Surgical Principles

Question 1

State the advantages and disadvantages or polyglactin 910 and polydioxanone

Answer 1

Polyglactin 910: - Advantages: - Good size to strength ration - Greater initial breaking strength and stiffness than polyioxanone - Minimal tissue reaction - Excellent handing - Disadvantages: - May cut through friable tissue (esp. if not coated) Polydioxanone: - Advantages: - Maintains tensile strength over prolonger period - (Less memory than polyglyconate) - Disadvantages: - Moderate knot security - Moderate handling

Question 2

What are the disadvantages of an LDS

Answer 2

If double ligation needed, ligature or single vascular clip placed prior to LDS Maximum size: Tissue that can be compress to 0.75mm Mean arterial bursting pressure lower with LDS than for LigaSure or 2-0 PDS so less reliable. Suture ligation also recommended

Question 3

What is the formula for relative knot security

Answer 3

RKS = (KHC/TS) x 100%

Question 4

What are the resorption times for polyglactin 910, polydioxanone, and polyglycolic acid

Answer 4

Polyglactin 910: 56-70 d Polydioxanone: 180 d Polyglyconate acid: 180 d

Question 5

What are the methods of suture degradation?

Answer 5

Hydrolysis

Enzymatic digestion

Phyagocytosis

Question 6

Which 2 factors influence the flexibility of a suture material

Answer 6

Torsional stiffness

Diameter

Question 7

Define loop security

Answer 7

Capability to maintain tight suture loop as a knot is tied

If low, loss of apposition of tissue during knot tying

Question 8

What are the advantages and disadvantages of a double loop suture?

Answer 8

Advantages

Reduces knots

Double strand provides large surface area

Disadvantages

Increased total suture quantity

Bulky knot at the end

Question 9

Which 2 suture materials are best for tying a 4S-modified Roeder knot

Answer 9

Polydioxanone and polyglyconate