ergonomics | ergovet

Stretches and Strength Exercises for Surgeons

Recently, I’ve been catching up on some journal reading and came across an ergonomics article in an online plastic surgery journal that I wanted to share.

We feel your pain

The article, Stretching and Strength Training to Improve Postural Ergonomics and Endurance in the Operating Room, offers all the usual warnings about musculoskeletal discomfort among surgeons as a result of surgical postures. It seems that the areas of pain are similar to those in spay neuter veterinarians. Many of the surgeon postures described in the article are also common in veterinary surgeons. And many of the solutions they suggest, like adjusting the table height or sitting for surgery, are the same as we have discussed previously.

Painful body areas in the study of surgeons. Look familiar? Neck, back, and shoulders are common areas for spay neuter vets to experience pain as well.

Stretches for Surgeons

What I liked about the article, though, was that it published a supplemental set of videos of one of the authors’ consultations with a physical therapist. The physical therapist offers exercises and stretches to counteract common surgical postures. The videos are available along with the article (and are slow to load, but be patient). Video 1, video 2, and video 3 are all recordings of this consultation, while the final video shows the surgeon by himself, performing each of the exercises from the consultation in the first 3 videos. The final video goes too fast for viewers to follow along while doing the exercises themselves so works better as a reference than as an accompaniment to exercise.

These videos offer something specific that I hadn’t seen before and that I have wished I could share with others: stretches and exercises targeted for surgeons. (Maybe this exists somewhere but I haven’t come across it yet). I’m curious to try some and if they help relieve some neck/shoulder/upper back tension.

It would be even more exciting if the study had actually tested the stretches and exercises to determine if the surgeons were more comfortable or more flexible after using them for a time. But they didn’t, so as it is we’re left with recommendations based off the physical therapists’ “standard practice algorithms” for addressing the surgeons’ complaints.

Limitations

The study had other limitations besides not having tested the exercises on surgeons. The study design isn’t optimal: the sample size is limited, and the authors didn’t use a validated musculoskeletal discomfort questionnaire. The participants’ surgical posture self-assessment was also problematic. After watching a 2-minute video, the participants were asked to judge deficiencies in their own surgical posture based on their ability to complete the stretches and range of motion activities in the video. They didn’t have the chance to view video of themselves at work or to have any assessment by an ergonomist or physical therapist, so I’m skeptical of that measure’s validity.

Despite the article’s shortcomings as a scientific study, I think that the exercises suggested in the videos could be a good resource or starting point for surgeons experiencing discomfort and for those trying to avoid it. Let me know if any of these work for you, or if there are any other exercises or stretches that work better.

Meanwhile

Today we had the chance to fire up the Hartland Community Oven which was built in our town during the pandemic. Tina was on the oven committee (she helped build it, too) so she has been through several firings in 2020 and 2021, but this is only my second time baking in the oven. Despite a sometimes windy, sleety afternoon, we spent a few hours out there baking different things as the oven went from really hot to only sort of hot. Everything looks and tastes great and I think I’m done cooking for the week! (well, maybe).

Lifting and Carrying a Large Dog

The need to lift dogs is common in small animal clinics. What are some ways that we can make lifting easier and less challenging on our bodies?

In the previous post we talked about some basic principles of lifting and carrying. Today we’ll expand on those ideas look at lifting large dogs.

Workers restrain a standing dog. This restraint posture (one leg kneeling and the other bent) could also be used to lift this dog.

The need to lift dogs is common in any small animal clinic, especially in HQHVSN. The dogs we lift may be awake, sedated, or fully anesthetized, and each type of lift comes with its own challenge. Awake dogs may resist handling and wiggle, while anesthetized or heavily sedated dogs may be loose and floppy and difficult to grip.

What are some ways that we can make lifting easier and less challenging on our bodies?

Standing or Lying Down?

