[A clinical trial of ultrasound-guided facet joint block in the lumbar spine to treat facet joint related low back pain].

OBJECTIVE: To determine the feasibility and clinical efficacy of ultrasound-guided facet joint injection and nerve block in lumbar facet joint for the treatment of facet-joint related low back pain. METHODS: 20 patients with facet-joint pain were randomized into two groups received block blindly (B group) or guided by ultrasound (US group) respectively. The location of needle tip was confirmed by CT in both groups, and the accuracy was computed afterwards. VAS score, puncture time and one-time puncture success rate (%) were recorded. VAS scores and pain remission rates in both groups were recorded at 30 min, 1 d, 2 d, 6 weeks after the block. RESULTS: The VAS scores were 3.3 +/- 0.4 in US group and 1.2 +/- 0.3 in B group (P < 0.05). The puncture time was (206 +/- 27) s in US group while (397 +/- 31) s in B group (P < 0.05). There were 37 facet joint blocks guided by ultrasound, in which 32 were correctly targeted with the first puncture. The success rate is 86.5%. There were 35 facet joint blocks blindly, in which 11 were correctly targeted with the first puncture. The success rate is 31.4%. The difference of one-time puncture success rate between the two groups was significant (P < 0.05). Differences of VAS and pain remission rate at half an hour after facet joint injection between B group and US group were significant (P < 0.05). There were 8, 9, 9, and 9 patients in US group obtaining a reduction in VAS scores > or = 3 at 30 min, 1 d, 2 d and 6 weeks after the procedure respectively, while the numbers of such patients were 5, 6, 5, 5 in B group (P > 0.05). After 6 weeks of follow-up, the overall remission rates were (72.3 +/- 14.0)% in US group, and (56.7 +/- 11.0)% in B group, there was no significant difference between the two groups (P > 0.05). CONCLUSION: The ultrasound-guided lumbar facet joint injection technique had a high feasibility and accuracy, and had better clinical efficacy than block blindly.

[Mechanical hyperalgesia induced by chronic morphine administration in young rats].

OBJECTIVE: To investigate the effects of chronic morphine administration on pain behaviors in young rats and to explore the mechanisms involved. METHODS: Sixteen SD young rats of 3-4 weeks were randomly divided into control and morphine administration groups. Young rats received saline (1 mL/kg) or morphine (10 mg/kg) subcutaneously. Each regimen was given once daily for 14 days. Pain behaviors were examined on day 1, 3, 5, 7, and 14 before the daily drug administration. Western blot was used to examine the expression of glutamate decarboxylase 65 (GAD65) in the spinal cord dorsal horn on day 14 after the last drug administration. RESULTS: Following 14 days of morphine administration, mechanical hyperalgesia was induced in young rats. Compared with control group, the mechanical withdrawal threshold of morphine group significantly decreased on days 3, 5,7 and 14. Chronic administration of morphine downregulated the expression of GAD65 in the spinal cord dorsal horn of young rats. CONCLUSION: Chronic morphine administration could induce mechanical hyperalgesia in young rats, and the downregulation of GAD65 in the spinal cord dorsal horn might play a critical role in the molecular mechanisms of morphine-induced hyperalgesia.

[Feasibility and accuracy of ultrasound-guided methodology in the examination of lumbar spine facet joints].

OBJECTIVE: To investigate the feasibility, accuracy of B ultrasound in the examination of joint space of lumbar spine facet joints compared with CT scan. METHODS: Ten healthy adult volunteers were enrolled. The joint space of lumbar facet joints was measured by ultrasound. To identify the spinal levels, the posterior parasagittal sonograms were obtained at levels L1 to S1. The lumbar facet joints were delineated with the help of transverse sonograms at each level. Meanwhile, the lumbar facet joints were evaluated by spiral CT on the same plane, reformatted to 1-mm axial slices. RESULTS: A total of 88 lumbar facet joints from L1 to S1 were clearly visualized in the 10 volunteers. Both ultrasound and CT measurements showed the same average depth and lateral distance of lumbar facet joint space (P > 0.05). CONCLUSION: The lumbar facet joint space can be accurately demonstrated by ultrasound.

