The journal of pain : official journal of the American Pain Society
-
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.
-
Comparative Study
Neuromodulation of thoracic intraspinal visceroreceptive transmission by electrical stimulation of spinal dorsal column and somatic afferents in rats.
Clinical studies have shown that neuromodulation therapies, such as spinal cord stimulation (SCS) and transcutaneous electrical nerve stimulation (TENS), reduce symptoms of chronic neuropathic and visceral pain. The neural mechanisms underlying SCS and TENS therapy are poorly understood. The present study was designed to compare the effects of SCS and TENS on spinal neuronal responses to noxious stimuli applied to the heart and esophagus. Direct stimulation of an intercostal nerve (ICNS) was used to simulate the effects of TENS. Extracellular potentials of left thoracic (T3) spinal neurons were recorded in pentobarbital anesthetized, paralyzed, and ventilated male rats. SCS (50 Hz, 0.2 ms, 3-5 minutes) at a clinical relevant intensity (90% of motor threshold) was applied on the C1-C2 or C8-T1 ipsilateral spinal segments. Intercostal nerve stimulation (ICNS) at T3 spinal level was performed using the same parameters as SCS. Intrapericardial injection of bradykinin (IB, 10 microg/mL, 0.2 mL, 1 minute) was used as the noxious cardiac stimulus. Noxious thoracic esophageal distension (ED, 0.4 mL, 20 seconds) was produced by water inflation of a latex balloon. C1-C2 SCS suppressed excitatory responses of 16/22 T3 spinal neurons to IB and 25/30 neurons to ED. C8-T1 SCS suppressed excitatory responses of 10/15 spinal neurons to IB and 17/23 neurons to ED. ICNS suppressed excitatory responses of 9/12 spinal neurons to IB and 17/22 neurons to ED. These data showed that SCS and ICNS modulated excitatory responses of T3 spinal neurons to noxious stimulation of the heart and esophagus. ⋯ Neuromodulation of noxious cardiac and esophageal inputs onto thoracic spinal neurons by spinal cord and intercostal nerves stimulation observed in the present study may help account for therapeutic effects on thoracic visceral pain by activating the spinal dorsal column or somatic afferents.
-
Comparative Study
Metoclopramide versus hydromorphone for the emergency department treatment of migraine headache.
We conducted a retrospective cohort study to compare the effects of metoclopramide versus hydromorphone for the initial emergency department treatment of migraine headache at an urban teaching hospital. The primary outcome measure was the mean difference in the subjects' self-reported pain scores before and after the administration of the initial medication treatment. We also estimated crude and adjusted relative risks (using Poisson multivariate regression modeling) to assess and control potential confounding by age, gender, race, and pain score before initial medication. Two hundred subjects were included, with 51 (25.5%) receiving intravenous or intramuscular hydromorphone, 95 (47.5%) receiving intravenous metoclopramide, and 54 (27.0%) receiving 1 of several other medications. Using a standardized pain scale of 0 to 10, mean pain score reductions were 2.3 points for hydromorphone, 3.7 points for metoclopramide, and 2.8 points for all other medications combined (P < .001). When comparing metoclopramide versus hydromorphone, the crude relative risk for pain reduction of 3 or more points was 1.76 (95% CI, 1.12-2.75, P = .01), and the adjusted relative risk was 1.60 (95% CI, 0.84-3.03, P = .15). Metoclopramide also resulted in less use of rescue medications, faster times to discharge, and no difference in the frequency of adverse reactions. ⋯ Metoclopramide appears to be an effective initial medical treatment for migraine headaches in the emergency department setting, but its pharmacologic mechanism remains incompletely understood. A double-blinded, randomized, controlled trial comparing standard dosages of hydromorphone versus metoclopramide will be needed to definitively determine which medication is more effective.
-
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.
-
Opiate analgesic tolerance is defined as a need for higher doses of opiates to maintain pain relief after prolonged opiate exposure. Though changes in the opioid receptor undoubtedly occur during conditions of opiate tolerance, there is increasing evidence that opiate analgesic tolerance is also caused by pronociceptive adaptations in the spinal cord. We have previously observed increased glutamate release in the spinal cord dorsal horn of neonatal rats made tolerant to the opiate morphine. In this study, we investigate whether spinal substance P (SP) and its receptor, the neurokinin 1 (NK1) receptor, are also modulated by prolonged morphine exposure. Immunocytochemical studies show decreased SP- and NK1-immunoreactivity in the dorsal horn of morphine-treated rats, whereas SP mRNA in the dorsal root ganglia is not changed. Electrophysiological studies show that SP fails to activate the NK1 receptor in the morphine-treated rat. Taken together, the data indicate that chronic morphine treatment in the neonatal rat is characterized by a loss of SP effects on the NK1 receptor in lamina I of the neonatal spinal cord dorsal horn. The results are discussed in terms of compensatory spinal cord processes that may contribute to opiate analgesic tolerance. ⋯ This article describes anatomical and physiological changes that occur in the spinal cord dorsal horn of neonatal rats after chronic morphine treatment. These changes may represent an additional compensatory process of morphine tolerance and may represent an additional therapeutic target for the retention and restoration of pain relief with prolonged morphine treatment.