ONCOLOGY - Surgery

Question 1

Which factors should you consider before proceeding with oncological surgery?

Answer 1

1. What is the histologic type, grade and stage of neoplasia?
2. What are expected local and systemic effects of this type, grade and stage of neoplasia?
3. Is treatment possible and what are the cosmetic and functional costs?
4. Is oncological surgery indicated at all?
5. What are the alternative or combined treatment options?

Question 2

What are the principles of oncological surgery?

Answer 2

1. Resect the tumour with appropriate margins
2. Plan the biopsy in a way that allows for the biopsy tract to be resected with the tumour
3. Consider all scars from previous surgeries, biopsies and drains and ensure they are resected with the tumour (assume all scar tissue has neoplastic tissue within it and resect with appropriate margins)
4. Ligate the blood supply early to prevent dessication and seeding neoplastic cells
5. Limit contamination of the surgical field
6. Limit the use of drains

Question 3

What are the different biopsy techniques?

Answer 3

Fine needle aspirate (FNA)
Core needle biopsy
Incisional biopsy
Excisional biopsy

Question 4

What information can be obtained from a fine needle aspirate (FNA)?

Answer 4

Cell type present

Question 5

What are the main advantages of a fine needle aspirate (FNA)?

Answer 5

Fine needle aspirates (FNA) are quick, cheap and easy

Question 6

What are the main disadvantages of a fine needle aspirate (FNA)?

Answer 6

A fine needle aspirate (FNA) is does not provide a definitive diagnosis as only the cells can be examined and thus you cannot examine how the tumour is interacting with the surrounding tissues

Question 7

What are the main advantages of a core needle biopsy?

Answer 7

A core needle biopsy preserves tissue architechture and thus can be used for histological diagnosis

Question 8

What are the main disadvantages of a core needle biopsy?

Answer 8

A core needle biospy requires general anaesthetic

Question 9

What are the two types of needle used for a needle core biopsy?

Answer 9

Tru-cut needle
Jamshidi needle

Question 10

When is a tru-cut needle most approproate for a needle core biopsy?

Answer 10

A tru-cut needle is used for a soft tissue biopsy

Question 11

When is a Jamshidi needle most appropriate for a needle core biopsy?

Answer 11

A Jamshidi needle is used for a bone/bone marrow biopsy

Question 12

What is an incisional biopsy?

Answer 12

An incisional biopsy is where a wedge of tissue is excised, ideally with a margin of abnormal and normal tissue, making sure to plan the incision so the biopsy tract can be resected with the mass eventually

Question 13

What is an excisional biopsy?

Answer 13

An excisional biopsy is where the whole mass is resected with an appropriate margin

Question 14

What are the two classifications of margins of excision?

Answer 14

Radial margin
Deep margin

Question 15

What are radial margins of excision?

Answer 15

The radial margins of excision consists of the skin and associated fat excised radial to the mass

Question 16

What are deep margins of excision?

Answer 16

The deep margins of excision refer to the degree of excision in the tissues deep to the mass

Avoid cone shaped resection as you will underestimate your margins

Question 17

What are the different classifications of tumour resection?

Answer 17

Marginal resection
Local resection
Wide local resection
Radical resection

Question 18

What is a marginal resection?

Answer 18

A marginal resection is tumour excision with a 1 - 2mm radial margin

Question 19

Which tumours are marginal resections appropriate for?

Answer 19

Benign, non-invasive tumours such as lipomas

Question 20

What is a local resection?

Answer 20

A local resection is tumour excision with a 1cm radial margin and a deep margin down to the first fasial plane

Question 21

Which tumours are local resections appropriate for?

Answer 21

Benign, non-invasive tumours such as histiocytomas

Question 22

What is a wide local resection?

Answer 22

A wide local resection is tumour excision with a 2 - 3cm radial margin and a deep margin excising the deep fascial plane

May require referral

Question 23

Which tumours are wide local resections appropriate for?

Answer 23

Wide local resections are used for sarcomas and mast cell tumours

Question 24

What is a radical resection?

