Pain
-
Randomized Controlled Trial Clinical Trial
Involvement of presurgical pain in preemptive analgesia for orthopedic surgery: a randomized double blind study.
Preemptive analgesia (PA) is effective in animal models but its clinical effectiveness remains controversial. We examined the effect of preexisting pain on PA. Subjects were recruited from patients needing orthopedic surgery. ⋯ PA was effective when presurgical pain was absent, but ineffective when presurgical pain was present. We propose that central sensitization is already established by presurgical pain, and preserved until the termination of surgery. The ineffectiveness of PA did not depend on whether the pain was acute (fracture surgery) or chronic (arthritic surgery).
-
Clinical Trial
Motor cortex stimulation for chronic neuropathic pain: a preliminary study of 10 cases.
There is growing evidence to support the use of motor cortex stimulation (MCS) in the management of patients with chronic neuropathic pain. A prospective audit of ten patients using a modified staged technique for motor cortex implantation provides further evidence for the analgesic effectiveness of this technique. ⋯ We conclude that motor cortex stimulation is an effective analgesic intervention in some patients with chronic neuropathic pain, but it is difficult if not impossible to predict those patients who may respond to treatment prior to implantation. Randomised controlled trials are now urgently needed to test the effectiveness of motor cortex stimulation under double-blind conditions.
-
Several lines of evidence suggest that secondary hyperalgesia to punctate mechanical stimuli arises from central sensitization to the input from primary afferent nociceptors. Conventional C-fiber nociceptors respond to heat stimuli and yet heat hyperalgesia is absent in the region of secondary hyperalgesia. This evidence suggests that the central sensitization to nociceptor input does not involve heat sensitive nociceptors. ⋯ However, touch threshold and pain to pinching stimuli were not significantly altered. The intradermal capsaicin injection led to the development of a similar degree of secondary hyperalgesia at both the vehicle and capsaicin treatment areas. These results indicate that capsaicin insensitive nociceptive afferents play a dominant role not only in normal mechanical pain but also in secondary hyperalgesia to noxious mechanical stimuli.
-
Irritable bowel syndrome (IBS) and fibromyalgia (FM) are considered chronic syndromes of altered visceral and somatic perception, respectively. Because there is a significant overlap of IBS and FM, shared pathophysiological mechanisms have been suggested. Although visceral perception has been well studied in IBS, somatic perception has not. ⋯ Both hypervigilance and somatic hypoalgesia contribute to the altered somatic perception in IBS patients. Co-morbidity with FM results in somatic hyperalgesia in IBS patients.
-
Cognitions and beliefs appear important in predicting adjustment to chronic pain. The current study examines how cognitions and beliefs are related to psychosocial functioning. One hundred and sixty-three chronic pain out-patients were assessed. ⋯ After controlling for demographics, employment status and pain severity, pain beliefs and cognitions accounted for a significant amount of the variance in general activity, pain interference, and affective distress. Negative cognitions, particularly negative self-statements, were more predictive of outcome than pain beliefs. Although these data are correlational, they provide additional support for a biopsychosocial model of adjustment to chronic pain.