Split-Thickness Skin Graft for Scar Release, Permanent Pigment Transfer, and Fractional CO2 Laser Therapy

Abstract

Pediatric burns are one of the most common forms of injury affecting children worldwide. Of these, hand involvement occurs in 80–90% of such incidents. With the skin in children already diffusely thinner throughout the body than adults, this provides a particular challenge for areas naturally possessing thinner skin, such as the dorsal hand. There, the cutaneous tissue is the only protection for vital structures in the hand that allow full function, such as extensor tendons, nerves, and vessels. Injury to this area early in life can have a detrimental impact on how the survivor interacts with the physical world, affecting their functional capacity and quality of life. Today we present a case of burn contractures on the right hand of an 8-year-old boy that will be released using a split-thickness graft, along with a pigment transfer graft for his left knee and fractional CO₂ laser therapy over areas of hypertrophic scar tissue on his bilateral upper extremities. The split-thickness graft will greatly decrease the tension built up from the burn contracture, while the fractional CO₂ laser procedure can soften the surrounding scar, allowing mild remodeling and increased range of motion.

Keywords

Plastic surgery; reconstructive procedures; scar remodeling; hand surgery; laser therapy.

Case Overview

Background

Burns are among the most devastating injuries and are the fourth most common trauma, with 25% occurring in children under the age of 15.^1,2 Children are more vulnerable to burn injuries for various reasons. A major factor at play involves the discrepancy between body surface area. They have three times the body surface area to mass ratio than adults.³ Complications of this leftward shift include an increased volume and rate of fluid loss and a higher potential for hypothermia. Skin thickness also contributes. Children’s skin thickness is approximately 70% that of adults, with the dermal layer thickening throughout the aging process from infancy to puberty.³ This demographic, therefore, experiences a greater depth of burn injury than an adult would have experienced at similar temperatures. These intrinsic traits culminate in children having  a greater likelihood of presenting with more severe burns than their adult counterparts, making timely management of both acute and chronic injuries vital to recovery. After the acute management of burn victims, involving correction of electrolyte imbalances, volume depletion, and airway care, the focus shifts to the functionality of the affected area. Treatment goals revolve around minimizing burn contracture, secondary changes in the surrounding tissue, and preserving neurovascular structures.⁴ Special considerations need to be taken into account when burns affect the hands, which occurs in 80–90% of incidents.⁵ This large occurrence of hand burns is proportional to the rate of hand deformities. Because hand function is a vital aspect of our ability to interact with the world, full utility after recovery is linked to the patient’s quality of life. Deformities arise depending on multiple factors, one being the type of wound healing process occurring at the site. Burns can heal either by regeneration of skin or repair.⁶

Regeneration occurs if the burn is superficial or even partial-thickness, sparing the levels containing specialized epithelial cells. If they survive, keratinocytes can migrate from the skin dermal appendages to proliferate and differentiate, healing the defect.⁷ For deeper insults, healing begins around the edges of the wound, with connective tissue layer deposited to replace lost tissue.⁷ Contractures occur as part of the normal healing process via stimulation of myofibroblasts to decrease the size of the wound. This reduces the amount of epithelization and collagen deposition needed to fill the defect and is adequate for small areas with loose skin.⁶ Problems arise when large insults need to be healed in areas of already tight or thin skin. These mechanisms then impair the elasticity of the skin and increase tension, leading to functional loss.

Management, therefore, is complex and tailored to the depth of the burn injury: superficial, deep partial-thickness, and full-thickness. Initial post-burn treatment decisions should be made based on providing the maximum, perceivable benefit for the patient.⁸ From there, aesthetic deformities, secondary changes in musculotendon units, and timing of correction must be carefully considered.⁸ Over time, contractures or edema-induced tension can cause joint stiffening and tendon shortening. If neglected, hand deformities can permanently prevent full function. One of the major treatment options for both acute and chronic treatment of burns is skin grafting: the transfer of cutaneous tissue from one area of the body to the exposed wound.⁹ Skin grafting in general is an essential technique in plastic surgery and dermatology. It’s utilized in a broad spectrum of clinical situations, including traumatic injuries, defects following cancer removal, burn repair, release of scar contractures, congenital skin deficiencies, hair replacement, and vitiligo treatment.¹⁴

Grafting is generally used to cover larger wounds with skin from an area that will easily heal. Early coverage of exposed wounds provides environmental protection, temperature regulation, and decreased water loss. Skin grafts are different from flap techniques in that they do not have their own blood supply. Therefore, the wound bed on which they are placed must be clean and well-vascularized for successful take. The two major types of grafts, split-thickness and full-thickness, are chosen based on the location and size of the burn. Skin grafting, along with the use of laser technology to introduce micropores in less-hypertrophic scar sites were the chosen methods of management for our case.

Focused History of patient

Here we present an 8-year-old child from Honduras who, at the age of 2, incurred a deep scald burn to his right hand, along with small areas of scarring in his right knee and left hand as well. The patient’s chief complaint is increasing tension in the scar tissue in his right hand. The dorsum of the hand contains a burn contracture that is causing deformity of his fingers and inhibiting range of motion. The patient is also concerned about an area of hypopigmentation on his knee.