[Effect of preemptive intrathecal lornoxicam on foot swelling of formalin test in rats].

OBJECTIVE: To investigate the anti-inflammatory effect of preemptive intrathecal Lornoxicam on foot swelling of formalin test in rats. METHODS: Eighteen healthy male adult Sprague-Dawley (SD) rats (about 250 g) were randomized into 3 groups: intrathecal solvent group (group S, solvent 20 microL), intramuscular Lornoxicam group (group IM, Lornoxicam 300 microg/20 microL) and intrathecal Lornoxicam group (group IT, Lornoxicam 300 microg/20 microL). After measuring the basic volumes of the left hind paws, rats were injected with corresponding solution intrathecally or intramuscularly, and followed by an intra-plantar administration of 100 microL of 5% formalin 10 minutes later. The volumes of left hind paws were measured again at 10 min, 30 min, 1 h, 2 h, 3 h, 4 h, 24 h after formalin injection. RESULTS: There was no statistical difference of weights or basic volumes among three groups. At 10 min after formalin injection, the left hind paw volume of group IT [(1.53 +/- 0.06) mL] were smaller than that of group S [(1.67 +/- 0.09) mL], P=0.039, but there was no statistically difference between group IT and group IM [(1.65 +/- 0.06) mL]. At 30 min after formalin injection, the left hind paw volume of group S [(1.88 +/- 0.88) mL] was larger than that of group IM [(1.77 +/- 0.05) mL, P<0.05] and group IT [(1.61 +/- 0.06) mL, P<0.01]. The feet swelling degree of group IT was less than that of group IM, P<0.05. At 1 h, 2 h and 3 h after formalin injection, the left hind paw volume of group S was similar to that of group IM, and the volume of group IT was smaller than the other two groups. At 4 h and 24 h after formalin injection, there were no statistic differences of the left hind paw volume among the three groups. CONCLUSION: At 10 min to 3 h after formalin injection, swelling of rat feet induced by formalin was alleviated by preemptive intrathecal Lornoxicam.

[Validating the Oswestry Disability Index in patients with low back pain in Sichuan].

OBJECTIVE: To test the reliability and validity of the Oswestry Disability Index (ODI) in patients with low back pain in China. METHODS: Eighty six patients (female 51, male 35, average age 39.5 +/- 10.1) with chronic low back pain were assessed with the ODI. The assessment was repeated 48 hours after the first test. RESULTS: The Cronbach' Alpha coefficient for the ODI was 0.891. The intraclass correlation coefficient (ICC) for the repeated tests was 0.854 (95% CI = 0.775-0.905). The exploratory factor analysis extracted two factors, which accounted for 61.91% of the total variance. Significant correlations were found between the ODI and the 6 domains of the SF-36. CONCLUSION: The Chinese version of Oswestry Disability Index has satisfactory reliability and validity. It can be used as an instrument for assessing chronic low back pain-related disability.

[Effects of preemptively injected intrathecal lornoxicam on behavior and c-fos protein expression of rat with formalin hurting].

