Dr. Heather Williamson is a 2000 graduate of KCOM and is board certified in family medicine and disaster medicine. She also has a CAQ in occupational medicine. She currently practices in the urgent care and occupational health settings with Mercy Hospital in St. Louis, Missouri. And as Jeffrey said, Heather is virtual, but she will answer questions. Heather, it's all you. Hello again, everyone. This is Heather Williamson back to talk to you about ergonomics. Learning objectives today are to be able to define ergonomics and work-related musculoskeletal disorders, define the elements of an ergonomic process, define risk factors for ergonomic-related injuries, understand the most common ergonomic-related work injuries, understand intervention strategies, and the basics of addressing causality for ergonomic-related injuries. So we have our resident expert in all things work safety, which is Homer Simpson. He says ergonomics helps to adapt jobs to the people who perform them. And I think that's pretty accurate. If you want the full-on definition, it's an applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely. OSHA's General Duty Clause, this might be important for all of you to remember. It says employers shall furnish to each of his employees employment and a place of employment which are free from recognized hazards and that are causing or likely to cause death or serious physical harm to his employees. One could argue that serious physical harm is not generally considered a consequence of poor ergonomic setup, but OSHA says otherwise. OSHA will cite for ergonomic hazards under the General Duty Clause or issue ergonomic hazard letters where appropriate as part of its overall enforcement. So they do take this seriously. So when assisting companies with designing ergonomics process and policy for their workplace, you have to have management and leadership support. If they are not on board, it's going nowhere. So management and leadership sometimes also have to be trained or educated by you as far as proper ergonomic processes and why ergonomics are important for their employees. You have to have employee involvement in this. They have to be willing to buy into the ergonomics plan and support it and implement it at the worker level. Everybody involved, management and employees need appropriate training. You have to have a hazard identification process, which is a lot of times where we come in for that, although it can also be done by people at the work site. Implementing solutions, we can also have good input into that process and evaluating the impact. Some people have heard of the plan, do, check, act process, which basically means you plan an intervention, you do it, you check to see if it's been helpful or has had no effect or a detrimental effect, and then you act on those results to change or maintain the policy. So when looking to identify hazards, you can analyze existing data like OSHA logs, first aid logs, work comp claims, incidents or near miss reports, insurance claim reports, employee interviews and surveys. But honestly, I think most of the time we see this when we have multiple patients that come in from the same employer with the same or similar diagnoses. There's also some variety of ergonomics checklists out there. They assist in helping to identify relevant risk factors, hopefully before injuries occur. NIOSH has a variety to choose from, a lot are industry or job tasks specific, but they also have a very general one, which we'll go over in a minute. NIH also has one specific to computer use. This is the NIOSH sort of more general hazard identification checklist. It includes things like performing tasks that are externally paced, and what that means is like a conveyor belt going through at a consistent pace, whether the worker is ready for the next unit to come by or not, exerting force with their hands like gripping, pulling, pinching, using hand tools or objects in their hands, handling parts, standing continuously for more than 30 minutes, sitting for more than 30 minutes without an opportunity to stand up and move around, use of electronic input devices like keyboards, mice, joysticks, trackballs for continuous periods of time more than 30 minutes, kneeling, activities with hands or arms above the shoulder height, a lot of bending or twisting at the waist. Vibration is also a significant hazard. Lifting, lowering objects between the floor and waist height or above shoulder height, lifting, lowering objects more than once per minute for a continuous period of more than 15 minutes, lift, lower, carry large objects or objects that cannot be held close to the body, and we'll talk more later about why that's important, and then lift, lower, carry objects weighing more than 50 pounds. So it's kind of a lot of things that you'd expect, but it's nice to have them all listed there. In general, they fall into several categories. There's risk factors, force, the amount of physical effort required to perform a task or maintain control of a piece of equipment or tool, the frequency, how many times an hour or a minute are they perform or a day are they performing the same task, posture, are they required to stand in like awkward or static postures like people leaning over to get objects or reach areas where they have to work. Vibration can affect a hand, arm, and the whole body. Worker-specific risk factors like pre-existing conditions, prior injuries, upper, lower body strength, smoking, and I probably should include here kind of a mismatch between the stature and the workspace. So if you have an employee that is