SA Soft Tissue Surgery: General Surgical Principles and Basic Wound Management Flashcards
Name Halsteads 7 principles of Surgery
Gentle tissue handling- reduced trauma
Meticulous haemostasis- haemorrhage can obscure
Preservation of blood supply- dissect as little as possible
Strict asepsis- prevents surgical wound infections
Minimal tension- wounds under tension will heal more slowly or not at all
Accurate tissue apposition- suture tissues planes back together in same position
Obliteration of dead space
What is the least traumatic cutting instrument?
Scalpel
What are the different grips of holding a scalpel?
Pencil Grip
Fingertip Grip
Palm Grip
What is the purpose of the pencil scalpel grip?
Used for cutting short and precicse incisions due to the small contact area of the scalpel from the anlge
What is this grip and when it it used?
Fingertip grip
Blade to tissue contact is maximised making this a versatile grip used for most scalpel incisions over 3cm
When is the palm scalpel grip used?
Rarely used- allows substantial force but is imprecise
What is press cutting?
Using the pencul grip, apply a gradual increase in pressure in the direct motion of the blade- eg linea alba
What is side cutting?
Using any grip apply pressure at 90 degrees to the direction of the motion of the blade, while other hand tenses the tissue laterally to seperate wound edges incresing cutting efficiency. Only do a single pass, to prevent jagged edges.
What kind of scissors should be used for fine dissection and what for dissecting connective tissue and fascia?
Metzenbaum (top) for fine dissection
Mayo (bottom) for connective tissue and fascia
What kind of dissection are curved scissors better for?
Curved scissors are better for fine dissection.
How should you hold scissors to cut towards your dominant hand?
Backhand thumb-third finger tip is better
When would this technique be used?
To cut across the table towards your body
use the back thumb-index finger grip
Where along the sharp edge of scissors should you cut?
Use the scissor tip rather then near hinge- cutting forces highest at tip
What are the three techniques of cutting with scissors?
Scissor cutting- normal- avoid complete closure of jaws
Push cutting- wrapping paper- useful for cutting sheets of tissue
Blunt dissection- insert closed blades of scissors anf then open them
How do electrosugical instruments work?
Use a radiofrequency electrical current to heat tissues and destroy cells/coagulate protein
What is the difference between monopolar electrocuautery and bipolar?
Monopolar electrocautery has an electrode in a hand peice and a ground plate and can both cut and coagulate
Bipolar cautery is only used for coagulation and haemostasis
When should electrosurgery not be used?
If the patient is not anaesthetisesd
If there is presence of volatile/flammable gases or liquids
The ground plate for monopolar systems is not in complete contact with the animal
If the power lead is wrapped in a coil around around towel clips
The electodes are not clean
With an innapropriate power setting- keep as low as possible
What forceps are most commonly used for handling tissues?
Thumb forceps
What are the types of thumb forceps?
Toothed- adson, debakey
and Non-toothed
What type of thumb forceps are these?
Adson forceps
What type of thumb forceps are these?
DeBakey vascular forceps
When should non-toothed thumb forceps be used?
When handling inanimate objects- dressings, pathology specimens
Name the three types of tissue forceps?
Allis tissue forceps- jaws traumatic
Babcock forceps- slightly more delicate jaws
Doyen forceps- designed for holding and occluding lumen of bowel
Name these forceps
Allic tissue forceps
Name these forceps
Babcock forceps
Name these forceps
Doyen Forceps
What are the purpose of retractors?
Expose the surgical field with as little trauma as possible
What retractor is this and what are they used for?
Finger held retractors- used for thin or delicate tissue planes
What are hand held retractors used for?
Used for retraction thicker or more robust tissue planes
What is the name of this retractor and what is it used for?
Balfour retractors
Used for abdominal wall retraction, especially in larger animals and for working in the cranial abdomen- central blade can be used to lift the xiphoid process and improve exposure
What is the name of of these retractors?
Gossett retractor- used for abdominal retraction
What is the name and functions of these retractors?
Finochietto rib retractors
Used to seperate the ribs for intercostal thoractomy or the divided halves of the sternum for median sternotomy
What is the name and function of these retractors?
Gelpi retractors
Used to seperate tissues in various locations, the tips are quite sharp so use with caution around delicate structures
Why is suction useful during surgery?
It is the most effective way of removing large volumes of fluid from the wound.
What are the names and function of these suction tips?
Top- Frazier-ferguson
Good for fine work and removint haemorrhage during dissection
Middle- Yankauer
Good for removing large volumes of fluid from body cavities
Bottom- Poole
Good for removing fluid from body cavities and doesn’t block easily
What are the complications of improper tissue handling?
