Regional Anesthesia and Pain Medicine最新文献

{"title":"Navigating current controversies in radiofrequency ablation of the genicular nerves for chronic knee pain in osteoarthritis: a daring discourse.","authors":"Nuno Ferreira-Silva, Guilherme Ferreira-Dos-Santos, Tomás Cuñat, Tomas Ribeiro-da-Silva, Philip Peng","doi":"10.1136/rapm-2025-106518","DOIUrl":"10.1136/rapm-2025-106518","url":null,"abstract":"<p><p>Chronic knee joint pain affects millions worldwide, with radiofrequency ablation (RFA) of genicular nerves emerging as a potential treatment in the last 15 years. Despite its growing popularity, with studies demonstrating its efficacy in pain reduction for up to 12 months, recent randomized controlled trials have questioned the efficacy of RFA. Discrepancies in study results may partially be explained by the heterogeneity of patient selection and technical protocols.This daring discourse aims to explore and critically analyze the ongoing debates surrounding RFA of the genicular nerves, addressing key controversies, namely: (1) Is there a role for performing prognostic blocks prior to RFA?; (2) What are the optimal target sites for final cannulae placement for the classical targets?; (3) Which and how many nerves should be targeted in RFA procedures?; (4) What are the comparative benefits of using ultrasound versus fluoroscopy guidance, and whether a combined technique may be advantageous?; (5) Is there a potential role for pulsed radiofrequency of the genicular nerves?; (6) Should genicular nerve RFA be performed after total knee arthroplasty?Through this in-depth discussion, we aim to guide pain medicine clinicians in informed decision-making and encourage further research in this field.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1166-1177"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144644156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feeding following cleft palate surgery: a prospective randomized clinical trial comparing suprazygomatic maxillary nerve block and greater palatine nerve block.","authors":"Vrushali Ponde, Hanna Smeds, Parit Ladani, Jacob Karlsson, Per-Arne Lonnqvist, Srinitya Kollu","doi":"10.1136/rapm-2025-106743","DOIUrl":"10.1136/rapm-2025-106743","url":null,"abstract":"<p><strong>Introduction: </strong>In the context of cleft-lip and palate surgery, both suprazygomatic maxillary nerve blocks (SZMNB) and greater palatine nerve blocks (GPNB) have been shown to provide improved postoperative pain relief. In this context, both pain relief and early postoperative feeding are of great importance. However, these two techniques have so far not been properly compared with regard to these characteristics.</p><p><strong>Methods: </strong>Children 1-10 years of age undergoing palate surgery were randomized to either SZMNB or GPNB. Primary aim was early (0-24 hour) postoperative feeding (%) in relation to full normal oral feeding. Secondary aims were postoperative pain scores and need for rescue paracetamol administration (pain score >4).</p><p><strong>Results: </strong>30 patients were randomized to each study group (no missing data). Patients in group SZMNB displayed significantly better oral feeding during the first 24 hours compared with the GPNB group (median 80% [range 70-90%] and median 60% [range 40-70], respectively; p<0.00001). Group SZMNB did also show lower pain scores during 0-12 hour postoperatively (p<0.05-0.001) and fewer patients needed rescue paracetamol (p<0.05) compared with the GPNB group.</p><p><strong>Conclusion: </strong>The use of bilateral suprazygomatic maxillary nerve blocks was found superior to greater palatine blocks with regard to the amount of postoperative feeding in children undergoing palate surgery. Bilateral suprazygomatic maxillary nerve blocks were also associated with lower postoperative pain scores during the first 12 hours postoperative, further reflected by the reduced need for postoperative rescue administration of intravenous paracetamol.