relatively short, then the countertops or workspace may be too high up for them. If you have somebody who's very tall, then it may be too low for them. Examples of like awkward or static postures include working above chest shoulder height, kneeling, squatting, leaning or frequent forward bending, a lot of rotation of the torso, especially while lifting. The backs are not well designed for that, especially the iliolumbar ligaments. Forceful grasping of hand tools, tools held in a non-neutral or fixed position. Pinch grip, which means basically they're driving all of the power for using a particular item through the pinch between their thumb and index finger rather than the entire hand. Work performed with elbows consistently held away from the torso. So even if it's not above shoulder height, if they're doing a lot of things with their arms extended out in front of them or to the side, that engages the rhomboids and levator scapulae muscles in the upper back and they can see a lot of upper back strain from that. Any localized pressure on a body part, like where people are leaning up against a machine or an item as part of being able to accomplish their work duties. And also cold working environments. While cold itself is more of a physical hazard and not an ergonomic one, it does seem to, ergonomic injuries seem more common in cold working environments. Maybe due to a decrease in blood circulation in response to the cold, but it does seem to compound other ergonomic factors. So when doing a job hazard analysis, if at all possible, try to observe the operation. If it can be videotaped, that's extra helpful because then you can count the number of repetitions per minute of a particular motion or job task. Try to discuss the work process with the operator. What bothers them when they do it? What do they see as problems with how things are done with that particular process? You can then ask yourself two questions. Would I do the job this way? Would I want a loved one doing this job, especially this way? And if the answer is no, then there's definite need to have some kind of intervention. You can consult an ergonomist or an industrial hygienist as needed for additional data and suggestions about how to have a better ergonomic setup for a particular work process. So, board certification in ergonomics, there are two certifying boards, the Board of Certification in Professional Ergonomics. They offer the Certified Professional Ergonomist and Associate Ergonomics Professional, sort of like the position in a mid-level there as an analogy. These do require an advanced degree like a master's in a related field like engineering or industrial psychology, PT, human factors and ergonomics. Oxford Research Institute also offers a Certified Industrial Ergonomist and Certified Associate Ergonomist. And we get into the certificates. These frequently require only like a one to two-day workshop or an equivalent set of online modules and passing the test, so much less rigorous, much less experience and education involved in getting these. There are multiple companies that offer these certificates. There's Worksite International, which has Certified Office Ergonomics Specialist, Certified Chair Assessment Specialist, and Certified Remote Ergonomics Specialist. Matheson's Ergonomic Evaluation Certification, they just have one, which is the Certified Ergonomic Evaluation Specialist. And then the back school offers three different levels of Certified Ergonomic Assessment Specialist and then two other companies, Occupro and Humanscale, offer the Certified Office Ergonomic Evaluator. This kind of just lists sort of the hierarchy of experience with the board certification being at the top. Industrial hygienists are trained to anticipate, recognize, evaluate, and recommend controls for environmental and physical hazards that can affect the health and well-being of workers. That includes evaluation of ergonomics. So they can be very helpful in assisting you with either return to work or identifying hazards before an injury occurs. Industrial hygienists are board certified. It used to be the American Board of Industrial Hygiene and now it's the Board for Global EHS Credentialing. They offer the Certified Industrial Hygienist and Certified Associate Industrial Hygienist, although I don't think they're making any new associates. I think they're just maintaining the certificates of those who already have them. Companies can also request an OSHA on-site consultation. These are free to small and medium-sized businesses. There's priority given to the higher risk industries and companies. They evaluate potential hazards, not limited just to ergonomic hazards. It can be anything and your existing program's policies. This is not punitive in any way, so you're not going to get in trouble for having an OSHA on-site consultation. There's no citations or penalties issued and nothing is reported to OSHA. The consultant just makes recommendations to the company. But there is an expectation that the company, as part of this process, will comply with those recommendations. These on-site consultations do have a track record of lowering injury and illness rates, which saves money, improves morale, and increases productivity. They may be able to qualify for an exemption from routine OSHA inspections. So here's the hierarchy of controls. This will get talked about in other lectures, I'm sure, as well. But this is what do you do once you've identified a hazard and the various ways of going about dealing with that. The most effective is elimination. So if you cannot use that particular