’s easy to read. It stores patient responses and uses a proprietary algorithm to determine the best treatment parameters. Rather than guess, the system guides you to the best settings.

The Medtronic programmer was updated in response to Axonics in late 2018 with release of it’s “smart” programmer. It’s the size of a cell phone and has two different platforms for doctors and patients. We don’t have experience with this new programming tool so it’s unclear how “smart” it is as a programmer.

Type of Nerve Stimulation

Once the electrode is placed inside of your body, a capsule or scar tissue begins to form around it (encapsulation). Think of this scar tissue like insulation around other electrical wires in your house. Insulation slows down (impedes is the fancy science term) the electrical current. So you can imagine why encapsulation of the electrode leads to declining results with sacral neuromodulation over time.

In fact, a 5-year study of Medtronic Interstim showed that sacral neuromodulation success decreased from 87% at 1 month to 62% at 5 years. In contrast, the ARTISAN trial with Axonics showed that 92% of patients were still responding to therapy at 2 years. Not a direct apples-to-apples comparison, but this certainly suggests something different is going on.

What is the difference? Unfortunately this requires a bit of science. Axonics uses something called constant current stimulation. Think of this like cruise control in your car. If you’re set at 65 mph, and the car approaches a hill, what happens? The engine revs, works harder and you keep going 65 mph up the hill. This is constant current stimulation. This is how Axonics delivers nerve stimulation.

In contrast, Medtronic Interstim is constant voltage stimulation. Think of this like how hard you’re pushing down on the gas pedal. As you approach the hill, if you don’t press down on the pedal, the car will slow down. The same thing happens to a Medtronic electrode as it becomes encapsulated with scar tissue. You have to keep turning up the voltage until at some point the nerve response decreases.

Patient device

Have you ever heard of the business adage K.I.S.S or “keep it simple stupid?” This is why the iPod took off and my old MP3 player is in the trash. Sacral neuromodulation is intimidating enough for patients. Take a look at the different patient devices from Axonics vs. Medtronic:

 

Axonics patient device

 

The Axonics device is simple. An “ON” button in the middle. Arrow up to increase stimulation which is shown by the bright green lights. Arrow down to decrease the intensity. That’s it. Compared to Medtronic where you need essentially another cell phone. Anecdotally, patients have a clear preference for the Axonics device and it’s easy to see why.

Axonics vs. Medtronic: Conclusion

Well that’s the end of our Axonics vs. Medtronic debate. So which is the best sacral neuromodulation therapy? Certainly Axonics has ushered in a new era of innovation in this exciting treatment space. Medtronic finally has “picked up it’s game” and made some new changes as well. Until we have a battle on the gridiron, it’s not fair to say once therapy is definitely better than the other.

What is important, is finding the best physician with experience in either therapy. Sacral neuromodulation is an effective, long-term solution for an overactive bladder and fecal incontinence.

Not sure where to start? Why not consider a telemedicine visit with a VirtuCare urologist? We are experts in sacral neuromodulation. With a telemedicine visit we can:

 

  • Make certain you are a candidate for sacral neuromodulation.
  • Answer your sacral neuromodulation questions.
  • Refer you to a trusted colleague in your area who performs the sacral neuromodulation of your choice (Axonics or Medtronic).

 

Our experts are here to guide you towards a solution for your bladder or bowel problems. Don’t suffer in silence! Click here to get the care you deserve today.

ABOUT THE AUTHOR

Dr. Joe Pazona

Dr. Joseph Pazona is the founder and President of VirtuCare, a telemedicine solution for connecting patients with physician experts. He can be reached at joe@myvirtucare.com.
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