[sharman]

Amazingly enough, I have one more long part to this already interminable piece. This part will talk about combining ADCT and PDN with other therapies. (May be split up, due to post length limits)

First, three apologies. 1) Sorry to take so much space with this. If you're getting sick of it, imagine how I feel. 2) I apologize for not taking the time and energy to post sources, and figure out how to link on this forum. If there is any info here you would like sourcing for, just ask, and I'll be happy to dig it out and post it. 3) "PDN" is strictly speaking a brand name used by Raymedica for its nucleus replacement products. But I know of no generally used acronym for "nucleus replacement prostheses," so there, that's the term I've glommed on to.

So getting to it:

There are four possible complementary therapies: (i) endplate abrasion, (ii) selective endoscopy, (iii) thermal annuloplasty/ablation of granulation tissue and (iv) biologic agents. These therapies were discussed in the thread "Can you Heal a Disc?"; this post will talk about how and if they can be combined with ADCT or PDN. Finally, there's a small section on further developments and issues with ADCT.

Combining therapies is not entirely wild-eyed speculation on my part. This is from the website of Spinewave, the company that makes NuCore, one of the injectable hydrogel PDNs:

"On going efforts are characterizing the use of the material as a cell-delivery vehicle for disc repair and reconstruction. Related development efforts are exploring methods for repair and regeneration of the cartilage endplate that are implemented to enhance the host-implant interface. Prior to the introduction of the above-mentioned bio-material, our work proposed to utilize a process for the treatment of the vertebral endplates. The goal of this process is to restore the endplates as closely as possible to their natural state prior to disease or degeneration. The nature of the treatment will depend on the type of scaffolding that is intended to be introduced to the nuclear cavity. Endplate therapy is a potential means of enhancing biomaterial integration and cell survival, but remains a long-term and currently untested methodology."

I Endplate abrasion

So let's talk endplates. So-called "Mdic changes" (named after the researcher who first identified them) are often seen in patients with symptomatic DDD. There are three types of Modic change: Type I is inflammation/edema of the endplate; type II is replacement of the bone with fat (indicating that the inflammation has been of long duration: type I morphing into type II) and type III is bone sclerosis, hardening of the bone ("as the body tries to heal the damaged disc, extra bone cells are formed.") Degenerative changes in the endplates may contribute to the pathology of DDD by compromising the nutrient/waste/water exchange between the nucleus and the endplates.

(And/or, the endplates might themselves be pain generators. At this point, my eyes have well and truly rolled back in my head--I don't have the strength to consider another pain generator. If the endplates are the pain generators, you wouldn't think an ADR would fix things, would you? Seems that having a keel chopped in it, or cleats nailed into it, would exacerbate rather than ameliorate such a pain source.)

Hoogland at Munich's Alphaklinik has been doing a procedure he calls endplate abrasion, where he scrapes the endplates to remove calcification:

"The calcified bone of the adjacent vertebrae is refreshed by means of special fraises and sharp spoons, in order to acheive a better blood circulation. The now vital vertebral bone will grow new tissue, eventually restoring the schock-absorbing qualities of the intervertebral disc."

Hoogland has just published results of a 66-patient study, and claims excellent results for patients with Modic 1 changes (80% good or excellent), versus 40% good/excellent in Modic II. Back pain of 5 years or less duration also correlates with better outcomes with this procedure. Hoogland claims to acheive observable re-hydration three months following the procedure.

So, in theory, endplate abrasion would appear to complement both ADCT and PDN (although there is no more living nucleus requiring a healthy endplate, PDN does require the ability to uptake and expel water through the endplates, so abrasion (or other endplate therapy--SpineWave would not divulge much about the "process for the treatment of the vertebral endplates" that they are investigating) might improve this function.

Important caveats with respect to combining abrasion with ADCT: Abrasion is invasive; introducing this into the treatment plan somewhat cancels out one of the biggest advantages of ADCT, the minimal trauma. While it is sorely tempting to find a way to boost the effectiveness of ADCT (my gut feeling, that it is the least likely therapy to work, and will require a very healthy disc to start with), I would have to be very convinced of the benefits of abrasion before accepting the additional risk.

II Selective endoscopic procedures

Yeung speaks of using his visualized endoscopic procedures to see and remove parts of the nucleus that have degenerated, and also "interpositional disc tissue" he finds stuck in annular tears. It is thought that the 'interpositional tissue' prevents the tears from healing, or serves as an irritant. How the presence of degenerated nuclear material contributes to back pain is not clear to me, but perhaps this study suggests the mechanism: "The high levels of proinflammatory mediator found in disc tissue from patients undergoing fusion suggest that production of proinflammatory mediators within the nucleus pulposus may be a major factor in the genesis of a painful lumbar disc." Maybe degenerated (necrotic?) material creates or exacerbates the inflammation.

Hoogland combines these endoscopic procedures with his endplate abrasion.

Again, adding invasive procedures to an ADCT raises the risk level. For PDN, the nucleus is entirely removed, so that's a moot point, but as long as they're in there anyway hauling out the NP, it may make sense to look at the tears and make sure anything stuck there is removed.