chemical or not use that particular piece of equipment that's causing problems, that's going to eliminate the risk of that problem to the employees. But if that can't be done, the next most effective is substitution. Use a different machine, use a different chemical, use a different process to get to the same end result, preferably one that's safer than the existing. The next step is engineering controls. This isolates people from the hazard as much as possible. We'll talk more about that in a minute. And then administrative controls, which are basically things like policies and procedures and changing the way people work and having adequate training. And then the least effective is protecting the worker with personal protective equipment. Engineering controls. These are the most effective, but also usually the most costly. These can include changes such as installing diverging conveyors or diverters on assembly lines or conveyor belts as things go through so that the worker does not have to reach to get something that's automatically diverted towards them or it's pushed closer towards them. You can have hoist or mechanical lift devices, which make lifting and balancing heavier or awkward pieces of equipment much safer. You can reposition or modify existing equipment. You can use counterbalance tools. You can have adjustable height chairs or adjustable height work counters or work stations so that it better fits people's stature. You can choose better or different tools and make sure that the tools are properly maintained. If you have a tool that's not properly maintained, not working right, is missing a part or in some other way, it does have an increased risk of injury. Examples of some of the engineering controls. On the top left here, we have the sort of before and after for a hoist balancer. On the left, you see a worker picking up this heavy, awkward item. On the right, it's being suspended from a hoist and balanced well so that the worker can move it around with a minimum amount of effort and strain. On the bottom left, that's a tilter. Instead of bending over to get parts out of a big container, it can be both raised and tilted towards them so there's less bending involved. On the top right is a lift table. These are adjustable so that the workspace can be elevated to the right height for the worker. Alternately, you can use a raised platform. Other examples of engineering controls would be a folding truck step. This is to help get in and out of a truck cab or to the bed of a truck to unload or load or secure loads. They also have pullout bars which can be stowed into the side of the vehicle, which you see on the bottom left there. Those help get the worker up so they're not climbing on the tire or pulling or doing a whole lot of stuff with their arms over shoulder height. On the top right there, you have some bent handle tools and that provides a more ergonomic position for the hand and wrist during use. On the bottom right, there is a pinch grip, which this person is trying to use a screwdriver in a confined space and only able to really use the index finger and thumb for that. If you get them a longer handled screwdriver, they can use their whole hand which then spreads out the force to the whole hand and wrist. Administrative controls include things like rotation of job duties. You could have a worker do a particular job for two hours and then go do a different job using different muscle groups and different ergonomic setup for another couple hours and then rotate back or do even other jobs. Try to minimize the excessive overtime. Allow sufficient breaks. Consider using staff floaters, people that would come in and sub in for you while you take a 10-minute stretch and rest break. Make sure everyone from leadership to floor supervisor to employee is properly trained on the use of the equipment and understands the importance of adhering to the work practices and policies. Institute appropriate policies such as requiring heavy loads be lifted by at least two people like in a tandem lift and have a repercussion-free environment for reporting both injuries and process and equipment problems. It's better to announce prevention as a pound of cure for that. Other administrative controls, things like work hardening. There's not a lot of evidence for efficacy for this, but it makes some amount of common sense. Start employees at a slower pace. Start employees maybe at one hour at the particular job instead of four on the first day. Especially if it's a repetitive task or involves a lot of lifting or bending. Sometimes also warm-up exercises or stretching program before starting the shift can also be helpful. Personal protective equipment. There's not a ton of this for ergonomic-related injuries, but it can include things like knee, elbow, or shoulder pads to distribute pressure. Padding equipment to reduce direct contact with hard, sharp, or vibrating surfaces, especially if somebody leans up against a piece of equipment frequently. And warm gloves, which maintain good ability to grasp items when in cold environments. Repetitive strain injuries, also known as cumulative trauma disorders. These are painful musculoskeletal disorders caused by cumulative damage to muscles, tendons, ligaments, nerves, or joints from highly repetitive movements. And then the OSHA uses the term work-related musculoskeletal disorder. This disorder encompasses repetitive motion injuries and also single incident injuries like I fell or I lifted something heavy and felt pain. Includes injuries to nerves, tendons, muscles, joints, ligaments, and circulation. So