Pain
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Randomized Controlled Trial Clinical Trial
Pre-emptive lumbar epidural anaesthesia reduces postoperative pain and patient-controlled morphine consumption after lower abdominal surgery.
The present study tested the hypothesis that patients receiving epidural bupivacaine before surgery would require less morphine postoperatively and/or report less intense pain than patients receiving epidural bupivacaine after incision but before the end of surgery. Forty-two patients (ASA class I-III) scheduled for lower abdominal surgery were randomly assigned to 1 of 2 groups of equal size and prospectively studied using a double-blind, placebo-controlled crossover design. Epidural catheters were placed in the T12-L1 or L1-L2 interspaces pre-operatively, the position of the catheter was confirmed with 3% chloroprocaine with epinephrine 1:200,000, and sensory testing was carried out until levels had receded to below T12. ⋯ Postoperative analgesia consisted of patient-controlled (PCA) intravenous morphine. Visual analogue pain scores (VAS) (at rest and after standardized mobilization) did not differ significantly between the 2 groups but McGill Pain Questionnaire (MPQ) pain ratings were significantly lower in group 1 at the 24 and 72 h assessments. Group 1 used significantly less morphine than did group 2 between 12 and 24 h after surgery.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
Reduction of temporalis exteroceptive suppression by peripheral electrical stimulation in migraine and tension-type headaches.
Inhibition of the second exteroceptive suppression of temporalis muscle activity (ES2) produced by a preceding electrical stimulus applied at the index was studied in patients suffering from migraine without aura (MO), chronic (CTH) or episodic (ETH) tension-type headache. Each patient group comprised of 12 subjects was compared to a group of healthy controls. Mean duration of unconditioned ES2, measured on 10 averaged rectified responses after labial stimulation at a 0.1 Hz frequency, was reduced in CTH only. ⋯ Among 9 ETH patients with normal (> or = 32 msec) unconditioned ES2, 5 had total disappearance of ES2 after a 20 mA index stimulation. These results demonstrate that peripheral conditioning at 20 mA increases the diagnostic sensitivity of ES2 studies. They suggest that the changes observed in tension-type headache are due to hyperexcitability of the reticular nuclei which inhibit the medullary inhibitory interneurons mediating ES2.
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Previous studies by our laboratory established a rat model of neuropathic pain which displayed long-lasting heat hyperalgesia and mechanical allodynia that are sympathetically maintained. The present study was undertaken to extend our earlier findings by examining additional behavioral signs of ongoing pain and cold allodynia in our animal model and testing their sympathetic dependency. Neuropathic surgery was done by tightly ligating the L5 and L6 segmental spinal nerves of rats unilaterally. ⋯ These behaviors were reduced markedly after surgical lumbar sympathectomy. The results of the present study, together with the previous study, suggest that our animal model exhibits neuropathic pain behaviors including ongoing pain, heat hyperalgesia, mechanical allodynia and cold allodynia. Since all of these behavioral signs are sympathetically maintained, our model represents a model for sympathetically maintained pain.
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Hyperalgesia and allodynia in 4 cancer patients treated with morphine disappeared after discontinuing or substituting morphine with other opioid agonists. The first case describes a young female who developed hyperalgesia and myoclonus during intravenous morphine infusion. The hyperalgesia and myoclonus disappeared when the morphine administration was discontinued and she felt comfortable on small and sporadic oral doses of methadone. ⋯ The fourth case describes a boy developing hyperalgesia after high doses of oral and intramuscular morphine. The hyperalgesia disappeared after discontinuing morphine administration but withdrawal symptoms developed due to too small doses of methadone. Possible mechanisms of morphine-induced hyperalgesia are discussed.
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Case Reports Comparative Study Clinical Trial
Altered pain and temperature perception following cingulotomy and capsulotomy in a patient with schizoaffective disorder.
Recent studies have renewed interest in the role of limbic structures, such as the cingulate cortex, in nociception. To investigate the involvement of the limbic system in pain and temperature perception further, we have quantified ratings of innocuous and noxious thermal stimuli in a patient with schizoaffective disorder before and after 2 surgical procedures. Psychophysical tests were conducted at a control session prior to surgery. ⋯ These altered ratings of noxious heat and cold stimuli were reflected on both a pain intensity and pain affect (unpleasantness) scale. In summary, these data suggest that cingulotomy and capsulotomy disinhibited the patient's noxious heat and cold appreciation. These findings provide support for a role of the cingulate cortex and frontal cortical regions in the perception of innocuous and noxious thermal stimuli and suggest that under normal conditions, these areas may act to suppress the subjective intensity of noxious heat and cold.