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

June 22, 2026 updated by: Mahdy Mohamed Elghanam, Menoufia University

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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

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

Enrollment (Estimated)

75

Phase

  • Phase 4

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

Adults of both sexes, aged 18 to 70 years American Society of Anesthesiologists (ASA) physical status I-II Scheduled for elective shoulder surgery

Exclusion Criteria:

Pulmonary disease or baseline diaphragmatic dysfunction Refusal to provide informed consent Pre-existing neuropathy in the operated limb Allergy to local anesthetics Infection at the injection site Coagulopathy Pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: Interscalene Block (ISB)
Ultrasound-guided interscalene brachial plexus block targeting the C5-C6 roots, performed approximately 1 hour before surgery. Injectate: 10 mL of 0.25% bupivacaine combined with dexmedetomidine 0.5 µg/kg.
Procedure: Ultrasound-guided interscalene brachial plexus block
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.
Experimental: Suprascapular Nerve Block (SSNB)
Ultrasound-guided suprascapular nerve block was performed proximal to the transverse scapular ligament, approximately 1 hour before surgery. Injectate: 10 mL of 0.25% bupivacaine combined with dexmedetomidine 0.5 µg/kg.
Procedure: Ultrasound-guided suprascapular nerve block
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.
Experimental: Costoclavicular Block (CCB)
Ultrasound-guided costoclavicular brachial plexus block targeting the brachial plexus cords in the costoclavicular space, approximately 1 hour before surgery. Injectate: 20 mL of 0.25% bupivacaine combined with dexmedetomidine 0.5 µg/kg.
Procedure: Ultrasound-guided costoclavicular brachial plexus block
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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of hemi-diaphragmatic paresis
Time Frame: From pre-induction baseline to PACU assessment at train-of-four ratio ≥0.9 (up to approximately 24 hours after the block
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.
From pre-induction baseline to PACU assessment at train-of-four ratio ≥0.9 (up to approximately 24 hours after the block

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Postoperative pain score at rest (static VAS)
Time Frame: At 1, 3, 6, 12, and 24 hours postoperatively
Pain intensity at rest was measured on a visual analogue scale (VAS), where 0 = no pain and 10 = worst imaginable pain.
At 1, 3, 6, 12, and 24 hours postoperatively
Patient satisfaction
Time Frame: 24 hours postoperatively
Overall satisfaction with the procedure and postoperative analgesia, assessed on a 5-point scale (very satisfied, satisfied, neutral, dissatisfied, very dissatisfied).
24 hours postoperatively

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Menoufia University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 25, 2026

Primary Completion (Estimated)

December 1, 2026

Study Completion (Estimated)

January 1, 2027

Study Registration Dates

First Submitted

June 22, 2026

First Submitted That Met QC Criteria

June 22, 2026

First Posted (Actual)

June 26, 2026

Study Record Updates

Last Update Posted (Actual)

June 26, 2026

Last Update Submitted That Met QC Criteria

June 22, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ANESTH50 (Other Identifier: Menoufia university)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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