Treatment of postherpetic neuralgia with low-level laser irradiation: literature review

Abstract

Aims: To perform a literature review on the treatment of postherpetic neuralgia with low-intensity laser irradiation. Methods: The review was conducted in November and December 2015 by searching the terms "herpes zoster", "neuralgia", "low-level laser therapy", and "low-intensity laser therapy" in the LILACS, SciELO, and Medline databases. Full articles published in Portuguese, English, German, or Spanish between 2008 and 2015 were included. Incomplete articles, those that did not directly address the topic of interest, and those appearing in the same or in different databases were excluded. In the latter case, only one article was included. Results: Thirty-two studies were selected using the search terms. After the application of the eligibility criteria, 15 studies were read; two of them were excluded for being available in more than one database and one was eliminated for not adding relevant information. Therefore, 11 studies were included in the review: five of them conducted in the United States, two in Brazil, two in Germany, and two in Italy. There were four clinical trials, two systematic reviews and five case reports. The 11 studies found positive results after laser application, especially reduction of pain, with only one article mentioning little reduction of neuralgia. In the three studies that reported the irradiation parameters, these have not been uniform, with a medium wavelength of 740.6 nm, a medium power of 28 mW and a medium time of irradiation per point of 53.4 seconds. There was great variation in the number of sessions, with an average of about 12 sessions on alternate days. Conclusions: The low-intensity laser therapy provided positive results to patients with postherpetic neuralgia, however there is no consensus about the parameters to be used. In view of the different protocols, it is important to perform new studies in order to standardize the low-intensity laser therapy parameters applied to postherpetic neuralgia