Soft Tissue Trauma and Scar Revision




Numerous techniques and treatments have been described for scar revision, with most studies focusing on the adult population. A comprehensive review of the literature reveals a paucity of references related specifically to scar revision in children. This review describes the available modalities in pediatric facial scar revision. The authors have integrated current practices in soft tissue trauma and scar revision, including closure techniques and materials, topical therapy, steroid injection, cutaneous laser therapy, and tissue expanders.


Key points








  • Scars of the head and neck often have profound physical and psychosocial consequences in children; therefore, treatment should not be delayed in the pediatric population.



  • The goal of primary soft tissue trauma of the face is to prevent the need for scar revision by applying proper wound closure techniques.



  • The surgeon’s armamentarium to improve on the appearance of facial scars should be broad and should generally start from the least to most invasive modalities.



  • Treatment planning is an important aspect in children because successful outcomes depend not only on precise surgical technique but also on patient and family cooperation.






Introduction


Scars of the head and neck region can be physically and psychologically disfiguring. This cannot be emphasized enough in the pediatric population. Wound healing in young children and adolescents is crucial because excessive scarring can lead to low self-esteem and stigmatization. Scars may be the end product of elective or urgent surgery, burns, and trauma. Most superficial facial wounds heal with few long-term sequelae; however, interruption of the reticular dermis likely results in residual scarring.


The ideal scar after complete maturation is narrow, flat, and similar in color to the adjacent skin. Conversely, unfavorable scars are hypertrophic, have wide margins and are misaligned with relaxed skin tension lines. Patients should be made aware that their facial scars cannot be completely eliminated. Nevertheless, a plastic surgeon’s armamentarium should include a variety of techniques to minimize initial scar formation and treatments in which to improve on unfavorable scars. The successful application of these techniques requires an understanding of their ideal timing and indications.




Introduction


Scars of the head and neck region can be physically and psychologically disfiguring. This cannot be emphasized enough in the pediatric population. Wound healing in young children and adolescents is crucial because excessive scarring can lead to low self-esteem and stigmatization. Scars may be the end product of elective or urgent surgery, burns, and trauma. Most superficial facial wounds heal with few long-term sequelae; however, interruption of the reticular dermis likely results in residual scarring.


The ideal scar after complete maturation is narrow, flat, and similar in color to the adjacent skin. Conversely, unfavorable scars are hypertrophic, have wide margins and are misaligned with relaxed skin tension lines. Patients should be made aware that their facial scars cannot be completely eliminated. Nevertheless, a plastic surgeon’s armamentarium should include a variety of techniques to minimize initial scar formation and treatments in which to improve on unfavorable scars. The successful application of these techniques requires an understanding of their ideal timing and indications.




Management of primary soft tissue injury


The ideal management of facial scars is to prevent the need for scar revision in the first place. This begins with appropriate selection of suture material and meticulous handling of the soft tissue to avoid trauma or closure under tension. Surgeons can achieve this by working in an environment in which they are comfortable. Of equal importance is the ability of patients to tolerate the procedure in an emergency department or outpatient setting. When it comes to treating a pediatric facial lesion, it may be next to impossible to have a child hold reasonably still to achieve proper repair techniques. Procedural sedation is, therefore, an indispensable tool in this setting.




Procedural sedation


Pediatric procedural sedation refers to the pharmacologic technique of managing a child’s pain and anxiety during an uncomfortable procedure. Procedures that are attempted in an uncooperative child often require restraints, which create adverse procedure outcomes and undue stress for patients and families.


All children require a presedation assessment, which includes a focused medical history and physical examination to evaluate for risks of adverse events.


Fasting


The amount of time a child should be fasting before procedural sedation continues to be disputed. Two large prospective trials showed no significant difference in adverse events between fasting and nonfasting children. Several guidelines exist with differing recommendations regarding nothing-by-mouth timing; thus, the risks of immediate sedation must be considered in accordance with the urgency and nature of the procedure. Potential settings for procedural sedation include emergency departments, subspecialty procedure suites, and physician offices. All locations must have age- and site-appropriate medications and supportive equipment readily available.


Sedatives


A review of the emergency medicine literature illustrates that many medications and cocktails are available to provide pain relief, anxiolysis, or both for a child during procedural sedation.




