Knot Tying Principles
Avoid extra throws
- adds unnecessary bulk - esp. near the skin
When trying to bury a knot for intradermal closure, which surgical knot tying principle is most important to keep in mind?
- avoid large suture - avoid extra throws
Tie flat, secure square knots
- avoid vertical tension - "set" the knot on final throw - size of loop determined by first 2 throws you make -- loosest loop for skin, super tight for ligation - throws 3, 4, 5 are mechanical process -- how tight these are made has NO impact on the loop, but impacts knot security
Square knot tying techniques
- direction of wrapping around needle holder is always TOWARD short strand - pull in opposite direction -- strands should become 180 degrees from their original position
Horizontal tension
- equal and opposite - uniform rate and tension
Avoid excessively large suture
- esp. near skin surface - if increase suture size by 2 sizes = 4-6 fold increase in knot volume = 2 fold increase in reactivity - bigger is NOT better - want larger suture for ligation because don't want to accidentally cut through
Use simplest, secure knot
- interrupted pattern = use 5 throws - continuous pattern (end knot) = use 1-2 additional throws -- exception is intradermal closure
Avoid friction between strands
- may weaken suture - accentuated by vertical tension - do not grab suture material with needle holders unless throwing excess away --> weakens suture and can cause failed knots - *suture chatter* = can hear pulling on strands before loop is actually together
Cut knot ends short
- synthetic materials = 3 mm - surgical gut = 6 mm
Use appropriate tension
- tissue approximation = not too snug because can cause swelling - ligation (strangulation) = tightest
Principles of Knot tying
1. use the simplest, secure knot 2. cut knot ends short (3mm or 6mm) 3. avoid friction between strands 4. use appropriate tension when tying -- tissue approximation, ligation (strangulation) 5. tie flat secure knots 6. equal, opposite horizontal tension 7. avoid extra throws 8. avoid excessively large suture (esp. near skin surface)
