22 Reconstructive burn surgery
Improvements in burn survival have shifted the focus of burn care and research towards long-term outcomes. Accordingly, reconstructive burn surgery has become an increasingly relevant topic in the care of the burn patient.
The majority of secondary burn defects are due to scarring and contracture. To correct deformities, scar release is necessary and then appropriate coverage is obtained from skin grafts or flaps – either local or distant.
Advances in critical care and surgical management have significantly improved survival following burn injury. In fact, survival following even severe burn injury has become the rule rather than the exception. Accordingly, there is increasing emphasis being placed on long-term outcomes following burn injury and reconstructive surgery for burn survivors has become an increasingly relevant topic in burn care.1 Burn reconstruction refers to the numerous and varied procedures performed on healed wounds or skin grafts. The overall goal of burn reconstruction is to improve both the appearance and function of the person who sustained a burn injury. These procedures should never be considered “cosmetic” – they are reconstructive as they seek to restore that which has been lost to injury.
Burn reconstructive surgery, as much as anything else in plastic surgery, requires a principled approach. The surgeon must accurately diagnose the problem including which types of tissue are deficient; identify which tissue is available for reconstruction, and then formulate a rational plan based on these findings. Limited availability of healthy tissue poses one of the greatest challenges in burn reconstructive surgery, as many burn patients, particularly those with extensive burn injuries, will have limited donor site availability for skin, subcutaneous tissue and, on occasion, muscle.
The need to address the complex problems resulting from burn injury is as old as the history of plastic surgery itself. The field of burn reconstruction has no particular historical beginning but has evolved as modern care of the burn patient has evolved. Over the past three decades, as early surgical management of acute burns has become the standard of care, there has been increasing attention paid to the potential role of surgical management of the late effects of burn injury.
The timing of reconstructive procedures vary; they could occur relatively early in the post-injury period (i.e., weeks), years or even decades, following injury. By and large, surgery on burn scars should typically occur once the scar has matured. The scar maturation process can take up to 1 year or longer. Allowing scars to fully mature could reduce or, in some cases, eliminate the need for burn reconstructive procedures altogether. As a general rule, the body should be given every chance to try and improve on its own without surgery. There are certain exceptions to waiting for scar maturation to occur including severe debilitating early contractures, severe eyelid contractures, unstable wounds and exposed vital structures.
There are several critical prerequisites that need to be met prior to embarking on any reconstructive endeavor. First and foremost, the patient must want the procedure performed and be psychologically prepared for the procedure. Unlike acute surgeries which may be life-saving, reconstructive procedures are usually elective and many patients may not be readily prepared to undergo more surgeries and to comply with postoperative splinting, garment wearing and the rigorous exercise regimens needed to achieve optimal results. In addition, many patients may not be psychologically ready to come back into the hospital for an inpatient stay. Children must also be included in the surgery decision-making process. Favorable outcome will require children to cooperate with postoperative plans and, therefore, in the cases of school-age children and adolescents, we make an effort to ensure that the patients themselves want a procedure and it is not just the desire of the parents. The cooperation of the child in terms of wearing splints, garments and performing physical therapy is critical to the success of reconstructive procedures and if the child does not want to have surgery performed, there is a high risk of poor postoperative compliance.
It is also critical that patients have realistic expectations regarding what can be achieved with reconstructive surgery. Many patients come to the burn clinic wanting their scars removed as soon as possible and many may have the unrealistic expectation that defects can be easily and rapidly fixed – that scars can simply be “erased”. Expectation-reality matching must be achieved and the concept that scars cannot simply be erased must be clearly articulated. It is also crucial to explain to patients that several procedures are often needed in order to address all reconstructive needs. When possible, procedures should be grouped, yet this needs to be done cautiously. For example, a procedure that requires early mobilization of a joint, such as a capsulotomy or capsulectomy, should not be performed at the same time as a procedure that might require immobilization of an adjacent joint. Similarly, performing procedures on either both upper or lower limbs simultaneously should be avoided, so the patient will still be able to provide self-care following surgery. Unfortunately, there are deformities for which there may be no good reconstructive options or that the risks involved in a procedure may exceed the potential benefit. This too must be explained clearly to the patient but an effort should also be made to provide some hope that new techniques or technologies may one day provide a solution.
Hypertrophic scarring remains the most significant source of pain, discomfort, and misery for burn survivors and constitutes the chief complaint of the majority of patients seeking burn reconstruction (Fig. 22.1). Despite the frequent occurrence of these scars – estimated to be as high as over 50% – still little is known about the causative factors and, therefore, a cure or effective prevention strategy remains elusive. Risk factors for hypertrophic scarring include delay in wound closure, infection and race (i.e., patients with pigmented skin are believed to be at higher risk of forming hypertrophic scar).2 There have been several proposed prevention and treatment strategies for hypertrophic scars, including steroids, oral anti-inflammatory agents, pressure garments and silicon, and all have been reported to have varying levels of effectiveness. Steroid injection into scars and topical silicon sheeting can be used during the period of scar maturation to alleviate symptoms of pain and itch and potentially improve scar appearance. However, scar injection may be difficult to perform in children and is seldom useful for broad areas of hypertrophic scar.
