A Prospective Validation of Biplanar Ultrasound Imaging for C5-C6 Cervical Medial Branch Blocks
Bibliographic record
Abstract
BACKGROUND: Ultrasound (US) guidance offers an alternative to fluoroscopy for medial branch blocks of the upper cervical spine, but it may be less accurate for blocks at the C5 and C6 levels. We hypothesized that a modified technique using biplanar US imaging would facilitate level identification and provide greater accuracy for the lower cervical spine. METHODS: Forty patients with chronic neck pain underwent US-guided blocks of the C5 and C6 medial branches. For each level, 0.3 mL of a local anesthetic/iodinated contrast mixture was injected. Posterolateral in-plane needle placement was carried out in a transverse view, and the position of the needle tip was verified in the coronal plane using the C7 transverse process as a sonographic landmark. Contrast distribution, as assessed by a blinded observer on anteroposterior and lateral x-ray views, constituted the primary outcome. Secondary outcomes were performance time and pain relief 30 minutes after the blocks. RESULTS: One hundred percent and 97.5% of C5 and C6 levels, respectively, demonstrated appropriate contrast distribution. The C7 transverse process was readily identified in the coronal plane in all but 2 subjects. Performance time was 248.8 ± 82.7 seconds; the mean percentage of relief provided by the blocks was 76.9% ± 25.5%. In 30% of patients, a blood vessel was visualized crossing the C6 articular pillar and successfully avoided during needle insertion. CONCLUSIONS: Ultrasound guidance using a biplanar approach is a reliable imaging modality for C5 and C6 medial branch blocks.
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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 | 0.006 | 0.020 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".