Product Manual

a reliable means of maintaining wound apposition because any tension applied to the

“ears” from the patient’s side of the knot will unlock the knot. The addition of the

second throw to the surgeon’s knot square (2=1) will provide additional resistance to

wound disruption, but this knot will not advance by slippage, limiting the surgeon’s

ability to secure meticulous coaptation of the wound edges.

In contrast, two-throw square (1=1) or granny (1x1) knots can be advanced to the

wound surface to secure precise wound edge apposition. These two-throw square

(1=1) or granny (1x1) knots can be easily converted into their respective slip knots by

applying tension to only one “ear” in a direction that is perpendicular to that of the

tissue surface. Square (S=S) or granny (SxS) slip knots require lower knot rundown

force for knot advancement than either the square (1=1) or granny (1x1) knots, but

will never reach knot security even with 5 throws. 9 The risk of tying slip knots can

be obviated by applying tensions to both “ears” in horizontal planes parallel to the

tissue surface. The second step in knot construction is the addition of a sufficient

number of throws to the knot so that it does not fail by slippage. The magnitude of

knot breakage force is always greater than that for knot slippage force of a comparable

suture, ensuring optimal protection against wound dehiscence. The magnitude of knot

breakage force is significantly influenced by the rate of application of forces to the

knot. When constant force is applied slowly to the knot “ears,” the knot breakage force

is significantly greater than that for knots in which the same constant force is applied

rapidly to the “ears.”

VI. tying techniques (cont’d)