PATIENT AWARENESS DAY 2018: LIVING YOUR BEST LIFE WITH ENDO
Sunday, March 18, 2018, (8am-5pm) Einhorn Auditorium (131 E76th st) at Lenox Hill Hospital, NYC
Spinal Interventions for Pelvic Pain
Gerard DeGregoris, M.D.
- Thank you very much. Good afternoon everyone. Thanks so much for the invitation today. I think this is an important topic to consider, thanks. And I just by way of introduction, so my name is Gerard Degregoris and I'm a board certified anesthesiologist. So my background comes from general anesthesiologies, with an emphasis on the physiology of the body and especially how the peripheral nervous system, interacts with the central nervous system, because in anesthesiology we really have to understand how procedures and medications interact between the two parts of the nervous system. Because from a surgical perspective, when surgeons are doing things to peripheral nerves peripheral nerves are firing and producing pain. So we need to figure out a way to modulate some of those pain impulses from the central nervous system to in the operating room, produce what we call anesthesia. And one of the components of anesthesia is pain control. And for this talk we'll be focused on specifically how interventional, usually needle based procedures can mitigate the painful symptoms, that ordinarily would go and be perceived by the central nervous system. It's all about modulating how those pain symptoms are generated and how they get conveyed to the central nervous system. So we'll talk about some spine interventions for pelvic pain. Just by way of context. We're not gonna talk about all these things here, but I wanna just sort of start sort of panning out so we can see what are all the different needle based interventions and then how does my part of it fit in. So some of these things you've heard about already for instance from Doctor Shrikhande's talk earlier. So there are things like muscle based injections which you've heard about, peripheral nerve blocks, regenerative medicine which is sort of an exciting rapidly developing area, which includes things like platelet rich plasma, includes injections of alpha 2 microglobulin and more and more injections of stem cells. So that's what else is out there. And then this last bullet, is what I'm gonna spend most of the time talking about here, which would be spine interventions. And for the most part, the things that are most applicable to patients suffering from endometriosis would be sympathetic nerve blocks, and we'll talk about what that is and epidural injections as well. So any time we're gonna talk about spine interventions, the first thing is to understand, what are the spaces that we're talking about. And what are the structures that we're talking about. So, this picture here is a stylized representation of what the spine looks like. This would be a cross sectional view. As if someone had sort of cut me in half, sort of right along my necktie area. And what you see is the left side of the screen there would be the structures closest to your abdomen, although behind the abdomen obviously. And the right side of the screen there would be the structures closest to your back. And, I think, let's start in the middle. If you look at the spinal cord there, that yellow structure in the middle. Not actually yellow but this is a cartoon. That's where most of our nerves are, most of the important nerves are gonna be that convey the vast majority of information from the environment up to the central nervous system. The central nervous system then processes that information and then sends other, mostly commands out to our body, so that our bodies can react to our environment. To manipulate our environment and to manipulate our body to interact efficaciously with our environment. So the spinal cord is where most of those nerve segments live. It's surrounded by a protective envelop called the dura, and if you've ever had surgery and had a spinal anesthetic, the dura is a sack and you poke that sack, and that's for instance, how a spinal anesthetic is delivered. And that's a very potent way to deliver anesthesia, for instance, for certain surgical procedures. Now outside of the dura lies the epidural space, so epi meaning around, or in close proximity to, so epi dura, around the dura, and that is a space that usually doesn't have a lot in it. There are usually some blood vessels, there's some fat in there, but it is a dispensable space, so you can use that to your advantage, in medicine we will sometimes put medications around the dura, thereby getting some of the benefits of exposing very potent medications to the spinal cord but not having to actually violate the dura, and there's some safety involved in not violating that dural membrane. So many of the things we do, both in anesthesia and in pain management, involve putting medications close to those important nerves that we talked about near the central nervous system. So epidural injections. So if we're going to do an epidural injection you would then violate, you'd take a needle and go through the skin in between the spinous processes, which are the slanted down bones there. And once you get through the spinal processes a few other ligaments there and some muscle, the last one would be the interspinous ligament, and after that we cross that interspinous ligament we're then in the epidural space. So when you hear about people getting epidural injections that's the space we're talking about. So that's just to put things in perspective, now that's for epidural injection. Sympathetic injection, we'll differ a bit here for another slide, so let's talk a bit about epidural injection first. So, these injections are increasingly performed for patients with pelvic pain, but not all patients