Cervical Medial Branch Block
Bibliographic record
Abstract
BACKGROUND: Cervical medial branch blocks are commonly performed for the diagnosis and treatment of head, neck, and shoulder pain. Intermittent fluoroscopy is widely used for needle positioning and visualization of contrast distribution before medication injection. The purpose of this study was to examine the use of ultrasound as an alternative imaging technique to block the third occipital nerve and the C3 to C6 medial branches. METHODS: The study involved 2 phases with a total of 53 patients. The purpose of phase 1 was to assess the reliability of needle positioning using an ultrasound target corresponding to the middle of the bony contour of the articular pillar. Twenty patients undergoing 46 cervical medial branch blocks between C3 and C6 were recruited, and the needle tip position was graded on a 3-point scale based on its proximity to the centroid on lateral radiograph. In phase 2, 50 patients undergoing 163 levels were recruited. Using ultrasound guidance, each of the targeted levels was injected with 0.3 mL of a 1:1 mixture of local anesthetic and contrast agent. A blinded assessor reviewed contrast distribution in the anteroposterior and lateral radiograph views. RESULTS: In phase 1, all needle tips were positioned on the articular pillars; furthermore, 80.1% were located in the middle 2 quarters of the latter. In phase 2, the contrast was found to cover the appropriate level in 94.5% of cases, and no complications were noted. The incidence of aberrant spread to adjacent levels (13.5%) was similar to that reported with fluoroscopy. CONCLUSIONS: Ultrasound guidance offers a reliable alternative to fluoroscopy for third occipital nerve and C3-C6 cervical medial branch blocks. Further studies are required to validate the clinical efficacy of our technique.
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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 | 0.003 | 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) | 0.001 | 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 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".