Pain
-
Surgery and trauma are recognised as important causes of chronic pain, although their overall contribution has not been systematically studied. This paper reports on the contribution of surgery and trauma to chronic pain among 5130 patients attending 10 outpatient clinics located throughout North Britain. Surgery contributed to pain in 22.5% of patients, and was particularly associated with the development of pain in the abdomen and with anal, perineal and genital pain. ⋯ These findings indicate that it can be unhelpful for pain classification systems to combine surgery and trauma in a single category. The results also point to areas for potentially fruitful research into the aetiology of chronic pain. In particular, studies are needed to identify the operative procedures associated with the development of pain so that preventive measures can be implemented.
-
Gabapentin (GP) has been shown to have antihyperalgesic properties and the site of drug action is reported to be the central nervous system. The goal of the present study was to determine whether GP also has a peripheral site of action. ⋯ The antihyperalgesic effect of GP (1) was not due to a systemic effect since animals injected with 600 microg GP in one hindpaw and 2% formalin into the contralateral hindpaw developed nociceptive behaviors which were no different than those seen in animals injected with formalin alone; (2) was not due to a local anesthetic effect since needle sticks within the drug-injected region evoked paw withdrawal behavior which was not different from pre-drug levels; (3) was blocked by 20 microl D-serine but not by L-serine. Although the mechanism of action of GP has yet to be elucidated, these results indicate that GP has a peripheral site of action and thus may offer a novel therapeutic agent for topical or local treatment of pain of peripheral origin.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Peripheral morphine analgesia in dental surgery.
The recent identification of opioid receptors on peripheral nerve endings of primary afferent neurons and the expression of their mRNA in dorsal root ganglia support earlier experimental data about peripheral analgesic effects of locally applied opioids. These effects are most prominent under localized inflammatory conditions. The clinical use of such peripheral analgesic effects of opioids was soon investigated in numerous controlled clinical trials. ⋯ No serious side effects were reported. Our results show that 1 mg of morphine added to a local anesthetic for dental surgery results in significant improvement of postoperative analgesia. Since the majority of dental surgeries is accompanied with an inflammatory reaction, supplemental morphine may be of benefit for the relief of postoperative dental pain.
-
Comparative Study Clinical Trial
Gender differences in pain perception and patterns of cerebral activation during noxious heat stimulation in humans.
The purpose of the present study was to determine whether gender differences exist in the forebrain cerebral activation patterns of the brain during pain perception. Accordingly, positron emission tomography (PET) with intravenous injection of H2(15)O was used to detect increases in regional cerebral blood flow (rCBF) in normal right-handed male and female subjects as they discriminated differences in the intensity of innocuous and noxious heat stimuli applied to the left forearm. Each subject was instructed in magnitude estimation based on a scale for which 0 indicated 'no heat sensation'; 7, 'just barely painful' and 10, 'just barely tolerable'. ⋯ However, females had significantly greater activation of the contralateral prefrontal cortex when compared to the males by direct image subtraction. Volume of interest comparison (t-statistic) also suggested greater activation of the contralateral insula and thalamus in the females (P < 0.05). These pain-related differences in brain activation may be attributed to gender, perceived pain intensity, or to both factors.
-
The purpose of this study was to examine the utility of the pain map as a pain assessment tool in frail nursing home residents. The study was conducted in two phases. In Phase 1, nursing home staff's knowledge of the locations of resident pain complaints was examined. ⋯ Pain extensity also demonstrated modest predictive validity with self-rated health, but not with depression or functional impairment. The advantage of knowing where residents hurt is that this allows staff to target their assessment and thus determine the functional implications of residents' pain. It appears that pain maps add a useful dimension to pain assessment in residents of long term care facilities.