with pelvic pain. So like we've heard of earlier today, there's many different structures that can create pain and can contribute to the experience of pain. And if we think that there's a problem in the epidural space, so if we think that the part of the problem is coming from nerves that are inside the spine, one convenient and very safe way to get into the spine is to give an epidural steroid injection or local anesthetic injection through what's called the Caudal approach. It's known as a Caudal epidural. So these two X Rays here are representative X Rays. So the one on the left, you have to imagine that the person is kind of standing sideways. And what you're looking at is the base of their spine kind of how I am to you now and you can see at the very bottom would be the tailbone. And there's a black linear structure there which is an epidural needle. So in this patient the physician has taken the needle and accessed this epidural space via the Caudal approach. Which is a convenient place, because by this point the spinal cord has ended. So the most sensitive part is really not around, and it's very difficult to cause damage to it if it's not close by, and yet, that epidural space is still accessible to us. So that's a commonly used route to address problems that might be stemming from nerves that are inside the spine. And what a physician will typically do is inject some medication there. First we put the needle in, and then we inject what's called contrast, and you're probably familiar with it if you've ever had a CT scan. Contrast is typically given inter-vascularly. And it's medication that usually has iodine in it among other things. But it does show up as a dark line on X ray imaging. So it makes it easy to see are you in the right place. And what you see here, is that dark, it looks like a little bit of a Christmas tree picture in the bottom right there, that's a normal, a spread of medication that's in the epidural space from the Caudal approach. So that's how we would potentially do a Caudal epidural which would be appropriate if someone, if, from both from a diagnostic and a therapeutic perspective. So if we thought that part of the pelvic pain was due to some problem, in the epidural space, we could, from a diagnostic perspective, inject local anesthetic in that area and at low concentrations if that improved the pain then that might suggest that, that's part of the etiology of the patient's pain condition. So let's talk a little bit now about another part of the nervous system. So, the sympathetic nervous system, I think is probably even more valuable in patients with endometriosis, because, having seen lots of patients with endometriosis many times, after the endometriosis has resected and we can't find surgical evidence that it's there, the pain persists. And that happens for several reasons, but one of the reasons is that when people are subjected to a painful insult, such as endometriosis, there are a variety of things that happen in the central nervous system and the peripheral nervous system, whereby the nervous system is ramped up as we say. You'll also see the term windup. It's almost as if the central nervous system is sensitized and more prone to continue pain impulses, even after the offending problem has been fixed or has been removed. So this windup phenomenon that we talk about, it has both central manifestations and peripheral manifestations. So it means that it's occurring both at the level of the spinal cord, the brain, and also the peripheral nervous system. And one of the things that tends to happen, or can happen in folks that have suffered from pain for a fair amount of time, is that this part of the nervous system known as the sympathetic nervous system starts to conduct pain impulses. When ordinarily it does not. So if we step back for a minute and think about the parts of the nervous system. You've got the central nervous system, which is the brain and the spinal cord. That's the nerve center that's the part where most decisions are made and most decisions are started. And then you've got the peripheral nervous system, and then you've got the autonomic nervous system. So the autonomic nervous system is a lower level sort of evolutionarily speaking of nerves that is divided into parasympathetic and sympathetic. And I just mentioned here to give us some context so that we realize that the sympathetic nervous system usually does not conduct pain. However, in patients who have been suffering from pain for a long time, it can be important for continuing the pain even after the offending problem has resolved. So there's some examples here, of some of the functions that the autonomic nervous system controls. With the parasympathetic and the sympathetic nervous system, and the details as to where these nerves go is not important. I put the slide largely just to emphasize that the nerves go many different places and that they typically have antagonistic functions. So typically the parasympathetic nervous system, let's say, might up regulate some process, and the sympathetic nervous might serve to down regulate that same process. And whether they go up or they go down can differ based on which organ system, but ordinarily they act in harmony. But once patients have sympathetic mediated pain, that balance between the parasympathetic and the sympathetic nervous system is upset. And once that balance is upset sometimes the sympathetic nervous system, I sometimes use the word, is hijacked by pain, and ordinarily the sympathetic nervous system is supposed to just, largely for the most part be getting information from the brain and spinal cord out to the periphery. So just conveying information to our organs, so that our organs can operate effectively. But