Experimental Rat Model of Bony Defects in the Facet Joint Maintained with Bone Wax for the Study of Spinal Pain.

PURPOSE: Studies using experimental rat models for low back pain due to facet-joint defects are scarce. This study used a novel experimental rat model to determine whether bony defects induced by facetectomy could be maintained by bone wax, thus mimicking spondylolysis, and to analyze the effect of the facetectomy on rat behavior. PATIENTS AND METHODS: Twelve 10-week-old male Wistar rats weighing 300-350 g were divided into group A (n = 6) that underwent unilateral facetectomy of the right L5-6 facet joint and group B (n = 6) that additionally applied water-soluble bone wax at the facetectomy site. The difference in the left and right stride length, detected by the footprint test, and change in the left and right facet joint area were compared before and 4 weeks after the experiment. RESULTS: Even though the difference between the left and right stride lengths of groups A and B was not statistically significant, in contrast to group A, group B showed a shorter stride length on the right side (p = 0.22 and 0.46, in group A and group B, respectively). The right facet joint area, where the facetectomy was performed, was significantly smaller in group B 4 weeks after surgery, but not in group A (p = 0.50 and < 0.01, in group A and group B, respectively). CONCLUSION: Based on the results, we concluded that the bony defects, induced by facetectomy at the L5-6 facet joint, were maintained with bone wax. This study will provide an experimental model for bony defects in the facet joint.

Comparison of the expression of cluster of differentiation (CD)39 and CD73 between propofol- and sevoflurane-based anaesthesia during open heart surgery.

High expression of cluster of differentiation (CD)39 and CD73 has cardio-protective effects. We hypothesised that the expression of CD39 and CD73 would differ between propofol- and volatile anaesthetic-based anaesthesia in patients undergoing open heart surgery (OHS). The objective of this prospective randomized trial was to compare the changes in CD39 and CD73 levels in CD4+ T cells between propofol- and sevoflurane-based anaesthesia during OHS. The study randomly allocated 156 patients undergoing OHS to a propofol or sevoflurane group. Blood was obtained preoperatively and up to 48 hours after weaning from cardiopulmonary bypass (CPB). The expression levels of CD39 and CD73 in circulating CD4+ T cells, serum cytokines and other laboratory parameters were analysed. The primary outcome was the expression of CD39 and CD73 on CD4+ T cells. Demographic data and perioperative haemodynamic changes did not show significant differences between the two groups. The expression of CD39 and CD73 in the sevoflurane group was significantly lower than in the propofol group (P < 0.001). Other laboratory findings including cardiac enzymes and cytokine levels, did not show significant intergroup differences. Propofol attenuated the decrease in CD39 and CD73 in circulating CD4+ T cells compared to sevoflurane-based anaesthesia during OHS.

Optimal propofol dosage for i-gel® insertion in healthy paralyzed patients.

BACKGROUND: Propofol is used for supraglottic airway device insertion, often with the i-gel. However, the propofol requirement for i-gel insertion has not been explored in paralyzed patients. This study was performed to explore hemodynamic changes and sedation level with different propofol doses in healthy paralyzed patients when the i-gel was inserted. METHODS: A total of 141 patients undergoing a urologic operation were randomly allocated to three groups depending on the propofol dose (1.5, 2, and 2.5 mg/kg; Groups P1.5, P2, and P2.5, respectively). After patients had been administered each propofol dose and rocuronium, the i-gel was inserted and changes in hemodynamic parameters and bispectral index were evaluated. RESULTS: Group P2 showed a lower incidence of complications (17%) such as hemodynamic instability and inadequate sedation than Group P1.5 (55.3%, P < 0.001) or Group P2.5 (40.4%, P = 0.012). The incidence and dose of additional propofol increased in Group P1.5 (51%, median [range]; 20 [0-50]) compared with those in the other groups (0%, 0 [0-0] in Group P2 and 8.5%, 0 [0-50] in Group P2.5, all P < 0.001), and the incidence and dose of additional ephedrine were significantly higher in Group P2.5 (31.9%; 0 [0-20]) than in Group P1.5 (10.6%, P = 0.012; 0 [0-5], P = 0.007, respectively). CONCLUSIONS: For the stable maintenance of hemodynamic parameters and proper sedation level during i-gel insertion, 2 mg/kg propofol has an advantage over 1.5 mg/kg or 2.5 mg/kg propofol in healthy paralyzed patients.

Laparoscopic appendectomy under spinal anesthesia with dexmedetomidine infusion.

BACKGROUND: Laparoscopic appendectomy (LA) is rarely performed under regional anesthesia because of pneumoperitoneum-related problems. We expected that dexmedetomidine would compensate for the problems arising from spinal anesthesia alone. Thus, we performed a feasibility study of spinal anesthesia with intravenous dexmedetomidine infusion. METHODS: Twenty-six patients undergoing LA received spinal anesthesia with intravenous dexmedetomidine infusion. During surgery, the patient's pain or discomfort was controlled by supplemental fentanyl or ketamine injection, and all adverse effects were evaluated. RESULTS: No patient required conversion to general anesthesia, and all operations were completed laparoscopically without conversion to open surgery. Seventeen (65.4%) patients required supplemental injection of fentanyl or ketamine. Bradycardia occurred in seven (26.9%) patients. CONCLUSIONS: Spinal anesthesia with dexmedetomidine infusion may be feasible for LA. However, additional analgesia, sedation, and careful attention to the potential development of bradycardia are needed for a successful anesthetic outcome.

