Regional analgesia techniques for postoperative pain after breast cancer surgery: a network meta-analysis
Bibliographic record
Abstract
RATIONALE: Postoperative pain is an important outcome for individuals undergoing breast cancer surgery. Regional analgesia techniques are considered integral to postoperative pain management, but are not without risks. OBJECTIVES: To assess the analgesic benefits and harms of different regional analgesia techniques in women undergoing breast cancer surgery. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, CINAHL, Scopus, and Web of Science from inception to 6 June 2023 without restrictions on language, publication year, or publication status. ELIGIBILITY CRITERIA: We included randomised controlled trials (RCTs) comparing two or three of the following regional analgesia techniques in women undergoing breast cancer surgery: paravertebral block (PVB), erector spinae plane block (ESPB), pectoral nerve block (PEC), and serratus anterior plane block (SAPB). OUTCOMES: Our critical outcomes were postoperative pain (rated on a visual analogue scale (VAS) or numeric rating scale (NRS) of 0-10) and rates of regional analgesia-related complications. Our important outcomes were quality of recovery, time to first analgesic request, postoperative opioid and nonsteroidal anti-inflammatory drug (NSAID) use, and postoperative nausea and vomiting (PONV). RISK OF BIAS: We used the Cochrane risk of bias tool (RoB 2) to assess risk of bias. SYNTHESIS METHODS: We conducted network meta-analyses (NMAs) using multivariate frequentist random-effects models to calculate mean differences (MDs), standardised mean differences (SMDs), or risk ratios (RRs), each with its 95% confidence interval (CI). We used CINeMA to rate the certainty of evidence. We only included studies with an overall low risk of bias in the primary analysis. For postoperative pain, we considered one point difference as the minimal clinically important difference (MCID). INCLUDED STUDIES: We included 39 RCTs with a total of 2348 participants. The studies were conducted between 2013 and 2023 in Egypt, India, Turkey, China, Japan, USA, and Thailand. Most used single-shot long-acting anaesthetics administered with ultrasound guidance. In 35 studies, the surgery was modified radical mastectomy. All studies performed surgery under general anaesthesia in the hospital. Our primary analysis for postoperative pain included 16 studies. SYNTHESIS OF RESULTS: = 0%; very low-certainty evidence), although the evidence from both analyses is very uncertain. Complications Three studies (170 participants) recorded complications, but there were no reported events of block failure, local anaesthetic systemic toxicity, hypotension, nerve damage, intraneural injection, accidental vascular puncture, bleeding at puncture site, infection, or pneumothorax. Certainty of evidence We frequently downgraded the certainty of the evidence for imprecision due to small sample sizes and wide CIs, particularly for complications and analgesic use. Heterogeneity also affected certain pain outcomes. Limited data availability further reduced certainty, with outcomes based on one or two studies rated as very low. AUTHORS' CONCLUSIONS: Overall, the regional analgesia techniques included in our NMAs seem comparable in reducing postoperative pain and rates of complications. FUNDING: This Cochrane review had no dedicated funding. REGISTRATION: Protocol (2022): doi.org/10.1002/14651858.CD014818.
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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 | 0.037 | 0.092 |
| Meta-epidemiology (narrow) | 0.003 | 0.001 |
| Meta-epidemiology (broad) | 0.014 | 0.036 |
| Bibliometrics | 0.009 | 0.008 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.004 | 0.003 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 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".