Interscalene Versus Infraspinatus-Teres Minor Blocks for Arthroscopic Shoulder Surgery (ITM-ISB)

May 13, 2026 updated by: Ali Ahiskalioglu, Ataturk University

Comparison of Interscalene and Infraspinatus-Teres Minor Blocks on Postoperative Opioid Consumption and Pain Scores in Patients Undergoing Arthroscopic Shoulder Surgery

This randomized controlled trial aims to compare the effectiveness of interscalene (ISB) and infraspinatus-teres minor (ITM) blocks for postoperative analgesia in patients undergoing elective arthroscopic shoulder surgery. The primary outcome is total 24-hour opioid consumption. Secondary outcomes include pain scores, hemidiaphragmatic paresis incidence and severity, duration of analgesia, and changes in lung function. Participants are randomized into ISB or ITM groups; blocks are performed under ultrasound guidance. Postoperative pain is managed with patient controlled analgesia(PCA).

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

This is a single-center, prospective, randomized clinical trial designed to compare the efficacy of Interscalene Brachial Plexus Block (ISB) and Infraspinatus-Teres Minor (ITM) interfascial block in patients undergoing elective unilateral arthroscopic shoulder surgery. The primary objective is to compare total 24-hour postoperative opioid consumption. Secondary objectives include the and pain scores, incidence and severity of hemidiaphragmatic paresis, duration of analgesia (from block completion to initiation of IV PCA), and postoperative pulmonary function changes.

This study aims to determine whether the ITM block provides comparable perioperative analgesia to the ISB block while potentially reducing hemidiaphragmatic paresis and pulmonary compromise.

Study Type

Interventional

Enrollment (Actual)

60

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

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:

  • The American Society of Anesthesiologists I-III
  • Scheduled for elective unilateral arthroscopic shoulder surgery
  • Provide written informed consent

Exclusion Criteria:

  • Refusal to participate
  • Allergy to study drugs
  • Severe cardiac, renal, or hepatic disease
  • Neurological deficit or neuropathy
  • Anticoagulant therapy
  • Pre-existing respiratory dysfunction
  • Chronic shoulder pain or planned open surgery

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: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Interscalene Brachial Plexus Block (ISB)
Patients will receive ISB under ultrasound guidance prior to arthroscopic shoulder surgery using 15 ml 0.25% bupivacaine.
Procedure: Interscalene Brachial Plexus Block (ISB)
Patients receive ultrasound-guided ISB before arthroscopic shoulder surgery. After sedation with IV midazolam, 15 ml of 0.25% bupivacaine is injected using a 22 Gauge 50 mm needle with posterior in-plane approach, targeting C5-C6 roots.
Other Names:
  • Interscalene Nerve Block
Experimental: Infraspinatus-Teres Minor Block (ITM)
Patients will receive TM block under ultrasound guidance using 25 ml 0.25% bupivacaine between infraspinatus and teres minor muscles.
Procedure: Infraspinatus-Teres Minor Block (ITM)
Patients receive ultrasound-guided ITM interfascial block in sitting position before surgery. Using a 22 Gauge 10 mm needle, 25 ml of 0.25% bupivacaine is injected between infraspinatus and teres minor muscles via out-of-plane or in-plane hydrodissection.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Total 24-Hour Postoperative Opioid Consumption
Time Frame: 0-24 hours postoperatively
Total intravenous opioid consumption recorded for each patient during the first 24 hours after arthroscopic shoulder surgery, including any rescue analgesia administered.
0-24 hours postoperatively

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence and Severity of Hemidiaphragmatic Paresis
Time Frame: Pre-block and 30 minutes post-block
Ipsilateral hemidiaphragmatic function evaluated by M-mode ultrasonography before block and 30 minutes after block completion. Paresis classified as none (<25% reduction), partial (25-75% reduction), or complete (>75% reduction or paradoxical movement).
Pre-block and 30 minutes post-block
Duration of Analgesia
Time Frame: 0-24 hours post-block
Time interval from block completion to initiation of IV PCA fentanyl in each patient.
0-24 hours post-block
Pulmonary Function Changes (FEV1)
Time Frame: Pre-block and 30 minutes post-block
Pulmonary function measured with bedside spirometry pre-block and 30 minutes post-block. Forced expiratory volume in 1 second (FEV1) recorded; each measurement performed three times and mean value used.
Pre-block and 30 minutes post-block
Pulmonary Function Changes (FVC)
Time Frame: Pre-block and 30 minutes post-block
Pulmonary function measured with bedside spirometry pre-block and 30 minutes post-block. Forced vital capacity (FVC) recorded; each measurement performed three times and mean value used.
Pre-block and 30 minutes post-block

Collaborators and Investigators

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

Sponsor

Ataturk University

Investigators

  • Principal Investigator: Ali Ahıskalıoğlu, Professor, Ataturk University Department of Anesthesiology and Reanimation

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 (Actual)

January 1, 2026

Primary Completion (Actual)

May 1, 2026

Study Completion (Actual)

May 2, 2026

Study Registration Dates

First Submitted

November 19, 2025

First Submitted That Met QC Criteria

November 25, 2025

First Posted (Actual)

November 28, 2025

Study Record Updates

Last Update Posted (Actual)

May 14, 2026

Last Update Submitted That Met QC Criteria

May 13, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ATAUNISHOULDER

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared due to patient privacy concerns and institutional regulations. Data will be securely stored and used solely for the purposes of this study and related scientific publications.

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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