Is there a disc less prone to injure facets? Keel vs. non?

[ans]

Hi Folks,

Is there? I hear good things about the Active-L but dunno if it's for public consumption yet.

Also, if one needs a revision, does it make sense to get a non-keeled on versus a keeled one?

The reason I ask is b/c my MRIs show "moderate" facet damage and even if my facet injections don't help me I'd wonder about facet compromise w/ADR down the line.

Thanks and be well. - Allan

[sharman]

If the operated level is easily accessed, like L5/S1, I wouldn't be too worried about the keel vis a vis a revision. The few reports I've read about revisions on keeled discs, they appear to be easy enough to remove, if accessed from the anterior.

I think the Activ-L is available in the US through clinical trials now. Allan, do I correctly recall that money is an issue for you? That might be worth looking into. It's used in Europe of course, and Canada; I like its design. This disc is available with or without a keel.

[sharman]

I hate bad grammar. "Anterior" is an adjective, not a noun. Let's make that "if accessed via an anterior approach"

[ans]

Thank you Sharman. My pain's getting worse and I'd probably have fusion at the L5-S1 level and ADR at L4-L5 (or more pending a discogram). I just get the creeps at the L4-L5 level as revision's complicated by blood vessels and scar tissue. Hmm, wonder how long Active-L w/be approved in the States. (Money is an issue but extensive DDD knocks me outta trials - thanks). You take care - Allan

[mmglobal]

Allan, activ-l is many years away from approval... they are still enrolling. (Regan did a client of mine in the clinical trial a few weeks ago.) They'll have to wait until ALL enrollees are 2 years post-op to begin packaging the data to submit to the process... my guess is that it will be More than 3 years.

The facet answers are not known. There are competing biomechanical studies that are all interesting exercises, but the results are conflicting. I also believe that some people will benefit more from a stationary core device and others will benefit more from mobile core devices. I don't think that we'll be able to tell who is who in advance... by the time we know, this crop of devices will be obsolete. I don't remember what your films look like, but if your facets are headed south, it may be the case that waiting has already had more impact on the potential outcome than would the choice of prosthesis.

As to your original question... I don't think that the keel has any impact whatsoever on facet issues. Placement... biomechanics (of the device AND your spine) will determine that. Keel is for ease of implantation, resistance to migration, subsidence, and maybe some other issues that I'm not remembering in my very tired state. It comes with advantages and disadvantages. IMHO, it's not one of the more important factors in the decision. (That is based on NOT using a device with a HUGE keel, like the original Maverick... that's a whole other story.)

How 'moderate' are your facets? What have the ADR surgeons said?

Mark

[Maria]

Hey allan,
I'm sure I'm doing myself no favors by waiting this out re facets at the L5S1 space but what I worry about is at L4 and knocking myself completely out of the ADR category by waiting.

My back has gone out more frequently (quite a number of times since Oct.2007) tho recovery is quick. The traveling and/or tiredness of my spine is now creating a sort of mild burning moderate tiredness feeling in my calves that makes me want to lie down to relieve. It is relieved but is happening too often. I feel like I've done far too much walking when I've done none but the feeling is related to bumping around too long with travel, or being upright too long without enough movement (walking)~ and then again, there's this cumulative effect it appears.

Why don't we just plan to have our surgeries around the same time so we can drive Mark nutz together?

[ans]

Thanks Mark for your reply. My MRIs since 2002 have indicated "moderate" (once even worse than this) facet damage but Drs. Regan and Lauryssen told me that ADR is OK - although I have not seen them in about a year. Regan said if you decide on surgery to get facet injections again. Great that this wait has probably pushed me into the fusion corner, not.

Maria: If we have surgery at UCLA, we can be roomates! Feel better!

Wouldn't it be great if there was absolute knowledge re: ADR, etc.

[sharman]

Allan, I am sorry that your condition is so bad. Still, the fusion/ADR hybrid looks like a good surgery. You get the ADR protection for the rest of the spine, and at L5/S1, you are not trying to force an ADR where fusion is the better choice (and once less level for facet worries). You have every reason to hope for a good result.

I agree with you, a keel at L4/5 poses real concerns. A keel could make things more difficult if you ever need the device explanted via a lateral approach. Of course, if you need a lateral-explant revision, you're in trouble already. I am hopeful on two fronts, tho. First, that post-Charite discs will have fewer complications requiring explantation. When I tried to google information on ADR revisions, I found many reports of Charite revisions, but few for the Prodisc. Second, that new surgical techniques and materials, like the Goretex barrier, will make anterior access feasible.

The question is, do you see advantages to the keel, and how do the advantages compare with the revision risks? Your anatomy may dictate the choice. On the Activ-L website, they say the keel should be used where the endplates are so deeply concave that the prosthesis can't make good contact.

Good luck with this.

[ans]

Hi Sharman,

Thank you for your words and advice. I think I'm forming osteophyte bridges at the L4-L5 level but do not know re: concavity. Nor did I know about the Gore-Tex! Great information and and again thanks. ans