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#11
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There is a hefty body of knowledge of how long term loading affects elastomeric materials. If they've done what they're supposed to, and I can't believe they wouldn't, the loading on the elastomeric disk will stay low enough that there shouldn't be any long term damage in the bulk material. It shouldn't compress or tear.
My problem, and Laura's doesn't completely agree with me so you can tell it's a pretty fine distinction, is with the bonded joints. When you design a test plan for a device, you try to mimic real life but you also make assumptions about what parts of real life gets mimicked in your test plan. We don't have a good model about how bonded joints fail in fatigue so it's difficult to make sure you've made the right assumptions. It looks like real life loading for a spinal disk is now sufficiently well understood that there's not a whole lot of assumptions left to worry about but consider me a conservative engineer. I wouldn't tell people to get M6s taken out or avoid them under all circumstances but I would suggest that the marketing claims about how good the M6 are could be a bit too ambitious.
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Laura - L5S1 Charitee C5/6 and 6/7 Prodisc C Facet problems L4-S1 General joint hypermobility Jim - C4/5, C5/6, L4/5 disk bulges and facet damage, L4/5 disk tears, currently using regenerative medicine to address "There are many Annapurnas in the lives of men" Maurice Herzog |
#12
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Well that's interesting to hear what you've got to say re engineering knowledge of elastomers.
Sort of going way off topic here but I've got the company (glossy) literature on what they exposed them too for their testing, basically 10million flexion extension (but it was only mild imo, 7.5 degrees or so) and 10 mil in lateral under 120N. At the end they required a lot less force to compress them, but it was still in the range or thereabouts of a real disc and they lost up to 2mm of height... a huge amount in my view... the company line laughable compared it to biological disc height loss under load... but they rehydrate. Anyway that's a fair flogging for them and at the end they were still working. On that long term study of the charites a lot of them had auto-fused (which is the natural history really) so that may save a lot of strife in old age with adrs. One thing which stood out to me is they stress test them in neutral, but once you install the disc it is in segmental extension due to lumbar lordosis. So a lot of unknowns and like most things the true test is time... so fingers crossed everything is sweet and if the end comes it comes quick, heart attack in sleep sort of thing.
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Dec 2010 L4/L5 M6 L5/S1 ALIF |
#13
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Hooch,
We don't want you to go in your sleep! Maybe it makes a difference to take it easier. I'm thinking maybe we disc/fusion people shouldn't ski, horse backride, etc. Dr. Zigler told me not to do anything that would have a constant banging motion. (he used horseback riding as an example). Don't cross your fingers, prayer probably works better
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L5-S1 Lumbar M6 by Nick Boeree 10-14-2011 |
#14
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Vicki,
Did Dr Zigler mention running? Thanks, Jeff
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C4/5 - ACDF in 2000 C5/6 - ACDF in 2002 C3/4 & C6/7 - M6 ADR, Nov 2009, Barcelona Conceded defeat to a manifestly disingenuous BCBS-TX in my quest for reimbursement, Jan 2011 |
#15
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Oh well I just got back from a light run. My surgeon pretty well says dont bungee jump, parachute or deadlift heavy weights. Others will say never lift anything heavier than a pot of beer.
Probably more important to balance your spine and musculature... learn how to move in neutral... pilates... it's all very complex and a lot more work than just avoiding activity.
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Dec 2010 L4/L5 M6 L5/S1 ALIF |
#16
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When I asked him if there is anything I shouldn't do, it was pre op. I'm not sure about long term, but I will ask if he meant right away or indefinitely. I just asked my hubby how he took it and he thought the Dr meant short term. He did tell me that since we have a pool, that will be a good choice.
For me personally, I'm not going to risk anything that might endanger the disc. I figure nothing is as good as the real deal. Artificial disc is called that for a reason. It might help to take pain away and give you some freedom back but I'm not going to look at my ADR to give me a free pass to try anything and see what happens. I'm just a bit more coservative at this point.
