Scheduled for C5/6 ADR with a Prodisc-C--questions about that type of implant
 

Hi there! I'm excited to have found this forum. I suppose this is probably the spot to put my long-winded intro. I've had chronic neck/shoulder issues since a significant roll-over car accident in 2011--did plenty of PT, etc, no real help there. Spring 2015 I started having severe muscle spasms, and by May 2015, I got that horrible tell-tale pain down in my right forearm, along with numbness/tingling in my thumb, index, and part of my middle finger.

After months and months of running around between orthopedic doctors and physical therapists, I finally forced the medical director to authorize an MRI, and low and behold! Disc problems. Here's my MRI summary, in case anyone's curious:

C4-5: Mild posterior osseous ridging which is eccentric to the left. Mild left-sided canal narrowing. No cord compression. Neural foramina patent.

C5-6: Disc-osteophyte complex with element of left paracentral disc protrusion. Moderate canal stenosis. Mild left ventral cord contouring without cord compression or cord edema. No significant foraminal stenosis.

C6-7: Shallow central disc protrusion without significant canal stenosis or cord compression. Neural foramina patent.

I got referred to a pain specialist, and after months of waiting, got in to see a neurosurgeon as well. The pain specialist I saw first wanted to try some cortisone injections in C6-7, just based on reading the MRI report. I was going to do that, but I lucked out and got in to see a neurosurgeon early before that appointment. The Neurosurgeon looked at my actual MRI films, and thinks my issues are mostly from the C5-6 level, and said that he thinks I should have an ADR surgery to fix that issue. Especially because of the bone spur at that level, he said there’s little chance that disc will ever stop being a problem on its own, and I’m young (32 year old female). Seemed reasonable to me, since I’ve been ready to just cut my own arm off.

He also said that a disc replacement would decrease the chance of speeding degeneration at other levels, so long as insurance will pay for it. I am still a little concerned that the disc below it, C6-7 is already bulging—he obviously didn’t think it should be dealt with surgically yet, but I’m still worried about it, since the pain specialist actually thought that disc was the problem. That’s making me nervous.

After having my pain disregarded for so many months, I was taken by surprise when the neurosurgeon suggested ADR, and I knew absolutely nothing about that surgery. I was unprepared to ask questions. I called back later and asked what type of disc they were going to use, and the staff told me it would be a Prodisc-C. I wanted to ask more questions directly, but unfortunately they would not let me speak to the surgeon over the phone. I scheduled an appointment to speak with him in person, but they're so booked up, that appointment is only three days before the surgery itself!

In the meantime, I'm concerned about the type of disc he's using. As I understand it, the Mobi-C is the only disc that's approved for use at two levels. My concern is that although it's not surgical now, I already have a disc that's herniating beneath the one that they're replacing. I'm concerned that in the future I'll need that one done as well, so I'm worried about having that older Prodisc in there.

I work in academia, and I spend a bunch of time combing through journal articles--so naturally I spent some time reading through the literature on various types of ADR models. The issue seems to be that most of the studies are comparing different types to traditional ACDF surgeries, not to each other, so there's not a lot of robust research to really say oh, well, Mobi-c is definitely better than the Prodisc-c etc. I found a few that compared them, but they were in a lab setting, not actually in human bodies. This is probably too much for one post, but here were some of the things I dug up:

Overall, across several studies I found, the Prodisc has good results over a 5-7 year period, with little risk of implant failures so long as it was placed properly. It may have a slightly higher risk of heterotrophic ossification, but most of the implants seem to have that same problem, and it's not totally clear if the Prodisc's design has anything to do with that higher risk. Furthermore, heterotrophic ossification didn't seem to cause adverse patient outcomes anyway--it's like the devices just slowly convert into a fused disc, as I understand it, and fusion in general also has high success rates.

In lab tests, it appears that the Prodisc does a better job of protecting against extreme forces/excess movement, because it has a more constrained design than the Mobi-C. However, the polyurethane core wears down and starts shedding plastic particles more quickly than the Mobic-C (not proven in a body, just in a lab setting).

The only thing I found about the Prodisc that was worrisome is that there is a potential risk of a vertebral body fracture, due to the way they cut the bone to insert the big keels. But, this risk should be mitigated by them implanting it correctly, and not putting it in people who are not good candidates (small vertebrae, significant osteoporosis, etc). This risk does increase if you have a fusion OR another Prodisc implanted in an adjacent vertebrae. Interestingly, there are studies of Prodiscs being used at multiple levels, so it IS a possibility (although not FDA approved). It just carries that added risk. And that added risk concerns me. It was unclear about if they could put a different type of disc in the second level, and what the consequences of that might be.

Sorry about that long, long introduction, but basically I'm hoping for some other perspectives on my issue, and about the Prodisc-C itself as a device. There's only one surgeon in my area that does the Mobi-C that's on my insurance, and for practical reasons, waiting until summer to sort out another long chain of referrals is going to be difficult for me. As it stands, I'm scheduled for the ADR with the Prodisc on February 29th, and that's the most trouble-free option, but I don't want to make a mistake letting someone put this thing in me!

