Pediatric Burn Reconstruction

In this article, the author surveys the best available evidence to guide decision-making in pediatric burn reconstruction. Evidence-based protocols are examined in the context of optimizing form and function in children who have sustained burn injury.

Key points

  • Lacking high quality outcomes data to guide pediatric burn reconstruction, the best available data today is comprised largely of case series and expert opinion.

  • Laser is a powerful tool that can diminish the need for more morbid approaches in many patients.

  • Advances in microsurgery, and now supermicrosurgery, have made delicate, large, supple perforator flaps possible even for very small infants and children.

  • Key complications of burn scar contracture in the growing child include distortion of dentoskeletal balance, breast development, hand balance, and limb length discrepancy.

Introduction

How should our reconstructive algorithms be tailored for children with burn reconstructive needs? Does developmental stage influence the problem materially in comparison with adults? Ideally, pediatric reconstructive algorithms following burns would be informed by high-quality data, including patient-reported outcome measures. But as was demonstrated in a recent systematic review, very little exists at this point. But we are not entirely without guidance, and the following is a hearty effort to glean the best available evidence to support the decision-making process in pediatric reconstructive burn surgery.

Introduction

How should our reconstructive algorithms be tailored for children with burn reconstructive needs? Does developmental stage influence the problem materially in comparison with adults? Ideally, pediatric reconstructive algorithms following burns would be informed by high-quality data, including patient-reported outcome measures. But as was demonstrated in a recent systematic review, very little exists at this point. But we are not entirely without guidance, and the following is a hearty effort to glean the best available evidence to support the decision-making process in pediatric reconstructive burn surgery.

Presurgical considerations

In addition to the reconstructive problem at hand, planning should take into consideration the overall social, emotional, and neurocognitive development of the child. Apart from potential effects of surgery per se, interruptions in normal life due to medical care can have long-term consequences as well. Developmental pediatricians suggest that children between the ages of 6 months and 4 years are sophisticated enough to experience great stress from medical interventions but lack the developmental tools to understand and cope. Hence, this may not be the best time to undergo repeated painful interventions. The third grade has been highlighted by multiple investigators as a watershed period as well. Children who have not achieved literacy by this age are 4 times more likely to drop out of high school than proficient readers. Although this observation is certainly multifactorial, it underscores how early childhood influences long-term life outcomes.

The effect of general anesthesia on development has been a hot topic in recent years. Preclinical studies in a wide variety of neonatal animal models have demonstrated neurotoxicity from general anesthetics, including apoptosis and reduced synaptic sprouting, with long-term structural and behavioral impact. One Swedish population-based study found a mean decrement of 0.97% (95% confidence interval, 0.15%–1.78%) in the IQ of teenagers who had experienced a general anesthetic before 4 years of age. But the best data to come out so far report the results of a randomized controlled trial of isoflurane general anesthesia versus awake spinal anesthesia in neonates undergoing herniorrhaphy. Bayley Scales of Infant and Toddler Development showed no difference at 2 years and will be followed up with Wechsler IQ testing at 5 years of age. At this point, there does not seem to be strong evidence implicating a single early anesthetic as neurotoxic to human neonates. Hence, even the youngest child should be offered surgery if a strong indication exists. But as ever, the surgeon should strive to be efficient with surgical interventions in the developing child.

Growth and development

Characteristic proportions of the growing child are also distinctive, influencing reconstructive planning. In the first year of life, the head represents 19% of total body surface area (TBSA), whereas the extremities are relatively small. The thigh is only 5.5% of the TBSA at this point; hence, large wounds of the head can be demanding and the lower extremity offers relatively small surface area for donor tissue. By 7 years of age, body proportions begin to approach maturity. The pubertal growth spurt begins at around 10 years of age and lasts between 2 and 3 years. This period of high growth velocity can exceed the capacity for burn scars to grow. Bilmire observes that periods of rapid growth are attended by increased feelings of tightness but that these often spontaneously resolve within 6 months. Hence, he suggests that tightness alone is not a strict indication for surgical intervention.

But burn scar can restrict growth to an extent, in some cases resulting in limb-length discrepancy. One review of 159 patients found a deficit of 2 to 6 cm in expected height in children with burns greater than 50% TBSA. It is possible that providing pliable tissue to severely injured extremities may accommodate growth. This concept was the intent of Cho and colleagues, who performed free fasciocutaneous perforator flaps for foot reconstruction in 28 children younger than 14 years. Flaps expanded considerably, and no limb length discrepancy was identified in this cohort. But no controlled trials are likely ever to be performed comparing this approach with skin grafting alone. Thus, the choice of operation for lower extremity reconstruction continues to follow standard algorithms in children and adults at this point. Increased vigilance during periods of rapid growth is indicated focusing on loss of range of motion, deformity, joint subluxation, pain, or ulcerations.

