Articles: pain.
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This study investigated the quality and magnitude of sensations evoked by electrical tooth pulp stimulation. Detection threshold (the minimum current intensity that evoked a sensation) and pain threshold were determined for tooth pulp stimuli varying in frequency from 5 to 500 Hz. The effect of frequency and intensity of tooth pulp stimulation on the magnitude of sensations was assessed using visual analog scales and verbal descriptor scales. ⋯ These findings suggest that the non-pain sensations evoked in tooth pulp are mediated by a distinct population of afferents that are not involved in the coding of pain. High frequency stimulation that increased the discharge rate of the lowest threshold pulpal afferents resulted in no summation of non-pain sensation and never produced pain. However, high frequency stimulation evoked greater magnitude sensations at higher stimulus currents, indicating that central summation mechanisms were critical for higher threshold afferents signaling more intense non-pain and pain sensations.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of effects of intraoperative and postoperative methadone: acute tolerance to the postoperative dose?
The effects of methadone 10 mg administered in two different clinical contexts, at induction of anaesthesia and following operation, were studied in two groups of patients undergoing elective total hip replacement. The intraoperative group received methadone 10 mg i.v. at induction of anaesthesia as part of a balanced anaesthetic technique. The postoperative group received methadone 10 mg i.v. following operation, extradural bupivacaine being used for the operative period. ⋯ Subsequently, the postoperative group had a significantly greater analgesic requirement which resulted in significantly greater plasma methadone concentrations the following morning. Thus, the administration of methadone following operation appeared to exert less analgesic effect than the same dose given during operation. The reasons for this are discussed.
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All the medical, surgical and engineering personnel in the UK who have used spinal cord stimulation (SCS) in patients, attended a workshop to discuss their results. The major use of SCS has been for multiple sclerosis and intractable pain. ⋯ Further information on long term benefit is needed and the use of SCS in other conditions, such as spinal injury and peripheral vascular disease, is not yet established. SCS cannot be recommended for use outside large centres as x-ray screening, urodynamic and neurophysiological assessment facilities are required as well as biological engineering assistance.