Facet Vs Sacroiliac Pain
Today I would like to talk about the most important thing that influences the outcome of certainly endoscopic spinal surgery, but in this case any surgery, and that is simply making the correct diagnosis. I have talked many times about spinal pain mapping, but today I want to introduce something that I stumbled across many years ago, which is kind of a little variation of spinal pain mapping that I call functional pain mapping.
Spinal Pain Mapping
Typically in spinal pain mapping, as you all know, you would be taking the person, have them come into your office or surgery center, and actually inject them maybe one thing at a time. For example, a facet if they have some back pain, and then they would go on home and they would report back to you a week or so later, and you could ask them how it went.
The problem with doing it this way is twofold: One, you do not really know what happened to that block early in the game. For example, if they had some very recalcitrant facet pain and you injected the facets, you would not know if they had relief immediately post injection and the pain returned after a day or so. So, that is one problem. The second problem is that typically these injections are done in fast order and then the patient is just left. There is no attempt to actually put the patient in a position where they actually had their pain or their pain bothers them. Those are the two shortcomings of blocks I think in the way they are typically done.
So, let me first tell you about functional pain mapping, something I kind of stumbled on when I realized these shortcomings several years ago, and it really has worked out well. The way it works is to sedate the patient, and by this I mean the anesthesiologist or nurse anesthetist sedates the patient with some propofol while the needles are in place wherever you want them. For the facet joint I know some people block the joints themselves, but I am here to suggest that getting inside a facet joint is not that predictable and not that easy unless you are using a CT scanner. So I think that blocking the nerves, the dorsal primary nerve branches, is maybe a better block; and also if you are considering a rhizotomy, maybe a more predictable block of what the patient will experience post rhizotomy, if you are going to do an endoscopic rhizotomy, say for example with the Wolf vertebra set. So, you have sedated the patient and then you do the block. The propofol is reversed, the patient wakes up in a few minutes. I then examine the patient within 5-10 minutes of the block, and I ask them two questions: 1. Can they get into the position that they were hurting in before, and, 2. What percentage of the pain is relieved immediate post injection? The patient requires a little coaching to do this. They have to know before you start the process that one, you are going to ask them what is the most painful position that they can get into so that they can get into this to actually test out whatever position it is. This is the functional part of it. The second part is to ask for a percentage. So, if a patient just says “well I got 25% relief of my pain”, that is not really adequate for me. I am looking for 75% to 85% relief of the pain within about 10 minutes of the block. I consider that to be significant and positive, and it is what I refer to as functional pain mapping.
Let me give you an example: In the films that I am going to show you here, the blocks were first done on the facet joints. This is a 52-year-old woman who had pain with extension. She had been in the airline business and had a lot of bending, stooping, and lifting requirements throughout her career and found that this pain in her back was fairly paracentral, at least it seemed to be fairly low back. I thought, ah no kidding, gotta be facets. So I took her to the operating room, and she actually was able to extend her back and re-create her pain. I took her to the operating room, put the propofol, put the facet blocks in as shown here, and then let her wake up and let her get into the positions that aggravated it, within 10 minutes of the block in the operating room. She said, “that didn’t really do too much for me.” I was actually kind of surprised, but she said it did not do much, maybe 20% or 25% relief. I consider that to be a no go; so that is not effective. I said, “OK, let’s get on to plan B” which in her case was the SI joints bilateral, both of them; and you can see the injection here really is near the posterior-superior iliac spine where she has kind of kind initis of sorts. It is really what I call tennis elbow of the pelvis, and in blocking these, going through the same process, letting her get up off the table, let her do extension, crunching forward, crouching, the pain 100% gone within less than 10 minutes. I consider this to be a positive block, and for her the whole concept of facet syndrome is out, and I would say that she has bilateral sacroiliac joint symptoms.
OK, I hope this is a good example of the differentiation I would make between spinal pain mapping and functional spinal pain mapping, and I hope to show you this example in a few other cases that we might do.