Laser Therapy for Pediatric Burn Scars: Focusing on a Combined Treatment Approach

Transcription

1 ORIGINAL ARTICLE Laser Therapy for Pediatric Burn Scars: Focusing on a Combined Treatment Approach Jennifer Zuccaro,* MSc, Inga Muser, BSc,* Manni Singh, BSc,* Janelle Yu, BSc,* Charis Kelly, RN (EC), MN, NP,* Joel Fish, MD, MSc, FRCSC* Treatment with laser therapy has the potential to greatly improve hypertrophic scarring in individuals who have sustained burn injuries. More specifically, recent research has demonstrated the success of using pulsed dye laser therapy to help reduce redness and postburn pruritus and using ablative fractional CO 2 laser therapy to improve scar texture and thickness. This study describes our early experience using laser therapy in our pediatric burn program and details our specific treatment approach when using each laser individually and in combination during the same procedure. A retrospective before after study of patients with hypertrophic burn scars who were treated with laser therapy at our pediatric institution was performed. One hundred and twenty-five patients were treated over a total of 289 laser sessions with more than 50% of patients under the age of 5 years at the first treatment. The majority of procedures were performed using both the pulsed dye and CO 2 lasers in combination. Before after Vancouver Scar Scale scores decreased from 7.37 (SD, 2.46) to 5.76 (SD, 2.29) after a single treatment. The results obtained from this study support the use of laser therapy to improve hypertrophic burn scars in the pediatric population. Rigorous randomized controlled trials are needed to confirm the effectiveness of this therapy. (J Burn Care Res 2018;39: ) BACKGROUND Laser therapy is a new form of scar treatment that can improve the physical symptoms that are associated with hypertrophic scarring. 1 At present, there are many different medical lasers available; however, two lasers, in particular, are often used to treat hypertrophic scars. Namely, the pulsed dye laser (PDL) can be used to reduce scar redness and pruritus, while the ablative fractional CO 2 laser (AFCL) can improve the overall texture and thickness of the scar. 1 3 An important advantage of using laser therapy to treat hypertrophic scars is that both PDL and AFCL can be safely combined at the same procedure to sequentially treat From the *Department of Plastic and Reconstructive Surgery, Hospital for Sick Children and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada. Conflict of interest statement. None declared. Address correspondence to Jennifer Zuccaro, MSc, Department of Plastic and Reconstructive Surgery, Hospital for Sick Children, 555 University Avenue, Suite 5420 Toronto, Ontario M5G 1X8, Canada. jennifer.zuccaro@sickids.ca American Burn Association All rights reserved. For permissions, please journals.permissions@oup.com X/2017 doi: /jbcr/irx008 different symptoms. 1 Unlike conservative treatments such as pressure garments or silicone applications that slowly improve the scar over time, laser therapy has the potential to produce significant improvements in as little as one session. 2 Moreover, scar-related outcomes following treatment with laser therapy can be formally evaluated using a range of subjective and objective scar assessment tools. 4 Laser therapy was first introduced in our pediatric burn program for the treatment of hypertrophic burn scars in Since its introduction, we have treated over 100 patients. This study describes our early experience using laser therapy for children with hypertrophic burn scars and details our specific treatment approach when using each laser individually (PDL or AFCL) and, more commonly, in combination (PDL and AFCL). METHOD Study Characteristics This study was performed at a single pediatric institution in North America. Our institution has the largest pediatric burn program in Canada and was verified by the American Burn Association in 2013 as 457