- Tissue ischaemia with subsequent delayed healing or necrosis leading to wound dishiscence, incisional hernias etc
- Dead space leading to seroma and abscess formation
- Wound contamination leading to infection
- Increased postoperative pain
- Poorer cosmetic results
What is suture material selected based upon?
- Tensile strength
- Structure of the suture
- Chemical composition of the suture
- Local wound conditions
- Wound healing rate
What is tensile strength and how do you decide what tensile strength to use?
This is proportional to the diameter of the suture
Use suture with a tensile strength equal to the strength of the tissue
How is metric and USP suture diameter calculated?
Metric- diameter of a suture to tenths of a mm
USP- suture size in arbituary units based on diameter of suture in thousands of an inch
What is the ideal structure of suture material?
Easy to handle
low tissue drag
resistance to contamination
good knot security
What is the difference between monofilament and multifilament sutures?
Monofilament is a single strand of material
Multifilament is multiple strands of suture braided or twisted together
What are the advantages and disadvantages of monofilament sutures?
Advantages
- Little tissue drag
- Withstand contaminatino
Disadvantages
- Prone to damage from handling equipment- breakage
- High degree of memory- gives worse knot security
What are the advantages and disadvantages of multifilament suture?
Advantages
- Easier to handle from less memory
- Better knot security
Disadvantages
- Increased tissue drag
- Increased chance of contamination
- Capillary action
What is the differecne between absorbable and non-absorbable sutures and when would both be used?
Absorbable
- Lose tensile strentgh within 60 days
Non-absorbable
- Retain their strength for more then 60 days
- Used for skin, some hernias, ligament and tendon repairs
What are synthetic and natural absorbable sutures?
Synthetic are made from synthetic polymers and are broken down by hydrolysis
Natural is made from animal or plant material and are broken down by enzymatic degradation causing inflammation and more tissue reaction
What suture should be used in contaminated/infected wounds and why?
Least amount possible of synthetic monofilament
Multifilament may habour bacteria and synthetic gives the least amount of tissue reaction
What suture material should be used for visceral wounds and connective tissues/fascia and why?
Visceral wounds- absorbable as gain tensile strength to support itself after 14-21 days
Connective tissues/facsia- non-absorbable or slowly absorbable as ther heal more slowly
What are the generic features of all needles and what differences affect choice?
Most stainless steel- strong, withstands corrosion and doesn’t harbour bacteria
Needle choice-
long enough to reach both sides
Appropriate diameter for suture
What are the two ways needles are attached to suture?
Swaged on- attached during manufacture- less traumatic (new and sharp)
Eyed needles- re-usable, cheap, need to thread a needle
What are the two shapes of needles?
Straight- used near the body surface or skin held in fingers
Curved needles- used for most suturing and are especially useful for narrow and deep wounds
What is the difference between round bodied and cutting needles?
Round have sharp point that pierces and spreads tissue without cutting. Used for suturing easly penetrated tissue
Cutting needles have two or three sharp cutting edges designes for use in difficult to penetrate tissues
Name these three types of cutting needles based on the followign descriptions:
- Cutting edge along inner (concave) side of the needle. This may cause the suture material to cut out towards edges of incision
- Have cutting edge alonf outer (convex) side making the needle stronger and suture less likely to cut out
- Combination- used for dense/tough fibrous tissue (tendon) and for some cardiovascular procedures
1- Conventional cutting needles
2- Reverse cutting needle
3- Taper cut needle
What are the differences between the three types of needle holders?
Mayo-hagar
- No scissor blade with ratchet
Olsen-hegar
- Scissor blade with ratches
Gillies
- No ratchet arms are different lengths
How short should ends of suture be cut?
Cut the ends of the suture as short as possible without compromising the knot
3mm synthetic sutures
6mm surgical gut
1cm at skin to facilitate removal
How many throws are required for a safe knot?
What are the three suture patterns and what effect do they have on tissue alignment?
Appositional- brindh the wound edges into direct contact and are the most widley used type of suture
Inverting- turn the wound edges inwards
Everting- turns wound edges outwards
What are the advantages and disadvantages of interupted sutures?
Adv-
Easily placed and removed
allow adjustment of tension across a wound
More fail tolerany than continuous
Disadvantages-
Less economic on suture material
What is a vertical matress suture useful for?
It can help to relieve minor tension and is usually alternated with simple interupted, vertical removed 3-4 days post op.
What are the advantages of continuous horizontal?