Remember that the height of the lift is a factor in the lift’s difficulty. It’s easier (ergonomically) to lift a standing dog than one who is lying down. (It may not be easier overall if the dog wiggles or resists). The standing dog’s center of mass is higher than the ground and already closer to the lifted position. This means you don’t have to lift that center of mass all the way from the floor to your waist height or to a table.

Lifting a standing dog requires less bending and less muscle effort than lifting a dog who is lying down.

Back, Hips, or Knees?

When lifting from the floor, workers may bend at the knees, hips, or back, or a combination of all three. Generally, we are told to “lift with your legs not your back.” And to some extent this is true: repeated, extreme flexion of the back puts much of the strain of the lift on the vertebral joint end plates. End plate damage may be one of the causes of chronic low back pain.

In the first picture, workers bend at the knees and hips to lift an anesthetized dog from the floor. In the second picture, workers bend at the hips with a slight knee bend and lumbar flexion.

However, the recommendation to avoid any lumbar flexion during lifting is not supported by research. It’s definitely best to avoid extreme lumbar flexion (60^o or more), but it is OK to flex the back along with the hips and knees when lifting.

Lifting only with the legs has its down sides as well. People with painful knees or hips may be uncomfortable in the deep squat often portrayed in “proper lifting” diagrams. And bending and lifting at work can make certain workers more prone to knee or hip arthritis.

In the end, the best means of lifting probably involves moderate flexion of the knees, hips, and lower back. The “best” way to lift will vary depending on the specific task and the individual’s strength and pre-existing pain.

Not so good: Here the worker in magenta scrubs is bending mostly with her back rather than with her hips or knees. This lift will put unnecessary strain on her lower back. Also her hold on the dog’s stifle (knee) will not lead to a secure hold once the dog’s feet are off the ground.

Two Person Lifting

The workers are facing the same direction and will coordinate their movements through the clinic.

When lifting as a team, both team members must communicate clearly with each other. Both team members need to know where to position themselves, when to begin lifting, and where to carry the dog. For example, if a dog is to be lifted onto a table, it is important that both lifters know which way the dog should be facing on the table before they position themselves for the lift.

Use simple technology to help

Use technology for your lift! If you need to move a large sedated dog who can’t walk, consider using a stretcher or cart.

Our worker in the previous post used technology (a hand truck) to help transport a cardboard box. Likewise, we can use technology to help move our anesthetized dog. Stretchers and wheeled carts are both useful ways to turn a floppy, hard-to-grip load into a rigid load with handles.

Similarly, lowering a hydraulic table decreases the height of the lift, thereby decreasing its difficulty.

Lifting a dog from the floor to a table is hard, but lowering the table turns a 3 foot lift into an 8 inch lift and requires less effort.

Meanwhile…

I hope you all are staying safe and well. Here, spay neuter clinics go on even as we find ourselves dodging COVID and mud season simultaneously, just as we have the past two years. I feel lucky for the flexibility and adaptability of my vet techs and clinic hosts as we still manage to get those cats spayed before kitten season hits. Thanks y’all!

Lifting and Carrying

Let’s start with some ergonomics fundamentals: lifting and carrying. This post shares some basic concepts that we’ll be able to apply later to specific veterinary activities like lifting and carrying dogs.

This will be the first in a series of posts about ergonomics in the veterinary clinic–and everywhere else. It’s been a long pandemic, but in the past half-year I’ve had a couple of opportunities to talk about veterinary tasks aside from surgery. Today’s slushy snowstorm seems like a good time to share some of the illustrations and ideas from these presentations.

March “snowstorm” with Spaymobile in background

Lifting and Carrying: the fundamentals

First, what are the characteristics of a lifting task that can make it more or less hazardous?

Weight of load
Distance of your hands from your lower back
Height of lift (From floor or from above knee height? How high do you need to lift?)
Twisting and side bending
Working in a restricted space
Good grip, or irregular, bulky, floppy, unpredictable load
Flooring condition (dry, clean, good condition, or wet or uneven)
Communication and coordination when lifting as a team

Carrying an object close to the body and near waist height

For our lifting and carrying example, we’ll use the ubiquitous brown cardboard box. In the first illustration, the lifter is carrying a box near her body and near waist height. This puts the object close to her center of mass and puts the least amount of strain on her body. It makes intuitive sense to us that she would carry the box this way instead of carrying it with her arms extended, far away from her body and her center of mass.

