All right, let's go ahead and get started. I want to welcome everybody to the AAP virtual didactics for today. We're excited for today's lectures. First, as always, we want to recognize and appreciate those who have been affected most by the COVID-19 pandemic. Recognize that not all of us have been affected equally, so for those of you who have been personally or professionally more impacted, we appreciate your efforts and certainly support you. If there's anything we can do further to support you, please let us know. As always, we're going to start with kind of some front matter here. The goals of this program are to augment didactic curricula that are currently ongoing at your home institutions, to offload overstretched faculty due to some of the logistical challenges posed by COVID-19, provide additional learning opportunities for off-schedule residents. Again, with some of the difficulties in terms of scheduling, we recognize that that residence schedules have also been affected, so we wanted to try to facilitate further learning opportunities there. Provide more digital learning resources and to support physiatrists in general during the COVID-19 pandemic. General housekeeping things. As always, we're going to keep everybody video and audio muted. Purposes of that are to maintain bandwidth and also minimize distractions. If you have any questions, if you'll click on participants, you should find my name up near the top. My name is Sterling Herring. I'm a PGY-3 at Vanderbilt, and so if you up near the top of that list, you should see Sterling Herring. You can double click that, send me a message, and then at appropriate times, I will ask them of our lecturer. If you have any general questions, concerns, suggestions, anything like that, there's the email of Candice there at AAP, or you can find us on Twitter. So without further ado, we're excited for today's lecture. Dr. Jonathan Kirshner is the Fellowship Director for Spine and Sports Medicine at the Hospital for Special Surgery in New York. Welcome, Dr. Kirshner. Thank you for joining us. Thanks so much for having me. I hope you can hear me okay. I'm going to share my screen. Can everyone hear me and see me, or see the screen okay? Yes, looks great. Okay, great. So thanks so much for having me. And again, my heart goes out to everyone and anyone affected by COVID. I'm located here in New York City where we certainly have been dealing with it. So I hope everyone is well and safe. My goal today is to discuss how I approach a patient with low back pain, and I've geared this to be at sort of a resident level, but hopefully the attendings in the audience will learn a pearl or two here or there. I don't have any disclosures relevant to this talk. So as far as the scope of the problem, regardless of your specialty, if you're a physiatrist, you're gonna end up seeing a patient with low back pain in your office. In 2012, there were over 50 million physician visits for low back pain, and you can see the numbers steadily rising. In 2012, 29% of people over the age of 18 experienced some form of back pain. 36% of these patients also had pain radiating to their leg. So when we talk about low back pain and lumbar disorders, I'm gonna lump radicular pain into that as well. Females experienced more back pain than males did, and the highest rates for back and neck pain were actually in the 45 to 64-year-old age group. So in our more senior individuals, there's actually less back pain. So this certainly affects the working population, which is why it's so important and has not only medical implications, but economic as well. So why is it important to make the right diagnosis? Well, certainly patients wanna get better quickly. We wanna help them get better quickly. You really wanna optimize their treatment plan. A lot of these lumbar disorders are going to improve on their own, but it's important to sort of risk stratify and determine what is gonna get better conservatively, what may need specialist referral, which patients have red flags that may suggest a more severe or urgent matter. It's also important to better manage expectations. A lot of our patients are well-read. They've done homework. They may come in having a certain diagnosis in mind or a certain expectation regarding return to work or sport. So depending on what their diagnosis is, certainly we can help them gauge those expectations. So that's one of the big pearls that I stress with my residents and fellows. You really wanna ascertain what those expectations are in the beginning and don't make assumptions. A lot of patients come in with fear and there's a lot of fear avoidance behaviors that can get in the way of someone getting better from a lumbar issue. So you wanna be able to figure out what their expectations are and try to manage those as best as you can. Also, unfortunately, we're limited nowadays by the amount of physical therapy a patient can have. So you don't want them to use up all their physical therapy visits for the year and realize, oh, shucks, we're treating the wrong diagnosis. Now that we have a better diagnosis and they need more therapy, their insurance isn't gonna allow it. It can be expensive. So when it comes to the diagnosis, you wanna think, is this a back problem or is it a back and a limb problem? So that could be the buttock or the leg. Is it a musculoskeletal problem at all or could it be referred from a medical illness like an abdominal aneurysm, a kidney stone, some more systemic involvement like a rheumatologic disease or different types of chronic pain symptoms like fibromyalgia? Is it a mechanical problem? Mechanical low back pain is not my favorite diagnosis because if it's a musculoskeletal or orthopedic type problem, it should be mechanical. When you're loading these structures, they tend to hurt. When you offload them, they tend to not hurt. So if the patient doesn't describe a mechanical component, the pain just comes and goes when it wants to, there isn't really a position that makes it better or worse, that may be a yellow or a red flag that there may be something else going on. Things like tumors, they're not gonna necessarily have a rhyme or reason or hurt worse when they're loaded. They characteristically hurt worse at night or worse supine. So keep that in the back of your mind. If there isn't a mechanical component, there may be something else going on. You wanna figure out, is there a neurologic deficit? Because again, most back episodes are gonna be self-limited. It can be treated conservatively. But once we have a neurologic deficit or even a progressive neurologic deficit, that again ups the ante. And then we think about surgical treatments. Is it one problem or multiple? So Oakham's Razor would say that if a patient has pain in multiple areas, we try to explain it by one diagnosis. But a lot of patients do have multiple musculoskeletal pathologies and they play into each other. So for example, if someone has hip osteoarthritis, that may affect their gait, how they're walking, their posture, that may cause strain on their back. So the back pain may or may not be referring to the hip or they may have a separate back and hip problem. When it comes to the differential of back pain, it can be something as simple as a lumbar sprain or strain. And by definition, sprain involves ligaments, strains involve muscles, and you do have a lot of muscles and ligaments in the low back. This should sort of be a diagnosis of exclusion. However, because a lot of these other diagnoses can present in such a way that it may mimic a muscular or ligamentous injury. The disc is certainly implicated in a lot of causes of back pain. Some studies would suggest maybe up to 40% of low back pain is discogenic, depending on the age group you're looking at. When it comes to the disc, what can be wrong? You could have a tear of the annulus, which is the outer ligamentous covering of the disc. You could have a disc herniation. You could have degeneration of the disc. And we'll go into a lot more detail on this later. Facet joints are certainly implicated very often in back pain, especially in older individuals. Facet joints are synovial joints, just like a knee joint. So anything that can happen to a knee can happen to a facet. You can sprain the joint. You can get an effusion. The facets have menisci or meniscoids, also similar to knees. So