Suturing – skin closure

Suture selection

Cosmesis is often important in skin closure. A good subcutaneous closure or subcuticular closure can aid in making the incision heal well. Optimal healing comes with appositional patterns as the cells are already lined up and ready to join.

Large animal species are less likely to chew out their sutures than small animal patients so it is common to use a subcutaneous closure (if needed) + skin closure. Skin closure can be with either an interrupted pattern or a continuous pattern. Cruciates are a more efficient closure pattern than simple interrupteds. Both are more efficient than a subcuticular pattern.  For skin closure, it is very hard to make a simple continuous pattern look pretty; it is much easier to make a Ford-interlocking pattern look pretty.

Subcutaneous tissue is similar across species and most can be closed with 3-0 suture material; however, the needle on 3-0 suture can be very tiny. 2-0 suture with a larger needle may be more appropriate in some situations. Subcutaneous layers are closed with a taper needle. Subcuticular patterns are typically performed with 3-0 suture on a cutting needle.

Cows have very thick skin (think leather) while other LA species have skin similar in thickness to a dog or cat. Cutting needles are required for skin closure in all species. Cow skin is often closed with size 1 to size 3 suture while the skin of horses, pigs, and SRC can be closed with 2-0 to 3-0 suture depending on the location. Ford-interlocking is the most common pattern chosen. Cruciates may be used for non-linear wounds or for a “drainage suture”.* Skin staples can also be used in non-bovine patients but do “pinch” on removal so should only be used in emergencies or where removal won’t result in injury to the person removing them.

Ideally, tension is minimized before skin closure.  If tension is present, tension relieving patterns using larger suture may be needed.  A near-far-far-near (NFFN) type pattern is cosmetic as well as tension relieving. As it is an appositional pattern and will stay in until the tissue is healed, it should not be bigger than 2-0 or 0 in nonbovine patients. If  tension is greater than can be managed with a NFFN suture, vertical and horizontal mattress sutures may be placed temporarily to relieve tension. These patterns will evert the skin edges. The skin can then be closed with an appositional pattern. After 3-4 days, the mattress sutures can be removed, leaving just the appositional pattern. Larger suture (1-2) can be used for the mattress sutures. Stents (tubing or pads) are often used to prevent the larger suture from cutting through the skin.

*suture placed at the ventral aspect if infection is suspected. This suture can be removed to allow drainage without disturbing the continuous pattern.

Note: most ruminants heal quickly and it is often more efficient to leave the wound open rather than to try and close a wound under tension in a cow, sheep or goat.

Simple continuous suture pattern – youtube video

How to use your thumb forceps to stabilize the skin