Naozumi Takeshima

Mechanisms of analgesic action of pulsed radiofrequency on adjuvant-induced pain in the rat: Roles of descending adrenergic and serotonergic systems

Pulsed radiofrequency (PRF) has been reported to be effective in the treatment of several types of pain. The mechanism of action, however, is not well known. In a recent study, the antinociceptive effects of acute thermal pain were shown to be mediated via descending pain inhibitory pathways. In this study we observed an analgesic effect of PRF treatment in an adjuvant induced inflammatory pain model in rats. In this model, sciatic nerves were treated with PRF at 37° and 42°, which inhibited hyperalgesia in the inflammatory groups when compared to RF and sham treatment. This effect was attenuated after intrathecal administration of the alpha2‐adrenoceptor antagonist yohimbine, the selective 5‐HT3 serotonin receptor antagonist MDL72222, and the non‐selective serotonin receptor antagonist methysergide. All three drugs were found to significantly inhibit the analgesic effect of PRF. The results suggest that the analgesic action of PRF involves the enhancement of noradrenergic and serotonergic descending pain inhibitory pathways.

Evaluation of the therapeutic results of epiduroscopic adhesiolysis for failed back surgery syndrome

BACKGROUND No data for patients with failed back surgery syndrome (FBSS) based on the location of adhesions separated by epiduroscopic adhesiolysis have been reported. METHODS We performed epiduroscopic adhesiolysis on 28 FBSS patients to examine the impact of differences in the locations of the separated regions on the treatment results. We performed fluoroscopic imaging through the sacral hiatus to assess the condition of adhesions in the epidural space during the post-adhesiolysis observation period. RESULTS In patients in whom only the epidural space was separated by adhesiolysis, there was a significant improvement in the Roland-Morris disability questionnaire (RDQ) score until 12 weeks after adhesiolysis, but the score gradually returned to the preoperative value thereafter. Among patients in whom the nerve root responsible for radicular pain was separated, there was a long-term improvement in the RDQ, Oswestry disability index 2.0 (ODI), and Japanese Orthopedic Association Assessment of Treatment (JOA) scores. Among patients in whom both the epidural space and the nerve root responsible for pain were separated, there was a 12 week improvement in the RDQ score and 24 week improvements in the ODI and JOA scores. CONCLUSIONS Progressive epidural imaging after adhesiolysis suggested that pain was caused by re-adhesion around the nerve root. Since re-adhesion of the nerve root required some time, the effect of adhesiolysis was maintained for extended periods in these cases. We suggest that epiduroscopic adhesiolysis is an effective therapy for FBSS patients, and that adhesiolysis of the nerve root may exhibit the long-term (24 weeks) efficacy in patients with pain.

Ultrasound visibility of regional anesthesia catheters: an in vitro study

Background Ultrasound subjective visibility of in-plane needles is correlated with the intensity difference between the needle surface and the background. Regional anesthesia catheters are difficult to visualize by an ultrasound. In the present study, we investigated the ultrasound visibility of the catheters. Methods Six catheters were placed at 0° and 30° relative to and at a depth of 1 cm below the pork phantom surface. Ultrasound images of in-plane catheters were evaluated, subjectively and objectively. Outer and inner objective visibilities were defined as the difference in the mean pixel intensity between the catheter surface and adjacent background, and between the surface and the center of the catheter, respectively. Evaluations were made based on the portion of the catheters. A P value < 0.05 was considered significant. Results Subjective visibility was more strongly correlated with the inner objective visibility than with the outer objective visibility at both angles. Metallic 19-gauge catheters were more subjectively visible than the non-metallic 20-gauge catheters at 30° degrees (P < 0.01). Subjective, and outer and inner objective visibility were significantly lower at 30° than at 0° (P < 0.01, P < 0.01, P = 0.02). Perifix ONE at 0° and Perifix FX at 30° were the most visible catheters (P < 0.01 for both). Conclusions Subjective visibility of catheters can not be evaluated in the same manner as that of the needles. For the best possible visualization, we recommend selecting a catheter with a structure that enhances the dark at the center of catheter, rather than basing the catheter selection on the bore size.

