Tag: spay

MASH Clinics

After writing this blog for a few years now, I realized that I haven’t explained what I do for my “day job” as an HQHVSN veterinarian. I am the Executive Director and Veterinarian at Spay ASAP Inc., a MASH-style spay neuter clinic in Vermont and New Hampshire.

(Parts of the content for this post are adapted from Chapter 34 of the textbook, High Quality High Volume Spay Neuter and Other Shelter Surgeries)

What is a MASH clinic?

MASH (Mobile Animal Sterilization Hospital) clinics are a type of mobile spay-neuter program in which clinic staff transport surgical equipment to a venue and set up a temporary surgical space in that location. Surgeries are not performed in the MASH vehicle, but instead utilize an existing space in the community.

American Legion in Claremont NH, a site of many of my MASH clinics.

Examples of clinic locations that I’ve used include animal shelter buildings, church basements, animal care (grooming and boarding) facilities, fire stations, town offices, school gymnasia, senior centers, and many more.

We also used to do MASH clinics in the old farmhouse that housed the offices of the Concord Merrimack County SPCA

MASH programs vary in the number of surgeons, technicians, and support staff, the frequency of surgery days, the number of consecutive days at a single venue, and in mission and organizational structure. Some MASH programs work independently of other humane organizations (independent MASH programs), while others conduct all their work in collaboration with other humane organizations (collaborative MASH programs).  Over the years, Spay ASAP has been hosted by over 15 different humane organizations in Vermont and New Hampshire, and currently we are hosted by 8 different organizations and also have a few additional humane organizations that bring animals to our clinics.

Venues
When the space is small, shelving units for cat crates can optimize the available space

Venues for MASH clinics may be diverse and creative, but with few exceptions, MASH clinics require an enclosed space of a minimum of 1000 square feet (preferred 2000 square feet or greater) that can be maintained at a safe, comfortable temperature, and access to hot and cold water and electricity. In cases where running water is not available, hot and cold water may be brought to the venue. Facilities may be able to provide large nonmedical objects such as folding tables, chairs, and trash receptacles; if not, these items should be provided by the host organization.

Animal Housing
You seriously never know what cats will arrive in.

Since many MASH clinics do not take place in animal care facilities, animal housing often consists of pet carriers or folding wire cages. In these cases, host groups should be prepared to provide crates and bedding for housing dogs, as many owners will not have or will not be able to transport appropriate crates or cages for their dog. Cats and rabbits are generally housed in the carriers in which they arrive at the clinic, and community cats remain in their traps. It is wise to have additional crates available in which to house cats who arrive in inappropriate or inadequate housing.

Yes there are 3 cats in here. That is 30 pounds of black tomcats.
Dogs housed in folding wire cages provided for the day by the host shelter. The sheets over the cages give them some visual barrier between them and keep the room a little calmer and quieter.

MASH Equipment

Equipment requirements for a MASH clinic are similar to those in other clinic types, but all items must be compact and packable, and must have the durability to withstand transport, packing and unpacking daily. Choices for surgery table, surgery light, and anesthesia machines will be influenced by this need for packability and durability.

Vehicle
My first MASH vehicle, a 2006 Scion xB. It was the perfect Spaymobile: boxy with great gas mileage. Also, this picture was taken in early springtime.

For our MASH vehicle, we needed space for 2 people and the necessary equipment. A small minivan, a compact SUV, a station wagon, or a boxy passenger car are adequate for a collaborative MASH program. Small, mass-market vehicles have the advantage of low purchase price, good fuel economy, and low maintenance costs. 

Our current MASH vehicle, a 2016 Kia Soul
Anesthesia Equipment
Our tabletop anesthesia machine. Currently set up with a nonrebreathing system for patients under 5 kilograms

Like many MASH clinics, we use inhalational agents (isoflurane) for some of our patients’anesthesia. We have two anesthesia machines: one for the surgical prep area and one for surgery. This allows animals in the prep area to receive oxygen and anesthetic gas while they are being clipped and scrubbed, so that when they arrive on the surgery table they are on a steady anesthetic plane for surgery.

Tec 4 vaporizer. Boxy but good.

Tabletop anesthesia machines are easy to carry and need not be disassembled to pack in a small vehicle. Our current machines were custom made by Eagle Eye Anesthesia. We use a Tec 4 type vaporizer (the big, square-bottomed heavy ones) since they contain internal baffles that limit the movement of the anesthetic agent. Basically, they continue to deliver appropriate anesthetic concentrations even if the vaporizer is temporarily tipped or upended (ie, when the machine falls out upside down onto the ground when you open the car door).

E-cylinder with oxygen

For oxygen we use portable E cylinders in 2-wheeled oxygen cylinder carts and attached to the anesthesia machine via a regulator and oxygen hose. Oxygen cylinders should be immobilized in the vehicle for transport.

For anesthetic gas scavenging, we usually use passive scavenging (unless we are in a venue with a surgical suite with active scavenging). Passive scavenging options include exhaust through a window, through a hole made in the wall, or using an activated charcoal absorbent canister such as a F/Air canister.

Anesthetic gas scavenging options: out the window, out the wall, or using a charcoal canister.
Equipment Bins

Small equipment and supply items used during the MASH surgery day are packed in bins or totes for organization and ease of transport . We sort our bins by type of items: needles and syringes in one bin, anesthesia tubing and bags in another. We have smaller bins for surgery packs that hold about a dozen packs each.

Bulky supplies are contained in large (18 gallon) bins, and surgical packs are in smaller bins. A rolling cart aids in transporting items into and out of the venue.

A rolling cart is also helpful for venues with level entrances, allowing us to make fewer trips between the car and the surgery area during setup and takedown.

Surgery Table and Light
Surgery table made from old countertop and aluminum legs, placed atop a standard table. An instrument bin to the left of the table is used as an instrument stand, and an architect’s lamp with a compact fluorescent or LED bulb is used as a surgery light.

Some MASH programs require that host organizations provide appropriate height surgery and prep tables and a surgery light at each venue. This is most easily achievable if clinic venues are used repeatedly and are owned by the host organization. In these cases, steel food service tables or appropriate-height tables constructed by volunteers offer alternatives to commercial surgery tables.

At Spay ASAP, we went with a different option and have a portable surgery tabletop, allowing for greater flexibility in temporary surgery venues. A portable tabletop may be constructed using a piece of countertop with folding legs at a fixed or adjustable height that can be placed atop a standard height table– ours was made from a piece of countertop that once went over a dishwasher. We use a small bin (a surgical instrument bin) as an instrument stand.

Surgical prep table elevated on bed risers. An ergonomic standing mat is provided for the veterinary technician.

Other portable table alternatives would include using a small or standard folding table with bed risers or an adjustable-height folding table. We also elevate the surgical prep table to the appropriate height for the veterinary technician using bed risers or blocks. 

For surgical lighting, we use an architect’s lamp with a compact fluorescent bulb of 23 watts or greater, or LED bulb of 16 watts or greater (equivalent to a 100-watt incandescent bulb). Alternatively, a head lamp may be used, but I find the weight of these lamps to be uncomfortable and am less impressed by the lighting quality.

Patient warming

Selecting a surgical patient warming device for MASH can be challenging, as some are too bulky to transport in small MASH vehicles, and those containing water may be difficult to transport due to spilling or freezing water during transport and storage (I used to use a Gaymar pump and water blanket but got frustrated by leaks and spills and the risk of freezing). A low-voltage conductive polymer fabric heating pad (such as Hot Dog or ChillBuster or Warm Blood if you can still find them) can be used, as they are compact and fairly durable.

Any postoperative warming devices that we use, such as heating pads, rice socks, or electric blankets, are supplied by the host organization, and should be used with caution (ie, no skin contact with the pet, and used only with direct human supervision) to avoid thermal burns. 

Additional Equipment
Net, squeeze cage, and kevlar gloves.

Additional equipment transported by the MASH clinic includes a scale to weigh surgery patients, anesthesia monitor(s) such as a pulse oximeter or capnograph, anti-fatigue floor mats, and an insulated container for vaccines.

Safety equipment such as cat net, animal handling gloves, syringe pole, squeeze cage, and dog muzzles should be included, as many venues will not have adequate handling equipment. An additional useful piece of handling equipment is a snappy snare, which is a 3- to 5-foot-long stiff leash that allows the leash to be placed on the dog from a distance, and is useful for safely applying a leash to a frightened dog in a crate or kennel.

“Home Base”
Entrance to our rented room above a veterinary clinic

MASH clinics require a small area (minimum 10 x 10 feet) for receiving and storage of supplies and medications. At Spay ASAP, we rent a room on the second floor above a veterinary hospital. The ideal space would be easy to access with a convenient geographic location, a convenient physical location (first floor, near supply delivery area), and is temperature controlled for safe medication storage. Our space isn’t ideal from the point of view of deliveries, but we do have direct access via the fire escape.

If the MASH program is part of existing organization with a physical building, the MASH clinic can use this space.

If the MASH is a new organization or has no suitable site, possible sites include the home of a staff member or a rental space.  Renting space from an existing animal care organization such as a veterinary clinic offers the advantage of on-site staff to receive deliveries of temperature-sensitive items such as vaccines or medications.

Inside our storage room: just enough space for backstock and storage of the supplies that don’t fit in the vehicle

If the home base is to be used for surgical pack preparation, it should contain or allow access to laundry facilities (unless all drapes and pack wrappers are disposable) and electricity, and should be large enough to accommodate pack assembly and an autoclave. During times when we have prepared packs in our rental space, we have rented additional space in order to have table space to prepare packs.

How to set up a MASH program: organizational structure and details

Everything from here on is more nitty gritty organizational detail, including more words, no pictures, and more generalizable information. It draws heavily from the MASH textbook chapter. It may be a bit too detailed for a blog post, but I wanted to get this information out and available for anyone who is really interested in starting up this type of clinic.

Can I MASH here? Legal issues:

Before considering a MASH clinic, be certain to check any relevant state or provincial veterinary practice acts and local regulations to be sure that MASH clinics are permitted. Some states and provinces require premise permits for any practice location, which may preclude MASH clinics. However, in some cases, states or provinces that require premise permits may allow exemptions for MASH clinics if asked in advance.

Who should MASH?

MASH clinics are adaptable and there are not specific prerequisites for regional population density or shelter animal intake. They are suitable for rural areas where low population density does not easily support a stationary clinic (like the border area of Vermont and New Hampshire), as well as for densely populated urban areas. MASH clinics are valuable for local shelters that wish to provide in-house HQHVSN, but either cannot afford to build and equip their own surgical suites, or that have surgical areas but lack veterinary staff. MASH clinics are also suitable for international and remote area spay-neuter programs.

For a veterinarian with surgery skills seeking spay-neuter work, establishing a MASH clinic can be one of the fastest and lowest cost ways of starting a HQHVSN clinic. This is what I did when I started Spay ASAP in 2006, and we went from registering the nonprofit in March to performing our first surgery in early June. In most cases, veterinarians who choose this route should be willing to operate the business aspects of the clinic and be able and willing to work with shelters and humane organizations in their target region.

