In the time of COVID, primary care providers are seeing these complaints – and workers’ comp claims – virtually every day. UCSF orthopedic surgeon Nikki Schroeder, MD, reviews wrist and elbow nerve anatomy, presents the evidence on risk factors, explains the variability of the diagnostic process, and provides ergonomics recommendations to offer patients with desk jobs.
thanks for having me. I appreciate the opportunity to come talk Thio, all of you. Unfortunately, I can't see you. This is what I look like without my mask, but certainly seen an influx of, uh, both specific and non specific upper extremity symptoms on diagnoses in the setting of Kobe and working from home. So hopefully we will go over a little bit about ergonomics and how it relates to work related injuries, etcetera. So as an outline will go over some anatomy and path of physiology of carpal in cubicle tunnel on, then we'll actually talk a little bit about the clinical conditions. And, of course, when you talk about carpooling Cubanos on all, you do have to kind of reference repetitive strain, especially in the setting of, uh, work work related injuries. Um, and then we're going to go over some literature, review just specific toe work workers comp as well as thio, ergonomics, um, and then just briefly discuss some treatment options. So if you think way back to medical school in thinking about the anatomy of just a nerve in general, I do think it's a good reference point when we talk about nerve compression that if you remember, when you look at this picture on the right that the nerve is surrounded by the EPA Nouri, um, which is the outer nerve layer? Aan den. The paranoia Reum is actually what surrounds each fast ical or group of axons that you see here on Brendon Urie, Um is the loose college and matrix that surrounds each one of these. And so when we're talking about a nerve, we're talking about a group of fast sickles together. The inventory, um, is typically what we see when we do a carpal tunnel release. And this is the layer that we're usually doing a nerve repair. Like if you have a nerve laceration on Ben, the mile in and the Schwann cells make up the outside, which helped with the conduction. So just as a quick reminder, you see this picture of the rest, particularly the carpal tunnel. So when we talk about the median nerve, what I'm really talking about today is that the level of carpal tunnel where the majority of the pathology and the median nerve occurs, Um, and there are 10 structures that run through carpal tunnel, the median nerve, and then the flexor tendons to the fingers, as well as a flexor to the thumb. The Fbl Now the reason that we talk about carpal tunnel is mostly related to sensation, but also to the motor recurrent branch, which is the branch that provides the motor function to do most of the functions and the thumb to get the thumb out of the palm. Which is sort of what makes us human. So motor wise when you think about what the median nerve innovates approximately in the forum and innovates a flexor pro NATO mask, a swell Aziz Most of the FDs, which allows you to flex the fingers of the pipe joint. The branch that comes off just below the elbow is enter and Brosius Nerve, which allows you to flex the thumb. So that's the F P El Aziz well as the FDP, which, if you recall, flexes the D. I P joint of the index in the middle finger on it also does a perimeter Cuadrado's, which, which is that small little square muscle over the wrist, which is what we dissect through when we put on a plate for a distal radius so in the hand it does the 1st and 2nd lumber calls a zwelling most of the function functions of the thumb. So if you remember med loaf so it does the 1st and 2nd lumber coals that DNR's, um And it does half of the addict erso sensory. And you can see in this picture here, right? Everybody remembers that it does thumb index, middle finger and then half of the ring finger. Because, as you can see from the image here that most nerves have a common digital nerve that then splits into the radio Mullner Digital nerve proper of the finger and then the owner side here, This is the owner nerve. Now what you probably remember from anatomy is it gets kind of the fingertips of the index middle in half of the ring. And the reason it does this is that right? About the d i p. Joint of the finger? It tried the nerve itself try for Kates and sends off branches to the dorsal aspect. So that's why the media nerve covers the back of the finger. Now. Other things that are kind of critical in the setting of carpal tunnel is when we do a carpal tunnel release The goal is to release that transfers Carpal ligament, which is that thick band of fashion that lies right over the nerve right? That's what gets either thickened for reasons that we don't know or related to the theology. But that's what we're cutting when we're doing a decompression, whether you're doing it endoscopic or open, Um, and the thing that is most worrisome during the surgery is that motor, a current branch which lets you move the thumb, and the reason why is because most of the time, and if you look at this, you can see that it's it's extra ligament. It's so that's the most common. If you look at the literature, though, it's only somewhere about 40 to 90% of the times extra look momentous, meaning it comes off after the carpal tunnel. But you will always find those instances