Wounds Flashcards
Mechanical debridement of wounds consist of
Wet-to-dry, wet-to-wet dressing, manual debridement with gauze or irrigation
Best choice of suture for closure of contaminated wounds
Totally not sure about this one. A monofilament absorbable suture - Monocryl? But PDS if under a lot of tension
Most important factor in management of contaminated/Infected wounds
Removal of devitalised tissue
Granulation tissue consist of
Collagen (type III), capillaries, fibroblasts
Describe the phases of wound repair
Inflammatory: Haemostasis and inflammation Tissue Formation: Angiogenesis, Fibroplasia, Tissue Formation, Epithelialisation, Contaction Remodelling/Maturation: Replacement of hyaluronan in provisional cellular matrix with proteoglycans in extracellular matrix Alignment of collagen fibres Gain in strength of wound
2 main cell types in wound healing inflammatory phase
Platelets and neutrophils
Differences between low and high pressure lavage in wound irrigation
Low pressure lavage is ideal; 10-15psi. Can used 35ml syringe with 19 gauge needle, holes punched in the top of a saline bottle. Encourages debris and bacteria to wash away from the wound High usually uses a single water jet. pressure lavage is bad: eg. WaterPik. Causes more tissue trauma and may force debris/bacteria further into tissues. However, this can be utilised in circumstances, such as abdominal lavage
What are the 3 purposes of drains
Facilitate elimination of dead space Evacuate existing fluid and gas accumulation Prevent anticipated formation of fluid collections
What are the advantages and disadvantages of penrose drains?
Advantages: Economical Can be used in lots of situations Disadvantages May kink Not useful in body cavities Passive only, no suction possible
What are the advantages and disadvantages of Jackson-Pratt drain
Advantages: Closed or open system Excellent for body cavities Less reactive Disadvantages: Attaching container can be difficult depending on location
What locations should be used to drain a) fluid and b) air from the thorax?
a) Ventral (2 inches above elbow) 7th intercostal space (front of rib) b) Dorsal 12th intercostal space (front of rib)
What complications can occur with drains
Foreign body response Ascending infections Portion of drain left in wound Loss of function/blockage Linkage of drain Suture dehiscence Damage to vessels and nerves
Which dressings can be used for heavily infected wounds?
Hypertonic saline dressing Honey Antimicrobial dressing Should use surgical debridement first
What are the advantages of calcium alginate dressings?
Calcium in dressing interacts with sodium in wound, providing wound exudate, stimulating fibroblasts and epithelial cells and speeds wound homeostasis Calcium modulates epithelial cell proliferation and migration Conform, vertical wicking, good for moderately to heavily exudative wounds Can moisten if insufficient exudate Change 3-7 days so fewer chances for contamination and reduced cost
Define bacterial contamination, colonisation and infection
Contamination: Bacteria without multiplication or trauma to host Colonisation: Attached to tissue and multiplying but not causing trauma to host Infection: Bacteria invade healthy tissue and multiply, overwhelming host’s response
What are the four classes of wound?
Clean: Surgical and do not involve resp, GI or urogenital Clean contaminated: Surgical with lumen of resp, GI or urogenital Contaminated: Traumatic, gross contamination, necrotic debris Infected: Large numbers of bacteria, inflammation, edema, suppuration
What is a keloid?
Similar to hypertrophic scar but extends beyond original wound margin and rarely regresses. May be due to increased number of epidermal Langerhans’ cells. Treatment: Steroid injection, surgical excision, radiation therapy, compression and tension reduction used
Name 3 tension relieving suture patterns
Horizontal Mattress Far-near-near-far Walking suture
Describe a V-Y Plasty
V-shaped incision with the point of the V directed away from the defect to be closed Close the original defect Close V incision by converting it to a Y Longer legs of the V make a greater degree of tension relief Use for eyelid scar revision and closing elliptical defects
What is a method of closing a circular skin defect
a.Suture along relaxing skin lines of tension then remove dog ears b. Convert to X or Y c. Excise 2 triangles on opposite sides, creating a fusiform defect; height of triangle should be equal to dimeter of the circle; removes skin of 1.5x original defect d. Double S-shaped incision with bi-winged excision e. Bow tie f. Combined V incision
Describe a bipedicle flap
Single longitudinal incision parallel to defect, or one incision on each side Skin flaps approximately same width as original defect Two sources of blood supply remain Burrow’s triangles can be used to help with excess laxity/dog ears Original defect is closed New incision(s) are left open
What is the difference between a rotation flap and a transposition flap
Rotation flap: Create semicircular incision and move tissue laterally to cover defect Transposition flap: Rectangular, single pedicle flap created adjacent to defect and rotated on it’s pedicle. Can be rotated up to 180 degrees but rotation shortens flap
What are the 3 purposes of drains
Facilitate elimination of dead space Evacuate existing fluid and gas accumulation Prevent anticipated formation of fluid collections
What are the advantages and disadvantages of penrose drains?