In some cases, programs with limited startup funds may wish to offer surgery services before fundraising is complete or before a clinic site is located for a future stationary clinic. In this case, a MASH clinic may serve as a temporary economical option during the development of the HQHVSN program. Since any equipment purchased for MASH can be used in other models, the MASH clinic provides the opportunity for quicker startup without loss of equipment investment.While MASH programs are diverse, this chapter will focus on programs that utilize paid veterinarian(s) and technician(s) and operate within a prescribed region (as opposed to national or international scope). However, many of the descriptions in this chapter may be adapted to MASH programs that operate internationally and/or use volunteer veterinarians and technicians. For information on setting up international or remote area MASH clinics, the reader is referred to Susan Monger’s chapter on Operating a field Spay Neuter Clinic in the Field Manual for Small Animal Medicine.

Independent versus Collaborative MASH programs

MASH programs can operate their clinics independently of other humane organizations in a region or may collaborate with other humane or community organizations to host their clinics. Some MASH clinics may use a combination of these two approaches. There are advantages and disadvantages to each of these models. My own Spay ASAP clinics are collaborative MASH clinics so I’m biased towards that model and find it to be sustainable over the long term.

Collaborative MASH programs

Collaborative MASH programs are generally small organizations that collaborate with various local humane or community groups that act as their hosts in the communities within their service area. These host groups (or “ground teams”) must provide the venue and personnel, consisting of 2-5 staff members or volunteers, while the MASH program (or “surgery team”) provides the veterinarian, the technician, and all surgical supplies and equipment. The host organization is responsible for scheduling, admitting, and discharging patients, and for printing, preparing, and distributing clinic paperwork such as medical record forms, liability releases, discharge instructions, rabies certificates, and neuter certificates. Host groups are often required to provide non-medical supplies such as tables, chairs, animal bedding, extra pet carriers, and trash receptacles. In these collaborative programs, the MASH group generally works with several different host organizations throughout their service area to host clinic days. At times, more than one local humane group may work together to host a MASH clinic. 

Collaborative MASH programs empower small humane organizations and shelters to host their own “Spay Days,” affording them the opportunity to enhance their community relations and outreach. The opportunity to host and assist with a MASH clinic enables staff and volunteers at host shelters to do something “fun” and different, compared to their usual shelter duties. These collaborations also allow opportunities for MASH clinic staff to share information and best practices for shelter medicine and HQHVSN with their host organizations.

Generally, it is the responsibility of the MASH organization to provide training and mentorship to new or potential new host organizations. Before hosting their first clinic, host organizations will need to know how to schedule the appropriate surgical load and how to determine the number and skill level of volunteers required. They need to understand the paperwork and be able to provide appropriate pre- and post-operative instructions to clients. An in-person meeting between the MASH organization and potential new hosts along with written instructions on hosting protocols and expectations is recommended prior to the first clinic.

Once a MASH organization has established relationships and carried out clinics with one or more host organizations, potential new host organizations can benefit greatly by visiting with and observing existing host organizations during MASH clinic days. This peer-to-peer mentorship helps new host organizations develop their own protocols and systems and allows them to see clinic flow and ask questions before their first clinic. In some cases, this mentorship may even continue, with representatives from existing host organizations attending the first few clinics sponsored by new host organizations, smoothing their transition into their role as host.

Advantages of the collaborative MASH model include flexibility and decreased operating costs. Staffing costs are decreased for the MASH organization because of the symbiotic relationship between the MASH organization and their hosts. The MASH organization pays only one veterinarian and one technician per day, in addition to an after-hours surgical pack preparation staff, and relies upon the host organization to provide additional resources (2-5 staff or volunteers, and venue). The hosts are motivated to provide this because they need the MASH program’s staff, equipment, and expertise in order to offer affordable HQHVSN clinics.

In contrast to an independent MASH clinic, the collaborative MASH clinic requires a relatively small vehicle given the small staff and minimal equipment required. Purchasing a smaller vehicle results in a lower initial purchase price, as well as lower ongoing fuel and maintenance costs. This decreased operating cost often means that a collaborative MASH clinic is able meet their budget entirely via low-cost fees for service, without additional fundraising.  

Independent MASH programs

Independent MASH programs have sole responsibility for scheduling the venue, booking patients, securing volunteers and staff, and admitting and discharging patients. The independent MASH model is more likely to be adopted by large, pre-existing organizations, by new HQHVSN programs planning to transition to stationary clinics in the future, or by organizations doing MASH clinics intermittently. This is because developing and training the network of collaborating host organizations that is required for a collaborative MASH clinic takes time and effort. For large, established organizations that have the resources to perform ground team tasks in addition to surgical team tasks, this extra task of collaborator development may be unnecessary. For MASH clinics that operate intermittently, the collaborative relationships may languish and be harder to maintain.

In an independent MASH clinic, staffing and finances are likely to be similar to a stationary clinic or self-contained mobile surgery unit, unless adequate, reliable volunteer staffing is available. Minimal required staff would consist of a veterinarian, a veterinary technician, one or more veterinary assistants, and administrative staff for record keeping, patient booking and reception. 

Independent MASH clinics may require larger vehicles than collaborative programs to transport staff, surgical equipment, and some nonmedical items such as animal bedding and extra pet carriers or crates. Since the staffing for this model of clinic is similar to that of a stationary clinic, the costs are higher as well, making this model harder to sustain financially than collaborative MASH clinics. However, independence can offer the advantage of more predictability by utilizing more consistent clinic staff and by not needing to rely on other humane groups to schedule clinic dates and locate suitable staff and volunteers.

Organizational structure

MASH clinics may be established within any organizational structure, including nonprofit, for profit, and government or tribal entities. In some cases, MASH clinics may represent a single program within a large, diverse existing organization. For example, an animal shelter with an in-house spay-neuter clinic may develop a MASH program to reach certain communities in their service area. In others, a new organization is formed for the purpose of offering MASH clinics, and this organization exists solely for the purpose of offering MASH clinics. 

Financial investments and ongoing costs

Financial requirements for a MASH clinic are generally much lower than for a stationary clinic or self-contained mobile unit. There will also be some differences in the initial investments between MASH clinics following a collaborative model versus an independent model. In all MASH clinics, the major initial costs will include acquisition of a vehicle, surgical and anesthetic equipment, initial consumable supplies (for example, drugs, vaccines, syringes and needles, gauze sponges, antiseptics, and suture material) and an autoclave. In cases in which the MASH clinic already has access to a suitable vehicle, or if the MASH vehicle is purchased with a car loan, the initial investment to start a collaborative MASH clinic will likely range from $20,000- $35,000.

Ongoing costs for MASH will include personnel costs (salaries, wages, benefits, payroll taxes, workers compensation), consumable supplies, and vehicle gas and maintenance. Most MASH clinics will also need to rent a small, climate-controlled “home base” physical space for safe storage of consumable supplies (see “home base” section above). 

Because overhead costs are low, it is possible to sustain a collaborative MASH clinic with low-cost fees for services, without additional fundraising. In cases where extremely discounted or free surgeries are to be offered, additional fundraising and grant writing by the MASH clinic or by one or more host organizations will be required to subsidize program costs.

Personnel

Minimal personnel requirements for a collaborative MASH clinic generally consist of one veterinarian and one veterinary technician. Some MASH programs employ additional staff for instrument care or for management. In many collaborative MASH programs, the veterinarian and technician handle instrument care and management responsibilities without additional staff. For example, the veterinarian serves as the program director/manager, and the technician assumes the responsibility for preparing surgical packs.

Independent MASH programs require additional personnel including veterinary assistants and administrative staff. The staffing model for these clinics is similar to that for a stationary or mobile self-contained clinic.

Surgical capacity

Surgical capacity for a MASH clinic should be comparable to other HQHVSN models, although in many MASH clinics, only one surgery table is available, so surgical flow and resulting speed is somewhat slower than in a fully-equipped stationary clinic. However, unlike in some self-contained mobile units, physical space for animal housing need not be a limitation for MASH clinics. Approximately 5 hours of surgery time is a full day for a MASH clinic, and this may consist of as few as 15-20 dogs or as many as 50-60 cats for one veterinarian depending on surgical speed and species and sex composition of the patient load. 

Timeline

Startup time for a MASH program can vary.  In the case of collaborative MASH programs, startup may be delayed if collaborating organizations need to be identified and persuaded. However, if collaborating organizations are prepared to host clinics immediately, a MASH program can start up in less than 3 months once finances are obtained.

Protocols 

As with all HQHVSN clinics, MASH clinics should adhere to the ASV Guidelines for Spay-Neuter Programs. Surgery techniques, patient selection, and disinfection and sterilization of equipment are no different than in other HQHVSN clinics. Anesthesia and analgesia protocols are similar to those in stationary clinics, although care must be taken to select protocols that are suitable for same-day discharge of patients. As with all clinic types, proper medical record-keeping is essential, and clients must be provided with written and verbal postoperative instructions. 

Post-operative care

As with other clinic types, there is a need to develop a postoperative care plan for emergencies and client questions. In most cases, this is achieved by providing a phone number to clients to contact MASH clinic staff in case of questions or emergencies. This phone may be carried by a veterinarian or a technician who can answer client questions and concerns and triage cases requiring veterinary care. For independent MASH clinics, administrative staff may carry this phone, triage calls, and refer medical questions to a veterinarian. Emergencies and rechecks will generally need to be seen by outside veterinary hospitals, as the MASH staff may be distant from the animal in question and may have no available facility in which to see patient rechecks. It is up to the MASH program to set policies with regards to client reimbursement or payment to outside veterinary hospitals seeing MASH clients. In many MASH clinics, as with other HQHVSN clinics, outside care is reimbursed if related to the surgical or anesthetic procedure, and if the client has generally followed post-operative instructions.

Some MASH programs have established relationships with specific local veterinarians or emergency clinics within their service areas who are willing to provide emergency care, and in some cases, the clients may be provided with this contact information instead of or in addition to contact information for the MASH clinic. Other MASH programs establish relationships with local practices as needed, as the geographical areas covered by some MASH programs are large enough that specific local relationships may be difficult to establish. Regardless, it is essential that the MASH clinic have a plan in place for how they will address follow-up or emergency care for their patients.

Surgical Instruments and their Care

In most cases, MASH clinics have no on-site autoclave. Most surgical instrument care, including ultrasonic cleaning, pack preparation and autoclaving, takes place after hours or between clinic dates. Thus, many small, collaborative MASH clinics maintain enough sterile surgical packs for multiple (2-3) days-worth of surgery or schedule time in between surgery days to provide time for packing and sterilization. This may be especially important if the pack preparation is performed by staff who are also members of the traveling MASH clinic team.

Surgical instruments should be soaked to remove organic debris and cleaned by hand by volunteers at the surgical venue, then rinsed and returned to the transport vehicle to be transported back to the home base with the surgical team. Further instrument cleaning, laundering of drapes and pack wrappers, pack preparation, and sterilization may occur at the MASH clinic’s home base, or alternatively may take place in a staff member’s home. This at-home pack preparation and autoclaving may be advantageous if the staff member lives far from the home base, or if the staff member has household obligations (such as small children) that make after-hours travel to the home base difficult.

MASH: The Day of Surgery

MASH clinics are typically located in different venues with a different layout each day. Collaborative MASH clinics work with different assistant staff each day, as provided by the host organization. These changes can affect clinic flow and efficiency, and they require the MASH veterinarian and technician to adapt to a variety of new situations and circumstances.

