Comparative Evaluation of Diaphragmatic Function Following Interscalene, Anterior Suprascapular, and Costoclavicular Nerve Blocks in Shoulder Surgery

Shoulder surgery causes significant postoperative pain, and ultrasound-guided regional anesthesia is central to its management. The interscalene block (ISB) is the gold standard but frequently causes phrenic nerve paralysis and hemi-diaphragmatic paresis, limiting its use in patients with reduced pulmonary reserve. The suprascapular (SSNB) and costoclavicular (CCB) blocks are proposed diaphragm-sparing alternatives, but data directly comparing all three are limited. This randomised, double-blinded trial will compare the incidence of hemi-diaphragmatic paresis among ultrasound-guided ISB, SSNB, and CCB in elective shoulder surgery. Seventy-five ASA I-II patients aged 18-70 will be allocated 1:1:1 to one block. The primary outcome is the incidence of hemi-diaphragmatic paresis, measured by ultrasound diaphragmatic excursion before induction and after recovery in the PACU. Secondary outcomes include postoperative pain, analgesic consumption, and patient satisfaction. The investigators hypothesise that SSNB and CCB will cause less hemidiaphragmatic paresis than ISB while providing comparable analgesia.