Basic plastic surgery techniques and principles: Chronic wound management
In the sixth part of our series, Aroushka L James and
explain Ardeshir Bayat the management and treatment of chronic wounds
Visit any hospital in any country and many patients
are likely to have chronic non-healing wounds. For example, in the United
Kingdom the cost to the NHS of treating these patients is
vast-estimated at £1000m ($1700m €1400m) a year.w1Of course, this estimate does not take into account the effect on the patient's quality of life.
The healing process
Healing is a highly complex process. The ordered
sequence of events can be described as four key stages-thrombus
formation, inflammation, cell proliferation and repair of the matrix, and
epithelialisation and remodelling of scar tissue.w2
In a chronic wound, this order has become deranged,
disrupting the sequence at one or several of the stages.w3 This may be
because of defective remodelling of the extra cellular matrix, failure to
re-epithelialise, or prolonged inflammation.w4
Types of chronic wound
Pressure ulcers
Pressure ulcers are a potentially avoidable type of
chronic wound. They occur when soft tissue is compressed between a bony
prominence and an external surface for a prolonged period of time producing
a localised area of tissue necrosis. Intervention should be taken at the
first signs of redness over a bony prominence or slightest skin break. But
to prevent this from happening in a hospital setting, medical staff should
implement a turning schedule to avoid prolonged compression.
KARI LOUTNATMAA/SPL
MRSAA under a microscope
Venous ulcers
Venous ulcers are the result of sustained venous
hypertension in the superficial veins. Hypertension in the superficial
veins occurs when valves in the deep perforating veins become incompetent
or it may occur after a deep vein thrombosis. The increased pressure in the
veins causes extravasation of fibrinogen, which leads to deposition of
fibrin around the vessel. This in turn results in poor oxygenation of
the surrounding skin.w5
Treatment of venous ulcers must include ongoing
management of the venous hypertension if the ulcer is to resolve. Failure
to manage this adequately contributes to the high recurrence rate of venous
ulcers.
Arterial ulcers
Arterial ulcers occur as a result of arterial disease.
They arise when inadequate perfusion of skin and subcutaneous tissue at
rest (arterial insufficiency) leads to cell death.w6 Because arterial
disease is usually always progressive, arterial ulcers are also usually
progressive. This means clinicians should diagnose and treat arterial
insufficiency as soon as possible to avoid further tissue loss. Dressings
aim to keep the wound bed moist to prevent additional necrosis. However,
treatment of arterial wounds is largely unbeneficial until an adequate
blood supply is achieved.
Diabetic ulcers
Diabetic ulcers commonly occur on the feet due to
peripheral neuropathy and peripheral vascular disease, which both lead to a
lack of protective sensation, and so a minor wound may lead to an ulcer. To
avoid diabetic ulcers, doctors should treat vascular disease, recommend
appropriate footwear, and implement strict diabetic control.
Assessment and management
Achieving a healed wound is not as simple as many
people expect. Wound care is becoming a multidisciplinary
collaboration between the patient, general practitioner, district
nurse, dietician, physiotherapist, and hospital staff. A chronic wound can
be incredibly disfiguring, malodorous, and detrimental to quality of life.
Clinicians should be aware of the psychological impact of scarring, and
some patients may require the services of body image counsellors.
Education, support, and selection of treatment affordable to the patient
aid compliance and are more likely to result in a healed wound. If
patients' needs are considered and taken into account, whether the
wound completely resolves or not, the treatment will have been a success.
Continuous wound assessment and good observation
allows clinicians to ascertain whether the wound management is effective,
and allows them to monitor for complications. The most advanced techniques
in wound care will fail if they are not applied appropriately, and this
ultimately relies on the observation and how this is recorded.