Answer 24

A radical resection is a tumour excision with a 3 - 5cm radial margin and a deep margin excising 1 to 2 deep fascial planes, or amputation

Generally will require referral

Radical resection of a feline injection site sarcoma

Question 25

Which tumours are radical resections appropriate for?

Answer 25

Very locally aggressive tumours

Question 26

What are the indications for a splenectomy?

Answer 26

Splenic neoplasia Splenic haematoma Splenic rupture

Question 27

What is the most common splenic neoplasm?

Answer 27

Splenic haemangiosarcoma

Question 28

How do you carry out a splenectomy?

Answer 28

1. Ventral laprotomy incision 2. Gently locate and exteriorise the spleen, identifying the hilus 3. Move from the tail to the head of the spleen and double ligate the hilar vessels close to the hilus 4. Cut between the ligatures 5. Flush the abdomen with 100 - 200ml/kg of sterile isotonic saline 6. Routine abdominal closure 7. Send the spleen for histopathology 8. Make sure to biopsy any lesions identified during surgery *(i.e. any liver lesions)*

Question 29

What are Halstead's principles of surgical technique?

Answer 29

Strict adherence to aspectic technique Gentle tissue handling Sharp anatomic dissection of the tissues Miticulous haemostasis Obliteration of dead space Avoidance of tension

Question 30

How do you ensure strict adherence to aseptic technique?

Answer 30

Aseptic patient, surgeon and surgical instrument preparation Appropriate surgical clipping and draping Perioperative antibiotics Cover wounds post-operatively until the patient leaves the practice

Question 31

When are perioperative antibiotics indicated?

Answer 31

Perioperative IV antibiotics are indicated if the surgery exceeds 90 minutes, and should be repeated every 90 minutes

Question 32

Why is gentle tissue handling so important?

Answer 32

Gentle tissue handling is so important as tissue trauma can cause inflammation and increase the risk of infection and wound dehiscence

Question 33

How do you ensure gentle tissue handling?

Answer 33

Use appropriate surgical instruments Keep tissues moist to avoid tissue dessication Use stay sutures to manipulate the skin edges

Question 34

How do you ensure sharp anatomical dissection of the tissues?

Answer 34

Make sure to use a scalpel where possible over blunt dissection. When blunt dissection is required, use metzenbaum scissors as these are much sharper than mayo scissors

Question 35

How do you maintain meticulous homeostasis?

Answer 35

Use haemostats to control bleeding Use diathermy if available Dab tissues with swabs to remove the blood rather than wipe the tissues

Question 36

What is diathermy?

Answer 36

Diathermy is the use of heat from an electrical current to seal off bleeding vessels

Question 37

How can you obliterate dead space?

Answer 37

Careful tissue dissection Use sutures to close the dead space *(i.e. walking sutures)* Surgical drains

Question 38

What are the two forms of surgical drains?

Answer 38

Open passive surgical drains Closed active surgical drains

Question 39

How do open, passive surgical drains work?

Answer 39

Open, passive surgical drains rely on gravity and capillary action to drain fluid from the body

Question 40

Give an example of an open passive surgical drain

Answer 40

Penrose surgical drain

Question 41

How do you place an open, passive surgical drain?

Answer 41

If using a penrose drain, insert the drain into the surgical wound or cavity, making sure the drain is positioned to allow for passive drainage of any fluid that may accumulate - this is typically at a lower point where fluid tends to collect. Anchor the drain internally. The drain should exit the body at a point distant from the surgical site through a stab incision in the skin. Use sutures to secure the drain to the skin near its exit point

Question 42

How do you manage an open passive surgical drain?

Answer 42

1. Cover the drain with a dressing while the patient is in the clinic *(this dressing can usually be removed once the patient goes home)* 2. Make sure to put buster collars on dogs with drains as they will eat the drain 3. Monitor the fluid volume accumulating within the dressing, and when it begins to reduce (usually between 2 to 5 days), the drain can be removed

Question 43

How do closed, active surgical drains work?

