EEVblog #1027 - Implantable NeuroStimulator Teardown

What's inside an implantable Medtronics Itrel 3 Neurostimulator designed for Neuropathic pain reduction.
Dave tears into the ultrasonically welded titanium case.

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[hohoking]

I've been battling extraordinary pain down my legs for almost 20 years. I've had one of these implanted for over 10 years now and it's amazing. I have multiple electrodes woven into my mid-spinal cord with the stim-pack just above my belt-line. The version I have is rechargeable using inductive charging, very cool. Literally saved my life! Thanks for taking this one apaaart!

[MikeDesertHunterHale]

I've had 5 back fusions, the last surgery was ONE week ago. The neurosurgeon fused my neck from 2, 3, 4, 5, 6.7.... I'm still pretty sore. For a number of years, I had the Medtronic Spinal Stimulator implanted. Initially, the surgeon does a trial to see if the simulator is going to be useful, the implants are placed along the spine, the actual unit is left outside the body. Many many different adjust can be made (programmed) IF the unit works it is implanted, this is where I had a problem, the trial worked wonderfully the implanted device never did live up to its potential. The unit had a charging circuit that allowed the battery to be charged through the skin. Finally, after fighting it for years I had it removed.
I also have a second Medtronic device implanted, this is a pump that contains several drugs for pain. The main drug is Hydromorphone, it's delivered straight into my spine 24hrs a day, period... I've had 2 of them now for more than 10 yrs.... Since the Doctors have decided that narcotics are bad, they are turning the dose down, not much fun after ten years. That is a totally different story...

[richardboyce]

Great video. I've had two spinal fusions and long story short I have a Medtronic device implant to help with the pain. My unit has 16 electrodes implanted in the epidural sack around the spinal cord. The battery pack / computer in my case is in my butt and the electrodes are in my thoracic spine (t9 - t12). The unit is charged via am inductive charge unit (about once a week) and has a "usable life" of up to 10 years. I have several programs for different areas of pain but in short I couldn't live without it. Thanks for the breakdown, being a nerd myself it's great to see inside the device inside me/ Cheers. Medtronic I believe pioneered this technology.

[laughingachilles]

I don't know about this specific implant, but a colleague works in this area and she was telling me about the latest developments. The device she helped develop is designed to interrupt seizures in patients with non-cancerous growths, typically cysts which are in an area of the brain upon which it would be dangerous to operate. The reed switch in the devices she works on are there for the patients carer/partner to operate when the person is having a seizure. They swipe a magnet across to activate/deactivate the device. It's a fascinating bit of medical tech and it's helped a great many people. I think she said the success rate was around 60%, the remaining 40% either had no benefit or their condition was made worse. I can't remember the exact figures I'm afraid and it's an early trial so I'm sure things will be tweaked to become even more effective.

[peter]

This was one of the most enjoyable teardowns in a while, keep up the good work Dave!

[Dingomush]

I am on my second spinal cord stimulator, both by Medtronic. Both of them are rechargeable so a bit different than that model. The reed switch is there for the same reason as a pacemaker has one, so emergency personnel can shut them down if need be. Mostly these things run nonstop from the time they are installed. On the controller you can set the strength of the pulse, did I mention they pulse, anyway the strength, the length and the pulses per second. They do have a clock in there somewhere as they will shut off 10 years to the day they were turned on. I know this as my first one, which was working beautifully at the time, shut down and I spent an agonizing two months without stimulation waiting on the doctor to implant another. In my case, chronic back pain with shooting pain down the left leg, this device covers around 40-60% of the pain and has cut my opioid consumption by over 2/3. It is a wonderful device and I can’t say enough about the Medtronic company. Having it implanted is a semi barbaric procedure as you must be awake for the placement of the leads and they can’t deaden the area either because you have to be able to feel it and tell them if the stimulation is in the right spot or not. Oh, and each lead has several (6-8) electrodes on each, you only use two on each lead at a time. By energizing different leads they can “steer” the stimulation to cover the areas of pain.

[___sudo_c__]

Doing research on these pacemaker/neurostimulator.. Never manage to open one of them. It's really good to see this video. Thanks!

[HeyBirt]

I've had one of these in me for about I years now. Truly an amazing device. The first ones that came out years ago had no internal battery. They were inductively powered via an external antenna/coil. The one I have is rechargeable, which is done inductively, about every other week. The sensation is sort of like an external TENS unit and at times can be annoying and can last for a few minutes after turning the device up. The latest units operate at a higher frequency that you can't feel but that still interferes/masks the pain signals. These operate in burst mode taking advantage of the effect lasting after it is turned off. These are not rechargeable, the battery lasting about 10 years.

