Carlos.

Some really interesting points. I am no discography expert myself (maybe somebody out there is who can help?) but skimming the literature suggests disagreement regarding how sharp a test it is. In the Peng study report it appears that the injection may have been delivered at the time of discography or at least that’s how it reads to me. However all people in both groups will have had a positive discography and so the follow-up would just include 2 groups of people who have been told the same thing.

I guess the reason I find it so surprising is that we’ve known that discs undergo changes for a long time but in the good longitudinal data it doesn’t appear to have much influence on the course of the problem.

As for the eccentric loading in tendinopathy thing it is a very popular therapeutic movement at the moment but I’m not sure the quality data can be considered conclusive yet. Take this from a recent systematic review on Achilles tendinopathy management (http://www.ncbi.nlm.nih.gov/pubmed/19124985) :
“Eccentric exercises were noted to be equivalent to extracorporeal shockwave therapy (1 study) and superior to wait-and-see treatment (2 trials), traditional concentric exercise (2 of 3 trials), and night splints (1 study). Extracorporeal shockwave therapy was shown to be superior to a wait-and-see method in 1 study but not superior to placebo in another.”

So conflicting evidence for the superiority of eccentric exercise over another exercise approach and equivocal effects with a therapy that appears not to outperform placebo.

If the results of the Peng study are right it suggests that in these patients the chronic pain is being driven primarily from the bottom-up rather than the top-down. I guess I have got used to not thinking about the problem in that way. As for the central neuroplastic changes one might expect in a chronic pain patient – well we don’t know enough but perhaps a plastic system is more dynamic and adaptable than we might give it credit for. Of course all of this speculation is putting the cart well before the horse of independent replication, and I would agree with Prof Bogduk that we need to see that before doing too much reappraisal.

I have never observed a discography which means I may be inaccurate in my initial thoughts. Are the people within this particular study being diagnosed with discogenic pain in a somewhat different manner than the normal discography procedure? Baogan Peng has been focused on this particular type of research since at least 2003. The following link might be the initial work leading to the current work being discussed on this site. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2198898/?tool=pubmed I do not have access to full text of the article shared on the blog, but I will assume the methods in determining discogenic probably didn’t change. Peng described a 2 part process in defining discogenic. So, if the definition of how discogenic is determined is the same as the earlier work, is this definition standard across the world?

I’m interested in the timing of the person learning of the results of the discography, the explanation of the findings and when the injection occurred after learning the discography results. I can literally visualize the “bad” disc. The reason I am interested in the timing is because we have literature indicating how how test results and the description of what was found can increase fear and anxiety. I’m thinking there could be potential differences in results if the findings were shared and an immediate injection occurred versus the findings were shared and then having to wait to be scheduled for the injection and then waiting for the injection after the procedure was scheduled.

Baogan Peng also reports differences between degenerative discs due to aging versus painful discs versus normal discs: http://www.ncbi.nlm.nih.gov/pubmed/16508552 And if the differences aren’t notable via MRI, another reason for failed back surgeries and poor outcomes with surgical procedures: http://www.ncbi.nlm.nih.gov/pubmed/15329231

In an odd way, Peng’s work is almost paralleling what Peter Andersson is mentioning with some conditions of the Achilles tendon – the altered neovascular structural changes.

So, two things come to my mind (as a physical therapist) – the tendon can be altered to be normalized with eccentric exercise and the subjective complaints can be substantially reduced. So what about the intervertebral disc? Is there some way to normalize the neovascular changes or prevent the neovascular changes? The other question – the biopsychosocial factors… someone having pain for more than 6 months – what’s the scoop with that aspect? How was there not a higher percentage of non-responders? The central changes and pathways being utilized for 6 months or more just went away magically?

Quite thought provoking work…

~Snippets

@ Bronnie,
Even if the results are replicated it doesn’t kill off the biopsychococial model, it just indicates that there is a subgroup of patients with chronic back pain who when identified by discography can be more successfully treated than we have ever seen. In saying that a recognition of the non-biological would still represent a mature and holistic treatment approach.

@ Mike. Thanks for the link. I saw that fascinating paper on the detrimental effect of discography. Striking as the effects are they don’t tell us whether the increased disc degeneration was related to an increase in symptoms or a change in the clinical picture. Given the poor relationship between disc state and outcome in other studies I wonder how concerning these findings are? I dunno?! In relation to your chosen approach to management it certainly sounds reasonable but unless it is shown to outperform other approaches in well controlled trials I guess we don’t know with confidence that it is a better solution.

@ Peter, there seem to be lots of different injection based approaches to tendinopathy right now. Once again I await the reliable RCT data with interest. Uncontrolled clinical studies tend to be cheeky monkeys that overestimate effects. If anyone is a little sceptical about the need for RCT’s read this fantastic story from the career of Bill Silverman (something of a hero) here: http://www.jameslindlibrary.org/essays/cautionary/silverman.html
Or this fabulous editorial recently in the spine journal on vertebroplasty here: http://www.ncbi.nlm.nih.gov/pubmed/20207329 (sorry for linking to pubmed but I find the sciencedirect links don’t seem to work later on).

Thanks again all for your comments

Intersesting, kind of same treatment as in chronic pain in Achillestendon, inject a substance that kills nerves and vessels. In Sweden Aethoxysklerol is used quite succsessfully according to the clinics that do it…
Exentric load of the tendon for about 3 months works as well…No one knows why but it 6 out of 10 get well…

Best wishes, Peter