European journal of pain : EJP
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Persistent postsurgical pain has been reported following cosmetic breast augmentation, but little is known about the underlying mechanisms. ⋯ Sensory changes and persistent pain are common following cosmetic breast augmentation and may have a negative impact on daily activities and satisfaction after surgery. Findings suggest that neuropathic pain should be considered in these patients. Preoperative information about the risk of developing sensory changes and chronic pain after breast augmentation is important.
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Insensitivity to pain is a rare disorder that is commonly associated with Hereditary Sensory and Autonomic Neuropathies (HSAN I-V) resulting often in autonomic dysfunction and premature death. Very few individuals have been reported with pain insensitivity lacking such autonomic neuropathies. We performed genetic, neurologic, psychological, and psychophysical evaluations in such an individual (OMIM 243000) and her first degree relatives. ⋯ Congenital insensitivity to pain in our IC was associated with two novel SCN9A mutations which most likely resulted in a Nav1.7 channelopathy. However, in contrast to individuals with other SCN9A mutations, the observed pain insensitivity was relative and not absolute, which may be consistent with hypomorphic effects of one or both mutations. The ability to sense at least some danger signals may be advantageous and ameliorate the otherwise increased morbidity and mortality of some individuals with congenital insensitivity to pain.
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Motor cortex stimulation (MCS) has been used to treat patients with neuropathic pain resistant to other therapeutic approaches; however, the mechanisms of pain control by MCS are still not clearly understood. We have demonstrated that MCS increases the nociceptive threshold of naive conscious rats, with opioid participation. In the present study, the effect of transdural MCS on neuropathic pain in rats subjected to chronic constriction injury of the sciatic nerve was investigated. ⋯ Zif268 results were similar to those obtained for Fos, although no changes were observed for Zif268 in the anterior cingulate cortex and the central amygdaloid nucleus after MCS. The present findings suggest that MCS reverts neuropathic pain phenomena in rats, mimicking the effect observed in humans, through activation of the limbic and descending pain inhibitory systems. Further investigation of the mechanisms involved in this effect may contribute to the improvement of the clinical treatment of persistent pain.
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This study is part of a research program to reach consensus on an international cancer pain classification system. A confirmative and explorative approach was applied to investigate which of the variables identified in the literature, by experts and patients that are associated with pain. ⋯ Breakthrough pain and psychological distress were confirmed as key variables of a future classification system. Candidate variables were: sleep, opioid dose, pain mechanism, use of non-opioids, pain localisation, cancer diagnosis, location of metastases, and addiction.
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Clinical Trial
Potentiation of buprenorphine antinociception with ultra-low dose naltrexone in healthy subjects.
Previous reports have demonstrated greater antinociception following administration of a buprenorphine/naloxone combination compared to buprenorphine alone among healthy volunteers. The aim of the current investigation was to determine whether buprenorphine antinociception could be enhanced with the addition of ultra-low dose naltrexone, using a range of dose ratios. A repeated-measures, double-blind, cross-over trial was undertaken with 10 healthy participants. ⋯ Minimal respiratory depression and few adverse events were observed in all conditions. These findings suggest that, as previously described with naloxone, the addition of ultra-low dose naltrexone can enhance the antinociceptive effect of buprenorphine in humans. This potentiation is dose-ratio dependent and occurs without a concomitant increase in adverse effects.