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1161-1165"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145042222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caudal versus penile block and urethrocutaneous fistula formation following hypospadias repair in children <2 years: a multicenter randomized clinical trial.","authors":"Andreas Taenzer, Tessa N Mandler, Alexia Gagliardi, Megan A Brockel, Vijaya Vemulakonda, Sophie R Pestieau, David M Polaner","doi":"10.1136/rapm-2026-108027","DOIUrl":"10.1136/rapm-2026-108027","url":null,"abstract":"<p><strong>Background: </strong>Retrospective studies report conflicting associations between caudal block and urethrocutaneous fistula (UCF) formation after hypospadias repair, often without control for hypospadias severity. Our multicenter randomized, non-inferiority trial compared UCF incidence following caudal versus penile block for single-stage hypospadias surgery.</p><p><strong>Methods: </strong>Children ≤2 years undergoing primary single-stage midshaft or distal hypospadias repair at 16 Pediatric Regional Anesthesia Network centers were randomized to caudal (group C) or penile block (group P) with general anesthesia. The primary outcome was UCF formation within 3 postoperative months. Secondary outcomes included perioperative opioid administration, and postoperative pain scores (Face, Legs, Activity, Cry and Consolability (FLACC)).</p><p><strong>Results: </strong>Of 210 subjects, 161 (76.6%) completed 3-month follow-up (group C: N=79; group P: N=82). UCF occurred in 7/79 (8.9%) group C and 6/82 (7.3%) group P patients (RR=0.98; 95% CI (0.35 to 2.76); p=0.9). Proximal meatal position was associated with increased UCF risk (RR=2.8; 95% CI (1.48 to 5.30); p=0.002). Group C received less intraoperative (33% vs 56%, p<0.001) and rescue opioids (4.9% vs 15.7%; p=0.01) and had lower mean postanesthesia care unit (PACU) FLACC scores (0.49±1.34 vs 1.14±2.3; p=0.03).</p><p><strong>Conclusion: </strong>In this early terminated randomized trial, no statistically significant difference in UCF formation was observed between caudal and penile blocks. Caudal block was associated with reduced perioperative opioids and lower pain scores. However, incomplete enrollment, loss to follow-up and wide CIs limit precision, and clinically important differences between the techniques cannot be excluded. The findings should be considered exploratory and may inform future trials and evidence generation.</p><p><strong>Trial registration number: </strong>NCT02861950.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1112-1117"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148946276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Augmented reality-guided craniofacial and airway nerve block training for anesthesiology residents.","authors":"David Zheng, Cheyenne N Mercer, Nathan Lau, John Francis Ryan, Amir Moradi, Steven Howe, Preetham Suresh, Geoffroy Noel","doi":"10.1136/rapm-2025-106776","DOIUrl":"10.1136/rapm-2025-106776","url":null,"abstract":"<p><p>The acquisition of craniofacial and airway nerve block (ANB) skills is hindered by the complex anatomy involved, reliance on landmark-guided techniques, and the absence of simulation-based training tools. Augmented reality offers a promising platform for procedural training by providing real-time visual feedback, yet its potential to improve accuracy in ANBs has not been evaluated. This exploratory study assessed the feasibility of AR guidance for improving nerve block performance among anesthesiology faculty and residents.20 participants performed infraorbital, inferior alveolar, superior laryngeal, and glossopharyngeal nerve blocks with and without AR guidance using volumetric Digital Imaging and Communications in Medicine (DICOM) reconstructions superimposed on body donor heads via Hololens headset, from Microsoft Corporation and SurgicalAR software from Medivis. AR guidance included a localizer instrument for real-time tracking of a physical needle along a premapped virtual needle path. Performance was assessed by dissection-based accuracy (proximity of methylene blue to the nerve) and procedure time.Overall clinical acceptability was similar between AR and non-AR conditions (65.0% vs 55.0%, McNemar's p=0.754). There were no differences in performance when stratified by level of training (McNemar p=0.219 for residents; McNemar p=0.625 for faculty). However, AR significantly increased procedure time (overall 49.9±8.4 vs 14.5±2.6 s, Wilcoxon p<0.001) and time increases were consistent across training levels (faculty: +34.9 s, p=0.016; residents: +36.0 s, p=0.062). Additionally, there was no difference in nerve block success or procedure length between an overlay mode with the DICOM superimposed onto the body donor and a detached mode with the DICOM floating above or next to the body donor.In this small, exploratory study, AR did not significantly impact the rates of clinically acceptable nerve blocks when performed by faculty or resident anesthesiologists; however, AR significantly increased the amount of time required to perform the procedures. This proof-of-concept study successfully demonstrated the feasibility of using AR to learn and/or perform various craniofacial and ANBs using commercially available technology.