Scarring is often perceived by the media and the general public to be horribly disfiguring and disabling. However, over the past few decades, advances in burn care have not only led to greater survival among those who sustain large burns, but in the majority of cases, to excellent functional and aesthetic outcomes.
Unfortunately, in some instances, poor outcomes are inevitable. These include for examples injuries caused by high-voltage-driven electrical current conduction, or house fires.
In the former, injuries may result in major limb amputations, which markedly diminish outcomes. In the latter, a large proportion of the total body surface area (TBSA) is affected, especially when clothing catches on fire.
Scarring, a natural response to injury
The scarring process is part of the wound healing response, which always starts with inflammation, followed by proliferation, and remodelling. It is important to keep in mind that scars can take up to 24 months to mature.
Scar modulation can be effective and should persist in some form throughout this period. In addition to optimal surgical management, effective scar modulation measures, which include reducing tension across the scar, the provision of taping, hydration, and ultraviolet protection of early scar tissue, can improve outcomes.
Depth, size, and area matter
Functional and aesthetic outcomes depend on the depth, size, and the area where the burn occurs. These three aspects will determine the timing and approach to management.
The majority of burn injuries are superficial enough and heal spontaneously, quickly and with excellent outcomes. Superficial burns are classified as:
- Superficial partial thickness
Similar treatment priorities are recommended:
- Preventing infection (which can deepen the injury)
- Controlling pain (which facilitates dressing changes, compliance with therapy and mobilisation and hastens discharge).
Deep dermal or full thickness burns
These injuries are deep, resulting in prolonged healing (granulation tissue formation and wound contraction). While partial thickness burns can heal spontaneously with minimal scarring, deep partial thickness and full thickness burns require more than three weeks to close and are often associated with significant scarring and functional limitations, unless excised and grafted within the first few days.
These burns are more complex to treat because of recurrent wound infection and have a negatively impact on patients’ functionality. Scars are referred to as hypertrophic and dysaesthaetic (abnormal sensation), often causing itching and pain.
The treatment priorities in these burns are to:
- Halt secondary intention healing (associated with considerable tissue loss and wound edges are very far apart. The wound is left open to heal by granulation, contraction, and epithelialisation. Can result in delayed wound closure)
- Replace with primary intention healing (wound edges are in close proximity, haemostasis is followed by inflammation and cellular wound debridement, and the dermal fibroblasts rapidly produce collagen to bridge the ‘narrow’ gap and restore resistance of the skin to external forces).
The second most important step to consider is the size or surface area of the burn injury. This is estimated as a percentage of the %TBSA.
A small area of full-thickness burn (localised to the affected area) can be treated with early excision and immediate skin grafting. Donor site for the skin graft should be taken from a non-cosmetic area. Early scar therapy can begin once the graft has taken and is robust.
As the size increases, treatment challenges increase accordingly. Three burn-area percentages are considered important:
- 20% TBSA: Intravenous fluid resuscitation is routinely initiated, and the effect of the burn inflammatory response ceases to be localised to the burn area and has systemic consequences. The resultant fluid shifts and loss from the circulation are thus markedly more significant and, if untreated, result in burn shock with cardiac and renal consequences.
- 50% TBSA: The burn area usually exceeds the available donor site area (since we do not harvest grafts from the unburned face, neck, palms of hands or soles of feet). Strategies for wound closure are important. At burn sizes just in excess of 50% TBSA, this might merely involve skin graft meshing at a higher ratio (eg 1:3, rather than 1:1.5). At greater burn sizes, serial grafting may be necessary and should be planned to heal pivotal areas first (hands, face, neck, major joints). To facilitate skin closure for burns above 50% TBSA, almost all of the unburned skin must be harvested, often repeatedly.