you could have a meniscal injury. You could have injuries to the capsule of the facet joint. And with advanced age, you can develop osteoarthritis in the facet joints. That's the most common cause of facet pain. Spondylosis is a term that describes overall spinal wear and tear. So in and of itself, I wouldn't necessarily say it's a pain generator. It's more of a pathophysiologic syndrome. But spondylosis encompasses both disc degeneration and facet degeneration. So if you have an older individual with sort of an aged spine, spondylosis is probably the best way to describe that. Instability or overload conditions, spondylolisthesis can cause back pain. And again, don't forget the medical illnesses, kidney stones, aneurysms, malignancies. And of course, some patients may have psychosomatic disorders that may present as back pain as well. Again, this is a diagnosis of exclusion. You wanna make sure you're ruling everything else out first. When it comes to buttock or limb pain, all radiating pain is not radicular. So radical means root pathosis problem. So radiculopathy is a nerve root problem. Sciatica is a term I try not to use, but if you look in Webster's Dictionary, sciatica just means pain going down the leg. So as medical providers, we think of radiculopathy as the cause of sciatica, but often the connotation is that it's an actual sciatic nerve problem. And true sciatic neuropathy is pretty rare. Piriformis syndrome may be one cause of that. That's also very, very rare, probably 1% of radicular pain or even less so. So someone could have hip joint arthritis, they could have greater trochanteric pain syndrome or bursitis, that can cause pain reading down the leg. Technically, that does meet the definition of sciatica, but the way we would think about it, it's not radiculopathy and it's not a sciatic neuropathy. So try to use the term that's most appropriate. So if it's a nerve root issue, try to use the term radiculopathy. But if patients wanna say sciatica, that's fine. Just wanna make sure we're talking about the same thing because a lot of patients will describe hip pain, they may be pointing to their back or they may describe back pain pointing to their hip. Technically, the back encompasses everything from the just inferior to the 12th rib to the inferior gluteal fold. So by definition, back pain includes the buttock. Other sources of either buttock or limb pain could be sacroiliac dysfunction, hip joint pain or other hip disorders, soft tissue disorders very commonly cause radiating pain on the leg and stress factors as well. Certainly spinal stenosis can cause radiculopathy. And when we think about stenosis, one of the thing about the region and where it's occurring because that may have implications to the kind of exercises we may prescribe for patients, the type of procedures we're gonna do or where we're gonna place our needles if we're doing a procedure. So stenosis, typically we break it down into the central zone, the subarticular or lateral recess zone and the foraminal zone. Okay, so moving on to the physical exam. The structures you wanna assess and this is how I approach all musculoskeletal issues. I try to do it in a systemic fashion. So you wanna think about the bones, the joints, the discs, ligaments, tendons, muscles, bursae and nerve. So these are potential sources of pathology and things that you wanna try to assess whether it's on history or physical. Now certainly some of these structures are deep and you can't palpate a disc, but we try to do different maneuvers to ascertain which of these may be causing pain. So a good mnemonic I picked up when I used to work at Mount Sinai, so shout out to the ICON School of Medicine there. When we taught our medical students how to do the exam, we used a mnemonic I promise because everyone promised to do a really good job. So I know everyone listening is gonna do a great job the next time they examine a lumbar patient. So the I promise stands for inspection, palpation, range of motion, and then the neuromuscular exam, which is gonna be the reflexes, sensations, strength, stability of joints. So in the spine, you can't really assess spinal stability on a physical exam, but it's something you wanna think about as far as your differential. And for other joints, certainly shoulders, knees, you wanna assess stability. And then finally, special maneuvers. The special maneuvers are the least important thing. The basic physical exam is really the most important. And again, the key here is figuring out is there a neurologic deficit, because that's gonna kind of up the ante and may suggest a more significant injury that may need further workup and treatment. So the things I'm looking for, I'm looking for the alignment of the patient, what's their posture, is there any gross deformity? Naturally, we have a cervical lordosis, thoracic kyphosis, and a lumbar lordosis. Here you can see this patient has straightening of the cervical spine and straightening of the lordosis. Often when you read an X-ray report, they may say, you know, consistent with muscle spasm or suggest muscle spasm. A lot of times this is just how the patient is standing or how the film is taken. You know, I'm not sure what muscle would spasm to create a loss of lordosis, but I'll leave it to you to think about. The longest coli, which is one of the deep neck flexors, it's been implicated in chronic neck pain, and weakness of that may lead to loss of lordosis, but that's more of a weakness than a tightness. You always wanna look at the joints above and below, so when we're talking about the lumbar spine, the next joint in the kinetic chain below is gonna be your sacroiliac joint and then your hip joint, and the more proximate is gonna be your thoracic and your cervical spine. So anytime I'm examining someone with a back issue, I'm always looking at the hips and vice versa. I'm gonna look at muscle bulk, size, symmetry, is there any atrophy to suggest, say, a chronic radiculopathy, and the range of motion is very important. With lumbar pathology, I'm typically doing active but not passive range of motion, but a real key to any back disorder is figuring out what the patient's directional preferences are. So what direction do they bend in that makes their symptoms worse, and what directions can they bend in to make it better? Because this has a lot of implications to what the diagnosis is, but also to what the treatment is. So for example, a classic central disc herniation is gonna hurt with flexion and feel better with extension. So if right now we're doing a lot of telehealth and we can't see patients in the office, so one of the ways I'm trying to help patients remotely is figure out, okay, do you feel better in extension? Then verbally, I'll describe how to do some passive extension exercises, and that'll take pressure off the discs and reduce either their actual pain or some of their radicular symptoms. So this can be really, really helpful. Are there any objective signs of inflammation? Most lumbar issues aren't necessarily gonna present with warm, swelling, redness, pain, or certainly pain you'll notice, but for peripheral joints, you're gonna see this. So if there's inflammation, say, of a disc or facet joint, you'll never had a patient whose back felt warm from this, maybe warm for other reasons. Crepitus, a lot of patients complain of crepitus in the back or clicking. Often that's related to subtle subluxation of the facet joints or SI joints. Typically that's benign and not a real source of pathology, but patients certainly are troubled by it. So you wanna address it, you wanna just dismiss it, and that way the patients feel like they're being listened to and heard. Is there any focal tenderness? This can kind of steer you off track because regardless of what the problem is in the back, a lot of patients will have paraspinal tightness, and that's the body's way of compensating, protecting them. So just because someone has tenderness over the back muscles doesn't necessarily mean it's a muscular issue. You can see tenderness whether there's a disc problem, facet joint problem, or just a muscular strain. Patients often are gonna present with weakness, and it's really important to determine, is this pain limited or neurologic? And so for the residents out there, we won't accept an answer when you're presenting your cases to your