Pain
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Clinical Trial
A blinded pilot study investigating the use of diagnostic ultrasound for detecting active myofascial trigger points.
Myofascial trigger points (MFTPs) have been cited by numerous authors as the cause of local and referred pain which arises from muscle and its surrounding fascia. At present there is no reliable objective test which is capable of determining their presence. ⋯ Eleven subjects with clinically identified, unilateral, active MFTPs were examined with diagnostic ultrasound at the site of the trigger point as well as the asymptomatic, contralateral side. The analysis of the results of this pilot study found no correlation between the clinical identification of active MFTPs and diagnostic ultrasound.
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Central sensitization refers to enhanced excitability of dorsal horn neurons and is characterized by increased spontaneous activity, enlarged receptive field (RF) areas, and an increase in responses evoked by large and small caliber primary afferent fibers. Sensitization of dorsal horn neurons often occurs following tissue injury and inflammation and is believed to contribute to hyperalgesia. Windup refers to the progressive increase in the magnitude of C-fiber evoked responses of dorsal horn neurons produced by repetitive activation of C-fibers. ⋯ Enhanced responsivity to C-fiber input following windup produced by stimulation inside the RF at a frequency of 0.5 Hz could be maintained for approximately 100 s by stimuli delivered at 0.1 Hz, a frequency that itself cannot produce windup. It is concluded that neuronal events leading to windup also produce some of the classical characteristics of central sensitization including expansion of RFs and enhanced responses to C- but not A-fiber stimulation. Thus, windup may be a useful tool to study mechanisms underlying certain characteristics of central sensitization related to C-fiber activity.
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Epidural and intrathecal techniques are well established techniques in cancer pain. However, several questions remain unresolved. The several problems of long-term spinal opioid treatment in advance cancer patients were reviewed. ⋯ Different ranges of technical complication rates have been reported in the literature, most of them being associated with epidural catheters. Subcutaneous tunneling and fixation of the catheter, bacterial filters, minimum changes of tubings, careful exit site care weekly, site protection and monitoring of any sign of infection to prevent infection, and training for family under supervision, are recommended. Areas for additional research include the use of spinal adjuvants, the ideal spinal morphine-bupivacaine ratio. methods to improve spinal opioid responsiveness and long-term catheter management with appropriate home care programs.