Advantages: Economical Can be used in lots of situations Disadvantages May kink Not useful in body cavities Passive only, no suction possible
What are the advantages and disadvantages of Jackson-Pratt drains
Advantages: Closed or open system Excellent for body cavities Less reactive Disadvantages: Attaching container can be difficult depending on location
What locations should be used to drain a) fluid and b) air from the thorax
a) Ventral (2 inches above elbow) 7th intercostal space (front of rib) b) Dorsal 12th intercostal space (front of rib)
What complications can occur with drains
Foreign body response Ascending infections Portion of drain left in wound Loss of function/blockage Linkage of drain Suture dehiscence Damage to vessels and nerves
Which dressings can be used for heavily infected wounds
Hypertonic saline dressing
Honey
Antimicrobial dressing
Should use surgical debridement first
What are the advantages of calcium alginate dressings
Calcium in dressing interacts with sodium in wound, providing wound exudate, stimulating fibroblasts and epithelial cells and speeds wound homeostasis
Calcium modulates epithelial cell proliferation and migration
Conform, vertical wicking, good for moderately to heavily exudative wounds
Can moisten if insufficient exudate
Change 3-7 days so fewer chances for contamination and reduced cost
Define bacterial contamination, colonisation and infection
Contamination: Bacteria without multiplication or trauma to host
Colonisation: Attached to tissue and multiplying but not causing trauma to host
Infection: Bacteria invade healthy tissue and multiply, overwhelming host’s response
What are the four classes of wound
Clean: Surgical and do not involve resp, GI or urogenital
Clean contaminated: Surgical with lumen of resp, GI or urogenital
Contaminated: Traumatic, gross contamination, necrotic debris
Infected: Large numbers of bacteria, inflammation, edema, suppuration
What is a keloid
Similar to hypertrophic scar but extends beyond original wound margin and rarely regresses. May be due to increased number of epidermal Langerhans’ cells.
Treatment: Steroid injection, surgical excision, radiation therapy, compression and tension reduction used
Name 3 tension relieving suture patterns
Horizontal Mattress
Far-near-near-far
Walking suture
Describe a V-Y Plasty
V-shaped incision with the point of the V directed away from the defect to be closed
Close the original defect
Close V incision by converting it to a Y
Longer legs of the V make a greater degree of tension relief
Use for eyelid scar revision and closing elliptical defects
What is a method of closing a circular skin defect
a. Suture along relaxing skin lines of tension then remove dog ears
b. Convert to X or Y
c. Excise 2 triangles on opposite sides, creating a fusiform defect; height of triangle should be equal to dimeter of the circle; removes skin of 1.5x original defect
d. Double S-shaped incision with bi-winged excision
e. Bow tie
f. Combined V incision
Describe a bipedicle flap
Single longitudinal incision parallel to defect, or one incision on each side
Skin flaps approximately same width as original defect
Two sources of blood supply remain
Burrow’s triangles can be used to help with excess laxity/dog ears
Original defect is closed
New incision(s) are left open
What is the difference between a rotation flap and a transposition flap
Rotation flap: Create semicircular incision and move tissue laterally to cover defect
Transposition flap: Rectangular, single pedicle flap created adjacent to defect and rotated on it’s pedicle. Can be rotated up to 180 degrees but rotation shortens flap
State the advantages and disadvantages or polyglactin 910 and polydioxanone
Polyglactin 910:
- Advantages:
- Good size to strength ration
- Greater initial breaking strength and stiffness than polyioxanone
- Minimal tissue reaction
- Excellent handing
- Disadvantages:
- May cut through friable tissue (esp. if not coated)
Polydioxanone:
- Advantages:
- Maintains tensile strength over prolonger period
- (Less memory than polyglyconate)
- Disadvantages:
- Moderate knot security
- Moderate handling
What suture material should be used in the urinary tract
Polyglyconate or polydioxanone (if likely to be exposure to urine)
Poliglecaprone possible but not yer evaluated
List the reasons for graft failure
Infection
Fluid accumulation
Motion
Inflammation
Define serum imbibition and inosculation
