Alastair, thanks for the post. I've had several clients with subsidence... some minor and some severe. As Alastair mentions in his post, some of the most horrible looking configurations can still be excellent results. (Unfortunately, we see the flip side can be true, with excellent looking configurations producing poor results.)
I've had several clients get vertebroplasty AFTER disc replacement surgery because of subsidence that was discovered many days later. If memory serves me correctly, Doreen's was done inside of a week post-op. Another client of mine had vertebroplasty done inside of 2 weeks post-op. I’ve also had a client who received prophylactic vertebroplasty during ADR surgery, but still experienced subsidence. This turned out to be a minor problem for a few weeks. The subsidence was minor (presumably thanks to the vertebroplasty.) I can only imagine that it would have been much more serious without the vertebroplasty.
I've had extensive discussions with dozens of leading ADR surgeons over the years. Subsidence is thought to be an early complication... if you don't get it in the first few weeks, it won't happen. We all talk about the potential for developing osteoporosis later in life and experiencing subsidence, but I have not seen reports of that. (I've been attend ending several major spine conferences for years and in May, I'll be at my 5th Spine Arthroplasty Society annual congress. If cases were presented, it would have been at SAS.) After being in the OR and seeing a very fit man in his early 40’s, with zero reason to suspect bone density issues, but who had very poor bone quality, I came home… called my doctor and asked for a bone density test. I’ll do one every 5 years now… just to make sure that if I discover a bone density issue, it will be with a test result…. not with a serious problem in my spine.
One serious, but rare risk that will always (*see note below) result in subsidence is a dorsal fracture. If the back of the vertebral body breaks as the prosthesis is being inserted, it can go undetected. The structure required to support the prosthesis is too seriously compromised. If the dorsal fracture is discovered in surgery, the surgeon will be aborting ADR and will fuse. In the cases I've seen of dorsal fracture, explantation of the device was necessary and fusion was done.
I know 2 surgeons who’ve attempted to ‘jack up’ a subsided prosthesis. The vertebroplasty cement does set very quickly. They hoped that they could lift the prosthesis and support it in with the cement. Neither will try that again. With their experience, they will attempt to arrest the subsidence and not allow it to get worse by supporting the prosthesis with vertebroplasty. They cannot reverse the subsidence with vertebroplasty.
While vertebroplasty seems very straightforward, but like most things related to spine surgery, it is complicated and there is a huge learning curve. I’ve seen it done by surgeons with little experience with it. I’ve seen it done by surgeons with great experience. Getting it to flow where you want and not to flow where you don’t want it is critical and it takes practice. Knowing where and how to apply it is not as obvious as it seems and technique varies greatly from one surgeon to the next.
The good news about subsidence is that in most cases, it will stabilize. The subsiding prosthesis in its unstable configuration is very painful. However, when it the bone starts supporting it properly and it becomes stable, the bone pain goes away. That does not mean ignore it… but it does mean don’t panic. If I had subsidence, I’d get a bone density test. There would be many factors in the decision to get vertebroplasty… do I have access so someone with experience? How severe is it? Is it advancing? I’d monitor it closely and I’d not be jumping around or lifting heavy objects until I was sure that everything was OK.
There is so much more to write… many more details, but I can’t now. I hope this helps.
Anyone with spine problems should feel free to call me…. number on GPN and iSpine websites.
Mark
* note... I'm not a doctor. I'm relating what I've learned through the years from spending a great deal of time totally immersed in spine. I assign higher weight to what I've learned from the doctors with the most experience and the best technique. I often get conflicting information from multiple surgeons that I trust. What you get from me is my understanding, colored by my experience. What I write may be incorrect... it's up to the reader to determine the value of what I write. It could be gold... could be worthless... most likely somewhere in the middle.
|