which I did yesterday, where the nerve may poke through the transverse carpal ligament. Very rarely does it come out before, but these air always reasons that you have to be concerned and not just say, Oh, it's a very easy, you know, carpal tunnel released. We need to worry about this nerve because it Sometimes it does pop through in places where you're not expecting it on Ben, you know, if that nervous cut is when you lose a function to do to some to get the thumb out of the palm so onto anatomy, the ulnar nerve of the cubicle tunnel. So primarily we're talking about the elbow because that's where most of ulnar nerve pathology happens. Um, there really are somewhere between five and seven sites of compression, and you can see that in the diagram over here, which shows you the sites. So basically, here is the ulnar nerve coming down. It courses behind. You know it's your funny bone, as we all know when you hit it, it hurts. But the nerve comes from behind, and then it splits here, and it dives through to come in the owner aspect of the hand. Most of the time, when it gets compressed, it's compressed at the elbow or the cubicle tunnel on DSO. It's between the medial epic condo, all of the humerus on, then the electorate on. So it sits behind it most of time. It hangs out there. Sometimes it does sub lex eight and what we mean is that when you flex the elbow, you can kind of see a bounce up and down. Um, and that happens in about 20% of the population. It doesn't mean that they have an increased risk of developing cute little tunnel. It's just something to be aware of, and it sort of changes are operative management, and we'll go through that a little bit later. But most of the time it's entrapped here and whether it's entrapped, because there might be an osteo fight on the back of the media. LPA Kanda Orphan pictures Sometimes they will get sickening of that. Push your aspect. Ah, the ligament here Or maybe just in the setting of arthritis, it can get stuck up here. So that's what you're seeing in this picture is all these sites, and it can get entrapped here as it splits the two heads of the flexor carpi onerous muscle. So the reason why you get nerve entrapment at this area is, as you can see in this picture with the elbow extended. So here's your leopard on here is your humorous in the media of a condo, and this is the owner of this black dot Here an extension. Osbournes Ligament, which is the roof of the cubicle tunnel, is nice and loose right on the nerve could breathe. And then this is the medial collateral ligament, which is actually the floor of where that nerve sits. However, as you start to flex the nerve and you get past 45 degrees, look how taught this ligament becomes and you can see that it's just smashing. What used to be circular makes it nice and flat, right? And so that's how you get entrapment. So that's why when you flex your elbow, not only are you stretching the nerve just because the distance you're stretching it, but it's also getting compressed. So again, anatomy of the older nerve, remember it innovates the owner side so it does the pinky finger reliably and then usually the owner side of a small finger, both on the volar endorse al aspect. So on the volar cider on the palm side, it comes from the owner of proper as it comes up through the eons canal, and then the back of the hand is actually innovated by a censoring her, which comes off about five centimeters proximal down here, where my arrow is pointing. So a review of path of physiology, of nerve compression. So compression happens when the nervous pushed on and it goes above normal cap Ilary profusion pressure so acutely it effects the micro circulation. A zit goes on for longer. You could get intramural DeMARE swelling in the nerve and inflammation. And then finally, you get these histological changes, which cause fibrosis or externally generation and de Milo nation. So that's what happens after a long time under compression. So what happens to those Schwann cells? Well, it alters their myelin nation on den. They could go onto apoptosis probably way too much, so we don't even need to talk about today. But this is a nice diagram, and it shows you that the history pathology symptoms usually follow the history pathology. So the beginning, when you just have, like a cute or sub acute compression, you get blood nerve barrier breakdown and then you get that a demon. And as you continue, we talked about you get fibrosis, right? Connective tissue thickening localized fiber de Milo nation on then diffuse de Milo nation. So, as you go around, the circle here is getting more severe and then, if you look at the symptoms you'll see initially, you get just intermittent para seizures in the distribution of the nerve. Then it goes on to constant. As the connective tissue starts to vibe. Rose on Bennett goes to full numbness and atrophy. And then what it's talking about in the inner circle here is that this is a sensory testing. So this is basically saying at the beginning you will have those positive, provocative maneuvers, which we'll talk about later. So you may have, like a tunnels or a Fallon's or a compression test. Um, as it go goes on, you will have a normal threshold testing, and then finally, you have an abnormal to point discrimination. So that's why the two point discrimination, if anyone is doing that, is where you know you check to