The Ultrasound-Guided Retroclavicular Block
Bibliographic record
Abstract
BACKGROUND AND OBJECTIVES: The aim of this feasibility study was to determine the success rate (sensory and surgical) of the novel retroclavicular block and to thoroughly describe the technique. In addition, needle tip and shaft visibility, needling time, procedural discomfort, motor block success rate, patient satisfaction at 48-hour follow-up, and complications were also recorded. METHODS: Fifty patients scheduled for distal upper limb surgery received an in-plane, single-shot, ultrasound-guided retroclavicular block with 40 mL of mepivacaine 1.5% with epinephrine 2.5 μg/mL. Block success was defined as a sensory score of 10/10 for the 5 nerves supplying the distal upper limb at 30 minutes. Surgical success, needle visibility, needling time, axillary artery depth, motor block rate, patient discomfort with technique, satisfaction at 48 hours, and complications were also recorded. All blocks were video-recorded and timed for further independent assessment. A chest x-ray was obtained before discharge. RESULTS: Forty-five patients had a total sensory score of 10/10 at 30 minutes (90% success rate). Surgical success rate was 96%. Mean needling time was 3.77 minutes (25th-75th percentiles, 2.90-6.53 minutes) with a mean axillary artery depth of 3.1 ± 0.7 cm. Procedure-related discomfort (mean visual analog scale, 1.9 ± 1.2) was low. Mean 48-hour patient satisfaction rate (9.2 ± 1.1), mean needle tip (Likert scale, 3.0 ± 0.9), and shaft visibility (3.9 ± 0.9) were high. One vascular puncture and two transient paresthesias were recorded. No pneumothorax was revealed by chest x-ray. CONCLUSIONS: In this study, the novel retroclavicular block offered a quick, safe, and reliable alternative for distal arm block. Further studies, comparing this approach with the classic infraclavicular block, are required to validate its efficacy, safety, and reliability.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".