[kenwolfe]

stimulator can be turned off or on with a magnet. It's a lot faster than waiting for the programmer to negotiate communications to shut it off or turn it on. Mine has 20 contact points connected to the electrode assembly in my middle back (spine) so they can tailor the effect. Mine is also rechargeable using a non contact coil. Thanks Dave!

[henryD]

I have a Medtronic pacemaker implanted about 6 years ago. Initially the batt life was estimated at 11 years. A year ago it dropped to about 9 yrs. It "paces" only about 1% - 5% of the time. (Could be above 70% for some.) PM keeps LOTS of data (mem is cheap). It's checked every 6 mos using electromagnetic communication to small device and Bluetooth connection to phone app.

[krakerjako]

Been watching too much AvE, when Dave said "focus!" trying to show the laser trimmed resistors I automatically said "you fuck!"

[scottfirman]

I have one in my body right now. I found out it didnt work effectively. Its been in more than 10 years, time to get it removed. I have a chronic pain issue from a kidney cancer surgery that went bad. I havent activated it in years. Glad you did a tear down .thanks.

[cityslacker]

Hey! I've been an EEVBlog subscriber for years and I have a Spinal Cord Stimulator implanted. Love this teardown. Mine is Boston Scientific Spectra. My EE professor and I had some fun discussing what kind of circuits it must have.
I will write up my experience and come back and post it.

[Arnthorg]

Would be awesome if you would send the ASIC to electronupdate for decapping

[--Zook--]

My wife has been using medtronic insulin pumps for almost 20 years. Not implanted but external. They have continued to get better and better to where they are pretty much a artificial pancreas. Her meter tells the pump what she needs and it delivers. I know there is more advanced versions out there that do more but for her it works great.

[xxxxx]

God that battery is terrifying. I had a bad experience with a thionyl chloride battery once. It was a little 14250 and the guy needed a couple solder tabs welded onto it. I work at a battery store BTW. I thought "eh welding to lithium is dangerous but screw it" so I put on some safetly glasses as it was a button top and those always pop and shoot molten metal everywhere. Welded the top just fine. Took the glasses off and did the negative POP lots of sparks. I moved it to check the weld and get sprayed in the face. Thankfully I wear glasses normally. I would have lost an eye for sure as I watched the spray hit my lens on my right eye. This stuff is nasty! It becomes Hydrochloric acid when exposed to moisture/air and its a VERY exothermic reaction so not only did I have a temperature burn but a chemical burn across from basically my right temple to my left jaw line. What hurt was it pooled up in the crease between my nose and cheek. Oh and this stuff makes it very hard to breathe especially when its right under your nose. That was not a fun experience but we are all good now, no permanent damage and I learned some stuff.

[hansenrl]

Wow, this was interesting to watch. My wife has VNS implant to control her epileptic seizures ... a Cyberonics unit. She had it replaced about two years ago and she was allowed to keep the old unit. Looks a lot like this one. EDIT: On the cable ... when you have the unit replaced (to replace the battery), the lead isn't removed as well unless it's damaged or showing loss of conductivity. Instead it's simply detached from the old unit, and then attached to the new one ... hence, not having one to look at. We got to see them when we toured the manufacturer in Houston TX, and they are unbelievably small. Remarkable they can not only flex as much as they do without failure, but they can withstand being used over and over.

[JMMC]

I've found you'll go through less dremel wheels by making sure you go *really* slowly, with minimal pressure. You get much more cut distance per wheel than if you try to rush.

[jeffreymurdock]

I have a neuro stimulator implant for my back. Had it implanted in 7/2019 but it's a different brand and is rechargeable wirelessly. It's a big help with my messed up back and the pain it causes.

[judsonanderson]

Hey Dave, my dad actually has a spinal cord stimulator from Medtronics that was implanted right around 2004. From what I know it has four parts.

1) The remote that he carries with him everywhere. This allows him to adjust the current going to different leads to help mask pain more appropriately.

2) The battery pack. This is implanted under his skin and he's actually going in to see about getting a new battery this year. It's roughly square and you can feel it in his back in the love handle area.

3) The stimulator unit. This is similar to what you tore down.

4) The leads that run from the unit to the nerves. These are very small but it lets my dad move around and get as much out of life as he can.

From years of talking with my dad, each unit adjusted to each patient after they have been implanted, but they can't even get to the permanent implant stage before having a trial "implant" where the leads run out of the skin to an external system that is housed in a purse or "fanny-pack".

An interesting aside is that about four years after my dad had his implant, it randomly spiked in delivered current one day while he was riding in a car. The best the doctor could figure is that is was likely triggered by something like a garage door opener.