Imbibition: Newly applied graft nourished by plasma-like fluid that passively enters open vessels of graft via capillary action
Inosculation: After 48hrs, new capillaries generated in recipient bed traverse fibrin layer to anastomose with those if graft
Where can grafts be taken from
Full-thickness sheet grafts: Pectoral region
Split-thickness sheet grafts: Ventral abdomen and ventrolateral thorax behind elbow
Island grafts: Ventrolateral abdomen, perineum, area beneath mane
What is the Modified Meek grafting technique
A combination of split-thickness sheet grafting and island grafting. Split-thickness sheet graft obtained and Meek micrografting equipment converts this to many micr grafts on a piece of gauze
How should grafts be stored
Lay on sterile gauze swab with epidermis next to gauze
Roll up gauze-graft with gauze outside of roll
Place in sterile container with 1-1.25mL of storage medium per cm2 of graft
Check pH indicator: Cherry red to orange-yellow indicates excessive catabolites (apply graft or replace half of medium)
Can usually store until wound permits grafting
Name and define the types of septic arthritis/osteomyelitis in foals
S-Type Infections:
Synovial membrane and fluid
foals <1 week
Multiple joints, most commonly stifle and hock
Acute lameness
Linked with FPT
E-Type Infections:
Articular epiphyseal complex (source of growth)
Several weeks of age
Multiple or single joints
Linked with FPT
May also have pneumonia/diarrhea
P-Type Infections:
Physis
+/- joint involvement
Weeks to a few months of age
Healthy foals
Distal physes of MCIII/MTIII and tibia common
One site usually
Streptococcus, Rhodococcus, Actinobacillus, E. coli, Salmonella
What are the most common bacteria found in septic joints in foals and adults
Foals, type P: Streptococcus, Rhodococcus, Actinobacillus, E. coli, Salmonella
Adults after Injection/surgery:
Staphylococcus spp.
Traumatic injury:
E.coli (most common)
Salmonella (most common)
Staphylococcus
Pseudomonas
Yeast
Other fungi
What are the methods of local antibiotic delivery
IO
IA (+/- pump)
RLP
Antimicrobial infused biomaterials
What biomaterials can be used in local antibiotic delivery and define whether the are absorbable or non-absorbable
Biodegradable:
Collagen sponge
Plaster of paris
Hydroxyapatite
Dextran gel
Non-biodegradable:
PMMA
How do you treat implant infections
Local AB delivery:AB beads:
PMMA good elution but non-absorbable (remove but rarely cause problem if left)
RLP:
Daily for as long as possible
Whole systemic daily dose
Large vessels, immediate compression, topical NSAIDs, Bandaging
Drainage of infected tissues:
Ultrasound guided incision
Surgical drain
Remove implants when sufficiently stabilized
If not sufficiently stable:
Remove implants, debride bone and replace autoclaved implants
Remove and manage fracture/arthrodesis with transfixation cast
Dynamic compression or tension device can restabilize site; empty screw holes filled with AB-impregnated collagen/dextran gel, POP
What is the ethology of dentigerous cysts
Incomplete closure of first branchial cleft during embryologic development
List the treatment options for sarcoids
Surgical Excision:
Least successful alone
Recurrence: 15.8-82%
Laser Ablation:
Less spread of cells
Recurrence: 38%
Combine with chemotherapy
Cryotherapy:
Success: 60-100%
Recurrence: 91% (success 9%) in another study
Thermocouples help
3x -30 degrees: Success: 68% to 85% if treatments repeated
Hyperthermia:
Spontaneous regress of non-treated tumors also
Radiotherapy:Iridium-192 implants
Success: 87.5-100%
Single dose
Brachytherapy: 86.6%
Hair/pigment loss, fibrosis, cataract formation, corneal ulceration
Gold-198 implants
Expensive
Hospitalization
Potentially hazardous
General anesthesia may be needed
Immunotherapy:
Mycobacterium cell wall extracts
Live whole-cell bacille Calmett-Guerin (BCG)
Propionibacterial cell wall extracts
Stimulated cell-mediated immuniting
Multiple intralesional injections
Higher success for smaller tumors
Severe local tissue swelling
Anaphylactic shock possible
Spontaneous regresson of untreated tumors can occur
Recurrence: 0-40%
Vaccination (tumor tissue) successful
Intralesional Cisplatin:
Success: 87%
Recurrence: 66%
Avoids systemic toxicity if in oil
Epinephrine can be added to emulsion (1:1000)
1mg cisplatin per cubic centimeter, minimum 4 treatments
Cytoreduction may help; injection does not affect wound healing