see if they can tell the difference between one or two points when you touch them, but that's really coming as further on and the disease. So that's why when you see somebody that can't tell you the difference between one and two points, that it's actually been going on for quite a while. So causes of compression could be related to like an external compression. So if you have seen a Vitus, so if you have tendons were swollen for any reason that compressing the nerves and carpal tunnel or the elbow, you could have a mass effect from a tumor. Ganguly and things like that vibration has been known to cause it increased. Gripper pinch actually increases the pressure in the carpal tunnel. If you have any type of scarring, which can cause poor gliding in that area, and then, as we mentioned before, joint position eso with a stretched with nerve stretch or elbow flexion, you could decrease the space. Other causes. You can certainly see a double crush syndrome, which is when compression of the nerve at one level leave susceptibility to damage it. Another level. So we often see this as hand surgeons when somebody comes in and they may have mild, moderate cervical stenosis, causing symptoms on, then they have a lower threshold for having symptoms related to carpal tunnel or Cuban tunnel. So just moving on to the syndromes, um, carpal tunnel. It's compression of the media. Nervous. It passes through the carpal tunnel. The peripheral nerve compression causes reduced blood flow and impaired axonal transport eso. Basically, the nerve is a conducting, as it should be. And basically you end up with areas of Paris E jys or diminished sensation or even numbness in the area that you see in the picture here. Um, so the classic presentation, as you have all seen eyes, numbness or tingling in the radio three distributions, they will typically complain of nocturnal symptoms which awaken him at night. Um, you know, I think that that's a hard thing. Thio Discern. These days, as many people are taking sleep AIDS or many people might be taking pain medication for other reason. And they tell you they don't like up for anything at all. But usually if you elicit a history, they will say, Oh, yeah, At some point I would wake up at night, And there's also something called the flick scene, where they say that they shake their hand like this. Um, that is positive for carpal tunnel symptoms. Sometimes they complain about dropping things, not being able to hold heavy objects like pans or difficulty discerning small objects. So a za parallel to what you might see in, uh, knack pathology, they may say, you know, I can't tell the difference between a quarter and a penny in my pocket. Alright, prevalence is about 1 to 5%. It's certainly more common in females about 3 to 1 ratio. 50% of people end up having bilateral symptoms usually see it in the later decades of life. Now, risk factors will go over these two. There's just being females considered a risk factor. Um increased B M is a risk factor. And then there's certainly other co existing conditions, such as diabetes, pregnancy, rheumatoid arthritis, hypothyroidism on, then what we'll talk about later is hand wrist repetition. So when you look at the Ortho guidelines, this was published, I think, in 2000 and 16, Um, and what they did is they go through and they look at all the clinical guidelines related carpal tunnel, and they show you what has strong evidence, moderate evidence and limited evidence. Um, and what they can correlate very well with carpal tunnel is a high B m I and high hand wrist repetition at work. So these are the two things that they have strong evidence, and what that really means is that they have good studies that it's replicated in multiple studies, moderate evidence, these maybe not great studies. Not enough studies, Um or maybe, uh, some inconclusive evidence related to rheumatoid arthritis and then certainly psychosocial factors. I think it's worth mentioning that psychosocial factors play a big impact and upper extremity pathology. There is a high correlation between depression and anxiety and upper extremity manifestations on again. You can see it in gardening. Uh, this is high hand activity level, assembly line work, computer work, vibration, tendonitis, full group exertion at work and then a wrist ratio. So this is actually looking at the risk depth to the whip and then very little evidence in distal radius fibromyalgia, very ecosystem dialysis. And so this again just goes into what kind of is conflicting out there. So while we do typically say that diabetes, age and gender can be associated with it, there's just conflicting data out there from studies that have been done. So there's no really gold standard for the diagnosis. A carpal tunnel. Um, it's typically a combination of history, physical exam and diagnostic testing. And I think if you ask every single hand surgeon how they work up carpal tunnel, you might get a different answer. Andi. It just really depends on the symptoms that we put together with the physical exam on, then what type of testing we do at our facility or what we have trained in doing. But most of the time, what you see is some type of history and physical exam, depending on how reliable that is. You go on to get further testing, such as nerve testing. Some people are getting ultrasounds these days. So one of the criteria that I use eyes the CTS six