Clinical Studies

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Reasons for surgery

1. Therapeutic Reasons (treatment)
2. Diagnostic(exlap or biopsy)
3. Increased suitability for particular use (castration or dehorning)
4. Biomedical Research
5. Cosmetic reasons

\-Ectomy

surgical removal of…

\-Otomy

incision into or opening

\-Ostomy

Creation of (semi)permanent opening or stoma

\-Pexy

Fixation

\-Centesis

Perforate or tap

\-Oscopy

Use of fiberoptic instruments for diagnosis and surgery

When are scalpels used

Dense tissue e.g skin

minimise collateral damage and crushing

When are scissors used

Loose tissue e.g adventitia and fat

cause crushing and bruising

Cautery

direct application of heat

Uses: disbudding

Electrosurgery

generation of a electrical waveforms that cause coagulation and tissue cutting

Monopolar Electrosurgery

Uses an electrode under patient (dispersal pad). current travels from active electrode through patient.

Dipolar Electrosurgery

active and return electrodes are at the tips of forceps. only tissue grasped is part of circuit.

Laser surgery

Light amplification by stimulated emission of radiation. forms cutting tool used to ablate/vapourise/weld tissue

Endoscopic / telescopic equipment

used for minimally invasive surgery

Arthroscope

lensed eyepiece with camera and light source that provides a scope in joints or tendon sheaths

Advantages of arthroscopy

1. Minimally invasive
2. Decreased Hospital stay
3. Better Field of view: magnification and lighting

Most common life-threatening surgery complications

infection and haemorrhage

Aspects that improve surgery sucess

1. Reduced tissue trauma
2. Aseptic techniques

Halsted’s Principles

1. Gentle tissue handling
2. Meticulous haemostasis
3. Preserve blood supply
4. Strict aseptic techniques
5. Minimise tension on tissues
6. Eliminate dead space
7. Meticulous approximation of wound layers
8. Minimise foreign material in wound (Extra principle)

Rough handling during surgery causes:

1. Post-operative infection
2. Delayed healing
3. Increased surgical shock
4. Increased pain and dysfunction

Results of affective haemostasis

1. Better surgical conditions
2. Lessens chance of haemorrhagic shock
3. Lessens chance of post-op infection

Aseptic technique reduces

Risk of post-op infection

Why is surgery performed within a theatre environment

Protect patient from contact and airborne bacteria

Why prepare patient’s skin

protect them from their own flora

Why minimise tension on wound edges

Tight sutures can tear tissue and reduce wound strength.

Strangulation and tissue death can cause infection and delay healing

Dead space

Accumulation of blood and fluid in tissue space.

Delays healing and increases risk of infection

Results of meticulous approximation of wound layers

1. Promotes rapid healing
2. Increased wound strength
3. Lessens chance of infection

What needs to be noted in History taking

1. Overall health
2. Intercurrent diseases
3. Owners expectations
4. Are the owners able to cope with the aftercare

Pre-operative information required

1. Time available
2. Signalment of patient
3. Financial capacity of owner

What is a wound

Injury to the body tissue resulting in disruption to normal cellular and anatomical continuity

4 Phases of Wound Healing

1. Inflammatory
2. Debridement
3. Proliferative (repair)
4. Remodelling (Maturation)

Features of the inflammatory phase

Features of the inflammatory phase

1. 6 hrs after injury
2. neutrophils accumulate and phagocytose debris

Features of the debridement phase

1. Within the first 12 hrs after wounding
2. epithelialisation
3. migration of fibroblasts→ collagen formation
4. Granulation formation
5. Wound contraction

Features of Proliferative phase

1. Resistant to local infection
2. Barrier to systemic infection
3. Blood supply
4. Supports fibroblasts

Features of Granulation tissue

1. 3 weeks after injury
2. collagen undergoes functional orientation
3. increase in tensile wound strength
4. scar formation (15% weaker)

Features of Remodelling phase

1. Reduced movement over joints
2. Stenosis of a body opening
3. Thin epithelium

Disadvantages of wound contraction

1. Clean
2. Clean-contaminated
3. Contaminated
4. Dirty

4 Wound Classifications

* Surgically created under ideal operative conditions
* No entry into GI, Genital-urinary or respiratory tracts

Characteristics of a Clean wound

* Minimally contaminated/ contaminants easily removed
* Operations into GI, GU or R tracts
* Minor breaks in aseptic technique

Characteristics of a Clean-contaminated wound

* Fresh or operative wounds with minor breaks in aseptic technique
* spillage of GI or GU tract contents

Characteristics of Contaminated wound

* Old traumatic wounds
* Clinical infection
* abscess or perforated viscera

Characteristics of a Dirty wound

Restoration of tissue continuity occurs directly, without granulation

Primary Closure

Wound repair accomplished with granulation tissue

Healing by Secondary intention

Wound closure 3-5 days after time of infection, Before granulation tissue is formed.

