Respiratory safety and analgesic efficacy of ultrasound-guided nerve block techniques for shoulder surgery: a systematic review and Bayesian network meta-analysis

Abstract Background The ISB remains the reference standard for shoulder surgical analgesia, but its high incidence of HDP limits use in patients with compromised respiratory function. No study has simultaneously ranked all available techniques across both safety and efficacy domains. Methods This network meta-analysis compared HDP incidence and 24-hour postoperative pain among six ultrasound-guided nerve block techniques: ISB, CCB, STB, SCB, SSNB, and ShB. Six databases and one trial register were searched from inception to December 31, 2025, with an updated search on 13 August 2026. RCTs comparing at least two techniques in adults undergoing elective shoulder surgery were included. Bayesian random-effects consistency models were fitted using MCMC sampling, and SUCRA values calculated for treatment ranking. Evidence quality was assessed using GRADE-CINeMA. Results Thirty-six RCTs involving 2,767 patients were included. Compared with ISB, CCB (OR < 0.01, 95% CrI: <0.01–0.02), SCB (OR 0.03, 95% CrI: <0.01–0.30), SSNB (OR 0.03, 95% CrI: <0.01–0.48), and STB (OR 0.04, 95% CrI: 0.01–0.22) significantly reduced HDP incidence. CCB had the highest safety ranking (SUCRA = 92.2%). For 24-hour pain scores, no alternative technique differed significantly from ISB (MD range: −0.53 to + 0.10), with ShB ranking highest for analgesia (SUCRA = 80.7%). Clustered ranking analysis identified ShB and SCB as balanced options offering both respiratory safety and analgesic efficacy; because the credible intervals for all pairwise pain comparisons overlapped, these rankings indicate ranking probability rather than demonstrated superiority. Conclusions Phrenic nerve-sparing alternatives showed no significant difference in 24-hour postoperative analgesia compared with ISB. CCB, SCB, SSNB, and STB significantly reduced HDP risk, while ShB showed a non-significant trend toward reduction. CCB was associated with the lowest ranked risk of HDP, although the certainty of evidence was low. ShB and SCB ranked favourably on both dimensions, but no pairwise difference in 24-hour pain reached statistical significance, and these rankings should therefore be regarded as hypothesis-generating. Technique selection should be individualized according to patient respiratory risk and clinical priorities.