Regional Anesthesia and Pain Medicine最新文献

Introduction: Genicular nerve blocks (GNBs) are an emerging technique that have been used as a part of multimodal analgesia for total knee arthroplasty. The efficacy of intraoperative landmark-based GNBs, a recently introduced technique, has been established. We hypothesized that it would provide non-inferior postoperative analgesia compared with periarticular infiltration (PAI) when combined with continuous adductor canal block.

Methods: This study randomized 140 patients undergoing total knee arthroplasty to receive either intraoperative landmark-based GNB (GNB group) or PAI (PAI group), with 139 completing the study. The primary outcomes were the pain scores at rest and during movement at 12 hours postoperatively on an 11-point Numerical Rating Scale; the non-inferiority margin was 1. Pain scores at additional time points, intravenous morphine consumption, time to first rescue analgesia, functional performance and muscle strength tests, and sleep disturbance were also assessed.

Results: At 12 hours postoperatively, the PAI and GNB groups had median resting pain scores of 0 (0-2) and 0 (0-2), respectively. The median difference was 0 (95% CI -0.4 to 0.4, p=1), with the 95% CI upper limit below the prespecified non-inferiority margin. The median pain score during movement was 1.5 (0-2.3) and 2 (1-3.1) in the PAI and GNB groups, respectively. The median difference was 0.9 (95% CI 0.3 to 1.6, p=0.004), failing to demonstrate non-inferiority. The GNB group had higher intravenous morphine consumption at 12 hours postoperatively and a shorter time to first rescue analgesia.

Conclusions: GNB compared with PAI provides non-inferior resting pain relief. Non-inferiority was not established for pain during movement.

Trial registration number: TCTR20220406001 (www.thaiclinicaltrials.org).

Introduction: This research endeavors to investigate the phenomenon of intraneural spread across distinct locations: subcircumneurium, extrafascicular intraneural, intrafascicular intraneural, and intraperineurium after deliberate intraneural injections across five mammalian species. The study also aims to propose determinants influencing this spread. Furthermore, the investigation strives to ascertain the optimal animal species and needle configuration for extrapolating intraneural injection outcomes to human contexts.

Methods: This study examined 60 sciatic nerves from 30 fresh and untreated cadavers of rats, rabbits, dogs, pigs, and sheep. The specimens were organized into five groups, each comprising an equal number of nerves. Histological assessments were performed on 30 nerves, involving fascicle metrics. The remaining 30 nerves underwent intentional intraneural injections, facilitated by 19G and 23G needles under ultrasound and direct visualization guidance.Heparinized erythrocytes combined with a methylene blue solution were used as a marker to analyze the extent and patterns of intraneural spread. Needle orifice measurements were obtained, and these data were overlaid onto images of both nerves and needles. This enabled a comparative evaluation of sizes and an assessment of marker diffusion.

Results: The findings indicated that sciatic nerves in rats, rabbits, and dogs were oligofascicular, characterized by larger fascicles, whereas pigs and sheep exhibited polyfascicular nerves comprised of numerous smaller fascicles. Fascicular diameters were variable across species, with dogs presenting the largest measurements. While intraneural spread was observed and documented, intrafascicular marker spreading was rare, occurring only in one rabbit specimen. Needle orifice attributes were scrutinized and visually depicted.

Conclusions: Despite the formidable challenges associated with the practical realization of intrafascicular injection, the utilization of animal models possessing monofascicular or oligofascicular nerves, such as rats, rabbits, and dogs, in conjunction with needles featuring aperture dimensions surpassing those of the fascicles, likely contributes to the compromised reliability of investigations into intraneural injection outcomes.

Introduction: Artificial intelligence and large language models (LLMs) have emerged as potentially disruptive technologies in healthcare. In this study GPT-3.5, an accessible LLM, was assessed for its accuracy and reliability in performing guideline-based evaluation of neuraxial bleeding risk in hypothetical patients on anticoagulation medication. The study also explored the impact of structured prompt guidance on the LLM's performance.

Methods: A dataset of 10 hypothetical patient stems and 26 anticoagulation profiles (260 unique combinations) was developed based on American Society of Regional Anesthesia and Pain Medicine guidelines. Five prompts were created for the LLM, ranging from minimal guidance to explicit instructions. The model's responses were compared with a "truth table" based on the guidelines. Performance metrics, including accuracy and area under the receiver operating curve (AUC), were used.

Results: Baseline performance of GPT-3.5 was slightly above chance. With detailed prompts and explicit guidelines, performance improved significantly (AUC 0.70, 95% CI (0.64 to 0.77)). Performance varied among medication classes.

Discussion: LLMs show potential for assisting in clinical decision making but rely on accurate and relevant prompts. Integration of LLMs should consider safety and privacy concerns. Further research is needed to optimize LLM performance and address complex scenarios. The tested LLM demonstrates potential in assessing neuraxial bleeding risk but relies on precise prompts. LLM integration should be approached cautiously, considering limitations. Future research should focus on optimization and understanding LLM capabilities and limitations in healthcare.

Introduction: Most Americans live in a state that has legalized cannabis as a medical treatment for pain, but it is unclear how chronic pain intensity relates to cannabis use. Our objective was to examine the association between patient-reported pain measures and cannabis among adults with chronic pain.