OBJECTIVE: The objective of this study was to investigate an antinociceptive effect of preemptive intrathecal lornoxicam on behavior and expression of c-Fos protein in the spinal cord of the formalin hurting rats. METHODS: Forty-two healthy male adult SD rats (200-250 g) were randomized into 7 groups. In the normal saline control group (group NS), 20 microL of normal saline was injected intrathecally, which was followed by a subcutaneous administration of 100 microL of normal saline into the hind plantar skin of rats 10 min later. In the formalin control group (group FOR), 20 microL of normal saline was injected intrathecally, and followed by rat intraplantar administration of 100 microL of 5% formalin. In the intrathecal lornoxicam experiment groups (groups L60-300), lornoxicam 60, 120, 180, 240, and 300 micdrog were administered intrathecally, respectively, and followed by rat intra-plantar administration of 100 microL of 5% formalin. The graded pain behavior was observed and the nociceptive behavior index (NBI) was calculated per 5 min during one hour immediately after the intra-plantar injection. At the 2-hour time point, all the rats were deeply anesthetized and perfused intracardially; and then, the spinal cord was removed for analysis of c-Fos protein-like immunoreactive neurons (FLIN) at the dorsal horn in the L4-L6 segments. The Student-Newman-Keuls test was used to identify the differences between groups,and correlation analysis was used to demonstrate the relationship between rat behavior and c-Fos expression. RESULTS: Almost no pain response was observed in group NS. The typical biphasic pain response was observed in the formalin-injected groups. In phase I, no difference in the NBI was found between the formalin-injected groups except group L240 and group L300 in which NBI were significantly smaller than that in other formalin-injected groups. In phase II, the cumulative NBI in phase II decreased with the increase in lornoxicam dosage, but the difference was not significant when the dosage above 180 microg. (2) Both in the superficial and deep laminae at the dorsal horn, the amount of FLIN of group NS was much less than that of the remaining groups. The amount of FLIN decreased with the increase in the lornoxicam dosage, but the difference was not significant when the dosage above 180 microg in the superficial lamina and above 240 microg in the deep lamina. (3) Correlation analysis showed that the correlation coefficient between the sum of NBI in one hour and the expression of c-Fos in the superfacial or deep lamina of dorsal horn was positive. CONCLUSION: Pre-intrathacal lornoxicam can successfully inhibit nociceptive behavior and c-Fos expression in spinal dorsal horn of formalin test rats. This effect is correlated with the dosage of lornoxicam and has ceiling phenomenon.

[Effect of clofibrate on myocardial triglyceride accumulation in female obese Zucker rats].

OBJECTIVE: To determine the effect of clofibrate on myocardial triglyceride accumulation in female obese Zucker rats and its role in lipotoxic heart disease. METHODS: Twenty four female Zucker rats were divided into four groups: lean rats+vehicle, lean rats+clofibrate, obese rats + vehicle, obese rats+clofibrate. Daily intraperitoneal injection of clofibrate (300 mg/kg) or vehicle (olive oil, 1 mL/kg) was given to the rats for two weeks. Plasma glucose, insulin, free fatty acids, triglycerdies, cholesterol, and cardiac triglycerdies and fatty acids were measured. RESULTS: Clofibrate normalized plasma free fatty acid and cholesterol and reduced plasma triglyceride and insulin in obese rats. However, clofibrate led to accumulation of heart TG and increased myocardial long-chain unsaturated and monounsaturated fatty acids in obese rats. CONCLUSION: Clofibrate aggravates myocardial triglyceride accumulation in female obese Zucker rats. Further studies are needed for the use of clofibrate in treating cardiac lipid accumulation.

[Effects of intrathecal lornoxicam on withdrawal thresholds of rats to mechanical and thermal stimuli].

OBJECTIVE: To assess the effects of intrathecal lornoxicam on the withdrawal thresholds of rats to mechanical and thermal stimuli. METHODS: After approval of the animal ethic committee, 18 healthy male adult rats were randomly allocated on average to receive the intrathecal solvent (Group S) 20 tL, intramuscular lornoxicam (Group IM) 120 microg/20 microL or intrathecal lornoxicam (Group IT) 120 microg/20 microL, and to do the mechanical withdrawal threshold measured by Dynamic Planter Aesthesiometer (Ugo Basile, Italy). Another 18 rats were allocated similarly to do the thermal withdrawal threshold measured by Hargreaves Test (Ugo Basile, Italy). The basal value of withdrawal threshold was first recorded, and then the intrathecal solvent, intramuscular or intrathecal lornoxicam was injected, and the withdrawal threshold values were measured once more in the period of total 150 min with each 30 min as a time section. The Student-Newman-Keuls test was used to identify the differences between groups, with the SPSS11.5 package. RESULTS: In Group S, there was no difference between the threshold values after intrathecally injecting solvent and the basal value. In Group IM, 30 min after injection, the mechanical and thermal threshold values reached the peak [(31.1 +/- 4.05) g, (20.82 +/- 2.15)], and were different as compared with the basal value (P < 0.05, P < 0.01). The mechanical and thermal withdrawal threshold values decreased to the basal level at 60 min and 90 min respectively. In Group IT, 10 min after injection, the mechanical and thermal withdrawal threshold values [(35.0 +/- 2.76) g, (26.72 +/- 3.75) s] were different when compared with the basal value (P < 0.01). The mechanical and thermal withdrawal threshold values decreased to the basal level at 90 min and 120 min respectively. There was no difference of the basal value among the three groups. But at 10, 30, 60 min after lornoxicam administrated, the mechanical threshold values of Group IT were obviously higher than those of Group S; and at 10, 30 min, it was significantly higher than that of Group IM. At 10, 30, 60, 90 min, the thermal thresholds of Group IT were markedly higher than those of the other groups. CONCLUSION: Both systemic and intrathecal lornoxicam can elevate the withdrawal threshold values of rats to mechanical and thermal stimuli, but the onset of this effect is faster, and the maintenance is longer by intrathecal route.