2 458 Zuccaro et al May/June 2018 a pediatric burn center. In addition, we are the only Canadian pediatric hospital to offer laser therapy as a treatment option for hypertrophic burn scars. Institutional Research Ethics Board approval was obtained before commencing this study. A retrospective before after review was then performed for all patients who received laser therapy for their burn scars from January 2014 to May Although some patients may have received acute burn care at other institutions, all laser therapy procedures and subsequent follow-up visits were performed in our burn program. Included in this study were patients who had received at least one session of laser therapy to treat a hypertrophic scar resulting from a burn injury during the study period. Cases in which laser therapy was used to treat scars resulting from other etiologies (ie, trauma, surgery) were excluded. During the study period, 125 patients were treated over a total of 289 laser procedures. Data Collection Relevant demographic data (age, sex, and Fitzpatrick skin type), burn details (etiology and total body surface area), before after Vancouver Scar Scale (VSS) scores and before after Toronto Pediatric Itch Scale (TPIS) scores were collected. The VSS is a widely used burn scar assessment tool, 5 while the TPIS is a validated postburn pruritus scale for use in children aged less than 5 years. 6 Information regarding the type(s) of laser used (including specific settings) and timing between procedures was also collected. IBM SPSS v23.0 was used to analyze the data. Descriptive statistics were used to summarize the data, and t tests were used to compare before after TPIS scores and VSS scores. In addition, several subgroup analyses modeled after a study by Hultman et al were also performed to learn more about timing of therapy, age at treatment, and type of laser used. 2 P <.05 indicated statistical significance. Treatment Approach At our institution, the decision to offer laser therapy is made by medically trained members of the burn team (surgeon, nurse practitioner, physiotherapist, and occupational therapist). The majority of patients who have been diagnosed with a hypertrophic burn scar are eligible to receive laser therapy and are only excluded if 1) they have a concomitant skin condition that could be exacerbated by the laser (chronic skin condition and/or history of severe keloid scarring), 2) they cannot tolerate the sedation used to perform procedures, or 3) it is deemed unnecessary by the patient/caregiver or clinician (ie, minimally symptomatic scar in nonfunctional area). The number of laser sessions recommended to each patient is dependent on several factors including symptom severity, functional impact, scar size (more sessions are needed to treat larger scars), response to initial treatment, and patient/caregiver opinion. Every laser therapy procedure is performed by a single burn surgeon and nurse practitioner in an operating room or in a procedural sedation room under intravenous sedation to minimize pain. The findings from a quality improvement project to assess the anesthetic practices used to carry out laser procedures in our burn program have been previously published. 7 The lasers used in our practice include a 595-nm Pulsed Dye Laser (Syneron Candela VBeam Perfecta, Wayland, MA) and an 10,600 nm ablative fractional CO 2 laser (Syneron Candela CO 2 RE, Wayland, MA). As noted, PDL is typically used to help reduce erythema and pruritus, while AFCL is used to improve scar texture and thickness. 1 3 The type(s) of laser used in each procedure and the corresponding laser settings are primarily dependent on the characteristics of the scar. For example, for scars that are very firm and thick (>5 mm in height), AFCL settings are adjusted for deep ablation and two to three pulses of the laser are stacked directly on top of one another (referred to as stacking or double/triple pulsing ). Each patient s Fitzpatrick skin type is also used to inform laser settings before treatment. To prevent complications such as blistering or dyspigmentation when treating darker skin, the PDL settings for fluence are lowered because of increased energy absorption by melanin. 8 In our burn program, each laser is used individually (PDL or AFCL) or in combination during the same procedure (PDL and AFCL). A combined approach is typically used in cases where patients have symptoms that would benefit from the use of both lasers (ie, scars that have erythema and/or pruritus and/or abnormal texture and/or increased height). During procedures in which both lasers are used, PDL is always used first, followed by AFCL. Typically, each site is treated with a single pass of each laser unless the scar is very thick in which case the aforementioned AFCL stacking method may be used. Topical lidocaine ointment (5%) is applied to the scarred area for all patients following each laser treatment, while topical triamcinolone (40 mg/ ml) is only applied to patients who are treated with AFCL. The justification and approach for applying topical triamcinolone to scars treated with AFCL has been previously outlined by Waibel et al. 9 Following each laser treatment, petroleum jelly-impregnated gauze is applied to the treated area and covered with a dry dressing and secured with tape. The dressing

