let's go ahead and get started. Thank you everybody for joining us today. Welcome to AAP Virtual Didactics. We just had a great lecture. I'm excited for this one. Again, for any of you that are just joining us, the schedule for these lectures are at that website, physiatry.org slash webinars, and recordings of all of these will be hosted on that website at least through the end of this year. So for those of you who are at institutions where not all of your colleagues are able to watch these live, and we also recognize that clinical schedules are starting to ramp up, so please feel free to pass that along to your colleagues. We recognize that more and more of these talks are being watched in a delayed fashion. Okay, so again we'll kind of jump through some of this since we already discussed most of it this morning. We do appreciate those of you who are on the front lines of this COVID-19 pandemic recognize that there are those who are affected more than the rest of us. We appreciate those of you who have been professionally or personally affected by this pandemic more than the rest of us. We're gonna keep everybody video and audio muted except for our lecturer. If you have any questions, again, my name is Sterling Herring. I'm a PGY3 at Vanderbilt, so if you click on your participants button, you should see my name up near the top somewhere. You double-click that, you can send me a message, and then at appropriate times at the end of the talk or if our lecturer pauses and asks for questions, I can kind of present those at that time. That said, there is kind of an anomaly on this particular one. I'm gonna be stepping off the call at some point during the middle, and my colleague Evan is going to be coming on as well. He's a PGY2 here at Vanderbilt. He's gonna be helping me out. I have a meeting that I need to join about halfway through this, so if you don't see me up there, look for Evan Berlin or just ask it on the general chat. Further questions, you can reach out to Candice there at AAP. Her email is there on the screen as well as her Twitter handles. Without further ado, we're excited to have Dr. Heidi Prather on the phone with us, or on the call with us here from WashU in St. Louis. Welcome, Dr. Prather. There we go. Can you hear me? Looks great. Thank you very much. Every Wash U resident was just holding their breath because they know I'm technologically challenged. We have had our share during this year, as you might imagine. All right. I will attempt to see if I can get this on. So I volunteered to talk about... Can you still see that? I put it on the slide. Yes. It looks great. Okay. Thank you. So I gave a couple options of what I could speak about today to help supplement some of your learning. And the one that was chosen by AP was this one. And I originally gave this talk with this particular title, Evidence-Based Diagnosis of SI Joint Pain Pathology, Differential History, Physical, and Special Tests. What I'd like you to think about pulling apart those words is about evidence-based diagnosis of SI joint pathology. There is really so little evidence on this particular topic, most of which is surrounding injection-based learning of diagnostic and therapeutic benefits, but really so little on the other. Is it really just the SI joint that we should be talking about? And what kind of pathology? Because most of the time, you know, imaging is quite normal. And is this really just a structural problem? Specific tests, we're going to talk about really how specific are they? So I've taken away that title because it's very confusing, correct? What do you mean by all this? And really what we'll talk about is the history and physical examination for people presenting with posterior pelvic girdle pain, what we know and what we think. And using the term posterior pelvic girdle pain is important because people come in with this commonly. And even if you're not planning to be a musculoskeletal physiatrist in your future, everyone's going to tell you about their back or buttock pain at some point, whether it's at a luncheon, a dinner party, at the park, something. And your patients with impairments and disabilities, if you're a head injury or a stroke doctor, they have this as well. So this is kind of this unifying theme that a lot of us have to deal with in our practice one way or another, whether it's large volume or not. And the posterior pelvis, when people come in with posterior pelvic girdle pain, that's really how we should think of it. And it's not just one joint. It's not just one muscle. Oftentimes, piriformis is thought of being the sole problem of a lot of posterior pelvic pain. Oftentimes, it's a conglomeration of things. And we have to think about what occurs above the pelvis and the lumbar spine region and obviously what hooks into the pelvis at the hip girdle. And there's a lot of mismatch and crossover problems there. So the objectives of this particular talk is to recognize overlapping distributions of pain. We're going to differentiate what a structural problem is and what a movement problem is because that's what I'm constantly thinking about in clinic when I'm seeing patients with these disorders. We're going to look at the review of all structures involved. We're going to outline comprehensive physical exam and that it needs to be beyond provocative tests. And we'll go into why that should be. And then discuss how these tests can help us exclude other diagnoses. And a lot of times, when we arrive at the diagnosis of SI joint pain or we arrive at the diagnosis of piriformis pain, we've excluded a lot of other things. And that becomes the inclusion diagnosis because other things have been excluded. So when people come in, they say my hip hurts or my back hurts. These are just pain drawings from patients coming into my clinic with those complaints. Obviously, it's kind of all over the map and people present with different pain distributions. And so why is all this so confusing to us? Well, it's probably more than this structural change because why is it confusing? Seeing is believing, right? See something on physical exam. If we see something on imaging, if a surgeon sees something at surgery, that's the thing we believe because that's the thing we can see. The question is, hence, maybe there's really not oftentimes true pathology because we've never seen, that's not really been seen on any structural mapping or when a surgeon does surgery and decides they're going to put a screw across the SI joint. Are they doing it because they see a specific change at the time? No, it's usually because the patient reported