when the sympathetic nervous system is hijacked by pain, you suddenly get an influx of information. And sometimes you find pain signals that are traveling up the sympathetic nervous system instead of the usual routes that pain goes through, which would be the sacral nerves and the lumbar nerves. So that's an explanation as to what the sympathetic nervous system is, and I guess if I had to sum it up in just a couple of sentences I'd just remind everyone that it's not usually important to normal pain, but when pain becomes chronic the sympathetic nervous system can conduct pain in ways where it's really not supposed to when things are functioning normally. So with that background that sort of explains the next part of what we're gonna get into, which is what we can do to potentially modulate the sympathetic nervous system to try and improve a patient's experience of pain. So what we do is if we suspect that the sympathetic nervous system is involved in pain, and that comes largely from historical features, history and exam, but a lot of it is history based as opposed to physical exam based. And people who describe lots of burning components to their pain, pain that's very difficult to localize and most importantly pain that persists after what seems to be the appropriate, for instance, surgical treatments have already been done. When the pain persists after all those things that makes me think that we should at least consider that the sympathetic nervous system might be involved. And what makes the sympathetic nervous system somewhat difficult to treat, is that unlike normal peripheral nerves, for instance the nerves that fire when you hit your thumb with a hammer, or trip on a rock, those nerves tend to follow very discreet paths. And those nerve fibers are very organized into discreet nerves that can be found fairly easily, based on anatomical study and with ultrasound for instance. But sympathetic nerves are organized differently. So they tend not to be organized into discreet, nice little highways, they tend to be more like meshwork. So they might be spread out over several inches, or perhaps even a greater area. And they don't form these nice little highways that are easy to find and block. So to treat sympathetically mediated pain, from an interventional perspective we look for advantageous points. So there are certain parts in the body where sympathetic nerves do come together and they change from this meshwork into sort of more tightly defined grooves. And these are typically called ganglia, g-a-n-g-l-i-a, at least that's the plural form, and the singular would be ganglion, ending in n. And there are two specific areas that I think are especially applicable to certain patients with endometriosis pain especially chronic endometriosis pain. And those would be the ganglion impar block and the hypogastric plexus block. So, we'll start by talking a bit about the hypogastric plexus block. So the hypogastric plexus is an area of the sympathetic nervous system where some of these nerves that initially are, sort of spread out like spider webs start to come together before they enter the central nervous system, so now they're a bit more compact, a bit more easy to find. And the way we typically find them is we know from cadaveric studies that they tend to come together right around the L5 vertebral body, which is the lowest vertebral body in the lumbar spine. Just around the level of your belt. So that presents an opportunity, where if we have an X-ray machine we can take up either one or two needles depending on the technique, and advance these needles very slowly and carefully, kind of similarly to the way we would advance them in the case of an epidural using either X-ray or ultrasound guidance. But more commonly X-ray guidance. And if we can place these needles in the right spot, just anterior or just in the front of that L5 vertebral body that presents an opportunity to selectively block the sympathetic nerves, while usually leaving alone the somatic nerves, which are the normal pain relieving nerves. And once we can put some numbing medication, like for instance lidocaine on those nerves, that can be both diagnostic and therapeutic. So if that injection does improve part of the patient's pain, that suggests that, that part of the pain is being invaded by the sympathetic nervous system and that might explain why someone's pain persisted even after, let's say appropriate surgical treatment. This procedure is typically done as an outpatient. It doesn't take very long to do. The actual time in the procedure room, usually around five minutes or so, maybe ten minutes at the most. But like most other things in medicine, there's a lot of time like either in, doing safety type things, double checking the medications, double checking the patient, making sure we've done our due diligence to protect, obviously the patients. But the actually time of doing the procedure is usually pretty quick. Five minutes or maybe ten minutes at the most. And it has the potential to have both, diagnostic implications but also therapeutic implications. Because it's been postulated but clearly not prove, but hypothesized by many experts in the field that when you interrupt this cycle of pain information coming into the central nervous system the benefits may persist even after local anesthetic has worn off. So one of the things that facilitates sensitization or windup is the fact that the pain impulse continues. It's almost like what we call a positive feedback loop. So most things in medicine, and the way our body's designed, are, go along the lines of negative feedback. So if one impulse gets higher the body tends to tune most of those impulses out. But sometimes, in certain people, we get what's called