prevention for some of these injuries, we're frequently asked to do pre-employment physicals to determine if someone is physically capable of doing the proposed job. That can help decrease the risk of work-home claims, but you've got to be very careful with these. And I'm sure Dr. Fowler will discuss this some more, but even when you know the worker is going into a job that poses a risk, especially from an ergonomic standpoint or repetitive nature standpoint, these can be tricky legally. You can't do pre-offer employment physicals, it has to be post-offer only. You can't exclude someone solely based on a history of a pre-existing condition or prior injury, aka a history of a disability. If you do fail someone on a pre-employment physical, you better make sure you thoroughly document why and make sure it's consistent with the ADA, the American with Disabilities Act requirements, and that no reasonable accommodations are available at the employer to allow the employee to perform that job. I mean, obviously you're not going to sign off on someone who is legally blind to fly a fighter jet, but at the same time, you've got to be careful on the people that are going to end up doing a lot of lifting that have a history of back surgery. Definitely get letters from prior physicians or clearance letters from their treating doctor, if at all possible, to help support your denial. Functional capacity evaluations. These are sometimes done separately from the pre-employment physicals, so sometimes we don't see the results of this. There are things that can be done in your office depending on what they're looking for. But these have to be done post-offer pre-placement, again, cannot be done pre-offer. They may be helpful in reducing future injury claims, and they can kind of help weed out those who don't even come close to the physical capacity to perform the job. Like if they can't lift that 40-pound crate of weights at all, then they're not going to be able to lift the 40-pound object at work. Sometimes these are used post-accident and return to work. There's a lot less data on their efficacy as far as keeping people at work or preventing additional injuries, and the data is kind of mixed on that. But sometimes they can be helpful when we're seeing somebody with an injury to help determine like their restrictions, their work capacity, and suggesting job modifications that will allow them to return to work. But again, they're not always something that we see prior to signing off on their work physical. So common ergonomic-related work injuries include lower back pains and strains, carpal tunnel syndrome, neck strains, shoulder and rotator cuff injuries, tendinitis, lateral epicondylitis, and trigger finger. Starting with lower back strains, about 26% of working adults experience at least one episode of lower back pain. At least 20% of these are diagnosis work-related, though honestly the percentage is likely much higher. A lot of people just go to their primary care doctor and don't tell work and don't even tell their primary care doctor that it's a work-related event. Six to 10% of workers with lower back pain stopped working, changed jobs, or had to make significant changes to their job duties due to their back pain. So some risk factors for lower back strains. Age. Certainly as you get older, your back is less resilient and you're going to have an increased risk of strains. If you have a physically demanding job with a lot of bending, lifting, twisting, surprisingly a lack of support from the supervisor and job satisfaction are actually playing into a lot to low back injury claims and also with whether or not somebody returns to their job after their back injury. Prior history of low back pain or strain. Full body vibration like riding in a truck or earth mover or leaning up against a piece of equipment that vibrates and also if the employee has a lack of knowledge or fails to implement the proper ergonomic practices like they just decide to ignore the recommendation to tandem lift something that weighs 80 pounds and they decide to do it by themselves. This kind of illustrates the relative force on the back, the pounds of compressive force on the lower back from doing different activities. So the average person standing upright is about 80 pounds. Standing upright carrying 20 pounds just slightly up against their torso but about 10 inches away from the lower back goes up to about 170. If they're lifting with their arms outstretched somewhat away from their center of mass, away from their torso, then the amount of force goes up significantly. Bending over and lifting especially away from the torso, having to reach out with the arms gets it up to 635 pounds of stress on the lower back. And then even just bending over and lifting one pound that's 20 inches away so stretching out reaching to lift is still an enormous amount more force than you think. And sitting leaning forward lifting one pound, mildly increased but not as bad. So as much as possible you try to get people to bring the load close to their torso and close to them when they're lifting. So our expert on ergonomics and all things work safety, Homer Simpson. So if you look here at how Smithers is pointing out the proper way to do things when you're lifting an item should squat lift with the legs and the knees, try to grasp it close to the body. The one over here with the red X is somebody just bending over not using their knees not squatting to lift and reaching out slightly farther away from the torso like Homer and you can see his backwards. And also it's important to make sure