pain, we did an injection, and then somebody determined that was an unstable joint. So getting away from this term of pathology and thinking of it more of as a functional and biomechanical load and stressor and absorber is what the pelvis is from the trunk down and the bottom up, and that's kind of the crossroads. So is it really pathology structurally or is it really other things related to movement, fascial, shear force, torsional force, and that exchange of motion across the pelvic girdle that we need to think about? The objective measurements are the gold standard, right? We have an objective measurement, that's what we use as a gold standard, and there are very few available for this diagnosis. We don't have a gold standard to measure the dysfunction of the pelvic girdle. We don't have a standard method of measuring any small microstructural change that might be occurring, so we're kind of left to it being more, again, exclusion and understanding and taking a history and exam and putting it together. We also know that pain outcome studies can't meet all the criteria for best level, right? It would be very hard to do a randomized controlled study on the effective treatment of SI joint pain if we can't agree on what the diagnosis is or that we have a gold standard for including patients in a study such as that. So maybe we should really think about returning to the concept that was first proposed by the Interdisciplinary World Congress of Low Back Pain that first met in the early 90s in San Diego, and this was a group that was formed by Vert Mooney, who was a pioneer orthopedic surgeon who actually thought a lot about function, and he paired up with an anatomist by the name of Professor Andre Vlemming, and they started this congress in the 90s and attracted about 200 people that first year who had just an interest in pelvic girdle pain. And the concept that they brought up at that time is, again, there's a significant overlap in the distribution of symptoms between our spine, our SI joint, and hip disorders, and that motion at the pelvis affects motion at the lumbar spine. They don't occur in isolation. We also know pre-arthritic and arthritic hip disorders can present with low back pain and posterior pelvic pain. I'll go over some of that with you today. And that hip motion is intimately linked to low back pain. We'll review that as well. And again, does passive hip motion actually influence adaptive patterns across the trunk, and can this lead to dysfunction? That's been looked at in laboratory measures now, and not necessarily something that's rolled out to you and I as clinicians. And I'll give a little bit of an exam that I use that tries to get us to that point. So why is, again, why is this so confusing? Why is this so hard to sort out, the differential diagnosis of someone with posterior pelvic pain? Well, there's all these other things that are involved there, right? There's the joint itself. There's the hip joint that screws into the pelvic girdle and has influence over that, both muscular and bony changes can affect that. There's the lumbar spine above, you have disc pathology, you have foraminal stenosis, neuropathic pain, that all kind of can mirror some of these disorders of the pelvic girdle. And then there's the anterior pelvis. You know, the pelvis is a ring, posteriorly, anterior lateral with the hip, and then anteriorly in the anterior frontal and sagittal plane, influences of the cubic symphysis. If you have instability there, arthritis there, stiffness there, previous injury there, again, that's going to affect the whole ring, which ultimately can be a contributing component to folks with posterior pelvic pain. The other thing is movement here is a little complicated. This is, I love this diagram. The right leg is outstretched and it's in heel strike. So the green arrow there on the femur just below the greater troch is showing that force going upwards. And as the force goes upwards, we expect the ilium to rotate in a sagittal plane posteriorly. While that's rotating in a sagittal plane posteriorly, because the ligament structures between L5 and the sacrum and L5 and the ilium, we have an expectation that L5 should rotate to the right as well, if mechanics are in a neutral position. If mechanics are in a non-neutral position, we would expect a combination of side bending and rotation to happen to the same side. While that's happening, you're going to have increased tension and force load along the ischium and the sacrotuberous ligament down there at the bottom of the ischium there on the right side has this forward motion in a sagittal plane. So you'll have tautness across the sacrotuberous ligament and that fascial plane then applies that force and stressors across the SI joint onto the sacrum. And this is if everything's happening the way it's supposed to be. If you have a little stiffness at L5-S1, a degenerative disc or herniated disc, this may change. If you have a prearthritic hip disorder, you may not actually have symptoms, but let's say you have impingement in your hip or you're somebody with extra motion at your hip because you're extremely dysplastic or you have a retroverted hip and your orientation increases that force load posteriorly, this may all be changed. So it's such a complex motion model system. A lot of times, again, assessing this in our clinical form can be quite, quite difficult. We have to make a lot of assumptions. So in this talk today, it's not all about the joint. And when I talk about posterior pelvic pain, I really talk about it in the scenario of these different things. I think posterior pelvic pain in a pregnant population is very different than posterior pelvic pain in a non-pregnant population. Infection, tumor, and fracture, obviously very different. Inflammatory arthropathies, that's a separate group. They're different. They respond to treatment differently. Trauma is definitely a different group. People who have had hip or pelvic surgery, there's two studies in the last 15 years looking at spine surgeries and spine fusions in relationship to posterior pelvic girdle pain. Obviously, people with connective tissue disorders, particularly people with hypermobile states, that's a different population. But the vast majority of what we'll talk about today is really that idiopathic group, which is probably the vast majority of folks that we're seeing, which is they got buttock pain and we're not sure why. So pain can be related to adaptive patterns to regional injury and other disorders across the lumbar spine and pelvis and hip, as we've talked about, whether those are