In this next set of illustrations, it looks a bit strange to carry the box with extended arms. But when the worker is carrying a larger box of the same weight, she is essentially doing just that– carrying the weight further from her center of mass and putting more strain on her back. A bulky object’s center of mass is further from the worker’s center of mass, meaning that even if this object is the same weight as the first box, it puts more strain on the worker’s back. The increased strain is due to the leverage created by the weight’s greater distance from the worker’s core.

While carrying a box far from the body looks strange, it’s the same strain as carrying a big box of the same weight.

(Want to learn more about how lifting strain increases depending on the size, shape, and weight of the object and the height of the lift? Check out the NIOSH Lifting Equation.)

Another circumstance where the worker might be holding an object far from her center of mass is when obstructions in the environment require her to do so. Removing objects that obstruct work areas (such as boxes obstructing a countertop) may seem obvious but it can also be the “low hanging fruit” when making ergonomic improvements.

In the first illustration, the worker has to extend her arms to place the object on the counter. In the second, the obstructions are removed and she can place the object without extending her arms as far.

Yet another reason for carrying a weight far from one’s body because it the load is smelly, damp, messy, or covered in some bodily fluid– but the same principles apply. If it’s a soiled but lightweight cat carrier, it makes sense to hold it at arm’s length on the way to the wash area. But if it’s a whole load of smelly laundry or a patient covered in pee, using a protective barrier (plastic bag or clean towel) and holding the weight close to the body is a better choice because it allows for a more secure hold and less strain on the lower back.

Lifting below the knees or above the shoulders adds additional strain.

Lifting or placing objects below the knees or above the shoulders also adds additional strain on the worker’s body. Low placement may put strain on knees and lower back, while high placement can strain shoulders and arms (and introduce the risk of the object falling). Heavy items that need to be lifted and carried (cases of wet food; trays of instrument packs) should be near waist level to reduce the strain of lifting them. Lightweight objects can be placed on high shelves, with the bottom shelves reserved for heavier objects that will be transported with mechanical help like a wheeled cart or items that are used less often.

A worker uses a hand truck/ a dolly/ a trolley/ a two-wheeled cart to transport a large box. (Nomenclature for this device varies a lot as you can hear in this link )

Mechanical help can be an excellent way to reduce strain when transporting objects. Gurneys, hand trucks, carts, and other devices bear the weight of the load, freeing the worker from the heavy lift.

Next time we’ll talk about the ergonomics of lifting and carrying dogs– stay tuned!

Surgical Ergonomics: Movement and Posture

In order to find pictures to demonstrate surgical posture, I went again to Google images to find some pictures of spaying and neutering, and came across several with surgeons in what appeared to be uncomfortable and ergonomically risky postures. Here are a couple of photos that I found:

https://images.app.goo.gl/7Fhew62NGyxoGRe96

https://images.app.goo.gl/QmP7Mmq6uqSUKyGh7

Both of these pictures show trainee surgeons leaning over their patients with about a 90 degree neck angle, bent waists, and elevated shoulders. We can’t know if these surgeons are using their bodies in this way because of the way their surgery room is set up, or because of habit, apprehension, or unawareness of their posture– or all of the above. Maybe these are brief positions during the surgery – but if these postures are sustained through a surgery day, these individuals are likely to experience some pain as a result.

In small animal surgery, we can achieve a fairly neutral posture except for our neck position. A neutral neck position would involve flexion of less than 10 degrees, but for a surgeon it is often 20-30 degrees. In this picture, I have a neck angle approaching 40 degrees.

