Choosing ADR or fusion

[sharman]

I am considering whether to do ADR or fusion at L5/S1. I probably wouldn't consider fusion at all, but for this being a single level, and the level where (I believe I've heard) preserving motion is least critical. Some of the new minimally invasive fusions look to me a lot less traumatic than ADR, tho surgical trauma is only one of many factors to consider.

There are a million points on which to compare the two procedures. I am mostly laying out the questions here, and will really appreciate hearing any thoughts or information you have.

Both procedures should be equally effective at eliminating a discogenic pain generator, as in both the symptomatic disc is completely removed. (Or does ADR leave a piece of the annulus in place?--that always bothered me.) So the questions are,

(A) What are the risks of each procedure/device.

I see five main categories here, the first three being the most common: Damage to (1) adjacent discs (advantage ADR over fusion, which puts increased stress on adjacent segments); (2) facets (a risk for ADR, less so for fusion?); and (3) nerve roots (from the surgery=equal risk in either ADR or fusion? Perhaps the new fusion technique, approach through the sacrum, offers the least neurological trauma. trans1.com.) The choice among these first three risk factors might be dictated by what each patient considers most vulnerable in his/her own body.

Also to be considered is how fixable each of these three problems is. (1) No one wants more discs to fail after major surgery to correct the first failure. But at least we know discs can be fixed (fused or replaced). (2) Pain from damaged facets appears much more difficult to relieve. Nerve ablation is painful, hit-or-miss and must be repeated when nerves grow back. There appears to be one interesting treatment, cryotherapy, but I know little about it. (3) Nerve damage is also difficult to fix, though frequently resolves in time. The treatment, drugs, is not a pleasant one.

(4) The fourth category is damage to structures other than the three listed above. In fusion, there is a risk of hardware loosening or otherwise causing damage, any one know of any others? In ADR, there is the risk of subsidence, poor placement, etc. Osteoporosis is a risk for ADR, is it also for fusion?

Is the trauma done to surrounding tissues and bone worse in ADR (cleats or keel, major abdominal surgery) or fusion (pedicle screws, removal of bone both in the spine and elsewhere). One of the biggest disadvantages of fusion in my mind is the need to harvest bone, with the resultant complication of donor site pain. I do not know what strides may have been taken toward eliminating or diminishing that risk.

With fusion, if the segment does not fuse, where does that leave the patient, and what are the options?

The big question in my mind is an issue I'll call fit, for lack of a better term. Patients come in all sizes, ADRs only come in a few sizes. Do some ADRs turn out badly because the device did not fit well? Is fusion inherently more likely to fit each patient's anatomy? Or do the cages/whatever inserted into the disc space, or the screws, used for fusion also create issues of fit.

Should a patient's body type influence the choice? I have a gut feeling that tall, long-waisted people do better with the ADRs, perhaps as a direct result of the difficulty of fitting or implanting the device in us short, dumpy guys.

(5) The fifth category is long-term and unknown risks. In ADR, there is the risk of the device failing (like artificial hip joints), and the unknown effects of particulate wear from the device. Fusion has a lot of problems, but it's a known commodity.

(B) What are the implications for future surgeries, or revision?

Advantage to fusion here? You burn bridges having that major abdominal surgery for ADR, scarring down the blood vessels so that the approach cannot be used again. Now one thing I do not know, does that mean only that it is now more difficult (or impossible) to access the same level from the abdomen, or would it affect access to adjacent levels too? A not remote issue, as one can foresee needing surgery on L4/L5 some years after an ADR at L5/S1.

(C) What are the relative discomforts of the surgery and recovery?

It should not be a deciding factor, but it's not meaningless, which procedure is more difficult to go through and recover from.

Some of the minimally invasive fusion techniques appear to be easier to go through than ADR. Certainly, it would be nice to avoid abdominal surgery. The incisions are smaller. The new trans-sacral fusion claims to have patients out of the hospital in one day, and back to work in 15.

On the other hand, your new ADR is ready to rock and roll from day one, while a fusion must fuse, over several months' time. At the least, that probably means one's activities are more restricted, and corsets must be worn longer and more faithfully.

One issue on the comfort list is advantage to fusion: The possibility of finding the surgery you want in the US. For ADR, there remain many things not available here, like the newer discs and vertebroplasty compounds.

Any thoughts most appreciated!