Background <p>Arthroscopic rotator cuff repair (ARCR) is associated with clinically relevant postoperative pain. The interscalene brachial plexus block (ISB) remains a benchmark regional anesthesia technique, but its use is limited by frequent hemidiaphragmatic paralysis (HDP) after phrenic nerve involvement. Diaphragm-sparing nerve blocks (DSNBs) have therefore been proposed to preserve respiratory function while maintaining clinically acceptable analgesia.</p> Methods <p>A systematic review was conducted according to PRISMA principles. PubMed, Scopus, and the Cochrane Library were searched for studies published from January 1, 2010 to May 1, 2025. The revised synthesis stratified the evidence by study design: randomized controlled trials were considered the primary evidence base, observational studies were supportive, and prior systematic reviews, meta-analyses, guidelines, and narrative reviews were used only for contextual interpretation and were not double-counted as clinical study units. Outcomes were standardized by time point where possible (early, 24&#xa0;h, and 48&#xa0;h pain), opioid reporting in morphine milligram equivalents (MME) when extractable, and HDP as the primary respiratory safety outcome. Risk of bias was assessed using RoB 2 for randomized trials and MINORS for non-randomized studies. Certainty of evidence was summarized using GRADE.</p> Results <p>Thirty-six publications were retained for synthesis. Compared with conventional ISB, DSNBs consistently reduced HDP, but the certainty and clinical trade-offs differed between techniques. Superior trunk block (STB) showed the most consistent balance between analgesia and respiratory preservation; evidence suggests analgesia broadly comparable to ISB at clinically relevant time points, although formal non-inferiority was not established across the entire evidence base. Posterior suprascapular nerve block combined with axillary nerve block (SSNB + AXNB) provided the greatest anatomic separation from the phrenic nerve and may be preferable in patients with severe pulmonary risk, at the cost of potentially less intense early analgesia in some studies. Anterior SSNB was considered separately because its anatomy and respiratory implications differ from posterior shoulder blocks. Costoclavicular, infraclavicular-suprascapular, and supraclavicular approaches may reduce HDP compared with ISB, but the available evidence is less mature and technique-specific complications require attention.</p> Conclusions <p>Current evidence supports DSNBs as clinically useful alternatives to conventional ISB after ARCR, especially when respiratory safety is a priority. The strongest recommendation is not a single universal block, but a risk-adapted framework based on pulmonary reserve, expected surgical pain, ultrasound availability, and operator expertise. Conclusions regarding comparative analgesic equivalence should remain cautious because outcome definitions, time points, local anesthetic regimens, and study quality are heterogeneous.</p>