Indications

The use of grafting techniques needs to be considered on a case by case basis. In general, grafting is indicated if simpler methods of closure will not provide adequate healing, the patient has available donor sites, and the recipient site is clean and well-vascularized.⁹ Specifically, split-thickness grafts can be used in both acute and chronic skin loss for coverage of deep partial-thickness defects, full-thickness defects, and exposed muscle.⁹ Larger areas are able to be covered with split-thickness grafts as opposed to full-thickness due to the small portion of dermis taken with it and the donor site’s ability to heal by re-epithelialization.

Contraindications

Absolute contraindications include active infections and bleeding at the wound site or exposed structures without an adequate vascular layer.⁹ Relative contraindications to consider are recipient sites over joints or anatomic landmarks that could potentially limit mobility and aesthetics.⁹ Tobacco, chronic steroid use, and hematological dysfunctions are risk factors for graft failure and should be taken into account in the treatment plan.

Procedure

Prior to surgery, the hand was marked; one in a horizontal line through the main contracture on the mid-dorsal aspect to the webspace between the first and second digits, and multiple small z-plasty tracings in the thumb webspace and ulnar edge. The first cut was made superficially through the scar tissue in the largest of the premarked lines. Next, a similar cut was made through the web space, releasing the scar into the normal tissue on the palmar and ulnar sides of the hand. Undermining completed along all incision lines provided slightly larger skin edges for eventual graft connection. The width of the recipient site was measured in preparation for harvesting the right-sized graft. During graft harvesting, an epinephrine-soaked sponge was placed on the opened wound to decrease bleeding.

The size necessary for the graft was marked on the right lateral leg. Diluted saline with epinephrine was injected into the donor site, which was then cleaned with Betadine and slickened with mineral oil. An electric dermatome, calibrated to 14-µm thickness and held at a 30–45-degree angle, was used to harvest the graft. Before laying the graft in the recipient site, any bleeders were cauterized. Simple sutures placed initially in the opposite corners held the new graft stable as the rest of the stitches were sewn along the edges in the direction of the skin graft to the hand side. Placement of drain holes decreased potential accumulation of bleeding underneath. After irrigation, a tie-over bolster dressing of Xeroform and cotton was placed on top of the graft, creating the compression and immobilization necessary for graft success while also reducing the potential of hypertrophic scarring.

The second procedure used a dermabrator set at a decreased thickness to obtain a smaller, thinner graft for covering of the patient’s hypopigmented area. After injection of epinephrine, the graft was placed and immobilized with Dermabond. The donor site was then covered with Xeroform followed by Telfa and  wrapped in dry gauze. An anesthetic combination of 0.25 Marcaine and adrenaline anesthetized the site through injection near the lateral femoral cutaneous nerve and smaller nerve branches in the immediate area. Kerlix dressing was wrapped around the graft site. The leftover anesthetic mixture was then used for a dorsal wrist block.

The final procedure involved fractional laser treatment at 25 mJ and 10% density to the patient’s hypertrophic forearm and left hand scarring. Kenalog and betamethasone were rubbed into the micropores created from the treatment, after which the wound was dressed with a Vaseline gauze.

Complications

Complications can be categorized as short-term or long-term. In the short term, any movement between the graft and skin bed increases the likelihood of graft failure. Therefore, fluid accumulation from infection, hematoma, seroma, or shearing injuries to the area can lead to incomplete take.⁹ Issues such as wound contractures or pigment inconsistency fall underneath long-term complications.

Discussion

The patient in our case presented with significant scar contracture following a burn injury sustained at the age of two. As he grew, tension within the skin continued to increase to the point where his hand functionality became impaired, almost seeming like a tendon abnormality. The first procedure’s focus was to release this built up tension via skin incision through the scar tissue, creating an extensive area of exposure. Given the dimensions of the release, a skin graft was indicated to cover the area. This would increase laxity over the dorsal hand, freeing movement of the appendage. A split-thickness graft, which refers to a  graft containing the epidermis and a small portion of the dermis, was chosen for treatment.⁹ Retention of dermis portions within the graft is vital for successful take because it includes the dermal appendages from which epithelialization can occur. This prevents a large percentage of contractions within the donor graft, excluding the small amount taken into account at the edges. The earlier skin grafts are used post-burn, the more successful they are at controlling the unwanted sequela of wound contraction. Our patient received a skin graft at the time of his burn, helping to hold off shortening of neurovascular and musculotendinous units and joint or bone deformities.