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1178-1183"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145139351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clinical utility of randomized controlled trials of regional anesthesia for lower-extremity surgery: a systematic review.","authors":"Danielle Waller, Josh Saurino, Adam Khan, Taylor Gardner, Alec Young, Chance Bratten, Eli Paul, Bryan Dunford, Will Roberts, Aaron Relic, Alicia I Ford, Matt Vassar","doi":"10.1136/rapm-2025-107065","DOIUrl":"10.1136/rapm-2025-107065","url":null,"abstract":"<p><strong>Background: </strong>Regional anesthesia (RA) is central to multimodal analgesia, yet many supporting randomized controlled trials (RCTs) may lack the rigor needed for evidence-based block selection.</p><p><strong>Objectives: </strong>To evaluate the clinical usefulness and transparency of RCTs investigating RA interventions for lower extremity surgeries, using the van 't Hooft <i>et al</i> framework.</p><p><strong>Methods: </strong>Embase/MEDLINE were searched for RCTs (2014-2024) examining RA interventions for lower-extremity surgery. Data were extracted in duplicate using clinical-utility and transparency criteria. Analyses included descriptive statistics, linear regression for temporal trends, Pearson correlation, and multivariable regression to identify predictors of usefulness.</p><p><strong>Results: </strong>Among 248 RCTs, patient-centeredness was universal, while feasibility (77.0%) and context placement (77.4%) were common. Pragmatism (2.0%) and value-for-money analyses (0%) were rare. Transparency varied: conflicts of interest were disclosed in 88.7%, pre-registration occurred in 39.9%, public protocols in 10.1%, and raw-data sharing in 1.2%. Transparency improved over time, correlated with clinical-utility scores (r=0.32, p<0.001) and was greater in hospital-funded, self-funded, and higher-impact journals.</p><p><strong>Limitations: </strong>Usefulness scoring involves subjective judgment; non-English trials were excluded; the absence of formal risk of bias analysis limits interpretability of trial quality.</p><p><strong>Discussions/conclusions: </strong>Although transparency is improving, most trials remain insufficiently pragmatic, lack economic evaluation, and rarely share data, limiting real-world applicability. The results of this study suggest that aligning funder, journal, and collaborative expectations around open science and pragmatic design could accelerate the generation of high-utility evidence for perioperative block selection.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1221-1228"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638321/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145294320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Objective, long-term mobility data in patients with chronic pain after lumbar spine surgery treated with spinal cord stimulation-a prospective, multicenter trial.","authors":"Tobias Hallén, Kaare Meier, Jan Willem Kallewaard, Bart Billet, Lars Elzinga, Johannes Schapendonk, Eric Van den Bosch, Xander Zuidema, Kristin Lilja Eyglóardóttir, Helga Gulisano, Kliment Gatzinsky","doi":"10.1136/rapm-2025-106726","DOIUrl":"10.1136/rapm-2025-106726","url":null,"abstract":"<p><strong>Objective: </strong>Spinal cord stimulation (SCS) is a treatment option for chronic neuropathic pain conditions when conventional therapies have failed. However, objective and measurable long-term data on the effects of SCS are lacking. This study evaluates changes in objectively recorded mobility and the correlation with patient-reported outcomes in SCS-treated patients with intractable back and/or leg pain following lumbar spine surgery.</p><p><strong>Methods: </strong>Fifty patients were enrolled. Baseline mobility was recorded over 4 weeks using an external neurostimulator with a built-in accelerometer. Patients achieving ≥50% pain relief during a subsequent SCS test trial received a permanently implanted stimulator at the same site. Mobility data were extracted at 3, 6, and 12 months and compared with baseline alongside work status, medication usage, and patient-reported outcome measures.