um, which is a combination of both symptoms and physical exam and their questions that are asked to the patient and then exam that is done. And then basically you total up the number Onda total is 26 if there's greater than 12 points, the probability of having carpal tunnel syndrome is 80%. And so these air Siris of questions that I always ask in my history, I say, you know, when you have numbness and tingling, can you show me what fingers there in? Do you have night symptoms? Does it wake you up at night and you shake your hands? Then on exam, you're looking for atrophy and I talk about atrophy. It's theater atrophy in the A P B, which it will go over in a second bond. Then you're looking at provocative testing, one of which is a Fallon's test loss of two point discrimination. So if you do two point discrimination, you can check that and positive tunnels. Now it's a most people don't do two point discrimination. Probably many of you out there are not doing that. But you can see that even without even doing that, you can see the probability that number could certainly be greater than 12. So this is a cat's hand exam, which has described to think in the early nineties just where people diagrammed. And it shows that the most common presentation for carpal tunnel is this distribution here, which is the radio three digits. But you can certainly see that the pattern can be all all digits here on physical exam. We're really looking for a PB atrophy. And so, as you can see in this picture here, these air, the thing, our muscles and the A P. B is the most radial muscle on when I tell my residence is when you look at the thumb in this position. It's the most radial one. And really, you shouldn't be able to touch the bone on the side of your hand where that is on the Palmer side. If that. If you could see it or if you can really touch it, then it shows a PB atrophy. Sensory is diminished in the median nerve distribution. So over the thumb index middle on half of the ring. Um, and then what you're looking for is strength testing for the A P B. So you can see in the bottom picture. Here is this is what the A. P B. Does so the a p a p bee right abductor policies. Breakfast is palm early, abducting the thumb. And then there's all the provocative tests. There's Fallon's to now and then the Durkin compression test. So the Fallon's is where you reflects the finger. The tunnels is when you're tapping over the carpal tunnel here on Durkin's actually just pressing right where I say here and you compress for up to minute to see if it reproduces symptoms. So, um, nerve compression testing their elected diagnostic. Basically, what we're doing is we're trying to see if there's damage to the myelin sheath, which causes distillate, NCI's and slowed conduction velocity eso With prolonged compression, you see external damage, and you can see a decrease in the nerve amplitude. Really, what? We look at the numbers and you look to see if the distal motor late and see is greater than or equal to 4.2 or the sensory is greater than 3.2. Then that's diagnostic of carpal tunnel. But as you can see, the sensitivities could be pretty low for this. But this is still considered the gold standard. So moving on to Cubicle Tunnel, which is second most common peripheral nerve compression, the incidents is much lower than Chemical Tunnel, and it's carpal tunnel. It's more common in men ideology, so most of the time it's idiopathic so compression. We don't know why there may be a mass. You rarely see something associated with the elbow. Oftentimes we'll see it in the setting of trauma. So when somebody who may have been hit in the elbow that has, um, developed scarring around the nerve elbow arthritis, you'll see it. And then there's a question of repetitive elbow flexion. So again, when you think about the ideology. What you have to think about is what causes the compression right on dso you're looking at, um increase compression and decreased vascular garrity, which causes problems in the nerve. Um, and there's a combination both so you may see somebody that has a predisposition to it. So they may have a family history or they may have a congenitally narrow carpal tunnel. Um, they may have some type of job that causes repetitive compression, and they may have some psychosocial factors that contribute to this. So on physical exam again. Look at the neck elbow. Um, on the hand in Cuba, Hassanal, you're looking for wasting or Klein. So when you look at this hand here, this is an example of severe owner nerve atrophy. So look at the back of the hand. This is where the dorsal Interros er, this is the first dorsal in Rasiej, so you can see the scalloping in between. So this is showing in our Aussie. I asked fear, intrinsic atrophy, um, signs that you may see Wartenberg sign. You may see that the small finger is drifting away and they can't pull it back in. Andi, this is a sign for all their nerve, right? You can see it in the picture here, on the right. So it's the abductor for the small finger isn't working. And so it's drifting away. Um, Frohman sign. So remember that it does the adductor of the thumb. And so, um, you get compensatory flexion of the I p joint of the thumb to try and compensate. So if you put like a piece of paper in between someone's finger and try and pull it out, they will bend at the I P joint, which is using the media nerve to try and hold