employees understand that if it's too heavy that they ask for help. A lot of employees feel like they can't do this for whatever reason but it is very important for their back that they get help with very heavy loads. So also try to keep the arms and elbows near the body that helps you bring the load close to your center of mass. When you change direction people should move their feet so I tell people that their feet should always be pointing in the same direction as the whatever they're carrying. So if they have to pick something up you know they squat pick it up close to the torso they lift they turn their entire body including their feet then they can squat and put the item down. Our blowbacks are not at all well designed for the combination of bending and twisting and I see an awful lot of ilial lumbar ligament strains from people bending and lifting at the same time. All right everybody's favorite repetitive motion injury carpal tunnel syndrome. So risk factors include repetitive and or forceful hand motion so a lot of gripping twisting that kind of thing repetitive flexion and extension of the wrist use of vibratory tools use of power tools many of whom also vibrate and questionable about the use of computer mice. Non-occupational risk factors include age diabetes pregnancy low thyroid acromegaly tenosynovitis in the wrist and rheumatoid arthritis. So if you just look at the the general adult population the prevalence of carpal tunnel is about one to three percent so a fair number of people will develop carpal tunnel who do not have any of these other occupational risk factors so the big question is how do you tease out which ones are work-related and which ones are just they drew the short straw fate and developed carpal tunnel. We'll talk more about carpal tunnel causality later but the neck and upper thoracic strains these are actually very common in office workers who are frequently stuck in a static posture it's usually not a very good posture a lot of times they'll be holding their head forward usually with their chin sticking out a bit like they're they're looking down or or even straight ahead sometimes to try to get their eyes closer to the monitor and they often have poor ergonomic setups of the workstation. I'm five foot seven but the average chair and table that you buy at like it's office depot does not really allow my forearms to get parallel to the floor when I sit and use the computer so you have to to do a few extra steps to try to get that to the right height. It's also common in construction workers, health care workers, manufacturing and then people like this guy who uses a crane and looks up all day long at his loads. Rotator cuff strains and tendonitis and impingement are also very common injuries but the problem is that the risk also goes up with diabetes age above 50 and and then repetitive and frequent use of the arms over the shoulder height it especially gets a little dicey to determine what's work related and what isn't when they have like a degenerative tear of the rotator cuff or shoulder impingement so sometimes you have to get some additional testing you know like MRI or consults with orthopedics about how much of this is work related certainly if they do a lot of overhead work like painters almost all end up with some sort of rotator cuff problems because they're constantly have their arms over their head. Then also people like this guy this truck driver climbing up into the truck you can see he's pulling himself up with that grab bar, and that puts a lot of strain. You know, they start at the ground level, reach up above shoulder height, and then forcefully pull themselves up into the cab. Not a great ergonomic setup. And then like this guy, who you can see he's got a pull-out bar to the left here to stand on, but here he's looking like he's going to stand on the tire and then reach up to get heavy items out of the side of his truck. Tendonitis. It's usually due to overuse of the body area, the tendons, and or overload of the tendons. So lifting something too heavy. A few of the common work associations with the shoulder. This includes things like biceps tendonitis, which would be a lot of heavier frequent lifting, a lot of over shoulder height or overhead height work, both for like biceps tendonitis and rotator cuff. Lateral epicondylitis is frequent with repeated flexion of the wrist with twisting, the supination pronation of the forearm, like using a screwdriver, pulling weeds, sometimes even carrying heavy briefcase for long periods because they have to constantly stabilize that. Medial epicondylitis can be with any sort of repetitive elbow. Dequere veins, which is along the radial aspect of the wrist, is implicated in repeated grasping or pinching with the thumb, which also sometimes happens with use of the computer mouse. So especially if they're moving the mouse around an awful lot and not just clicking, then that can predispose to dequere veins. Also repetitive thumb abduction and repetitive wrist motions. Patellar tendonitis, a.k.a. jumper's knee, can be with repeated forceful contractions of the quadriceps, especially when jumping and climbing, like the truck drivers we saw before climbing up into their truck were having to climb up into their load to stabilize it or load. Trigger finger, that can be associated with chronic inflammation of the finger flexor tendons in the palm. It's related to repetitive and forceful finger motions, repetitive or prolonged firm gripping, use of tools, especially vibratory tools because they can help build up scar tissue there in the palm. But