attending, are they weak? Oh, well, I couldn't really tell the patient was hurting. It's imperative to do the best exam you can. Even if a patient is in pain, you wanna properly assess their reflexes, their strength. I ask them, just give me your one best rep, your best effort, and regardless of how much pain a patient's in, you should be able to get a good assessment of at least one rep to determine if there's true weakness or not. And if they have numbness, is this in a dermatomal or a peripheral neurodistribution? That may help differentiate a radicular pattern versus preferred pain for maybe the disc, muscles, or other structures. Now, for those of you that aren't familiar with, say, Travell and Simon's work, I encourage you to look at some of the pictures that they drew describing different trigger point referral patterns, because you'd be surprised a lot of trigger points refer in a very sort of pseudo-radicular fashion. So for example, someone who has a trigger point in the gluteus medius, it may look like an L5 radiculopathy. When we're looking at range of motion, in this graphic, they describe angles. If you really, truly wanna assess range of motion, you have to use the inclinometer, and that way you're assessing the motion of each individual spinal segment. So when I describe range of motion, I describe percentages of normal. And of course, this is gonna vary depending on if you're old or young, if you're flexible, if you have ligamentous laxity or not. So patients are trying to prove to you, hey, look, doc, I can touch my toes. And I explain to them, I'm looking just to see what provokes your pain and what makes it better. So the goal is not necessarily to touch your toes, because if you're bending your knees, or you're doing all the work at the hips, now you're not assessing lumbar range of motion, you're assessing knee and hip range of motion. I don't necessarily cue patients, because I wanna see naturally how they're moving, because adjusting these movement strategies may be a very simple, easy way of treating their back pain, at least in the short term, if not in the long term. So I have the patient bend forward, and you wanna assess, is flexion making their pain better or worse? You wanna do lateral bending, which typically would be uncomfortable or limited if someone had a disc problem. You wanna assess extension, typically for set joint problems are worse with extension or oblique extension. But as we talk about herniated disc, depending on where the herniation is, extension may make a disc worse if it's in the foraminal zone, versus a typical central disc herniation is probably worse with flexion. I'm also assessing their pelvic alignment and how that plays into their lumbar spine alignment as well. A lot of these concepts were described by Yanda, who is, I believe, a Czech physical therapist. And some of these were disproven, but I still think it's a helpful framework for assessing alignment, and also helps to inform the rehabilitation programs. So this is a classic patient that you may see with an anterior pelvic tilt. They tend to have, so the way I think about it is, what muscles are tight, what muscles are weak. So often these patients present with an accentuated lumbar lordosis. They have tightness of the psoas, quads, spinal erectors. Often if you palpate their lumbar spine muscles, they're really tight and hard. They may have quad lumbar pain or spasm, tight adductors. And then the glutes, the lower abdominals, and the hamstrings tend to be weak, lengthened, and inhibited. So if you think about a patient like this, they may have hyperlordosis. Think about the stress that puts on the posterior elements. That could be a risk factor for facet problems, or side joint problems, or just myofascial pain. So if you have a patient with this pattern, already you know what the rehab is. It's to stretch the muscles that are too tight, strengthen the muscles that are too weak. The posterior pelvic tilt, often I picture an older gentleman in a VA type environment with sort of pants pulled up to his waist, kind of like Urkel, for those of you that remember that old TV show, Family Matters. So often these patients, because they have this posterior tilt, they have very tight and shortened glutes and hamstrings. Often they walk almost with a bent knee gait because the gastrocs are so tight. Their abdominals also tend to be tight, but at the same time inhibited. This is where you want to differentiate. Muscles can be short or long, tight or weak. So just because something is tight doesn't necessarily mean it's shortened and needs to be stretched. And just because something's weak also doesn't necessarily imply if it's short or long. So when you're assessing these muscles, think about a rubber band. Rubber band functions optimally at its ideal leg tension relationship and it's not gonna work if it's too tight or too loose. Some of these muscles are tight because they're weak. And so if you strengthen them, they tend to relax. So they don't necessarily need stretching, they need more strengthening. A good example is often the iliopsoas muscles may be tight and often they're just overworked and hypertonic so it gives the posterior muscles like your gluteus maximus, hamstrings, those need to be strengthened. So often these patients with the posterior tilt, they're gonna assume that position because it creates relative lumbar flexion and that may be protective if they have spinal stenosis. But someone with a disc problem, this is not gonna help them and may make things worse. So radiculopathy is numbness in a dermatome, weakness in a myotome, decreased muscle stretch reflexes, and it's typically from a lumbar, I'm sorry, from a disc herniation, but it can also be from spinal stenosis as we get older. Lumbar disc herniations, because of the orientation of how the nerve roots come out, can affect multiple levels. So someone say may have an L4-5 herniation, but they could have clinically an L5 and S1 radiculopathy. In the C-spine, however, typically one herniated disc affects one level and one nerve. So if you have a polyradiculopathy in the cervical spine, then you wanna think about other diagnoses. For example, an inherent spinal cord injury or lesion, or a large herniated disc causing severe central stenosis affecting multiple levels, but typically, or a brachial plexus injury, but typically one level should be involved. Motor exam, this should be a review for everybody, but you wanna screen your key muscle groups in the lower limbs. So your hip flexors, L2, knee extensors, L3, ankle dorsiflexors are L4, great toe extensors, L5. S1 is plantar flexors. When I manual muscle test, I usually check the knee flexors because that, to me, is an easier, better way to do S1. You get a little bit of L5 and S2, but I think it's a good way to get S1. If you're in a manual muscle test, the plantar flexors, you might as well not bother. If you're gonna check plantar flexion, you should have the patient do single toe raises and compare side to side. So sensation, again, you wanna think about, is this a peripheral nerve distribution? Is it a dermatomal distribution? And check light touch and pinprick. Now, patients can have radiculopathy and it doesn't necessarily affect the nerve all along its course. So when I was first learning about this, I used to think, oh well someone has an S1 radic, they must have buttock pain, posterior thigh pain, calf pain, foot pain, but depending on the degree of or severity of the nerve injury or if the symptoms have centralized or peripheralized, they could have only buttock pain and that could be an S1 radiculopathy or it could be only foot pain. So peripheralization is when the patient feels it further down their leg and centralization is when they feel it less down the leg and closer or approximately to either their buttock or their back and that's one of the ways you can tell the patient they're getting either better or worse. So someone presented back pain and then a couple days later it starts going to the buttock, a couple days later goes to the calf and then foot, they're probably getting worse. That same patient then starts to feel it only in their calf, then the hamstring, then the butt and then it goes away, that's a sign of healing. And you can use some of those tricks as you're teaching patients exercises to try to