Comparison of 90° and 120° Arm Positions in Costoclavicular Block (COSTO-RCT)

Effect of Arm Abduction Degree ( 90° vs. 120° ) on Block Onset Time and Block Success in Costoclavicular Brachial Plexus Block in Patients Undergoing Hand, Wrist and Forearm Surgery: A Prospective Randomized Controlled Trial

The costoclavicular approach of the infraclavicular brachial plexus block is widely used for upper extremity surgeries due to its reliable anatomy and high success rates. Patient positioning, particularly the degree of arm abduction, may influence the spread of local anesthetic and the characteristics of the block. However, the optimal arm abduction angle during this procedure remains unclear.

This prospective randomized controlled trial aims to investigate the effect of two different arm abduction angles (90° and 120°) on block onset time and block success in patients undergoing hand, wrist, and forearm surgery under ultrasound-guided costoclavicular brachial plexus block.

Patients will be randomly assigned to one of two groups according to the degree of arm abduction. The primary outcome is block onset time. Secondary outcomes include block success, sensory and motor block characteristics, perfusion index changes, hemodynamic parameters, readiness for surgery at 15 and 20 minutes, block performance time, need for additional anesthesia, postoperative neurological evaluation at 4 and 24 hours, complications, and patient satisfaction.

The findings of this study are expected to provide evidence on optimal patient positioning to improve the effectiveness and reliability of ultrasound-guided costoclavicular brachial plexus block.

Study Overview

• Status: Not yet recruiting
• Conditions: Brachial Plexus Block; Regional Anaesthesia; Perfusion Index; Upper Extremity Surgery
• Intervention / Treatment: Procedure: Costoclavicular Brachial Plexus Block

Detailed Description

The costoclavicular approach is a recently described infraclavicular technique for brachial plexus block that provides reliable anesthesia for upper extremity surgeries. Due to the compact arrangement of the cords in the costoclavicular space, this technique has gained popularity for its high success rates and consistent anatomy. However, procedural factors such as patient positioning may influence the distribution of local anesthetic and the effectiveness of the block.

Arm abduction is known to alter the anatomical relationships within the infraclavicular region, potentially affecting needle visualization, spread of local anesthetic, and block characteristics. Despite its clinical relevance, there is limited evidence regarding the optimal degree of arm abduction during ultrasound-guided costoclavicular brachial plexus block.

This prospective randomized controlled study aims to compare two different arm abduction angles 90° and 120° in patients undergoing elective hand, wrist, and forearm surgery. After obtaining written informed consent, eligible patients will be randomly assigned into two groups according to the degree of arm abduction.

All procedures will be performed under ultrasound guidance using a standardized technique. The local anesthetic will be administered in the costoclavicular space, and block characteristics will be assessed systematically. The primary outcome is block onset time, defined as the time from completion of local anesthetic injection to the achievement of adequate sensory block for surgery.

Secondary outcomes include block success, sensory and motor block scores, perfusion index measurements, hemodynamic parameters, readiness for surgery at 15 and 20 minutes, block performance time, need for additional anesthesia or conversion to general anesthesia, early complications, postoperative neurological evaluation at 4 and 24 hours, and patient satisfaction assessed using a Likert scale.

The results of this study are expected to provide valuable evidence regarding optimal patient positioning and contribute to improving the clinical effectiveness and reliability of ultrasound-guided costoclavicular brachial plexus block.

• Study Type: Interventional
• Enrollment (Estimated): 106
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Algan TURGUT ÇARSANCAKLI, M.D.; Phone Number: +90 532 486 52 69; Email: alganturgut@gmail.com
• Study Contact Backup: Name: Reyhan POLAT, Professor; Phone Number: +90 532 673 43 10; Email: reyhanp9@gmail.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Patients aged between 18 and 80 years.
• Patients scheduled for elective upper extremity surgery (hand, wrist, forearm).
• Patients classified as ASA I-III.
• Patients who provide informed consent after being informed about the study.