there's also increased risk with arthritis, gout, diabetes, and age over 40. So when talking about computer use, because this is one of the big areas of ergonomics, in tendonitis, computer mouse uses, in addition to the possible associations with carpal tunnel, it's also been linked to tendonitis in the wrist, forearm, and shoulder, as well as sometimes medial and lateral epicondylitis. It's been dubbed mouse arm syndrome, mouse arm, mouse elbow, and mouse shoulder. I think it's really important if you get somebody with this to very carefully take a history, try to get photos of their workstation, figure out the positioning of their body while they're using their computer, because that can really, you know, you do that 10 hours a day, eight or 10 hours a day, it can put a lot of strain on various tendons. Evaluate the use of wrist rests for keyboard and especially for the mouse, because sometimes those will end up forcing the wrist out of a non-neutral position, even though they theoretically feel good when you first start using them. It can also end up putting excessive force onto the carpal tunnel in the wrist there, if they push down hard. So good working positions are more of a neutral body posture that's comfortable in which the joints are naturally aligned. We'll talk a little bit more about that in a bit. This reduces stress and strain on the muscles, tendons, and skeletal system, and reduces risk of musculoskeletal disorders. Ergonomic mice and ergonomic keyboards have not really been definitively shown. No single one's been definitively shown to be effective across the board, but if you have a particular worker, particular workstation, particular problem, it may be helpful. So it's something that you can recommend. I definitely recommend keyboard trays frequently. These are cheap and easy for the employer to get and install, and especially it has to have room for the mouse next to it so that people are not working with their arms extended out in front of them. And our expert, Homer Simpson. I know this looks silly, but this is actually all medically correct. I hand this out to a lot of my patients who have repetitive strain injuries from computer use, because it gets them to look at it a little more closely, because it's kind of funny, starring Homer. And if you look up here at the top, you know, Homer's looking relatively straight ahead. The top of the monitor should be, the top third of the monitor should be about where the eyes come onto the line of sight there. He's got a good chair with good lumbar support, allowing him to keep his back straight upright. His hips are flexed to 90 degrees and his knees are at 90 degrees. His feet are flat on the floor. If you have some people with a setup that can't get their feet flat on the floor and still have them at 90 degrees, then they can use a little footstool, and those are also easily available at Office Depot. Homer's shoulders are down and relaxed, his elbows are about 90 degrees, and his wrists are in fairly neutral posture, which is either straight out or slightly extended. And his, down here, you know, you can see all the things not to do. So he's got a cruddy chair, his feet are not flat on the floor, you know, hips and knees aren't at 90 degrees, especially the knees are over 90 degrees. He's got this flexed wrist posture, and he's all hunched over. He's trying to get himself closer to the screen. So even when you have a good ergonomic setup, like on the top left, there some people will still find themselves leaning in to see the screen better, and that's sometimes more out of habit than actual eyesight necessity. Also on the top left here, you note he has a keyboard tray there that he can use that brings the work closer to him, as opposed to having it up on the desk, which is too high for him. You also get a lot of people these days using laptops. Standard laptops, they really force you to trade off between having the screen at the right height and having the hands and wrists in the proper position. So if the screen is at the correct height, the keyboard then is too high up, forcing the wrists usually into flexion. If the keyboard is in the correct position for the hands and wrists, the screen is too low. So then they end up, you know, hunched over, their chin forward, rounded shoulders, not great for the neck and upper back. So a few solutions for this. It's difficult if they're on the road with the laptop all the time, but hopefully they're not using it constantly. But people that do use it more consistently, the recommendations are you can use an external monitor, you can use a separate keyboard and mouse. So basically you're separating out those functions so the monitor and the keyboard and mouse can be at the correct height. You can also use laptops that allow separation of the keyboard from the monitor so that both can be positioned ergonomically. And one other image of this for setup is this laptop solution here. It's a laptop riser, so it raises up the screen to a better height while the person also uses an external keyboard and mouse there. You can also see a very nice document holder there on the left, which is also helpful for preventing people from being hunched over and sticking their chin forward or looking down frequently. OSHA has a computer workstation checklist that can help create a safe and comfortable computer workstation. It has sections on posture, keyboards, mice, stuff like that, monitors, chairs, and the document holders. So check that out. I included the link there. So when assessing for a causation, it's important to understand and document