Principles of surgery

Question 1

What are Halsted’s principles and what are their purpose?

Answer 1

Lay out guidelines to optimise the outcomes of surgery.
1) handle tissues gently
2) be meticulous in controlling haemorrhage
3) Preserve blood supply to tissues
4) Observe strict aseptic technique
5) Ensure tissues are accurately apposed
6) Obliterate dead space

Question 2

What is dead space?

Answer 2

Space remaining in tissues as a result of failure of proper closure of surgical or other wounds, permitting accumulation of blood or serum.

Question 3

What are heavy + blunt ended scissors, fine vascular scissors, serrated dissecting forceps, and toothed dissecting forceps used for?

Answer 3

blunt - for blunt dissection and cutting sutures
fine vascular - for dissection of fine/delicate tissue, serrated and toothed are for grasping tissue

Question 4

What are haemostats and retractors?

Answer 4

Haemostats - clamp blood vessels to stop bleeding
Retractors - retract tissues and allow the surgeon to visualise structures

Question 5

What are some methods to ensure aseptic technique?

Answer 5

wear appropriate scrubs, clip the fur of the animal and disinfect with appropriate antiseptic, clean instruments and suture materials, autoclave swabs and drapes, have a room solely for procedures

Question 6

How long should you wash your hands for when preparing for surgery

Answer 6

At least 5 minutes

Question 7

What size innoculum is enough for infection to be established?

Answer 7

105/g

Question 8

How to decrease risks of post-operative infection

Answer 8

Use animals that are young/healthy
Create small surgical incisions.
Short duration of surgery

Question 9

What is the “no touch” technique?

Answer 9

The instrument tips come into contact with the animal, and the tips are re-sterilised between each animal to avoid breaks in aseptic technique

Question 10

What technique may be used to sterilise instruments during batch surgery?

Answer 10

Hot bead steriliser

Question 11

Can you re-sterilise scalpel blades?

Answer 11

No, as this will result in the blade becoming more blunt

Question 12

When may it be appropriate to undertake surgery in a general-purpose lab?

Answer 12

If the procedure is non-recovery

Question 13

What are the components for aseptic surgery?

Answer 13

Areas for surgical support
Animal preparation
Preparation of the surgical team
Operating
Post-operative recovery

Question 14

What components of a surgery ROOM for aseptic surgery should be present?

Answer 14

Positive pressure (effective ventilation), surgical lighting (cold light source), adjustable height surgical table, patient warming, preparation area, post-op recovery area

Question 15

What are the main ways of physical (thermal) sterilisation?

Answer 15

Thermal energy:
Wet heat: boiling water is considered disinfection rather than sterilisation, and this is not suitable for rubber.
Steam sterilisation: autoclave
Dry heat: hot air ovens sterilise things that cannot be exposed to moisture. Hot bead steriliser is useful for batch surgery involving rodents - tips of instruments are placed in a heated beaker of plastic beads at 250C for 10-15 seconds.

Question 16

What is cold chemical sterilisation and what solution is usually used for chemical sterilisation?

Answer 16

Ethylene oxide
Involves soaking instruments in disinfectant solutions over a long period of time (doesn’t kill spores and viruses)

Question 17

Why is haemorrhage a problem during surgery?

Answer 17

It obscures the surgical field
May cause shock/death
Provides a medium for bacterial growth
Forms haematomas in dead space, inhibiting proper healing and further increasing risk of infection

Question 18

How can bleeding be controlled during surgery (3)?

Answer 18

Pressure - through a moistened gauze swab for at least 2 mins, a clot should seal the hole.
Electrocautery - uses electrical current to seal the vessel
Ligatures - metal clips can be used for clamping blood vessels, or absorbable sutures can be used

Question 19

What are the definitions of clean wound, clean contaminated, contaminated, and dirty?

Answer 19

clean - no infection
clean contaminated - a minor break in aseptic technique or a minor hollow organ is opened
contaminated - extremely rarely, where gross spillage from a hollow organ or a major break in aseptic technique has occurred
dirty - should not be encountered

Question 20

What are the different types of wound closure?

Answer 20

Primary closure - closing the wound with a minimum of granulation tissue
delayed primary closure - closed several days after the wound occurs because it is too contaminated to close at first
Secondary closure: leaving the wound open for several days until a granulation bed is established

Question 21

What are round-bodied needles used for?

Answer 21

To separate tissue fibres rather than cut them, and are either used for soft tissue (fat) or muscle

Question 22

What are characteristics of suture materials?

Answer 22

Easy to handle
Promotes rapid healing
Holds the wound together and has high tensile strength
Non-irritant

Question 23

Describe how to place a suture

Answer 23

Use needle holders to position needle perpendicular to the long axis of the holders, in the middle third of the needle, nearer the eye than the tip
Use forceps to stabilise the tissue
Drive needle through in a single rotating motion
Pull the suture through the wound and tie the knot

Question 24

What is the theory of knot tying (principles) and what are the main suture patterns?

Answer 24

Use the simplest knot to provide the security required
Do not over-tighten knots
Do not use any crushing instruments (haemostats)
Keep the ends of the suture as short as possible

Interrupted stitch (horizontal mattress)
Continuous stitch (subcuticular pattern

Question 25

Which stitch should be used on the muscle layer?

Answer 25

Interrupted suture pattern

Question 26

How far apart should clips be placed, and what is a disadvantage of them?

Answer 26

8-10 mm, should be removed 8-days after

Potential for over-tightening