it in. And then masses sign When you look at your hands head on, you can see that there's an arch to the hand. When you lose, the intrinsic sit flattens out so you may see someone with a really flat hand. So here's the Frohman sign and then on physical exam, what we're really doing. You take the elbow through range of motion. Um, you look for evidence of arthritis on imaging or instability, and then when you flex the nerve up, you're looking to see if the nerve sub lock states, which means that it goes from behind the elbow to in front of the elbow. If they have tenderness to PAL Patient, you could palpate over the media pecan dial in a provocative tests, which is usually a flexion compression test, or a tunnels where you tap the elbow to see if it reproduces their symptoms and then you can check for strength. So when I check for Index for older nerve strength, you're doing that in a Rhoshii, so this is a way to check for it. It's having good, the piece on and see if they can pull their finger out. What I prefer to do is just do it with the index finger because the first dorsal interracial, which is this muscle here, as we saw in that picture before, is actually much stronger than all of the other ones. Um, it's just much easier to say. Point your finger this way and hold it there. And this is a much stronger Ma, a soul than the other. Interesting. So it's a little bit easier to assess. Oftentimes, people ask you, why is that hand so much weaker than the rest of it and alter nerves? So the intrinsic stand, the sensory fact bass tickles, Um, which are, you know, the acts on bundles are actually closer and more superficial than the A, F C U and F D P. So that's the wrist flexor and the finger flexors. So that's why those don't get nearly is, um, when you have older nerve compression of the elbow. You usually see hand problems first before they start to complain that they have weakness with four inflection or finger flexion. So I think you have to talk a little bit about repetitive strain injury, and I feel like although I can't hear you all, everyone's kind of groaning because you guys probably are dealing with it even more than we are. Um, but this is really a spectrum of disorders, right? You know, it's carpal tunnel in cubicle tunnel, so it's nerve compression. It's a tendinitis that could go all the way from the next to the shoulder to the elbow, to the hands on. Its relatively defined is either specific or non specific, so you see it in adults of working age. Um, typically women greater than men. The prevalence is about 5 to 10% of the general population and up to 40% specific groups. The main cost of workers comp If I saw this, uh, can range anywhere to 5 8000 total of $6.5 billion every year just in the United States alone. Um, from workers compensation related to this. Um, interestingly, enough, RSI was first described in Australia in the eighties. There wasn't anything to describe this before, um, risk factors. So it's repetitive motion, poor posture and inadequate strength. And there's certainly a large contribution of psychosocial factors associated with repetitive stress. So there's high workload, um, stress related to that low job security, little support from colleagues and physical or psychological Excuse the spelling here, um, demands. So as you know, during Coben, we've certainly seen a lot of this. Andi, I think that this is you know, you can see a little bit of contribution of every part of the stress related to Cove it and what's going on in the world today that causes it to increase alone in the psychosocial factors. Not to mention you know what's going on with the physical factors of the home ergonomics. So on Ben. Certainly, individual factors complain to this, so there are several hypotheses out there on repetitive stress injury, but none of them have been strongly supported by scientific evidence, Right? So I just want to tell you what these theories are. But not one of them is that there might be continuous contraction of muscles with insufficient breaks in the workday, which causes reduced circulation and muscle fatigue and caused, um, may lead to a low level pain response. Another one is just overuse of tendons. By rep. Repetitive loading could lead to decrease elasticity or friction between 10 and and on the tendon sheath and then tendon fatigue over time. And then, finally, there's mechanical overload can destruct. Function of the nerve on DSA Pacific Lee This is forearm, wrist and finger posturing that can cause us, and any external pressure on the problem could increase in the carpal tunnel, uh, increase carpal tunnel pressures. So again, as I mentioned classifications, so there are specific disorders that could be associated with the predators. Stress. So that's just basically giving a diagnosis toe. What? Something what somebody has so they can have rotator cuff tendonitis. We certainly know that we're seeing a lot more lateral media of the candle itis cubicle tunnel. Carpal tunnel, Radio tunnel, declare veins. Um, both fuller and dorsal. Tina Sina, Vitus. So either the flexor, there's an extensive the wrist. And then we do see some Beyonce, which is compression of the nerve of Theo Nerve at the hand. And then there's a non specific disorders, which is really a diagnosis of exclusion, which makes it a very hard diagnosis to give. Because as we all know, you know, patients do wanna