Split-thickness grafts can be harvested via several different methods, including the one used here, an electric-powered dermatome. The benefits of choosing this method come from its ability to harvest the graft at a uniform depth, providing consistency. Also, graft thickness is able to be adjusted, making the electric-powered dermatome ideal in cases like ours, where multiple recipient sites require varying thickness in their grafts. Once harvested and placed on the recipient bed, the graft is secured into place postoperatively for 5–7 days to allow the graft take to progress through three phases: imbibition, inosculation, and revascularization.⁹ The first involves the graft obtaining oxygen and nutrients via passive absorption from the well-vascularized wound bed.¹⁰ During inosculation, a vascular network proliferates between the two surfaces, causing the graft to now have its own supply and pink up.¹¹ Finally during the revascularization phase, new vessel growth occurs into the graft from the wound bed. Once this process is complete, the graft continues to mature into the recipient bed, lasting up to several years. Changes in the maturing skin graft can include pigmentation, flattening, and softening.⁹  

Thinner split-thickness grafts can be used to correct areas of depigmentation. When a burn is deep, it can affect the pigment in the skin for a time period of around six months to a year. However, if pigmentation does not normalize, the burn could be deeper than expected, and interventions for correction can be planned. Hypopigmentation defects require a much thinner graft since only the epidermis is required, containing the basal cell layer composed of the melanocytes that produce skin pigment. The presented case used the same donor site as the hand due to the availability of undamaged skin and to keep the eventual wound-healing process confined to one location. Attachment of the graft was completed with Dermabond since the thinness of it made sewing it into place a more difficult option. 

In cases where scarring has undergone mild hypertrophy, laser treatments can be performed. One such treatment is a fractional CO₂ laser that treats skin in a pixelated pattern, allowing the intervening skin to remain intact.¹² This is better tolerated than previous laser technology that treated the whole skin and was associated with long-term effects of hypo/hyperpigmentation and permanent scarring.¹² Since fractional CO₂ does not treat the entire surface, it negates or decreases the severity of these adverse effects. Its use has been growing in a variety of treatments, including atrophic acne scars and skin rejuvenation.¹² Studies have begun to show efficacy in treating burn scars, reporting improvement regarding pain, itching, and scar tightness.¹³ We have used it here on the patient’s mildly hypertrophic scars along his forearm and left hand to soften the skin. Topical agents, triamcinolone and betamethasone, were rubbed into the micropores created from the treatment, permitting deep penetration into the skin for the steroid to achieve its goal of breaking bonds between collagen fibers to reduce scar tissue.

Alternative Grafting Options

Two alternatives to the choice of split-thickness grafting are using a full-thickness graft or a split-thickness meshed graft. A full-thickness graft was passed over in this case on account of the size of graft necessary to close the released area. Full-thickness grafts, while preserving a greater allotment of normal skin characteristics and being more resistant to contraction, have higher chances of failure.⁶ Their use is best in small defects located in highly visible areas, usually the face. They also leave behind donor sites that are required to heal by primary closure after one use instead of the fast regrowth and reusability seen in split-thickness donor sites.

The addition of mesh to split-thickness grafts is indicated when the available donor site is smaller than the wound size. Meshing allows the skin graft to be expanded through placement of holes throughout the skin in varying ratios, increasing the surface area it can cover. These holes also prevent accumulation of fluid buildup between the layers, decreasing the chance of graft failure.⁹ In this case, the patient had readily available donor sites that provided a large enough skin graft without necessitating the use of meshing.

Postoperative Care

Graft stability usually takes three weeks to achieve.⁶ Within the postoperative period, the use of a combination of splints and daily physical therapy aids in preserving graft take and restoring full range of motion. Physical therapy should be continued until maturation of the graft is complete, as determined by the ability to move and pinch the graft over the recipient area.⁶

Outcomes and Follow-Up

In this case, the outcomes of treatment were assessed using the 3.0 observer generic scale of POSAS The Patient and Observer Scar Assessment Scale,¹⁵ both before the surgery and 6 months post-operation. This assessment has both an observer portion and patient component covering similar outcome measures in medical vs layman terms on a scale of 1–5 (one being akin to normal skin) correlating with the words “not, a little, moderately, very, and extremely”. These included vascularity, pigmentation, firmness, surface texture and level, tension, and adherence on the observer portion and parameters such as color, shininess, hard feel, sensitivity (pain, numbness, sensation, itch, burning paresthesias), tightness, pull, fragility, and dryness for the patient. A numerical score is then added up from all answers. For our case, the scores were as follows: the dorsal surface of the right wrist had a score of 32 before the surgery and 23 after; the right knee had a score of 22 before the surgery and 14 after; and the right arm and left hand had a score of 18 before the surgery and 12 after. Each total showed improvement from scores prior to the surgery, demonstrating both patient perceived and medically-assessed improvement.

Equipment

• Betamethasone
• Kenalog 10 mg/cc
• Mineral oil
• Kerlix
• Stapler
• Anesthetic (0.25 marcaine and adrenaline)
• Dermabond
• Heavy scissors
• Webster needle driver
• Cotton
• Xeroform
• Adson tissue forceps
• 4-0 silk sutures
• Electric dermatome
• Epinephrine-soaked sponge

Disclosures

There are no disclosures that need to be made at this time.

Statement of Consent

The parents of the patient referred to in this video have given their informed consent for surgery to be filmed and were aware that information and images will be published online.