the details of the job duties that may contribute to their symptoms. So find out exactly what they do, exactly how their body's positioned while they do it, how many hours a day do they do this particular task, and are the job duties biologically plausible as an explanation for their symptoms. I mean, I don't think necessarily that someone's foot pain is related to their sedentary job as working on computers. That's probably not related to that. When did their symptoms begin in relation to starting particular job duties? So did it start day one when they started working there? Was it present before they started working and it got worse? And you can have repetitive strain injuries and ergonomic related injuries that do not manifest until months to years into performing a particular job, but that temporal association is important. Do they have any pre-existing conditions or comorbidities? You know, if they're complaining of carpal tunnel-like symptoms, have they ever had that before? And what were the circumstances surrounding that? What types of activities seem to trigger their symptoms? Is it when they work on machine A but not on machine B? And are the symptoms present when they're on vacation or when they're off over the weekend or when they're assigned to different work duties? Are they still symptomatic? Things like if they take a week off and go to the beach, either their symptoms get a whole lot better or resolve and then come back on Monday morning when they're there. Are they better over the weekend and worse during the week? Those are important to know. Also, are symptoms always present when performing specific tasks? So is it every time that they use a screwdriver they have pain in their wrist or is it just occasionally? Other thing to note too would be what do they do outside of work? What are their hobbies, activities? What do they do over the weekends? You know, that can give you a lot of insight into other potential causes. You know, do they have a second job? Do they run a small business? That sort of thing. So in addition to taking a good history, I think it's important to try to get some other objective information. Talk with the employer. Is the report of the injury accurate? Is the report of what their work tasks are, is that accurate? How many hours a day are they working on a particular machine or a particular task? Have they had a job analysis performed by, you know, anybody at the plant or an industrial hygienist or an ergonomist? Is there a videotape of the process? Can you directly observe the operation? And are others in similar positions having similar problems? Like if you see a whole group of people with similar issues, then they probably have something going on that is work related. Like I had a group of people coming in with a lot of problems with their wrists and hands and upper back from who worked as dental technicians. They designed and fabricated dental appliances like crowns and partial plates and stuff like that. And their job involved them leaning over. Their countertop height was kind of high for where they were working. And so they had to get close to the objects. Eyes needed to be close to because they're working on relatively small items. You know, crowns are not huge. So they had to be close to it. High counters. They were leaning their forearms, bracing their forearms on the edge of the counter in order to stabilize everything so that they could both hold and then polish or grind on the dental appliance or paint it. And so all of that together, you know, they had them hunched over their chin sticking forward and pressure on their forearms. And then they were using repetitive, a lot of repetitive motions and vibratory tools. So that was kind of the perfect storm of ergonomics problems from the upper half of the body. Okay, so getting into the causal relationship between carpal tunnel syndrome and computer use. The literature is unclear to say the least. Some studies show a possible association between frequent mouse use, especially more than 20 hours per week, but not specifically with keyboard only use. Although these days, I'm not sure how many people only use the keyboard, not the mouse. Some small scale studies do show an increase in carpal tunnel pressures while clicking and dragging the mouse, because usually people will push down with their wrist there to stabilize while they move the mouse. And that may account for some of the link found with the mouse studies, but not all of them are consistent. A lot of these studies have potential for selection biases or just not very high powered because so few people in the studies developed carpal tunnel syndrome. And then you've got the general prevalence of carpal tunnel syndrome in the population being one to three percent, so it gets kind of difficult to really nail this down. Most important, I think, in a detailed history of how much mouse and computer keyboard use they perform. If they rest their wrist along the edge of the desk, in other words, have unusual amounts of pressure coming in right over the carpal tunnel, or if they have the wrist excessively flexed or extended, like if they're standing up way above the optimal height for their keyboard, then their wrists are going to be extended. If they're sitting and the countertop is too high, the desk is too high, then their wrists are going to be flexed. If they're using a wrist rest, because again a lot of people press down on those and that puts pressure on the carpal tunnel, especially while clicking and dragging, then if you can get photos or video of the employee at their