self-manage and figure out what that directional preference is to reduce pain and irritation of the nerves. Your key sensory landmarks, anterior thigh L1 and L2, medial knees L3, medial ankle L4, your first web space L5 and your lateral heel or the sole of the foot S1. Now careful as you're examining the foot because the foot has elements of both L4, L5 and S1, so the patient has foot complaints, it could be any one of those nerve roots. These are some of the classic referral patterns when we think about radiculopathy. It's important to also know the epidemiology and the incidence of these conditions. L5 and S1 radiculopathies are by far the most common levels. Once you get to say L3, it's less than 10% of all radiculopathies. So if you're diagnosing a lot of L1, L2, L3 radix, either you're seeing a very unique patient population or you may want to think about your diagnosis. So this was a study recently published by one of my mentors, Dr. Furman, and I thought it was a really neat study. So what he did is as he was doing epidural steroid injections and injecting contrast along the nerve root, he would ask the patients to draw on the diagram where they felt their symptoms. And interestingly, regardless of the nerve root level involved, there was a lot of overlap with symptoms. So for example, L3, we think classically, you know, L3 reproduces anterior thigh pain, but you can see a lot of the patients had posterior thigh pain and even posterior calf pain, almost mimicking an S1 distribution. If you look at L4, it encompassed the entire leg, both front and back. However, if you look at S1, patients only had posterior symptoms. So for example, if a patient presents with say buttock pain, based on these diagrams, they could have a radiculopathy involving L3, L4, L5, or S1. However, if they have anterior thigh pain, well now that probably rules out S1, but it still could be L3, L4, or L5. So take the referral patterns with a grain of salt. You know, I describe my job as being a detective. We collect clues and we build a case. Some of the clues may lead you in the wrong direction, but as long as the preponderance of evidence adds up, now you've got a diagnosis. Reflexes, most people know about the knee jerk L2, L3, and L4. Ankle jerk is S1. Long forgotten and one of my favorite reflexes is the medial hamstring. So this is a way to assess L5. This is so important because L5 radiculopathy is the most common level. So to check this, we basically tap on the medial hamstring. Typically while the patient is seated and you look for knee flexion. Now if you're resident and you haven't done this reflex before or you think you're not good at it, practice makes perfect. So you just have to try it on every patient. I encourage you to go to your spinal cord unit, TBI, stroke unit, find patients that have upper motor neuron syndromes that are hyper reflexic because it'll be easier to get in those patients and then you can take it to the outpatient clinics. Just make sure you're not getting an adductor response that you're actually looking for knee flexion. If you can't see it, you can always palpate and feel the knee flex. Palpation is usually the last thing I do on exam. You know a lot of lumbar spine issues that patients may or may not have tenderness to palpation. So I don't put a lot of weight in that but these are some of the key areas you want to palpate and their significance. Just for time I'm going to skip over this. One thing I will note is the sciatic notch. So this is the region of the piriformis muscle and it's an area where the sciatic nerve traverses through. Often patients with radiculopathy will have tenderness at the sciatic notch for reasons we don't fully know. So just because they're tender there doesn't mean they have piriformis syndrome. There was an old study that showed that patients with nerve root dysfunction could be tender all along the course of the nerve. So think about the next time you have a patient with an L5 radiculopathy, palpate behind the fibular head. Sometimes they have tenderness to that common peroneal nerve and this may be why they have tenderness in the sciatic notch because the sciatic nerve may be tender. I'm not sure. Okay so now moving on to your special maneuvers, straight leg raise, seated slump test, and the femoral stretch test are going to be your major special maneuvers. There are others as well but we focus on this for time. So the straight leg raise, the patient is supine. You're passively raising their leg and you can do this either with the ankle dorsiflexed or not. So typically the way I do it is with the ankle in a neutral position. You want to lift the leg until the patient says pain. The idea is that you're getting dural stretch and you're only really stretching the dura between 30 degrees and 60 degrees. So the patient says, ouch yeah I feel pain going down my leg but you're already flexed to 90 degrees. You're not actually putting stress on the nerve at this point so that may be referred pain from other structures like the SI joint. In order to accentuate the dural tension you can do the brackered maneuver. So while you raise the leg up, patient says they have pain, let's say it's at 50 degrees. If you then dorsiflex the ankle they should have worsening pain. If you then keep the ankle dorsiflexed but you lower the leg down that should relieve their pain. What some people like to do is they do the whole straight leg raise with the leg or sorry with the ankle already dorsiflexed and the toe dorsiflexed and then as soon as they get to the level of pain they release the ankle dorsiflexion. So there's both you know both are fine ways to do it. You know some people are taught the pain has to go below the knee. If the patient's presenting with only buttock pain and you reproduce their concordant pain that may be a positive test. So often what I'm looking for and the way I describe my findings on exam is concordant or discordant. An example I use with my students is you know if I punch you in the face your face is going to hurt. There's nothing wrong with your face until I punched it. So if I push hard enough in your back as I'm palpating or if I you know bend you like a pretzel or manipulate your nerves I may cause pain but if that's not your usual pain that may not be relevant. If you want to describe the concordant pain does it reproduce the patient's usual pain or is it discordant? But I still describe it because I still think there's useful information there as opposed to just saying straight leg raise positive or negative to me I get less information from that. But typically with the straight leg raise you're tensioning the L5 and S1 nerve roots so if the straight leg raise is positive it may suggest L5 or S1 radiculopathy. The seated slump test is very similar to this straight leg raise it's just done in a seated position. So you have the patient seated you then have them bend forward bend their chin extend the leg dorsiflex the foot and they should have radiating pain. As you pick their head up they should then feel better but I don't like how this is done. I have the patient do it actively I don't like to passively bend their head down forcefully. I don't think that's the most comfortable thing for patients. The femoral nerve stress test is a stretch test is a way to assess the more proximal nerve roots L2, L3, L4 and as the name implies you're stretching the femoral nerve so those are the roots that are supplied by the femoral nerve. Because L2, L3, L4 radix are so uncommon this test has limited utility but if you think someone has a higher level radiculopathy it may be helpful. Other things though can cause false positives so what you're doing is you're extending the patient's hip and then you're flexing the knee and you're looking for anterior thigh pain or paresthesias. Now this is also just stretching your rectus femoris muscle so if someone has tight rectus femoris they may have pain with this maneuver. Okay so moving on to some of the pathophysiology. Every time I talk about the spine I always describe the Kirkcaldy-Willis degenerative cascade and I think it's a really helpful framework to understanding spinal pathology. You know often when I give talks to other specialists, rheumatologists, general practitioners, you know they always lament you know what do you do with a lumbar MRI? Every time I get an MRI