within the hip or outside the hip, pelvic floor, pubic symphysis, or the outside joint, and then anything along the lumbar spine itself. The differential diagnosis, again, when I'm thinking about it, I'm trying to, if I'm seeing somebody with posterior pelvic girdle pain, those are all the things I'm kind of keeping in mind that I need to narrow my diagnosis down from, and sometimes I'm having to exclude some of those to narrow it even further. So things we know about lumbar pelvic pain, we know what lumbar radiculopathy, the distribution of pain, what does it look like? Well, that's the original LeSue sign from the 18th century drawing, sciatica, vert muni, again, the orthopoda we talked about previously. This is the original diagrams from his first study that showed if I put distendo-facet joint, this is the distribution of pain the person will exhibit, and then the Fortin sign, which is a collaboration of pain models and people who responded SI joint injections, this was their common distribution of pain, and we understand and we're comfortable with some of the structural things that go along, particularly with facet orientation or radicular type pain. We're comfortable with the associations to some of the anatomical models that go with that. But there's also some other things with similar distributions of pain. The Kahn study in 2004 showed that 47% of people who had hip pain had pain below their knee. And from the Lesher study from Pain Medicine, this is the drawing here on the illustration on the slide here is from that paper where they took patients, they were all osteoarthritic patients or hip osteoarthritic patients, and they had an injection. And if they reported 90% of their pain was relieved, they then took that pain diagram and overlapped them, and this is what that overlap looked like. So pretty high criteria that most of their pain went away with an inter-articular injection, and yes, some of them had foot pain, which you can see there. So we have to be respectful that people present with pain in lots of distributions. Then there's also the concern of, you know, we're always looking for the one thing it is, but oftentimes people come to you and it's not just one thing, and there can be an overlap in symptoms and different areas that are contributing to the patient's overall clinical symptom complex. This is a study from Dr. Cimbrano and Dr. Polley up in Minnesota, and this was done at a VA. So everybody who came in having their spine surgeons, anybody who came in and had back pain, they went through an injection of their spine, of the source they thought it might be from, of their SI joint and of their hip. And you can see the different percentages are in the different rings of the people that got benefits from each of those injections and that there was obviously a considerable crossover with, in fact, you know, up to 2% of people were actually having relief with all three. So injections obviously are helpful, but this kind of gives us pause that oftentimes people do have considerable overlapping symptomatology. So I've been very interested in that, and some of my research work has been geared towards that, looking at this interplay between the lumbopelvis and the hip, and we know it's a conundrum for our patients because they come in and say, I've got hip pain, and I saw this doctor, that doctor, and everybody specialized in one thing and pointed the finger at the other provider who might take care of them, but it's also a conundrum for those of us who are healthcare providers trying to differentiate it. So I would suggest we should look hard at what we get from our history, what we might get from the physical exam, and what diagnostic tests might help us, you know, really get a clue on how to assess this patient, get a clear diagnosis, and work towards a treatment plan. This is from Mark Laslett. He's the author of one of the papers you'll see often that you quote, looking at the importance of using multiple tests to look at people with SI pain, and he's written quite a bit about it, and I loved this descriptive about the use of words, because our use of words sometimes we muddle what we know because we don't use our words distinctly. And just an excerpt from that. The perspective proposes that this joint is malfunctioning in some manner, and the word dysfunction is commonly used to encapsulate the complexity and aberrations believed to occur around the SI joint. So, unfortunately, the terms SI joint dysfunction and SI pain are commonly used interchangeably as though they have the same meaning, and that's really the heart of we have to, you know, people can have dysfunction and it be asymptomatic in one part, but may lend itself to appearing in another body part, and that's why we as physiatrists really have a heads up against, as compared to other specialties, because we have that understanding. But I think it is really important to define, am I treating something that's dysfunctional, or am I just trying to zap pain, and have I really identified that the SI joint interticularly really is the pain problem? So, again, going back to why the conundrum, some of it's just our word usage. So what's unique about people's history when they come to see you? So people that tell you this started, I have it chronically, and it started during pregnancy, that's a group that you might hear from. Also, if they've had a history of surgery in their hip, spine, or pelvis, any occult trauma they may not have originally told you about. And then the idiopathic group especially ask about activities that require repetitive pelvic shear and torsional forces, like the soccer athlete here. Those people are at great risk for developing this, or have had that in their history. This is one of those studies I was talking about, I looked at folks, this is from Larry Tu back in 2004, looked at a descriptive cohorts series of folks, 54 of the patients who had had a positive response to a diagnostic and therapeutic injection, 44% of them had a history of trauma, 21% had a cumulative injury, and 35% were grouped in that idiopathic group. So again, if we ask the questions carefully, we may get away from this kind of a black box as to why this is happening to a person, so taking that history is pretty important. And then what symptoms they might have, oftentimes people with posterior pelvic girdle pains initially present with unilateral pain, but obviously it can become bilateral, pelvis is a ring, so the sheer force transition is affected throughout the ring. Provocative activities, including sitting, transitional activities, and I always