Spinal Kinetics M6 - A Shock-absorbing Artificial Disc with "Graded Resistance"

[Tyler]

I'm a biologist and work in the biotech industry. I'm also an active 48-year old and was really concerned about choosing the best artificial disc available for my particular condition (severe foraminal compromise and disc degeneration at C5-6 and C6-7). Although other discs have been used longer, after researching what I could and following up with nine different surgeons in the U.S. and Europe, I decided to go with Spinal Kinetics' M6-C (picture below).

Besides being designed to match the normal motion or kinematics of the spine, the core (which is meant to provide functional features of healthy discs) has several important attributes that closely resemble those of nature's originals:

1 - there is a central core or nucleus that is somewhat compressible, as in the healthy disc, and therefore capable of absorbing and cushioning axial load rather than just transmitting it to adjacent regions - but is not so compressible as to allow the intervertebral space to be restricted

2 - there is a ring or annulus surrounding the nucleus that facilitates freedom of motion but in a restrained fashion, as in the normal disc

3 - the internal structure of the annulus provides "graded resistance to motion" (i.e. more resistance to motion as the turning or bending motion increases) - this again mimics the native disc and could be important to help restrain the disc from over-extending (e.g. in an accident or other stress situation), and could help to protect the facet joints which might otherwise be impacted by over-extending motion (this contrasts with most ball-in-socket designs since the ball is typically able to spin without being internally restrained)

4 - the overall core (nucleus + annulus) is surrounded by a flexible non-load-bearing collar that should tend to keep any outside materials/cells from getting into and around the core (cell intrusion and in-growth can eventually lead to reduced rotation or auto-fusion observed with many discs); also, in the event that any microdebris eventually wore off the core as can theoretically happen with any disc, it should be held inside by the collar (this again contrasts with ball-in-socket designs and other discs in use since these generally do not have a containing collar, nor would it be easy to do so with a spinning ball)

There are of course other considerations - and every patient's situation is in some ways unique. But I decided to go with technology that appears to be among the best available - mostly because it seems to closely mimic what nature has already evolved, and what the surrounding structures are 'designed' to work with.

Just as important is finding a great surgeon who's experienced with the disc. In this case it was harder because I'm in the U.S., and although M6 was in clinical trials here (and I met with one of the key docs involved), it's only available outside the States. After a lot of searching and talking to patients, I felt fairly confident about going with any of the following three leading M6-users in Europe: (1) Ritter-Lang at the Stenum in Germany; (2) Nick Boeree at Nuffield Wessex Spine Clinic in the UK; and (3) Pablo Clavel in Barcelona.

I ended up going with Nick Boeree and had an absolutely amazing surgery - and results - details here:
http://www.adrsupport.org/forums/f47...6-tyler-10743/

Besides thanking Spinal Kinetics' engineers and my docs, I also want to thank folks here at ADR Support for the very helpful contacts and info.

If I can be of further help to anyone, please don't hesitate to ask!

Best,
Tyler

[Tyler]

Attaching further thoughts from another thread, in reply to some good points from Rob Wilson:


Originally Posted by Rob Wilson
This disc seems amazing for its simulating a real disc. I have had so many adjacent issues such as piriformis, SI joint, ligaments, etc that I would love this disc. However as a M6 for the lumbar I am scared if it would last. With 4 different parts and 4 different materials and with the lumbar having so much more load and torgue I would be scared of it. I liked the simplicity of the 2 part all steel Maverick. Any thoughts? Thanks

Hi Rob,

First of all, I'm a biologist not a bio-engineer; and secondly, it's not clear how any disc will really act over very long periods of time within the setting of the spine.

That being said, I do think you're right in valuing simplicity. But I also strongly believe that an ideal for anything put into the body, especially something implanted within a system of 'moving parts' like the spine, is to follow as closely as possible the native structure and mechanics.

I would add that besides basic durability of the cores (which are evaluated by stress-testing in the lab with both applied loads and millions of movement cycles), other issues that are known to be important include the potential for wear microdebris from the core getting outside of it, cellular inward access to the core with potential for auto-fusion, and last - but definitely not least - the relative impact of the implant on the adjacent structures. It also seems that the discs, although they can have modest cushioning capability, are still largely transformers of load than bearers by virtue of the surrounding structures incl. bone, ligaments and muscle.

My bottom line is that every spinal implant is in a complex environment and choice is a balance of projected durability (based on load testing) but just as importantly weighing how the implant interacts with the overall mechanics of the spine. In fact, the nature and 'quality' of interactions within the local environment would seem to be even more important if other parts of the spine are already affected as they are in many cases.

IMHO...

Best,
Tyler

[Rob Wilson]

Tyler,

I was just curious how you found and chose Dr. Boeree?

[Tyler]

Originally Posted by Rob Wilson

Tyler,

I was just curious how you found and chose Dr. Boeree?

After researching procedures and discs and talking to a number of surgeons and others, I eventually looked for docs having experience with M6 (and preferably also other devices) and then communicated with both them and patients.

As you know it's always a hard decision, and ultimately a hunch. But after consulting with nine different surgeons, and following emails and a couple of phone conversations with Nick, I got a good sense of his responsiveness and care (although that isn't to say it wouldn't have worked out well with other docs I was considering). Secondarily, the hospital at Eastleigh was quite pleasant and the interactions were smooth. Couldn't really have gone any better.

