Pain physician
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Opioids are broad-spectrum analgesics with potent pain-relieving qualities but also with potential adverse effects related to both short-term and long-term therapy. Researchers have attempted to alter existing opioid analgesics, utilize different routes/formulations, or combine opioid analgesics with other compounds in efforts to improve analgesia while minimizing adverse effects. Exogenous opioids, administered in efforts to achieve analgesia, work by mimicking the actions of endogenous opioids. ⋯ This notion has been supported by the observation that the quaternary compound morphine methyliodide, which does not as readily cross the bloodbrain barrier and enter the CNS, produced antinociception following intradermal administration into the hindpaw, but not when the same dose was administered systemically (subcutaneously at a distant site). With a growing appreciation of peripheral endogenous opioids, peripheral endogenous opioid receptors, and peripheral endogenous opioid analgesic systems, investigators began growing hopeful that it may be possible to achieve adequate analgesics while avoiding unwanted central untoward adverse effects (e.g. respiratory depression, somnolence, addiction). Peripherally-acting opioids, which capitalize on peripheral endogenous opioid analgesic systems, may be one potential future strategy which may be utilized in efforts to achieve potent analgesia with minimal side effects.
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It has been appreciated for some time now that humans react differently to opioids. A specific opioid such as morphine sulfate may have specific analgesic effects for certain patients with postherpetic neuralgia whereas in other patients with postherpetic neuralgia, it may provide quite different analgesic qualities. Also, in any one individual patient a particular opioid may provide better analgesia than other opioids. ⋯ In the future, knowledge gained from databases on knockout rodents, pharmacogenetics, and gene polymorphisms may impact on the ability of clinicians to predict patient responses to doses of specific opioids in efforts to individualize optimal opioid analgesic therapy. It is conceivable that eventually information of this type may translate into improved patient care. In the future, armed with data of this type, clinicians may become quite adept at tailoring appropriate opioid therapy as well as optimal opioid rotation strategies.
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Chronic pelvic pain can present in various pain syndromes. In particular, interventional procedure plays an important diagnostic and therapeutic role in 3 types of pelvic pain syndromes: pudendal neuralgia, piriformis syndrome, and "border nerve" syndrome (ilioinguinal, iliohypogastric, and genitofemoral nerve neuropathy). The objective of this review is to discuss the ultrasound-guided approach of the interventional procedures commonly used for these 3 specific chronic pelvic pain syndromes. ⋯ The ultrasound machine is portable and is more readily available to the pain specialist. It prevents patients and healthcare professionals from the exposure to radiation during the procedure. Because it allows the visualization of a wide variety of tissues, it potentially improves the accuracy of the needle placement, as exemplified by various interventional procedures in the pelvic regions aforementioned.
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Comparative Study
Influence of psychological variables on the diagnosis of facet joint involvement in chronic spinal pain.
Facet or zygapophysial joint pain is one of the common conditions responsible for chronic spinal pain. Controlled diagnostic blocks are considered the only means of reliable diagnosis of facet joint pain, due to the inability of physical examination, clinical symptoms, radiologic evaluation, and nerve conduction studies to provide a reliable diagnosis. The prevalence of facet joint pain has been established to be 15% to 45% of patients with low back pain, 39% to 67% of patients with neck pain, and 34% to 48% of patients with thoracic pain. However, using only a single block, false-positive rates of 27% to 63% in the cervical spine, 42% to 58% in the thoracic spine, and 17% to 50% in the lumbar spine have been reported. While there are multiple reasons for false-positive results, psychological variables may also contribute to false-positive results. A lack of influence of psychological factors on the validity of controlled diagnostic local anesthetic blocks of lumbar facet joints has been demonstrated. However, no such studies have been performed in the thoracic or cervical spine. ⋯ This study demonstrated that, based on patient psychopathology, there were no significant differences among the patients either in terms of prevalence or false-positive rates in the lumbar and thoracic regions. A higher prevalence and lower false-positive rates in the cervical region were established in patients with major depression.