Articles: chronic-pain.
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Chronic-constriction injury (CCI) of the sciatic nerve causes mechanical and heat hyperalgesia and mechanical allodynia in the plantar surface of the hindpaw. The underlying mechanism thought to account for these phenomena include central sensitization induced by peripheral nerve injury, ie, the increase in neuronal activity of spinal dorsal horn neurons. As a marker of neuronal activation of the central nervous system, Fos expression has been used widely to monitor the change in neuronal activity evoked by peripheral input. ⋯ The number of noxious stimulus-evoked Fos-labeled neurons in both the superficial and deep laminae of the dorsal horn in the CCI rats was increased significantly compared with those in sham-operated rats, suggesting an increased excitability of dorsal horn neurons to noxious stimuli. Concurrent EA treatment to the Zusanli point with the pinch stimulus suppressed the increase in the number of Fos-labeled cells in the spinal dorsal horn in the CCI rats. The present results show that EA treatment has antinociceptive effects on both pain behavior and neuronal activation of the spinal dorsal horn neurons in CCI rats.
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According to the fear avoidance model, prolonged disability among patients with chronic nonmalignant pain is due, in part, to an exaggerated fear of pain. At issue in the present study was an attempt to refine the fear-avoidance hypothesis by eliciting estimates of anticipated pain as well as anticipated injury. Along with scores on the Fear Avoidance Beliefs Questionnaire-Work (FABQ-W), a validated measure of fear avoidance, pain and injury expectancies were used as predictors of work disability in a hierarchical regression model. ⋯ After controlling for pain duration, depression, somatization, and current pain severity, pain expectancy alone accounted for 16% of the variance in patients in the chronic group (P < .001) and 33% of the variance in patients in the acute group (P < .001). Both pain and injury expectancies were associated equally with work disability for patients in the acute group (P < .001), but only pain expectancy accounted for variance in the chronic group (P < .001). Fear-avoidance beliefs, in the form of cognitive expectancies, may have as much influence on the duration of disability in patients with acute pain as they do in patients with chronic pain.
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Postlumbar laminectomy syndrome, or pain following operative procedures of the lumbar spine, is increasingly a common entity in modern medicine. Multiple causes proposed for recurrence of pain after lumbar laminectomy are: epidural fibrosis, recurrent disc herniation, instability, and facet joints. Even though the prevalence of persistent low back pain secondary to the involvement of lumbosacral facet joints has been described in controlled studies from 15% to 45%, the prevalence of facet joint mediated pain in postlumbar laminectomy syndrome has not been studied. ⋯ Results showed that the prevalence of facet joint mediated pain in non-surgical patients was 44% compared to 32% in post surgical patients determined by comparative controlled local anesthetic blocks utilizing lidocaine and bupivacaine. This study also showed a false positive rate of 36% in non-surgical group and 24% in post-surgical group. In conclusion, this study shows that facet joint mediated symptomatology in chronic low back pain is prevalent, both in non-surgical as well as post-surgical patients even though prevalence was somewhat higher in the non-surgical group compared to post-surgical group.
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Epidural fibrosis is seen as a common phenomenon among postlumbar laminectomy syndrome patients, contributing to approximately 60% of symptom recurrence. Percutaneous epidural lysis of adhesions has been described as a modality to effectively manage chronic low back pain secondary to epidural fibrosis. Forty-five patients were randomly assigned, with fifteen patients in the control group, or Group I, who were treated with conservative modalities of treatments, including medication, physical therapy, and an exercise program; and, thirty patients in Group II, who were treated with percutaneous epidural adhesiolysis and hypertonic saline neurolysis. ⋯ The study also showed that overall health status improved significantly in the treatment group in all parameters with average pain, physical health, mental health, functional status, psychological status and narcotic intake. Analysis also showed that this is a cost-effective treatment, with cost for 1-year improvement of quality of life at $2693. In conclusion, epidural adhesiolysis with hypertonic saline neurolysis performed on a 1-day basis is an effective modality of treatment in managing chronic low back pain in patients who failed to respond to fluoroscopically directed epidural steroid injections and also were demonstrated not to have facet joint mediated pain.
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The objective of this paper is to examine the outcomes of patients with intractable low-back pain treated with epidural spinal cord stimulation (SCS) utilizing paddle electrodes and a radio frequency (RF) stimulator. A multicenter prospective study was performed to collect data from patients suffering from chronic low-back pain. The study was designed to collect data from 60 patients at four centers and examine their outcomes at, or up to two years post implantation. ⋯ The majority of patients reported that the procedure was worthwhile (92% at six months, 88% at one year). No patient indicated that the procedure was not worthwhile. We conclude that SCS proved beneficial at one year for the treatment of patients with chronic low back and leg pain.