walk out of the office with a diagnosis now just a diagnosis of, like arm pain. So treatment, I just left the side pretty empty because it's usually therapy for almost all of these conditions. So getting onto the part that, like we really want to talk about are these syndromes caused by work? Onda, remember those slides that I talked about earlier, which is in the guidelines for a OS? And so I just wanna highlight this stuff. So we have strong evidence that says hi bm ir obesity is linked to carpal tunnel. This is only for carpal tunnel. I'm not talking about cubicle tunnel. There any really good studies out there and high hand wrist repetition of work. That's strong evidence So that's we could say that and then moderate is all of these other things. So forcible, grip related toe work, vibration, tendonitis. They might cause carpal tunnel. But we don't really have great evidence to support this right. Factors that show conflicting risks are all of these other things, which again you can see the workplace, right? So it really depends on the study. So the way that I like to think about it is you have to think about carpal tunnel is really an occupational sentinel disease, which is defined a disease that signals a need for preventative measures in the working environment. Right? So there's really two types of these. There's diseases that are almost always caused by occupational exposure. Right? Mesothelioma is almost always caused by a specialist exposure. And then there's diseases like carpal tunnel in cubicle tunnel, which may, because by occupational mechanical exposures, Andi those. That's kind of what we're talking about when we talk about repetitive stress, right? These diseases may be caused by occupation or maybe caused by your economics at work, but there's also other factors that may contribute to this, so it's a little bit harder to prove this So if you look at the data, um, there's a Danish cohort study, and apparently nobody leaves Denmark so you can assess people for years when you look at this. But they looked at all of these jobs and they calculated person ears the number of people that developed carpal tunnel confidence interval. And basically what they showed is they had this odds ratio of developing carpal tunnel. I know this is a lot of little text, So what you can see here is down at the bottom when the odds ratio goes way up. So we're talking 1.4 to 2.2. You really are starting to see the people that are doing manual labor, right? So you see craft workers, fisher workers, home based personal care, health care assistance, childcare workers, cleaners and elementary occupations, which I couldn't really define what that waas Um But you can see that most of it is people that are doing manual labor. So is carpal tunnel related thio computer exposure, because I think that certainly in San Francisco, that's probably what we're seeing the jump in. It's not in the manual labor. So much of the people that are working from home on their computer. And certainly that's what showing a bump in my clinic, Um, and so there's not great data out there to say this, as I mentioned before, and what I found is too many analysis, and one was really a meta meta analysis. It was a review of one of the studies. So this study here was six studies, and it basically just showed that the results of contradictory s so that you can see that the risk for computer uses 1.67 and keyboarding 1.1 and mouse is 1.4. So they didn't really show that there's an association, but particular work circumstances can be associated with carpal tunnel. So again, that's not that helpful. And then in Journal of Neuroscience in 2015, this is really the meta meta because they reviewed two prior meta analyses, one of which showed no correlation, which is a prior study, and one should a positive association with computer or typewriter use mouse use frequent computer use. And then these are the numbers of the odds ratio goes up so frequent mouse use within the year, Um, so it's hard to say you have one study that does in one study that doesn't so you know, what can we say? Well, we know that medical causation, definitions and consensus air lacking right. But once that when the medical causation is lacking, then you really look to the legal definition to say what is the standard of care here? And unfortunately, this varies from state to state. So really, what the clinician's role is to record the details of the circumstances that surround the injury or illness, right? So that means documenting what the patient states that they're doing. So maybe they say they're working from home. I haven't had unorganized Mick assessment. This is what I've been doing, you know? And then you want to document kind of how many hours or typing what, what what they're doing. What they're set up is like a home Onda, then the insurance adjustor. It's their job to use this information to determine work related nous and eligibility for workers comp. Right? So really, what we as physicians have to dio eyes to just document what we find possible. So when people come to my clinic and I'm talking to them about work, I certainly make sure I know how much they're typing every day. What they're set up his home. Have they had an ergonomic assessment yet? So attributing occupational exposure to an illness like Eurotunnel is challenging, Um, but because the evidence is weak out