Exclusion Criteria:

• History of previous surgery, scar tissue, tumor, or trauma that may alter brachial plexus anatomy.
• Presence of infection, hematoma, severe edema, burn, or open wound at the block application site.
• Known allergy to local anesthetics or other medications used in the study.
• Coagulopathy, use of anticoagulants, or platelet count < 100,000/mm³.
• History of peripheral neuropathy, neurological deficit, cervical radiculopathy, or CRPS.
• Pregnancy or breastfeeding.
• Patients with BMI < 18 kg/m².
• Patients with BMI > 35 kg/m².
• Severe cardiac, pulmonary, renal, or hepatic failure.
• Mental retardation, communication difficulties, or lack of cooperation.
• Deformity, amputation, or large mass in the surgical extremity that may interfere with sensorimotor assessment.
• Preoperative significant sensory loss, motor weakness, or signs of neurological disease.
• Severe anemia (Hb < 9 g/dL) or polycythemia (Hb > 18 g/dL).
• Psychiatric disorders, substance abuse, or any condition that may interfere with study compliance.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Screening
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 90° Arm Abduction; Patients receive ultrasound-guided costoclavicular brachial plexus block with the arm positioned at 90° abduction.	Procedure: Costoclavicular Brachial Plexus Block; Ultra-sound Guided costoclavicular brachial plexus block performed for upper extremity surgery using a standard local anesthetic technique
Experimental: 120° Arm Abduction; Patients receive ultrasound-guided costoclavicular brachial plexus block with the arm positioned at 120° abduction.	Procedure: Costoclavicular Brachial Plexus Block; Ultra-sound Guided costoclavicular brachial plexus block performed for upper extremity surgery using a standard local anesthetic technique

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Block Onset Time	Time from completion of local anesthetic injection to achievement of adequate sensory block sufficient for surgery, assessed by pinprick test.	Up to 30 minutes after block performance

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Block Success	Successful completion of surgery without the need for additional anesthesia.	İntraoperative period
Sensory Block Score	Sensory block was assessed using a 3-point pinprick scale ( 0= normal sensation, 1= loss of pinprick sensation, 2= complete sensory block).	Baseline and at 5-minute intervals up to 20 minutes after block performance.
Motor Block Score	Motor block was assessed using a 3-point motor scale (0= normal motor function, 1= reduced motor strength, 20 complete motor block).	Baseline and at 5-minute intervals up to 30 minutes after block performance.
Perfusion Index	Perfusion index values measured using a Masimo pulse oximeter probe placed on the blocked upper extremity.	Baseline and at 5,10,15 and 20 minutes after block performance.
Readiness for Surgery	Proportion of patients ready for surgery at 15 and 20 minutes.	15 minutes after block
Readiness for Surgery	Proportion of patients ready for surgery at 15 and 20 minutes	20 minutes after block
Block Performance Time	Time required to perform the block.	During procedure ( min )
Need for Additional Anesthesia	Requirement for supplemental anesthesia or conversion to general anesthesia.	Intraoperative period
Complications	Early complications related to block	Up to 24 hours
Postoperative Sensory and Motor Function Assessment	Postoperative neurological evaluation including sensory and motor function examination of the blocked upper extremity to assess for neurological complications.	4 hours after surgery
Postoperative Sensory and Motor Function Assessment	Postoperative neurological evaluation including sensory and motor function examination of the blocked upper extremity to assess for neurological complications.	24 hours after surgery
Patient Satisfaction	Patient satisfaction assessed using a 5-point Likert scale, where 1 indicates very dissatisfied and 5 indicates very satisfied.	At the end of the surgery and 24 hours postoperatively
Hemodynamic Parametres	Heart rate	Baseline and at 5,10,15 and 20minutes after block performance
Systolic Blood Pressure	Systolic blood pressure values measured during and after block performance.	Baseline and at 5,10,15 and 20 minutes after block performance.
Diastolic Blood Pressure	Diastolic blood pressure values measured during and after block performance.	Baseline and at 5,10,15 and 20 minutes after block performance.
Mean Arterial Pressure	Mean arterial pressure values measured during and after block performance.	Baseline and at 5,10,15 and 20 minutes after block performance.

Collaborators and Investigators

• Sponsor: Ankara Etlik City Hospital
• Investigators: Study Director: Reyhan Polat, Professor, Ankara Etlik City Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): May 15, 2026
• Primary Completion (Estimated): July 15, 2026
• Study Completion (Estimated): August 27, 2026

Study Registration Dates

• First Submitted: April 7, 2026
• First Submitted That Met QC Criteria: May 8, 2026
• First Posted (Actual): May 14, 2026

Study Record Updates

• Last Update Posted (Actual): May 19, 2026
• Last Update Submitted That Met QC Criteria: May 16, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: AEŞH-EK-2026-07

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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