European journal of pain : EJP
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Intra-articular hyaluronic acid (HA) injection, known as viscosupplementation, is a widely used therapy for pain relief in knee osteoarthritis (OA). Long-term clinical efficacy of HA has been reported in spite of a relatively short residence time. Herein, we evaluated our hypothesis that intra-articular HA injection could reduce the OA-associated changes in joint afferents. ⋯ Intra-articular HA injections reduced the severity of OA, decreased mechanical hyperalgesia of the paw, but not weight-bearing asymmetry, and attenuated OA-associated up-regulation of CGRP, but not TrkA and ASIC3, in joint afferents. The modulatory effects of HA on joint afferents is one of the underlying mechanisms of the gap between HA residence time and duration of clinical efficacy.
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Transcutaneous electrical nerve stimulation (TENS) is a non-invasive analgesic resource extensively used in painful conditions. However, preclinical studies suggest that the prolonged use of TENS results in the development of tolerance to its analgesic effect. The present study investigated the analgesic effect and development of tolerance to TENS with four different stimulation protocols. ⋯ The association between frequency variation and intensity at motor level promotes a delay in the development of analgesic tolerance to TENS, optimizing and extending its therapeutic effectiveness.
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Memory of chronic, acute and experimental pain may be inaccurate, but the research findings are inconsistent. The main aim of the study was to compare the memory of three types of pain and their associated affect. ⋯ The results of the current study suggest that memory of pain and affect is influenced by the meaning and affective value of the pain experience. This may help us to understand why the previous research on the memory of pain were so diverse.
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The 9-item STarT-Back screening tool was developed in primary care patients with low back pain (LBP) to identify those at greatest risk for chronic pain and requiring targeted treatment. We conducted a secondary data analysis study to examine the performance of comparable questionnaire items in a sample of primary care patients with well-defined acute LBP. ⋯ A risk classification schema using the recommended cut-off scores with items similar to the STarT-Back in a primary care population with strictly defined acute LBP had limited ability to identify persons who progressed to chronic pain. The results suggest caution when applying the STarT-Back in patients with acute LBP and a need to consider a modification of its cut-offs.
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Disturbed sleep and pain often co-exist and the relationship between the two conditions is complex and likely reciprocal. This 5-year prospective study examines whether disturbed sleep can predict the onset of multi-site pain, and whether non-disturbed sleep can predict the resolution of multi-site pain. ⋯ In conclusion, sleep could be relevant for predicting both the onset and the resolution of multi-site pain. It seems to be a significant factor to include in research on multi-site pain and when conducting or evaluating intervention programmes for pain.