  • Etomidate is a rapid-onset sedative with a short duration of action. It maintains hemodynamic and respiratory stability but reduces intracranial pressure.



  • Over the years, ketamine has become commonplace in pediatric emergency departments. The agent creates a dissociative state and provides effective sedation and analgesia. Contraindications include sympathomimetic medical conditions, elevated intracranial pressure, coronary heart disease, and a history of psychosis. Ketamine should not be administered to infants 3 months or younger secondary to risk or respiratory compromise.



  • Propofol is a rapid-onset, short-acting agent that offers sedation and antiemetic properties. It has no analgesic properties, however, and therefore warrants coadministration of another agent for pain control. The agent is a potent respiratory depressant and a reversal agent does not yet exist. Thus, it is prudent to monitor the respiratory status of patients under sedation with propofol and provide airway intervention if necessary.



  • A sedative combination is available that consists of 1:1 intravenous (IV) ketamine and propofol. Ketamine’s sympathomimetic properties act to counter the respiratory depression and hypotension seen with propofol whereas the latter counters ketamine’s emetogenic properties. Shah and colleagues conducted a randomized trial that suggested greater satisfaction with the sedative combination among patients and providers versus propofol or ketamine alone. Another randomized controlled trial comparing propofol alone with the combined agent found more patient and provider satisfaction but unchanged respiratory depression. Another group found that the propofol and ketamine combination provided more consistent sedation depth than propofol alone.



Administration of Sedation


Intranasal administration of sedative agents offers more rapid onset of action compared with IV or intramuscular administration, with less discomfort.


Intranasal midazolam can provide anxiolysis during simple procedures, including incision and drainage and minor laceration repair.


Inhaled nitrous oxide (N 2 O) is another option for pediatric procedural sedation. One prospective randomized study compared inhaled N 2 O and IV ketamine during laceration repair in children. The ketamine group had higher initial pain scores and more emesis than the N 2 O group; however, results may be biased secondary to IV placement in the ketamine group alone. A large prospective, observational study showed a good safety profile for sedation with N 2 O administered at 70% concentration by nasal mask for procedures of fewer than 15 minutes in children.




Suture material


Traumatic lacerations are among the most common reasons that children are seen in the emergency medical setting. Pediatric wounds must be closed with special attention to avoid excess tension. Skin elasticity is inversely proportional to patient age with a greater tendency to stretch into a wide scar over time. Local muscle tension and lesions over bony prominences as well as edema increase wound tension. Some wounds can be remedied with surgical adhesive tape and tissue glue but others require sutures depending on the location, size, and width of the defect. The use of absorbable suture and tissue adhesives obviates a return to clinic, thereby decreasing costs associated with missed work and school.


Traditional teaching dictates that nonabsorbable sutures be used for approximating the outermost layer of lacerations, especially those under tension. Several studies have challenged this approach, however. In a single-blind, randomized controlled trial comparing outcomes of traumatic pediatric lacerations repaired with absorbable plain gut and nonabsorbable nylon sutures in an emergency department, no difference was found in the rate of dehiscence or infection. Cosmetic results seemed at least as good as in wounds repaired with nonabsorbable nylon sutures. Parell and Becker compared rotational advancement flaps of the head and neck, in which half the wound was closed with 5-0 polypropylene and the other half with 5-0 polyglactin. At the 6-month mark, no difference was noted in scar formation. One study compared facial lacerations closed with rapid-absorbing gut suture, nylon suture, and tissue adhesive octyl cyanoacrylate and no differences in cosmetic outcomes were identifies at 9 and 12 months. Recently, Luck and colleagues compared nylon sutures with fast-absorbing catgut sutures in the repair of pediatric facial lacerations. In contrast to their previous study in which there was no difference in cosmetic outcomes between the 2 groups, physicians found better results at 3 months in the nylon suture group compared with the absorbable group. Caregivers in this study found no difference, however, with respect to the appearance of the scar. A meta-analysis of the pediatric literature suggested that nonabsorbable sutures were not superior to absorbable sutures in the management of wound repair but larger, methodically sound trials are warranted.


Meticulous technique and ideal suture selection are critical in the repair of the pediatric facial lesion. Other factors are beyond a surgeon’s control and include the mechanism of injury and position of the wound as well as a patient’s overall health, nutrition status, and tendency to form robust scars. Topical therapies have been investigated as potential adjuncts to decrease the severity of scar formation and to optimize wound healing.