ask about if you increase the pace at which you walk, does that change your symptom, and the reason for that is the closer you get to a single leg stance activity, usually the people become provocative. So even if you don't have a runner in your clinic, you can even ask them to try that in the office if that's symptom provocative, it's a good hint. Transitional activities, what I mean by that is getting up and down, getting out of a car, transitioning in and out of bed, that's oftentimes this group of patients will note that their symptoms increase. Again, localization, we talked about posterior pelvis, thigh, groin, and lower extremity, and then oftentimes they'll assess, they will admit to having clicking or be alarmed by having popping or clicking in the posterior pelvis, and if they don't offer it, I actually ask that question, because for some people that's very anxiety ridden to them, that oh my gosh, something is making noise in my body, I must be dying kind of thing, so I'm usually pretty careful to ask, do you feel a pop or a click with this, and then that can start with that dialogue of trying to go down the road of that won't cause harm, but it gives me a hint as to your diagnosis. So going back to understanding the biomechanics of this, I think the most important thing I hope people get this conceptual know of is the importance of form and force closure across the pelvic girdle, and we'll talk specifically here about the SI joint. So this is from Andrei Vleming's original works in the early 90s, we looked at form closure for the SI joint is really where the two joints fit well together from a bony cartilaginous structure, so that's the ilial side and the sacral side fitting together well as two pieces in a puzzle would fit tightly together. Force closure then is the comprehensive forces that are required to promote joint stability, so that's all your muscle and ligamentous and the capsule forces that go across the joint that provide stability for the joint. And this was from their first two papers in early 1990. About five years later they went on and added these last two things they said were equally important for joint stability, which included motor control, which is coordination of muscle activation, and of course they were ahead of their time because the lumbar spine world about 10 years later went to this as being one of the most important things for lumbar spinal stability is neuromotor control, which I know you're reading about now when you're looking at biomechanic literature and such for low back pain, so this group was a little ahead of their time. And then understanding emotion awareness and that the way we process pain has a lot to do with how we exert motor control and if we have poor motor control we're going to have poor force closure and therefore leads to less joint stability. So understanding this is a real important factor. So there's ligaments of the posterior pelvis and I divide them into intrinsic and extrinsic, so the anterosacral ligament, the interosseous ligament, and the posterior sacroiliac ligament. The interosseous ligament is the strongest one, one of the strongest ligaments in our body, very short and stiff, and it provides a lot of stability across the joint. Let's see if my lights are on. Here we go. The sacrotuberous ligament is an important ligament to understand. It's extra articular to the joint itself, but it's really important in force and load transmission from the lower extremity up through the trunk and has direct connections to the back of the sacrum and therefore tautness because the sacrum head does have a little bit of motion in it with normal activities, it has implications onto that. There's tons of muscles involved in people who present with posterior pelvic girdle pain. I've just listed some of them here. We need to think about things in chains and links and how they cross the body, cross the pelvis, and they can be important in stabilizing. And picking these out based on functional testing and examination of motion can be quite helpful in this patient group. And just don't forget the pelvic floor and the diaphragm are both involved in this inherently as part of the disorder. So we also know that muscles have to work in balance, they don't work in isolation. And so we know the iliopsoas is one of those muscles that's always a kind of a conundrum because people can have pain in it, but it has this indirect effect on motion through the ilium itself based on your hip motion and your spine motion. So it's that one thing that crosses the front of the joint, but it's affected by motion at two other joints. And oftentimes, this can be a painful contributor to folks with posterior pelvic girdle pain and the whole question you'll have is this a muscle that's short and not working well or is it really a muscle that's actually long and what I call on, meaning has increased resting tone because it never fully relaxes. That's very hard to pick out and it takes time to get confidence in what skill set you have with doing that because there's no, again, objective measure of it, but just keep that in consideration and people that you're getting stuck with, take a careful look at how that muscle's working strength and length wise. And then the thing we talk about often is in posterior pelvic girdle pain is the piriformis and really there's other deep lateral rotators that are oftentimes involved, but the unique component of the piriformis is it's the only deep lateral rotator that originates from the anterior side of the sacrum and for that reason has sheer force along the sacrum and ilium as a result. The other muscle that's contiguous about 42% of the time with the piriformis on cadaver studies is the operator internus and that's a pelvic floor muscle that also is a primary hip mover. Oftentimes this muscle can be involved as well. This again is from Bleming's work. This is looking at fascia and we know from our early studies from Pandavi and White that fascia is the thing that helps us transmit force in the lumbar spine from anterior to posterior and when our fascia does not have good integrity we have less stability. So Dr. Bleming took that work and then dissected the cadaver below L5 and showed that the posterior layer of the thoracolumbar fascia actually crosses at L5 and it communicates down the opposite side hamstring up through latissimus dorsi through the arm. So this is really where you show the leg bone is connected to the arm bone and that crossing is again around the lumbar spine posterior pelvis. The other things obviously to take into effect with these folks, we