Effect of Erbium:YAG Laser Treatment on Scar Pain

Abstract

Scar pain has persisted as a significant problem for patients who have undergone surgery or suffered trauma. The pain may vary from what is described as irritation or itching to severe neuropathic pain. Recent work by dermatologists using lasers to treat scars for cosmetic reasons has revealed that there has been pain relief from the cosmetic laser treatment. This study examined the effect of a single erbium:YAG laser treatment on 23 patients with chronic (>6 months) scar pain. Assessment was at one month and four months post treatment. Results showed a significant and persistent decrease in McGill Pain Scale, Itch Visual Analog Scale, and Pain Intensity Scale. Treatment of chronic scar pain with readily available cosmetic lasers may be of significant benefit to patients who have not responded to standard injection therapy. This research was funded by the Department of Anesthesiology, LSU Health Sciences Center—Shreveport. Presented in part at the Joint International Laser Conference, September 21-23, 2003, Edinburgh, Scotland. BACKGROUND AND OBJECTIVE Scar pain may persist chronically after surgery or accidental trauma. Entrapment of neurons by collagen has been considered the most probable cause.1 Treatment has included infiltration with local anesthetic agents, steroids, electrical stimulation, and needles, all of which usually provide only short-term relief. An incidental finding in a study of cosmetic laser treatment of scars showed significant pain relief for four patients who also had pain.2 The objective of this study was to examine the effect of a single treatment with an erbium:YAG laser on chronic scar pain. STUDY DESIGN/MATERIALS AND METHODS After approval by the IRB at LSUHSC-Shreveport and informed consent, 23 patients with a history of chronic (>3 months) scar pain were studied. Demographic data collected included age, weight, height, sex, Fitzpatrick Scale (skin color), type of injury (accidental vs surgical), and location of scar. The Fitzpatrick Scale assesses skin color: A score of 1 represents very light skin, and a score of 5 represents very dark skin. Baseline assessments included McGill Pain Score (Figure 1), including sensory and affective pain descriptors, VAS pain scale, VAS itching scale, and a 5-point numerical intensity scale (0=none, 1=mild, 2=discomforting, 3=distressing, 4=horrible, and 5=excruciating). Figure 1 Figure 1: McGill Short Form.3 Yellow are sensory attributes; orange are affective attributes. All patients were treated with an Er:YAG laser (NaturaLaseTM, Focus Medical, Bethel, CT)(Figure 2), wavelength 2.94 nm, fluence 1.29 J/cm, spot size 8 mm, with 2 pulses per second, and 50% overlap. Assessment was at one month and four months post-procedure. Data were analyzed with repeated-measures analysis of variance, and a priori level of significance was defined at p When Manuskiatti, et al, studied the cosmetic effects of lasers on scars, they noted in passing that four of the patients they studied had complained of scar pain prior to the cosmetic treatment, but that after the treatment, the scars not only looked better, but the pain had vanished.2 They used a 585-nm pulsed-dye laser in their study. Kotani, et al1 hypothesized that nerve ending were entrapped by the formation of scar, causing the scar pain. If this is true, the laser could be simply destroying the collagen and causing it to regrow in a manner such that it no longer constricts the nerve ending. Recently, Martin has proposed that the laser may reduce directly chronic inflammation at the cellular level.4 Whatever the physics and physiology, cosmetic lasers are ubiquitous, and their potential application by anesthesiologists and pain medicine specialists to treat chronic scar pain represents a real breakthrough in this difficult area of pain medicine. CONCLUSION The Erb:YAG laser shows significant promise as a treatment modality for chronic scar pain.