</p><p><strong>Results: </strong>Thirty-seven patients received a permanent stimulator, and 32 completed the 12 month follow-up of activity data. Time spent in mobility episodes lasting at least 30 s was 34±27 min/24 hours for SCS-patients at baseline compared with 92±51 min for healthy controls (p=0.009). Mobility increased gradually after SCS, reaching statistical significance at 12 months (p=0.045). The increase was significant in patients with predominant leg pain (35±27 to 54±32 min, p=0.011) but not in those with predominant back pain. Significant improvements were observed in working ability, medication reduction, and self-reported outcomes. Increased mobility correlated significantly with reduction in self-reported disability (p=0.044) and leg pain (p=0.046).</p><p><strong>Conclusion: </strong>The new objective data indicate that SCS has beneficial, long-term effects on mobility in patients with intractable leg pain after spine surgery.</p><p><strong>Trial registration number: </strong>NCT04710355.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1124-1132"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638309/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144610353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Buprenorphine versus full agonist opioids for acute postoperative pain management: a systematic review and meta-analysis of randomized controlled trials.","authors":"Ryan S D'Souza","doi":"10.1136/rapm-2025-106394","DOIUrl":"10.1136/rapm-2025-106394","url":null,"abstract":"","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1229"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143123030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single versus two-level superficial parasternal intercostal plane block: cadaveric evaluation of injectate spread with needle tip position on anterior surface of costal cartilage.","authors":"Jon Christensen, Matthew Ritter, Rachel Douglas, Punnose Kattil, Nirusha Lachman, William J Mauermann","doi":"10.1136/rapm-2025-106488","DOIUrl":"10.1136/rapm-2025-106488","url":null,"abstract":"<p><strong>Introduction: </strong>Superficial parasternal intercostal plane blocks have grown in clinical use for cardiac surgery as a targeted fascial plane block for median sternotomy. Despite this, there remains no consensus on technique for optimal parasternal spread of injectate. The primary objective of this cadaveric study was to evaluate parasternal spread of injectate of single versus two-level superficial parasternal intercostal plane injections with the needle tip positioned on the anterior surface of the costal cartilage.</p><p><strong>Methods: </strong>We performed 10 single-level injections at T4 and 10 two-level injections at T3 and T5 on alternating sides in 10 fresh frozen cadavers. All injections were ultrasound guided with a parasagittal ultrasound probe orientation and an in-plane needle orientation. Anatomic dissections were performed immediately following injections.</p><p><strong>Results: </strong>Parasternal spread of injectate was greater with two-level injections at T3 and T5 costal cartilages than with single-level injections at the T4 costal cartilage, with two-level injections consistently spreading to the T2-T5 intercostal spaces. Median (Q1, Q3) intercostal space spread for single-level injections was 2.0 (2.0-2.5). Median (Q1, Q3) intercostal space spread for two-level injections was 4.0 (4.0-4.375).</p><p><strong>Conclusions: </strong>Two-level injections with the needle tip located on the anterior surface of the costal cartilage resulted in improved parasternal spread compared with single-level injections.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1133-1136"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143803257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"National trends in naloxone codispensing with outpatient opioid prescriptions, 2013-2023.","authors":"Evan J Beck, Kao-Ping Chua, Vidhya Gunaseelan, Mark Bicket, Chad M Brummett, Amy Bohnert, Jennifer F Waljee","doi":"10.1136/rapm-2025-106911","DOIUrl":"10.1136/rapm-2025-106911","url":null,"abstract":"<p><strong>Background: </strong>Increasing access to naloxone, an opioid antagonist, can prevent opioid overdose among patients prescribed opioids. In 2016, the Centers for Disease Control and Prevention recommended coprescribing naloxone with opioids; however, the extent to which this guideline influenced clinical practice remains unclear. In this study, we seek to describe trends in the rate of naloxone codispensing with opioid prescriptions from 2013 to 2023.