A Phase 4 interventional study of Dexamethasone (IV) and Single-shot interscalene brachial plexus block in Pain, Postoperative, Rebound Pain and Shoulder Injuries, sponsored by Seoul National University Hospital. Recruiting at 1 site in South Korea. Open to participants aged 19 Years to 79 Years. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by Seoul National University Hospital · Phase 4, Interventional, and Treatment
Shoulder surgery often causes severe pain after the operation. To control this pain, doctors commonly perform a nerve block (interscalene brachial plexus block), which numbs the shoulder area. However, when the effect of a single-injection nerve block wears off, many patients experience sudden, intense pain known as "rebound pain".
One way to prevent rebound pain is to place a thin catheter near the nerves so that local anesthetic can be given continuously for a longer period (continuous nerve block). However, this method is technically demanding and can cause problems such as catheter dislodgement, infection, and inconvenience for patients. Another simpler option is to give a single-injection nerve block together with an intravenous (IV) injection of dexamethasone, a steroid medication known to prolong the effect of nerve blocks and reduce rebound pain.
The purpose of this study is to determine whether a single-injection nerve block combined with IV dexamethasone (5 mg) is not inferior to a continuous nerve block in preventing rebound pain after shoulder surgery. A total of 92 adult patients scheduled for elective shoulder surgery will be randomly assigned to one of the two groups. The main outcome is the rebound pain score, defined as the difference between the last pain score recorded in the recovery room (while the nerve block is still working) and the highest pain score reported within the first 24 hours after the nerve block. The investigators expect that the simpler single-injection method with IV dexamethasone will provide comparable pain control while avoiding the complications and inconvenience of catheter-based continuous nerve blocks.
Exclusion Criteria:
Participants receive a single-shot ultrasound-guided interscalene brachial plexus block with 0.75% ropivacaine 15-20 mL, followed by intravenous dexamethasone 5 mg administered after confirmation of successful block on arrival in the operating room. Postoperatively, an intravenous patient-controlled analgesia (PCA) pump with fentanyl (10 mcg/mL, bolus 1 mL, lockout 6 min, no basal rate) is connected. All participants receive standard multimodal analgesia (intravenous acetaminophen 1000 mg plus ibuprofen 300 mg every 8 hours).
Drug: Dexamethasone (IV) · Procedure: Single-shot interscalene brachial plexus block
Participants receive an ultrasound-guided continuous interscalene brachial plexus block: 0.75% ropivacaine 15-20 mL is injected at the interscalene level, and a perineural catheter is placed with the tip adjacent to the superior trunk. Postoperatively, a nerve block PCA (0.2% ropivacaine, basal rate 5 mL/h, bolus 3 mL, lockout 30 min) is connected via the catheter. All participants receive the same standard multimodal analgesia as the experimental arm.
Procedure: Continuous interscalene brachial plexus block
Intravenous dexamethasone 5 mg, administered as a single dose after confirmation of adequate sensory and motor block on arrival in the operating room.
Ultrasound-guided single-shot interscalene brachial plexus block performed with a 50 mm needle. 0.75% ropivacaine 15-20 mL is injected at the interscalene level. No perineural catheter is placed.
Ultrasound-guided interscalene brachial plexus block with 0.75% ropivacaine 15-20 mL, followed by placement of a perineural catheter adjacent to the superior trunk. Continuous postoperative analgesia is provided through the catheter using 0.2% ropivacaine (basal rate 5 mL/h, bolus 3 mL, lockout time 30 min) via a patient-controlled analgesia pump.
Rebound Pain Score (RPS)
Difference between the last pain score recorded in the post-anesthesia care unit (PACU) while the nerve block is still effective and the highest pain score reported within the first 24 hours after the nerve block, measured on an 11-point Numerical Rating Scale (NRS; 0 = no pain, 10 = worst pain imaginable). Higher scores indicate more severe rebound pain. Non-inferiority margin: 1.5.
Time frame: Within 24 hours after the nerve block
Postoperative pain score (NRS)
Pain intensity at rest and during movement, measured on an 11-point NRS (0 = no pain, 10 = worst pain imaginable).
Time frame: 4, 8, 12, 24, and 48 hours after surgery
Peak NRS pain score
Highest pain score reported during each period, on an 11-point NRS.
Time frame: 0-24 hours and 24-48 hours after surgery
Incidence of severe rebound pain
Proportion of participants experiencing rebound pain with NRS ≥ 7.
Time frame: Within 24 hours after the nerve block
Block duration
Time from completion of the nerve block to the first onset of pain.
Time frame: Up to 48 hours after the nerve block
Time to first rescue analgesic
Time from the end of surgery to the first administration of rescue analgesics.
Time frame: Up to 48 hours after surgery
Cumulative opioid consumption
Cumulative opioid consumption converted to oral morphine equivalents (OME), including PCA use and rescue opioids.
Time frame: 24 and 48 hours after surgery
Block performance time
Single-shot group: time from donning gloves to needle removal. Continuous group: time from donning gloves to completion of aseptic dressing.
Time frame: During the block procedure (day of surgery)
Block failure rate
Proportion of participants with inadequate sensory/motor block on arrival in the operating room requiring rescue block.
Time frame: From block completion to start of surgery (day of surgery)
Rescue block administration
Proportion of participants requiring an additional rescue block (0.75% ropivacaine 5-10 mL).
Time frame: Day of surgery
Intraoperative rescue analgesic use
Proportion of participants requiring intraoperative rescue analgesics (IV fentanyl 50-100 μg).
Time frame: During surgery
Conversion to general anesthesia
Proportion of participants requiring conversion to general anesthesia due to inadequate block or uncontrolled pain.
Time frame: During surgery
Intraoperative sedative consumption
Total dose of propofol administered for sedation during surgery.
Time frame: During surgery
Quality of Recovery-15 Korean version (QoR-15K) score
Quality of recovery assessed using the QoR-15K questionnaire (score range 0-150; higher scores indicate better recovery).
Time frame: Baseline (day before surgery) and 24 hours after surgery
Incidence of postoperative nausea and vomiting (PONV)
Proportion of participants experiencing PONV and requiring antiemetics.
Time frame: 4, 8, 12, 24, and 48 hours after surgery
Length of hospital stay
Duration of hospitalization from surgery to discharge.
Time frame: From surgery to discharge, up to 30 days
Patient satisfaction
Numerical rating scale satisfaction score. 0, not satisfied; 10, absolutely satisfied.
Time frame: 48 hours after surgery
Incidence of hemidiaphragmatic paralysis
Proportion of participants with phrenic nerve palsy after the block.
Time frame: Within 24 hours after the nerve block
Postoperative blood glucose change
Change in blood glucose level on postoperative day 1 compared with baseline.
Time frame: Postoperative day 1
Incidence of surgical and anesthetic complications
Surgical complications (surgical site infection, delayed wound healing) and anesthesia-related complications (nerve injury, local anesthetic systemic toxicity, catheter-related problems such as dislodgement, leakage, or infection).
Time frame: Up to 30 days after surgery
Plan to share: No — Individual participant data will not be shared because the informed consent obtained from participants does not include provisions for data sharing with third parties.
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Seoul National University Hospital