It may not be possible to avoid extreme neck flexion in this work, and the important thing will be getting out of this posture between surgeries to allow those muscles to release and stretch. Turning your neck to each side, rolling your head, extending your neck, and shrugging your shoulders are all ways to release the tension in the muscles around your neck.

Other surgical postures to watch out for can be twisted or asymmetrical postures. If a surgeon maintains an asymmetrical or twisted posture, that can lead to uneven muscle use and strain and discomfort at the end of the day.

However, varying position during the surgery day is a good thing. If this surgeon balances the twist in one direction over time with a twist in the other direction, then she may not experience strain from the posture.

In this case, this surgeon might be more comfortable with a foot stool to rest her foot on, rather than using her weight-bearing foot as a footrest.

Another important thing you can do for yourself is to move during the surgery day. Between surgeries, take a few seconds to change your position. Roll your neck and shoulders, stretch. walk a few steps.

A study on human surgeons (abstract here) showed that taking a 20 second break every 20 minutes can increase your comfort and decrease fatigue after a day of surgery, and it can sustain your surgical performance and accuracy better through the surgery day. (If you can get access to the article, it’s a fun read not just for the scientific finding but also for the authors’ wry humor).

We are fortunate in spay neuter that we have short-enough surgery times that we can use the end of each surgery as a cue to move a little. We aren’t doing hours-long surgeries where we would need to set an alarm to remind us to move (although if you are someone who does long-duration surgeries, setting an alarm could be a good way to remind yourself to take your 20-second stretch break). So take a moment when you switch from one surgery to the next, to break the muscular tension that you hold during surgery.

We don’t necessarily think of or talk about spay neuter surgery as a sport or an activity that requires physical fitness or work hardening, but it does. As you do this work, your ligaments adapt, if you give them the recovery time they need between use.

Ligaments adapt to exercise and use by increasing size, strength, and collagen content (given adequate rest and recovery time between uses)
Surgeons in regular work may have greater resilience due to this tissue adaptation
New HQHVSN surgeons (or those returning from an extended break such as a maternity leave) will not have the ligament strength and may be at greater risk for hand/ wrist injury and discomfort.
Consider having a lighter schedule for new/ returning surgeons to allow their bodies to become conditioned to the work. Gradual increases in work hours, rather than starting off with a full-time schedule, may be more likely to lead to well-adapted ligaments rather than injury and strain.

For a much more in-depth discussion of ligament physiology, check out Ligaments: A source of musculoskeletal disorders. If this link isn’t available (it is not from the original publisher’s site), you can find other versions posted on Google Scholar.

Solomonow M. Ligaments: a source of musculoskeletal disorders. Journal of bodywork and movement therapies 2009;13:136-154.

Finally, physical activity outside of work is important to reducing physical discomfort while at work.

Physical activity outside of work is known to be associated with lower prevalence of pain
Surgeons who are physically active experience less fatigue due to work
For people experiencing low back pain, maintaining daily activities as much as possible is associated with quicker recovery from symptoms
Staying physically fit, maintaining friendships outside of work, eating well, and maintaining a work-life balance are all ways to reduce work-related musculoskeletal discomfort and stress.

There are not specific activities or exercises that research says are “best” – and it will likely vary between individuals– the key is simply being active and moving.

I hope this series of posts about surgical ergonomics has given you some ideas of how you might improve your own comfort during surgery. Remember that taking videos or photos of yourself during surgery can be a great way to understand what you are doing with your body, and to start to make improvements.

Let me know what works and what doesn’t work for you, and make comments with questions and with your own experiences of surgical ergonomics.

Surgical Ergonomics: setting up the physical space

In this post, I will share some ideas about how to set up the physical space in surgery.

I want to start by encouraging you to take photos or video in order to evaluate your surgical ergonomics and body posture. It’s hard to pay attention to your body posture while you’re in the middle of surgery. Even if you are trying to pay attention to postures and positions, you may not be able to know or evaluate your posture without a view from the outside. By taking video, you can later watch yourself and find problems that you can then make a special point of changing during your next surgery. The technology is so accessible now– a smartphone or digital camera is all you need. You can prop a phone on a box of gloves; tape it to an IV pole, tape it to a surgical light, or use a tripod.