talked about motor control being important and how if people are in an anxious state or are in a troubled state, how their endocrine system gets worked up, their nervous system gets worked up, and those are the people that can have that pain that doesn't seem to come into any significant distribution. So people with chronic pain and people who have increased parasympathetic and sympathetic nervous system activity with cortisol levels that are higher and angry often will have pain that again doesn't seem to fit one specific diagnosis. Folks that walk around with undiagnosed posterior pelvic girdle pain can fall into this group not uncommonly. And so making sure that we're not only focusing on what do they need from a posterior pelvic girdle standpoint, but what do they need from managing their chronic pain syndrome and understanding that those can be distinct things is very important in this patient population. So physical exam, basics, right, we know we have to do muscle stretch reflexes, manual muscle strength testing sensor exam, we look at bony landmarks, or at least I do, and see standing supine and prone because that really helps me visualize what the person looks like in front of me and then extrapolate that to motion. The single leg stance and squat really helps me determine lots of things with one little test like do they have strength approximately, do they have a good motor control across their pelvis, if their pelvis is immediately dropping, I already know we've got issues there. And then quality of lumbar range of motion, not just can they get there, but do they move only through their pelvis and they hyperextend their knees to go into forward flexion, or do they naturally flex through the lumbar spine and the rhythm of their pelvis kicks in when we think it should somewhere after about 40 to 50 degrees of lumbar flexion, that's when our pelvis should kick in into flexion or anterior rotation and sagittal plane. And is that happening? I always like trying to get more than one thing out of one test because none of us have enough time, or not the time we want with patients, but those are some of the obvious basic things we need to do. And then what makes a difference for me is looking how they walk, do they have neural tension signs or not, do they have a directional preference to their pain, so if they go into lumbar flexion they feel worse but feel better with extension, I think about that posterior pelvic girdle pain person much differently than not. What's their hip range of motion? So folks, we'll talk a little bit about that. Do they have hip provocative tests? That can be very helpful because some of those will present, their hip provocation tests will provoke pain both in the posterior pelvis and groin or lateral hip. What does that mean? I don't know that we know, but I note it. Do straight leg raise, it's like the poor man's view of motor control in a very short time in your clinic, so I think that's helpful. And then I'll show you lumbopelvic motion, I look at pain of PSIS and sacral sulci, there's a study written by Paul Dreyfus that showed if they have pain there, about 60% of the time those folks will have relief with an interarticular injection. Not perfect, but again, helpful. And then looking at ASI joint provocative tests. So we know directional preference for low back pain has become much more well established in the past, even just 10 years, and this study by Long showed that of the 230 patients that came in with low back pain, they could figure out a directional preference in about 74% of them, and that means they had pain that got worse with flexion or extension or side bending rotation, and that of the other group, the 26%, they couldn't classify into a directional preference, and the authors at that time said, well they must have behavioral problems or instability. Well I wonder, I question, maybe it's not the spine, this is maybe a posterior pelvic girdle group. So again, looking at if their pain is provoked or relieved in lumbar spine motion, if it's not, I start thinking it may not be a primary spine disorder that I'm looking at, I need to look at hip and pelvis. Again, gait, do they have any naotalgic gait, lumbar shift, do they circumduct, do they hip hike, those are things that you can help look then at specific muscle groups once you assess gait. Neural tension sign obviously is very helpful to figure out if they have potentially a neuropathic component to their pain. Passive hip range of motion. I consistently do these three on anybody presenting with back, hip, or pelvic pain, looking at hip flexion, look at hip flexion, or hip internal rotation with the hip flexed at 90 degrees, and external rotation at the same. We've done some reliability testing of that with multiple disciplines of multiple levels of training and experience and find that we actually are pretty reliable at measuring those things. I do measure those and then also look for pain at end range with them. Again, note the location of where that pain is because oftentimes end range pain may actually present in the posterior pelvis and not necessarily in the groin or lateral hip, so being careful to ask about where their pain is is important. Other physical exam tests include the hip provocative tests, and again, we've looked at interrater agreement between these and found that we had a 95% interrater agreement. Whether they were a medical student or somebody who'd been doing it for 20 years, we seem to agree with these, so they seem to be good ones to use. Log roll, hip impingement test, or FADER. Hip impingement, just know the hip is only flexed at 90 degrees, versus FADER is end range of hip flexion, which maybe is variable based on the patient. Faber-Patrick's test, and then a resistive straight leg raise. Other things we'll look at, I'll use the active straight leg raise. I really like this test. It's reliable in assessing patients with pelvic girdle. There's whole bodies of literature on this. If you're interested in it, I would really look at Peter O'Sullivan's work out of Australia. He's separated work through the active straight leg raise on multiple patient groups, and it's very comprehensive, and again, in a series of studies they're looking at pelvic girdle patients versus asymptomatics, and they could see these differences in movement patterns, respiration, and pelvic floor activity in patients who had a positive test. So here's an active straight leg raise. Again, patient's supine, and the patient lifts their leg. It's supposed to be 29 centimeters, which is probably a little high, and they note whether