Intralesional TNF + xanthate successful
Topic Application of Chemotherapeutics:5-fluorouracil (5-FU):
Daily treatment
Success: 66%
AW3-LUDES
AW4-LUDES:
Success: 35%
Scarring occurs
Avoid eye
Bloodroot and zinc
Spontaneous regression of untreated tumors
Autogenous tumor vaccine (11/12 success)
If large, aggressive tumor, recommend combination of modalities:
Excision/laser ablation + chemotherapy/radiation therapy
What are the treatment options for cutaneous habronemiasis
May resolve with cooler weather
Ivermectin (kill larvae but do not resolve skin lesion); oral ivermectin may increase pruritus
Large masses may require cytoreduction
Inralesional corticosteroids
Topic organophosphates or bandaging may prevent reinfection
Organophosphates, corticosteroids, DMSO, nitrofurazone have been used together
Ophthalmic form: oral ivermectin, topic corticosteroid eye drops (check cornea first), curettage
What are the histologic feature of mast cell tumours
Benign, solitary, nodular cutaneous form is most common (inflammatory reaction to dysplastic mast cells and recruited eosinophils and granuloma develops)
Malignant (abnormal mast cells with increased nuclear-to-cytoplasmic rations, anisokaryosis and increased mitotic figures) and congenital forms possible
What are the types of melanoma
Melanocytic nevi:
Large pleomorpic melanocytes with increased mitotic figures, binucleate cells and variable cytoplasmc pigmentation, single/multiple discrete nodules in grey and non-greys
Dermal melanomas:
Benign. Homogenous dendritic cells with condensed chromatin, dense pigmentation but no mitosis. Originate in deeper dermis, small single/multiple nodlues
Dermal melanomatosis:
Benign. Confluent multiple large melanomas. Risk increases with age. Risk of metastases
Malignant melanomas:
Rare. Invasive, poor prognosis
Which structures can be affected in a heel bulb laceration
Skin
SubQ
Hoof wall
DFTS
DDFT
Navicular bursa
Navicular bone
Palmar cartilages
DIP jt
SDFT
Collateral suspensory ligaments of naivuclar bone
P3
Name 3 nasty things that can occur with axillary lacerations
SubQ emphysema
Pneumomediastinum
Pneumothorax
How is the proteolytic activity of chronic wound fluid different from acute wound fluid
Urokinase-type plasminogen activator and urokinase-type plasminogen activator receptors active in chronic wounds (plasminogen activator in acute wounds)
What are differential diagnoses for chronic non-healing wounds
FB
Sinus tract
Fistula
Sequestrum
Infection
Sarcoid
Habronemiasis
Pythiosis
Other tumor
What is the difference between a sinus tract and a fistula
FISTULA
Abnormal communication between two internal organs or from organ to body surface:
Synovial fistula
Enterocutaneous or parietal fistula
Orocutaneous or esophageal fistula
SINUS TRACT
Cavity or channel:
Normal, eg. Venous sinus
Pathologic, eg. Channel permitting escape of pus through skin
Define creep (in relation to skin, not a person ) and what are the 2 types of creep?
Stress constant and strain increases with time
Mechanical creep:
Biomechanical property of skin, allowing it to stretch beyond it’s normal limits of extensibility under constant load
Straightening of collagen fibers parallel to stretching force
Biological creep:
Skin increases area by increasing epidermal mitotic activity, upregulation of blood vessels and increasing dermal cell numbers
Tissue expanders, hernias, subcutaneous masses
Define relaxation
Strain constant and stress decreases with time
What is the minimum distance from the skin edge of a traumatic wound that skin sutures should be placed?
0.5cm
Which is preferable: Increasing suture number or suture material size?
Increasing suture numbers
What are the advantages and disadvantages of simple interrupted sutures?
Advantages:
Excellent tissue apposition
Can vary width if irregularly shaped wound
Can adjust tension on individual sutures
Greater tensile strength and less compromise of microvasculature than simple continuous patterns
Can combine with other patterns
Disadvantages:
Placement too far back or too much tension leads to to inversion
What are the advantages and disadvantages of simple continuous sutures?
Advantages:
Quick
I would add that in line alba this is stronger but Auer didn’t list this
Disadvantages:
Knot failure or suture breakage results in breakdown
Cannot vary tension
Increased edema
Compromised circulation
Prolonged inflammatory phase of wound healing
Lack of precise apposition