Topical therapy


Scar prevention begins with the environment in which is it allowed to heal. In a closed wound, re-epithelialization occurs within 24 to 48 hours. The optimal milieu for wound healing is a moist environment because it encourages cell migration and can double the rate of epithelialization. Occlusive or semiocclusive dressings can be used to generate a moist environment and additionally can wick away excess fluid that can macerate surrounding tissue or encourage bacterial growth. Topical therapies for the prevention and minimization of scars remain an area of controversy. To date, no single topical treatment is touted as the ideal agent in the prevention or elimination of hypertrophic scars.


Vitamin E


Vitamin E consists of a group of fat-soluble tocopherol and tocotrienol derivatives with robust antioxidant properties. Vitamin E theoretically modulates scar formation by reduction of inflammation, fibroblast proliferation, and collagen synthesis. A prospective single-blind study compared postoperative twice-daily application of vitamin E to petrolatum in children. Based on assessments by an external surgeon and the caregiver, 96% of the treatment group showed better cosmetic results compared with 76% in the control group. A double-blind controlled study of 15 patients, however, who had undergone skin cancer excision, applied a petroleum-based ointment with and without vitamin E to the wounds twice daily for 4 weeks. In 90% of the cases, topical vitamin E either had no effect on or actually worsened the cosmetic appearance of scars and 33% developed a contact dermatitis. Given the paucity of scientific evidence available and risk of contact dermatitis, the routine use of topical vitamin E is generally not encouraged.


Allium cepa


Onion extract, or Allium cepa , has antiinflammatory, bacteriostatic, and fibrinolytic properties. The topical gel Mederma (Merz Pharmaceuticals, Frankfurt, Germany) contains 10% aqueous A cepa . Use of onion extract has been suggested to be efficacious in reducing various types of scars but such studies lack a proper control arm. A newer formulation of Mederma Advanced Scar Gel contains a higher concentration of onion extract along with a proprietary liposomal skin penetrator system. A clinical trial of this new formulation suggested improved overall appearance, redness, softness, and smoothness of treated lesions, but the control group had no topical treatment at all. Chung and colleagues conducted a randomized, double-blind, split-scar study of 24 patients who showed no scar improvement compared with a petrolatum ointment. Treatment of 17 scars after Mohs surgery had no statistically significant difference in erythema and pruritus after 1 month of thrice-daily applications and had better results with the petrolatum control group, which suggests that scar hydration plays a more important role in wound healing. At this time, there is insufficient evidence to support the routine use of onion extract as a topical therapy.


Silicone


Silicone is a soft, semiocclusive scar cover made of cross-linked polydimethysiloxane polymer with several available formulations. The mechanism of action in scar remodeling has not been well elucidated, although its healing properties are thought to stem from hydration, occlusion, reduced capillary activity, and fibroblast-induced collagen deposition. Silicone gel alone compared with silicone cream with occlusive dressing showed a 22% versus 82% decrease in erythema, tenderness, pruritus, and hardness, suggesting that the occlusive factor may be synergistic and that silicone sheeting may be more effective than silicone gel alone. A small study of children with hypertrophic scars treated with silicone sheeting showed that 3 of the 5 treated children showed initial improvements in scar size, thickness, softness, and vascularity ; however, adverse side effects included rash and skin breakdown. Silicone gel sheeting has been demonstrated to increase the elasticity of preexisting scars between 1 and 6 months. An international advisory panel has supported silicone gel sheeting as a primary option in the treatment of hypertrophic or keloid scars. Silicone gel sheeting, as opposed to silicone gel alone, seems efficacious in improving the appearance of new and preexisting hypertrophic scars.


If Topical Therapies Fail


Despite superb primary repair techniques and the use of topical therapies, the wound may not appear optimal in the eyes of the surgeon or family. It is then time to contemplate more invasive interventions to improve the long-term outcome of the final scar. Intralesional steroid administration is a useful office procedure that can soften and mold either a maturing primary scar or older matured scar into a less visible lesion.




Triamcinolone injection


Facial plastic surgeons wishing to maximize the management of their patients with facial scars should become comfortable with the use of intralesional scar tissue triamcinolone injections. For the purpose of this discussion, it is difficult to outline an exact formulation because there is great variability in judgment with the application of intralesional steroid injections. Nevertheless, general guidelines can steer a maturing facial plastic surgeon to develop a strong working knowledge on the use of this important office-based clinical intervention.


