Peripheral Nerve Blocks for Ambulatory Shoulder Surgery
Bibliographic record
Abstract
BACKGROUND: Nerve blocks improve early pain after ambulatory shoulder surgery; impact on postdischarge outcomes is poorly described. Our objective was to measure the association between nerve blocks and health system outcomes after ambulatory shoulder surgery. METHODS: We conducted a population-based cohort study using linked administrative data from 118 hospitals in Ontario, Canada. Adults having elective ambulatory shoulder surgery (open or arthroscopic) from April 1, 2009, to December 31, 2016, were included. After validation of physician billing codes to identify nerve blocks, we used multilevel, multivariable regression to estimate the association of nerve blocks with a composite of unplanned admissions, emergency department visits, readmissions or death within 7 days of surgery (primary outcome) and healthcare costs (secondary outcome). Neurology consultations and nerve conduction studies were measured as safety indicators. RESULTS: We included 59,644 patients; blocks were placed in 31,073 (52.1%). Billing codes accurately identified blocks (positive likelihood ratio 16.83, negative likelihood ratio 0.03). The composite outcome was not significantly different in patients with a block compared with those without (2,808 [9.0%] vs. 3,424 [12.0%]; adjusted odds ratio 0.96; 95% CI 0.89 to 1.03; P = 0.243). Healthcare costs were greater with a block (adjusted ratio of means 1.06; 95% CI 1.02 to 1.10; absolute increase $325; 95% CI $316 to $333; P = 0.005). Prespecified sensitivity analyses supported these results. Safety indicators were not different between groups. CONCLUSIONS: In ambulatory shoulder surgery, nerve blocks were not associated with a significant difference in adverse postoperative outcomes. Costs were statistically higher with a block, but this increase is not likely clinically relevant.
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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 | 0.000 | 0.000 |
| 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 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".