What is de-gloving?
A type of laceration, in which skin is sheared from underlying fascia by rotational and/or crushing forces This may result in skin ischaemia, as the feeding blood vessels are torn. Often the external appearance of the wound may be relatively minor, despite the major underlying damage. This type of injury is most often caused when a limb is caught beneath a vehicle wheel.
What is an avulsion injury?
An avulsion injury involves tearing or forcible separation of a structure from its origin, e.g. the traumatic avulsion of a digit in machinery.
What is a haematoma?
A haematoma is an accumulation of blood within a tissue, organ, or space, which clots and forms a solid swelling. The natural history of a haematoma is a cycle of clotting and liquefaction, followed by gradual re-absorption. Haematomas can cause discomfort, and compress underlying or overlying structures - e.g. a haematoma in the soft tissues of the pretibial region of the leg can lead to pressure necrosis of the overlying skin, and therefore must be decompressed. Haematomas also provide an ideal culture medium for various organisms, and thus increase the risk of a wound becoming infected.
What is the difference between a sinus and a fistula?
A sinus is a blind track, lined by granulation tissue, leading from an epithelial surface into the surrounding tissues. A fistula is an abnormal connection between two epithelially-lined surfaces e.g. gut and skin (see diagram). Both may be either congenital or acquired.
What are the main steps required for the management of any wound?
- Wound inspection +/- wound exploration
- Wound lavage - washout with copious quantities fluid e.g. 0.9% Saline
- Wound excision - excision of unhealthy or devitalised tissue e.g. the edges of a laceration, which will have a compromised blood supply
- Wound closure - there may be some delay between steps 1-3 above, and eventual wound closure
Draw the wound ladder that is used to determine what type af treatment you would use to manage a wound (plastic surgery ladder)?
Stepwise approach to closing wounds
What is primary suturing?
Primary suture involves bringing skin edges together with sutures at the time of initial wound assessment. Delayed primary suture is suturing of the wound at a later date, following steps 1-3 of wound management.
What is healing by secondary intention?
If the wound edges are not brought together by suturing, the wound will still heal, however, the process may be prolonged, and an unsightly scar may result.
What is a split thickness skin graft?
Skin graft which consist of epidermis and variable amounts of dermis
What are characteristic of a plit thickness skin graft?
- Donor site will heal by granulation
- Large available donor area
- Use of meshing can mean large areas can be covered
- Contract more than full-thickness grafts
- Poorer colour match to surrounding skin
What is a full thickness skin graft?
Consist of entire dermis and epidermis
What are characteristics of full thickness skin grafts?
- Donor site requires closure
- Limited size of graft
- Contract less than split-thickness grafts
- Generally a better colour match to surrounding ski
Describe the process of healing of a skin graft
Initial adherence of the graft is a result of fibrin deposition. This is gradually replaced by collagen. The process by which a graft receives a new blood supply is debatable; however it must involve vessel ingrowth from the graft recipient site. Therefore, graft "take" is likely to be influenced by factors affecting adherence or vascularisation. For this reason, skin grafts cannot be used on the following sites:
- Bone stripped of periosteum
- Tendon stripped of paratenon
- Cartilage stripped of perichondrium
- Exposed metalwork
- Open joints
What factors can lead to graft failure?
- Fat as a graft bed
- Excessive mobility of area to be grafted
- Haematoma beneath the graft
- Gross bacterial contamination
What is a tissue flap?
A flap is a transferable block of tissue that may or may not include skin, which has its own blood supply. Flaps are used to reconstruct defects when either the recipient area has an insufficient blood supply of its own to allow healing by a technique such as skin grafting, or when some characteristic of the tissue transferred is desirable e.g. skin colour match for reconstruction of facial defects.
What is essential when using a tissue flap?
There is an identifiable feeding artery and draining vein.
Where does skin recieve blood from?
What is the vascular response in wound healing?
Vasoconstriction, activation of clotting cascades, and platelet activation. This aims to ultimately stop bleeding, by the production of a fibrin clot. Platelet degranulation also has a role in attracting other cells involved in the healing process to the site of injury.
What is the inflammatory response involved in wound healing?
Release of inflammatory mediators has various local vascular effects and attracts inflammatory cells. Local capillaries become more permeable, and cells can move from the bloodstream to the injured tissue. Scavenger cells migrate to the area to remove any foreign or devitalised material.
What is the cellular response involved in wound healing?
This aims to epithelialise and close defect with scar tissue. Fibroblasts produce collagen, which becomes organised into scar tissue. With time, the width of the wound is reduced by the contraction of myofibroblasts. Such wound contraction is usually beneficial, and results in the thin line that most people imagine when thinking about a scar.
How long can it take scars to fade?
6 months - 2 years
What are hypertrophic scars?
Scar tissue raised above the normal level of the scar
- Scar tissue stays within the original scar boundaries
- Scar often red in appearance
- Often resolve with time
How would you manage a hypertrophic scar?
- Massaging the scar
- Sustained pressure on the area
What are keloid scars?
A type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation tissue (collagen type 3) at the site of a healed skin injury which is then slowly replaced by collagen type 1
What are characteristics of a keloid scar?
- Scar tissue extends out with the boundaries of the original scar
- Surrounding normal tissue involved
- Excision usually leads to recurrence
What are the most common sites for keloid scars?
Pre-sternal, deltoid regions, and the earlobes
Who is most at risk of developing Keloid scars?
- African/Afro-Caribbean/African-American origin
How would you manage someone with a Keloid scar?
- Steroid injection
- Silicon massage
- Excision + radiotherapy = last resort
What are naevi?
A concentration of melanocytes in the epidermis
What are characterstics of naevi?
- The number of naevi tends to increase from early life
- The average adolescent will have between twenty and forty
- Tend to disappear in later life
Are naevi malignant or benign?
Can be pre-malignant
What is Bowen's Disease?
The lesions represent areas of squamous cell carcinoma (SCC) in-situ - that is, SCC contained within the epidermis, and not spread beyond the basement membrane. If left untreated, invasive SCC may result.
How would you manage Bowen's Disease?
- Topical chemotherapeutic agents
- Photodynamic therapy
What are Marjolin's ulcers?
SCC's that arise in old scars, particularly in burns scars. As a scar contains no blood vessels, the lesions are slow-growing, and as long as they remain limited to the scar, they do not metastasise.
Where is squamous cell carcinoma in-situ normally found?
75% of these lesions are found on the legs of women over the age of 60 years.
What is a major cause of impaired wound healing?
What are risk factors for pressure sores?
- Improper nutrition
- Impaired sensation
What are common sites for pressure sores to occur?
- Sacral + ischial tuberosities
What is a stage 1 pressure sore?
What is a stage 2 pressure sore?
Partial thickness loss of epidermis or dermis
What is a stage 3 pressure sore?
Full thickness skin loss plus subcut tissue involvement
What is a stage 4 pressure sore?
Full thickness skin loss plus inolvement of muscle/bone/tendon/joint
How would you manage a pressure sore?
Basic Wound management
Facilitate wound healing
- Vacuum dressing
- Nutritional supplementation
Draw a table outlining the different features of venous, arterial, and diabetic foot ulcers and pressure sores. Use the headings:
- Clinical features
What is the pathophysiology of venous ulcers?
Blood stasis causes back pressure
What is an important prophylactic treatment think about giving in someone with a wound?
If someone had a wound from a human bite, what would you want to investigate for after treating the wound?
Blood borne viruses - HIV, Hep B/C etc.