Clinical effects of intrathecal fentanyl on shoulder tip pain in laparoscopic total extraperitoneal inguinal hernia repair under spinal anaesthesia: a double-blind, prospective, randomized controlled trial.

OBJECTIVE: The study evaluated the clinical intraoperative effects of intrathecal administration of fentanyl on shoulder tip pain in patients undergoing laparoscopic total extraperitoneal inguinal hernia repair (TEP) under spinal anaesthesia. METHODS: Patients undergoing TEP were allocated in a double-blinded, prospective, randomized manner to two groups. Spinal anaesthesia was induced by intrathecal administration of 2.8 ml of 0.5% hyperbaric bupivacaine (14 mg) in the control group and with 2.6 ml of 0.5% hyperbaric bupivacaine (13 mg) and 10 µg fentanyl (0.2 ml) in the experimental group. RESULTS: The quality of muscle relaxation, adequacy of operative space and incidence of pneumoperitoneum were similar in the two groups (n = 36 per group). Compared with the control group, the experimental group had significantly fewer cases of hypotension (12 [33.3%]) versus 23 [63.9%]) and shoulder tip pain (nine [25%] versus 18 [50%]). Intraoperative shoulder tip pain was more severe in the control group than in the experimental group. CONCLUSIONS: Addition of intrathecal fentanyl to local anaesthetic can relieve shoulder tip pain with no change in complications, especially hypotension, during TEP under spinal anaesthesia.

Antinociceptive effect of phenyl N-tert-butylnitrone, a free radical scavenger, on the rat formalin test.

BACKGROUND: Reactive oxygen species (ROS) such as superoxide radicals, hydrogen peroxide, nitric oxide, and nitroperoxide, cause oxidative stress which interferes with normal cell functioning, resulting in cell damage. It is reported to be associated with chronic pain, especially neuropathic pain, and inflammatory pain. ROS is also closely related to central sensitization. Therefore, this study was designed to explore the effects of Phenyl N-tert-butylnitrone (PBN), an ROS scavenger, in acute, continuous, and increasing pain caused by central sensitization. METHODS: Male Sprague-Dawley rats were divided into 2 groups, an intraperitoneal group (IP) and an intrathecal group (IT), and once again divided into an experimental group and a control group. The experimental group was injected with Phenyl N-tert-butylnitrone (PBN), a free radical scavenger, either intraperitoneally or intrathecally. After inducing pain by injecting formalin into the hind paw, pain behaviors were measured. Lumbar enlargement immmunohistochemistry was performed to assess nitrotyrosine, an oxidative stress marker, to identify the degree of protein nitration. RESULTS: Both experimental groups of IP and IT showed statistically significant decreases in the number of flinches compared to the control group in phase 1 and 2. Immunohistochemical evaluation in the control group revealed an increase in nitrated proteins in the gray matter of the lumbar spinal cord, but a significant decrease in nitrated proteins in the gray matter of lumbar spinal cord of the experimental group. CONCLUSIONS: Intraperitoneal and intrathecal administration of PBN decreases analgesic behaviors, allowing us to believe that ROS is mainly responsible for acute pain and central sensitization.

A comparison of infraclavicular and supraclavicular approaches to the brachial plexus using neurostimulation.

BACKGROUND: A prospective, double blind study was performed to compare the clinical effect of vertical infraclavicular and supraclavicular brachial plexus block using a nerve stimulator for upper limb surgery. METHODS: One hundred patients receiving upper limb surgery under infraclavicular or supraclavicular brachial plexus block were enrolled in this study. The infraclavicular brachial plexus block was performed using the vertical technique with 30 ml of 0.5% ropivacaine. The supraclavicular brachial plexus block was performed using the plumb bob technique with 30 ml of 0.5% ropivacaine. The block performance-related pain was evaluated. This study observed which nerve type was stimulated, and scored the sensory and motor block. The quality of the block was assessed intra-operatively. The duration of the sensory and motor block as well as the complications were assessed. The patient's satisfaction with the anesthetic technique was assessed after surgery. RESULTS: There were no significant differences in the block performance-related pain, frequency of the stimulated nerve type, evolution of sensory and motor block quality, or the success of the block. There were no significant differences in the duration of the sensory and motor block. There was a significant difference in the incidence of Horner's syndrome. Two patients had a pneumothorax in the supraclavicular approach. There were no significant differences in the patient's satisfaction. CONCLUSIONS: Both infraclavicular and supraclavicular brachial plexus block had similar effects. The infraclavicular approach may be preferred to the supraclavicular approach when considering the complications.