Setting up the clinic

In a collaborative MASH clinic, the host organization’s staff admits patients before the veterinarian and technician arrive, or while the veterinarian and technician are unpacking and setting up. In each new clinic venue, the MASH veterinarian and technician must plan the layout and flow for the clinic. The veterinarian’s and technician’s workspaces are re-created as consistently as possible but must be adjusted to accommodate the locations of windows, electrical outlets, and doors. Flow through the clinic should be optimized, although not every venue will lend itself to smooth flow between preop, prep, surgery, recovery, and postop areas.

Clinic Flow

Clinic flow in a MASH program may be somewhat slower than flow in a stationary clinic.  Typically, a MASH clinic has one surgery table per surgeon, such that the surgeon must wait while patients are exchanged on the table. To improve flow while working on cats, the surgeon may alternate male and female cats, castrating male cats on a side-table or countertop while female cats are exchanged on the surgery table. MASH clinics also usually have only one prep station, which may be the rate-limiting step during fast surgeries. Also, since clinic layout and staffing vary between locations, ideal flow may not be achievable at each clinic site.

Clinic Day

The MASH clinic day includes travel, setup, and re-packing, in addition to the usual tasks related to operating a HQHVSN clinic such as performing patient exams, anesthetic procedures, and surgery. The total day length for the veterinarian and technician may be 11 hours, whereas the surgery time is only 4-5 hours. Thus, more than half the staff’s time is spent driving, setting up, and re-packing the surgery area. This time budget may be improved somewhat by changing clinic policies: driving time may be reduced by restricting the travel radius, and setup and takedown time may be reduced if the clinic is located in the same venue for multiple days.  

The time required for these additional tasks of driving, setup, and packing means that MASH clinics are not the most efficient clinic model in regards to use of the veterinarian’s and technician’s professional time. A MASH that employs only one veterinarian and one technician may be operating “full time” (36-40 hours a week) with just 3 clinics—or about 100 surgeries—per week, if the technician is also preparing packs between surgery days, and the veterinarian is acting as administrator and business manager. However, despite achieving fewer surgeries per full-time veterinarian, the lower overhead costs mean that the cost-per-surgery is equivalent to that of a stationary clinic. This allows MASH clinics to pay hourly wages to the veterinarian and technician that are on a par with, or in some cases greater than, stationary or self-contained mobile HQHVSN clinics.

MASH clinics provide a flexible, low-cost, high-quality method for delivering spay-neuter services. The MASH clinic’s versatility, adaptability, relatively low capital investment, and short time to start up are the particular strengths of this clinic type, and makes these clinics useful both as short-term solutions as well as long-term, sustainable HQHVSN providers.

I hope you all enjoyed this intro to MASH clinics!

Needle holder grasps in surgery

For the spay-neuter vet, pandemic social distancing has been a slow time. I’ve had plenty of opportunity to stay home sleeping, baking, playing Pokemon Go and watching birds (often these two are simultaneous activities), eating fiddleheads, and seeing spring unfurl. With services starting to reopen, I’m getting ready to go back to work on Monday, so my thoughts have started to turn back to surgery and ergonomics.

During these idle months I’ve had some time to look through old ergonomics articles and projects with an eye to assembling them into something useful. This week I found myself thinking about needle holder grasps (after a Facebook conversation) and thought to look back at my masters thesis in ergonomics. The topic was a comparison between palm grasp and tripod (fingers in the rings) grasp for needle holders. The aim was to compare users of the two techniques both by surveying them about pain and by measuring the muscular strain in their forearms. In keeping with my desire to share incidental and independent research results, I’m publishing the thesis at the bottom of this blog post (never fear, we were limited to 5000 words).

If you thought this article would answer the question of whether palm grasp is better than placing fingers in the rings of the instrument, think again! The utter messiness of the results and the difficulty of drawing conclusions about the different grasp types was why I never published it anywhere (until now! here!). But I learned a lot from the research about individual variability and the diversity of supposedly standardized techniques. This paragraph taken from the Discussion sums up what I learned:

The amount of grasp diversity between participants, the use of non-standard instrument grasps, and the variability in individual participants’ grasps, were surprising findings in the current study. Participants were often unaware of the grasp that they used. Several described themselves using a grasp different from the one that they actually used, and some noticed in the midst of the experiment that they were using a different grasp from what they had described. Even within a single grasp type, the participants varied in their movement patterns and degrees of forearm rotation and wrist angulation. 

So while I can’t promise any groundbreaking information about which grasp style is ergonomically superior, I do think there are some interesting photos and tidbits in this article. I also think that the diversity of successful techniques leaves clear opportunity for individuals to modify their grasping and suturing technique if and when it becomes painful or problematic for them.

I hope you all are well, and staying safe. Enjoy!

Electromyographic analysis of needle-holder grasps used while suturing

A thesis in partial fulfillment of Masters of Science in Health Ergonomics, University of Derby, February, 2015

Abstract

The current study examined variations in muscular force and muscle use patterns between surgeons using different grasps while suturing. Fourteen (4 male, 10 female) right-handed veterinarians were recruited into one of two groups, palm or tripod, depending on their usual, preferred needle holder grasp. Participants completed the Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) and the Cornell Hand Discomfort Questionnaire (CHDQ), and then performed a suturing task using their preferred grasp. Four muscles in the right forearm region were selected for electromyographic (EMG) recording: extensor digitorum communis (EDC), flexor carpi radialis (FCR), flexor carpi ulnaris (FCU) and abductor pollicis longus/ extensor pollicis brevis (APL). 

The 1-week period prevalence of MSD was 92.9%, with 13 of 14 participants reporting pain. Of these, 7 (50%) reported hand pain, and 12 (85.7%) reported body pain. Observed grasps differed from those reported by participants, with five using exclusively tripod grasp with the thumb and ring finger in the instrument rings, two using a modified tripod grasp with thumb and middle finger, three using palm grasp for suture placement and tripod grasp during needle extraction and knot tying, three using palm grasp with no fingers in the instrument rings, and one using palm grasp with the ring finger in one instrument ring. The static load (10th% APDF) on each of the four muscles ranged from 0.9 to 10% MVC, with greater mean values for the extensor EDC than for the flexors FCR and FCU. Degrees of forearm pronation and supination ranged from 80 to 180 degrees, and degree of rotation was positively correlated with the total pain score. Future investigation into the characteristics and benefits of various grasps is warranted, so that practical advice on reducing strain and MSD risk can be offered to surgeons.

Introduction 

High-volume spay-neuter is a growing practice area in veterinary medicine in the US (Looney et al., 2008) in which veterinarians may perform over 30 surgical procedures daily, and some individuals spend over 35 hours each week performing surgery (White, 2013). These procedures are of limited variety compared with general surgery, and frequently involve static postures and repetitive manual tasks. Repetitive work is associated with increases in upper limb discomfort, tendinitis, and carpal tunnel syndrome in people who engage in manual work (Latko et al., 1999), and static postures, or isometric positions where little movement takes place, multiply the risk for musculoskeletal disorders attributable to those postures (Esser et al., 2007). While work in high volume spay-neuter has many qualities that would appear to put veterinarians at risk for MSD, there is limited research on the effects of this repetitive surgical workload on veterinarians, and no research exploring ways to mitigate these effects. 

A single cross-sectional study (White, 2013) has investigated musculoskeletal discomfort (MSD) in veterinarians working in high-volume spay-neuter. The one-month period prevalence of MSD was 99.1%, with 76.7% experiencing hand or wrist pain and 98.2% experiencing body pain. Hand discomfort was most commonly reported in the right thumb and/or thumb base (49.8%) and the right wrist (37.9%). This rate of hand/wrist discomfort is 1.5 to 2 times the prevalence of upper limb MSD experienced by veterinarians in general practice (Kozak et al., 2014; Scuffham et al., 2010; Smith et al., 2009), and greater than the prevalence in surgeons in human surgical practice (Adams et al., 2013; Soueid et al., 2010). Body discomfort in spay-neuter veterinarians was most commonly reported in the lower back (76.7%), shoulders (72.6%), and neck (71.7%). Three-quarters of veterinarians experiencing hand, finger, and thumb MSD attributed their MSD completely to their work in spay-neuter. Increasing career length, increasing weekly hours in surgery and decreasing job satisfaction were the work-related factors with the greatest relative contribution accounting for variation in hand pain severity and total pain. While 94.4% of respondents felt that posture and positioning during surgery is important, only 30.6% had received any instruction in posture, positioning, or ergonomics in surgery (White, 2013).

The high prevalence of upper limb MSD in spay-neuter veterinarians may be related to the high volume and limited variety of surgical tasks undertaken, and thus the repetition of a limited diversity of hand movement patterns performed in the workday. Anecdotally, some spay-neuter veterinarians have attributed their lack of upper limb MSD to their use of a palm grasp when using needle holders, instead placing their fingers in the instrument rings. 

Textbooks and authors vary in their use of terms to describe instrument grip. Anderson and Romfh (1980) describe the “palmed grip” in which the surgeon grips a long needle holder by the shanks, away from the finger rings and ratchet, making it impossible to open or close the ratchet while using this grip. This is in contrast to Seki’s (1988) diagram of “grip 2,” in which the finger rings and ratchet are held in the palm of the hand, allowing operation of the ratchet mechanism. This is the same as the “modified thenar eminence grip” described by Toombs and Bauer (1993), and also described (though unnamed), two decades earlier (Weiss, 1973). More recent sources (Kirpensteijn & Klein, 2006; Yoon & Mann, 2011) name this same grasp the “palm grip.” Yoon and Mann (2011) use the term “thenar eminence grip” to describe a grasp in which the needle holder is grasped in the palm, with the tip of the ring finger placed through one finger ring. The same grasp is elsewhere called the “thenar grip” (Anderson & Romfh, 1980). Booth (2013) repeats the descriptions and terms used by Anderson and Romfh (1980), except that, in the illustration of Booth’s “thenar grip,” the fourth finger does not enter the finger ring, making this “thenar grip” resemble the “palm grip” described above.

Current consensus appears to favor “palm grip” to describe the grasp in which the finger rings and ratchet are held in the palm, with no fingers in the finger rings. The comparison grip, utilizing thumb and ring finger in the instrument rings, has been called the three point grip (Kirpensteijn & Klein, 2006), the thumb-ring finger grip (Anderson & Romfh, 1980), the thumb-third finger grip (Toombs & Bauer, 1993) [this grip is pictured with the fourth phalanx in the instrument ring, despite the use of “third finger” in the name], and thumb-ring finger (tripod) grip (Booth, 2013). For the current study, the term “tripod grip” has been chosen for its brevity and clarity.

The research comparing the attributes, physics, and precision of these grasps during open (non-laparoscopic) surgery is limited. One study found greater suturing precision among surgeons using palm grasp as compared to tripod grasp (Seki, 1988), and the author speculated that the palm grasp was more stable and reduced the difference in angle between the hand and the instrument. Despite the limited research comparing the grasps, surgical textbooks make assertions about their qualities and disadvantages. Toombs and Bauer (1993) state that the modified thenar eminence (palm) grip results in imprecise release of the needle, making this grip poorly suited to delicate suturing compared to the thumb-third finger (tripod) grip. This contrasts with Seki’s (1988) finding of greater accuracy when using the palm grip.