No sutures to remove in fractious pets
No sutures passing through the skin to cause irritation or track infection into the wound
Minimal scar formation
What difference is there between simple continuous and ford interlocking?
Each loop through the skin is partially locked allowing greater security if the suture breaks- can be fiddly to remove
What suture pattern is commonly used for subcutaneous tissue and why?
Simple continuous or continuous horizontal mattress pattern
Decrease tension across the wound before skin sutures are replaced- reduce dead space and approximate skin edges
What suture pattern is used to close the skin?
Simple interupted, cruciate matress or continuous.
Spacing depends on direction of the skin tension lines and thickness of skin but generally 5-10mm appart
How can staples be more or less expensive then using suture?
Can be more expensive as they cost more then suture material
But if closing larger wounds it can be cost effective
When are staples not suitable?
Wounds that are under tension
Wounds with complicated geometry/uneven edges
Less then 4-6mm depth of tissue seperating them from bone or viscera
When are circular and linear stapling devices mainly used?
Most commonly for hepatic and pulmonary lobectomies and closure of stomach of bowel
How long does it take for cyanoacrylate adhesives to polymerise?
In the presence of moisture- less than 60 seconds (often less then 15)
When are cyanoacrylates useful?
Useful for repairing small skin wounds
Useful if suture removal will be difficult
What are the disadvantages of tissue adhesives?
Low strength
Adhere poorly to moist surfaces
Not suitable for use on mucous membranes, larger wounds or wounds under tension
Why should tissue adhesives not enter wounds?
Cyanoacrylates may cause chronic inflammation and wound infection or granuloma formation
What do these terms mean?:
- tomy
- ectomy
- centesis
- pexy
-tomy
to incise into
-ectomy
to remove or excercise
-centesis
introduction of needle into cavity to aspirate fluir or gas for diagnostic or therapeutic purposes
-pexy
surgical fixation
What do these terms mean?:
- rraphy
- stomy
- desis
- plasty
-rraphy
act of suturing
-stomy
Surgically creating an openning
-desis
secure fixation by surgical methods
-plasty
surgical shaping or moulding of a structure
What are the 6 phases of wound healing?
Lag or inflammatory phase
Repair phase-
Connective tissue repair
Wound contraction
Epithelilisation
Remodelling phase
How long does the lag/inflammatory phase last and what happens?
Lasts 1-5 days
Immediate response to injury is haemostasis
Neutrophils- attracted to wound by chemotaxis- degrade necrotic tissue and control infection by destroying bacteria
Monocytes enter differentiate into macrophages- remove degenerate neutrophils, necrotic tissue and debris by phagocytosis and secrete growth factors
Heat, pain, redness and swelling
How long does the repair phase last and what are the three overlapping parts?
Lasts 6-16 days
Connective Tissue Repair
Wound contraction
Epithelialisation
What happens during the connective tissue repair phase?
- Mesenchymal cells in the wound edges differentiate into fibroblasts
- Inflammatory cells remove necrotis tissue and debris
- New fibroblasts move into wound and create collagenous ECM
- Angiogenesis (capillary ingrowth)
- 7-14d after injury the collagen stabilises- fibroblasts undergo apoptosis and some new capillaries
- Results in granulation tissue- scar
What happens during the wound contraction of the repair phase?
- Begins 5-9 days post injury
- Exact mechanism unclear
- Specialised myofibroblasts containing actin-containing microfilaments appear to proliferate
- Attach to wound matrix and each other and contract
- Contraction continues till wound edges meet or equal tension or rest of skin
What happens during epitheliazation phase of repair phase?
- Partial thickness wounds occurs straight away
- Full thickness requires adequate granulation tissue so 4-5 days late
- Epithelial cells from wound edges and any remaining hair follicles migrate across the wound until they form a monolayer
- Proliferation begins 1-2 days later
- Epithelial layer becomes firmly attached to underlying dermis and stratifies
What happens during the remodelling phase and when does it occur?
Starts 14-16 days post-wounding and lasts 2 weeks to months
- Collagen content and strength of wound increase rapidly first 14-16 days then remodelling begins
- Cellular content of granulation tissue reduces and the collagen bundle reorganizes by thickening, cross linking and reorientating along the lines of tension
- Scar will never be as strong as original tissue- 20% in first 3 weeks, reach 70-80%
What local factors affect wound healing?
Wound perfusion- dividing cells within the healing wound require O2, shock/hypotension/arterial occlusion due to pain slow the healing
Tissue viability- devitialised/necrotic tissue prolong inflammatory phase and delay
Wound fluid accumulation- haematomas or seromas slow healing by physically seperating the tissues and put pressure reducing perfusion
Infection- prolongs inflammatory phase, reduces chemotaxis, increases tissue damage
Mechanical factors- tension, motion and pressure
What happens in skeletal muscle is sarcolemma is grossly disrupted or significant muscle mass lost?