they have pain or the leg feels heavier on one side versus the other. The examiner then compresses the ileum, and if the patient's pain or assessment of heaviness of the leg resolves, we call that a positive test on that side, and it's really kind of giving you an illusion to poor neuromotor control. This is when we were talking about looking at stuff that's been done in the lab. This is a test that I use commonly in clinic that we are hopefully going to look at if the translation from the lab to the clinic is going to be possible. I'm working on that with some residents at Wash U on this now, and again, I credit this to my research mentor, Linda Van Dylen, who's a PT PhD who's been NIH funded for over 20 years in back pain, and she's done a lot with looking at lumbopelvic motion. So the examiner on the left, he's got his hand monitoring the patient's alpha and sacrum region, and then he's going to passively move the patient into internal rotation and external rotation of the hip, and then I'll have her actively do that, and if his left hand there, he feels the sacrum rise or come towards us in rotation within the first 50 degrees of available overarching motion, we call that early lumbopelvic motion. Now she studied this in the lab, and I've butchered it and taken it to clinic because I find it very helpful, but this can give you again kind of the poor man's view of are two segments working together or are they kind of something stiff and every time I move their hip L5 is moving, we know that force is being transmitted across the posterior pelvis and it becomes an important part of my assessment. Other things we know to do, the straight leg raise, the Faber's maneuver, the piriformis, and even single leg squats, and just be careful, but what are these things provoking? Are they provoking just interarticular SI pain or hip pain or are they provoking a multitude of things? So we know from a group of studies looking at pain provocation tests on physical exam for SI pain, the Dreyfus study in 96, I think it was the first one to come out looking at this, we take experts who show great intraobserver reliability in these tests, there was actually poor correlation of what they thought they saw on a single provocative test and an SI joint injection response. So that led into these other studies looking at it takes about five provocative tests or three out of five provocative tests to be positive that are intended to be provocative of SI pain that might best correlate with a positive response to an injection. And so maybe some of those that are doing these right now, you'll see you're attending, so we've got to have three tests, and they say we have to have three tests, it's based on these studies, but it's also based on the fact that many insurance companies have adopted the fact that the only thing that tells you they have SI pain is if you have three tests positive, which is a little crazy, but that is the state of where we are, so if you see that happening, that's why. The Arab study there in 2008 showed palpation provocative test clusters showed moderate to good interrelator reliability, and I think that's important, I think the palpation piece is very important to describe where the patient's pain is, where you can actually provoke it. But again, insurance companies aren't real interested in that, they're only interested in the three provocative tests, so just understand that. Again, the last study, probably the one most quoted, look at 48 patients with low back pain, and it correlated individual tests. So the individuals, one test was positive, the sensitivity was in the 0.6 to 0.88 range, and specificity, you can see there, but the prevalence of one positive test was somewhere between 29 and 50%. But if they had three or greater tests positive, the sensitivity went way up to 93 sensitivity and 78% specificity. And again, the ones they used in their study was distraction, compression, thigh thrust, gainsense, and sacral thrust. The problem is the studies I showed you on the previous slide used different provocative tests. So again, we're not studying a uniform thing, or we're getting probably different outcomes. So again, here's some other, I've just listed them for you, you think you'll have access to these slides, just as other places to read, where again, these multi-testing things are pretty important, but again, people are using different tests to measure it. This was from the last study, and Van der Rohe study is looking at the validity of multiple positive provocative tests, and I'm just living in here, and you could see how that increases the more tests that are positive. So our comparison conclusion then is what we were talking about, greater than three positive provocative tests have 91% sensitivity and 78% specificity, and that specificity increases to 87% in patients whose symptoms cannot be centralized. Again, so that goes back to, is there a directional preference, and can we get their pain from distal to centrally? Probably that's gonna be a much more specific outlier. And then in patients with chronic pain and no centralization of pain, they have the probability of SI joint pain is somewhere in 77%, so a 10% difference. Again, this is really, it's picking apart hairs to some degree. So it's unknown if a provocation test can reliably identify extra-articular sources of SI, not intra-extra. So this is the table I write it out, and the thing here, I'm looking at these different tests for different body parts, and the lumbar spine, I'm looking at my neural tension, and my stork for extension bias pain, and then do they have a directional preference? In the piriformis, again, if they have pain with lumbar flexion and hip flexion, the six sign of pain, resisted hip extralotation, and obviously on that one, you use palpation a lot, they'll use neural tension sign a lot, but just pain in their piriformis, those are probably the things that can be helpful. And then SI joint, we have all these different provocative tests that are listed there, but if you look at it, there's a little bit of overlap here somewhat with hip provocative tests as well, particularly the Faber-Patrick's, where their hip pain is, compression along across the sacrum or thigh thrust, again, your thigh thrusting through the hip. So again, keep in mind, what are you really provoking when you're doing some of these things? Diagnostic testing, so we know for SI pain, this is not so helpful a lot of times, but it's important to exclude other things. So we know x-rays do not indicate a source of pain, best view is actually the 30 degree angle AP to