it always shows facet disease, disc disease, stenosis. It seems like every patient has every problem and as you understand spondylosis then it makes sense why and how the spine kind of wears out in a predictable fashion. Obviously just because you see findings on an MRI that doesn't imply that's where the pain's coming from. So when we think about this three joint complex, each spinal segment is made up of three joints. The first joint is the disc in between the two vertebral bodies and the other two joints are the two z joints or facet joints. So there are different phases that the spine undergoes and this entire process is called spondylosis. So in the initial phase there's a dysfunctional phase where you have injury or overload to the disc end with circumferential tears to the disc or perhaps radial tears that then puts stress on the facet joints which develops synovitis, hypomobility. Eventually there's excessive stress on the disc and the disc herniates. The next phase you're in the instability phase so now you're losing structural integrity of the discs and the facets to be able to weight bear and accept the load. So the facets develop capsular laxity, they may sublux, the discs may resorb or may herniate to a greater degree. This can lead to lateral nerve entrapment and eventually the body tries to stabilize. In this stabilization phase you may have enlargement of some of the bony processes like osteophytes, you may have facet hypertrophy or enlargement. What this does is then it leads to narrowing of the spinal canal and that can lead to stenosis. So here's a radiographic example of what that would look like. Initially you have increased disc forces, then you have loss of disc height, now you have increased load bearing of the facet joints which weren't designed to bear load and now you get facet dysfunction. So if we all hopefully live long enough we will all develop spondylosis and all of our spines are going to go through this process. So radiographically we're going to have features of all of this but clinically we're not all going to manifest with this. This is why you know having a good history in physical, having a good pre-test probability of what you expect your diagnosis to be before you just go on a fishing expedition and get imaging studies is so important. Because if you're starting with the imaging study you're doomed to fail because you're going to have multiple positives on that versus you know if you already have an idea of what the diagnosis is you get your imaging study just to confirm or rule out other bad scary rare things like tumors you're going to be better off and your patients will be better off too. So when it comes to wear and tear you're going to start with our vertebral end plates and work our way out. So the vertebral end plate is a cartilaginous covering of the vertebral body hypothesis and forms the top and the bottom of the disc. So with age you lose water content, the ratio of chondroitin to keratin changes, proteoglycan molecular weight decreases, you gain fibrous tissue, cartilage tissue, and amorphous tissue. So now these end plates are not able to accept the loads as well and that can lead to end plate dysfunction. So we're going to and that can lead to end plate injuries or end plate fractures which in and of itself can cause back pain. Often it presents similar to a compression fracture or acute herniated disc where often there was in it say a flexion rotation moment, patients had severe pain, tends to just be axial pain and it tends to improve with time. If those vertebral end plate fractures don't heal however you can have a herniation vertically into that defect and that's what's called a Schmorl's node. So now moving on to the disc. The disc is made up of your inner nucleus pulposus which is your viscous mycoprotein gel mixture of water and proteoglycans and a network of type 2 collagen and this braces the outer annulus which prevents buckling. The outer annulus acts as a ligamentous restraint made up of type 1 collagen fibers arranged and obliquely running lamella and lamella means layer so there's different layers. One way to think about it and is as a woven basket. So if you take a basket it can rotate and twist pretty well but it doesn't like loading and twisting as well and it's weaker for torsional stresses. So discs are designed to take load and a lot of patients are afraid oh you know I can't exercise I can't sit you know our discs are designed to take load but the discs don't like load and shear and that's true not only of discs but other cartilaginous structures joints. So same thing saying you know your knee joint the knee cartilage takes load very well especially cyclic loading when you're doing things like exercising running but acute overload like falling from a height and twisting as you would injure say your meniscus then the joints don't like that. So with an internal disc disruption you've got degradation of the internal architecture of the disc but there's no gross herniation. So you can think of this as sort of a pre-herniation. This is associated with annular fissures and nuclear tissue disorganization. On the right is a graphic of the modified Dallas discogram scale. So back in the days when we used to do discograms which are rarely done nowadays discograms were a way of diagnosing if there were internal disc disruptions are there disc herniations or annular tears that you couldn't see say on an MRI or other advanced imaging and it's a functional way of trying to provoke someone's concordant pain. So if someone did have a disc abnormality in the MRI you want to know is that the level that's actually causing your pain before you go in and do surgery. So this is how the IDDs were graded. The grading doesn't necessarily correlate with with pain or with outcomes so just keep that in mind but as as the disc is degenerating you know what's hurting. You've got nerve fibers that surround the outer annulus of the disc but the nerves don't grow into the inner aspect of the disc. So as you develop these disc disruptions or annular tears you now have new nerves that grow into areas that weren't previously innervated and then those nerves become sensitized by different chemical mediators that are released when there's a disc injury like cgrp interleukin one and six different prostaglandins thromboxanes etc. So now once a disc is sensitized you're going to start to feel pain and things that would normally not hurt the disc normal loading say sitting bending now that the patients have pain. So there's sensitization of both the chemical and the mechanical nociceptive fibers. This is a schematic of what the different types of disc injuries look like. So as you have fissures or tears within the annulus they can be in different directions. You could have a circumferential fissure as shown on the left. You can have a radial fissure or you could have peripheral rim fissures. You can't differentiate these on history or physical. This is just going to be an imaging finding. So what does internal disc disruption look like on imaging? Typically it's going to start with desiccation or drying out or darkening of the disc. However not all desiccated discs are painful and I'm sure we've all seen patients in the office. They come in with an MRI report. They're despondent. Doctor I'm drying out. I'm degenerating. What's wrong? I'm never going to get better. And you know one of my colleagues, you know Dr. Prescott I work with, uses the example that this is like gray hair at your spine. Just because you have gray hair doesn't mean there's anything wrong with your hair. It's just you're getting older. The desiccation or drying out of the disc is just gray hair of the disc. So it doesn't necessarily correlate with pain. That being said if someone has what you think is discogenic pain and they happen to have one dark disc on an MRI that may be a good target to think about as the pain generator but it's not pathognomonic or diagnostic. Other things you can look for are high intensity zones. So these are bright areas and I don't know if you can see my pointer but here's the high intensity zone in the outer annulus. That's suggesting annular tear or defect and these do correlate with annular tears on CT and discography and often they do correlate with pain. That being said only 54% of herniated discs have a high intensity