Skin

The skin of newborns contains all 5 strata of mature skin from stratum basale to stratum corneum. But the skin of the very young is delicate in a variety of ways. The dermis is thin with less tensile strength, slowly increasing over time. Perforating vessels supplying skin in children are small in caliber compared with adults. Neurovascular immaturity can predispose to vasospasm with manipulation. Volume to surface area ratio is high, and sebum production is diminished. Hence, small children have a less effective barrier mechanism, prone to dessication. Overall, pediatric skin is delicate and sensitive, making complex manipulation daunting. And yet the history of plastic surgery is replete with successful reconstructions of the highest complexity. Several factors make this possible.

Although dermis in the very young is thin, split-thickness skin graft harvest is technically straightforward, healing rapidly after harvest. This healing is facilitated by an excellent blood supply and the inherent vitality of youth. Tumescence is particularly useful in achieving a favorable tissue turgor for skin graft harvesting. Perfusion and mechanical properties also facilitate local rearrangement in small children. Although vasospasm has been noted in pediatric replants as well as in perforator flaps, this is reliably managed through optimization of volume status, temperature, pain control, anxiety, and medications, such as chlorpromazine. And although the pedicles themselves may be relatively small, numerous investigators note that perforators even in infants are larger than one would otherwise expect rendering free perforator flaps practical. Additionally, small children lack the medical comorbidities of vascular disease, diabetes, or the smoking history of adults. In summary, although the tissues of small children are small and delicate, the inherent vitality, rich vascularity, and freedom from comorbidities make reconstructions of the highest order technically possible. Knowing which operation is best is a much more difficult question to answer.

From a wound-healing perspective, the first 6 months of life are marked by fine scars. But older children show a propensity toward exuberant hypertrophy, inflammation, and contracture. This propensity characterizes the immediate postburn course of many children, even impairing reconstructive outcomes. A beautiful flap may be interposed into the face only to be marred by border scar hypertrophy in the exuberant tissues of a child.

Face

Maxillofacial growth and development are also pertinent to burn reconstruction. Whereas the cranial vault nears 85% of growth by 3 years of age, maxillary growth continues into the early teens with mandibular growth continuing into the late teens. Burns resulting in tight facial scars can impair growth and development, including cross bites, open bites, constricted upper or lower arches, impaired mandibular movement, temporomandibular joint function, and even ankyloglossia with impaired speech. Hence, a multidisciplinary approach is important in the care of the child with severe facial burn scars.

Facial reconstructive needs are generally identical to adult care. Cicatricial ectropion is treated with anterior lamella release and full thickness skin grafting. Large surface area demands in the central face can be supplied with expanded full thickness grafts. Experience in the treatment of congenital melanocytic nevi of the central face is helpful in this regard.

The pendulum has swung away from cervicofacial tissue expansion to an extent because of the risk of distortion of facial anatomy and failure of expansion. Neale and colleagues’ candid 1993 summary of 37 cases of pediatric tissue expansion for the lower face and anterior neck highlights these pitfalls pointing out that alternatives to tissue expansion may be superior. Particularly useful take home points included the following:

  • Advancing expanded skin above the mandibular border should be done with caution because of the risk of distortion.

  • Flaps with vertical closures may have to be revised because of subsequent contraction.

  • Rotating down is preferable to rotating up when possible.

The combination of laser and local tissue rearrangement in series such as those of Donelan and colleagues and Hultman and colleagues demonstrate that severe, inflamed, hypertrophic facial scars do not necessarily have to be excised and that excellent results are possible through less invasive means today, without perturbation of important landmarks. Indeed not a few cases of tissue expansion for facial reconstruction may have been a net loss for patients. Beginning the treatment of facial burn scars with local tissue rearrangement and laser is a rational start that burns no bridges.

Oral commissure burns in children have diminished in frequency in the United States because of modern insulation of electrical wires. But occasional cases continue to present as well as international referrals. The most common presentation is of full-thickness loss of vermilion with lower lip involvement often exceeding the upper lip. Numerous approaches have been suggested, with donor tissue supplied from buccal mucosa, tongue, or from adjacent facial skin. Because of the variability of defects, no single design can be advocated. But standard principles include reconstitution of a continuous orbicularis and replacement of like tissues with like. Commissural contracture can be prevented to an extent if the design is not a simple line closure, incorporating a small Z-plasty or other interruption of the closure.

Severe nasal burns in the very young can be daunting, and many surgeons hesitate to undertake complex reconstructions early. Yet multiple reports attest to the practicality of nasal reconstruction in children using standard techniques, including forehead flaps and cartilage grafting. This reconstruction is a potential option when the forehead is spared, but this not common with severe burn injuries. Burget recommends free tissue transfer or pedicled scalp flaps for children with severe nasal burns. A valuable alternative has been described by the Boston Shrine team in a series of 28 cases. The scarred nasal dorsum is turned down then the skin grafted. Because of the stiffness present in the tissue, additional cartilage has not been necessary. And interestingly, the operation can be repeated for further advancement in an iterative fashion.