</p><p><strong>Methods: </strong>This serial cross-sectional analysis used the IQVIA Longitudinal Prescription Database, which captures 92% of dispensed US retail prescriptions, to examine opioid prescriptions dispensed to individuals aged 12 years and older between January 1, 2013 and September 30, 2023. Naloxone codispensing was defined as naloxone dispensed within 3 days of the opioid dispensing date. Subgroup analyses included high-risk opioid prescriptions, long-term opioid therapy, and prior dispensing of buprenorphine for opioid use disorder.</p><p><strong>Results: </strong>From 2013 to 2023, 1 690 391 169 opioid prescriptions were dispensed, with naloxone codispensing occurring in 3 531 421 (0.2%) cases, increasing from 0.0% in 2013 to 0.9% in 2023. Naloxone codispensing increased from 0.0% to 1.3% among high-risk prescriptions, from 0.0% to 0.7% for long-term opioid therapy, and from 0.0% to 1.8% for prior buprenorphine recipients during the study period.</p><p><strong>Conclusions: </strong>In this analysis of a national prescription dispensing database, naloxone codispensing with prescription opioids increased for 2013-2023 but remained infrequent, even among individuals at elevated risk for opioid overdose. Although these data do not capture naloxone obtained through prior prescriptions or free distribution programs, these findings emphasize the need for targeted interventions to promote naloxone codispensing. Clinician education, policy measures, and continued community outreach may help increase naloxone uptake and improve access for at-risk patients.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1144-1150"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12949550/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144884315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystallization of local anesthetic and adjuvant mixtures: a chemical analysis of the crystal precipitate composition.","authors":"Elisabeth Gasteiger, Benedikt Schwarz, Matthias Harder, Lukas Gasteiger, Matthias Rainer, Christian W Huck, Ottokar Stundner","doi":"10.1136/rapm-2025-106981","DOIUrl":"10.1136/rapm-2025-106981","url":null,"abstract":"<p><strong>Introduction: </strong>Local anesthetics are often mixed with other local anesthetics or adjuvants to enhance block duration and/or speed of onset. Recent studies described the appearance of significant microscopic crystallization in such mixtures. However, the impact of precipitation on solute concentration, as well as the chemical composition of these crystals, remained unclear.</p><p><strong>Methods: </strong>Eight commonly used mixtures of local anesthetics and adjuvants, which have previously been found to cause significant crystallization, were assessed using a high-performance liquid chromatography-ultraviolet system to detect changes in solute concentration for 800 min (13.3 hours) after admixtures. In a second step, liquid chromatography-mass spectrometry was used to investigate the composition of precipitates formed in lidocaine+sodium bicarbonate and lidocaine+ropivacaine+sodium bicarbonate mixtures.</p><p><strong>Results: </strong>The concentration of the assessed mixtures remained constant over time, indicating that precipitation did not significantly affect the concentration of local anesthetics in the mix. The precipitates appearing in lidocaine+sodium bicarbonate and lidocaine+ropivacaine+sodium bicarbonate mixtures are composed of pure local anesthetics.</p><p><strong>Discussion: </strong>Our study reveals that no effect on local anesthetic concentration in the solution was apparent. Moreover, the precipitates forming in lidocaine/ropivacaine/sodium bicarbonate mixtures are composed of pure local anesthetics. Our findings might facilitate the design of future in vivo studies assessing the behavior of local anesthetics crystals.</p>","PeriodicalId":54503,"journal":{"name":"Regional Anesthesia and Pain Medicine","volume":" ","pages":"1184-1190"},"PeriodicalIF":4.0,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145180301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}