Several studies have used electromyography (EMG) to compare the ergonomic aspects of various grasps. Surface EMG uses electrodes on the skin to detect the electrical activity produced by the summed motor unit action potentials in the muscle of interest (Criswell, 2011). EMG signal strength has an approximately linear relationship with muscular force, making it useful in ergonomics for determining the amount of individual muscle involvement in a given task, and allowing evaluation of strain on the tissues (Hägg et al., 2004). One study comparing two different grasp styles on a laparoscopic instrument found differences in EMG amplitude in several forearm muscle groups, leading to the recommendation of a specific, palm-grasp style in certain circumstances (Berguer et al., 1999). A second study comparing various laparoscopic handle designs found that the pattern of EMG activity—the proportional use of each measured muscle—is characteristic of the handle (and thus the grasp) used, rather than being task-specific (Matern et al., 2004). A similar EMG study of handwriting grasp styles also showed characteristic EMG activation patterns for each grasp style (de Almeida et al., 2013).

The amplitude probability distribution function (APDF) is a means of EMG data reduction that is used to characterize the muscular load profile over a period of time (Hägg et al., 2004). The calculation reveals the cumulative probability for EMG amplitude over time, and can be normalized for each subject to a percentage of their maximum voluntary contraction (%MVC) for that muscle. APDF levels are often reported as 10th, 50th, and 90th percentiles, with 10th %APDF representing static load, 50th% APDF median load, and 90th% APDF considered peak load for that muscle (Szeto et al., 2009). 

The current study aimed to examine variations in muscular force and muscle use patterns between surgeons using a palm grasp versus a tripod grasp while suturing. It was expected that the results could be used to guide surgeons in selecting which grasp to use routinely, and indicate which grasp to choose or avoid to decrease strain on specific muscles and their associated tendons and ligaments.

Methods

Participants 

A total of 14 (4 male, 10 female) veterinarians were recruited for the present study. Participants were recruited into one of two groups, palm or tripod, depending on their usual, preferred needle holder grasp pattern. All subjects were right-handed. 

Participants were recruited at two veterinary conferences: the North American Spay/Neuter Conference in Austin, Texas and the Silicon Valley Spay & Neuter Symposium in Milpitas, California, in 2014. Two additional veterinarians were recruited at a spay/neuter strategy meeting in Burlington, Vermont. Consent to participate was obtained from each participant before the study began. The study was approved by the Psychology Research Ethics Committee at the University of Derby

All participants in the study were asked to complete a questionnaire prior to participation. Demographic data including year of birth, year of graduation from veterinary school, whether they have obtained any specialty certification, and current hours per week performing surgery were recorded. Participants were shown pictures of “palm” and “tripod” grasps, and asked which grasp they use, or, if a mixture of grasps, in what proportion they use those grasps. They were also asked when they began using their current instrument grasp, whether they have used a different grasp at any point in their career, and why they have chosen their current instrument grasp.

In addition, participants were asked to complete the Cornell Musculoskeletal Discomfort Questionnaire and the Cornell Hand Discomfort Questionnaire regarding any discomfort in the past week. These questionnaires allowed the determination of the location, severity, and impact on work and daily activities.

Electromyography

Four muscles in the right forearm region were selected for the electro- myography (EMG) study: extensor digitorum communis (EDC), flexor carpi radialis (FCR), flexor carpi ulnaris (FCU) and abductor pollicis longus/ extensor pollicis brevis (APL). The I-330-C2+ system (J&J Engineering, Inc., Poulsboro, WA) was used to capture the surface EMG data, with a bandwidth of 10-400 Hz and a common mode rejection ratio of 100 dB, with input impedance 10 GW and a notch filter of 60 Hz. The EMG signals underwent a 16 bit analogue to digital (A/D) conversion at a sampling frequency of 1024 Hz.

Bipolar Ag-AgCl surface electrodes (Norotrode 20, Myotronics, Inc, Kent, WA) with an inter-electrode spacing of 22 mm were used. The ground electrode was an 1 3/8 inch Ag-AgCl electrode (SilveRest, Vermed, Bellows Falls, VT) that was placed on the right upper arm above the elbow.

The locations for EMG electrodes were adopted from Perotto (2011) and Criswell (2011). Before attaching electrodes, the skin was prepared by abrading with a gauze sponge. After electrode placement, the skin impedance was checked using the impedance testing function in the I-330-C2+, and impedance below 900 KW was considered acceptable. 

Prior to starting the experiment, subjects were asked to perform two trials of resisted isometric maximum voluntary contractions (MVC) of 5 seconds each against manual resistance for each muscle. 

Video Recording

Each session was recorded using 1080p HD video at 30 frames per second using an iPhone 5S (Apple, Inc, Cupertino, CA). A single, front view recording of each participant was made, and markers in the EMG recording allowed synchronization of video and EMG recordings. 

Video recordings were used to examine posture during surgery using Rapid Upper Limb Assessment  (McAtamney & Corlett, 1993). RULA assessment was made at the time in the work cycle when the highest loads occurred, assessing the participant’s dominant arm, and applied just to the experimental condition (not extrapolated to a “typical” work day).

Protocol

Each participant stood at a table adjusted to their preferred height. Participants were then asked to use an 5.5 inch Olsen-Hegar needle holder (Spectrum Surgical, Stow, OH) and thumb forceps to place five simple interrupted sutures in a polyvinyl alcohol synthetic chamois skin model using 3-0 Monocryl suture on a 40 mm, ½ circle taper needle. Measurements taken during the first suture were not included in the analysis, in order to allow the surgeon to become familiar with the materials and task.

Data Processing and Analysis

The USE3 Physiolab (J&J Engineering, Inc., Poulsboro, WA) software was used to process the EMG data. Data processing involved full-wave rectification and smoothing with root-mean-square (RMS) with a 250 ms window. These data were then exported to Microsoft Excel to compute the MVCs for each muscle, and to SPSS to compute the 10th%, 50th% and 90th% levels of Amplitude Probability Distribution Function (APDF) for the four muscle groups. 

            Pain severity for each body region was calculated for each participant using the scoring guidelines accompanying the CMDQ and CMHQ (Hedge, n.d.). Frequency scores were assigned: never = 0; 1–2 times a week = 1.5; 3-4 times a week = 3.5; every day = 5; several times a day = 10. Discomfort scores were assigned: slightly uncomfortable = 1; moderately uncomfortable = 2; very uncomfortable = 3. Daily interference scores were assigned: not at all = 1; slightly interfered = 2; substantially interfered = 3. Pain severity was obtained by multiplying the frequency, discomfort, and interference scores for each body part. Total body pain severity for an individual was obtained by summing all the body pain severity scores for that individual. Total hand pain scores were obtained by summing the hand pain severity scores for that individual. Total overall pain scores were obtained by summing the hand pain and body pain scores for that participant. 

            Demographic, MSD, and EMG data were entered into SPSS. Pearson correlations were used to assess relationships between MSD and demographic and postural characteristics. APDF levels of different muscles were compared using paired sample t-tests.

Results

Demographics

            A total of 14 veterinarians participated in this study, including 10 (71.4%) females and 4 (28.6%) males (Table 1). The median age of participants was 43 years, with a range of 31 to 62 years of age. Median time since graduation from veterinary school was 13.5 years, with a range of 4 to 32 years. None of the veterinarians had obtained board specialty certification. Participants spent a median of 17.5 hours a week in surgery, with a range from 0 to 35 hours weekly. Two participants did not regularly perform surgery in their current jobs: one was in a management position and performed surgery on an as-needed basis, and the other was seeking employment. Both of these veterinarians had several years experience performing surgery.

Table 1. Participant demographic, workload, instrument grip, and discomfort data

Musculoskeletal Discomfort Prevalence 

The self-reported 1-week period prevalence of MSD was 92.9%, with 13 of 14 participants reporting pain. Of these, 7 (50%) reported hand pain, and 12 (85.7%) reported body pain. All who reported discomfort also reported that it interfered at least slightly with their ability to work. In the right hand, the most commonly reported areas of MSD were the distal thumb (first proximal and distal phalangeal area; 28.6%), and the thumb base (first metacarpal area; 28.6%). MSD was reported in some portion of the right thumb [phalangeal and metacarpal areas] by 42.8% of participants. Body MSD was most commonly reported in the lower back (71.4%), right shoulder (50%), and neck (50%). 

Pain severity was not correlated with age (r (12)= 0.233, p= 0.424) or hours per week in surgery (r (12)= 0.005, p= 0.987), and was unrelated to the sex of the participant (t(12) = -1.415, p=0.182).

Grasp Characteristics

            Eight of the participants reported using tripod grasp all or most of the time, and 5 reported using palm grasp all or most of the time. The remaining surgeon reported using the two grasps equally. Eleven participants (78.6%) reported having adopted their current grasp in veterinary school or before, whereas 3 participants (21.4%) reported to have modified their grasp after graduation from school.

Actual observed grasps differed from those reported by participants (Figures 1-5). Video analysis revealed that 5 participants used exclusively tripod grasp with the thumb and ring finger in the instrument rings (1, 4 tripod), one of whom routinely placed her fifth finger in the instrument ring with her fourth finger. Two participants used a modified tripod grasp with the thumb and middle finger (1, 3 tripod) in the instrument rings. Three participants used palm grip for suture placement (driving the needle through the substrate) and switched to 1, 4 tripod grasp during needle extraction and knot tying (palm/tripod). Three participants used palm grasp with no fingers in the instrument rings, and one participant used a palm grasp with the ring finger in one instrument ring.

Figure 1. Instrument grasps used by study participants.: 1,4 tripod grasp
Figure 2. Instrument grasps used by study participants: 1,4 tripod grasp with fifth finger in ring.
Figure 3. Instrument grasps used by study participants: 1,3 tripod grasp
Figure 4. Instrument grasps used by study participants: Palm grasp.
Figure 5. Instrument grasps used by study participants: Palm grasp with fourth finger in ring.

Electromyography

Results of electromyographic recordings are presented in Table 2. In one participant, EMG readings were not obtained for FCU activity, as the electrodes loosened during the experiment.

Table 2. Results of low (10th % APDF), median (50th % APDF), and high (90th % APDF) muscle activities for all muscle groups and each participant. All values are expressed as a percentage of the maximum voluntary contraction (%MVC) for that muscle in that participant.

EDC: extensor digitorum communis, FCR: flexor carpi radialis, FCU: flexor carpi ulnaris, APL: abductor pollicis longus/ extensor pollicis brevis. 
*FCU electrodes loosened on Participant 7, preventing data collection from this muscle

The 10th % APDF, representing the static load on each of the four muscles, ranged from 0.9 to 10% MVC, with greater mean values for the extensor EDC (M = 5.51; SD = 1.37) than for the flexors FCR (M = 3.27, SD= 1.62) and FCU (M = 3.33, SD=1.53). These differences were statistically significant, with EDC:FCR t(13) = 5.082, p<0.001 and EDC:FCU t(12) = 4.824, p<0.001, two tailed. This differential activation level persisted between the EDC and FCU at the 50th and 90th % APDF, whereas the mean activity level of the FCR increased by the 50th and 90th % APDF so that there was no difference at either time between EDC and FCR activation levels (Figure 6). 

Figure 6. Muscle activation of extensors and flexors at the 10th, 50th, and 90th percentile APDF, expressed as a percentage of the maximum voluntary contraction (%MVC) for that muscle.