Answer 43

Closed, active surgical drains rely on a vacuum to drain fluid from the body

Question 44

Give an example of a closed, active surgical drain

Answer 44

Jackson Pratt surgical drain

Question 45

How do you place a closed, active surgical drain?

Answer 45

If using a Jackson Pratt drain (which consists of a flexible tube connected to a bulb which will create suction), insert the tubing into the surgical wound or cavity. The drain should exit the body at a point distant from the surgical site through a stab incision in the skin. Secure the tube to the skin with a Chinese dinger trap suture near its exit point. Compress the bulb/collection chamber and attach it to the tubing to generate a vacuum

Question 46

How do you manage a closed active surgical drain?

Answer 46

1. Make sure to dress the skin interface 2. Monitor the fluid volume accumulating within the dressing, and when it begins to reduce (usually between 2 to 5 days), the drain can be removed

Question 47

What is the main benefit of a closed active drain over an open passive drain?

Answer 47

A closed active surgical drain is a closed system so there is a reduced risk of infection compared to an open, passive surgical drain

Question 48

Why is it so important to avoid tension when closing wounds?

Answer 48

If the wound it under tension, this increases the risk of wound dehiscence and the wound will be more uncomfortable for the animal

Question 49

How can you avoid wound tension?

Answer 49

Incise parallel to tension lines Close the wound in layers Undermining Use tension distributing sutures Skin flaps and grafts

Question 50

What are tension lines?

Answer 50

Tension lines are lines of tension created by the linear arrangements of fibrous tissue in the dermis

Question 51

What are the benefits of closing incisions in layers?

Answer 51

Closing incisions in layers distributes the tension as well as reduces dead space

Question 52

What is undermining?

Answer 52

Undermining is the careful seperation of the skin from the underlying layers to create more mobility and reduce tension. It is important to undermine below the cutaneous trunci muscle or the subcutaneous fat to preserve the blood supply

Question 53

Which suturing techniques can be used to relieve tension on wounds?

Answer 53

Walking sutures (very painful) Cruciate Horizontal mattress Vertical mattress Far-near-near-far Far-far-near-near

Question 54

What are 'dog ears'?

Answer 54

'Dog ears' are puckered areas of skin which can form where two skin edges meet during wound closure. This is a cosmetic issue which will flatten with time

Question 55

What can be done to prevent 'dog ears'?

Answer 55

Make elliptical incisons Incise parallel to the tension lines

Question 56

What are advancement skin flaps?

Answer 56

Advancement skin flaps are a technique used to close wounds by advancing adjacent skin over the wound

Question 57

How big can you make advancement skin flaps?

Answer 57

You can only make advancement skin flaps two times as long as the width of the base or the skin will become necrotic at the tips due to a lack of vascular supply

Question 58

How do you carry out an advancement skin flap?

Answer 58

Ensure there is enough skin adjacent to the wound. Incise appropriately and undermine the skin. Advance the skin flap over the deficit and suture it in place

Question 59

What is an H-plasty?

Answer 59

An H-plasty is an advancement skin flap using two smaller flaps adjacent to the deficit

Question 60

What are axial pattern flaps? | This is referral surgery

Answer 60

Axial pattern flaps are large, very robust skin flaps which have their own direct cutaneous artery and vein at their base, and can be maneuvered large distances

Question 61

What are skin grafts?

Answer 61

Skin grafts are where a piece of skin is removed and attached to a completely different area of the body, and develps a blood supply from a healthy bed of granulation tissue

Question 62

Where is a skin graft usually taken from?

Answer 62

Thoracic wall

Question 63

How do you manage a skin graft?

Answer 63

A skin graft must be completely immobile to revascularise. Bandages and external skeleton fixators can be used to achieve this

Question 64

What should you do if you are unable to close a wound?

Answer 64

If you are unable to close a wound, dress the wound and seek help. DO NOT attempt to close a wound under too much tension as these wounds will be very painful, fail and if on limbs can cause a tourniquet and limb loss