Ultrasound with neurostimulation compared with ultrasound guidance alone for lumbar plexus block
Bibliographic record
Abstract
BACKGROUND: Ultrasound-guided lumbar plexus blocks usually require confirmatory neurostimulation. A simpler alternative is to inject local anaesthetic inside the posteromedial quadrant of the psoas muscle under ultrasound guidance. OBJECTIVE: We hypothesised that both techniques would result in similar total anaesthesia time, defined as the sum of performance and onset time. DESIGN: A randomised, observer-blinded, equivalence trial. SETTING: Ramathibodi Hospital and Maharaj Nakorn Chiang Mai Hospital (Thailand) from 12 May 2016 to 10 January 2017. PATIENTS: A total of 110 patients undergoing total hip or knee arthroplasty, who required lumbar plexus block for postoperative analgesia. INTERVENTION: In the combined ultrasonography-neurostimulation group, quadriceps-evoked motor response was sought at a current between 0.2 and 0.8 mA prior to local anaesthetic injection (30 ml of lidocaine 1% and levobupivacaine 0.25% with epinephrine 5 μg ml and 5 mg of dexamethasone). In the ultrasound guidance alone group, local anaesthetic was simply injected inside the posteromedial quadrant of the psoas muscle. MAIN OUTCOMES MEASURES: We measured the total anaesthesia time, the success rate (at 30 min), the number of needle passes, block-related pain, cumulative opioid consumption (at 24 h) and adverse events (vascular puncture, paraesthesia, local anaesthetic spread to the epidural space). The equivalence margin was 7.4 min. RESULTS: Compared with ultrasound guidance alone, combined ultrasonography-neurostimulation resulted in decreased mean (±SD) total anaesthesia time [15.3 (±6.5) vs. 20.1 (±9.0) min; mean difference, -4.8; 95% confidence interval, -8.1 to -1.9; P = 0.005] and mean (±SD) onset time [10.2 (±5.6) vs. 15.5 (±9.0) min; P = 0.004). No inter-group differences were observed in terms of success rate, performance time, number of needle passes, block-related pain, opioid consumption or adverse events. CONCLUSION: Although the ultrasonography-neurostimulation technique results in a shorter total anaesthesia time compared with ultrasound guidance alone, this difference falls within our accepted equivalence margin (±7.4 min). TRIAL REGISTRATION: www.clinicaltrials in the (Study ID: TCTR20160427003).
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".