3 Volume 39, Number 3 Zuccaro et al 459 is removed after 24 to 48 hours, and the treatment area is cleaned with soapy water and covered with a new moist dressing once a day for 3 to 5 days. After this time, the treatment area can continue to heal without a dressing. Patients are not given prescription pain medication or antibiotics following the procedure but are advised to use acetaminophen or ibuprofen if mild discomfort occurs. RESULTS One hundred and twenty-five patients received laser therapy for the treatment of hypertrophic burn scars during the study period. The mean age at treatment was 6.62 years (SD, 5.36), and the mean TBSA of the burn was 13.1% (SD, 12.2). Specific patient demographic information is included in Table 1. Two hundred and eighty-nine laser sessions were performed, with the majority of patients receiving two to three treatments (62%). The mean interval between the injury and first laser was 31.9 months (range: months). The mean interval between the first two laser therapy treatments was 4.8 months (range: 1 20 months). All patients were treated with either PDL (n = 7), AFCL (n = 117), or both PDL and AFCL (n = 165). The mean fluence used for PDL was 6.45 J/cm 2 (SD, 1.10; range: 5 9 J/ cm 2 ), and the mean core energy setting for AFCL was mj (SD, 1.88; range: mj). The two most commonly used settings for AFCL were fusion and deep modes. In total, 51 patients with 71 scarred areas had completed before after VSS scores for at least one procedure. As shown in Table 2, before after total VSS scores decreased from 7.37 (SD, 2.46) to 5.76 (SD, 2.29) after a single treatment (P <.005). In addition, each individual aspect of the VSS (pigmentation, vascularity, pliability, and height) also significantly decreased between each session (P <.05). Several subgroup analyses modeled after the study by Hultman et al were also performed including early vs late treatment timing (<12 months from injury vs >12 months from injury) and younger vs older at first laser session (<5 years of age vs >5 years of age). 2 The results of these analyses are shown in Tables 3 and 4. In the early vs late treatment group analysis, significant differences in scores for overall VSS scores were observed before each laser session (P <.05), while in the younger vs older analysis, there were no significant differences in overall VSS scores (P >.05). Lastly, before after TPIS scores (range: 0 4) for patients aged 5 years or younger are shown in Table 5. Table 1. Patient demographics DISCUSSION n % Gender Male Female Age Fitzpatrick skin type I. White or very pale skin II. Pale white with beige tinted skin III. Beige to light brown (olive) skin IV. Light to moderate brown skin V. Medium to dark brown skin VI. Dark brown to black skin Missing Etiology Scald Fire/flame Contact Chemical Friction Total body surface area (%) > Missing Survival following a burn injury has been greatly increased because of advances in burn care. Despite improvements in acute care, however, many patients may still develop hypertrophic scars that have permanent functional and social implications. 4,10 Hypertrophic scarring occurs when the normal healing process is disrupted causing increased inflammation, issues with wound repair, and excess collagen accumulation. 11 As a result, hypertrophic scars are typically characterized by their red appearance, rigid and raised texture, and clinical symptoms such as pruritus and pain. 10,11 Conservative treatment for hypertrophic scars is compromised of a range of therapies that may include any of the following: range of motion exercises, massage, pressure garments, steroid injections, and silicone applications; however, the effectiveness of these therapies is often variable as patients may respond differently to each treatment and compliance is difficult to measure. 12,13 Thus, burn care specialists

4 460 Zuccaro et al May/June 2018 Table 2. Before after Vancouver Scar Scale scores VSS Component, n = 71 Pigmentation Vascularity Pliability Height Total VSS Before 1.56, SD , SD , SD , SD , SD 2.46 Before 1.32, SD 1.0 across North America have begun to investigate more novel scar therapies. Laser therapy is a new form of scar treatment that can specifically target the symptoms associated with hypertrophic burn scars. More specifically, PDL and AFCL have emerged as beneficial modalities for treating hypertrophic scars. 1 PDL can reduce scar redness by selective photothermolysis of blood vessels thereby reducing hypervascularity. 14,15 In addition, PDL may also be used to help reduce pruritus. 1,16 Although the mechanism through which PDL reduces pruritus remains unknown, Allison et al have suggested that it may be the result of a change in scar regulatory chemicals. 16 Alternatively, AFCL can be used to help correct the texture and thickness of scars and may also help restore function in the scarred area. 1,2,17,18 AFCL has the capacity to vaporize sections of scar tissue thereby stimulating collagen remodeling and improved wound healing. 1,17 In this study, we demonstrate that PDL and AFCL can be used to improve hypertrophic burn scars in a pediatric population. In particular, significant improvements in mean overall VSS score and its individual components (pigmentation, vascularity, pliability, and height) were observed. These results align well with conclusions made by similar P < , SD 0.68 < , SD 0.91 < , SD 0.83 < , SD 2.29 <.005 Table 3. Before after Vancouver Scar Scale scores in early vs late treatment groups n = 70 Total VSS <12 mo post injury (n = 36) 8.63, SD , SD 2.34 >12 mo post injury (n = 34) 6.11, SD , SD 2.0 P <.05 <.05 Table 4. Before after Vancouver Scar Scale scores in young vs old treatment groups n = 71 Total VSS <5 y at first laser (n = 39) 7.62, SD , SD 2.29 >5 y at first laser (n = 32) 7.06, SD , SD 2.30 P NS NS Table 5. Before after Toronto Pediatric Itch Scale scores TPIS score n = (SD 0.70) 0.35 (SD 0.74) <.005 studies investigating the use of laser therapy for burn scars. 2,18,19 Moreover, the results of the subgroup analyses show that both young children and older children can benefit from laser treatment. In addition to improving VSS scores, treatment with laser therapy was also found to improve overall TPIS scores in a subset of patients in our study. Given that the TPIS can only be used for children under the age of 5 years, we were unable to evaluate the effect of laser therapy on pruritus in older patients. To improve our understanding regarding the use of laser therapy to treat postburn pruritus in older children, we plan to integrate the validated Itch Man scale into our standard practice. 20,21 One of the unique aspects of this review is that the majority of laser procedures were performed using both PDL and AFCL at the same session as opposed to using each laser individually. It is worth noting that this is one of the few studies that addresses how both PDL and AFCL can be safely combined at the same procedure. 1,22 Moreover, it is the first review to our knowledge to detail how this combined technique can be used to treat pediatric patients. Using both lasers at the same procedure is advantageous for numerous reasons. First, using a combined approach reduces the overall number of treatments required per patient as it allows the clinician to treat the different symptoms that are targeted by each individual laser in one session as opposed to two. Given that intravenous sedation is used in all laser procedures performed in our burn program, undergoing fewer laser sessions is highly beneficial to the patient and their family. Combining both lasers at the same session decreases the number of times a patient must receive sedation and also P