EDC: extensor digitorum communis, FCU: flexor carpi ulnaris, FCR: flexor carpi radialis. 
* significant difference between mean activation levels.

The unexpected diversity of grasp styles and small number of participants using each grasp prevented adequate comparisons of muscle activation patterns between grasps.

Postural comparisons

RULA assessments produced scores of 3 or 4 in all subjects, indicating that overall postural scores did not differ substantially between subjects, and that all fell into the moderate risk category. Variations in the degrees forearm pronation and supination were noted between subjects, with a range of 80 to 180 degrees of rotation (M= 125, SD = 26.5). The degree of rotation did not appear to be related to the instrument grasp, and was positively correlated with the total pain score determined on the CMDQ and CHDQ questionnaires (r (12)= 0.556, p= 0.039).

Discussion

There has been little previous research into the physical demands of high volume spay neuter surgery. A previous study of MSD prevalence in spay neuter veterinarians (White, 2013) found a 99.1% one-month period prevalence of MSD, which is slightly higher than the 92.9% one-week period prevalence reported in the current study. The body sites with the highest prevalence of MSD were the same in the two studies, with participants most often reporting body MSD in the lower back, shoulders and neck, and hand MSD in the right distal thumb and in the right thumb base. The previous study demonstrated increased MSD risk with increased weekly surgery hours and increased years of work, an effect not seen in the current study. However, these factors had weak explanatory power, accounting for less than 5% of the variability in MSD scores. This small effect size, paired with the smaller sample size in the current study, may account for this lack of effect. Neither study showed an effect of gender on MSD prevalence.

The EMG findings of greater static load on extensors compared to flexors is likely due to the extension of the metacarpophalangeal joints required to execute any of the needle holder grasps. During median and high load conditions, greater need for wrist flexion increases flexor load. Some of the increase with load in the FCR readings may also be due to crosstalk with the superficial digital flexor (Criswell, 2011), and may be related to creating a tighter instrument grasp as greater force is required.

The amount of grasp diversity between participants, the use of non-standard instrument grasps, and the variability in individual participants’ grasps, were surprising findings in the current study. Participants were often unaware of the grasp that they used. Several described themselves using a grasp different from the one that they actually used, and some noticed in the midst of the experiment that they were using a different grasp from what they had described. Even within a single grasp type, the participants varied in their movement patterns and degrees of forearm rotation and wrist angulation. 

Most of the participants claimed to have used their current instrument grasp beginning in veterinary school. However, the wide diversity of grasps, and the use of grasps not described in most veterinary or surgical texts, suggests either that the participants modified their grasps after leaving school, or that their veterinary surgical instructors taught or at least tolerated unconventional grasps. It is also possible that participants’ initial surgery instruction in veterinary school taught conventional instrument grasps, but that later in the curriculum, instructors failed to notice or failed to correct unusual grasps.

After leaving veterinary school, few practitioners receive instruction in instrument grasp or the biomechanics of surgical technique. Veterinary continuing education in surgery emphasizes processes at the “sharp” end of the instrument — the interface between instrument and patient tissue — but generally does not address the interaction between surgeon and instrument. Thus, practitioners are typically on their own as they develop and encode the motor sequences that comprise their practice of surgery. 

The process of acquisition of a motor skill such as suturing requires initial cognitive attention to the task and its components. After repetition, performance becomes smoother and the need to concentrate on the task decreases. Finally, the motor sequence becomes automated and the skilled performer loses conscious awareness of individual motor actions (Ericsson, 2004). This automation of learned action sequences into performance units occurs slowly through repetition without requiring conscious awareness (Graybiel, 1998). 

Surgeons and their patients benefit from the surgeon’s use of automated motor sequences. Automaticity allows the surgeon to execute complex motor sequences with relatively little cognitive load, freeing up cognitive space to attend to other aspects of surgical performance and optimal patient care. However, while beneficial, automated motor sequences may be difficult for skilled performers to describe or teach to others, to modify, or to break down into component parts (Hamdorf & Hall, 2000). In the case of veterinarians, much of this automation is likely to occur after formal surgical instruction has ceased. Thus, the grasp and movement patterns they ultimately adopt may be based on trial-and-error modifications to the techniques they were originally taught. The resulting variations in technique may be adaptive and beneficial, or they may be adequate but sub-optimal solutions in terms of biomechanics or performance (Bartlett et al., 2007).

In addition to diversity of grasps between surgeons, this study also noted instances of variability within individual surgeons’ grasps and movement patterns. In some cases, skilled performers show more variability than novices in the movements that they use to complete a task (Madeleine, 2010; Madeleine et al., 2008). This may be due to flexibility built into the automated motor sequence that they have acquired, or due to the acquisition of more than one automated motor sequence that can be used to complete the same task. For those with flexibility in their automated motor sequence, it is thought that this variability is made possible by the redundant degrees of freedom available in multi-joint movements (Srinivasan & Mathiassen, 2012). This flexibility allows the performer to adapt to perturbations and uncertainty while still completing the task (Bartlett et al., 2007). 

Some skilled performers possess more than one automated movement sequence to perform the same task, and have developed these redundant motor sequences through deliberate practice and refinement (Ericsson, 2004). Among participants in the current study, three reported modifying their grasp after completing veterinary school. Two of these reported making these modifications consciously, and both sometimes use palm grasp and sometimes use 1,4 tripod grasp, selecting their grasp based on ease, comfort, and the appropriateness of the grasp to the specific suturing task. 

It is likely that there is no single, unique movement pattern that optimizes performance (Bartlett et al., 2007). All of the veterinarians in the current study are experienced in high volume spay and neuter surgery, and each has performed thousands of procedures. The diversity in grasps, movement patterns, and muscle use described in this study all represent functional variations upon the task of suturing. Nonetheless, surgeons may benefit from developing multiple functional movement patterns that can be used to achieve the same task, both because this flexibility may lead to improved surgical performance, and because the increased variability may decrease repetitive strain. 

Differences between individuals performing the same task make it difficult to characterize biomechanical exposure and consequent risk based on job description or work hours, and also suggest a possible mechanism for the differences between individuals in MSD susceptibility (Srinivasan & Mathiassen, 2012). The current study did not evaluate variability per se, and only examined a single task within the larger task of surgery, so was not adequate to see the scope of variability within spay neuter work. Future research could examine whether increased motor variability in surgery can be taught, and if so, the optimal amount and type of variability. Also, future studies could examine whether teaching a new grasp and motor sequence could allow a surgeon to recover from MSD, and whether surgeons with more than one grasp and corresponding automated motor sequence are more resilient than those with a single movement pattern.

Conclusions

The present study found an unexpected diversity of needle holder grasps used by spay neuter veterinarians while suturing. All were characterized by extensor dominance during static load. Future investigation into the characteristics and benefits of various grasps is warranted, so that practical advice on reducing strain and MSD risk can be offered to surgeons. In addition, examination of current surgical instruction and learning may help explain the origination of the diversity of grasps encountered here.

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Weiss, Y. (1973). Simplified method of needle-holder handling. Archives of Surgery, 106(5), 735-736. 

White, S. (2013). Prevalence and risk factors associated with musculoskeletal discomfort in spay and neuter veterinarians. Animals, 3(1), 85-108. 

Yoon, H.-Y., & Mann, F.A. (2011). Instrument handling. In F. A. Mann, G. M. Constantinescu & H.-Y. Yoon (Eds.), Fundamentals of small animal surgery (pp. 128-142).

Pool Shock at the clinic? Yes– here’s why

This post goes along with the JIFFI post about surgical hand hygiene from last year, since it’s about a low-cost way of keeping the surgical environment clean. For a lot of people, this will be old news, but for anyone who hasn’t used calcium hypochlorite to disinfect in their clinic, or who is wondering about the research behind this disinfectant and its preparation, read on–

Origin story

Back in the fall of 2010, in the days of Trifectant, before accelerated hydrogen peroxide took the shelter disinfection world by storm, my friend Brenda was raving about a kennel cleaner called Wysiwash. The active ingredient is calcium hypochlorite, and the product is sold as a hose-end sprayer for kennel disinfection. There was a lot to be excited about: it’s cheap and effective against most of the pathogens we’re worried about in veterinary care, it’s much less irritating than bleach, and it doesn’t need to be rinsed away.

But I have a MASH mobile spay neuter clinic: I don’t have kennels or a hose, and I only need a gallon or two of disinfectant every day. How could I use this product? Sure, I could put a hose-end sprayer on a hose at home and fill a jug, but how would that work in the winter when the hoses are frozen solid? I decided there had to be some other way to purchase and mix calcium hypochlorite.

Researching an alternative

After spending some time on Google, I found that one of the most easily available forms of calcium hypochlorite is swimming pool shock. But how much to use? And which type?

Fortunately, Wysiwash and many of the pool shock suppliers also provided online copies of MSDS (now SDS) sheets listing the chemical composition of each product. After downloading a bunch of these MSDS sheets, I was able to find Turbo Shock, a pool shock product with the same chemical composition– the same components, in the same proportions– as Wysiwash. Turbo Shock is supplied as a white granular powder and can be purchased in a 1-pound bag.

Next I had to figure out how much to use. For that, I turned to the technical information page on the Wysiwash site and found this paper describing how to make a 2x solution of Wysiwash in the lab. Armed with that information and the density of the pool shock (also from the MSDS), I was able to make the calculation that you would need just over 1/16 teaspoon of Turbo Shock per gallon of water to make the same strength solution as the hose-end sprayer. For practical reasons (the smallest plastic measuring spoon I can find is 1/8 tsp, and metal measuring spoons rust almost immediately when used in pool shock), I end up using a 2x concentration, mixing 1/8 tsp per gallon. At this rate, it takes me a few years to go through just one bag of Turbo Shock.

I started using this solution that fall, and by spring of 2011, I mentioned Turbo Shock using in a conference presentation at the SNIP Summit in Asheville. After that presentation, other spay neuter and shelter vets have started using calcium hypochlorite solution made from pool shock, especially for disinfecting endotracheal tubes, masks, and pulse oximeter probes between patients, and in some cases for disinfecting animal contact surfaces such as scales and tables.

But wait…!

So I know what y’all are thinking: “What about that 2015 article by Dr. Karen Moriello showing that calcium hypochlorite was ineffective against ringworm?” I read this one too, but I’m not quite ready to throw the baby out with the pool water.

In this study, in order to obtain the calcium hypochlorite solution, a Wysiwash hose-end sprayer was used and the solution was collected midstream after the hose had run for 3 minutes. One of the downsides of a hose-end sprayer is that you have to take it on faith that the correct amount of disinfectant is being dispensed at any given moment. This made me wonder– what if the solution that was being dispensed from that hose was not as concentrated as it should have been? What if there was something wrong with the sprayer and there wasn’t any calcium hypochlorite in it at all? The strengths of the various solutions used in the study were never verified; for the study design, this was appropriate (after all, she was using kennel disinfectants according to label and assessing their effectiveness), but it doesn’t tell me for sure that a solution of calcium hypochlorite is ineffective against ringworm fungus.

So if any of you who are reading this are students, interns, or residents and you’re looking for a project, I would love to see the calcium hypochlorite portion of this study replicated with a known or verified concentration of the chemical. This could be done by testing the chlorine content of the solution, which should be between 60-70 ppm for a 1x solution or about 120 ppm for a 2x solution, and could be tested with commercial chlorine test strips. Why not test both strengths and let us all know how it turns out?