In the picture here, I had set up video of myself from above and behind because I was having shoulder and upper back pain after surgery days, and this helped me figure out when I was tensing up so I could work on that.

dog neuter screenshot

The physical environment includes things like the height of your surgery table and how you position the patient and objects in your space. These factors influence the way you use your body– and changing them doesn’t have to be difficult or expensive.

In this first example, the surgery table is too high, so the surgeon has to raise her shoulders and abduct or raise her elbows in order to reach the patient. This puts strain on the upper body, especially the neck and shoulders.

table too high

In the second picture, the surgery table is too low, so the surgeon has to lean forward in order to reach the patient. This could place strain on the neck, upper back, and lower back, and perhaps also the shoulders.

table too low

When the surgery table is adjusted comfortably, the surgeon can stand with a relaxed upper body and arm posture.

table correct height

In general, the easiest table height for a relaxed posture is one in which the hands fall about 5-10 centimeters – or 2-4 inches– below the elbows. This means that the table height will need to be adjusted between large, deep-bodied dogs and small patients, in order to keep the surgeon’s upper body in this relaxed position.

Not everyone has access to tables that adjust adequately, but this doesn’t have to mean that you are condemned to upper body strain. Low tech solutions like step stools or platforms, bed risers, blocks, and other boosters can help get you and your patient to a comfortable height.

Another positioning issue that comes up sometimes is that a tiny patient is placed in the middle of a surgery table, so that the surgeon has to reach a long way to the patient, or bend forward. A lot of reaching and bending can put strain on the upper and lower back and shoulders.

too far

If you have a surgery table that you can lean your body against as you work, you may find that it’s comfortable to work with a patient in this position. However, if your table moves when you lean on it, then you may be straining yourself to reach like this. If you do find yourself bending and reaching forward to reach a patient in the middle of the surgery table, consider just positioning the patient closer to you.

patient closer

When we talk about positioning, also remember to look at other objects in the surgery space. Are there objects that the surgeon has to work to avoid, or has to work to reach?

The surgeon in this picture is having to lift her arm and elbow way up to avoid the instrument tray. It’s great having the instruments nearby and in easy reach, but this tray would work a lot better if it was lower or further away, or even if the instruments were on the table between the patients back legs.

Most spay and neuter vets stand for surgery. Its what we were taught in school, and many of us don’t think about sitting unless we have to because of injury or for comfort during pregnancy.

But research with human surgeons showed that they were less fatigued if they either sat for surgery, or alternated between sitting and standing. So if you haven’t tried sitting during surgery, it may be something to consider at least some of the time to increase comfort during surgery.

Sitting for surgery is pretty straightforward when it comes to a small patient. It’s possible to use a standard stool or chair and get close enough to the patient to remain in a comfortable posture

sit for surgery cat

However, it can be more challenging to stay in a comfortable position when doing surgery on a large, deep-bodied patient. A surgeon sitting on a standard stool or chair may have to raise her shoulders and elbows to clear the patient’s body. In this scenario, it’s not possible to lower the table or raise the surgeon’s height because the surgeon’s legs are already in contact with the underside of the table.

sit surgery dog

There is a solution–using alternatives like a saddle-shaped seat or a sit-stand stool can help by allowing the surgeon to remain close to the patient while achieving a better relative height

sit saddle stool

Finally, I want to mention some other aspects of the physical environment in surgery that can affect surgeon comfort and fatigue. Research shows that floor mats can decrease lower limb discomfort and fatigue. They sometimes get credit for helping relieve back pain, but that isn’t supported by the research.

floor mats in surgery

The “perfect mat” will be one that’s not too hard and not too soft. The best mat will be a matter of personal preference. You want something that is cleanable and non-slip. Try out a variety of mats whenever you get the chance to see what feels best to you. Also, look online to ask for a (small) free sample mat from a supplier like Aspen or Smart Step, or a one month trial from other suppliers, so you can see what works for you.

