Diaphragm-Sparing Regional Anesthesia Techniques for Shoulder Surgery

Comparison of Interscalene Brachial Plexus Block Versus the Combination of Suprascapular and Infraclavicular Brachial Plexus Block for Shoulder Surgery: A Randomized Controlled Trial With Diaphragmatic Function Assessment

This study will compare two regional anesthesia techniques for shoulder surgery and evaluate their effects on diaphragmatic function. The standard regional anesthesia technique for shoulder surgery is the interscalene brachial plexus block (ISB), which provides effective analgesia but is frequently associated with ipsilateral hemidiaphragmatic paresis due to phrenic nerve involvement.

An alternative diaphragm-sparing strategy is the combination of a suprascapular nerve block (SSNB) and an infraclavicular brachial plexus block (ICB), which may reduce the risk of diaphragmatic dysfunction while maintaining effective analgesia for shoulder surgery.

All participants will receive ultrasound-guided regional anesthesia prior to surgery and will be randomly assigned to one of two groups:

Group 1: Interscalene brachial plexus block Group 2: Suprascapular nerve block combined with infraclavicular brachial plexus block The primary aim of this study is to determine whether the diaphragm-sparing technique reduces the incidence of hemidiaphragmatic paresis while providing analgesia comparable to the standard interscalene block. Diaphragmatic movement will be assessed using ultrasound before and after block placement. Secondary outcomes include postoperative pain intensity, opioid consumption, pulmonary function parameters, and block-related complications.

Study Overview

• Status: Recruiting
• Conditions: Osteoarthritis Shoulder
• Intervention / Treatment: Drug: Ropivacaine 0.2% for Interscalene Block; Drug: Ropivacaine 0.2% for Infraclavicular and Suprascapular Nerve Blocks

Detailed Description

The interscalene brachial plexus block (ISB) is widely used for anesthesia and postoperative analgesia in shoulder surgery because of its reliable and effective pain control. However, ISB is commonly associated with ipsilateral hemidiaphragmatic paresis due to unintended phrenic nerve blockade, which may impair respiratory function, particularly in older patients and in those with pre-existing pulmonary disease.

The combination of a suprascapular nerve block (SSNB) and an infraclavicular brachial plexus block (ICB) has been proposed as a diaphragm-sparing alternative for shoulder surgery. This approach may provide adequate surgical anesthesia and postoperative analgesia while minimizing the risk of diaphragmatic dysfunction.

This randomized controlled trial will compare the interscalene brachial plexus block with the combined suprascapular and infraclavicular brachial plexus block in patients undergoing elective shoulder surgery. Diaphragmatic function will be evaluated using ultrasound imaging before block performance and after block placement. Additional outcomes will include postoperative pain intensity at rest and during movement, opioid consumption, pulmonary function parameters, block-related complications, length of hospital stay, and patient satisfaction.

• Study Type: Interventional
• Enrollment (Estimated): 70
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Malgorzata Reysner, MD PhD; Phone Number: +48618738313; Email: mreysner@ump.edu.pl

Study Locations

• Poland
  • Poznan, Poland, 62-701
    • Recruiting
    • Poznan University of Medical Sciences
    • Contact: Malgorzata Reysner, M.D. Ph.D.; Phone Number: +48 61 873 83 03; Email: mreysner@ump.edu.pl

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age ≥ 65 years
• Elective shoulder surgery
• ASA I-III
• Planned use of regional anesthesia
• Signed written informed consent

Exclusion Criteria:

• Allergy to local anesthetics
• Planned continuous catheter technique
• BMI >40 kg/m²
• Coagulopathy or anticoagulation
• Pre-existing phrenic nerve palsy
• Neurological disorder of the operative limb
• Pregnancy or breastfeeding
• Participation in another clinical trial within 30 days

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Interscalene Block (ISB); Participants will receive a single-shot ultrasound-guided interscalene block using 20 mL of 0.2% ropivacaine.	Drug: Ropivacaine 0.2% for Interscalene Block; Participants in this arm will receive an ultrasound-guided interscalene brachial plexus block using 20 mL of 0.2% ropivacaine. The block will be performed as a single-shot injection prior to shoulder surgery. No suprascapular or infraclavicular block will be performed in this group; Other Names: interscalene brachial plexus block
Active Comparator: Infraclavicular Block (ICB) + Suprascapular Nerve Block (SSNB); Participants will receive two ultrasound-guided single-shot peripheral nerve blocks: Infraclavicular brachial plexus block: 15 mL of 0.2% ropivacaine; Suprascapular nerve block: 5 mL of 0.2% ropivacaine All blocks will be performed under ultrasound guidance.	Drug: Ropivacaine 0.2% for Infraclavicular and Suprascapular Nerve Blocks; Participants in this arm will receive two ultrasound-guided peripheral nerve blocks as part of the diaphragm-sparing strategy: Infraclavicular brachial plexus block: 15 mL of 0.2% ropivacaine Suprascapular nerve block: 5 mL of 0.2% ropivacaine Both injections will be performed as single-shot blocks prior to surgery. No interscalene block will be performed in this arm; Other Names: Infraclavicular brachial plexus block + Suprascapular nerve block

