Pain
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Peripheral sensory ganglia contain somata of afferent fibres conveying somatosensory inputs to the central nervous system. Growing evidence suggests that the somatic/perisomatic region of sensory neurons can influence peripheral sensory transmission. Control of resting membrane potential (Erest) is an important mechanism regulating excitability, but surprisingly little is known about how Erest is regulated in sensory neuron somata or how changes in somatic/perisomatic Erest affect peripheral sensory transmission. ⋯ Acute focal application of M or KATP channel enhancers or a hyperpolarization-activated cyclic nucleotide-gated channel blocker to L5 DRG in vivo significantly alleviated pain induced by hind paw injection of bradykinin. Finally, we show with computational modelling how somatic/perisomatic hyperpolarization, in concert with the low-pass filtering properties of the t-junction within the DRG, can interfere with action potential propagation. Our study deciphers a complement of ion channels that sets the somatic Erest of nociceptive neurons and provides strong evidence for a robust filtering role of the somatic and perisomatic compartments of peripheral nociceptive neuron.
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Randomized Controlled Trial Multicenter Study
Spinal cord stimulation in patients with painful diabetic neuropathy: a multicentre randomised clinical trial.
Painful diabetic neuropathy (PDN) is a peripheral neuropathic pain condition that is often difficult to relieve. Spinal cord stimulation (SCS) is a proven effective therapy for various types of mixed neuropathic conditions, yet effectiveness of SCS treatment for PDN is not well established. To our knowledge, ours is the first multicentre randomized controlled trial investigating the effectiveness of SCS in patients with PDN. ⋯ After 6 months of treatment, the average VAS score was significantly reduced to 31 in the SCS group (P<.001) and remained 67 (P=.97) in the control group. The SF-MPQ and EuroQoL 5D questionnaires also showed that patients in the SCS group, unlike those in the control group, experienced reduced pain and improved health and quality of life after 6 months of treatment. In patients with refractory painful diabetic neuropathy, spinal cord stimulation therapy significantly reduced pain and improved quality of life.
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Chronic pain after laparoscopic cholecystectomy is related to postoperative pain during the first postoperative week, but it is unknown which components of the early pain response is important. In this prospective study, 100 consecutive patients were examined preoperatively, 1 week postoperatively, and 3, 6, and 12 months postoperatively for pain, psychological factors, and signs of hypersensitivity. Overall pain, incisional pain (somatic pain component), deep abdominal pain (visceral pain component), and shoulder pain (referred pain component) were registered on a 100-mm visual analogue scale during the first postoperative week. ⋯ There were no consistent signs of hypersensitivity in the referred pain area either pre- or postoperatively. There were no significant associations to any other variables examined. The risk of chronic pain after laparoscopic cholecystectomy is relatively low, but significantly related to the visceral pain response during the first postoperative week.
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The current study aimed to validate the child and parent pain catastrophizing scale in a large chronic pain sample and to identify child pain catastrophizing clinical reference points. Patients and parents (n=697) evaluated at a pediatric pain program completed the Pain Catastrophizing Scale, child (PCS-C) and parent (PCS-P) reports, along with additional measures of psychological functioning. The measure's psychometric properties were examined, as were relations across demographic, pain, and psychological characteristics and pain catastrophizing. ⋯ When comparing PCS-C scores based on child outcomes, significant differences emerged for low, moderate, and high catastrophizing levels. It appears that the influence of parent catastrophizing on outcomes can be explained through its impact on child catastrophizing levels. PCS-C reference points derived from this large sample can aid clinicians in assessment and treatment planning, in turn increasing the utility of the PCS-C for both clinical and research purposes.