there, right, so it's our job to document as much as we can. When you look at California, carpal tunnel is the most common work claim. That's associate ID in California, so have any occupational injury. Is work related if it's a result of an event or an exposure to, uh, at your workplace? So carpal tunnel is considered a cumulative trauma, right? So most people don't come in saying I developed carpal tunnel on February 7th of 2000 and 19. Most people will say, I don't know. My hands started feeling them in the past few months, so California Workers Comp defines cumulative trauma is an injury resulting from repetitive mental or physical traumatic activities over an extended period of time? Eso that's actually part of labor code 5412 which is for cumulative trauma right there. There's another labor code that says, like it happened on this specific date, but for carpal tunnel. They're going by labor code 5412 So, finally, how could we help? Right. We know. We know the data is sort of inconclusive at best. Um, it's really to talk to the patient about ergonomics, right? So what we know is this is the ideal typing position. Hopefully, most people have a more svelte looking computer than the one in this picture here. But the things that we're going to go over the position of the chair, the position of your neck, the position of the computer relative to your eye level in the position of your feet on the floor. So things that help when we talk about keyboards, our light touch keys, neutral or negative tilts. So meaning having the computers that the keyboard tilted slightly forward and below you the wrist in a neutral position So you don't want the wrist Flagstar extended. You want it to be in neutral on as much of the time is you have it keyboard without a number pad. Um, so basically, it's just saying that the number pad on the side, when you have to, like, reach all the way over to the side is getting the wrist out into a flexed position to do it, so that's like having the numbers on top versus on the side. Um, And then there's kind of the evidence on tenting or a split keyboard that could help keep the wrist in a more neutral position and then the Palm rest, which are the gel pads that you may see on a lot of computers. So there was a lovely article on this in the New York Times Online, which I put down here, and he couldn't reference this, which actually goes over all the ergonomic keyboard and has some recommendations. I just thought it was a nice reference point. So when you're talking to your patients about ergonomics and these are questions that I typically try to ask, so you want to know, are your feet resting flat on the floor? Right? Are your knees bent to about 90 degrees? And are your hip spent 2 90 degrees? Because your chair offer support to allow you to sit upright with a small curve in your lower back? Are your elbows bent to 90 degrees with your shoulders relaxed while using a mouse or keyboard and your eyes, Local level at your computer monitor. Now, most of the time guarantee that I don't ask these questions. But these air questions that you can include in your after visit summary to the patient to say, you know, you should get an ergonomic evaluation, and if your job doesn't offer it, there are several resource is that we can provide. You t get a better assessment of Are you doing it right when you're home and these are questions that you could consider. So if they say no, my feet are on the ground. When I have my knees and 90 degrees, you can put a box or a book under your feet. Um, you could elevate your monitor so you really want your monitor to be just below your eye level so you're not creating up or down to look at the screen. And oftentimes that means putting it up on some books. Um, you can use a towel like a rolled up towel for your lower back support, which actually helps arch your back to the normal, um, to the normal position. If you've lifted your laptop off up or if your mouse's up higher, you can use a Bluetooth keyboard or mouse that might help so that you're not reaching up like this. Also, using a tell or pad under your form to flow your elbow. Eso the keyboard should be slightly below your elbow. So if you remember from that picture, I should before elbow at 90 degrees. You want it slightly below that with arrested neutral. Um, the reference that I have here. There's a nice video through the American Society of Hand Therapy that goes over kind of all of these techniques that you should consider. Um, and they also recommend setting a timer to remind you to move at least every hour. So, basically, you should sit stand stretch. So this is every hour. You should be basically doing work for 28 minutes and then stretching for two minutes and it goes between sitting and standing. You don't want to be standing all the time. You don't wanna be sitting all the time. You do something in between and then think about the desk in terms of ergonomics. Um, so you have your primary work zone, which is the distance from the elbow to your hand. Um, secondary work zonas things in arms reach and then things that you don't need that you actually have to force yourself to get up and go get. And that's considered part of stretching. So ergonomics and keyboard again, it's inconclusive data, Um, but there's really only two studies out there. There was a nice study that was done in the Cornell Ergonomics Lab. Now it