Elsevier

Burns

Volume 30, Issue 4, June 2004, Pages 362-367
Burns

Low Level Laser Therapy—a conservative approach to the burn scar?

https://doi.org/10.1016/j.burns.2003.12.012Get rights and content

Abstract

Burn scars are known to be difficult to treat because of their tendency to worsen with hypertrophy and contracture. Various experimental and clinical efforts have been made to alleviate their effects but the problem has not been solved.

Since patients keep asking for Low Level Laser Therapy (LLLT) and believe in its effectiveness on burn scars, and since former studies show contradictory results of the influence of LLLT on wound healing, this prospective study was designed to objectify the effects of LLLT on burn scars.

Nineteen patients with 19 burn scars were treated with a 400 mW 670 nm Softlaser twice a week over 8 weeks. In each patient a control area was defined, that was not irradiated. Parameters assessed were the Vancouver Scar Scale (VSS) for macroscopic evaluation and the Visual Analogue Scale (VAS) for pruritus and pain. Photographical and clinical assessments were recorded in all the patients.

Seventeen out of 19 scars exhibited an improvement after treatment. The average rating on the VSS decreased from 7.10±2.13 to 4.68±2.05 points in the treated areas, whereas the VSS in the control areas decreased from 6.10±2.86 to 5.88±2.72. A correlation between scar duration and improvement through LLLT could be found. No negative effects of LLLT were reported. The present study shows that the 400 mW 670 nm softlaser has a positive, yet sometimes limited effect on burn scars concerning macroscopic appearance, pruritus, and pain.

Introduction

One of the major goals of surgical burn treatment must be the avoidance of excessive scarring. Once scars have formed, they are known to be difficult to treat because of their tendency to worsen with hypertrophy and contracture. Various experimental, conservative clinical and surgical efforts have been made but the problem has not been solved yet. Therapies such as surgical excision, dermabrasion, compression with silicone, and corticosteroids do not provide optimal results in the treatment of burn scars [1], [2], [3], [4].

As a clinician one makes the frequent observation that patients with burn scars often undergo a treatment with Low Level Laser Therapy (LLLT) by general practitioners or dermatologists after discharge from hospital. Being involved in the primary treatment as burn surgeons we are frequently confronted with the patients’ question about the effectiveness of this ‘paramedical’ strategy for burn scars.

Low-level lasers are defined by a power density at less than 500 mW/cm2 [5], [6], [7], [8].

According to experimental studies, low-level laser radiation activates individual cells via three principal effects:

  • 1.

    The photobiological action mechanism via activation of the respiratory chain: Primary photoacceptors are terminal oxidases as well as NADH-dehydrogenase.

  • 2.

    Activation of other redox chains in cells: In phagocytic cells irradiation initiates a nonmitochondrial respiratory burst (production of reactive oxygen species, especially superoxide anion) through activation of NADPH-oxidase located in the plasma membrane of these cells. The irradiation effects on phagoytic cells depend on the physiological status of the host organism as well as on radiation parameters.

  • 3.

    Indirect activation of cells via secondary messengers released by directly activated cells: Reactive oxygen species produced by phagocytes, lymphokines and cytokines produced by various subpopulations of lymphocytes, or NO produced by macrophages or as a result of NO-hemoglobin photolysis of blood cells [5].

In clinical studies, many investigators have found contradictory results of the effects of LLLT on wound healing. In laboratory animals accelerated wound closure, increased wound epithelialisation and improved tensile strength of scars were seen [9], [10], [11], [12]. Many other studies showed no improvement of the healing process through LLLT and the above mentioned effects could not be reproduced. Recently, an experimental study on rats was published with no significant improvement of the healing of burns injuries after LLLT [13].

However, the benefits of LLLT in wound healing are still controversial and in spite of many discussions about possible effects of low power laser light and widespread clinical application by general practitioners and dermatologists, the effects of LLLT on burn scars have not been the subject of clinical studies in human beings up to now.

This present prospective study was designed to objectify the effects of LLLT in the avoidance, prophylaxis, and treatment of burn scars.

Section snippets

Materials and methods

After approval by the Local Ethics Committee, 19 patients (14 male, 5 female, aged 18–77 years, mean 38±13.97) were included in the study (patient characteristics are summarized in Table 1). In each patient one burn scar was selected as lesion that should be irradiated, and one similar burn scar was defined as a control area that should stay untreated.

All patients had suffered from burn scars within 1–194 months prior to presentation. None of the patients had received treatments with

Results

Seventeen out of 19 lesions showed macroscopic improvement after the treatment (expressed in points on the Vancouver Scar Scale) (Fig. 2); two lesions did not improve. Before the treatment the scars that were to be radiated were classified on an average of 7.10±2.13 points on the VSS. This number decreased to 4.68±2.05 points after the treatment. The respective data of the control areas were 5.86±2.71 points before and 5.40±2.66 points after the treatment (Fig. 3). None of the scars became

Discussion

It is a general phenomenon that patients who suffer from clinical symptoms which are difficult to treat have the tendency to switch to ‘paramedic’ therapies. At present LLLT is still to be considered ‘paramedic’. As clinicians we have to be able to advise our patients if this particular therapy is helpful or might worsen their symptoms.

Recent studies in laboratory animals show diverging results of the effects of LLLT [9], [11], [13], [16]. Nevertheless, the present study clearly shows that LLLT

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