European journal of pain : EJP
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Pain influences many aspects of daily living and effective analgesics should reinstate normal spontaneous daily behaviours. Experiments are described herein which show that the innate, spontaneous behaviour of burrowing by rats, which can be simply and objectively assessed by measuring the amount of gravel left in a hollow tube 1 h after presentation to the rat, is reduced by peripheral nerve injury (tibial nerve transection (TNT), L5 spinal nerve transection (SNT) and partial sciatic nerve ligation (PSNL)) and also following inflammation induced by intra-plantar injection of Complete Freund's Adjuvant (CFA). Gabapentin (100 mg/kg sc) but not at 30 mg/kg sc significantly reduced burrowing activity in naive rats. ⋯ The level of mechanical hypersensitivity in rats with peripheral nerve injury did not correlate with the deficit in burrowing indicating that different parameters of the holistic pain experience are measured in these paradigms. Gabapentin at 30 mg/kg sc, but not 100 mg/kg sc, reversed the deficit in burrowing induced by TNT and ibuprofen (30 mg/kg sc) reversed the effect of CFA on burrowing. These experiments show that measurement of burrowing is a simple, objective assay of innate rodent behaviour affected by pain that is ethologically relevant to the rat, does not rely wholly on evoking a reflex and can dissociate a selective analgesic dose of gabapentin from one inducing motor impairment in the same animal.
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Randomized Controlled Trial
Dose response of tramadol and its combination with paracetamol in UVB induced hyperalgesia.
Combining tramadol with paracetamol is an established analgesic treatment strategy. However, dosing and differential effects on peripheral and central hyperalgesia are still to be determined. After Ethics Committee approval, 32 volunteers have been included in this 2 phased, double blinded, placebo controlled, cross-over study. ⋯ Paracetamol also reduced secondary hyperalgesia, but no combination effect with tramadol could be shown. We conclude, in inflammatory hyperalgesia tramadol alone exerts only weak anti-hyperalgesia. Even adding a small dose paracetamol enhances thermal anti-hyperalgesia.
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Widespread pain (WSP) is common in the general population and is associated with poor outcomes. The aim of this study was to quantify the risk for medically certified disability pension from WSP. We further studied how other common physical symptoms, common mental disorders and functional limitations influenced this risk. ⋯ Further adjustments for other common symptoms, including mental illness, reduced, but did not abolish these risks. WSP is a major risk factor for disability pensions, and not only pensions for musculoskeletal disorders. The global impact of WSP, and its close association to other symptoms, suggests prevention of the severe occupational outcomes for this group must have a broad focus and move beyond symptom directed approaches.
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A significant proportion of patients experience chronic post-surgical pain (CPSP) following inguinal hernia surgery. Psychological models are useful in predicting acute pain after surgery, and in predicting the transition from acute to chronic pain in non-surgical contexts. This is a prospective cohort study to investigate psychological (cognitive and emotional) risk factors for CPSP after inguinal hernia surgery. ⋯ After controlling for age, body mass index and surgical variables (e.g. anaesthetic, type of surgery and mesh type used), lower pre-operative optimism was an independent risk factor for CPSP at 4 months; lower pre-operative optimism and lower perceived control over pain at 1 week after surgery predicted higher pain intensity at 4 months. No emotional variables were independently predictive of CPSP. Further research should target these cognitive variables in pre-operative psychological preparation for surgery.
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Randomized Controlled Trial
Painfully reassuring? The effects of validation on emotions and adherence in a pain test.
Communicating reassurance to patients with musculoskeletal pain complaints, but no red flags, presents a dilemma of dampening worry while refraining from reinforcing undue pain behaviors. Previous research shows that reassurance does not decrease negative affect and may be perceived as not taking the symptoms seriously. Validation offers an alternative where the patient's experiences and feelings are acknowledged and has demonstrated, for other problems, a decrease in arousal which may set the stage for behavioral change. ⋯ However, adherence was more than twice as high in the validation group as compared to invalidation. These results show that a relatively simple validation procedure had significant and positive effects on emotion and increased adherence. Further research should extend these findings and explore their clinical application.