Wound history
Clinicians should ask the following questions:
- What are the
causes? Can they be removed? For example, if a foreign body such as glass
is present in the wound this delays healing and needs to be removed
- How long has the
wound been there? Commonly wounds fail to heal if the treatment is
incorrect
- Has the correct
diagnosis of the wound been made? Often a lack of experience leads to
misdiagnosis of the wound state and hence incorrect treatment
- Have there been
previous non-healing wounds? What treatments were used? Were they
successful?
- Is the wound
recurrent? Causes of recurrence should be sought and addressed.
Wound examination
Recording wound characteristics allows the clinician
to assess the effectiveness of treatment and minimise complications. They
can then adapt the management plan to suit the changing wound state. The
following information should be recorded in patients' notes.
Location
Wound location gives clues about the cause of the
wound-for example, pressure ulcers are commonly found in sacral
regions-but also the type of dressing that may be required.
Wound mapping
By tracing the margin of the wound on to acetate and
measuring the depth with a sterile ruler, the clinician can make an
estimation of the area and volume of the wound.
Colour
Colour of the wound bed gives an indication of the
phase of healingw7
- red or purple
indicates granulation tissue
- yellow is
fibrous tissue or necrotic slough
- black is eschar
or necrotic tissue
- pink or purple
means re-epithelialisation has begun.
Odour
Malodorous wounds are commonly associated with
infection. Malodour can also be due to poor hygiene or from a dressing that
has not been changed regularly. It is important to note change in
characteristics of the smell, especially if it has become much stronger.
Necrotic tissues give off an offensive repulsive odour, and anaerobes
typically produce a distinctive acrid or putrid odour.
Infection
Infection is the single most important cause of delayed healing.w8 The presence of bacteria in the wound, however, does not indicate infection or that it will impair healing. Studies suggest that low numbers of certain bacteria stimulate healing.w9 But when the number of bacteria becomes too great, the healing process becomes impaired. The continuous presence of virulent bacteria can lead to massive continued inflammatory response that contributes to host injury.w10 Signs of infection should be looked for at each dressing change. These include redness, tenderness, warmth, odour, discharge, and swelling. Typically, Pseudomonas gives a blue-green hue to the wound bed, and anaerobes give a dull appearance. Wounds with a gelatinous texture that bleed easily sare also likely to be infected.
Topical antimicrobial agents are available for local infection. But their use should be weighed up against the risks, allergic reactions, and potential slowing of wound healing. Prolonged use of topical antimicrobials is not advised. If the infection has spread beyond the wound margin or the ulcer probes the bone, systemic antibiotics should be used.
Methicillin resistant Staphylococcus aureus (MRSA) is commonly found in ulcers. Its presence in wounds rarely leads to death, but cross infection into an immunocompromised patient can be fatal. Clinicians should screen for this pathogen in chronic wounds by culturing wound swabs for bacteria, and routinely include this in the management plan.
EAMONN McNULTY/SPL
A necrotic,ulcerated foot
Exudate
The volume of exudate is difficult to measure. A rough estimate should be recorded-no exudate, moderate, or excessive.
The type can be described as
- Serous-clear fluid without blood pus or debris
- Serosanguinous-thin, watery pale red to pink fluid
- Sanguinous-bloody, bright red
- Purulent-thick, cloudy, yellow, or tan.w6
Stage
Staging by clinical examination and assessment allows the clinician to record and evaluate the extent of tissue loss. It also will indicate the appropriate dressing type or whether the wound needs packing. Staging is limited, is unable to show the wound's progression over time, and should not be recorded in isolation. Staging is a valuable tool in wound assessment.
Pain
The patient may feel temporary pain during debridement or dressing changes, although excessive pain at this time should prompt re-assessment of wound care products or technique. Continuous pain is a cause for concern and should be investigated. It is usually due to infection or unsuccessful treatment of the underlying cause, such as ischaemia. Wound pain can be treated with analgesia or support of the tissue during dressing changes.