Olprinone decreases elevated concentrations of cytokine-induced neutrophil chemoattractant-1 in septic rats

PurposeThe diaphragm is one of the organs directly affected by abdominal sepsis. Evidence suggests that sepsis induces diaphragmatic fatigability and that activated neutrophils play a crucial role in the development of diaphragmatic fatigability. In the present study, we investigated whether olprinone, a phosphodiesterase inhibitor, influenced the kinetics of cytokine-induced neutrophil chemoattractant-1 (CINC-1) in the diaphragm under abdominal septic conditions.MethodsMale Wistar rats were randomly assigned to a sham group, a cecal ligation and perforation group, and a phosphodiesterase inhibitor-pretreated group. To measure serial changes in CINC-1 concentrations, the right hemidiaphragm was removed at 4, 8, and 16 h after the surgical procedure in each group.ResultIn the cecal ligation and perforation group, CINC-1 concentrations in the diaphragm were significantly elevated compared with those in the sham group at both 4 and 8 h after the cecal ligation and perforation procedure. In the phosphodiesterase inhibitor-pretreated group, olprinone significantly attenuated the elevated CINC-1 concentrations at both 4 and 8 h after the surgical procedure. However, we observed no statistically significant differences in CINC-1 concentrations between the cecal ligation and perforation group and the phosphodiesterase inhibitor-pretreated groups at 16 h after the surgical procedure.ConclusionOlprinone decreases elevated CINC-1 concentration in the diaphragm under septic conditions. This suggests that olprinone may inhibit neutrophil recruitment to the diaphragm.

A case of perineal pain related to interstitial cystitis which was supposed to be relieved with gabapentin

alleviation of her symptoms for several days, her symptoms recurred. Two months after the cystoscopy, she visited our pain clinic. At that time, her visual analogue scale (VAS) score for pain was 100. We diagnosed her with bladder pain syndrome related to IC, and started oral administration of a combination of paroxetine, etodolac, acetaminophen, and clonazepam. However, these medications had no effect on her symptoms, and she was admitted to our department for nerve block treatment. For this treatment, an epidural catheter was advanced at the L4-5 interspace, and the tip was placed at L3. The pain related to IC almost disappeared after the epidural administration of 5 ml of 1% lidocaine (Fig. 1). She was scheduled to receive 5 ml of 1% lidocaine administered through the epidural catheter periodically, four times a day. However, the epidural administration of 5 ml of 1% lidocaine induced hypotension. Therefore, the dose of 1% lidocaine was decreased to 4 ml. As a result of the decrease in epidural lidocaine administration, the pain related to IC increased. Therefore, oral gabapentin was started, at a dose of 200 mg· day and gradually increased. After the epidural catheter was removed, the superior hypogastric plexus was blocked with 0.75% ropivacaine as a trial. The pain was diminished for a few days after the superior hypogastric plexus blockade. However, she declined permanent block with alcohol because of A case of perineal pain related to interstitial cystitis which was supposed to be relieved with gabapentin

New Anthranilic Acid Derivative, EAntS-GS, Attenuates Freund’s Complete Adjuvant-Induced Acute Pain in Rats

BACKGROUND Acute and chronic pain commonly accompany various clinical conditions such as contusion, fracture, osteoarthritis, peripheral neuropathy, and postherpetic neuralgia. Recent studies have found that antioxidative drugs can have analgesic effects. The present study tested the hypothesis that a new anthranilic acid derivative, EAntS-GS, exerts antinociceptive effects on inflammatory pain in a rat model. METHODS We induced subacute pain with a plantar injection of Freunds complete adjuvant (FCA) in Sprague-Dawley rats. EAntS-GS (1 mg/kg subcutaneous injection or 1% application) was administered every 12 h beginning 24 h after FCA administration, and the plantar test was used to determine its effect on pain. Levels of myeloperoxidase, inducible nitric oxide synthase (iNOS), and protease activated receptor 2 (PAR2) were measured to elucidate the mechanism of action of EAntS-GS. RESULTS EAntS-GS significantly reduced FCA-induced pain and myeloperoxidase, iNOS, and PAR2 levels. Our findings suggest that the new anthranilic acid derivative, EAntS-GS, exerts antinociceptive effects, and that the mechanism involves iNOS and PAR2. CONCLUSION We conclude that EAntS-GS should be considered a new therapeutic tool to treat acute and chronic pain.

Anesthetic management of laparoscopic adjustable gastric banding in Japanese patients with morbid obesity

Laparoscopic adjustable gastric banding (LAGB) is a common type of bariatric surgery worldwide, though not so in Japan. Here we report the anesthetic management of LAGB in ten Japanese patients with morbid obesity. General anesthesia was induced with propofol, fentanyl, and vecuronium bromide and maintained with sevoflurane in oxygen and air (or nitrous oxide in some cases). In a limited number of patients, perioperative epidural analgesia was performed, with fentanyl injected intravenously for analgesia in the remaining patients. Although some special considerations were needed, in perioperative management, including thromboprophylaxis, there were no severe complications in any of the patients.