5 Volume 39, Number 3 Zuccaro et al 461 decreases the number of times a family must make arrangements to visit the hospital for procedures. In addition, using a combined approach to treat hypertrophic burn scars is practical and does not cause the clinician operating the laser undue burden. Instead, it allows the clinician to use the additional procedure time gained from combining treatments to treat a greater number of patients. Lastly, combining PDL and AFCL is a safe practice. This finding is supported by an expert panel in burn care who recommend that PDL and AFCL may be safely used in alternating or combined procedures. 1 Although patient safety was not formally studied in this review, we did not observe any major adverse events during the study period. The complications that were observed were minor and included several cases of folliculitis, one case of blistering, and one machine malfunction. Despite the success of this study, there are several important limitations that must be considered. First, given that individuals who assessed the scar at each laser session were the same clinicians who performed the procedures (burn surgeon and nurse practitioner), the potential for rater bias must be considered. Although the raters were blinded to the VSS scores they assigned at previous laser sessions, it is possible that they could have been biased toward favoring laser therapy given its recent introduction in our burn program. To remedy this issue, future studies must use blinded raters who are independent of the study team. Another limitation to consider is that although the VSS is a widely used scar scale, it does not provide any information regarding 1) how the patient perceives their scar and 2) objective changes in scar symptoms following laser treatment. Furthermore, Blome-Eberwein et al have also suggested that the VSS may not sensitive enough to detect minor changes in scarring. 4 Integrating patient-reported outcome tools such as the Patient and Observer Scar Assessment Scale as well as objective scar assessment tools such as ultrasound to measure scar thickness will provide a more comprehensive assessment of the scar than the VSS alone. 4,23 25 A final limitation to consider is that because this was a retrospective review, some of the records included in the analysis were incomplete or had missing data. In addition, the follow-up period was not standardized and therefore differed for each patient. It is well known that most scars will naturally improve over time; thus, without a standardized end point, it is impossible to disentangle the effect that time and the laser treatment itself have on improving scar symptoms. Implementing a follow-up visit at least 1 year after laser treatment has been stopped will provide us with a standardized end point for assessment and help minimize confounding. That being said, deciding how many sessions of laser therapy to offer or when to discontinue laser treatment also remains challenging. First, it can be difficult for a clinician to predict whether or not an additional session of laser therapy will continue to produce a positive result. Second, defining what it means to have a positive result following treatment with laser therapy is unclear. Aside from evaluating the physical symptoms associated with scarring, the patient s opinion of their scar must also be taken into consideration. For example, if the redness of a scar has significantly improved according to the VSS yet the patient still feels self-conscious about the appearance of their scar, should this be considered a positive result or a lack of response? Future research is still needed to determine laser treatment algorithms that can help clinicians decide when to discontinue laser therapy. Given the limitations, it is clear that a rigorous randomized controlled trial (RCT) must be performed to correctly evaluate the effectiveness of laser therapy for burn scars. The ideal RCT would integrate objective scar assessment measures, such as ultrasound, cutometry, colorimetry, as well as patient-reported measures, such as the Patient and Observer Scar Assessment Scale, to comprehensively assess all scar-related outcomes. A split-scar design in which half the scar is treated with laser therapy, while the other half is treated with standard care (patient = own control) would be optimal. However, recruiting pediatric patients to participate in such a study could be challenging because of the sedation required to carry out each procedure. CONCLUSION The information presented in this study contributes to the growing body of evidence that supports the use of laser therapy for hypertrophic burn scars. Overall, we observed significant improvements in the symptoms associated with hypertrophic scarring among patients treated with laser therapy. In addition, we demonstrated that combining PDL and AFCL at the same procedure can be highly advantageous for both the patient and the treating clinician. Future research should focus on proving the effectiveness of PDL and AFCL for hypertrophic scar treatment by carrying out rigorous, prospective RCTs. If future studies can confirm the effectiveness of laser therapy, burn clinicians may become more likely to invest in laser therapy for their patients, which could ultimately lead to a shift in standard scar treatment practices.

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