zone. So if you see a patient with a high intensity zone you think they have discogenic pain it's likely that's probably the disc that is causing their pain. However if there's no high intensity zone it doesn't mean that that's not the disc causing pain. So now we're going to move on to disc herniations. Here you can see your central nucleus. You can see the lamella or rings like a tree surrounding it and here you can see this disordered nuclear material, sorry, wiggling its way through through these cracks and separations of the different lamella. Here you can see these small cracks or rents and separations within the lamella. So I used to think, sorry my mouse is very sensitive, I used to think a herniation meant that all this nuclear material squirts out through a tear in the disc here but that's not always necessarily the case. You know here you can see the disc is protruding beyond its natural border because the disc should really end about here and that border is defined by the vertebral body. So here the disc is protruding because this nuclear material is pushing through but it's not actually leaking into the epidural spacer canal. Sometimes herniations do that but not always. So we talked about how this releases a lot of inflammatory mediators, phospholipase A2, leukotrienes, prostaglandins. This is why steroids and NSAIDs work because they're anti-inflammatory and they work on all these chemicals released by the disc herniation. Most herniated discs tend to affect younger individuals, most commonly between the ages of 30 and 40. Certainly younger and older individuals can get it too but you know knowing the age of the patient really helps to risk stratify. You know if you have a patient who's a teenager and they have a back problem they're more likely to have something like a spondylolisis than a disc herniation. If you have a patient who's 80 and they have more chronic back pain they're more likely to have fist set problems than a disc problem. Approximately 75% of disc injuries do get better within six months to a year. Doesn't mean it takes six months to get better but you can reassure patients most of these do improve on their own. The highest prevalence of disc herniation the lumbar spine is at L4-5 followed by L5-S1 and in the c-spine it's at C5-6. Depending on where the herniation is it may press on different nerves and that'll lead to different types of radiculopathy. We'll talk more about that. When it comes to different types of disc herniation there's also a spectrum. There's two ways to describe it. There's an older terminology and a newer and I'll teach you both because you're going to see both as you're reading different MRI reports or seeing different patients. Disc bulging is considered normal and it's just a normal physiologic phenomenon. It's not considered pathologic so this is where the disc height is preserved but greater than 50% of the disc is beyond its normal border as defined by the particular body. Now as you start to get into herniations this is where these are pathologic these are not normal. A protrusion in the old system is defined by there's no or minimal annular disruption and so the disc herniation is contained still by the annulus. An extrusion is when there's complete annular disruption and an extrusion with a sequestration is that hole in the disc I was describing where the nuclear material leaks out as if it was a jelly donut leaking out. This is a picture I believe from Cucurullo which describes the same thing. The better newer terminology is the Farden classification and this was a consensus paper written by neurologists, neurosurgeons, physiatrists, radiologists, to try to come up with a more consistent system, because different doctors, different radiologists were describing these in different ways. So the way you think about a disc in this framework is that you can break the disc into either 25% or four quadrants of 90 degrees each. If greater than 50% of the disc is beyond its natural border, that's disc bulging, and that could be symmetrical, because here 100% of the disc is bulged, or if it's, say, just on the right, you could say there's disc bulging eccentric to the right or eccentric to the left. A herniation is when 25% to 50% of the disc, sorry, a broad-based herniation is when 25% to 50% of the disc is beyond its normal border, so this is a broad-based herniation, and then a focal herniation is when less than 25% of the disc is beyond its normal border. Whether it's a protrusion or extrusion, now you're looking at the base, so if the widest part of the herniation is the base, that's a protrusion, if it comes out like a mushroom cloud where the widest part of the herniation is not the base but it's somewhere further out, that's an extrusion, and a sequestration is when there's a free fragment floating in the canal. Now we're going to talk about where the herniations are and the different nerves that may be affected. So there's two gross herniation types, you can have a central herniation or a foraminal herniation. Here's your classic central herniation at L5-S1, so we can see here the widest part of this is at the base, sorry, so this would be considered a protrusion, and you want to look at that in three different dimensions. So here the widest part is at the base, and here the widest part is at the base. So we describe this as a central protrusion because it's in the central zone. The central zone is defined by the medial borders of the facet joints, and then your foraminal zone is defined by the facet joint itself here. The lateral recess and subarticular zone is here, and I encourage you to read the Fardon paper where they show some nice pictures describing what that zone is. But if you think about it, you know, think about being a nerve traveling on the nerve highway and where the exits are, and depending on, you know, where you are and where the herniations are, what nerves are going to be affected. So at L5-S1 here, these are your S1 nerve roots. Here the disc is not directly touching or compressing the nerve, so presumably this patient may just have back pain, or they could have a chemical radiculitis where they do have leg symptoms as well. So here's a right central herniation, a right central protrusion, because it's off to the right but it's still bordered by the facet joints. These typically get the descending nerve roots. So if this is at the L4-5 level, this is going to be affecting the L5 nerve that's descending. Your foraminal herniation here is going to be in the foraminal zone, and at this point, if this is L4-5, this is going to be affecting the exiting nerve root, which is typically L4. So this is why all herniations aren't created equal. If you see a question, say, on your boards or on the SAE, there's a herniation at L4-5, what nerve is affected? Most commonly it's the descending L5 nerve, but ideally you would want to know where the herniation is, because if it's central or subarticular, it's probably getting L5. If it's foraminal, it's probably getting L4. A good way to diagnose this is on a parasagittal view. So if you quickly scan an MRI and you just look at your mid-sagittal cut, you're going to miss this herniation. You have to go to the parasagittal cuts, and now you're going to see this focal protrusion here. So normally the nerve roots have a keyhole configuration where you have white perineural fat and a gray or dark nerve root. Here the disc is obliterating that perineural fat, so this would be severe foraminal stenosis. So disc injuries, often there's an acute injury due to either lumbar flexion or rotation. As the discs get pressurized, pain gets worse, so what increases the intradiscal pressure? Typically it's sitting, coughing. A good picture to memorize is a picture from the Nocumson article, which shows different discal pressures based on the position of a patient, whether they're supine, sitting, standing. Wink, wink. Sometimes that shows up on the boards, so it's good to know. It's also good to counsel your patients on what positions they may find more comfortable if they have an acute disc issue. If they only have back pain, maybe they only have an annular tear, maybe there's an end plate fracture or compression fracture, they still could have a herniated disc if there's only back symptoms. What's worse with flexion? Then you want to think of central