Korean Journal of Pain最新文献

Background: Ferrostatin-1 and liproxstatin-1, both ferroptosis inhibitors, protect cells. Liproxstatin-1 decreases morphine tolerance. Yet, ferrostatin-1's effect on morphine tolerance remains unexplored. This study aimed to evaluate the influence of ferrostatin-1 on the advancement of morphine tolerance and understand the underlying mechanisms in male rats.

Methods: This experiment involved 36 adult male Wistar albino rats with an average weight ranging from 220 to 260 g. These rats were categorized into six groups: Control, single dose ferrostatin-1, single dose morphine, single dose ferrostatin-1 + morphine, morphine tolerance (twice daily for five days), and ferrostatin-1 + morphine tolerance (twice daily for five days). The antinociceptive action was evaluated using both the hot plate and tail-flick tests. After completing the analgesic tests, tissue samples were gathered from the dorsal root ganglia (DRG) for subsequent analysis. The levels of glutathione, glutathione peroxidase 4 (GPX4), and nuclear factor erythroid 2-related factor 2 (Nrf2), along with the measurements of total oxidant status (TOS) and total antioxidant status (TAS), were assessed in the tissues of the DRG.

Results: After tolerance development, the administration of ferrostatin-1 resulted in a significant decrease in morphine tolerance (P < 0.001). Additionally, ferrostatin-1 treatment led to elevated levels of glutathione, GPX4, Nrf2, and TOS (P < 0.001), while simultaneously causing a decrease in TAS levels (P < 0.001).

Conclusions: The study found that ferrostatin-1 can reduce morphine tolerance by suppressing ferroptosis and reducing oxidative stress in DRG neurons, suggesting it as a potential therapy for preventing morphine tolerance.

Background: Tolerance to the analgesic effects of opioids and non-steroidal anti-inflammatory drugs (NSAIDs) is a major concern for relieving pain. Thus, it is highly valuable to find new pharmacological strategies for prolonged therapeutic procedures. Biguanide-type drugs such as metformin (MET) are effective for neuroprotection and can be beneficial for addressing opioid tolerance in the treatment of chronic pain. It has been proposed that analgesic tolerance to NSAIDs is mediated by the endogenous opioid system. According to the cross-tolerance between NSAIDs, especially sodium salicylate (SS), and opiates, especially morphine, the objective of this study was to investigate whether MET administration can reduce tolerance to the anti-nociceptive effects of SS.

Methods: Fifty-six male Wistar rats were used in this research (weight 200-250 g). For induction of tolerance, SS (300 mg/kg) was injected intraperitoneally for 7 days. During the examination period, animals received MET at doses of 50, 75, or 100 mg/kg for 7 days to evaluate the development of tolerance to the analgesic effect of SS. The hot plate test was used to evaluate the drugs' anti-nociceptive properties.

Results: Salicylate injection significantly increased hot plate latency as compared to the control group, but the total analgesic effect of co-treatment with SS + Met50 was stronger than the SS group. Furthermore, the effect of this combination undergoes less analgesic tolerance over time.

Conclusions: It can be concluded that MET can reduce the analgesic tolerance that is induced by repeated intraperitoneal injections of SS in Wister rats.

Background: Radiofrequency ablation is an effective treatment modality in the symptomatic treatment of knee osteoarthritis. Our aim was to compare the efficacy of radiofrequency ablation of the superomedial and inferomedial genicular nerves (2 branches) with the superolateral, superomedial, and inferomedial genicular nerves (3 branches) and to show whether the 2-branch procedure is inferior to the 3-branch procedure.

Methods: This study is a prospective, randomized, single-blind clinical study. Eligible participants were randomized into 2 groups: group A, which applied the procedure to the superomedial and inferomedial genicular nerves, and group B, which applied it to the superomedial, superolateral and inferomedial genicular nerves. Pain was evaluated with the numerical rating scale, quality of life with the Short Form-36 (SF-36), and disability with the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index before, and at 1 and 3 months after the procedure.

Results: A total of 41 patients were included. There were no differences between the groups except for the SF-36 physical health sub-score at baseline. A significant improvement was seen in the numeric rating scale (NRS) score, SF-36 sub-scores, WOMAC Index total, as well as pain and physical function scores in both groups, though no significant difference was detected between the groups during follow-up.

Conclusions: Although we were unable to establish the noninferiority of conventional radiofrequency ablation (CRFA) applied to 2 branches to CRFA applied to 3 branches, in this trial, significant and similar improvement was observed in NRS, WOMAC total, pain, and physical function and SF-36 scores in both groups.

This review explores the essential methodologies for effective postoperative pain management, focusing on the need for thorough pain assessment tools, as underscored in various existing guidelines. Herein, the strengths and weaknesses of commonly used pain scales for postoperative pain-the Visual Analog Scale, Numeric Rating Scale, Verbal Rating Scale, and Faces Pain Scale-are evaluated, highlighting the importance of selecting appropriate assessment tools based on factors influencing their effectiveness in surgical contexts. By emphasizing the need to comprehend the minimal clinically important difference (MCID) for these scales in evaluating new analgesic interventions and monitoring pain trajectories over time, this review advocates recognizing the limitations of common pain scales to improve pain assessment strategies, ultimately enhancing postoperative pain management. Finally, five recommendations for pain assessment in research on postoperative pain are provided: first, selecting an appropriate pain scale tailored to the patient group, considering the strengths and weaknesses of each scale; second, simultaneously assessing the intensity of postoperative pain at rest and during movement; third, conducting evaluations at specific time points and monitoring trends over time; fourth, extending the focus beyond the intensity of postoperative pain to include its impact on postoperative functional recovery; and lastly, interpreting the findings while considering the MCID, ensuring that it is clinically significant for the chosen pain scale. These recommendations broaden our understanding of postoperative pain and provide insights that contribute to more effective pain management strategies, thereby enhancing patient care outcomes.