[Analgesic actions after local peripheral administration of Lornoxicam in a model of formalin test in the rat].

OBJECTIVE: To investigate analgesic actions after local peripheral administration of Lornoxicam in an animal model of formalin test. METHODS: Male Spague-Dawley rats were randomly divided into 3 groups, namely the control, the ipsilateral and the contralateral groups. Each group consisted of 8 rats. Thirty minutes prior to subcutaneous injections of 20 g/L formalin 50 microl into the plantar surface of the right hind-paw, the rats of ipsilateral group received Lornoxicam in the plantar surface of the right hind-paw, and the rats of contralateral group received Lornoxicam in the contralateral plantar surface of the hindpaw. Pain response was recorded for a period of 60 minutes. The summation of time (in seconds) spent in licking and biting responses to the injected paw during each 5 minutes block was analyzed for comparison. RESULTS: The pain response in the first phase (from 0 to 10 minutes) was not inhibited (P > 0.05). The pain response in the second phase (from 10 to 60 minutes) was inhibited in the ipsilateral group (P < 0.05). CONCLUSION: Local peripheral administration of Lornoxicam has analgesic effect on the rat's planta in the second phase of a formalin test model; the mechanism involved is mainly local, but not systemic.

Quantitative and fiber-selective evaluation of dose-dependent nerve blockade by intrathecal lidocaine in rats.

We investigated whether cutaneous stimulus threshold (CST), as determined using a Neurometer, could be used for quantitative and differential nerve evaluation of reversible and irreversible nerve block following intrathecal lidocaine administration in rats. Rats with intrathecal catheters were randomly assigned to one of five groups (saline or 2, 5, 10, or 20% lidocaine). Prior to and 4 days after drug administration, CST was determined at 5, 250, and 2000 Hz. In the 2% lidocaine group, CST from end of lidocaine infusion to recovery from anesthesia was also monitored. Skin-clamp testing and gait observation were performed for comparison with CST findings. Behavioral examinations revealed persistent sensory or motor impairment lasting 4 days in groups receiving >/=5% lidocaine but not in the saline and 2% lidocaine groups. With 2% lidocaine, return to baseline CSTs at 5 and 250 Hz was delayed compared with thresholds at 2000 Hz. Although CSTs in the 5% group at 5 and 250 Hz increased significantly, thresholds at 2000 Hz did not differ from those in rats administered saline. CSTs with >/=10% lidocaine displayed no differences between frequencies. At each frequency, CSTs for rats with >/=5% lidocaine increased in a clearly concentration-dependent manner. These results suggest that CST testing enables evaluation of the different nerve functions for Abeta, Adelta, and C fibers in rats for lidocaine concentrations

[Effect of clonidine on rat's behavior response and spinal nitric oxide in formalin test].

OBJECTIVE: To assess the effect of Clonidine on SD rat's behavior response and spinal nitric oxide in the formalin test. METHODS: The effects of Clonidine (Clo), L-arginine(L-Arg), and NG-nitro-L-arginine (L-NAME) on the flinching and licking time of rats in the formalin test were assessed using the model of formalin-induced hyperalgia. RESULTS: The flinching and licking time of group Clo was shorter (38.60 +/- 17.34) s/5 min than that of group Formalin(155.41 +/- 22.04) s/5 min. Pre-administration of L-Arg could potentiate the Clonidine-induced response; pre-administration of L-NAME could reduce the Clonidine-induced response. CONCLUSION: Spinal nitric oxide release might be one of the antinociception mechanisms of Clonidine in the formalin test.