Repair occurs by fibrous union between the ends of the muscle strands
What systemic factors affect wound healing?
Immunosupression
Neoplasia
What is required for successfull healing of intestinal wounds?
Avoiding infection, preservation of blood supply and avoiding tension are critical to healing
Collagenase activity in the wound causes a reduction in wound strength
What happens when a nerve is severed?
The severed ends retract
Cell body swells
Nucleus becomes eccentrically-placed and distal portion of axon undergoes wallerian degeneration
Within 48 hours sprouts from proximal axon attempt to grow down the distal endoneural tube- can be blocked so may split to supply 2 endoneural tubes
What differs about epithelium, endothelium and mesothelium wound regeneration?
Similar mechanisms- rate of healing differs
What is special about liver regeneration?
Can regenerate 70-80% of volume in 6 weeks by proliferation and hypertrophy
What is the 6-8 hour golden period?
Wounds can be closed with minimal intervention because bacteria introduced would take 6 hours to adhere to tissues
Now considered less important- many factors affect the speed (number, tissue, trauma)
What are the 2 main ways wounds are categorised?
Degree of contamination- based on number of bacteria present in the wound
Aeitiology- cause of a wound determined the likely amount of tissue trauma and contamination
What are the different classes of degree of contamination?
Clean- elective surgical wounds not entering the respiratory, urogenital or GI tract with no breaks in asepsis
Clean-contaminated- surgical wounds involving resp, urogenital, gastrointestinal without minor significant contamination
Contaminated- fresh traumatic wounds less then 4-6 hours old, surgical wounds of resp, uro, GI with significant contamination, surgery with inflammation, major break in asepsis
Dirty- traumatic wounds oler then 4-6 hours, contaminated with foreign material, perforation of a hollow viscus, surgery in presence of abscessation
What are the 7 classes of aetiology classed wounds?
Abrasion- partial thickness wound with loss of epidermis and part of dermis
Avulsion- tearing of tissue from its attachments
Degloving- low-velocity avulsion of skin due to rotational forces
Incision- sharp trauma resulting in a smooth-edged wound with minimal tissue trauma
Laceration- sharp trauma resulting in an irregular wound with tearing of tissue and trauma of underlying tissue
Puncture wound- penetratoin of sharp object, often minimal superficial damage with substantial damage to deeper structures, can carry risk to organ systems
Burns
What is the basic treatment plan of wounds?
Convert a wound into a clean or clean-contaminated wound if possible and then close
If this cannot be achieved the wound is managed as an open wound
How should the wound be prepared?
- Take swabs for bacteriology before cleaning the wound
- Prevent further contamination by covering with sterile, water soluble ointment or swabs soaked in saline
- Clip a large area around the wound- start at edges and work away
- Prepare skin around the wound with surgical scrub- do not allow contact to wound
What is hydrodynamic debridment often called and how is it done?
Lavage
Aims
- Decrease bacteria
- Remove debris
- Prevent further contamination
- Prevent transformation of acute clean or contaminated wounds into infected
- Convert contaminated or clean-contaminated wounds to suitable for primary closure
- In grossly contaminated wounds, copious lavage with tap water
- Otherwise perform pressure irrigation with large volumes of isotonic solution- 8psi optimum
- Antiseptics can be added to final not detergents
What does hydromechanical debridment use and what does it do?
Amorphus hydrogel dressings- intrasite gel
Promotes hydration
Autolysis of necrotic tissue
Absorb sloughing tissue
Promote a moist wound site
Prevent eschar formation
Bacteriostatic
What should be done for hydromechanical debridment for wounds containing necrotic tissue?
What sould be done for wounds with lots of exudate?
Cover the hydrogel with a non-adherent semi-occlusive primary dressing layer or an adherent primary layer
This will absorb the hydrogel and act similar to a wet-dry dretting
Lots of exudate:
Cover with hydrocellular foam dressing that will not absorb gel, remove the gel when changing the dressing with lavage, change 1-3 days depending on exudate amount, infected change daily
When is surgical debridment used?
Wounds with extensive tissue trauma or large amount of debris
How is surgical debridment done?
