Can you heal a disc?

[sharman]

This is a subject I've given a lot of thought to, and have had some significant results exploring.

Please forgive the long post, and any factual errors. This is all just based on my imperfect understanding, from what I have learned or misunderstood along the way.

Let me say first off, I think these procedures will likely only work for discs that are still relatively healthy--have good height and relatively intact annulus. So, it may not be of interest to ADR candidates. On the other hand, it may be a way to address levels still responsive to such therapies, thus limiting the number of levels needing ADR, and/or eliminating sources of pain that are not considered appropriate for ADR.

My understanding is, discogenic pain--low back pain originating from the disc--is probably coming from tears in the annulus. Only the outer third of the annulus is innervated, so that is the only part of the disc that could be generating pain.

So how to heal an annular tear?

IDET

One approach is IDET (or similar procedures, like Dr Yeung's SED), in which the tear is heated, causing the collagen fibers of the annulus to seal up (I am probably describing it badly). That procedure had uneven results, and is not something I personally would pursue.

DISC INJECTION

Prolo solution

This is an injection procedure that I have tried, with significant results For want of a better name, the procedure is sometimes called "prolotherapy to the disc." If you have never heard of prolotherapy, it is the injection of a dextrose solution near an injured ligament, to strengthen and tighten it. The dextrose acts an irritant, causing a localized injury that stimulates the body's normal physiological healing response, resulting in the formation of scar tissue. I have had prolotherapy done, and it does do what it says it does, you can feel it. (Whether prolotherapy can help back pain is another subject.) I credit prolo for correcting some wobbliness from too much chiropractic.

Here are links to two published studies of disc prolo. one study other study

A disc is made of collagen fibers, virtually the same as ligament tissue. So, the reasoning behind disc prolo goes, why not inject the prolo solution (dextrose) into the disc, to induce healing of the annular tear? I have had this procedure done, and I truly think it works. The improvement is not as dramatic as an ADR or fusion, but for me it was significant and much appreciated.

The theory of induced healing may sound far-fetched, but the improvement I got came on over a three month period, consistent with organic healing. It lasted a long time, until I started putzing around with other procedures. Unfortunately, while the first two disc prolo injections had positive results, additional injections (I had the fourth about a year ago) have brought on a side effect that has worsened my situation, namely, that my back is now sensitive to pressure, as a result of which I am unable to tolerate my previously comfortable back chair.

Growth hormone/stem cells, etc.

Somewhat similar to the disc prolo is injection of other materials designed to kickstart healing. Stem cell therapy seems the obvious, likely future direction here. The Microspine clinic recently tried injections of "precursor" stem cells (hematopoietic cells), but reported no positive results. It's not clear if the intended target in the Microspine study was annulus or nucleus tissue or both.

There is now a study in Los Angeles looking into intradiscal injections of growth hormone. I think it's worth checking out, free if you participate in the study. And despite my mixed experience with a similar therapy, I think it's relatively risk free.


Can therapies aimed at the nucleus help?

There are also a number of therapies aimed at the nucleus. So what is the role of the nucleus in discogenic back pain?

The nucleus is not innervated, so is not itself a pain source. Its material is caustic, and can cause chemical (as opposed to mechanical) back pain, if leaked out through an annular tear onto the nerve root or other innervated tissue. Perhaps replacing the nucleus with a prosthetic works by eliminating the caustic matter. But, would nucleus replacement have any value for mechanical back pain?

Given that the outer one-third of the annulus is the only innervated part of the disc, I continue to believe the annular tear must be the source of the pain. What role does the nucleus play in this pathology? For we do know that nuclear degeneration is a common feature of DDD: Just as we can see the annular tears on the CT scan, we see the black disc--degenerated nucleus--on the MRI.

My guess, degeneration of the nucleus may be responsible for annular tears not healing by themselves. The annulus does not have a blood supply; it gets its moisture and nutrients by diffusion from the vertebral endplates through the nucleus. (Not surprising that the disc, with such poor prospects for self-healing, is a common source of chronic pain.) So, is there a therapy or prosthesis that can make the nucleus serve more effectively as a transporter of nutrients to the injury?

Nuclear replacement

According to an exhaustive report of new spine devices coming to the market spine industry report , some new nuclear replacements devices are indeed designed to mimic the nucleus' function of transmitting nutrients to the disc. The Raymedica PDN-Solo, for example, is designed to "restore physiological function of the nucleus by osmotically absorbing and emitting fluids, allowing a fluid transfer between the vertebral bodies." Another device employing a hydrogel, the Neudisc, claims "The hydrogel's ability to rehydrate itself mimics an important characteristic of an intact nucleus pulposus [namely, pumping up at night, and pumping fluid out during the day]... The "pumping action" of the hydrogel closely mimics the nutrient cycle that is constantly ongoing in a natural disc." "The value of the Neudisc and PDN hydrogel technology is the ability to mimic the intact nuclear material's ability to "uptake" water, continuing the nutrient cycle through the vertebral endplates."

Raymedica claims patients report as much as 70% pain/function improvement, with 80% reporting improvement. (Manufacturers' stats, of course)

By contrast, non-hydrogel devices (e.g., the DASCOR, a polymer that is injected and expands to fill the patient's disc space, curing in place), seem to only mimic the loading and flexibility properties of the nucleus, not its permeability. "[The DASCOR is] designed to treat DDD by simulating the physical structures in the nucleus and restoring disc height."

The hydrogel PNDs sound very encouraging to me, perhaps paired with therapies directed at the annular tissue, discussed above.

