Current review of pain
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Referred pain, that is, pain perceived in an area other than that in which the noxious stimulation takes place, is very frequent in the clinical setting. There are various forms of referred muscle pain from viscera and from somatic structures. Examples of the latter are referred pain from one muscle to another muscle (as in myofascial pain syndromes) and referred pain from joints (as in osteoarthritis of the knee). ⋯ Referred muscle pain from viscera with hyperalgesia is not completely understood; it is hypothesized that it is due to both central (sensitization process) and peripheral (intervention of reflex arcs) mechanisms. Referred muscle pain from other muscles or from joints is not easily explained by the mechanism of "central convergence" in its original form, because in dorsal horn neurons there is little convergence from deep tissues. It has been proposed that convergent connections from deep tissues to dorsal horn neurons are not present from the beginning but are opened by nociceptive input from skeletal muscle, and referral to myotomes outside the lesion is due to a spread of central sensitization to adjacent spinal segments.
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Tremendous progress has been made in the understanding of neural pathways and tissues involved in back pain, and new treatment techniques for back pain have evolved. This article focuses on a technique called epidural neuroplasty (lysis of epidural adhesions). Originally performed as a single-catheter technique using the caudal approach, this technique now features a number of variations. These variations include emphasis on anterior placement of the catheter tip, use of a transforaminal approach, and use of one or two catheters.
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Current review of pain · Jan 1999
Subarachnoid Techniques for Cancer Pain Therapy: When, Why, and How?
For cancer patients who obtain inadequate pain relief with conservative treatment, there is a growing list of effective options for subarachnoid therapy. Morphine and bupivacaine have been the most frequently used drugs for intrathecal infusion, and their use has consistently yielded good results. ⋯ In addition to new drug options, there are various catheter delivery systems from which to choose. In reviewing the literature and experience to date with these various medications and delivery systems, we hope to better aid the clinician in tailoring the best treatment for each patient.
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Current review of pain · Jan 1999
Spinal Cord Stimulation: Indications, Mechanism of Action, and Efficacy.
Unrelieved pain is costly to the economic fabric of our society; its direct costs to patients and their families is staggering. Spinal cord stimulation for the treatment of chronic pain is cost-effective when used in the context of a pain treatment continuum. Many theories on the mechanism of action of spinal cord stimulation have been suggested, including activation of gate control mechanisms, conductance blockade of the spinothalamic tracts, activation of supraspinal mechanisms, blockade of supraspinal sympathetic mechanisms, and activation or release of putative neuromodulators. Whatever theory or theories of mechanism are correct, spinal cord stimulation has efficacy in the treatment of failed back surgery syndrome, complex regional pain syndromes, intractable pain due to peripheral vascular disease, and intractable pain due to angina.
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Current review of pain · Jan 1999
Direct Evidence of Nociceptive Input to Human Anterior Cingulate Gyrus and Parasylvian Cortex.
Many lines of evidence implicate the anterior cingulate cortex (ACC, Brodmann's area 24) and parasylvian cortex in pain perception. Clinical studies demonstrate alterations in pain and temperature sensation after lesions of these structures. Imaging studies reveal increased blood flow in ACC and parasylvian cortex, both ipsilateral and contralateral to painful stimuli. ⋯ However, these studies incorporate multiple assumptions and therefore do not establish the presence of nociceptive inputs to ACC and parasylvian cortex. We review our recent reports of intracranial potentials evoked by painful stimuli. These studies provide direct evidence of nociceptive inputs to the human ACC and parasylvian cortex.