actually get through the SI joint. It is important though, to make sure you are identifying somebody who is not idiopathic, but may have true sacroiliitis, which you would see on plain x-ray performance, in that person's course, you would expect to be very different than somebody who has idiopathic pain. And again, patients with sacroiliitis, you would expect them to have highland cartilage changes or fibrocartilage changes, so you would see those changes on the sacral side first, theoretically. So CAT scans, they can show you earlier joint narrowing, we know that's negative in 42% of patients with symptomatic SI joints. Bone scans, again, they can help exclude fracture, tumor, and infection that you weren't previously seeing. MRIs, same kind of thing, and this is an MRI, it's a little blurry on the screen there, but this is a runner who was treated for SI pain for about a year and a half, and she had a stress reaction in her ilium and her sacrum, so oops, we don't want to miss that. And then Doppler imaging, and this has never come to fruition, but it was a really cool thing, it was being done in Europe in the mid-2000s, it was Jeff Erickson, he was a physiatrist at VCU, actually went there and completed the model here in the United States, but it never went further. But what this was, was Doppler imaging where you measured stiffness across the joints, and they showed reliability, it was just really hard to reproduce. I'm sorry, the x-ray, this is a case study we presented, or we published in 2010, this is somebody who was treated for SI pain and they needed a hip replacement, so just remember that, can walk into your office. This is, again, from Dr. Erickson's lab, and this is actually my pelvis, and you can see on your right side of the screen, it looks like squiggly butterfly ink spots, but this is the Doppler imaging vibration across my right SI joint, and on the left side is my left SI joint, and there's an asymmetry there. And the studies that showed validation of this in Europe showed that the amount of vibration wasn't different if you had SI pain or not, it's that people who had SI pain tended to be asymmetric. And that so fits with every other thing model-wise you think about in these patients. So really cool thing, never has really come to fruition clinically, but makes sense, and I wish we had access to something like this because it would definitely help. I objectify true quote dysfunction, that seems to be a nemenis for us to describe. So what are things we can inject and confirm the diagnosis? Again, history and single physical exam tests for SI joint pain have not been validated via intraticular injection. We've got to use multiple tests and then doing an SI joint injection can be very helpful in diagnosing this disorder if it's intraticular pain. We know pain provocation tests can be correlated with these. Again, the last lab patient showed that. And again, a lot of times why that's the history behind, from an insurance perspective right now, you need those tests positive before you're granted to be allowed to do that. So also diagnosing intraticular pain, diagnostic injections for the hip can also help you exclude the hip as the primary problem. And the Prater study there in 2007 looked at injections, if you're differentiating a hip from a spine problem, the sensitivity and specificity were quite high. And sometimes I will use this, but I'm really stuck and I'm not sure. We usually use about four cc's or total volume, maybe half Lido, half Ropivacaine. And then do our provocative tests afterwards and have the patient do a pain diary. And that can help us with a diagnosis. So again, how do we make the diagnosis of SI joint pain? So the diagnostic criteria should be no neurological deficit, no neural tension sign, no objective testing indicating some other cause or medical cause, no evidence that we think this is from the lumbar spine and potentially 75% relief with an intraticular injection. This is a conglomeration of these studies. They're somewhere between level two and level four studies I've set here. So thank you for listening and watching. I'm happy to do any questions. And I have to figure out how to do it, hang on. Hey, Dr. Gray, thank you very much for that talk. You on the SI joint pain and back pain in general. So if anyone does have any questions, feel free to ask in the chat or look up me specifically. My name's Evan Glenn. I know we have one question here on the topic of benign, but distressing like pops or clicks. What do you normally say to the patient to explain to them what's going on and how do you provide reassurance with that? Yeah, that's a great question. So some of the original studies looking at SI pain, look at Paul Dreyfus was one of the leaders in our field that looked at a lot of this data. And he's the one that originally talked about the percentage of people that had clicking and popping with SI pain. So number one is I ask him, where is it clicking and popping? So if it's clicking or popping posteriorly versus in the hip, because those are two different beasts. Reassure them that that's a noise. It just means we need to work on stabilization. It does not mean you're destroying your cartilage. It does not mean that this is a horrific problem, just like with other things. And if they're feeling the pop anteriorly, whether that's lateral or anterior groin, then I'll kind of go back through looking at length and strength of the iliopsoas, is it painful? Can I actually palpate the pop and kind of go through the clicking hip conversation? In that group in particular, whether intro or extra articular, I'll also quote some of our work we did before in soccer athletes, where we looked at asymptomatic, it was all girls. So there was a gender discrimination here, but it was all girls and they were high level soccer athletes. Division one from a club in town where 98% of the kids that were on the teams that we were studying went on and played division one. And then we had a women's professional team that were in the cohort. So we took that whole cohort and they were asymptomatic and we examined their hips. 30% of them were popping. None of them had any of the signs associated with interarticular problems on the rest of the test. So I usually quote that as well, meaning I've studied this, you click and pop, we've never seen an association that click and pop means you're gonna develop a disorder. So I think reassurance is a big thing, but being concerned about where it is can really help. The other thing is that when they tell you they have this clicking and popping, and you remember, did I