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