General cutaneous surgery

Question 1

Define an abscess

Answer 1

a localised collection of pus

Question 2

Abscesses are nearly always…

Answer 2

secondary to a bacterial infection, pus is full of bacteria and dead bacteria within white blood cells

Question 3

What are sterile abscesses?

Answer 3

No bacteria are involved but an accumulation of dead and dying cells and tissues with a fibrous capsule

Question 4

Describe a malar abscess

Answer 4

Associated with dental disease. Extraction of the offending tooth is required, usually the carnassial tooth.

Question 5

Describe an anal sac abscess

Answer 5

Impactions of anal gland secretions can lead to abscess formation.

The abscess normally ruptures out of the skin around the anus.

Question 6

Describe a cat bite abscess (CBA)

Answer 6

Canine teeth penetrate deep into the skin leaving only a small entry wound. The wounds quickly heals over sealing bacteria beneath the skin

Question 7

Describe penetrating wounds

Answer 7

• as with CBA, the skin is penetrated and heals over quickly leaving bacteria to multiply beneath the skin e.g. thorn, nail etc

Question 8

Describe foreign bodies

Answer 8

an object e.g. grass seed, wood splinter penetrates the skin; the entry hole quickly heals over sealing the foreign body within the tissues

Question 9

Describe a rabbit abcess

Answer 9

rabbits get recurrent abscesses in the submandibular and cheek area

the pus within is much thicker and is difficult to drain and remove

commonly related to tooth root problems and/or nasolacrimal disease

Question 10

What are the clinical signs of an abscess?

Answer 10

Local swelling

Local pain

Warmth and erythema of the overlying skin

Systemic signs – pyrexia, depression, anorexia, tachycardia

discharge

Question 11

Describe treatment of abscesses

Answer 11

Cold (sterile) abscesses can form if antibiotics are given without lancing and releasing the encapsulated pus

Lance an abscess where it begins to ‘point’ (soft spot)

Warm compresses can encourage an abscess to point and even rupture

GA or sedation is normally needed to lance an abscess

Prepare the site surgically and lance with a scalpel blade (FNA first to confirm)

Express pus and flush cavity out well

Daily flushing and cleaning of the site, prevent a scab from forming

Abscesses need to heal from the inside out

Surgical resection of some abscesses. Rabbit abscesses best treated this way.

Question 12

Describe problems that tumours can cause

Answer 12

The physical mass of the tumour can press on other structures in the body and cause pain or loss of function

Rapidly growing tumours can use up energy resources and cause the animal to feel unwell and depressed

Cytokines released by a tumour can cause distant physiological effects. E.g. anal adenocarcinoma and lymphosarcoma can cause hypercalcaemia, which can cause polydipsia, polyuria and renal failure.

The tumour may spread to vital organs e.g. the heart, kidneys, lung, liver resulting in loss of function and clinical signs.

Question 13

Describe a benign tumour

Answer 13

Usually have a well developed capsule and remain in one site

Question 14

Describe a lipoma

Answer 14

Adipose (fatty) tissue tumour

Question 15

Describe a histiocytoma

Answer 15

Commonly seen in dogs under the age of three years, occasionally in older animals

Commonly spontaneously regress without treatment

Question 16

Describe an adenoma

Answer 16

Benign tumour of the glandular tissue e.g. anal adenoma, adenoma of the thyroid gland

Question 17

Describe a papilloma

Answer 17

‘Warty’ growths found on the skin, occasionally the bladder, arising from the epithelial tissue

Question 18

Describe a malignant tumour

Answer 18

Often show ulceration, local infiltration and metastasis

Question 19

Describe a carcinoma

Answer 19

Produced from the epithelium e.g. squamous cell carcinoma, mammary tumours (adenocarcinomas)

Question 20

Describe a malignant melanoma

Answer 20

Strictly should be called a melanocarcinoma

Question 21

Ideally, before removal, any tumour…

Answer 21

should be FNAed to give an indication of the type of tumour before removal so the surgical margin adjusted as needed. Skin grafts may be required
to close the deficit

Question 22

Describe a pedicle graft

Answer 22

A pedicle graft or skin flap is a partially detached segment of skin and subcutaneous tissue

The base or pedicle of the flap maintains circulation to the skin during transfer to a recipient location

This location can be local or distant, advanced or rotated

Question 23

Describe a Single Pedicle Advancement flap

Answer 23

A flap is undermined to the side of the defect and advanced over the wound

The defect and the sides of the flap are then sutured

Question 24

Describe a Bipedicle Advancement Flap

H-plasty

Answer 24

As a single pedicle advancement but skin is undermined from both sides of the wound

The skin is then advanced on both sides to meet in the centre and cover the defect

Question 25

Describe a rotational flap

Answer 25

A curved lesion is made adjacent to the wound

The length of the incision usually needs to be about four times the width of the wound

Used where the skin can only be mobilised from one side of the wound e.g. around the anus

Question 26

Describe a Transposition Flap (90˚)

Answer 26

Transposition flaps are developed at angles of up to 90˚

They tend to be moved from the thoracic or abdominal skin to cover wounds affecting proximal limbs

Question 27

Describe skin free grafts

Answer 27

Segments of skin are completely detached from one area of the body to ‘resurface’ another area lacking epithelial surface

No vessel attachment at all

Question 28

Describe the survival of free skin grafts

Answer 28

Survival of the graft in the first 48 hours is by absorbing tissue fluid from the recipient bed

Later on new blood vessels grow into the graft

Post operative care is therefore vital to graft survival

Accumulation of material (blood, pus) under the graft or movement delays or prevents revascularization and often leads to non-adherence and graft necrosis

Question 29

Describe a punch graft

Answer 29

Grafts usually taken with a punch biopsy and pushed into ‘holes’ in the granulation tissue

Question 30

Describe a stamp/strip graft

Answer 30

Small squares or strips of skin laid onto granulation tissue with gaps between the grafts

Question 31

Describe Post Operative Care of Free Skin Grafts

Answer 31

Analgesia must be provided

Survival of the graft depends on optimising the conditions that promote adherence and nutrition

Bandaging –

Promotes good contact between the graft and base

Minimises movement

Removes exudates with correct dressing use

Prevents soiling and bacterial contamination

Correct bandaging is very important. Too tight and blood flow is reduced, too loose and contact is not maintained between the graft and base

Complete rest (cage rest) is essential for the initial five days post surgery. Exercise must be restricted for 10-14 days