do the active straight leg raise or not? Go back and do the active straight leg raise. A good portion of those people you'll see will have clicking or if they complain of clicking or popping, a good portion of them will have a positive active straight leg raise. And the next thing I usually recommend to that group is an SI belt. And it's amazing how either the clicking or popping diminishes or gets somewhat better. And then they're starting to already, and that's in the room and they haven't left your office yet. And they're already buying into that. You've got them on a course that seems to be good for them. Okay, sounds good. Thank you very much. I know another question that someone had was that a recent study published in Pain Medicine by Dr. Kennedy here at Vanderbilt showed that none of the provocative maneuvers, either single or in combination, did not show any good sensitivity or specificity for diagnosis of SI joint pathology. And they just wanted to know if you had any comments on that. Yes, love the paper. I love the paper. It feeds right into what I just talked about. Yeah, it's a crazy notion that we would define the diagnosis of something by somebody's subjective response back to us about their pain level, because that's really what it is. I mean, that's crazy, right? And the reason why we should be so careful of that is not just what we're doing with injections, but we've got people fusing the SI joint now pretty commonly, more commonly than ever. And so I think some people really will benefit from that, particularly post-traumatic people, particularly people with connective tissue disorders that have, like, they don't have any force closure going on back there. So maybe that's the group that, but that's not what the indication is for those things. The indication is pain relief after an injection. So it's a very circuitous conversation, I would say, about that. And yeah, I'm thrilled he published this. Yeah, I think it's more cause to pause, and shouldn't we have better evidence from our history and our clinical exam than three tests to be injecting people? You know, a Faber test provokes posterior pelvic pain. What does that mean? And there's some people, I think, that are online with us now from our group that helped look at too many X-rays of folks that we brought in for hip injections, or I'm sorry, for SI joint injections, and then we went backwards and looked at their hip X-rays. And so we didn't report on how well they did with the SI joint injection. You just got to have faith in us. There were six physiatrists that said, nothing else is working. I'm taking this person to the floral suite, and we're doing an SI joint injection because they meet the criteria for that. This is in people under the age of 40, because vast majority were women. So again, can't extrapolate to both genders. But I thought, I asked everybody to go off on a wondrous adventure into this study, thinking, oh, we're going to find FAI, we're going to find a bunch of dysplastics, that's going to go into this, exactly what Dr. Kennedy is writing here, like maybe we should rethink what our provocative tests are and we're going to find them. Well, we didn't find that. We found that 42% of them had acetabular retroversion. Now, I'm not saying acetabular retroversion is causing SI pain, no. I'm not even saying acetabular retroversion is causing posterior pelvic pain. But in normal populations, only 15% of people have acetabular retroversion. Something's going on, right? And that's all the paper is. So there's some other people still on here now that we're looking at. We're trying to get to 1,000 reads on an X-ray so we can do gender comparisons in the group over 40, and a third of them have hip replacements or have severe hip OA or moderate to severe hip OA, and the rest actually do fall into a category for pre-arthritic hip structural change. So I applaud Dr. Kennedy. He got turned down to put it actually in another publication that I wish it would have been in, and I'm glad he went and published it because I think it really starts to open up our eyes about we need to have better means of classifying things in patients with posterior pelvic reloping. Okay, awesome. Thank you very much for that. So I'm assuming that you do most of your SI joint injections under fluoroscopy. Do you have any hope or, I guess, what are your thoughts on ultrasound-guided SI joint injections in the future? Yeah, I think, absolutely. I think we need to think about with anything we do, particularly with fluoro versus ultrasound, is like which patients do the best with it? And in the beginning, literature has to start off with, oh, it works, right? It works, this works. But it doesn't work in certain populations. So size, what their disorder is, previous surgery. My biggest thing about ultrasound in anything is can I really adequately see that I'm in a vascular structure that's not? And I think that's your biggest worry because the last thing you want to do is inject a steroid into that. So that being said, a pregnant population is the one, number one, that we should study that in because they can't have fluoroscopy. And they do need short-term intervention. And depending on their size and adequate visualization, it could be a home run for that population. So to me, where we need to be going is who does it work best in? And then make sure those people can get access to that versus we're going to do it all this way or all that way because we know that never works, right? There's always some area of gray in that. Okay, awesome. I really appreciate that. So if there's no further questions, I will go to the next slide. And thank you again, Dr. Prather. This was a very good talk. And we really much appreciate you taking time from your day giving us this talk. If you have any questions, anyone in the crowd have any further questions, there is Dr. Prather's email and then also Sterling's and AAP's Twitter handles. I wanted to ask them any questions. And this lecture is being recorded and will be available on the website probably tomorrow. And I was told that I was going to get yelled at if I didn't tell you that Dr. Sullivan says hi and gives his blessings to you. Tell him hi back. Okay, I will. Thanks for having me. Thank you very much. Yeah, thanks for having me. Good luck to everybody working hard and this is a really weird time and you'll never ever forget it. Agreed. All right, have a good one, everyone.

SI Joint Pain Pathology

Dr. Heidi Prather

biomechanics

comprehensive history

physical examination

provocative tests

diagnostic imaging

research

AAP website