Pro tips

As I mentioned above, calcium hypochlorite powder can corrode metal when in prolonged contact (I have had no problem with the mixed solution causing damage when disinfecting metal surfaces, though). Avoid using a metal measuring spoon. I’ve also been told that one clinic that stored a bag of pool shock under their sink found that just the fumes from the bag of pool shock corroded the metal pipes under the sink– so be careful and store away from metal. Plastic measuring spoons and plastic storage containers seem to hold up well.

Since it takes me a long time (years) to go through a 1-pound bag of Turbo Shock, I dispense the powder into a labeled pill vial to carry with me to clinics. I re-seal the pool shock bag by rolling down the edge and using a rubber band to secure it (the metal clip in the photo attached to this blog post? Completely rusted now).

It’s also probably obvious (if you think about swimming pools, or chlorine bleach), but calcium hypochlorite is not a detergent or a cleaner: it’s a disinfectant, but it won’t do any more than water would do to clean slimy, messy, dirty objects. For anything that’s dirty, slimy, etc (including endotracheal tubes), clean first (soap and water!), then disinfect.

Surgery Packs and Suture in HQHVSN

Today’s post is a little different: I’m sharing the results of a survey of HQHVSN veterinarians and their choices in instrumentation and suture for spay and neuter surgeries.

Instruments and suture are the interface between us and our patients, and are integral to every aspect of our surgical performance: our efficiency, our comfort, and our precision. While I know of other authors who have speculated on the “typical” spay pack or neuter pack in private practice or in HQHVSN, I didn’t know of any study of what is actually used out there in practice. So, I designed a study and am publishing it here.

Methods

An 8-question multiple choice and matrix-type question survey was designed in Survey Monkey. The first 3 questions included separate answer grids for numbers and types of instruments and drapes in dog spay, dog neuter, and cat spay packs. Respondents were then asked about usage of suture cassettes versus suture with needles attached (swaged-on), suture type preferences, and finally suture size preferences for different surgery types and patient sizes.

A link to the survey was distributed to the HQHVSNvets Yahoo Group and was posted on the Association of Shelter Veterinarians Facebook group. Reminders were distributed on 5/1/18. Responses were collected from 4/26/18 to 5/9/18, and results were downloaded into Microsoft Excel for analysis.

Results

There were 83 completed responses to this survey. Of those, one veterinarian performed only cat surgeries, whereas the other 82 performed cat and dog surgeries.

Surgery Packs

Of the 82 veterinarians working with cats and dogs, 12 (14.6%) had only one type of surgery pack that they would use for any of the different surgeries. In addition, there were others who used the same pack type for multiple types of surgeries, but not for all surgery types. Six (7.3%) used the same type of packs for cat spays and dog neuters, but different pack types for dog spays. Two (2.4%) used the same types of packs for dog spays and neuters, but a different type of packs for cat spays.

Dog spay packs

See a PDF version of the dog spay packs graph

There were a median of 11 instruments in each dog spay pack, with a range from 6 to 18. All dog spay packs contained a spay hook, a thumb forcep, scissors, and a needle holder. Of the needle holders, 79 (96.3%) were Olsen Hegar and only 3 (3.7%) were Mayo Hegar. Of the scissors, 39 packs (47.6%) had Mayo scissors, 62 (75.6%) had Metzenbaum scissors, and 3 (3.7%) had Operating scissors. Twenty-one dog spay packs (25.6%) contained both Mayo and Metzenbaum scissors. Of the thumb forceps, 70 dog spay packs (85.3%) contained Adson Brown forceps, 16 (19.5%) contained rats tooth forceps, and 8 (9.7%) contained Adson tissue forceps. Some packs contained more than one thumb forcep. One respondent commented that they used whichever thumb forcep type had been donated.

The packs with only 6 instruments did not contain any hemostats; all other dog spay packs (98.7%) contained at least one type of hemostat. Seventy-five (91.4%) contained Kelly or Crile type hemostats (1-5 per pack), 68 (82.9%) contained Carmalts (1-4 per pack), and 63 (76.8%) contained mosquito hemostats (1-4 per pack). Some respondents commented that additional instruments including Carmalts or Rochester Pean forceps were available in separately wrapped packages for use as needed on dog spays.

Additional instruments included in dog spay packs were towel clamps in 49 packs (59.8%), with 1-4 towel clamps present per pack, and scalpel blade holders in 32 packs (39.0%). One respondents’ dog spay packs included a Dowling Spay Retractor, and two included Allis Tissue Forceps.

Seventy-five packs (91.4%) contained drapes of some type, with 51 (62.2%) containing cloth drape and 27 (32.9%) containing paper drape (of these, 3 contained both paper and cloth drape). Some respondents also commented that their packs contained huck towels. One respondent commented that drapes are wrapped separately; this is likely to be the case for all clinics where drapes are not included in the packs. 52.9% of the packs containing cloth drapes also contained towel clamps, whereas 70.4% of the packs containing paper drapes also contained towel clamps.

Cat Spay Packs

See a PDF version of the cat spay pack graph

There were a median of 10 instruments in each cat spay pack, with a range from 6 to 15. All cat spay packs contained a spay hook, a thumb forcep, and a needle holder. Of the needle holders, 79 (95.2%) were Olsen Hegar and only 4 (4.8%) were Mayo Hegar. Of the thumb forceps, 70 cat spay packs (84.3%) contained Adson Brown forceps, 13 (15.6%) contained rats tooth forceps, and 8 (9.6%) contained Adson tissue forceps. Some packs contained more than one thumb forcep.

Of the scissors, 28 packs (33.7%) had Mayo scissors, 62 (74.7%) had Metzenbaum scissors, and 5 (6.0%) had Operating scissors. Thirteen cat spay packs (15.6%) contained both Mayo and Metzenbaum scissors, and two packs (2.4%) did not contain scissors.

The packs with only 6 instruments did not contain any hemostats; all other dog spay packs (98.7%) contained at least one type of hemostat. Seventy-seven (92.8%) contained mosquito hemostats (1-4 per pack), 67 (80.7%) contained Kelly or Crile type hemostats (1-3 per pack), and 40 (48.2%) contained Carmalts (1-3 per pack). One contained two Rochester Pean forceps.

Additional instruments included in cat spay packs were towel clamps in 42 packs (50.6%), with 1-4 towel clamps present per pack, and scalpel blade holders in 31 packs (37.3%).

Seventy-nine packs (95.2%) contained drapes of some type, with 51 (61.4%) containing cloth drape and 29 (34.9%) containing paper drape (of these, 3 contained both paper and cloth drape). Some respondents also commented that their packs contained huck towels. One respondent commented that drapes are wrapped separately; this is likely to be the case for all clinics where drapes are not included in the packs. 45.1% of the packs containing cloth drapes also contained towel clamps, whereas 58.6% of the packs containing paper drapes also contained towel clamps.

Dog neuter packs

See a PDF version of the dog neuter pack graph

There were a median of 8 instruments in each dog neuter pack, with a range from 1 to 15. No instrument type was present in every dog neuter pack, although all but one contained at least one hemostat. Two dog neuter packs (2.5%) consisted of only one mosquito hemostat. Sixty (74.1%) (including the two above) contained mosquito hemostats (1-4 per pack), 60 (74.1%) contained Kelly or Crile type hemostats (1-3 per pack), and 34 (42.0%) contained Carmalts (1-2 per pack).

Seventy-eight of 81 dog neuter packs contained needle holders: 74 (91.4% of packs) contained Olsen Hegar and only 4 (4.9%) contained Mayo Hegar. All packs except the single hemostat packs contained thumb forceps; 68 (84.0%) contained Adson Brown forceps, 9 (11.1%) contained rats tooth forceps, and 5 (6.2%) contained Adson tissue forceps. Some packs contained more than one thumb forcep.

Fifty-seven (70.4%) dog neuter packs contained scissors: 28 (34.6%) had Mayo scissors, 38 (46.9%) had Metzenbaum scissors, and 3 (3.7%) had Operating scissors. Twelve dog neuter packs (14.8%) contained both Mayo and Metzenbaum scissors, and 24 packs (29.6%) did not contain scissors.

Additional instruments included in dog neuter packs were towel clamps in 39 packs (48.1%), with 1-4 towel clamps present per pack, and scalpel blade holders in 26 packs (32.1%). Twenty-one (28.4%) dog neuter packs contained a spay hook, likely because these packs were not assembled specifically for dog neuters.

Seventy-two packs (88.9%) contained drapes of some type, with 48 (59.3%) containing cloth drape and 26 (32.1%) containing paper drape (of these, 2 contained both paper and cloth drape). Some respondents also commented that their packs contained huck towels. 41.7% of the packs containing cloth drapes also contained towel clamps, whereas 57.7% of the packs containing paper drapes also contained towel clamps.

Suture
Suture type and packaging

Eighty-two veterinarians responded to the question regarding the suture packaging that they used most commonly. Over half of respondents used swaged-on suture all the time or most often, although 42% used suture from a cassette all or most of the time.

“Other” responses included “Cassette for internal ligatures and large spay closures. Swaged on for small spay closures” and “Swaged on when I need a needle, I use Cassette suture to ligate the pedicles and uterine stump”

Suture composition

Eighty-one veterinarians responded to the question about what suture composition they used for each surgery. Veterinarians showed a strong preference for synthetic monofilament suture for all surgery types, with all but one respondent (98.8%) using this suture type for at least some surgeries, and 75 respondents (92.6%) using only synthetic monofilament suture in all surgeries.

The one surgeon who did not use any synthetic monofilament suture used synthetic braided suture in all surgery types.

Two surgeons (2.5%) used stainless steel in cat spays; both of these veterinarians also used synthetic monofilament suture in cat spays, and one also indicated that they use chromic gut in cat spays. This surgeon commented that they used stainless steel for uterine body ligation in pediatric kittens.

Three surgeons used chromic gut suture in at least some surgeries. All three used chromic gut in dog spays; 2 used it in dog neuters, and one used it in cat spays. In all cases, veterinarians who used chromic gut in a surgery type also used synthetic monofilament suture in that surgery type. One of the surgeons who uses chromic gut in dog spays commented that they “ligate pedicles with 2 chromic gut for most dogs >40# (great knot security),” but close the abdomen with synthetic monofilament suture.

No surgeons used synthetic nonabsorbable suture in any surgery type in this survey.

Suture size

Eighty two surgeons responded to questions about their suture size preferences. For kitten spays, 33 (40.2%) used 4-0 suture while 55 (67.1%) used 3-0 suture. Some surgeons responded with both suture sizes for kittens. For adult cats, only 3 (3.7%) surgeons used 4-0 suture while 76 (92.7%) used 3-0 suture, 13 (15.9%) used 2-0 suture, and 3 (3.7%) used 0 suture. Some surgeons responded with more than one suture size for adult cat spays. Some surgeons commented that they used the larger sizes of suture specifically for uterine body ligation in the pregnant, enlarged, or diseased uterus, and smaller suture for body wall and subcutaneous closure.

