Pain
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Patients with pain may be at increased risk of developing a first episode of depressive or anxiety disorder. Insight into possible associations between specific pain characteristics and such a development could help clinicians to improve prevention and treatment strategies. The objectives of this study were to examine the impact of pain symptomatology on depression and anxiety onset and to determine whether these associations are independent of subthreshold depressive and anxiety symptoms. ⋯ By contrast, there was no association with duration of pain symptoms (HR=1.47; P=.12). Independent of subthreshold affective symptoms, only joint pain and increasing number of pain locations were still significantly associated with depression and anxiety onset. Clinicians should be aware that regardless of affective symptoms, pain, particularly at multiple locations, is a risk indicator for developing depressive and anxiety disorders.
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Randomized Controlled Trial Comparative Study
Comparison of postoperative pain in the first and second knee in staged bilateral total knee arthroplasty: clinical evidence of enhanced pain sensitivity following surgical injury.
Staged bilateral total knee arthroplasty (TKA) may provide an ideal clinical model for the study of central sensitization. In staged TKA, hyperalgesia may be induced as a result of repeated surgical injury possibly via central sensitization, which can decrease functional outcomes. Therefore, we hypothesized that in staged bilateral TKA, patients would have greater pain in the second operated knee than in the first. ⋯ Patients undergoing staged bilateral TKA experience greater postoperative pain in the second operated knee than the first. This suggests extension of hyperalgesia beyond the initially injured site to remote regions after surgical injury, in which central sensitization may be involved. Therapeutic approaches to reduce such hyperalgesia induced in the course of staged operations are required.
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Randomized Controlled Trial
A Pilot Trial of Intravenous Pamidronate for Chronic Low Back Pain.
Intravenous (i.v.) bisphosphonates relieve pain in conditions such as Paget's disease of bone, metastatic bone disease, and multiple myeloma. Based on positive findings from a prior case series, we conducted a randomized placebo-controlled study to assess the analgesic effect of i.v. pamidronate in subjects with chronic low back pain (CLBP) and evidence of degenerative disease of the spine. Four groups of 11 subjects (7 active, 4 placebo) were enrolled at escalating dose levels of 30, 60, 90, and 180 mg pamidronate (the latter administered as two 90 mg infusions). ⋯ Least squares mean changes in daily average pain score were -1.39 (SE=0.43) for placebo, and -1.53 (0.71), -1.26 (0.81), -1.42 (0.65), and -4.13 (0.65) for pamidronate 30, 60, 90, and 180 mg, respectively (P=0.012 for pamidronate 180 mg vs placebo). The proportion of responders, changes in worst pain, and pain interference with daily function were also significantly improved for pamidronate 180 mg compared with placebo. In conclusion, i.v. pamidronate, administered as two 90 mg infusions, decreased pain intensity for 6 months in subjects with CLBP.
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The brain mechanisms by which sensory cues become transformed into expectations of impending events are a critical component of cognitive tuning of sensory processing. However, distinctions among the afferent processing of cue-related activity itself versus those mechanisms supporting the contextual meaning imparted to the cue remain limited. Do sensory cues with equal meaning engage similar patterns of brain activations even if they are delivered in separate modalities? To address this question, we used functional magnetic resonance imaging of an expectation paradigm in which cues were delivered with visual or innocuous thermal stimuli. ⋯ This activation may reflect processes directing spatial attention to the stimulated body region in order to more accurately evaluate the relatively weak, low pain stimulus. Taken together, these findings indicate that cues arising from different sensory modalities ultimately engage common brain mechanisms that reflect the meaning of the cue. This meaning-related activity is presumably critical for preparing sensory systems to optimally process afferent information.