When contamination cannot be removed or definitive debridement cannot be formed

Delayed Primary tissue healing

closure in the presence of granulation tissue

5-10 days post injury

Secondary Closure

1. Expense
2. prolonged healing
3. May not completely heal
4. large defects
5. impairment of function

Disadvantages of Secondary healing

removal of all debris, necrotic tissue or obviously devitalised tissue

Surgical debridement

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1. prevent further contamination
2. lavage -flushing
3. debridement
4. drainage
5. closure
6. bandaging

Steps of contaminated wound management

material applied directly to the wound

primary layer

Dressing

1. Contact (primary)
2. Intermediate (secondary)
3. Outer (tertiary)

### 3 layers of a bandage

Holds primary dressing in place, eliminates dead space, absorb exudate

Function of intermediate bandage

Protect underlying layers, establish pressure and stops fluid leaking

Function of tertiary bandage layer

dressings that don’t serve any additions function

Passive dressing

Dressings that contain factors that speed up healing

Active dressings

indicated for wounds that have necrotic tissue, foreign matter or viscous exudates on their surface

Wet-to-dry dressings

only if wound exudes copious quantities of low-viscosity fluid that does not tend to aggrogate

Dry-to-dry dressings

1. Sufficient moisture
2. Complete contact
3. Correct temperature
4. Correct contact time

4 Conditions of Steam Sterilisation

1. Steam readily available
2. Cheap
3. Rapid
4. Reliable
5. Sterilizes most articles
6. Can be stored

1. Steam readily available
2. Cheap
3. Rapid
4. Reliable
5. Sterilizes most articles
6. Can be stored

Disadvantages of autoclaves

1. Requires special equipment
2. Requires careful monitoring
3. Cannot sterilize sharp or delicate instruments, oils and powders

Advantages of Dry heat sterilization

Kills organisms by oxidative denaturation of proteins


1. Simple
2. Cheap
3. Sterilizes oils and powders
4. doesnt dull sharp instruments
5. No moisture, non-corrosive

Disadvantages of dry heat

1. long exposure times
2. poor penetration
3. careful load technique
4. required careful monitoring
5. unsuitable for heat sensitive material

conditions for chemical sterilisation

must be non-corrosive and is used for delicate items e.g lensed arthroscopes

Gamma Raditaion

disrupts normal cellular metabolism at atomic levels

Sterility indicators

1. Indicator strips
2. Browne tubes
3. Biological indicators

How strong should a suture be

at least as strong as the tissue, depends on collagen

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fascia/skin > viscera > muscle/fat

Disadvantages of using excessively strong sutures

Tend to be thicker or braided which increase risk of infection

What do natural fibre sutures induce

Inflammation and immune response

Absorption occurs via phagocytosis

What do synthetic fibres induce

designed to be minimally inflammatory and absorption occurs mainly via hydrolysis

Features of monofilaments

pros- tend to be more bactericidal, less tissue drag

cons- weaken when crushed, coatings reduce knot security

common antibacterial coating

1. Monocryl Plus
2. Coated Vicryl Plus
3. PDS II Plus

\
all coated with Triclosan

Multifilament sutures

Pros- easier to handle, better knot security

Cons- Capillarity

9 Characteristics of sutures

1. Maintain adequate tensile strength
2. Stimulate minimal inflammation
3. Discourage bacterial growth
4. Non-capillary
5. Non-Allergenic
6. Non-Electrolytic
7. Non-Carcinogenic
8. Good handling properties
9. Good knot security

Improper sutures alter biological healing by causing

1. Tissue reaction
2. Potentiation of infection
3. Sinus infection
4. Potentiation of calculi, thrombi and ulcers

Why do we use the smallest suture size possible

1. Less tissue trauma
2. Less suture material volume
3. Smaller knots
4. Greater knot security
5. Encourages gentle handling

Closed eye needles

for use with suture material on reels

Advantages of swaged needles

1. Available for immediate use
2. Unlikely to detach suture material
3. Guaranteed sterile
4. Less tissue trauma
5. Less handling of suture material

Disadvantages of eyed needles

suture may fall out of eye→ contamination of surgical field

Haemostasis

bleeding is halted by vasoconstriction and coagulation by surgical means

Primary haemorrhage

Haemorrhage that occurs immediately after vessel is opened

Delayed Haemorrhage

1. Intermediate

Methods to achieve preventative haemostasis

1. Careful planning
2. Ligation/ coagulation of vessels
3. Gentle and accurate dissection

Advantages of Meticulous Haemostasis

1. Reduced blood loss
2. Promotes tidy surgery
3. Maintains tissue health
4. Maintains tissue perfusion
5. Good visualisation of tissue

Methods of stopping Haemorrhage

1. Pressure
2. Artery forceps
3. Suture ligation
4. Metal clips cautery
5. Tourniquets
6. Haemostatic agents

signs of fractures

1. pain
2. dysfunction
3. blood loss
4. nerve injury
5. perforated organs

Bone blood supply

1. periosteal artery (most important in repair)
2. principle artery
3. metaphyseal artery
4. nutrient artery (2/3 cortical supply)
5. epiphyseal artery

Secondary bone healing

* callus stabilises fracture
* laminar growth fills gap

Incomplete fracture

greenstick or fissure fractures. Only 1 cortices cracked

Simple Complete fracture configurations

* transverse
* short oblique
* long oblique
* spiral

Comminuted complete fractures

* butterfly
* comminuted
* segmented

Treatment of open fractures

1. Prevent further contamination
2. Aseptic debridement
3. Preserve blood supply and nerves
4. Stable fixation - ideally ESF
5. Early limb mobilisation

Grade I open fracture

* bone retracts
* small wound
* good prognosis and splint within 6 hrs

Grade II open fracture

* wound > 1 cm
* no excessive soft tissue damage
* some foreign material

Grade III open fracture

* excessive skin damage
* muscle and neuro-vascular damage
* extensive treatment

Articular fractures

1. Extra-
2. Partial
3. Complete
4. Physeal

Extra- articular fracture

* separate from diaphysis
* metaphyl- adults
* Physeal- young

Partial Articular fracture

* section of articular surface e.g unicondylar

Complete articular fracture

* joint surface fractured
* separate from diaphysis
* e.g bicondylar

Salter-Harris classifications