Wound contraction is a natural process that occurs in all healing tissues and in all skin grafts. The amount of contraction may vary based on thickness of tissue (i.e., full thickness skin grafts contract less than split thickness grafts due to the presence of more dermis). Contractures result when contraction occurs over a mobile joint and leads to functional compromise; they are negative sequelae of the natural process of contraction and often require surgical correction. Contractures can involve the skin as well as underlying tissues such as muscle and tendons. Limited contractures may be overcome with aggressive range of motion and splint immobilization. However, more significant contractures will require release and subsequent grafting or flap coverage. Even after contracture releases, patients must be aware that prolonged periods of intense range of motion exercises is required as is the use of splints in order to prevent the recurrence of contractures.
Contracture release is usually achieved by incising the scar band at its point of maximal tension. Given that contracture bands typically exist in a sea of surrounding scar, full release requires incision beyond the scar band itself. In addition, in the axilla and eyelids, we typically include a superior and inferior dart at either end of the scar incision line in order disrupt the scar pull. The incision should be carried down through the scar to healthy appearing tissue. In some cases, release of the subcutaneous tissue and muscle fascia may also be required to achieve full release. This is often the case in the neck and axilla. Long-standing deformities of the digits may also require tenolysis or, in some cases, tendon lengthening or transection, as well as joint capsule release. The surgeon must be aware of the potential need to divide these underlying structures and challenges in covering the subsequent defect, since skin grafting is not possible on exposed tendon, bone and joint.
In some cases, total scar excision is necessary and practical. This is particularly true for smaller or discrete areas of scar. There are two general approaches to scar excision: intralesional and extralesional. When performing intralesional excision, a rim of scar is left in the wound and subsequently closed. The purported benefit of intralesional excision is that there will be no new tissue injury – the incision is made through previously scarred tissue only and therefore the process of scar formation has already occurred in this tissue and is unlikely to recur (Fig. 22.2). This is in contradistinction to extralesional excision, in which the incision is made in the healthy tissue surrounding the scar so the entire scar can be removed. The relative risks and benefits of each approach should be discussed with the patient prior to surgery. Many scars are too large to be removed in one setting and often require several “serial” excisions. We typically wait 8–12 months between serial excisions in order that the tissue can sufficiently heal and soften so that it can be optimally mobilized again to achieve closure.
Plastic surgeons often utilize the reconstructive ladder as a way to approach reconstructive procedures. The ladder represents a list of procedures from simple to more complex for surgical management and forms an appropriate framework for approaching burn reconstructive procedures. Below is a discussion of the most common approaches to wound closure.
Skin grafts remain the workhorse coverage for burn deformities – particularly because the defect in most cases resulted from the loss of skin. Ideally, thicker grafts are utilized following contracture release because the more dermis present in a graft the less contraction that occurs during the healing process. Full thickness grafts are generally reserved for small areas on the hand and face, so the full thickness skin graft donor site can be closed primarily. The use of tissue expansion of unburned areas of skin to generate larger full thickness skin grafts is also possible for larger areas such as the face and neck. It is important to take full inventory of available donor sites in the outpatient clinic prior to operation, so one is aware what tissues are available and the patient is aware of from where the skin graft will be harvested. I will often ask the patient’s input on donor site selection if there are multiple options. It is also necessary to ration donor sites appropriately based on the need for other potential procedures. For example, we will reserve the scalp if we anticipate needing to graft large areas on the face.
Skin substitutes – particularly dermal substitutes – have been used in the management of both acute burn wounds and burn reconstruction. The use of dermal substitutes is particularly useful when there are limited donor sites available. Given the general preference to use thicker skin grafts with more dermis to minimize contraction and recurrent contracture, dermal substitutes offer the potential advantage of augmenting native graft dermis. However, there are drawbacks to the use of skin substitutes including infection risk and usually the need for more than one surgical procedure – one for application of the material and the second for skin grafting following a period of time to allow for adequate vascularization.
There exists a veritable alphabet soup of local tissue rearrangement flap options that have been described, including Z-plasty, Y-V-plasty, V-Y-plasty and W-plasty. Each has its distinctive geometric properties, as well as relative benefits. We most commonly use Z-plasties (Fig. 22.3) and Y-V-plasties to address scar bands (Fig. 22.4). It is critical to understand that these procedures are most appropriate for scar lengthening and are not the solution to all reconstructive problems. Areas with even moderate degrees of missing tissue will be inadequately addressed by a Z-plasty and require the addition of soft tissue either in the form of a skin graft or a flap. The principal drawback to Z-plasty use is that transposition and advancement of the Z-limbs requires extensive undermining and this often means undermining scar that can result in partial flap ischemia. For this reason, in many cases we prefer to use Y-V plasties because they require minimal flap undermining in order to achieve the desired advancement.
Axial flaps, fascial flaps and muscle flaps (both pedicled and free) can be used for wound closure. Fascial flaps such as the radial forearm flap are very useful for providing thin pliable coverage following contracture release or for lining of facial structures such as the nose. Muscle flaps are particularly useful for areas with significant contour deformity that require bulky soft tissue. Muscle flaps are also useful for breast reconstruction (as described below) and to cover chronically exposed joints.