Methods: This cross-sectional study of a representative sample of adults reporting chronic non-cancer pain in 36 states and DC with active medical cannabis programs from March to April 2022 assessed cannabis use for chronic pain, categorized as active (within 30 days), past (>31 days), or never use (referent). Measures were pain intensity (primary) and interference, Widespread Pain Index, and number of chronic pain diagnoses.

Results: Among 1628 participants (57% female, 69% white), 352 (22%) actively used cannabis to treat chronic pain, 137 (8%) reported past cannabis use, and 1139 (70%) never used cannabis. In adjusted models, active cannabis use was associated with higher scores for pain intensity (score difference 1.03, 95% CI 0.05 to 2.02) and pain interference (score difference 1.82, 95% CI 0.99 to 2.65) compared with never use. Persons who actively used cannabis had higher Widespread Pain Index scores (score difference 0.56, 95% CI 0.26 to 0.86) and more chronic pain diagnoses (difference 0.45, 95% CI 0.06 to 0.83).

Conclusion: People with chronic non-cancer pain who used cannabis for pain reported non-clinically meaningful worse pain measures and greater burden of chronic pain conditions than their counterparts who never used cannabis. Alternatively, those with worse pain and greater burden of pain appear more likely to use cannabis.

Over time, the focus of evidence-based acute pain medicine has shifted, from a focus on drugs and interventions (characterized by numbers needed to treat), to an appreciation of procedure-specific factors (characterized by guidelines and meta-analyses), and now anesthesiologists face the challenge to integrate our current approach with the concept of precision medicine. Psychometric and biopsychosocial markers can potentially guide clinicians on who may need more aggressive perioperative pain management, or who would respond particularly well to a given analgesic intervention. The challenge will be to identify an easily assessable set of parameters that will guide perioperative physicians in tailoring the analgesic strategy to procedure and patient.

Background: This study assessed the effect of perineural dexamethasone on block duration, opioid requirement, blood glucose levels, and stress response to surgery as measured by the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR), following pediatric foot and ankle surgery.

Methods: In this parallel, double-blinded randomized controlled trial, 90 children (ages 2-5 years, >5 kg) scheduled for foot or ankle surgery under spinal anesthesia with ultrasound-guided single-shot popliteal sciatic nerve block were randomized into 3 groups: 0.5% ropivacaine with saline (control), 0.5% ropivacaine plus dexamethasone 0.1 mg/kg (DEX0.1), and 0.5% ropivacaine plus dexamethasone 0.05 mg/kg (DEX0.05). Primary outcome was the time to first rescue opioid analgesia. Secondary outcomes included motor block duration, pain scores, NLR, PLR, and blood glucose levels.

Results: Time to first rescue opioid analgesia was significantly longer in the DEX0.1 group compared with the DEX0.05 group (18.4 hours, SD 2.6 hours vs 16 hours, SD 2.8 hours), with a mean difference of 2.2 hours (95% CI 0.7 to 3.6), p<0.01; and the control group (8.5 hours, SD 1.5 hours), with a mean difference of -9.9 (95% CI -11.4 to -8.4), p<0.001. Motor block was significantly longer in the DEX0.1 group (17.3 hours, SD 2.5 hours) compared with the DEX0.05 (15.2 hours, SD 2.7 hours; p<0.01) and control groups (7.8±1.1, p<0.001). Total opioid consumption was significantly lower in the DEX0.1 group compared with the control group (p=0.01). NLR, PLR, and glucose levels did not differ significantly between the groups at baseline, 24 hours, and 48 hours post surgery.

Conclusions: Perineural dexamethasone significantly prolonged postoperative motor block duration and did not influence blood glucose, NLR, or PLR levels.

Trial registration number: NCT06086418.

Background: Needle trauma has been associated with peripheral nerve injury and neurological dysfunction. However, inadvertent needle puncture is frequent while postblock dysfunction is rare. We conducted a cadaveric study to evaluate the association between needle puncture and fascicular injury.

Methods: Five median and five ulnar (isolated) nerves were obtained from fresh human cadavers. Four different needles were used for the transfixing punctures: A 30° beveled (22G) nerve block needle, and 15° beveled (22G, 25G and 27G) Quincke spinal block needles. 10 transfixing punctures were made with each needle type on each nerve (40 punctures per nerve). Samples were then immersed in 5% formaldehyde solution for 30 days. Perpendicular cross-sections of the punctured segments were obtained. Samples were embedded in paraffin and analyzed under light microscopy with H&E staining. On each slice, the following variables were obtained: ratio of fascicular/epineurial tissue, the number of fascicles per nerve and the number of injured fascicles.

Results: A total of 400 punctures were made (200 median and 200 ulnar) and 144 histological nerve sections analyzed (74 median and 70 ulnar). The median number of fascicles per section was 16 (range 7-23) and 17 (range 8-27) with a fascicular/epineural tissue ratio of 45% (range 35%-52%) and 44% (range 39%-54%) for median and ulnar, respectively. Three fascicular injuries were identified: one in ulnar and two in median. All injuries were caused by a 15° beveled needle, the ulnar with a 22G and the median with a 22G and a 27G.

Conclusions: Fascicular injury is rare following needle transfixion. Needle injury alone is unlikely to explain postblock neurological dysfunction.