Greetings from Munich (AlphaKlinik room 905). I'm still in running the marathon that I do on these trips, but the last surgery was yesterday... hopefully I'll get more time to spend here soon. (It's Saturday morning and I've been here since before the surgeries started yesterday.)
This study is interesting. I've been seeing Bertagnoli do ProDisc-C procedures for more than 3 years. I've been seeing presentations about many different systems, now for the last 4 SAS and NASS meetings. I will see if I can get some perspective on this result.
I found the classification system that was referenced in the study. An article that references the system is posted here:
Advances in Disc Technology.
Note that this article is from 2002, but I believe that the system they are talking about. Here is an overview of the grading system:
- Class 0: no heterotopic ossification (HO)
- Class I: islands of bone in soft tissue, bone not present between planes formed by the endplates
- Class II: bone present between the planes of the endplates, but not blocking motion
- Class III: motion blocked by HO and/or postoperative osteophytes
- Class IV: inadvertent bony ankylosis
"A member of the audience raised the point that the presence of HO may not correlate with outcome."
I know dozens of patients with prodisc-C and know ZERO with HO problems. (I suppose it's possible that some have Class I or II HO but it's not been discussed as a relevant issue.) Also note that my experience is with patients who are all less than three years out.
Look here for much of the data that was presented regarding the Charite.
http://www.cms.hhs.gov/mcd/viewdecisionmemo.asp?id=170
Search for heterotopic and you'll find charite studies with fairly large numbers and enormous percentages of HO... > 50%, as high as 80%. Horrible results! However, in the hundreds of charite patients I know, HO has only been an issue in extreme cases and for the most part, it's in people that should be fusing and autofusing represents a good result. (The HO patients that I know can be counted on one hand, without using 1/2 of your fingers.) IMHO, what we are seeing here is that early in the process with new devices, there will be a huge difference in outcomes depending on surgeon and technique. Early in the process, the appropriate techniques are not fully developed. I remember when there was a ProDisc surgeon in the Bay Area who was telling patients that his lumbar ProDisc experience was, "1/3 got better, 1/3 stayed the same, and 1/3 got worse!" Again... horrible results... but that is not the experience with the device across the board and there are surgeons who's outcomes far exceed the mean... just as there are surgeons who's results come no where near the mean.
I wish I had time to write more. This is an important discussion. It really shows why I'm always skeptical about data and studies. Many patients go through the process of searching for the Holy Grail of data and studies and evidence based medicine... only to be discouraged (and sometimes kept for seeking treatment) by finding things like this. I'm not suggesting that we should ignore data and studies... just don't panic... take your time and find out... dig deeper than what the paper says... dig deeper than what your doctor says.
All the best,
Mark