The journal of pain : official journal of the American Pain Society
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Like other types of neuropathic pain, postherpetic neuralgia (PHN) can be resistant to many types of pharmacologic and interventional therapies. Although many analgesic agents have been used for the treatment of other types of neuropathic pain, tricyclic antidepressants, antiepileptic drugs, opioids, and lidocaine patch appear to demonstrate relative analgesic efficacy for the treatment of pain from PHN. There are fewer studies on the use of interventional options for the treatment of pain from PHN. The majority of interventional therapies show equivocal analgesic efficacy although some data indicate that intrathecal methylprednisolone may be effective. Further randomized, controlled trials will be needed to confirm the analgesic efficacy of analgesic and interventional therapies to determine their role in the overall treatment of patients with PHN. ⋯ This article reviews the analgesic options for the treatment of PHN and suggests that tricyclic antidepressants, membrane stabilizers, opioids, and lidocaine patch may demonstrate analgesic efficacy in this group of patients. These data may potentially help clinicians who attempt to provide analgesia in patients with PHN.
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Randomized Controlled Trial
Effects of a selective cyclooxygenase-2 inhibitor on postoperative inflammatory reaction and pain after total knee replacement.
The goal of this study was to evaluate the systemic and peripheral effects of preoperative administration of cyclooxygenase-2 inhibitor on pain and inflammation occurring with total knee replacement (TKR). Patients undergoing elective TKR were prospectively and randomly given oral rofecoxib (25 mg) or placebo (control group) 1 hour before surgery. All patients received an epidural combined with isoflurane anesthesia during the operation and patient-controlled epidural analgesia postoperatively. The outcome measures included pain scores during rest and movement of knee joints and cumulative morphine consumption. Femoral blood and knee joint drainage fluids were examined for leucocyte numbers and concentrations of cytokines (including IL-6, IL-8, IL-10, and TNF-alpha). Periarticular circumferential increments at 48 hours served as an indication of inflammatory edema. Pain scores during rest and knee joint movement on postoperative days 1 and 2 were better in those given rofecoxib than in control subjects, and cumulative morphine consumption for the first 24 hours was significantly reduced. Both groups had higher concentrations of IL-6 and IL-8 in knee drainage fluid compared with serum levels. Rofecoxib significantly decreased regional IL-6 and TNF-alpha level after surgery. Moreover, the incidence of febris and degree of local edema were lower in the rofecoxib group (P < .05), and peripheral IL-6 level significantly correlated with pain score at 48 hours. Preoperative administration of rofecoxib increases patient satisfaction with analgesia, reduces opioid requirement, and decreases both systemic and local anti-inflammation after TKR. ⋯ This randomized, double-blinded trial shows that preoperative administration of rofecoxib can greatly ameliorate the pain occurring with total knee joint replacement surgery and its accompanying reduction of general and local inflammatory reactions.
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The method of pain-evoked potentials has gained considerable acceptance over the last 3 decades regarding its objectivity, repeatability, and quantifiability. The present study explored whether the relationship between pain-evoked potentials and pain psychophysics obtained by contact heat stimuli is similar to those observed for the conventionally used laser stimulation. Evoked potentials (EPs) were recorded in response to contact heat stimuli at different body sites in 24 healthy volunteers. Stimuli at various temperatures were applied to the forearm (43 degrees C, 46 degrees C, 49 degrees C, and 52 degrees C) and leg (46 degrees C and 49 degrees C). The amplitudes of both components (N2 and P2) were strongly associated with the intensity of the applied stimuli and with subjective pain perception. Yet, regression analysis revealed pain perception and not stimulus intensity as the major contributing factor. A significant correlation was found between the forearm and the leg for both psychophysics and EPs amplitude. ⋯ Contact heat can generate readily distinguishable evoked potentials on the scalp, consistent between upper and lower limbs. Although these potentials bear positive correlation with both stimulus intensity and pain magnitude, the latter is the main contributor to the evoked brain response.
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This study aimed to determine if electromyographic (EMG) diagnostic evaluation can predict functional outcome in patients undergoing transforaminal lumbar spine epidural injections. In this retrospective study, functional outcome by Oswestry Disability Index (ODI) and verbal rating scale (VRS) for current pain severity was evaluated in 39 patients undergoing lumbar transforaminal epidural spinal injections (ESI). Subjects with low back pain (mean age, 60 +/- 12.5 years) were evaluated for functional improvement post EMG and ESI. Of 39 patients tested with EMG before injection, 18 patients were positive for radiculopathy and 21 had a normal or negative examination. The patients were followed postinjection on average of 10.8 (SD +/- 3.9) weeks. Pretreatment ODI scores were not significantly different between groups showing positive (72.3 SD +/- 12.7) and negative (65.9 SD +/- 18.6, P > .05) EMG findings. There was significantly greater improvement of ODI for EMG positive radiculopathy (7.11 SD +/- 9.5) compared with negative EMG (3.2 SD +/- 17.4, P < .05). Positive radiculopathy subjects complained of more pain by VRS before ESI than subjects with negative EMG findings, 8.1 SD +/- 1.0 and 7.3 SD +/- 0.8, respectively, which was not significant (P > .05). VRS mean improvement was not significantly different in the positive EMG group (1.8 SD +/- 1.2) compared with a negative EMG (1.2 SD +/- 1.2, P > .05). ⋯ The results appear to show that patients undergoing transforaminal ESI, who have a positive radiculopathy by EMG before injection, will have significant improvement in functional outcome by ODI but not with current pain intensity by VRS. This study suggests the importance and diagnostic value of ordering electromyography studies for lumbar radiculopathy evaluation, which may lead to prediction of outcome with lumbar transforaminal epidural spinal procedures. Furthermore, the current study highlights the difficulty of pain evaluation outcome by VRS.
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Randomized Controlled Trial Comparative Study
Lumiracoxib 400 mg compared with celecoxib 400 mg and placebo for treating pain following dental surgery: a randomized, controlled trial.
This randomized, double-blinded, double-dummy, parallel-group, single-center study compared a single dose of the novel selective COX-2 inhibitor lumiracoxib (400 mg), with celecoxib (400 mg) or placebo in dental pain. Patients > or =17 years with moderate-to-severe dental pain were recruited after surgical extraction of 2 or more partially or fully bony impacted molars. Pain intensity was measured using the categorical scale and the primary efficacy variable was the summed pain intensity difference over 8 hours after dosing (SPID-8). Patient disposition and demographics were comparable between lumiracoxib 400 mg (n = 156), celecoxib 400 mg (n = 156), and placebo (n = 52) groups. Lumiracoxib was statistically superior (P < .001) to both celecoxib and placebo in reducing pain intensity (SPID-8; least-squares means: 8.31, lumiracoxib; 4.26, celecoxib; -1.87, placebo). Significantly more patients treated with lumiracoxib (58.9%) considered treatment to be good or excellent compared with celecoxib and placebo (42.3% and 5.7%, respectively; P = .001). Lumiracoxib was superior to celecoxib and placebo for all other secondary efficacy variables. All treatments were well-tolerated. In conclusion, 400 mg lumiracoxib was well-tolerated and provided significantly superior analgesia to 400 mg celecoxib or placebo in patients with moderate-to-severe pain after dental surgery. ⋯ In a randomized, double-blinded, double-dummy, parallel-group, single-center study, a single dose of the novel selective COX-2 inhibitor lumiracoxib (400 mg) was well-tolerated and provided significantly superior analgesia to 400 mg celecoxib or placebo in patients with moderate-to-severe dental pain after surgical extraction of impacted molars.