In terms of antinociceptive action, the main mode of action of magnesium involves its antagonist action at the N-methyl-d-aspartate (NMDA) receptor, which prevents central sensitization and attenuates preexisting pain hypersensitivity. Given the pivotal function of NMDA receptors in pain transduction, magnesium has been investigated in a variety of pain conditions. The oral and parenteral administration of magnesium via the intravenous, intrathecal, or epidural route may alleviate pain and perioperative anesthetic and analgesic requirements. These beneficial effects of magnesium therapy have also been reported in patients with neuropathic pain, such as malignancy-related neurologic symptoms, diabetic neuropathy, postherpetic neuralgia, and chemotherapy-induced peripheral neuropathy. In addition, magnesium treatment is reportedly able to alleviate fibromyalgia, dysmenorrhea, headaches, and acute migraine attacks. Although magnesium plays an evolving role in pain management, better understanding of the mechanism underlying its antinociceptive action and additional clinical studies is required to clarify its role as an adjuvant analgesic.

Ultrasound-guided erector spinae plane block (ESPB), a recent regional analgesic technique, has been used to manage acute pain after surgery. The aim of this meta-analysis is to identify the benefits of ESPB in patients undergoing laparoscopic cholecystectomy (LC). The authors searched PubMed, EMBASE, CENTRAL, CINAHL, and Web of Science to identify all randomized controlled trials (RCTs) evaluating the effects of ESPB on postoperative pain after LC. Primary outcome was defined as 24 h cumulative opioid consumption. Secondary outcomes were pain scores and the incidence of postoperative nausea and vomiting (PONV). We estimated mean differences (MD) and odds ratio (OR) using a random-effects model. A total of 8 RCTs, including 442 patients, were included in the final analysis. Postoperative opioid consumption was significantly lower in the ESPB group than in the control group (MD −4.72, 95% CI −6.00 to −3.44, p < 0.001). Compared with the control group, the ESPB group also showed significantly lower pain scores and incidence of PONV. A separate analysis of RCTs comparing ESPB with oblique subcostal transversus abdominis plane (OSTAP) block showed that the analgesic efficacy of ESPB was similar to that of OSTAP block. The results of this meta-analysis demonstrated that ESPB may provide effective postoperative analgesia in patients undergoing LC.

This meta-analysis aimed to determine whether peripheral nerve blocks (PNB) reduce postoperative delirium (POD) in elderly patients undergoing hip surgery. This study was registered in the International Prospective Register of Systematic Reviews (PROSPERO; CRD42022328320). The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched for randomized controlled trials (RCTs) on 26 April 2022. A total of 19 RCTs with 1977 participants were included. Perioperative PNB lowered the POD incidence on the third postoperative day (OR: 0.59, 95% CI [0.40 to 0.87], p = 0.007, I² = 35%), in patients without underlying cognitive impairment (OR: 0.47, 95% CI [0.30 to 0.74], p = 0.001, I² = 30%), and when a fascia iliaca compartment block (OR: 0.58, 95% CI [0.37 to 0.91], p = 0.02, I² = 0%) or a femoral nerve block (OR: 0.33, 95% CI [0.11 to 0.99], p = 0.05, I² = 66%) were performed. The pain score was also reduced (SMD: −0.83, 95% CI [−1.36 to −0.30], p = 0.002, I² = 95%) after PNB. Perioperative PNB can lower the POD incidence and pain scores up to the third postoperative day. However, considering the wide variety of PNBs performed, more trials are needed to identify the effects of each PNB on POD.

We aimed to investigate whether perioperative magnesium sulfate administration was associated with the incidence of chronic persistent postoperative pain (PPP) following total knee arthroplasty (TKA). This retrospective observational study was performed at a single tertiary academic hospital. We reviewed the medical records of adult patients who were admitted between August 2012 and July 2017. Patients who received magnesium sulfate during surgery were the magnesium group. The presence of PPP, one year after TKA, was evaluated using a binary logistic regression analysis. A total of 924 patients were included in the analysis, and 148 patients (16.0%) experienced PPP one year after TKA. In the multivariable model, the magnesium group had a 62% lower rate of PPP one year after TKA compared to the control group (odds ratio (OR): 0.38, 95% confidence interval (CI): 0.16 to 0.90; p = 0.027). This finding was similar in the sensitivity analysis using propensity score adjustment (OR: 0.38, 95% CI: 0.16 to 0.93; p = 0.036). We showed that perioperative magnesium sulfate administration was associated with a lower rate of PPP one year after TKA. Our results suggest that magnesium sulfate administered perioperatively is effective for the alleviation of acute and chronic pain after surgery.

Background: Remimazolam is a novel short-acting benzodiazepine. This study compared the effects of remimazolam and propofol on cognitive function in adult patients after surgery or other procedures.Methods: We searched electronic databases, including PubMed, Embase, CENTRAL, Web of Science, and Scopus, for relevant studies. The primary outcome was the proportion of participants who experienced delirium or impaired cognitive function postoperatively. Secondary outcomes included the incidence of hypotension, bradycardia, and postoperative nausea and vomiting. We estimated the odds ratios (OR) and mean differences (MD) with 95% CIs using a random-effects model.Results: In total, 1295 patients from 11 randomized controlled trials were included. The incidence of postoperative delirium was 8.0% in the remimazolam group and 10.4% in the propofol group that was not significantly different (OR: 0.74, 95% CI [0.39–1.42], P = 0.369, I2 = 32%). More favorable cognitive function, as assessed using the Mini-Mental State Examination, was observed in the remimazolam group compared to the propofol group (MD: 1.06, 95% CI [0.32–1.80], P = 0.005, I2 = 89%). Remimazolam lowered the incidence of hypotension (OR: 0.28, 95% CI [0.21–0.37], P = 0.000, I2 = 0%) compared to propofol.Conclusions: Remimazolam did not increase the risk of postoperative delirium and maintained cognitive function well, providing hemodynamic stability during surgery compared to propofol.