herniated discs. These tend to be better with standing. If a patient feels better sitting, worse standing, that suggests probably a foraminal herniation, or maybe it's not a disc issue at all, it's something like stenosis. A lot of people prescribe, say, extension-based exercises as part of the McKenzie method or MDT, but again, all herniations aren't created equal, so the rehab shouldn't be as well. So patients with foraminal herniations, if you put them into extension, they're just going to be in a lot of pain. So moving on to stenosis. This describes narrowing of the spinal canal, and this could be congenital or acquired. So you could have a herniated disc that then narrows your canal, and because of that, have spinal stenosis, but the cause is the herniated disc. Certainly when the herniated disc resorbs and goes away, that stenosis is going to resolve, versus if you have an older individual where there's bony hypertrophy due to that spondylotic cascade, then the stenosis, at least radiographically, won't improve. That doesn't mean that their symptoms won't improve. The syndrome of stenosis is typically patients walk, have radiating leg symptoms, and when they sit down, they feel better. So that's called neurogenic claudication. That typically is from central stenosis, but that could be from foraminal as well. The pain is typically coming from neural compression, although there may be a component of ischemia to the nerve roots as well, where the vasonervorium, the small blood vessels that supply the nerves can be compressed, and you can have intramural edema, which can lead to pain as well. There are rare cases where patients will have spinal stenosis that presents only as back pain, but typically, they're going to have leg symptoms, and the most common cause of this is going to be spondylosis, ligamentous hypertrophy, osteophytes, facetal hypertrophy, herniated disc, as we mentioned. Facet joint cysts are not an uncommon source of stenosis, and of course, masses are going to narrow the spinal canal as well, tumors, infections, or hematomas. Facet joints, these are a very common source of back pain, especially in older individuals. They're really called the Z-joints or zygapophyseal joints, which are the posterior articulations of the vertebral bodies and the spine. Facet just means face, so you have facets in your patella and other areas in the body, but it's just easier to say facet, so it's okay, I won't fault you if you do. Etiology of this could be a whiplash-type injury in younger individuals, postural strain, but typically in older individuals, it's spondylosis. Here you can see the facet joints, and they're made up of the infra-articular process and the superior articular process. Each facet joint is innervated by two medial branches, one at the level of the joint and one at the level above. So the way we diagnose facet syndrome, what's considered the gold standard, is to do two diagnostic medial branch blocks, because history and physical can be a little bit unreliable. It's also helpful to know what the referral patterns are for facet joint pain. This is a classic study done by Dwyer where he injected facet joints, and patients drew where they felt the pain. And so you can see facet joint pain can cause groin pain, it can cause lateral hip or buttock pain, sometimes it even can cause pain down the leg, so it can mimic other syndromes as well. And often multiple levels are involved, but typically the lower spondyl levels are involved because they're going to weight bear the most, so often patients will have L4-5 or L5-S1 facet arthropathy. Depending on the studies you're looking at, approximately 30% of low back pain is attributed to facet joint pain. This could be up to 60% in older individuals, say about 65. In young individuals, facet pain is much less common, unless there's some sort of acute traumatic event, like a sporting injury, motor vehicle accident, et cetera. Okay, so muscular disorders, you know, these are muscular or ligamentous causes of back pain typically due to overload, and that could be acute or chronic overload. So if you have poor posture and you have abnormalities of the length-tension relationships to the point where, say, you have chronic shortening of your lumbar paraspinals or quadratus lumborum, then you may have chronic muscular pain. However, most patients with an acute injury, a sprain, strain, the back pain should get better. So typically patients are going to present with muscle aches, spasm, guarding, they may have delayed onset muscle soreness, you know, a couple days after a vigorous workout, there may have been an acute overload injury. Typically, they have a normal neurologic exam, and this can mimic an acute herniated disc and be very, very painful. But often you just reassure the patient, it tends to get better on its own. So if they have severe back pain, whether it's a disc, muscle, as long as there's no neurologic involvement, you know, often we're treating it similarly, trying to find, you know, positions of comfort, mobilize the patient, discourage them from bedrest, et cetera. Myofascial pain syndrome involves muscular pain, but more on a chronic basis. This is regional pain with local muscle tenderness and associated trigger points. Often there's poor posture, there may be a component of overuse, there may be trauma. Often this is associated with stress, poor sleep, this is different than fibromyalgia, but they often overlap and they're both part of your differential. These patients are going to have muscle tenderness, spasm, restricted range of motion, they're going to have trigger points, which by definition, when you palpate, they cause radiating pain. They'll have a normal neurologic exam, and again, these patients are going to mimic disc patients. So often I'm trying to avoid imaging as much as possible if there are no red flags, no radicular symptoms, because once you get an MRI, you're going to find abnormalities. In individuals over, say, 60 years old, over 70% are going to have an abnormality on the MRI. In individuals in their 20s or 30s, even up to 30% or more are going to have abnormalities. So often, you know, when patients have chronic axial pain, if you get an MRI, you know, you can use that almost as a rule out. If the discs look okay, then okay, maybe now we can determine this is myofascial pain. But even how the discs look, that doesn't really help you determine if it's discogenic or not. You really have to go by your history, your physical, or you'd have to do discography to determine if there really is discogenic pain, but again, that's very rarely done nowadays. So we're running out of time. I'm going to just go through the SI joint real quick. You know, it's interesting to understand the history of low back disorders, to kind of know, you know, where we were, to help inform us where we're going. So before herniated discs were described by Mixed Rembar in 1934, it was generally accepted that the SI joint was the source of all back pain and all radicular pain, and that's because the intimate relationship of the sciatic nerve and how closely approximated it is to the SI joint. Nowadays, we know that the SI joint pain is probably responsible for approximately 15 to 20% of back pain. Some studies show up to 26%. I'll tell you, in my practice, it's absolutely not 26%. It's much lower than that. SI joint dysfunction is very controversial, depending on who you talk to. It's the most over-diagnosed or under-diagnosed source of pain, but good controlled studies show that it's probably somewhere in the 10 to 15% range. The SI joint is stabilized by a lot of muscles, and that's really the key to treatment, is to try to stabilize and strengthen these muscles that give the SI joint its support. As far as referral patterns, most patients with SI joint pain are going to present with pain somewhere between the iliac crest and the gluteal fold. If they have pain above the iliac crest, it's never SI joint pain. If it's below the gluteal fold, though, it may be. So Fortin and Slipman did some of these earlier studies where they showed that either by injecting the joint and having patients describe where they felt the pain, or by anesthetizing the joint and describing the relief, 14% of patients with SI joint pain had ankle complaints, 12% had foot complaints, 28% had lower limb complaints, even 