- ≥80% TBSA (full-thickness burns): These injuries often prove fatal. Little or no unburned areas are available for wound repair. Injuries are often accompanied by smoke inhalation and other co-injuries. Such injuries are classified as ‘unsurvivable’ in the majority of burn units. These patients should receive palliative and comfort care prior to death. For patients who do survive these devastating injuries, long-term scarring issues are daunting, and return to useful functioning is extremely challenging.
More than 50% of burn injuries involve the head and neck areas. Deep second and third-degree burns in this region often result in hypertrophic scar formation. These injuries require immediate or early reconstruction.
If reconstruction requires grafting, the best functional and cosmetic outcomes are generated by thicker, unmeshed (sheet) split skin grafts. In the patient with significant burns, this requires a large proportion of the available donor sites to cover relatively small surface area/s. Bigger areas are left un-grafted.
Reconstruction of the eyelids and lips is challenging. Small full-thickness grafts or flaps are often used. It is crucial during to identify areas capable of healing spontaneously, bearing in mind that the deeper adnexal structures in facial skin often allow even burns, which appear deep, to heal without intervention. The best course of action is often to allow the face to heal spontaneously as much as possible and then plan appropriate reconstruction for scarred areas.
The neck is prioritised for early grafting not only for function but also to allow for tracheostomy placement as severely burned patients may require prolonged intensive care and ventilation.
Full-thickness burns on the dorsal aspect of the hands are grafted to allow early mobilisation and return to function. Early intervention by occupational and physiotherapists will improve outcome.
The glabrous skin on the palm and areas of partial thickness burn are routinely allowed a ‘trial of life’ to allow preservation of this highly specialised skin.
When a graft is placed over a joint, in particular the elbow and knee, contracture reduce the range of movement. This contracture is less significant than if the burn had been left to heal by secondary intention.
Subsequent scar management requires intensive occupational therapy and physiotherapy to regain and maintain range of motion. Contractures are more likely to occur in the more severe burns, those caused by flame and those in children and females and burns affecting the neck skin (due to the presence of the platysma) and the upper limb.
Silicone sheeting, or gel, is universally considered the gold standard in prophylactic treatment for hypertrophic or keloid scars. The efficacy and safety of this approach have been demonstrated in numerous studies.
Hypertrophy is managed by aggressive scar modulation, which include the use of pressure garments, silicone therapy and moisturising and massage.
Moisturising and massage are often described as ‘softening’ scars, most likely due to the reorientation of collagen fibres. An ideal moisturiser should be one that is conducive to scar maturation, is non- or minimally irritant, prevents skin drying, minimises trans-epidermal water loss and has no negative effect on barrier function.
The symptomatic manifestations of suboptimal scarring are difficult to manage, particularly pain and itch. Itch is challenging as the symptoms are subjective and the treatment is multimodal with no ‘magic bullet’ to prevent or ameliorate it.
Pain control and analgesia is vitally important – particularly during dressing changes. Pain control should be managed by experts. Pain control is also essential for effective rehabilitation.
Take home messages
- Accurate burn depth, size and surface area assessment play a crucial role in the timing and approach to management
- Immediate/early burn eschar excision and rapid wound closure with either immediate skin grafting or staged with temporising skin substitutes plus skin grafting and/or cultured skin, should be considered
- Treatment of burn injuries to the face, neck, hands and joints is a priority
- Immediate scar management and mobilisation utilising therapists lead to improved outcomes
- Later scar management such as resurfacing and excision is viable.
- Damkat-Thomas L and Greenwood JE. Scarring after burn injury. Intech Open, 2019.
- Kwon SH, Barrera JA, Noishiki C et al. Current and Emerging Topical Scar Mitigation Therapies for Craniofacial Burn Wound Healing. Front Physiol, 2020.
- Marshall CD, Hu MS, Leavitt T et al. Cutaneious scarring: Basic Science, Current Treatments and Future Directions. Adv Wound Care, 2018.
- Singer AJ and Boyce ST. Burn wound healing and tissue engineering. J Burn Care Res, 2018.