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.
This randomized, double-blinded, parallel-group trial compares the effect of three ultrasound-guided regional anesthesia techniques on diaphragmatic function in elective shoulder surgery. The interscalene block (ISB), the gold standard, frequently causes phrenic nerve paralysis and hemi-diaphragmatic paresis. The suprascapular (SSNB) and costoclavicular (CCB) blocks preserve analgesia while sparing the phrenic nerve, but direct comparative data among all three are limited. Seventy-five ASA I-II patients aged 18-70 scheduled for elective shoulder surgery will be randomized 1:1:1 (25 per group) using computer-generated allocation with sealed opaque envelopes. ISB: 10 mL 0.25% bupivacaine with dexmedetomidine 0.5 µg/kg; SSNB: 10 mL of the same mixture; CCB: 20 mL of the same mixture. All blocks are ultrasound-guided and performed before a standardised general anaesthetic. Diaphragmatic excursion is measured by M-mode ultrasound of both hemidiaphragms at baseline (pre-induction), 30 minutes after the block, and in the PACU at a train-of-four ratio ≥0.9. Hemi-diaphragmatic paresis is graded as Complete (\>75% reduction or paradoxical movement), Partial (25-75%), or Normal (0-25%). The primary outcome is its incidence. Secondary outcomes include VAS pain at rest and movement (1, 3, 6, 12, 24 h), analgesic consumption, time to first rescue analgesia, block performance time, complications, and patient satisfaction.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
75
Ultrasound-guided interscalene brachial plexus block performed \~1 hour before surgery. With the patient supine and head rotated contralaterally, a high-frequency linear transducer identifies the C5-C6 roots between the anterior and middle scalene muscles. Using an in-plane technique, 10 mL of 0.25% bupivacaine combined with dexmedetomidine 0.5 µg/kg is injected with frequent aspiration.
Ultrasound-guided suprascapular nerve block performed \~1 hour before surgery. A linear high-frequency probe in the supraclavicular region identifies the suprascapular nerve. A 22-gauge echogenic needle is advanced in-plane to the nerve proximal to the transverse scapular ligament, and 10 mL of 0.25% bupivacaine combined with dexmedetomidine 0.5 µg/kg is injected under real-time ultrasound, confirming circumferential spread.
Ultrasound-guided costoclavicular brachial plexus block performed \~1 hour before surgery. With the operative arm abducted \~60°, a linear probe inferior to the mid-clavicle visualizes the three brachial plexus cords lateral to the axillary artery. An echogenic needle is advanced in-plane into the interfascial plane, and 20 mL of 0.25% bupivacaine combined with dexmedetomidine 0.5 µg/kg is injected with aspiration and ultrasound confirmation of homogeneous spread.
Incidence of hemi-diaphragmatic paresis
Incidence of hemi-diaphragmatic paresis assessed by M-mode ultrasound measurement of diaphragmatic excursion, comparing post-block values to the pre-induction baseline. Hemi-diaphragmatic paresis is defined as a \>75% reduction in diaphragmatic excursion from baseline or paradoxical diaphragmatic movement (complete paresis); a 25-75% reduction is classified as partial paresis. Measured in the PACU after recovery of muscle power (train-of-four ratio ≥0.9). Reported as the number/percentage of participants with hemi-diaphragmatic paresis in each group.
Time frame: From pre-induction baseline to PACU assessment at train-of-four ratio ≥0.9 (up to approximately 24 hours after the block
Postoperative pain score at rest (static VAS)
Pain intensity at rest was measured on a visual analogue scale (VAS), where 0 = no pain and 10 = worst imaginable pain.
Time frame: At 1, 3, 6, 12, and 24 hours postoperatively
Patient satisfaction
Overall satisfaction with the procedure and postoperative analgesia, assessed on a 5-point scale (very satisfied, satisfied, neutral, dissatisfied, very dissatisfied).
Time frame: 24 hours postoperatively
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