was using the Honeywell keyboard, so I can't tell you whether it was like sponsored by this. But what they did is they looked at office workers and had the risk position recorded. Andre had 23. Workers were using traditional keyboards on Ben. They transition them to use a preset, tilt down keyboard, and then they just had a control group. And so what they showed is with that tilt down keyboard hands moved within the neutral zone 67% of the time versus 42% of their keyboard arrangements, and that the pressure in the carpal tunnel remained below critical threshold majority of the time. So 82% in the tilt down andan. The seating posture was much better in that group, and then they reported, um, less musculoskeletal discomfort. So other non operative treatments so um this slide is out of place, so excuse me for that one, but splint ing So there is strong evidence to the support the use of immobilization for carpal tunnel. So in early carpal tunnel, I will suggest the people wear splints at night. So every night when they sleep, it keeps the risk in a neutral position, not flexed or extended nerve gliding exercises. So some people will send people to therapy to get nerve gliding exercises. And there's very limited evidence out there to show the effectiveness of this eso. It's really there's no difference. Anorthosis versus orthe ASUs and their gliding exercises in the study that was just in journal pan therapy. Um, so, typically, an early diagnosis Carpal tunnel. I'm not sending my patients to hand therapy because I don't think they're gliding. Helps, um, steroid injections. So while a carpal tunnel injection does help, most of patients have return of symptoms within a year on DSO. Oftentimes, I reserve carpal tunnel injections in the setting of pregnancy. I will certainly give them because it's usually related to fluid shifts that resolve after the first three months of postpartum, or if somebody has a diagnosis that I'm unclear of. So if they don't have classic carpal tunnel, um, if they have maybe a double crush and I want to see how much relief that they will get from a carpal tunnel release. Um, people don't have a nerve that's irritated anymore. Like if they have severe atrophy, the nerve might not just be working anymore. So going in to do a carpal tunnel release won't really help them. I will give them an injection to see how much relief that they get. Oral steroids. So the clinical practice guidelines have moderate evidence that support oral steroids. So there was two studies done one in 98 1 in 2011, which looked a different regimens, um, and review the data that you do have some improvement with use of oral steroids. But of course, there's a lot of other complications related to oral steroids, so I frequently don't give that aan den, of course, their surgery. So when carpal tunnel, what we're doing here is your coming through. Um, the Palmer fashion. So cut through skin palmer fashion down to the transverse carpal tunnel ligament. Here. This is the Palmer Spread. This you're in between the stars and high protein ours, and then you're looking to cut the carpal tunnel. So this is basically what we do, what I do. A mini open incision. It's about a centimeter and a half to two centimeters in length, and you're releasing the transfers Carpal ligament, which you could see in the practice image here. And this is thes air, just landmarks that I used to show how I define where my carpal tunnel is. So remember the carpal tunnel is here where the Palm meets the out form. I just use my landmark. So this is a piece of forum. Here's the hook of the hamate that's Palmer's longest, and that's how I find my landmark for the surgery. So, um, non operative management. So for cubicle tunnel, non operative management usually is night splints with elbow flexed at 30 degrees. So there was a study done that shows that if you splint people in about 30 to 45 degrees of flexion, people that have minor, uh mild to moderate symptoms for Cuba tunnel and used a splint for three months have resolution of their symptoms up to 82% of the time. So in early cubicle tunnel, I always recommend night splitting you. Can you use a reverse elbow pad or a hell bo pad so that you're not flexing your elbow? Sometimes I tell my patients to use, um, a washcloth that's folded up in a strap when they go to bed at night. So then I operative management really comes down to Do we just do a decompression, or do we do a decompression and transposition and studies in in 2000 and eight looked at a bunch of studies related to this, and there was no difference. But there was a 10 towards improved clinical outcome with transposition as opposed to decompression. So the it's a much bigger incision for transposition. A decompression is a smaller incision on. They usually return to function a little bit sooner, So if you do a transposition, this is just a example to show you here. This is a transfer. Here's the ulnar nerve. I've moved it from behind the elbow, which is in the bottom of the screen here. This is a factual sling that I've created to move the nerve anteria Lee, and then I take it through a flexion extension as you see here to make sure that the nerve slides and isn't getting pinched by Oh, my sling. So I think we did well. And hopefully I answered your all your questions that you ever needed to know about ergonomics as it relates Thio carpal on cable tunnel.