2% had abdominal pain. So most patients, 94%, had buttock pain, lower lumbar pain, but this can refer all the way down to the foot, ankle, and definitely mimic radiculopathy. Often patients are going to present with a Fortin finger sign, or if you ask them to point with one finger where it hurts, they tend to point right here. Physical exam can be notoriously difficult. Lazlet did a very nice study looking at different maneuvers. There was a study, I believe, by Slipman and Pausin in 1999 that did similar things. So in that 1999 study, of five physical exam maneuvers, four of the five had to be positive to predict SI joint pain. So that's SI joint compression, distraction, hip hyperextension, tenderness at the PSIS. Gainsland's maneuver was not one of those maneuvers in the Lazlet study, I believe it was. So I tend to not do Gainsland's. But of all those maneuvers, if you had to just pick one, tenderness at the PSIS was most predictive of SI joint pain. So if someone doesn't have tenderness at the PSIS, doesn't have a Fortin finger sign, doesn't have other risk factors for SI joint pain, which typically is ligamentous laxity, being pregnant or postpartum, or a fall onto the buttock, or seronegative spinal arthropathy or other rheumatologic condition, it's less likely that there's SI joint involvement. And that brings up a good point. I don't like to say sacroiliitis, because it implies inflammation. If someone has a rheumatologic disease, then I'll call it sacroiliitis, otherwise I try to use the term sacroiliac dysfunction, because often it's a mechanical perturbation than a true inflammation. Everyone's SI joint wears out and degenerates, just like all of our joints in the body. So you do not diagnose this by getting x-rays or MRIs. The diagnosis is made by a diagnostic injection and seeing a significant positive response to that. Imaging can be helpful if you think they may have sacroiliitis from a seronegative spinal arthropathy, or to rule out other things like fractures around the sacrum. But if you're thinking about SI joint problems, imaging is not going to help you. If you do want to image the sacroiliac joint, however, the way to do it is to get an AP pelvis radiograph or an AP lumbar spine, where they extend down into the pelvis. If you order SI joint radiographs, you're going to get obliques, and these are really just not helpful. So in summary, when you're approaching a patient with a back problem, you want to determine, is it back pain? Is it leg pain? You want to make sure you're on the same page with what the patient's describing. Is this a musculoskeletal problem, or is it another problem, like a medical issue? Is it axial, or is it radiating? Does it fit a root or peripheral nerve distribution, or peripheral nerve distribution, I should say? Are there red flags that require urgent imaging or referral? So these are going to be numbness in the groin area, a progressive neurologic deficit to a typically progressive weakness, severe intractable pain to the point where you need to be admitted with iphine morphine, or a history of trauma and potential spinal instability. Most episodes are going to be self-limiting and respond to relative rest, but try to encourage your patients not to undergo bed rest, but try to have them move and find what positions they find comfort in, and whatever light exercises they can do, try to mobilize them as soon as possible. Treatment wasn't really the goal of this talk, but we have a lot of options between chiropractic care, physical therapy, medications, injections, surgery, we'll save that for another day. So thank you so much for your attention, I hope you found this helpful, I'm happy to take any questions. Thank you very much. If anybody has any questions, please send them on over, I'm going to start with a couple of questions. First, real quick, I know we weren't jumping into treatment per se, but if you have a patient comes in with an isolated high intensity zone, you know, you've done the workup, you've done your evaluation, and now you've moved on to imaging, and they have this isolated high intensity zone, which I think is unlikely, you know, like you said, you're going to have all the gray hairs on an MRI, but are there any interventional options for that? Yeah, I mean, that's a common scenario, and it's tough. You know, for discogenic back pain, we don't have great interventions at this point. Some patients, because there's an acute inflammatory milieu, will respond to an epidural injection. You have to be cautious because epidural is really, you know, black and white, they're indicated for radicular pain. That being said, you know, if someone has axial pain from a high intensity zone, often they do respond to an epidural. The evidence in the literature doesn't necessarily suggest that, but I don't know a lot of good studies looking specifically at just high intensity zones and just disc injuries without radiculopathy. You know, there are intradiscal procedures being performed. I would consider that highly experimental, and I personally don't do them, and I would be cautious about doing them, but things like intradiscal PRP, there are ways to do intradiscal coagulation or electrothermy to try to burn those nerves that are growing into the annulus, things like biacoplasty. A lot of that is not covered by insurance because the results and the researches aren't great on that. So, often I try to reassure those patients that often those high intensity zones will improve or if not, at least their clinical symptoms should improve. Okay. Thank you. I think we have to move on, but I have one question just kind of to wrap up or kind of summarize your talk. Often, so we'll have the anesthesia pain fellows come through our clinic, and one of the first things they note is that everything refers to the buttocks, right? So I kind of call that rule number one of spine clinic is everything refers to the buttocks. So if you had to hang your hat on one aspect of all these things that you kind of summed up, so you get somebody comes in, referred pain to the buttock, you're thinking proximal radix versus, again, you mentioned the Dwyer study, referred facet pain, or referred SI joint pain, I know you noticed Steve Cohen's paper there, or Trevella and Simon's trigger point. If you had to hang your hat on something, you said, okay, here's what, you know, somebody comes in, a pain fellow or something like that and says, this pain referring to the buttock, are you going to say physical exam, are you going to say history, or is it just going to be kind of all of it together? You know, it starts with, for me, risk stratifying the patient, so not to be biased, but it helps to sort of dial in your differential diagnosis and the relative probabilities of things. So I'm looking at the age of the patient, what activities they're doing, and then I'm using history and specifically I'm asking questions regarding what either provokes your pain or what makes it better to determine, is there a mechanical component, is it musculoskeletal? And then based on that, I'm using my physical to really confirm and corroborate, and then imaging to further confirm. So if I had, say, a 30-year-old patient who was doing some sort of sporting activity, say they were lifting weights, and then all of a sudden they developed severe buttock pain, now something like a disc, plus or minus radiculopathy is going to be high on my differential. If I have a patient who's in their 80s, then something like facet pain is going to be high on my differential. But in general, for buttock pain, my differential is going to be disc, S1 radiculopathy, L5 radiculopathy, greater trochanteric pain syndrome, hip arthritis, SI joint dysfunction, way low down is going to be something like a piriformis syndrome. Okay, that's really helpful. Thank you. We are getting a couple more questions in, but unfortunately we're going to have to move on and we're kind of bumping up against our next presenter. Again, Dr. Kirshner's email is there. I think I have it pulled up here as well. There it is. So is it okay if folks reach out to you directly with some of these questions? Absolutely. Sorry for going over, but feel free to reach out to me via email.

low back pain

evaluation

management

diagnosis

causes

physical exam

special maneuvers

underlying pathology

facet disease

disc disease