Pain
-
Randomized Controlled Trial Multicenter Study Clinical Trial
Oral transmucosal fentanyl citrate (OTFC) for the treatment of breakthrough pain in cancer patients: a controlled dose titration study.
Oral transmucosal fentanyl citrate (OTFC) is a novel opioid formulation in which the potent synthetic mu-agonist fentanyl is embedded in a sweetened matrix that is dissolved in the mouth. It is undergoing investigation as a treatment for cancer-related breakthrough pain, a prevalent phenomenon defined as a transitory flare of moderate to severe pain that interrupts otherwise controlled persistent pain. There have been no controlled trials of other treatments for this condition. ⋯ OTFC appears to be a safe and effective therapy for breakthrough pain, and dose titration can usually identify a unit dose capable of providing adequate analgesia. If the lack of a relationship between the effective OTFC dose and fixed schedule opioid regimen is confirmed, dose titration may be needed in the clinical use of this formulation. Further investigation of OTFC as a specific treatment for breakthrough pain is warranted.
-
Randomized Controlled Trial Clinical Trial
Spatial and temporal summation of sensory and affective dimensions of deep somatic pain.
There is considerable evidence in support of differential information processing of the sensory-discriminative and motivational-affective meanings of pain. The purpose of this work was to examine whether temporal (acute, tonic, persistent) and spatial (local, regional, widespread) aspects of deep somatic pain influence the sensory and affective dimensions of pain. Acute pain consisted of a short bout of pain, lasting about 100 s. ⋯ Affective scores showed the most significant increases from acute to tonic pain, particularly with greater spatial involvement. The significant increases in sensory scores observed when contrasting persistent facial pain alone and in combination with widespread musculoskeletal pain was attributed to the broader body experience. Because the perceptual correlates of tonic and matched persistent (chronic) pain states were similar, we concluded that it does not require months for the development of the sensory and affective meaning of persistent pain as assumed.
-
Case Reports
A case of reflex sympathetic dystrophy (complex regional pain syndrome, type I) resolved by cerebral contusion.
We present a case of refractory reflex sympathetic dystrophy (RSD) (complex regional pain syndrome, type I) whose symptoms (ongoing pain, allodynia, hyperhydrosis and temperature abnormalities) were resolved after the patient suffered a traumatic cerebral contusion in the left temporal lobe, which caused no neurological deficit. This case suggests that symptoms of some RSD patients may largely sustained by a complex network involving the brain.
-
The L5 spinal nerve ligation model of neuropathic pain in rats has been proposed as a model for sympathetically maintained pain (SMP) based on the effects of surgical or chemical sympathectomy on nerve injury induced behavior. In an attempt to confirm that the lesion produces an animal model of SMP, surgical sympathectomies were independently conducted in two different laboratories (Johns Hopkins and University Kiel) using male Sprague-Dawley (n = 30) or Wistar rats (n = 14). The L5 spinal nerve was ligated or cut and ligated. ⋯ Experiments in Wistar and Sprague-Dawley rats yielded the same results. Potential reasons for the discrepancies between the present study and earlier reports are discussed. These results indicate that an L5 spinal nerve injury rat model is not a reliable model for SMP.
-
Recently, Cervero and Laird (NeuroReport, 7 (1996) 526-528; Pain, 68 (1996) 13-23) proposed a new pathophysiological mechanism of dynamic mechanical allodynia in skin. Using the capsaicin pain model in humans, they showed that light mechanical stimulation within an area of secondary mechanical allodynia induces vasodilatation measured by laser-Doppler flowmetry. They suggested that the low-threshold A beta-mechanoreceptive fibres depolarize the central terminals of nociceptive primary afferent neurons via interneurons. ⋯ In conclusion, electrical stimulation of A beta-fibres in allodynic skin does not induce antidromic vasodilatation. Consequently, interaction of A beta-mechanoreceptive fibres and nociceptive C-fibres at a presynaptic level is unlikely to produce antidromically conducted impulses and therefore cannot explain the pathophysiology of mechanical allodynia. Alternatively, it is much more likely that under pathophysiological conditions, activity in A beta-fibres may activate nociceptive second-order neurons, i.e. in the spinal cord.