General patient assessment
General patient assessment can help to avoid a delay in healing. A wound that is poorly vascularised or flooded with oedema will not heal.w11 The resultant poor oxygenation leads to impaired leucocyte activity, decreased production of collagen, and decreased epithelialisation.w3 Wounds of the lower limb are particularly susceptible to poor blood supply.w8
One important cause of non-healing wounds is patient immobility and this should be assessed as pressure ulcers may occur. The Waterlow risk assessment score is a useful tool to assess risk of pressure ulcer development.
An often overlooked, easily treatable cause of non-healing is poor nutrition. Low dietary protein will result in delayed formation of granulation tissue, and vitamin C deficiency inhibits collagen synthesis.
Poorly controlled metabolic disorders such as diabetes mellitus are associated with poor wound healing.w12 Measures to control blood glucose are therefore included in the management plan. Glucocorticoids, non-steroidal anti-inflammatory agents, and immunosuppressive drugs all have well documented anti-inflammatory effects that may slow healing.
The patient's anxiety should be appreciated when assessing. Research has shown that increased anxiety is associated with delayed healing.w12 If anxiety is suspected, doctors have a duty to determine why and try to resolve it.
Wound investigations
Biopsies are not usually done on all wounds, but a longstanding non-healing wound must be biopsied, as the underlying cause could be a skin malignancy.
Goal setting
The purpose of the wound and general assessment is to set a goal for healing the wound. Goal setting allows both clinicians and patient to assess how the wound is progressing and guides decision making in its treatment. The goal should be realistic; unrealistic goals lead to patient dissatisfaction. It may not be a healed wound, but may be getting the patient mobile again, reducing the unpleasant symptoms such as pain or odour, or explaining the delayed healing in an immunocompromised patient.
Treatment
The principle behind wound treatment is to change the wound bed environment from a chronic to an acute wound, and so aid in healing. Falanga suggested several clinical targets12 for wound bed preparation to achieve the acutely healing wound bed state.
Removal of necrotic or fibrinous tissue to promote formation of granulation tissue
Simple cleansing and irrigation with sterile water or saline will remove the debris from the wound surface, remove excess exudates, and decrease bacterial burden by removing heavily contaminated slough.3
Removal of deeply imbedded debris, necrotic and fibrinous tissue and bacteria requires debridement. Debridement is removal of devitalised or decontaminated tissue, and immediately returns the wound bed environment from a chronic to an acute state. Chronic wounds will require ongoing debridement, as build up of non-viable tissue needs to be removed to promote formation of granulation tissue. Although debridement usually occurs naturally, artificial debridement accelerates healing.13 For types of debridement and their indications (see Table 3).
Some clinicians believe that a moist wound environment will hinder healing and promote infection, but studies show that moist wound environments can actually accelerate healing by as much as 50%.17 However wound fluid, especially that from chronic wounds, does have a negative effect on wound healing13 and should be controlled.
Dressings (see Table 4) can successfully control exudates as well as reduce and prevent infection, stimulate autolytic debridement, reduce wound pain, and stimulate the development of granulation tissue. Excessive exudate is often caused by infection and should be investigated and treated where possible.
Achieve a well vascularised wound bed
Clinicians should make every attempt to ensure that the wound is well vascularised. This may involve removal of local pressures such as a callus on the feet. In some cases the intervention of the vascular team may be required for Doppler assessment and surgical revascularization.
Decrease bacterial burden
If an organism is identified, the patient should receive antibiotics, as discussed earlier. Clinicians should also consider an underlying metabolic factors predisposing to infection, for example poor glycaemic control. Debridement is also used to reduce bacterial burden, as it is fast and effective.
Control oedema - compression bandaging
Oedema is often seen in the lower limbs of people whose superficial and deep veins have incompetent valves. Techniques used to reduce oedema include raising the affected area where possible and giving diuretics. Compression bandaging (see tables 5 and 6) uses different types of bandages to produce graduated compression in the treatment of venous ulcers.16
VAC Therapy
Controlled negative pressure is applied to the wound to create a hypoxic environment which stimulates angiogenesis, and promotes the formation of granulation tissue. The risk of excessive bacterial colonization of the wound bed is reduced as VAC therapy gets rid of wound fluid, thereby reducing the bacterial burden.5 The wound is fully occluded using adhesive tape with intermittent or continuous suction applied at approx 120-125mmHg. The pump is adjustable and can be programmed to the appropriate amount of negative therapy that needs to be applied. Machines are large and treatment is expensive, so use is not widespread.
