European journal of pain : EJP
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Comparative Study
Effects of pulsed versus conventional radiofrequency current on rabbit dorsal root ganglion morphology.
Lesioning using radiofrequency (RF) current has been increasingly used in clinical practice for the treatment of pain syndromes. Although formation of heat causing "thermocoagulation" of the nervous tissues is thought to be responsible of the clinical outcome, a more recent modality of RF application named pulsed radiofrequency (PRF) delivers the RF current without producing destructive levels of heat. In our study, we compared the effects of conventional RF (CRF) and PRF on rabbit dorsal root ganglion (DRG) morphology, including also control and sham operated groups. ⋯ The myelinated and unmyelinated nerve fibers were of normal morphology in all groups. Our results suggest that PRF application is less destructive of cellular morphology than CRF at clinically used "doses". Before making certain judgements, more experimental and clinical studies should be planned.
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Randomized Controlled Trial Clinical Trial
The causal status of pain catastrophizing: an experimental test with healthy participants.
In the current study we report findings on the effects of experimentally induced catastrophizing about pain on expected pain, experienced pain and escape/avoidance behavior during a cold pressor task in a sample of healthy participants. It was hypothesized that increasing the level of catastrophizing would result in a higher level of expected pain, a higher level of experienced pain, and a shorter duration of ice-water immersion. ⋯ The results demonstrated that despite the successful attempt to induce catastrophizing, this neither significantly affected expected pain, experienced pain, and duration of ice-water immersion, nor were these relations moderated by the pre-experimental level of catastrophizing. Although the level of catastrophizing was successfully manipulated, more similar experiments are necessary in order to give a more definite answer on the possible causal status of pain catastrophizing.
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The aim of this study was to evaluate psychosocial behaviour and differences in health care utilization between subgroups of patients suffering from temporomandibular disorders, using both clinical examination and magnetic resonance imaging (MRI). ⋯ Somatization-specific behaviour is more widespread in patients suffering from exclusively myofascial pain than in patients presenting joint pathology. Inconsistencies in differences of other psychosocial variables between groups of TMD patients seem to be related to differences in group assignment either with or without objective information on joint pathology.
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Comparative Study
Psychiatric comorbidity in medication overuse headache patients with pre-existing headache type of episodic tension-type headache.
Medication overuse headache (MOH) mostly evolves from migraine and episodic tension-type headache (ETTH). Chronic tension-type headache (CTTH) is another headache type that evolves over time from ETTH. It is well known that psychiatric comorbidity is high in MOH patients. ⋯ Psychiatric comorbidity in MOH patients with pre-existing ETTH is common as in those with pre-existing migraine headache and MOH with regard to developing psychiatric disorders should be interpreted as a risk factor in chronic daily headache patients.
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Pressure pain thresholds (PPTs) and event-related potentials (ERPs) elicited by emotional words were analyzed in 12 patients with fibromyalgia (FM) and 12 matched healthy subjects. PPTs were assessed at the middle finger of both hands, before and after the experiment. Overall, FM patients and healthy subjects did not differ in PPT. ⋯ A significant group effect was observed on P200 amplitudes, showing reduced amplitudes in FM patients as compared to healthy controls. Furthermore, unpleasant pain-related compared to neutral words triggered significantly enhanced late positive slow waves in healthy controls, while a comparable effect was not found in FM patients. The ERP and PPT data suggest that FM patients are characterized by an altered cognitive processing of pain-related information and by an abnormal adaptation to mechanical pain stimuli, respectively.