workstation, it can help you to identify problems that can be contributing to external compression of the carpal tunnel and or the flexor tendonitis. But to summarize, when you're looking at carpal tunnel syndrome and computer use, it's good luck with that. I oftentimes will, if it's unclear, will defer to a hand specialist for the causality determination, especially with just straight computer use. It gets easier if they use a lot of vibratory tools or do a lot of repetitive hand or wrist motions, but the computer is the difficult one. So we also talk about pre-existing conditions when dealing with a lot of these repetitive injuries and some terminology that's important to understand when you're putting this in your notes. An exacerbation of a pre-existing condition is a temporary flare-up, like they have chronic neck pain, but their neck pain is worse in the last week, but you expect it to go back to baseline once this episode is over. And then you can have an aggravation, which is permanent worsening of the underlying condition, like they used to have neck pain that averaged a 2 out of 10 and long term now they're going to have neck pain that averages out to a 4 out of 10 or something like that. So it's important to be clear on that in your notes. Thank you everybody for listening. Yeah, this is Randy Peters out in Pittsburgh. That was a great presentation on ergonomics. Thank you so much. I have a really very, very broad general question about ergonomics. I'm relatively new. I've moved from primary care to being employee health, and I'm trying to figure out where the line is in terms of not establishing a physician-patient relationship. Like I really want to keep it to just prevention. And I'll give you a specific, you don't have to solve this specifically, but just to give an example, I've been seeing a large number of, we have a big huge number of ultrasound techs, and ultrasound technologists just get the weirdest cumulative strain injuries. Their hands are in weird places, their elbows are extended, their jobs are, they do a lot. And when I saw the sixth, when I said, okay, I need to figure out how to address this, but I sort of ran up into this line, like, you know, somebody who's really knowledgeable, personally sent them to for physical therapy, said, how about if I come into the workplace and look at what they're doing and give them advice? It seems, it gets a little weird for me. At what point am I crossing the line between trying to, I want to try to keep it preventive, but I'm not really sure where the line is between establishing, like, I'm actually caring for these people, trying to tell them how to do their jobs individually. And if there's like a real general beginner reference on this, you can just point me to it, but just in terms of general ergonomics, I keep running into that issue. The more I want to get involved, the harder it becomes to try to determine when I'm crossing the line from just being the company doctor to being a treating physician. Dr. Williams, you want to respond? Yes. I think a lot of that comes down to, it depends on your state's definition of when you define the physician-patient relationship, but that's usually when you've agreed to treat someone for their concern or problem. So like, when we do DOT physicals or pre-employment physicals, we are not creating a physician- patient relationship because they're not coming to us for treatment. We're not agreeing to treat them for anything. We're just doing an evaluation of them. And I think you can say the same for, if you're going into the workplace to look at a group of how a group of ultrasound technicians perform their duties, you're saying, I'm doing an evaluation. I'm not agreeing to treat Mary Smith for her purple tunnel syndrome because of these problems that she has with her ergonomics. So I think that's, that's the way you look at it. You have not agreed to treat this individual yet for their problems. You're just evaluating the workplace and making suggestions to them. Does that make sense? I think, let me make sure, if I said to radiology, hey, you know, we hear an employee, we're seeing a bunch of ultrasound tech, would it be okay if we came in and just like took an evaluation, did it, and then maybe gave you some general tips and ideas on, you know, some ergonomic techniques, that would be, that would be okay. But like, because, because on the other end, I'm treating these people for workers' comp injuries. But if I go in and like look at somebody specifically that I'm treating, that I'm evaluating for workers' comp, that's going to cross those. I have to keep it really general, like for the whole department, not for like some specific individual. Is my understanding that right? Right. I think if you're trying to have it not to be a physician-patient relationship, I think you're, you're trying to make recommendations across everyone who's an ultrasound tech at that facility. But, you know, in rare instances, you may say, okay, well, we have one ultrasound tech and I want to see how she's doing things so that I can make recommendations specific to her. But you're already have established a physician-patient relationship with her. That's one thing. But, you know, if you're going in and saying, I'm going to watch three different ultrasound techs perform their job duties, then it's not physician-patient relationship. That's, that's really helpful. Thank you so much. You're welcome.

ergonomics

workplace safety

musculoskeletal disorders

risk factors

ergonomic process

hazard identification

engineering controls

carpal tunnel syndrome