Evaluate viability of tissues based on colour, puls and bleeding
If it can’t due to oedema wait 48-72 hours
Remove all devitalised tissues and foreign material
Preserve muscles, tendons, nerves and blood
Lavage again
What are the treatment plans for the following after debridment:
- Clean/clean contamination
- Contaminated
- Contaminated to dirty
- Unsuitable for closure
- Clean/clean contaminates- primary closure- immediate suture closure without tension
- Contaminated- delayed primary closure- closure 1-5 days after wounding, before granulation bed formation, lavage wile open
- Contaminated to dirty- secondary closure- closure >5 days after injury, exise wound, granulation tissue margin and epitheliliased edges then close
- Wounds unsuitable- second intention healing- no closure- healing by granulation, epithelialisation and contraction
What is the primary larer of open wound managment?
Determinds the dressing’s functin- should be in contact with wound surface to prevent tissue maceration
What are the types of primary laters and when are they indicated?
Adherent dressings- Adhere to wound because fibrinous material, granulation tissue or proteinaceous exudate penetrates and dries
Slow healing by removing surface cells and growth factors, often painful removal and can cause tissue maceration
Non-adherent dressings- indicated for most wounds
What factors determind the type of non-adherent dressing to use?
- What you want the dressing to do- a hydrogel for debriding necrotic tissue, no gel if you want to speed up granulation tissue formation
- How much exudate the wound is producing- non-adherent allow drainage to intermediate layer but retain sufficicent moisture to prevent desication
- Is the wound infected- change the dressing at least once a day as bacteria will multiply in moisture layer, remove and lavage
Name 9 non-adherent dressings
- Calcium alginate
- Fenestrated polyester film dressings
- Hydrocellular foam dressings
- Hydrocolloid dressings
- Polyethylene/polyurethane film dressings
- Petrolatum-impregnated gause
- Hyperosmolar agents
- Maggots
- Silver dressings
What do caclium alginate dressings do?
Absorb exudate and water on contact with wound surface forming non-adherent gel.
Extremely absorbent, can be left for upto 7 days on non-infected wounds.
Enhance autolytic debridment
Indicated for full or partial thickness wounds at any stage of healing with moderate to heavy exudation
What do fenestrated polyester film dressings do?
e.g melolin, telfa pads, release pads
Polyester film stops dressing adhering to tissues
Mainly used for protecting wounds with an intact epithelial surface e.g surgical wounds closed primarily
What do hydrocellular foam dressings do?
e.g ellevyn
These are extremely absorbent but do not transmit liquids to the secondary layer
Widely used and available in a variety of forms
Especially good on ulcers
What do hydrocolloid dressings do?
e.g Granuflex, tegasorb
Composed mainly of cellulose that absorbs moisture and exudate, becomes a gel, creates a barrier to bacteria
Promotes autolytic debridment
Can handle a wide ranfe of exudate volumes
What do polyethene/polyurethane film dressings do?
e.g opsite flexigrid, tegaderm
Non-absorbent but some pass water vapour into secondary layer
Typically left on longer than more absorbent or permeable dressings
Indicated for protection of wounds with an intact epitithelial surface (sutured, cathether)
What do petrolatum-impregnated gauze dressings do?
May slow epithelialisation so contraindicated for wounds in the later stages of repair
Non-absorbent and hydrophobic due to petrolatum gel
Mainly used for protecting wounds with an intact surface but fragile epidermis
What do hyperosmolar agent dressings do?
Commercial manuka honey dressings and home-made sugar dressings are hyperosmolar and dehydrate bacteria, impairing their growth
Honey may contain inhibitory substances like hydrogen peroxide and inhibins and its low pH reduces bacterial growth
What do maggots do in dressings?
Larvae of Lucilia sericata are sometimes used for wound debridment
Gettinf the containment dressing to stay in place can be difficult
Preventing patient interference can also be hard
May become more useful as antibacterial resitance increases
What do silver dressings do?
Release bactericidal silver ions into the wound
What is the purpose of the secondary layer in open wound managment?
Draws away and absorbs excess fluid, keepinf the primary layer in contact with the wound
Obliterates dead space by providing pressure and protects the wound by padding, supporting and immobilizing it.
Splints may be included in this layer
Types include: cast padding, absorbent pads, cotton wool
If the intermediate layer is not thick enough it may become saturated and need replacing.
What is the purpose of the tertiary layer in open wound managment?
Secures the rest of the dressing, provides some pressure and supports and keeps the other layers clean.
If dressing is too lose it may slip and cause maceration if the primary layer loses contact with the wound, if too tight may compromise circulation
How is too greater pressure avoided from the teritary outer later?
Use a thick enough secondary layer
Even distribution of tension
Estimating pressure with a finger placed underneath the bandage
Monitoring the patient after the bandage has been applied