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Hemidiaphragmatic Paresis	Incidence of hemidiaphragmatic paresis, defined as a >75% reduction in diaphragmatic excursion or paradoxical movement on ultrasound M-mode compared with baseline.	before block and 30-60 minutes after block.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain Scores at Rest (NRS 0-10)	Pain intensity at rest measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Pain scores will be recorded at 2, 6, 12, 24, and 48 hours after surgery and analyzed as repeated measures over time.	2 hours postoperatively
Pain Scores at Rest (NRS 0-10)	Pain intensity at rest measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Pain scores will be recorded at 2, 6, 12, 24, and 48 hours after surgery and analyzed as repeated measures over time.	6 hours postoperatively
Pain Scores at Rest (NRS 0-10)	Pain intensity at rest measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Pain scores will be recorded at 2, 6, 12, 24, and 48 hours after surgery and analyzed as repeated measures over time.	12 hours postoperatively
Pain Scores at Rest (NRS 0-10)	Pain intensity at rest measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Pain scores will be recorded at 2, 6, 12, 24, and 48 hours after surgery and analyzed as repeated measures over time.	24 hours postoperatively
Pain Scores at Rest (NRS 0-10)	Pain intensity at rest measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Pain scores will be recorded at 2, 6, 12, 24, and 48 hours after surgery and analyzed as repeated measures over time.	48 hours postoperatively
Pain Scores During Movement (NRS 0-10)	Pain intensity during passive or assisted shoulder movement measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Mean values at each time point will be compared between groups.	2 hours postoperatively
Pain Scores During Movement (NRS 0-10)	Pain intensity during passive or assisted shoulder movement measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Mean values at each time point will be compared between groups.	6 hours postoperatively
Pain Scores During Movement (NRS 0-10)	Pain intensity during passive or assisted shoulder movement measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Mean values at each time point will be compared between groups.	12 hours postoperatively
Pain Scores During Movement (NRS 0-10)	Pain intensity during passive or assisted shoulder movement measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Mean values at each time point will be compared between groups.	24 hours postoperatively
Pain Scores During Movement (NRS 0-10)	Pain intensity during passive or assisted shoulder movement measured using the 0-10 Numerical Rating Scale (0 = no pain, 10 = worst imaginable pain). Mean values at each time point will be compared between groups.	48 hours postoperatively
Total Opioid Consumption	Cumulative dose of opioid analgesics administered during the postoperative period, converted to oral morphine milligram equivalents (MME), will be recorded and compared between groups.	Within 24 hours after surgery.
Block-Related Adverse Events	Incidence of complications related to the regional anesthesia technique, including local anesthetic systemic toxicity (LAST), prolonged sensory or motor deficit, hematoma, infection at the injection site, or nerve injury. Neurological assessment may be performed in the outpatient clinic if required.	From block placement until 30 days after surgery.
Oxygen Saturation (SpO₂)	The lowest recorded peripheral oxygen saturation (SpO₂, %) during the first 24 hours after surgery will be compared between groups.	From block performance until 24 hours after surgery.
Respiratory rate (breaths per minute).	The highest recorded respiratory rate during the first 24 hours after surgery will be compared between groups.	From block performance until 24 hours after surgery.
Incidence of oxygen desaturation (SpO₂ < 92%)	Oxygen desaturation will be defined as the occurrence of at least one episode of peripheral oxygen saturation (SpO₂) < 92%, measured by pulse oximetry, during the first 24 hours after surgery. The outcome will be analyzed as a binary variable (presence or absence of oxygen desaturation).	From block performance until 24 hours after surgery

Collaborators and Investigators

• Sponsor: Poznan University of Medical Sciences
• Investigators: Study Chair: Malgorzata Reysner, MD PhD, Poznan University of Medical Sciences

Study record dates

Study Major Dates

• Study Start (Actual): December 10, 2025
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 31, 2027

Study Registration Dates

• First Submitted: December 4, 2025
• First Submitted That Met QC Criteria: March 13, 2026
• First Posted (Actual): March 16, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 20, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Organic Chemicals; Anilides; Amides; Aniline Compounds; Amines; Ropivacaine
• Other Study ID Numbers: 12/2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: demographics, outcomes, complications.
• IPD Sharing Time Frame: 12 months after publication for 5 years.
• IPD Sharing Access Criteria: reasonable request with DUA.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No