Ligation

Question 1

What is a ligature?

Answer 1

Piece of suture tied around a blood vessel/hollow structure to shut it off - haemostats

Question 2

When ligating blood vessels, what knots are preferable and why?

Answer 2

Square knot

When 2nd throw is tightened, tightens the 1st throw too

Question 3

When may surgeon’s knots be used to ligate a vessel?

Answer 3

If the tissue is under tension

ensure don’t loosen 1st double throw as place 2nd

Question 4

Why can’t a square knot be used in tissue under tension?

Answer 4

1st throw would loosen before being able to apply the 2nd throw

Question 5

Which type of ligature is more secure - circumferential or transfixion? Why?

Answer 5

Transfixion

Cannot slip off the end of the vessel

Question 6

What is required to be able to do a transfixion ligature?

Answer 6

Suitably secure, adjacent tissue to blood vessel

Question 7

With what suture material can Halstead and modified transfixion ligatures be used?

Answer 7

Halstead - fine suture material only

Modified - can be used with thicker

Question 8

How many circumferential ligatures can be placed around a vessel?

Answer 8

Usually one or two (some people do 2 to be sure)

Question 9

What is required to be able to do a circumferential ligature?

Answer 9

Sufficient pedicle

Question 10

In a cat spay, what ligatures are used on the ovarian and uterine vessels and why?

Answer 10

Ovarian - circumferential due to lack of adjacent tissue

Uterine - transfixion due to uterine body tissue

Question 11

What technique can be used to make a circumferential ligature more secure? What is this technique?

Answer 11

3 clamp technique - ligate the groove created by the bottom haemostat - cut between top 2 forceps

Question 12

Using the 3 clamp technique, should curved clamps be placed towards or away from the animal? If using straight and curved forceps, which should be closest to the body?

Answer 12

Away

Straight

Question 13

When using the 3 clamp technique, the clamps should be placed in what order?

Answer 13

Starting from closest to body wall

Working upwards

Question 14

How many throws should be placed on top of a transfixion ligature?

Answer 14

Minimum 4

Question 15

When using a modified transfixion ligature, how many throws should be placed onto of the vessel? What are the exceptions to this?

Answer 15

Single
Double if tissue is under tension
Single knot instead of single throw if in deep awkward location (e.g. abdomen) - prevents first throw loosening

Question 16

When doing a transfixion ligature, where should the suture material placed?

Answer 16

Through the adjacent tissue - not the vessel itself