Suture material is the most common foreign body intentionally left inside patients. It can delay wound healing, cause infection or create an ugly scar. Choosing which suture type to use should therefore be taken seriously.
In a perfect world, suture material would be strong, easy to handle, non-reactive, non-toxic and affordable. It also would offer good knot security and be reabsorbed by the body at a predictable rate once the tissue has healed.
Courtesy of Dr. Phil Zeltzman
Appropriate suture choice and technique are just the beginning. It is important to use an E-collar to prevent self-trauma, as in this 10-year-old Labrador, who had a hemilaminectomy for a disc hernia.
But the variety of suture materials and needles can be overwhelming. We asked Thomas McMahan, sort of a suture guru, to help us untangle the web of suture materials in an exclusive interview.
Q. What is your background?
A. I have been involved in the medical field for the past 40 years. I am a surgical devices consultant for Novartis Animal Health, where I help educate and train veterinarians, vet students, vet technicians and sales personnel. I earned my MBA from Indiana University.
Q. The variety of suture material sizes is overwhelming. What is the very least a general practitioner should have to perform general surgery?
A. Choice of suture material is almost always based on personal preference and always on good science, as long as basic rules are followed. Most veterinary surgeons will either use only monofilaments or only braided sutures for the vast majority of their surgical procedures.
Monofilaments include Monocryl, PDS, Biosyn, Maxon, nylon, Prolene. Braided sutures consist of Vicryl, Dexon and silk. Some think that chromic catgut is a monofilament, but technically it is classified as a twisted suture, which is closer to a braided product than a monofilament.
Q. Which questions should be asked before reaching for any suture?
A. What tissues layers am I going to close? Can I do this procedure with one strand of suture? Is the needle type adequate to easily penetrate the tissue I am working with? How long do I think it will take for this wound to heal?
What is the weight of this animal? Will my suture hold up with this patient’s post-op activity?
For oral surgery, how long do I need the suture to stay in place and what will be most comfortable to the patient: a monofilament, braided or twisted suture?”
Q. What is the ideal number of knots for various suture types?
A. To some degree, it depends on the manufacturer. All of Ethicon’s sutures are designed to use four square knots. In some cases you could use a surgeon’s knot followed by two square knots.
Q. Is the type of needle really such a big deal?
A. Yes. The type, shape and length of the needle are very important. The type of needle (cutting, reverse cutting or taper) will depend on the tissue you are suturing.
The shape is important because surgeons need to be able to work comfortably and without being encumbered in the area of the body where they are working, for example in a deep body cavity. Also, swaged needles are less traumatic than needles with an eye.
The length of the needle is also important because of the risk of bending and/or breaking the needle. If the surgeon takes too big a bite of tissue, he runs the risk of damaging the needle as well as causing further trauma to the tissue.
Q. Are sutures with antiseptics just a marketing gimmick, or do they have a role in general practice?
A. Antibacterial sutures are important in veterinary surgery because the patient may be, or already has been, exposed to staph A, staph E, MRSA, MRSE, E. coli and Klebsiella pneumonia.
To help reduce the risk of spreading these diseases during the operation, Triclosan has been added to several Ethicon products to prevent bacterial colonization to the suture thread.
Q. What about catgut?
A. Most surgeons have either stopped using or have greatly reduced their use of chromic catgut. The material is reactive and prone to fraying and/or breaking. The absorption profile is unpredictable and the major manufacturers of chromic gut do not even include a tensile strength profile in their package inserts.
Conversely, the synthetic sutures do not have the fraying and breaking issues and the reactive tendency of catgut.
Q. What are your thoughts on using steel sutures in the linea?
A. Most surgeons prefer to use a synthetic, absorbable suture to close the linea because of its ease of use. The concern with using stainless-steel suture is the difficulty they have using this product. If it kinks, they run the risk of the suture breaking when trying to place it in the linea or breaking at some point in the future. Again, most surgeons prefer to use an absorbable rather than a non-absorbable suture to close the linea.
Q. What are your thoughts on suture on spools?
A. It is really not the best medicine! There is a high risk of cross-contamination when using suture cassettes. It is interesting to observe that while these products are used in veterinary medicine, they are not used in human hospitals or surgery centers, at least in the U.S. The primary reason spool sutures are not used in humans is because of the risk of introducing or spreading infection.
Cassette sutures are primarily purchased because people think they are saving money. However, how can we be sure the suture material in the cassette remains sterile from case to case, day to day, month to month, as the product sits on a shelf, collecting dust? Further, to use spooled suture you have to buy needles and possibly sterilize the product. It takes time for the staff to prepare these products for use. The cost efficiency of using cassette sutures is highly questionable.
Q. Why do you think skin sutures are better than skin staples?
A. Surgeons usually experience a more precise closure with needle and thread than they do with a skin stapler. First, they are more experienced with using needle and thread.
Second, many surgeons closing with a stapler tends to rush the skin closure as they are trying to save as much time with this part of the procedure as possible. In fairness, some surgeons do a very nice job closing the skin with a skin stapler, but most of them do a better job with suture material. <HOME>
Dr. Phil Zeltzman is a small-animal board-certified surgeon at Valley Central Veterinary Referral Center in Whitehall, Pa. His website is DrPhilZeltzman.com.
This article first appeared in the October 2009 issue of Veterinary Practice News