[wgnmn]

Tyler, I spoke or rather contacted you while you were still in England. I talked with Dr. Boeree today, he called me after I paid $ 380 by credit card in order to have a 1/2 hour discusion with him. I think it was worth it. You did that twice???? And did you get charged like that ? Do you think it would help monetarily if I let the Dr. know that I'm part of this community?

Anyways, I met with Dr. Scott Bluementhal at the Texas back Institute , and He said he would only do a 2 level fusion for me at c5-6 6-7. Dr. Bertagnoli was willing to do a 4 level with the Pro Disc C nova. (3-4 and 4-5 aren't in the best shape ) Sooo, do I go conservative or agressive? I'm leaning to conservative do to the fact that there are always improved adr's coming out and if I need another one, with "ONE" being the key word , for insurance to possibly cover it down the road. Who knows, based on what is happening with our health care lately.

Trust me, I had pro's and cons from Bertagnoli,( rather Tim his moderater ),for the ( Pro Disc) and Dr. Boeree for the M6. I'm going for the M6 but have to wait for pricing before I commit. After it's all said and done, it will be very interesting to see how long they last. Thanks, Todd

[Tyler]

Hi Todd,

It seems that most consultants and certainly those in the U.S. charge a fee, although in my opinion, consultations with experts that you can really discuss issues/suggestions/concerns with (especially after you've done some research) are really worth it. In that regard, I ran some of the concerns you apparently heard by other docs, several of whom I believe are among the most expert in the field, and they either did not agree with the concerns or believed they were more likely to be an issue with ball-in-socket discs, which are only partially constrained (or rather more constrained than native discs in some directions and then unconstrained in others).

I think there's also a mistaken suggestion that compressibility means the M6 disc would allow the spacing to be collapsed (almost like loose shocks in a 'gangsta' car). I had it explained by docs with experience in the testing that it's graded resistance, with modest compressibility resembling that of the native disc. And having had the ability to play with actual M6 discs when I did the in-person consultation in England (pictures in my photo album), I could actually experience what they mean first hand. The compressibility is more like that of a properly filled tire, i.e. not much, but it does provide shock resistance because of the nature of the materials, and the contrasting 'treads' that allow some motion but resist it more as motion increases (again like nature's design).

Let me know how things go - rooting for you all the way!

Best,
Tyler

[Tyler]

The posts in this new group The M6-ers include a number of surgical outcomes from folks who are now 'part-M6':
http://www.adrsupport.org/forums/groups/m6-ers/

[jwestglass]

Tyler,

I am considering an M6 lumbar for L3-L4 and have contacted the same 3 you did. How did you decide to go with Dr Boeree. I know Stenum is a big "operation" no pun intended
and the other two are more independent. Was it the number of procedures they have
done that pushed you one way or antother? Thanks for the info....john

[Tyler]

Originally Posted by jwestglass

Tyler, I am considering an M6 lumbar for L3-L4 and have contacted the same 3 you did. How did you decide to go with Dr Boeree. I know Stenum is a big "operation" no pun intended
and the other two are more independent. Was it the number of procedures they have
done that pushed you one way or antother? Thanks for the info....john

Hey John,

You can see reports and talk to folks from each of the three European centers mentioned (and I talked to all) at the M6-ers group:
http://www.adrsupport.org/forums/groups/m6-ers/

After you've talked to as many prospective docs and patients as you can, it's ultimately a hunch. But as you and others have asked, here are some thoughts on Nick Boeree:

Regarding experience, for complex surgical procedures such as these and where every patient’s situation can present special challenges, I think what's most important is breadth and quality of experience, and attentive care, rather than high volume per se. That being said, with respect to artificial discs, it’s my understanding that Nick has not only performed hundreds of ADRs over the years, but has extensive experience with a number of different discs, including ProDisc, Charite, Mobi-C and M6. Although he's not connected with any particular company, he liked the design and functionality of M6, and several years ago became the first UK surgeon to employ M6-C and is among the leading users of the device. On the lumbar side, he used Charite and ProDisc but is now a key user and evaluation center for the more recently introduced M6-L device. He’s also highly experienced with other devices (he was a developer of STALIF-TT anterior fusion cage and was lead clinician for the international study of the Wallis Dynamic Stabilization technique) – as well as highly complex spinal procedures (e.g. reconstruction and revision surgeries).

Besides talking to prior patients and others (which I did), personal interactions and being focused on detail were also key factors in making my decision. His intelligence and care quickly came across in conversations, and gave me a lot of confidence that I was in great hands for a complex surgery - and that he would be both prepared and highly focused to deal with whatever the actual situation presented once it was fully revealed. In that regard, he doesn't use others to 'assist' so I was his sole focus the morning of my surgery - and he doesn't generally do more than two such surgeries on any day.

With all of these things, I felt pretty good in making my decision, and more so after talking on the phone and later meeting in person. I felt even better (about him and the disc) as soon as I woke up, with my fingers feeling completely normal and none of the arm pain I’d had for months, and very little operation site discomfort. I’ve now been off of pain meds completely since Day 2 post-surgery, and have already recovered much of my lost arm strength. I may have been a good case but I don’t really know how it could have gone any better.

Bottom line, I'm a firm believer in talking to as many experts as you can - and being direct with questions as you go. It takes effort but it's worth it. In the meantime if I can help in any way, don't hesitate to ask.

Best,
Tyler

[Tyler]

Going on 5 weeks post-surgery and still pain-free, so keeping to a previously-planned trek in the Himalayas - and yes I will be careful...!
Since there are no kerosene-powered routers, I'll be incommunicado till mid-Oct. but wishing everyone the best!
Ty