In dogs, suture size preferences were more variable. For the smallest puppy spays under 10 pounds, 3-0 was preferred by 80.5% of respondents. For puppies 10-20 pounds, respondents were nearly evenly split between 3-0 and 2-0 suture. By the time puppies were over 30 pounds, 2-0 suture was preferred by most veterinarians.

See a PDF version of Puppy spay suture size with percentage values

For adult dog spays, suture size preferences also varied considerably, with 3-0 preferred for the smallest dogs under 10 pounds, 2-0 for those 10-40 pounds, 2-0 and 0 nearly equally selected for 40-50 pound dogs, and 0 preferred for those over 50 pounds. Some surgeons commented that they used more than one size of suture in larger dogs, with a large size suture used for ligations and body wall closure, and smaller suture selected for the subcutaneous and subcuticular closures. This accounts for the persistence of small suture sizes even in the largest dog spays.

See a PDF version of Dog spay suture size with percentage values

Adult dog neuter suture size preferences were somewhat smaller than those preferred for spays. For dogs under 20 pounds, 3-0 was preferred, with 2-0 for those 20-50 pounds, 2-0 and 0 nearly equally selected for 50 pounds and up.  Some surgeons commented that they used more than one size of suture in larger dogs, with a large size suture used for cord ligations, and smaller suture selected for the subcutaneous and/ or subcuticular closures and for ligation of subcutaneous bleeders. This accounts for the persistence of small suture sizes even in the largest dog neuters.

 

See a PDF version of Dog neuter suture size with percentage values

Not all veterinarians use suture on adult dog neuters. One respondent commented, “Rarely use suture, autoligate most cords and glue the scrotum. Only do ligatures on very large cords, only suture very pendulous scrotums.”

Discussion

Instrument preferences

Certain instrument preferences are identifiable within this data. A large majority of veterinarians chose Olsen Hegar¹  needle holders over Mayo Hegars. Olsen Hegars allow increased efficiency by allowing the surgeon to cut suture ends after knot tying without requiring them to exchange needle holders for scissors. While there is some risk with Olsen Hegar needle holders of inadvertently cutting suture while attempting to grasp, this consequence may be reduced with attention and practice. In addition, since spay and neuter surgeries do not require suturing in deep cavities, it is less likely that suture will be inadvertently cut, as this occurs most often when visibility is poor and when suturing in a restricted space.

Fewer than half of the surgery packs contained scalpel blade handles. While it has been suggested that use of blades on scalpel handles is safer than using unattached blades, other literature suggests that about 10% of scalpel injuries occur during disassembly of the blade from the handle. Spay neuter veterinarians may choose to eliminate scalpel handles from their packs due to the additional time required to assemble and disassemble the blade and handle, and the ability to make smaller and quicker movements with the blade alone than with the blade with handle. Disadvantages of using unattached scalpel blades could include the increased likelihood of losing track of the blade within the surgery field and potential injury due to lack of visualization of the blade, or due to the blade slipping in the fingers.

Towel clamps were present in about half of the packs, and were more likely to appear in dog spay packs than in other packs. In all surgery pack types, towel clamps were more likely to be included in packs with paper drapes compared to cloth drapes. This suggests that the draping qualities of cloth drapes allow these drapes to remain in place more readily without clamping, whereas the stiffer, less-conforming nature of paper drapes means that veterinarians are more likely to choose to use towel clamps. In addition, some veterinarians or clinics may choose not to use towel clamps on cloth drapes in order to avoid damaging the reusable cloth and shortening the life of the drape material.

Surgery pack sizes and contents varied considerably. For clinics with many surgery packs, the expense of purchasing larger packs and the labor required to reprocess the larger number of instruments could both be substantial. For clinics purchasing or assembling new packs, it might be worth considering assembling smaller packs and providing separately wrapped and sterilized additional instruments for use when needed, rather than including greater numbers of instruments in each pack.

Sutures

The use of cassette suture by nearly half of the respondents may have been a nod to economy, but also would have facilitated the use of different suture sizes in different parts of the surgery or different layers of the closure. Surgeons may be hesitant to open a new package of suture simply to place one or two ligatures or appositional sutures, but may be more willing to do so when a small amount of suture can be removed from a cassette for that purpose. The respondents who use both cassette and swaged-on suture may also be taking advantage of this multi-size strategy by using cassette suture for ligations, where no needle is needed, and swaged suture for locations where suturing with a needle is required.

Suture type selection was unsurprising, with most respondents preferring synthetic monofilament absorbable suture throughout their surgeries. Since no surgeons indicated the use of nonabsorbable synthetic suture, it can be inferred that none are placing external skin sutures in their spay and neuter patients. This may be different from the private practice setting, where patients may be expected to return to the veterinary clinic for skin suture removal, a practice which may be impractical or impossible in the HQHVSN setting.

Limitations

This survey only asked about instrument and suture preferences. While it is possible to make some inferences about technique from the choices of instrument and suture and from comments left by respondents, it is not truly possible to know from these questions what techniques HQHVSN vets are actually using. This information would be interesting but was beyond the scope of this study.

The survey respondents were self-selected and consisted of veterinarians who use electronic means (Yahoo group or Facebook group) to connect with other veterinarians in shelter or spay neuter practice. These veterinarians may or may not be typical of veterinarians in these types of practice– thus, the results may not be reflective or representative of all spay neuter practice. Furthermore, responding veterinarians may be using packs and suture types which have been selected by others (practice managers, previous veterinarians) and which do not necessarily reflect their own preferences.

Conclusion

Surgical instruments and suture are an important factor in the physical ergonomics of surgery and represent the interface between veterinarian and patient. Selection of these tools will affect the efficiency, comfort, and performance of the surgeons who use them.  This survey demonstrated some areas of consistency among surgeons, as well as substantial variability in other areas, but I hope that at least some clinics and veterinarians find this information useful.

Footnote

  1. Bushby calls the Olsen Hegar needle holder a “spork.” I think this is really funny and accurate, despite my love for my Olsen Hegars.

Spay-Neuter Guidelines: New and Improved!

This week, The Association of Shelter Veterinarians’ 2016 Veterinary Medical Care Guidelines for Spay-Neuter Programs was published in the Journal of the American Veterinary Medical Association. With this new publication, the 2008 Guidelines have been updated to reflect findings from new research as well as to integrate research and ideas from beyond the traditional confines of the veterinary field into recommendations for spay-neuter practice.

Why am I so excited about this publication? Not just because I had the honor to work on its creation with a brilliant and kind group of veterinarians who passionately believe in elevating spay neuter practice. Not just because of the thoroughness of the research that went into this update, and the hours of work this entailed.

I am excited because this is the first time I have ever seen a veterinary practice guideline that takes a deep and practical view of operations management. By devoting nearly 2 full pages to human factors and ergonomics, the 2016 Guidelines acknowledges the central role that humans play in veterinary practice—that is, human bodies, human cognitions, human emotions, and human behaviors. The addition of this new section demonstrates a recognition that safe performance relies on close evaluation of procedures, and on redundant systems that can handle the unexpected. High quality, high volume spay neuter practices can strive to become high reliability organizations by exploring and implementing the ideas in the operations management section of the 2016 Guidelines.

The operations management section in the 2016 Guidelines shows that spay neuter practice— and indeed all veterinary practice— is an integrated system in which performance of each part affects the others.  The 2016 Guidelines makes the connection between leadership style, work satisfaction, and musculoskeletal discomfort. Between process management and safe practice. Between ergonomics and performance. Between safety and leadership. And by making these connections, the 2016 Guidelines give practitioners the tools to accomplish continuous improvement in their workplace.

I’m also excited because the 2016 Guidelines is the first veterinary practice guideline that includes specific ideas in physical ergonomics, rather than simply stating that ergonomics is important in surgery (leaving the practitioner on their own to discover or research ergonomic solutions, or, more likely, to discover the scarcity of accessible ergonomics publications for veterinary practice). Musculoskeletal discomfort limits the practices of many veterinarians, but its causes and mitigation are rarely addressed in veterinary publications. It’s time that we recognize that our bodies and our minds are the most valuable pieces of veterinary equipment we have. That we need to learn, and to teach each other how to protect against wear and tear, and to alleviate the physical and mental stresses that accumulate. And that physical and mental discomfort are, after all, closely linked, so that making improvements in one is bound to improve the other.

In short, the 2016 Guidelines are a great reference for anyone working in veterinary medicine, and especially helpful for anyone working in spay neuter or shelter practice.

Want to learn more about human error and safety in complex systems? Here are some interesting books (also, explore other works by these authors):

The Human Contribution: Unsafe Acts, Accidents and Heroic Recoveries by James Reason

The Checklist Manifesto: How to Get Things Right by Atul Gawande

Wellness and Complications

5/14/16 Edit:  This post is two parts: mental health statistics in veterinarians, and veterinarians’ experience of adverse events.  My  writing about the stress and distress that can surround complications isn’t meant to imply that complications are the cause of veterinarian suicide, but rather that they are a predictable, and predictably stressful event that veterinarians encounter and that we aren’t generally taught how to handle. For some people, these events contribute to the anxiety, depression, and self-doubt that may also be impacting their overall mental health, and for some people, adverse events are a reason to leave the field or the profession.

Veterinarian wellness and mental health have received an increasing amount of attention recently within the profession. Veterinarians overall appear to be no more at risk for mental illness than those in the general population, but certain subgroups of veterinarians—young, female veterinarians, and those who work alone rather than with others—are at higher risk than other veterinarians for suicidal thoughts, mental health difficulties, and stress (Nett et al., 2015; Platt et al., 2012). While there is no published data about mental health specifically in spay/neuter veterinarians, shelter veterinarians do appear to be at higher risk for serious psychological distress (Nett et al., 2015). Further, many shelter and spay/neuter vets are young and female (White, 2013) and work apart from other veterinarians, placing them in a higher risk demographic. The suicide rate published for the veterinary profession is approximately four times that of the general population, and twice that of other health professionals (Bartram & Baldwin, 2010). While no one is certain of the reasons for this, most authors propose that it is due to a combination of personal characteristics, feelings of stress, and having medical knowledge and access to medications.

Any veterinarian who is experiencing anxiety, depression, thoughts of suicide or other mental health problems should seek the care of a health professional. The AVMA is developing wellness tools for veterinarians available here. Other resources that could be useful are Vetlife, a UK resource for veterinarians, and this site hosted by the Washington State Veterinary Medical Association.

Complications and Stress

Performing surgery can be stressful, and events that occur while in surgery can increase the amount of intraoperative stress experienced. Unlike workers in other industries in which the safety of others is at stake, surgeons are not typically trained in stress-management or how to mitigate the effects of stress on surgical performance (Arora et al., 2010). In the past few years, there has been some research on human healthcare providers, including surgeons, and their reactions to and thoughts about adverse events (see an article by Luu et al here and a book by Sidney Dekker here), but I couldn’t find any research specifically looking into veterinarians and our reactions to adverse events and how we cope with them.

So, I’m currently conducting a research study on spay/neuter veterinarians and adverse events. The purpose of this research is to explore the experiences and reactions of spay/neuter vets after serious adverse patient events (serious, life-threatening complications or death) related to spay/neuter. I am interested in the ways that veterinarians react to these events, the ways that we talk about them, think about them, and cope with them. My hope is that this research will give us tools to support each other, our clinic or shelter staff, and ourselves as we deal with adverse events. Understanding as much as we can about how spay neuter veterinarians react to and process adverse events could be a vital piece of making continuous improvements in the care that we provide. I’ll share results here on this website, as well as any information about presentation or publication of the results as they are available.