positive feedback, whereby if pain is there, the brain and spinal cord will actually amplify those pain signals, and make you more prone to perceive greater pain than perhaps was initially there. That's called positive feedback. And the thought is that if we can break that cycle, whereby nerves are firing and sensitizing the central nervous system that we can partially desensitize the central nervous system by doing injections like this. And, in patients who perceive benefit from it, not in everyone, but in certain people, the benefit can persist for weeks, months, or even years after the initial injection. Long after the local anesthetic medication has worn off. For most of these injections, like hypogastric plexus block even patients who get only partial benefit the first time, sometimes they'll get similar or additional benefit after a second or even a third injection. And some people will come back routinely for these things. It could be once a year, it could be once a quarter, it could be once every three years, things like that. But people will know, fairly, you know, right away if it's helping them or not. Usually within a few hours of the first injection. So that was, again, an explanation as to the theory of why we consider blocking the sympathetic nervous system and a specific example of one convenient and safe place to block the sympathetic nervous system which would be at the hypogastric plexus. So how do we decide between these two possible targets? Well the hypogastric plexus tends to innervate part of the pelvis, but probably from the top of the pelvis, from about the top of the pelvis probably down to the pudental area. So for pain, sort of deep seated pelvic pain, the hypogastric plexus block is a reasonable option for many. For people who have more vulvar pain, more clitoral pain, more rectal pain, those are sort of lower down targets, and for those patients we'll typically start with something called a ganglion impar block so impar was an anatomist who characterized this structure and it's named after him. But the principle is similar to the principle we discussed with the hypogastric plexus. So again, this is an area where the sympathetic nerves, which are ordinarily very diffuse like spiderwebs almost and not sort of bundled together for us, one area where these nerves tend to come together, in a ganglion and are amenable to someone placing a needle near it, and potentially blocking nerves that cover a large area, with one singular or perhaps two injections at a time. So for the ganglion impar I'll show you where that lives, on this slide. How does this work here?. It doesn't, but. So the laser pointer doesn't work but if you get that last slide back. It's actually at the last one, it's the slide with the, sorry it's the second slide actually. So what you'll see on that second slide, the one with the two X-rays left and right, was, one slide before this I think. Yeah that one. So, similar to the caudal based approach, again we're using fluoroscopy for guidance and whereas with the caudal epidural the needle's actually going inside of the spine, the ganglion impar lives just anterior, just to the front of the tailbone. And in this X-ray picture it would basically be at the bottom of that, if you imagine that's a clock face. It would be just about at 6 o'clock on that clock face on the left. So what we would do is we would, again, under X-ray guidance take a fairly small needle. And between the sacrum and the tail bone most people, I'd say about 90% of people have a little membrane there that actually is almost similar to the discs that you have in your spine, and we can put probably a 25 gauge needle. So smaller than the needle that you give blood with, if you ever gave blood. We can take that little tiny needle and advance it in between that little tiny gap between the sacrum and the tail bone, just about 6 o'clock on that image. Again, we would get a little bit of contrast so we could see that nice dark spread that we were in the right place. And then we could anesthetize the ganglion impar with a very small amount of local anesthetic. Probably somewhere around 3 and 6 ccs of let's for instance 1% lidocaine, but you could use any of several local anesthetics. And if you were to anesthetize those structures, you would know within maybe a couple of hours to a day if it were gonna help or not. And some patients will report partial improvement in for instance their chronic pelvic pain, or their vulvar pain or wherever their pain might be. And that can also provide downstream benefits the same way we described with the hypogastric plexus. Whereby once you break that cycle of pain information coming up these sympathetic nerves, you can sort of desensitize the central nervous system in certain patients. So that's basically a brief overview of some of the three most common procedures that I perform for patients with endometriosis pain, specifically. Certainly no one is better or worst than the other. And deciding which one is basically dependent on history of physical factors when we discuss it with patients, and largely it's the location of the pain. So if pain tends to be more distal down, closer to the vulvar area, we think more ganglion impar. If the pain feels more deeper in the pelvis, closer to the abdominal area, we might think of the hypogastric plexus block. And if we thought there were some problems stemming from inside either the sacral or the lumbar spine. For instance, based on MRI for instance, then we might consider an epidural injection. For both diagnostic and therapeutic purposes. So I'll leave things there. And I think we've got another talk right before questions. So I'll hang around if there's questions at our questions session. Thank you.