Future Concepts
Growth factors and cytokines
Much research has focussed on the use of topical growth factors and cytokines, which control key cellular activities including cellular division and tissue repair. The early optimism for cytokine and growth factor directed therapy was followed by mixed clinical results.23 How to deliver the factors and how to avoid their inactivation by the hostile environment of the wound bed are current problems.
Skin substitutes
Cultured grafts of allogenic and autologous epidermal kertinocytes are thought to help chronic wounds which don't respond to conventional treatment.24
Gene transfer technology
By inserting genes into cells involved in the healing process, it may be possible to deliver specific therapeutic proteins into the wound site.25
| Table A Schultz's definitions of bacterial involvement in the woundw2 |
| Term |
Definition |
Wound contamination |
Presence of non-replicating micro-organisms in the wound |
| Wound colonisation |
Presence of replicating micro-organisms adhering to the wound that do not cause injury to the host |
| Critical colonisation |
Presence of replicating micro-organisms leading to increased bacterial burden causing a delay in wound healing |
| Wound infection |
Presence of replicating micro-organisms in the wound causing injury to the host. |
| Table B Types of wound investigation |
| Investigation |
Description |
Punch biopsy |
Cylindrical portion of tissue removed via a needle and sent for histological examination |
| Incision biopsy |
Transverse section of healthy skin and wound bed are taken for histological comparison |
| Doppler assessment |
If peripheral pulses cannot be felt, Doppler ultrasound imaging can be used to assess arterial circulation in that area |
| Bacterial swab |
Swabs of the wound bed are taken to detect and identify pathogens |
| Urinalysis |
Checking for glycosuria and a full blood count to detect anaemia and blood dyscrasias |
| Table 3. Types of Debridement and their indications |
| Type of Debridement |
Description |
Indication |
Advantages |
Disadvantages |
Autolytic |
Automatic process involving macrophages & endogenous proteolytic enzymes that liquefy & spontaneously separates necrotic tissue |
Occurs naturally in most people |
-Causes least amount of pain
Most cost effective
- free |
-Slow
-There is a high risk of infection |
| Surgical |
Removal of necrotic & non-viable tissue using a sterile scalpel |
-Large wound area
-Widespread infection |
-Fast
-Most effective
-Immediately converts chronic wound bed environment into an acute one |
-Painful
-Expensive
-Can cause bleeding
-Risk of damage to tendons |
| Enzymatic autolytic |
Application of topical exogenous enzymes to wound surface where they act in unison with endogenous enzymes. |
Removal of eschar from large wounds where surgical techniques are not appropriate |
- Can be applied to very large areas
- Useful for difficult areas such as those overlying tendons on the ankle |
-Produces excessive amounts of exudates
-Local irritation to surrounding skin |
| Mechanical |
Simplest form is use of wet to dry dressings but irrigation & whirlpool techniques are also used to physically remove debris for the wound |
Necrotic wounds at the inflammatory phase |
Reduces bacterial burden |
-Expensive
-Nurse time intensive cannot be used on granulation tissue
-Bleeding and pain on removal |
| Larval |
Sterile larvae of Lucidia Sericata fly are placed in the wound they produce powerful enzymes that break down dead tissue without harming healthy host tissue14 |
Large areas of necrotic tissue |
-Enzymes combat clinical infection15 |
Larvae can die in excess exudates |
| Table 4. The Role of Dressings on Different Wound Types. |
| Wound appearance/Characteristic |
Description |
Management aim |
Dressing choice |
Dressing description |
Necrotic |
Dead, devitalized tissue.
