Background and Objectives Chronic pain affects between 30% and 50% of the world population. Our objective was to estimate the prevalence of chronic pain in Brazil, describe and compare differences between pain types and characteristics, and identify the types of therapies adopted and the impact of pain on daily life. Methods Cross-sectional study of a population-based survey with randomized sample from a private database. The interviews were conducted by phone. 78% of the respondents aged 18 years or more agreed to be interviewed, for a total of 723 respondents distributed throughout the country. Independent variables were demographic data, pain and treatment characteristics, and impact of pain on daily life. Comparative and associative statistical analyses were conducted to select variables for nonhierarchical logistic regression. Results Chronic pain prevalence was 39% and mean age was 41 years with predominance of females (56%). We found higher prevalence of chronic pain in the Southern and Southeastern regions. Pain treatment was not specific to gender. Dissatisfaction with chronic pain management was reported by 49% of participants. Conclusion 39% of interviewed participants reported chronic pain, with prevalence of females. Gender-associated differences were found in intensity perception and interference of pain on daily life activities.

Laser irradiation caused an immediate decrease in low back pain post-procedure similar to pain reduction caused by lidocaine injection. Both lidocaine injection and laser irradiation were more effective than radiofrequency treatment for immediate and longer term (1 month post-treatment) chronic back pain. Lasers Surg. Med. 48:653-659, 2016. © 2016 Wiley Periodicals, Inc.

BACKGROUND AND OBJECTIVES: Inflammation is a defense response of the body to a cellular damage caused by physical, chemical or biological agents, which triggers, among other factors, pain. Although inflammation plays an important role in the protection and regeneration of tissue injury, inflammatory pain results in decreased quality of life. In view of this, the development of safe and less invasive forms for the treatment of inflammatory pain is of great importance. The objective of this study was to evaluate the antihyperalgesic potential of the culture supernatant of keratinocytes and human fibroblasts in an experimental model of inflammatory hyperalgesia. METHODS: Evaluation of carrageenan induced inflammatory hyperalgesia through the use of electronic von Frey in animal models treated with culture supernatant of keratinocytes and fibroblasts. RESULTS: Local administration of naloxone, a nonselective opioid antagonist, in peripheral tissue, has been observed to inhibit the antihyperalgesic effect of the keratinocyte culture supernatant. Fibroblast culture supernatant on days 1 and 3 reverses for 2 hours the carrageenan induced inflammatory hyperalgesia, which is mediated by µ opioid agonist. CONCLUSION: This study indicates that culture supernatant of fibroblasts and keratinocytes is capable of inducing antinociception in inflammatory hyperalgesia, mediated by the release of Evaluation of the keratinocytes or fibroblasts culture supernatant in an inflammatory hyperalgesia model Avaliação do sobrenadante da cultura de queratinócitos ou fibroblastos em modelo de hiperalgesia inflamatória

Tramadol is a drug used to treat moderate to severe pain. It is known to present a peripheral effect, but the local mechanisms underlying its actions remain unclear. The role of peripheral opioid receptors in postoperative pain is not well understood. In the present study, we examined the peripheral opioid receptors to determine the local effect of tramadol in a plantar incision pain model. Rats were subjected to plantar incision and divided into four groups on postoperative day (POD) 1: SF_SF, 0.9% NaCl injected into the right hindpaw; SF_TraI, 0.9% NaCl and tramadol injected into the right hindpaw; SF_TraC, 0.9% NaCl and tramadol injected into the contralateral hindpaw; and Nal_Tra, naloxone and tramadol injected into the ipsilateral hindpaw. To determine the animals’ nociceptive threshold, mechanical hyperalgesia was measured before incision, on POD1 before treatment and at 15, 30, 45, and 60 minutes after the incision. The same procedure was repeated on the POD2. The expression levels of μ-opioid receptor (MOR) and δ-opioid receptor (DOR) were obtained through immunoblotting assays in the lumbar dorsal root ganglia (L3–L6) in naïve rats and 1, 2, 3, and 7 days after the incision. Our results showed that the plantar incision was able to cause an increase in mechanical hyperalgesia and that tramadol reversed this hyperalgesia on POD1 and POD2. Tramadol injections in the contralateral paw did not affect the animals’ nociceptive threshold. Naloxone was able to antagonize the tramadol effect partially on POD1 and completely on POD2. The DOR expression increased on POD2, POD3, and POD7, whereas the MOR expression did not change. Together, our results show that tramadol promoted a local analgesic effect in the postoperative pain model that was antagonized by naloxone in POD2, alongside the increase of DOR expression.

BACKGROUND AND OBJECTIVES: Most adults have several low back pain episodes during their lives. Ozone therapy is a minimally invasive method able to promote analgesia for most patients, with few reports of complications. This study aimed at reviewing the literature on the use of ozone therapy to treat low back pain and lumbosciatic pain. CONTENTS: Virtual Health Library was searched using the following keywords: ozone, therapy, pain, back, lumbodynia. Search sources included: LILACS, Medline, Cochrane, Pubmed, Ibecs and scientific journals, looking for articles originally published in English, Spanish and Portuguese in recent years. Fifty-four articles were selected. Two were randomized multicenter studies, four were systematic reviews, one was a meta-analysis with more than 8 thousand patients from different centers, one was a national Italian consensus, many were double-blind studies, some had control groups and many were observational studies. The level of evidence to support a stronger recommendation is still low (II-3 for intradiscal administration and II-1 for paravertebral or intraforaminal muscular administration), however this scenario seems to be dynamic with a trend toward the indication of ozone therapy. CONCLUSION: Ozone therapy was effective to treat low back pain with our without sciatic pain, being associated to few adverse events.