Meanwhile, here are some thoughts on dealing with complications from the existing literature on human practitioners:

All veterinary practices experience perioperative complications and deaths. In high volume spay/neuter, the high volume of surgeries performed means that, even in clinics with exceptionally low mortality rates, some perioperative deaths will occur. Perioperative deaths can lead to feelings of guilt, responsibility, and self-blame, as well as grief and sadness (Luu, Leung, & Moulton, 2012; Luu, Patel, et al., 2012). When a patient death occurs, fear, grief, or self-doubt can make it difficult to continue with the day’s scheduled surgeries, but the schedule of many spay/neuter and shelter clinics makes it difficult or impossible to interrupt the work schedule for debriefing and time away.

Candid discussion of deaths, errors, mistakes, and mishaps can be taboo in medicine: surgeons often have the expectation that they should perform flawlessly (Wu, 2000). In spay/neuter practice, there appears to be more open discussion of complications and near misses than in many medical fields; however, spay/neuter veterinarians may still benefit from increased discussion of early recognition of danger, errors, decision-making, expertise, and error-recovery (Patel et al., 2011). For those who work in facilities without access to peers, electronic listserves are a resource to allow communication with other spay/neuter surgeons. Spay/neuter veterinarians may also benefit from training in the skills needed for performance while under stress.

 

References:

Arora, S., Sevdalis, N., Nestel, D., Woloshynowych, M., Darzi, A., & Kneebone, R. (2010). The impact of stress on surgical performance: A systematic review of the literature. Surgery, 147(3), 318-330, 330 e311-316. doi: 10.1016/j.surg.2009.10.007

Bartram, D.J., & Baldwin, D.S. (2010). Veterinary surgeons and suicide: A structured review of possible influences on increased risk. Vet Rec, 166(13), 388-397. doi: 10.1136/vr.b4794

Luu, S., Leung, S.O., & Moulton, C.A. (2012). When bad things happen to good surgeons: Reactions to adverse events. Surg Clin North Am, 92(1), 153-161. doi: 10.1016/j.suc.2011.12.002

Luu, S., Patel, P., St-Martin, L., Leung, A.S.O., Regehr, G., Murnaghan, M.L., Gallinger, S., & Moulton, C.-a. (2012). Waking up the next morning: Surgeons’ emotional reactions to adverse events. Medical Education, 46(12), 1179-1188. doi: 10.1111/medu.12058

Nett, R.J., Witte, T.K., Holzbauer, S.M., Elchos, B.L., Campagnolo, E.R., Musgrave, K.J., Carter, K.K., Kurkjian, K.M., Vanicek, C.F., O’Leary, D.R., Pride, K.R., & Funk, R.H. (2015). Risk factors for suicide, attitudes toward mental illness, and practice-related stressors among us veterinarians. Journal of the American Veterinary Medical Association, 247(8), 945-955. doi: 10.2460/javma.247.8.945

Patel, V.L., Cohen, T., Murarka, T., Olsen, J., Kagita, S., Myneni, S., Buchman, T., & Ghaemmaghami, V. (2011). Recovery at the edge of error: Debunking the myth of the infallible expert. J Biomed Inform, 44(3), 413-424. doi: 10.1016/j.jbi.2010.09.005

Platt, B., Hawton, K., Simkin, S., & Mellanby, R.J. (2012). Suicidal behaviour and psychosocial problems in veterinary surgeons: A systematic review. Soc Psychiatry Psychiatr Epidemiol, 47(2), 223-240. doi: 10.1007/s00127-010-0328-6

White, S. (2013). Prevalence and risk factors associated with musculoskeletal discomfort in spay and neuter veterinarians. Animals, 3(1), 85-108.

Wu, A.W. (2000). Medical error: The second victim: The doctor who makes the mistake needs help too. BMJ: British Medical Journal, 320(7237), 726.

 

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.

surgeon neck angleIt 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.

becky twisted either wayHowever, 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.

surgeon stretch

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: Instruments and Needles

How much force does it take to close and open the ratchet on your needle holders and hemostats? Do you have certain instruments that are more stiff or require more force?

It should not take a lot of force to open and close the ratchets on most surgical instruments. Over the course of a surgery day, repeatedly having to apply extra force due to stiff instruments can add to the trauma on the surgeon’s body.

There aren’t many studies or other publications on the subject; one that I have found is an article by a South Australian surgeon, Michael Patkin.

Patkin M. Surgical instruments and effort referring especially to ratchets and needle sharpness. The Medical Journal of Australia 1970;1:225.

Patkin has an interesting website as well with plenty of thoughts and observations on human surgery and ergonomics.

There is not (at least that I am aware) any standard for optimal force required to open or close instruments, but based on my reading of Patkin and my own experience in surgery, I suggest aiming for about 3 pounds of force to close the first ratchet, and about 1 pound of lateral force to open the ratchet.

 

needle holder on scale
My favorite needle holders coming in at 2 pounds 14 ounces to close the ratchet. Do you need to go to the trouble to test your own instruments? Probably not, unless you’re curious or just nerdy.

Thumb forceps can also be stiff and difficult to operate. Often, the larger thumb forceps are stiffer than the smaller Adsons or Adson-Browns.  If you are experiencing difficulty with your non-dominant, thumb forcep hand, consider choosing a smaller thumb forcep that closes with less pinch force.

In order to reduce the force required by instruments and needle holders, try the following:

  • Make sure that you are using good protocols for cleaning and processing
  • Get scissors and needle holders sharpened and get jaws replaced when they get dull or smooth.
  • Discard needles when they are dull.  It takes extra force to penetrate the tissue with a dull needle, and causes extra tissue trauma for the patient.
  • If you have the chance to make purchasing decisions, choose instruments that don’t require a lot of force to open and close.

Your hands and the patient’s tissues will thank you!

 

Surgical Ergonomics: Performing surgery

Spay neuter surgery involves a combination of repetitive movements that can at times require force, or may be performed with awkward positioning of the hands and wrists. Each of these factors alone is only moderately associated with pain, but put together there is a strong association with hand and wrist pain.

In any high volume workplace, there will be repetition; it’s unavoidable. Fortunately, many high-volume surgery techniques can reduce some of the repetition.

For example:

  • Pedicle ties mean fewer suture knots (i.e., less repetition of knot-tying motion)
  • Shorter incisions mean fewer sutures placed, and fewer knots tied
  • Efficient technique in general means less wasted motion

In case you are not familiar with some of these techniques, I have included some links and videos so that you can learn about them.

Pedicle Ties are an autoligation technique used in feline spay surgery on the ovarian pedicles. For a peer-reviewed study on the safety of pedicle ties, see this article by Miller et al. The abstract is available here. Pedicle ties are a safe alternative to the use of sutures for ligation in cats, and can decrease surgery time. And shorter surgery time means less trauma for the cat and for the surgeon.

Here is a video of several pedicle ties:

 

Shorter spay incisions are achieved with practice. The incision needs only to be long enough to deliver the uterus through the opening. Use of a spay hook (on cats and dogs, not other species) is helpful in allowing a smaller incision. It is worth the practice time it takes to be able to make a short incision. As with pedicle ties, short incisions allow for shorter surgery time, less repetition, and less trauma to the animal and the veterinarian.

Here is a video of a cat spay using a short incision and a pedicle tie:

Want to learn more about high volume techniques? Check out Humane Alliance’s E-Learning resources.

So, high volume techniques can decrease the number of repetitions of any given action– but how else can a surgeon lower the risk of hand and wrist pain?

Sustained awkward or tiring positions can lead to discomfort. The pinch grip used for thumb forceps is a common example of an awkward, tiring grip. Some spay neuter vets minimize the use of thumb forceps during closure. This reduces the trauma to skin edges, and also reduces strain from the pinch grip, so it can be a win-win situation.

pinch grip

Other awkward or extreme postures are rarely necessary in spay and neuter surgery, but they may be something that you are using without really realizing it.  This is a great reason to get video of yourself doing surgery.

You can find awkward spay pictures from the internet (see one below) that show a large amount of wrist flexion or extension. These positions are all OK, as long as they are comfortable and not sustained or repeated for a lot of time. If they become uncomfortable, or if the surgeon is spending a lot of time in extreme or awkward positions, then it’s time to think of other ways to perform the same surgical tasks.

Here are some arm positions during suturing that are near the extremes of their ranges of motion. Again, there is nothing inherently wrong with having positions that are at the end of the range of motion. But, if they become uncomfortable or inefficient, or they are sustained or repeated often, then the surgeon will need to try alternative positions to achieve the same tasks.

supinationpronationulnar deviation(These vets have wires and stick-on electrodes on their arms because they were a part of my Masters’ research project).

There are a lot of different ways that spay neuter vets hold their needle holders. Some spay neuter vets swear by using the palm grasp, whereas others have never used it. It turns out that the amount of muscle use and the range of motion is so variable between different vets that I can’t really make generalizations about muscle strain.
tripod grasp

This is another case where photos and video are helpful. If the motions of surgery and grasping instruments are uncomfortable, then that may be a cue for the surgeon to consider learning a different grasp style and seeing if the changes in grasp take strain off the uncomfortable body areas.

There are also times when surgical technique can change your whole body posture. In this illustration, the vet is doing a continuous SQ closure from left to right.  In order to position the needle, she is twisted around, leaning over, and has a raised elbow.

surgeon leaning

And here is me doing the same thing.

Untitled

It wasn’t until I took this video that I realized how awkward this is, and after a little research I realized how easy the solution could be. Just by doing the same closure from right to left, the surgeon can avoid all the twisting and leaning.

better postureThe moral is, if you’re doing something really awkward, there is probably another solution that is a lot smoother and easier.

 

 

 

 

 

 

In addition to repetitive motion and awkward position, forceful motions are the other contributor to hand and wrist pain. The most common times when a spay neuter vet has to use force is during suturing and knot tying, and during castration of large male dogs.

suturingChoosing a suture size that is bigger than what you need for a given surgery means that on every throw of every knot, you will be applying more pounds of force to your ligaments and muscles.  Over the course of a surgery day, that’s hundreds of times that you’re applying that extra force.

So in addition to being good surgical practice to select appropriate suture size, it’s also good ergonomic practice.

 

With the big dog neuter, the spay neuter vet can be using a combination of force and awkward posture to exteriorize the testicle.

As you can see in the illustration, the surgeon has to have a firm grasp and may be pulling with a substantial amount of ulnar deviation– so the wrist is canted towards the pinkie finger. This can be challenging for people with discomfort anywhere in the upper quarter of their body, from hand, wrist, and elbow, to shoulder, neck, and upper back.

dog neuterSome alternatives that decrease this strain could include

  • Open castration
  • Sharply dissecting the fibrous attachments around vaginal tunic and between tunic and subcutaneous tissue
  • Using a hemostat to clamp the cord just proximal to the testis once the spermatic cord is exposed, to provide a more favorable grip for applying traction, rather than grasping the testis itself

dog neuter hemostat

So, as you can see, there are some options for avoiding the three biggest combined risks for hand and wrist pain: repetition, force, and awkward posture. Next post, I’ll talk about instruments and needles.

 

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.