Effect of Optimal Biological Volume Bupivacaine Liposome Interscalene Brachial Plexus Block on Postoperative Analgesia After Shoulder Arthroscopy

This study aims to evaluate whether 15ml/75mg low-dose bupivacaine liposome is non-inferior to 15ml/133mg standard-dose bupivacaine liposome for postoperative analgesia in interscalene brachial plexus block during arthroscopic shoulder surgery, through a single-center, prospective, double-blind, non-inferiority randomized controlled clinical trial. It will also assess whether 15ml/75mg low-dose bupivacaine liposome is superior to 15ml/133mg standard-dose bupivacaine liposome in terms of diaphragmatic excursion, pulmonary function, duration of block effect, and nerve block-related adverse reactions during interscalene brachial plexus block.

Study Overview

• Status: Enrolling by invitation
• Conditions: Pain and Diaphragmatic Dysfunction After Shoulder Arthroscopy
• Intervention / Treatment: Drug: OBV bupivacaine liposome group; Drug: Standard dose bupivacaine liposome group

Detailed Description

This study is designed as a single-center, prospective, double-blind, non-inferiority randomized controlled clinical trial, to evaluate and compare whether the postoperative analgesic efficacy of 15 mL/75 mg low-dose liposomal bupivacaine for interscalene brachial plexus block in patients undergoing shoulder arthroscopy is non-inferior to that of 15 mL/133 mg standard-dose liposomal bupivacaine, and to further assess whether the low-dose regimen demonstrates advantages over the standard-dose counterpart in terms of diaphragmatic excursion, pulmonary function, duration of block effect, and nerve block-related adverse reactions.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

Study Locations

• China
  • Zhejiang
    • Jiaxing, Zhejiang, China, 314000
      • Jiaxing University Affiliated Hospital

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patients aged 18 years or older.
• ASA classification I-III.
• Arthroscopic shoulder rotator cuff repair, capsular plication, acromioplasty, synovectomy, etc.

Exclusion Criteria:

• Have a history of lung disease.
• Coagulation dysfunction or coagulopathy.
• History of allergy to local anesthetics.
• infection or lesions at the block site; or history of cervical spine disease.
• pregnancy.
• Refusal to participate in the study or inability to communicate.
• Long-term use of opioids.
• Body mass index >35 kg/m2
• Previous history of nerve injury, paralysis, or paresis;

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: OBV bupivacaine liposome group; Following our preliminary study protocol, 13 mL of liposomal bupivacaine (derived from the 20 mL/266 mg commercial formulation) is aspirated and further diluted with 0.9% sodium chloride injection to a final total volume of 53 mL while maintaining the fixed total dose of 266 mg. This diluted preparation is then combined with 2 mL of 0.5% conventional bupivacaine, and the resultant 55 mL mixture is administered to perform interscalene brachial plexus block prior to surgical incision.	Drug: OBV bupivacaine liposome group; Following our preliminary study protocol, 13 mL of liposomal bupivacaine (derived from the 20 mL/266 mg commercial formulation) is aspirated and further diluted with 0.9% sodium chloride injection to a final total volume of 53 mL while maintaining the fixed total dose of 266 mg. This diluted preparation is then combined with 2 mL of 0.5% conventional bupivacaine, and the resultant 55 mL mixture is administered to perform interscalene brachial plexus block prior to surgical incision.
Experimental: Standard dose bupivacaine liposome group; Following the recommendations in published literature and the approved product labeling, 10 mL of liposomal bupivacaine (20 mL/266 mg formulation) is aspirated, combined with 2 mL of 0.5% conventional bupivacaine, diluted to a final total volume of 15 mL with 0.9% sodium chloride injection, and administered to perform ultrasound-guided interscalene brachial plexus block prior to surgical incision.	Drug: Standard dose bupivacaine liposome group; Following the recommendations in published literature and the approved product labeling, 10 mL of liposomal bupivacaine (20 mL/266 mg formulation) is aspirated, combined with 2 mL of 0.5% conventional bupivacaine, diluted to a final total volume of 15 mL with 0.9% sodium chloride injection, and administered to perform ultrasound-guided interscalene

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in numeric rating scale scores for resting pain at 24 hours after surgery	Difference in numeric rating scale scores(0 = no pain, 10 = worst pain; higher numbers indicate greater pain intensity) for resting pain at 24 hours after surgery. Postoperatively, the NRS scale was used to evaluate pain scores.	postoperative 24 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total consumption of morphine milligram equivalents within 72 hours postoperatively	Record opioid analgesics within 72 hours postoperatively, convert to morphine equivalent dose, and calculate the total amount.	within 72 hours postoperatively
Differences in numeric rating scale pain scores at rest and during activity within 0.5 hours, 6 hours, 24 hours, 48 hours, and 72 hours postoperatively	Differences in numeric rating scale (0 = no pain, 10 = worst pain; higher numbers indicate greater pain intensity) pain scores at rest and during activity within 0.5 hours, 6 hours, 24 hours, 48 hours, and 72 hours postoperatively. Postoperatively, the NRS scoring scale was used to assess pain scores.	postoperative 0.5 hours, 6 hours, 24 hours, 48 hours, 72 hours
Complete unilateral HDP during quiet breathing at 0.5 hours 6 hours, and 24 hours after completion of block	A diaphragm excursion of >75% on the blocked side measured under ultrasound is defined as complete unilateral hemidiaphragmatic paralysis (HDP).	postoperative 0.5 hours, 6 hours and 24 hours
Pulmonary function	Use a portable respiratory function tester for bedside testing; have the patient blow three times and take the average.	postoperative 0.5 hours, 6 hours and 24 hours
All adverse events related to surgery and anesthesia occurring within 72 hours postoperatively	Adverse events associated with nerve blocks within 72 hours postoperatively, including pneumothorax, intravascular injection, local anesthetic toxicity, and Horner syndrome, were recorded.	within 72 hours postoperatively
The number of rescue analgesic interventions required within 72 hours postoperatively	The number of analgesic administrations within the first 72 hours postoperatively was recorded.	within 72 hours postoperatively
sensorimotor score	After completion of the block, the simplified sensorimotor assessment scale (3-point method) is used for evaluation, and a total sensorimotor score ≥12 points with a total sensory score ≥3 points is defined as successful brachial plexus block.	postoperative 0.5 hours, 6 hours and 24 hours

Collaborators and Investigators

• Sponsor: Affiliated Hospital of Jiaxing University

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): September 1, 2028
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: August 23, 2026
• First Submitted That Met QC Criteria: August 27, 2026
• First Posted (Actual): August 28, 2026

Study Record Updates

• Last Update Posted (Actual): August 28, 2026
• Last Update Submitted That Met QC Criteria: August 27, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: liposomal bupivacaine; shoulder arthroscopy; respiratory function; diaphragmatic dysfunction
• Additional Relevant MeSH Terms: Neurologic Manifestations; Pathologic Processes; Respiratory Tract Diseases; Respiration Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain; Respiratory Aspiration
• Other Study ID Numbers: 2026-LP-402

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL

Drug and device information, study documents

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