This tissue can become dehydrated in a hospital ward or centrally heated room, as it drys out it shrinks and darkens until it becomes olive green or black and hard & dry to touch. This hard necrotic tissue inhibits autolysis20 |
Keep the necrotic tissue moist therefore assisting autolysis |
1ary: Apply wet soaks via gauze
Or
cotton wool
Or
Intrasite gel 2ary: Melolin
Or
Opsite flexigrid |
Saline or water soaked gauze or cotton wool
Hydrogel Dressing inert to normal biological processes. Permeable to metabolites. Provide high concentration of water 70-90% contained in insoluble polymers.
Perforated plastic film dressing. Provides barrier to prevent evaporation of moisture.
Moisture Vapour Permeable Adhesive Film Dressing
|
| Sloughy |
Mixture of dead white cells, dead bacteria, rehydrated necrotic tissue and fibrinous tissue
A thick layer can build up quickly and it has been shown that slough can predispose to infection21 |
Control exudates and remove slough fluid from wound |
1ary: either as a dressing Iodosorb
Or
a paste Iodoflex applied to gauze
2ary: Melolin
Opsite flexigrid |
Dressing contains polysaccharide beads that absorb moisture and progressively move bacteria and cellular debris away form the surface of the wound. Also contains iodine that confers antibacterial properties |
| Granulating |
Complex combination of newly formed vascular tissues and fibroblasts |
Protect angiogenesis and promote wound healing |
1ary: Iodosorb Large cavities: Allevyn cavity wound dressing
Heavily exudative: Algisite*M
Or
Allevyn adhesive |
Highly absorbent dressing containing foam chips in a soft flexible pouch. The surface contains perforations to allow entry of exudates.
Calcium-alginate fibre dressing derived from algenic acid extracted from seaweed, creates a hydrophilic gel in the presence of exudates. Also contains high concentrations of calcium ions which are used by clotting factors in the clotting cascade, thus stabilising bleeding21
Hydrocellualr dressing- self-adhesive dressing that holds liquid within its microscopic structure |
| Epitheliasing |
Wound bed that has completed proliferation and is level with the surface, where epithelial tissue will begin to migrate over the wound surface |
Protect fragile tissue |
Algisite*M Replicare |
Layer of hydrocolloid (liquid absorbing particles in an elastic, self-adhesive mass), covered on the upper side by a semi-permeable polyurethane film22. Slightly absorbent major class of wound healing dressings. Dressings are occlusive providing an anaerobic environment that promotes angiogenesis. |
| Malodorous |
Unpleasant smell associated with wound exudates or poor hygiene21 |
Reduce unpleasant odour |
1ary: Carboflex
2ary: Allevyn adhesive
|
Dressing contains activated charcoal that has the ability to absorb odour. May also contain silver ions that destroy bacteria21. |
| Table 5. Types of Bandage. |
| Class 1 |
Class 2 |
Class 3 |
Class 3a |
Class 3b |
Class 3c |
Class 3d |
Conforming stretch |
Light support |
Compression |
light (1417mmHg) |
Moderate (18-24mmHg) |
high (25-35mmHg) |
extra (36-60mmHg) |
| Table 6. Types of Compression. |
| One layer |
A short stretch class 2 bandage with or without a primary dressing over the wound. |
| Two layer |
A layer of absorbent protective bandage plus a spirally applied class 3c bandage. |
| Three layer |
A layer of absorbent protective bandage plus a spirally applied class 3c bandage, plus a retaining bandage. |
| Four layer |
Absorbant protective bandage, plus a conforming bandage, plus a class 3a bandage in a figure of eight, plus a spirally applied bandage |
Aroushka L James third year medical student
Email: Aroushka.james@stud.man.ac.uk
Ardeshir Bayat honorary lecturer and specalist registrar in plastic and reconstructive surgery University of Manchester
Email: Ardeshir.bayat@man.ac.uk
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