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L5-S1 Lumbar M6 by Nick Boeree 10-14-2011 |
#17
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Quote:
I completed an 11 mile run just before I posted that question. I try to use my pair of M6-C's in the same way that they were tested; that is I try to hold all unfused cervical joints below the atlanto-occipital joint in an extended position when I run. That way the my M6-C's get stressed in a very similar fashion to the environment in which they were tested. I hope that's Ok for my remaining two natural discs. I'm impressed that you've managed to return to running after a lumbar ADR.
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C4/5 - ACDF in 2000 C5/6 - ACDF in 2002 C3/4 & C6/7 - M6 ADR, Nov 2009, Barcelona Conceded defeat to a manifestly disingenuous BCBS-TX in my quest for reimbursement, Jan 2011 |
#18
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Activity post-ADR
In the military, they have you running, jumping, fully-deployable with no physical restrictions after 3-6 months post-op with the ProDisc-L. I can only imagine the second-gen will be similar. Some surgeons are going to be overly cautious, others may not be restrictive enough. Trust me, your body will let you know when to slow down. When it hurts, when you feel discomfort, then don't do it. Some days, for me, that means I don't leave my bedroom. Other days it means I can go for a walk in the park (keep in mind, I'm only one month out).
The Freedom, which just finished trial surgeries here in the US, but is available in Europe, I believe, underwent stress testing and did not show wear, if I remember correctly. There's a DVD I've linked to in my sig that shows the testing they put it through (more than 5x what the human body is likely to put it through) and it came through with great results. Some doctors are PAID to endorse certain discs over others, so keep that in mind, and make sure to ask your doctor if he's recieving any financial boon for using one disc over another. They are required by law to inform you if they are.
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Surgeon: Dr. Kenneth Pettine @ The Spine Institute, Loveland, Colorado Freedom vs. ProDisc-L Trial Participant 2006: Initial disc herniation/spinal injury at L4-5, L5-S1 2007: Physical therapy and manual chiropractic rehabilitation to manageable level. 2010: Fall down flight of stairs, re-injury. 07/20/2011: L4-L5 Freedom ADR Surgery Facebook Me |
#19
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Yeah if you are pain free or more commonly pain significantly reduced, eg your op is successful then returning to activity is something you can choose to do or not.
I looked at the military too Azhure as I know they are all about returning personnel to active duty, and they have no qualms about putting people back in post disc replacement or fusion. Not that I'd look to the Military as some benevolent organisation that looks as your body as anything other than a tool, but it is pretty well purely focused on function. I chased up one study where they did PLIFs for US army infantry with ddd (about 12 or 20 people or something like that) and they got 80% back to active duty. Jeff not that I want to hand out a heap of unwanted advice but I'd keep your cervical spine in its neutral position and worry more about your natural discs than your artificial ones. Maybe by extended you mean neutral, I reckon you'd go back to neutral soon enough regardless doing long distance running or your neck would be giving you some curry. Chris.
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Dec 2010 L4/L5 M6 L5/S1 ALIF |
#20
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Great responses
Hi everyone again!
Thanks for more great responses and things to think about. I'm still struggling with this microdiscectomy/ADR question. Has anyone here had a large central herniation and had a successful/unsuccessful microdiscectomy or did you go straight to ADR. The three surgeons I met with here in San Diego (all amazing surgeons) have recommended a microdiscectomy but have been very guarded about the outcome for me. Do they try to underpromise and overdeliver or are they just being realistic? I don't know how much better my life would be with just reduced leg pain... My back hurts pretty bad... I consulted with Nick Boeree and he is really cool, suggested I go to ADR because microdiscectomies rarely do well in my situation. Is there anyone else you guys can suggest consulting with that is on the cutting edge of spine surgery that can offer all the options? I can't wait to build my body of knowledge and give back to this community. Thanks again!!!
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Lots of high impact athletics, large central extrusion L4/L5 at 30 years old. Back and Leg Pain became unbearable and could not walk. August 2011 Successful Microdiscectomy with Dr. Leary in San Diego. Leg pain is completely resolved but still dealing with back pain, researching ADR and Fusion again so I can live life to the fullest. Lumbar Level L4/L5 Dr. Clavel 12/10/2014 |
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artificial disc replacement study, spinal arthroplasty contraindications |
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