Indications for steroid injections include




  • Persistent tissue edema after scar revision



  • As adjunctive treatment of hypertrophic scars and keloids



Hypertropic scars and keloids are typically associated with a facial scar that rises above the natural surface level of the surrounding skin. Medical triamcinolone designed for injections typically comes in 2 standard concentrations. A surgeon starting to gain comfort with this procedure may start with a concentration of 10 mg/mL and should strongly consider diluting this to 2.5 mg/mL until confidence with this intervention is gained. For concentrations of triamcinolone at 2.5 mg/mL, the surgeon may inject 0.05 to 0.1 mL of medication per approximate linear 5 to 8 mm of scar tissue.


A key aspect to keep in mind when mastering this technique is that although it is always possible to bring a patient back for repeated injection sessions, it is impossible to uninject a patient. It is always more prudent to do multiple injections spread out over the course of several weeks or months than to accomplish maximum scar softening or flattening with a single injection. When a surgeon attempts to soften and/or flatten the scar with a single higher concentration injection, there is a risk of overflattening the area. Subcutaneous fat atrophy can additionally lead to a post-treatment divot in the treated area, which can be difficult to permanently reverse although cosmetic fillers can be a temporary remedy.


Timing of Steroid Injections


Injections are typically performed between 2- and 6-week intervals, with 4 weeks the most common time interval. Patients are advised to massage the treated area for approximately 24 hours after injection. The logic is that after the initial injection, the concentration of the antiinflammatory agent is at its highest, and patients should therefore be instructed to perform firm digital massage of the target area to gain maximum softening and flattening benefits.


Lip Scar Injections


Scars in the upper and lower lips are particularly amendable to steroid injection. The senior author has observed that over the course of many years of treating patients with routine lip lacerations, even after proper initial wound management and closure, patients often develop a firm, subcutaneous nodularity in the lip tissue. Typically, patients present with this finding 1 to 2 months after a successful lip laceration repair. Whether this is a result of the effect of the initial laceration on minor salivary gland tissue has not yet been fully elucidated. Patients may describe this phenomenon as a small bump in the affected tissues of the lip. This nodularity can be palpated on physical examination by performing a gloved examination with 1 finger inside the oral cavity to stabilize the tissue and a thumb pressing against the outer skin. These particular lesions respond effectively to triamcinolone injections. Again, this is an area where starting at a concentration of 2.5 mg/mL of triamcinolone is most prudent. As the surgeon develops experience with this technique, the concentration of triamcinolone injections can be increased to 10 mg/mL. The amount injected typically ranges from 0.05 to 0.2 mL during 1 session.


Risks with Intralesional Steroid Injections


Surgeons should always counsel patients on the risks of intralesional steroid injections, which include excessive subcutaneous fat atrophy that can create divots, telangiectasias of the surrounding skin, and thinning of the dermis. In the senior author’s experience, the negative side effects of intralesional steroids can be significantly reduced with injections completed at lower concentrations, performed at the appropriate time intervals and with close clinical follow-up.


Analysis of Treatment Options


The initial assessment of any scar in the office setting by a facial plastic surgeon should include analysis of the treatment options applying a reconstructive ladder model, which implies starting with the simplest treatments before seeking more invasive management options. Can the wound be managed simply with topical therapy, such as silicone sheeting? Or would intralesional steroids be more appropriate? More invasive options of a scar revision include laser application, dermabrasion, and surgical intervention.




Lasers


Laser therapy in children poses unique advantages as well as challenges compared with their adult counterparts. Pediatric lesions are often smaller and thinner. With aging, the composition of vascular and pigmented lesions becomes more resistant to laser therapy; therefore, treatment of lesions at an early age allows for enhanced results in fewer sessions. Laser parameters should be adjusted for smaller vessel caliber and the unpredictable nature of scarring in pediatric skin.