There are growing concerns regarding the safety of long-term treatment with opioids of patients with chronic non-cancer pain. In 2017, the Korean Pain Society (KPS) developed guidelines for opioid prescriptions for chronic non-cancer pain to guide physicians to prescribe opioids effectively and safely. Since then, investigations have provided updated data regarding opioid therapy for chronic non-cancer pain and have focused on initial dosing schedules, reassessment follow-ups, recommended dosage thresholds considering the risk-benefit ratio, dose-reducing schedules for tapering and discontinuation, adverse effects, and inadvertent problems resulting from inappropriate application of the previous guidelines. Herein, we have updated the previous KPS guidelines based on a comprehensive literature review and consensus development following discussions among experts affiliated with the Committee on Hospice and Palliative Care in the KPS. These guidelines may assist physicians in prescribing opioids for chronic non-cancer pain in adult outpatient settings, but should not to be regarded as an inflexible standard. Clinical judgements by the attending physician and patient-centered decisions should always be prioritized.

Nociplastic pain by the "International Association for the Study of Pain" is defined as pain that arises from altered nociception despite no clear evidence of nociceptive or neuropathic pain. Augmented central nervous system pain and sensory processing with altered pain modulation are suggested to be the mechanism of nociplastic pain. Clinical criteria for possible nociplastic pain affecting somatic structures include chronic regional pain and evoked pain hypersensitivity including allodynia with after-sensation. In addition to possible nociplastic pain, clinical criteria for probable nociplastic pain are pain hypersensitivity in the region of pain to non-noxious stimuli and presence of comorbidity such as generalized symptoms with sleep disturbance, fatigue, or cognitive problems with hypersensitivity of special senses. Criteria for definitive nociplastic pain is not determined yet. Eight specific disorders related to central sensitization are suggested to be restless leg syndrome, chronic fatigue syndrome, fibromyalgia, temporomandibular disorder, migraine or tension headache, irritable bowel syndrome, multiple chemical sensitivities, and whiplash injury; non-specific emotional disorders related to central sensitization include anxiety or panic attack and depression. These central sensitization pain syndromes are overlapped to previous functional pain syndromes which are unlike organic pain syndromes and have emotional components. Therefore, nociplastic pain can be understood as chronic altered nociception related to central sensitization including both sensory components with nociceptive and/or neuropathic pain and emotional components. Nociplastic pain may be developed to explain unexplained chronic pain beyond tissue damage or pathology regardless of its origin from nociceptive, neuropathic, emotional, or mixed pain components.

Background: : This study aimed to identify exact anatomical landmarks and ideal injection volumes for safe adductor canal blocks (ACB).

Methods: : Fifty thighs from 25 embalmed adult Korean cadavers were used. The measurement baseline was the line connecting the anterior superior iliac spine (ASIS) to the midpoint of the patellar base. All target points were measured perpendicular to the baseline. The relevant cadaveric structures were observed using ultrasound (US) and confirmed in living individuals. US-guided dye injection was performed to determine the ideal volume.

Results: : The apex of the femoral triangle was 25.3 ± 2.2 cm distal to the ASIS on the baseline and 5.3 ± 1.0 cm perpendicular to that point. The midpoint of the superior border of the vasto-adductor membrane (VAM) was 27.4 ± 2.0 cm distal to the ASIS on the baseline and 5.0 ± 1.1 cm perpendicular to that point. The VAM had a trapezoidal shape and was connected as an aponeurosis between the medial edge of the vastus medialis muscle and lateral edge of the adductor magnus muscle. The nerve to the vastus medialis penetrated the muscle proximal to the superior border of the VAM in 70% of specimens. The VAM appeared on US as a hyperechoic area connecting the vastus medialis and adductor magnus muscles between the sartorius muscle and femoral artery.

Conclusions: : Confirming the crucial landmark, the VAM, is beneficial when performing ACB. It is advisable to insert the needle obliquely below the superior VAM border, and a 5 mL injection is considered sufficient.

Background: Neck and jaw pain is common and is associated with jaw functional limitations, postural stability, muscular endurance, and proprioception. This study aimed to investigate the effect of jaw and neck pain on craniocervico- mandibular functions and postural stability in patients with temporomandibular joint disorders (TMJDs).

Methods: Fifty-two patients with TMJDs were included and assessed using Fonseca's Questionnaire and the Helkimo Clinical Dysfunction Index. An isometric strength test was performed for the TMJ depressor and cervical muscles. The TMJ position sense (TMJPS) test and cervical joint position error test (CJPET) were employed for proprioception. Total sway degree was obtained for the assessment of postural stability. Deep neck flexor endurance (DNFE) was assessed using the craniocervical flexion test. The mandibular function impairment questionnaire (MFIQ) was employed to assess mandibular function, and the craniovertebral angle (CVA) was measured for forward head posture.

Results: Jaw and neck pain negatively affected CVA (R² = 0.130), TMJPS (R² = 0.286), DNFE (R² = 0.355), TMJ depressor (R² = 0.145), cervical flexor (R² = 0.144), and extensor (R² = 0.148) muscle strength. Jaw and neck pain also positively affected CJPET for flexion (R² = 0.116) and extension (R² = 0.146), as well as total sway degree (R² = 0.128) and MFIQ (R² = 0.230).

Conclusions: Patients with painful TMJDs, could have impaired muscle strength and proprioception of the TMJ and cervical region. The jaw and neck pain could also affect postural stability, and the endurance of deep neck flexors as well as mandibular functions in TMJDs.