Is there another forum I should put a more condensed issue of my question in? Thanks for your help!

Bad news, you've pretty much caught most of the concerns. One additional one that has come out over time is that the Prodisc can permit hypermobility and lead to facet damage.

Good news, to some extent the vertebral fracture potential can be reduced by confirming bone density ahead of time and working with a skilled surgeon. Doesn't make that concern go away but it does reduce it. The hypermobility concern can also be partially addressed with strength training (once you're recovered to the point where that's safe). Laura's had two Prodisc-C's and uses strength training and prolotherapy to address the hypermobility.

Overall, it's pretty difficult to evaluate one ADR against another. Partially because most of what we accept as their attributes is actually marketing hype and partially because there's been little head-to-head testing or evaluation. As you're in academia, you'll understand that studies are generally only done when the study author is likely to be funded to do it. My, frequently expressed, opinion is that the most significant factor leading to ADR success is the surgeon's skill, not the ADR. If you feel like you're being railroaded, especially in that you can't speak with the surgeon, that's probably a far better indication that you need to delay and get your worries addressed

Well said, AnnaPurna. :)

JinSong, no, this forum is fine and thanks for asking. Let me know if you need help with this:

http://adrsupport.org/forums/showthread.php?t=11053

I've got a signature saved--is it not showing up? Thanks for adding me to the forum!

Thanks for your input! Yes, that's exactly what I found, in that there's almost no literature comparing the different devices together in vivo, and I assumed that was probably likely due to funding issues. It also makes sense in that at this point, with insurance companies in the US still fighting against ADR, that the research efforts are mainly trying to prove that ADR is equal to or superior to ACDF (and cheaper--found some studies arguing that it's cheaper in the long run). Meanwhile, I'm like I don't care what's cheaper, I have to live with this thing in my neck!

The Prodisc is concerning me still, especially with the whole two-level issue. The communication problem, as you mentioned, is also disconcerting. I actually really liked my surgeon, and he has a good reputation, but it just seems like we have so few surgeons in this town that they're all extremely busy and hard to get ahold of.

I may post another question about this, but I was also wondering about clicking issues--I've read a few posts here and other places about the Mobi-C making very loud clicking noises, and I'm wondering how common that is. I've seen fewer complaints about that with the Prodisc.

Jin,

Thanks for adding your signature. :)

The clicking noises are usually (if not always) attributed to structural adjustments of soft tissue post-operatively. Not sure if that would include facet joints (Z joint) or not. But in regard to your question, I don't think I've ever read a post from a patient (since 2004) that decisively stated that the clicking was from a poorly placed ADR.

Yes, complications have occurred; I am only addressing one of your specific questions.

Well, in that case it's good that it's not attributed to any specific disc type!

As I'm waiting to see if I can push through more appointments for second opinions, I had sent my MRIs and history off to Barrows Brain and Spine Institute in Phoenix, Arizona (feel free to delete that info if giving out names of facilities is not okay) for a remote consult. I didn't know that such a thing existed, so that was a nice discovery. They won't discuss surgical options, but at least they can confirm that you're a surgical candidate. I'm waiting to hear back from them though, because they interpreted my MRI a bit differently--I think they may have just made a typo in the disc levels! In case anyone's curious, this was what they came back to me with:

After careful review of your films the MRI imaging demonstrates a moderate
left para-central C5-6 disc herniation with compression of the spinal cord and mild
compression of the outgoing left C6 nerve root. There is a smaller left para-central disc
herniation at C4-5 without spinal cord deformity or significant impact on the outgoing C5 nerve
root on the left side.

The recent onset of left arm symptoms may reflect a structural change at the level of the spinal
cord and nerves or could simply indicate that the left C6 nerve root is becoming less tolerant of
chronic compression.

You are certainly a surgical candidate given your progressive symptoms, spinal cord
compression, and lack of response to physical therapy.

I'm guessing they meant C6-7 instead of C4-5 because as far as I knew from my other appointments...all I have at C4-5 is a bone spur. I emailed them to confirm, but regardless, I think the lesson here is that MRIs can be interpreted in different ways by different professionals. In this second consult here they seem to be much more concerned about the spinal cord compression, which was not really noted strongly by the original MRI report. The first surgeon mentioned a potential for permanent myelopathy in the future, but didn't really stress what's already going on there now.

Hypermobility of ProDisc, but also I would say new COR on axis of spine not the same as well as lack of translation.

The hypermobility problem seems like it's a well-known issue, which definitely concerns me.

I'm still harassing neurosurgeons, but thus far the soonest consultation I can get from anyone that uses a different type of disc isn't until almost April, just for an initial appointment. Now I have to decide whether to go through with the Prodisc surgery in February, or throw the dice and wait to see if/when I can get in with a different surgeon. Not an easy choice!

I'm so excited, because after weeks of harassing various surgeons in the state, I managed to get in for a third opinion TOMORROW. I was so worried I was going to have to make a choice between doing surgery and waiting for several months for more info/options from another surgeon. Will update after that.