Laser-tissue interactions are guided by principles of selective photothermolysis, which include adequate fluence to damage the target tissue while minimizing collateral damage to surrounding tissue. A light wavelength is chosen that is selectively absorbed by tissues of interest, and a pulse duration is selected equal to or less than the thermal relaxation time of the target tissue to avoid conduction of thermal energy to surrounding tissues. This is defined as the time required for 90% of the tissue to cool to half of the temperature achieved immediately after laser exposure. The fluence, which is the energy density of the laser in J/cm 2 , should be sufficient to heat the target tissue. The choice of light wavelength and laser parameters depends on the scar size, color, texture, and classification.


Laser Selection for Scars and Keloids


The carbon dioxide (CO 2 ) and erbium:YAG (Er:YAG) lasers traditionally were used to treat hypertrophic scars and keloids. The pulsed dye laser (PDL) has become the preferred laser for these lesions. The proposed mechanisms of action include selective photothermolysis of vasculature, release of mast cell constituents that alter collagen metabolism, reduction of transforming growth factor β expression, fibroblast proliferation, and collagen type III deposition. The heating action of the PDL is also thought to disrupt disulfide bonds with subsequent realignment of collagen fibers. The PDL has been shown to improve scar size, erythema, pliability, pruritus, and texture; results of treatment on facial scars have been promising. Post-treatment purpura is the most encountered adverse side effect and can last for several days. Other postoperative complications include edema, vesiculation, and crusting. Hyperpigmentation has been reported in 1% to 24% of cases, and treatment should be resumed only after resolution to ensure extra melanin does not interfere with laser absorption.


Ablative Lasers


Depressed scars are caused by inflammation and collagen destruction with atrophy. The goal of laser treatment of these hypopigmented and fibrotic lesions is to decrease the appearance of scar borders while stimulating collagen deposition in the wound depression. Ablative lasers cause a photothermal effect with subsequent collagen contraction and remodeling that improves textural irregularities. Recontouring of the scar can be achieved with the Er:YAG or CO 2 lasers. Both are preferentially absorbed by intracellular water, but the shorter wavelength of the Er:YAG laser increases its absorption rate by 16-fold. Compared with the CO 2 wavelength, the Er:YAG light is associated with fewer pigmentary changes but may cause pinpoint bleeding due to inferior hemostasis. Side effects include erythema and edema with occasional serous discharge. The erythema typically appears worse in first several days with gradual resolution over the subsequent weeks. Hyperpigmentation, rather than hypopigmentation, is the more common side effect and is usually observed during the first 3 to 4 weeks post-treatment. The high cost and potential side effects may limit the use of ablative lasers in pediatric patients.


Nonablative Lasers


Nonablative lasers selectively target the dermis, thus sparing the epidermis. For this reason, nonablative lasers have a lower side-effect profile, which includes local erythema, edema, and, less frequently, herpes simplex reactivation or vesiculation. The tradeoff of the lower-risk profile is reduced clinical efficacy. Children and their families may find it challenging to comply with the 3 to 5 sessions required each month to achieve clinical results. Visible changes are noticeable within 3 to 6 months. The reduced side effects of nonablative lasers may be a better option because pediatric skin has a propensity to remain erythematous longer compared with adult skin, although more investigations in this area are warranted.


Fractional lasers create microcolumns of dermal necrosis surrounded by zones of viable tissue. The intact surrounding tissue acts as a reservoir of healthy epidermal and dermal cells that aid in wound healing. Fractional lasers are available in both nonablative and ablative forms. The nonablative fractional laser (NAFL) preserves the stratum corneum, thereby preserving the epidermal barrier. Superior clinical results can be obtained with greater energy settings and multiple laser passes, but a higher density is more likely associated with erythema, edema, and hyperpigmentation. Typically, patients require monthly treatments with more appreciable cosmetic results after each successive session.


Ablative Fractional Laser


The ablative fractional laser similarly creates laser microarrays in the skin but does not preserve the stratum corneum. Although there remain areas of viable epidermis to aid in healing, immediate post-treatment results are similar to purely ablative treatment, including severe erythema and serosanguinous drainage due to lack of protective columnar regions. Compared with NAFL, fewer sessions are required because most patients benefit from 1 to 2 treatments every 6 to 12 months. In a prospective study of 24 children with facial scars who underwent fractional CO 2 laser resurfacing, clinical improvement was found excellent in 58% and good in 29% of cases without adverse events.

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Aug 26, 2017 | Posted by in General Surgery | Comments Off on Soft Tissue Trauma and Scar Revision
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