Autologous chondrocyte transplantation

In this therapy, cells are taken from the patient's nucleus and cultured in a lab, then re-injected. This therapy can be done in conjunction with a discectomy (to correct a herniation), and is also being studied as a low back pain therapy. Perhaps the procedure reverses degeneration in the nucleus, restoring function. study

There does seem to be a limit to the effectiveness of this therapy, at least in theory. In one brief article I read, researchers elected not to pursue this therapy, due to the "senescence" of the cells used for culture. If I understand this correctly, this means the cultured cells would be effective to restore nuclear function, but would have a limited life span. Still I say, if the therapy gave you two or three good years, it would be well worth it.

Here again, it would seem that stem cells may be the future. Senescence should not be a problem with stem cells.

Endplate abrasion

Alphaklinik does a procedure where they abrade the endplates, on the theory that it is calcification, etc. on the endplate that stops the flow of nutrients to the disc. Other than AK's website, I have read nothing about the efficacy of this procedure.

So

What do you think?

[mmglobal]

Sharman, great post.

IDET: I think that the great acceptance it received years ago is pretty much gone. It is good in theory and there are some happy patients running around out there - as well as some unhappy ones too. I've been in the OR for IDET procedures. The thing that bothers me about it is that it's blind. The surgeon can see where the wire is with flouroscopy, but has no way of knowing what is happening as the energy is being applied. I like the idea of thermal annuloplasty for some cases of discogenic pain with good remaining disc height, but IDET would not be my first choice.

SED: I've attended the surgeons' training for Dr. Yeung's SED with thermal annuloplasty and have seen many SED surgeries. I really like the targeted approach. He can see the tissues that he's removing. I love the way he stains the nucleus with indigocarmine and can identify degenerated tissue from healthy tissue. When he's applying energy with the laser or RF probes for the thermal annuloplasty part of the procedure, he's looking at the tissue he's working on. He can see how it responds. If the annular tear is shrinking as he's heating the annulus, he keeps going. If it's going in the wrong direction he stops. I know many SED patients including many failures. Remember that these types of minimally invasive procedures are done in the hopes of salvaging a degenerated disc and avoiding more invasive surgeries. I would have been a perfect candidate for SED before my ADR procedures and I wonder if I'd have metal in my back now if I knew about Dr. Yeung years ago.

Nucleus Replacements: I've seen many different nucleus replacement technologies brought to the market in the last few years. I've been in the OR for some implantations. It is all interesting technology... especially the new flowable procedures where they inject a flowable polymer that fills the disc space and provides cushioning in addition to maintaining the disc space. It will be interesting to see how this all plays out. So far, nucleus replacements don't seem to have lived up to the hype about them, but as the problems are solved and the technology improves, I think they'll get it right.

Many of the less invasive procedures do depend on being applied before the DDD is too great. However, when they can perfect annulus repair, in conjunction with nucleus replacement or regeneration, that will eliminate or reduce the need for total disc replacements. I've seen several different versions of annulus repair and they look promising. It's still early, but again... they'll get it right eventually.

Endplate Abrasion. I posted about this last month (here). I got to spend some time in the OR with Dr. Hoogland and question him about this procedure. It makes sense that improving the flow of water and nutrition between the vertebral body and the disc will help slow the degeneration of the disc, or potentially even rehydrate the disc. I believe that there is evidence to show that it can happen. However, I'd like to learn what percentage of the cases it will happen in. Is it most of the time, some of the time, rarely? I believe that Dr. Hoogland is a world-leading endoscopic surgeon and if I need endoscopic spine surgery, he's one of the very few people in the world that I'd consider.

With most of the minimally invasive procedures, I believe that if what you need is a discectomy, then going to someone who does a superior MISS discectomy, you stand an excellent chance of success. As always, the diagnosis is key... determining what you need and then going with the least invasive procedure that stands a good chance of resolving your problems is the best way to go. This is said knowing that a substantial number of people will still graduate to more invasive procedures... that doesn't mean the less invasive procedure was the wrong decision, even though in their case they will wish that they skipped that procedure and got out the big guns. But without the motivation to try less invasive procedures, there would be no success for them, and many more problems associated with more invasive procedures.

I have little experience with prolo, intradiscal prolo, many other types of intradiscal injections, etc.... except for the failed patients I've seen who have graduated on to ADR surgery. I've scrubbed in on lumbar disc replacements with patients with a many different types of past treatments. For the most part, these treatments seem to have seriously disrupted the disc nucleus tissue. As I mentioned above, it has a different consistency, texture, color, density... Note that people with successful treatments are not seeking me out and are not having further spine surgery. The population of people I deal with is a self-selecting negative population who have failed prior treatments. I cannot draw conclusions about the efficacy of treatments that I see in the failed patients.

I started seeing Bertagnoli's presentations on autologous chondrocyte implantation several years ago. It looks very promising, but in this treatment, it requires an intact annulus. When the disc herniation is removed, they go into the disc and harvest more healthy nucleus tissue. That is sent to the lab where they culture more of 'your own tissue'. 3 months later, they pressure test your disc and it must hold 200 psi for 15 minutes. (I'm typing this from memory... I may have the numbers wrong. 200 psi sounds high to me as I never see pressures that high in discography.) If your disc will hold pressure, they inject 20 times the number of cells that they harvested. I've seen films of post-op patients who's formerly black discs are white at 2 years out. Is this the norm? I don't know. Is there a huge buzz about this at the conferences? No. I'm headed back to Straubing in a week... I'll talk to Bertagnoli and see if there is a relevant update.

Mark