As with floor mats, there is no perfect surgery shoe. But in general, wearing shoes with cushioned soles while in surgery will be the most comfortable, even if you are standing on a floor mat. Some studies of industrial workers found that people who wore different shoes on different days were less likely to have plantar fasciitis than those wearing the same shoes every day. Cushioned athletic shoes or rubber clogs can be good choices.

Next post, we’ll talk about ergonomics when it comes to surgical techniques.

Surgical Ergonomics: Pain in HQHVSN vets

So… is there even a problem? Is ergonomics and pain something we need to spend time thinking about in spay-neuter veterinarians?

In order to figure this out, in 2011 I designed an online survey and collected responses from veterinarians who currently or previously perform spay and neuter surgeries at least 4 hours a week. I asked about hand and body pain, and whether that pain affected their work or activities, whether the pain was related to spay/neuter, and whether they had ever had to miss work because of the pain. I also asked about interventions that they had tried in their surgery day as well as outside of surgery, and about job stress and their satisfaction at work.

Here you can see the profile of the 219 people who responded to the survey.

As you can see, there is quite a range in experience and workload, but overall from what I have seen, this population is pretty representative of the population of people working in the spay neuter field.

When I looked at the prevalence of pain, I found that 99% of the vets in this survey had experienced some musculoskeletal discomfort in the past month. 98% had body pain, and just over ¾ had hand or wrist pain. While this sounds really alarming, other surveys of veterinarians in a variety of practice areas have shown nearly as high prevalence of discomfort.

There is a lot of variability in the severity of discomfort that people experience, and the number of body regions that were uncomfortable. Some veterinarians had worked full time for many years in spay neuter with relatively little discomfort, and others are uncomfortable with a much lighter workload.

This diagram shows the body regions where spay neuter veterinarians most commonly experience discomfort. As you can see, the low back, neck, and shoulders are the most likely to be uncomfortable.

Low back pain is common in humans, and so the high proportion of vets reporting low back pain in the past month is actually in line with other surveys of people.

However, the rate of neck, shoulder, and upper back pain is about 40% higher than what is reported in other surveys of veterinarians. The only surveys where I have seen these high rates of neck pain are in human surgeons.

This diagram shows the areas of the hands and wrists where spay neuter veterinarians most commonly experience discomfort.

The right thumb and wrist are the most commonly painful areas– this was true of the lefties that answered as well as the right handed vets.

One big question this research was trying to answer was “what are the workplace factors that contribute to pain?”

Of the work factors, hours per week in surgery (TIME) had the greatest relative importance in predicting total pain score, followed by years in spay neuter (CAREER). Number of surgeries (LOAD) and surgeries per hour (SPEED) were the least important predictors of pain:

TIME > CAREER > SATISFACTION > LOAD > SPEED

However, these workplace factors only explained a small amount of the pain score. Most of the differences would have to be explained by individual variability, genetics, activities outside of work, and other factors that we may not even think about.

Many studies in many fields have shown that people who have higher job stress or lower job satisfaction experience more work-related pain. In this study, nearly every measure of discomfort increased as people had higher stress and lower satisfaction.

We can’t say from this survey that this is a direct cause-and-effect process, although other studies have suggested that it can be. It may be best to think about pain, stress and low job satisfaction as a cycle that feeds on itself.

So as you’re trying to solve ergonomics problems in your workplace, take the time to consider that working on psychosocial issues may actually improve peoples’ physical comfort as well.

This is a basic summary of my study Prevalence and Risk Factors Associated with Musculoskeletal Discomfort in Spay and Neuter Veterinarians. If you are interested in more details and analysis, you can download and read the entire study here http://www.mdpi.com/2076-2615/3/1/85.

In my next post, I’ll talk about some basic things that spay neuter veterinarians can do to improve their physical ergonomics when they set up their surgical space.