Pain
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Pulse radiofrequency has been recently described as a technique to apply a relatively high voltage near a nerve but without the usual effects of a rise in temperature or subsequent nerve injury. In this set of case reports, the effect of pulsed radiofrequency (PRF) is described in patients with neuropathic pain syndromes which have been poorly controlled with other oral and invasive treatments. Whilst anecdotal, the results have been remarkable and should encourage further research into this technique. Observations from the basic science tend to support the concept that PRF may induce some sort of long-term depression in the spinal cord.
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Clinical Trial
Pain-related fear is more disabling than pain itself: evidence on the role of pain-related fear in chronic back pain disability.
There is growing evidence for the idea that in back pain patients, pain-related fear (fear of pain/physical activity/(re)injury) may be more disabling than pain itself. A number of questionnaires have been developed to quantify pain-related fears, including the Fear-Avoidance Beliefs Questionnaire (FABQ), the Tampa Scale for Kinesiophobia (TSK), and the Pain Anxiety Symptoms Scale (PASS). A total of 104 patients, presenting to a rehabilitation center or a comprehensive pain clinic with chronic low back pain were studied in three independent studies aimed at (1) replicating that pain-related fear is more disabling than pain itself (2) investigating the association between pain-related fear and poor behavioral performance and (3) investigating whether pain-related fear measures are better predictors of disability and behavioral performance than measures of general negative affect or general negative pain beliefs (e.g. pain catastrophizing). ⋯ Even when controlling for sociodemographics, multiple regression analyses revealed that the subscales of the FABQ and the TSK were superior in predicting self-reported disability and poor behavioral performance. The PASS appeared more strongly associated with pain catastrophizing and negative affect, and was less predictive of pain disability and behavioral performance. Implications for chronic back pain assessment, prevention and treatment are discussed.
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Clinical Trial
Electrophysiological testing of the trigeminofacial system: aid in the diagnosis of atypical facial pain.
The aim of this study was to evaluate the yield of objective electrophysiological testing of the trigeminofacial system in atypical facial pain (AFP). In addition to the clinical neurological examination, two brainstem reflexes covering both the peripheral parts and the central connections of the trigeminal and the facial nerves, the blink and jaw reflexes (BR and JR), were recorded in 17 AFP patients. The control group consisted of 18 healthy volunteers with no history of facial pain or chronic headache. ⋯ Additionally, one patient had abnormal BAEP and EEG recordings. On the group level, the AFP patients had significantly higher thresholds of the tactile R1 component of the BR than the control subjects. Electrophysiological testing may offer a valuable tool for both the clinical evaluation, and the scientific study of AFP.
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A single injection of streptozocin (50 mg/kg, i.p.) led to the development of static and dynamic allodynia in the rat. The two responses were detected, respectively, by application of pressure using von Frey hairs or lightly stroking the hind paw with a cotton bud. Static allodynia was present in the majority of the animals within 10 days following streptozocin. ⋯ In contrast, administration of similar doses of gabapentin into the hind paw failed to block these responses. It is suggested that in this model of neuropathic pain dynamic allodynia is mediated by A beta-fibres and the static type involves small diameter nociceptive fibres. These data suggest that gabapentin and pregabalin possess a superior antiallodynic profile than morphine and amitriptyline, and may represent a novel class of therapeutic agents for the treatment of neuropathic pain.
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of 50, 100 and 200 mg of intra-articular pethidine during knee joint surgery, a controlled study with evidence for local demethylation to norpethidine.
Pethidine (meperidine) is a compound with both local anaesthetic and opioid agonist properties. We have in a recent study demonstrated that pethidine could be an interesting alternative to prilocaine in arthroscopy with local anaesthetic technique. Therefore, we investigated, in a controlled randomized double-blind study, the effect of three doses of pethidine compared with a standard local anaesthetic, in patients subjected to arthroscopic knee joint surgery. ⋯ This site of drug oxidation has not earlier been demonstrated neither in vitro nor in vivo. The results suggest that pethidine given i.a. in the dose range of 50 to 200 mg results in analgesia due to both peripheral and central mechanisms. The significant systemic uptake of pethidine can cause unwanted side-effects.