Pediatric scalp reconstruction bears no distinction from adult reconstruction, including standard options, such as tissue expansion. Autologous ear reconstruction is much the same for children and adults once the child has a chest circumference at the xiphoid level of at least 60 cm. Porous polyethelene reconstructions for a pediatric burn ear has been reported. And of course, prosthetics can be excellent options as well.

Breast

The breast bud in children lies 4 to 8 mm beneath the skin and is attached to the nipple by the pars infundibularis of the milk ducts. As many investigators have noted, every effort should be made to preserve the breast bud in pediatric burn excision.

Between 9 and 12 years of age, thelarche begins through hormonal stimulation, particularly ovarian estrogen with breast development reaching maturity between 2 and 4 years later. Although many systems are impacted by the pathophysiology of burn, secondary sexual development has not yet been identified as one of them. Indeed, as noted by McCauley and colleagues, breast development is remarkably resilient, even in the face of loss of the nipple areolar complex.

Definitive reconstruction tends to be reserved until the midteens or later and, therefore, is more of a topic for adult reconstruction. But before thelarche, a concerted effort is made to protect the breast from the deforming forces of tension. Common sources of tension include the surrounding thorax, the axilla and arm, and the neck. Hence, comprehensive care of burn scar contractures will protect the breast as well.

With respect to the breast itself, laser has become an integral part of many practices. Fat grafting is being explored in multiple centers to treat deep scar. Following thelarche, patients with an intact breast bud may develop an entrapped breast, whereby growing breast tissue is restricted by incompliant scar. This development is treated with release down to deep fascia and closed with skin grafts with or without dermal matrix. For severe deformity, or in patients without an intact breast bud, reconstruction may require the full gamut of techniques to create a breast mound. This reconstruction is deferred until maturity.

Axilla

Being the most proximal of the upper extremity joints, loss of shoulder range of motion is profoundly debilitating. Severe unilateral contractures can produce scoliosis in the growing child. And the constrictive effect on the developing chest can result in breast asymmetry and displacement of the nipple-areolar complex. Classification of the pediatric axillary contracture echoes that of adults. Multiple schemata have been offered, but all divide contractures based on their involvement of the following:

  • Anterior axillary fold

  • Posterior axillary fold

  • Dome

  • Surrounding tissues of the back or chest

With respect to timing, Greenhalgh and colleagues reported that axillary contracture release “as soon as they appear” curtailed the duration of morbidity but led to similar long-term outcomes. Once conservative and preventative therapies have failed to prevent a clinically significant axillary contracture, correction is indicated.

With respect to choice of operation, the best available data at present are limited to case series and expert opinion. Sison-Williamson and colleagues reported a nonrandom prospective case series of pediatric axillary contracture releases performed exclusively with incision followed by split-thickness skin grafts. The severity of the burn contractures was not explicitly reported. Yet effective and durable results were demonstrated in children with TBSA averaging 40%.

Similarly, Greenhalgh and colleagues’ 1993 series noted earlier also demonstrated good improvements in range of motion with split-thickness skin grafting. Dermal substitutes also remain a viable adjunct to skin grafting, but concerns regarding infection continue to be an issue.

Local tissue rearrangement for pediatric axillary contractures is well attested. A wide array of designs has been described, including standard Z-plasties, Huang’s three-quarter Z-plasty, Ogawa and colleagues’ square flap, and Grishkevich’s interdigitating trapezoidal flaps.

An enthusiastic advocate for local tissue rearrangement, Huang emphasized that introducing even relatively small flaps of well-vascularized pliable skin into a thickened contracture would interrupt lines of tension resulting in a de-escalation of the biology of the scar and result in improvements in surrounding tissues.

Severe contractures involving most of the axilla and surrounding tissues in children have been approached from every rung of the reconstructive ladder. Numerous investigators use perforator flaps from the scapular region in children with severe axillary scar contractures. Hocaoglu and Aydin demonstrated an impressive series of large pre-expanded perforator flaps from the back in children and adolescents with axillary contractures. Two 6 year olds were included in this group demonstrating proof of concept for this approach. Bulk is often cited as a major downside to flap-based axillary release, necessitating debulking. Overall, data are lacking to support firm recommendations. At this point, the reconstructive surgeon must treat the severe pediatric axilla somewhat empirically based on traditional principles for assessment of the tissue deficit.

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Nov 21, 2017 | Posted by in Dental Materials | Comments Off on Pediatric Burn Reconstruction
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