SPENG Block Versus Suprascapular and Axillary Nerve Blocks for Pain After Shoulder Arthroscopy (SPENG-RCT)

Analgesic Efficacy of the Shoulder Posterior Pericapsular Nerve Group Block Versus Combined Posterior Suprascapular and Axillary Nerve Blocks for Shoulder Arthroscopy: A Randomized, Blinded, Non-Inferiority Trial

This prospective, randomized, patient- and assessor-blinded, single-center non-inferiority trial will compare the analgesic efficacy of the Shoulder Posterior Pericapsular Nerve Group (SPENG) block with combined posterior suprascapular and axillary nerve blocks in adults undergoing elective shoulder arthroscopy under general anesthesia. Both groups will receive the same total volume and concentration of local anesthetic. The primary outcome will be the highest resting Numeric Rating Scale pain score recorded during the first 24 postoperative hours. Secondary outcomes will include block performance time, sensory block success in suprascapular and axillary nerve territories, opioid consumption, time to rescue analgesia, motor function, diaphragmatic function, postoperative recovery quality, patient satisfaction, and block-related complications.

Study Overview

• Status: Not yet recruiting
• Conditions: Postoperative Pain; Shoulder Arthroscopy
• Intervention / Treatment: Procedure: Shoulder Posterior Pericapsular Nerve Group (SPENG) Block; Procedure: Combined Posterior Suprascapular and Axillary Nerve Blocks

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Murat KAYKAC, MD; Phone Number: +905330258450; Email: drmuratkaykac@gmail.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Age 18 to 70 years
• American Society of Anesthesiologists (ASA) physical status I-III
• Scheduled to undergo elective shoulder arthroscopy under general anesthesia
• Able to understand the Numeric Rating Scale for pain assessment
• Able and willing to provide written informed consent

Exclusion Criteria:

• Known allergy or hypersensitivity to local anesthetics used in the study
• Infection at the planned block injection site
• Coagulopathy or ongoing anticoagulant therapy that cannot be appropriately interrupted for peripheral nerve block
• Pre-existing neurological deficit affecting the operative upper extremity
• Moderate or severe pulmonary disease
• Known diaphragmatic dysfunction
• Chronic opioid use
• Chronic pain syndrome
• Body mass index greater than 35 kg/m²
• Pregnancy or breastfeeding
• Inability to understand or reliably report Numeric Rating Scale pain scores
• Inadequate sonographic window preventing safe performance of the allocated block technique before randomization

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: SPENG Block; Participants assigned to this group will receive an ultrasound-guided Shoulder Posterior Pericapsular Nerve Group (SPENG) block before general anesthesia for shoulder arthroscopy. A total of 20 mL of 0.25% bupivacaine with epinephrine 1:200,000 will be administered as a single injection between the posterior glenoid rim and the deep surface of the infraspinatus muscle.	Procedure: Shoulder Posterior Pericapsular Nerve Group (SPENG) Block; An ultrasound-guided single-injection posterior pericapsular block. With the participant in the lateral decubitus position and the operative shoulder uppermost, a high-frequency linear ultrasound transducer will be placed transversely immediately inferior to the posterior acromion. After identification of the humeral head, articular cartilage, infraspinatus muscle, and posterior glenoid rim, a block needle will be advanced in-plane in a medial-to-lateral direction. The needle tip will be positioned between the posterior glenoid rim and the deep surface of the infraspinatus muscle, and 20 mL of 0.25% bupivacaine with epinephrine 1:200,000 will be injected.; Other Names: SPENG Block
Active Comparator: Posterior Suprascapular and Axillary Nerve Blocks; Participants assigned to this group will receive ultrasound-guided posterior suprascapular and axillary nerve blocks before general anesthesia for shoulder arthroscopy. A total of 20 mL of 0.25% bupivacaine with epinephrine 1:200,000 will be administered, consisting of 10 mL for the posterior suprascapular nerve block and 10 mL for the axillary nerve block.	Procedure: Combined Posterior Suprascapular and Axillary Nerve Blocks; wo ultrasound-guided nerve blocks will be performed. For the posterior suprascapular nerve block, the suprascapular nerve will be identified in the suprascapular notch region beneath the supraspinatus muscle, and 10 mL of 0.25% bupivacaine with epinephrine 1:200,000 will be administered. For the axillary nerve block, the posterior humeral circumflex artery will be identified using color Doppler in the quadrilateral space, and 10 mL of 0.25% bupivacaine with epinephrine 1:200,000 will be administered adjacent to the axillary nerve.; Other Names: Posterior Shoulder Block

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Highest Resting Numeric Rating Scale Pain Score During the First 24 Postoperative Hours	Resting postoperative pain intensity will be assessed using an 11-point Numeric Rating Scale (NRS), ranging from 0 (no pain) to 10 (worst imaginable pain). For each participant, the highest resting NRS score recorded during the first 24 postoperative hours will be used as the primary outcome. Scheduled assessments will be performed on arrival in the post-anesthesia care unit and at 4, 8, 12, and 24 hours after surgery. Resting NRS scores obtained immediately before rescue analgesic administration outside these scheduled assessments will also be included when determining the highest value.	From arrival in the post-anesthesia care unit through 24 hours after surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of Participants With Complete Dual-Target Sensory Block Success	Cold sensation will be assessed over the posterior shoulder (suprascapular nerve territory) and lateral deltoid region (axillary nerve territory) using a 3-point scale: 0 = absent sensation, 1 = reduced sensation, and 2 = normal sensation. Suprascapular sensory component success will be defined as a reduction of at least one grade from baseline in the posterior shoulder region. Axillary sensory component success will be defined as a reduction of at least one grade from baseline in the lateral deltoid region. Complete dual-target sensory block success will require successful sensory blockade in both territories in the same participant.	30 minutes after block completion
Cumulative Opioid Consumption During the First 24 Postoperative Hours	All rescue opioid analgesics administered during the first 24 postoperative hours will be recorded and converted to intravenous morphine-equivalent dose for comparison between groups.	From arrival in the post-anesthesia care unit through 24 hours after surgery
Time to First Rescue Analgesic	Time from completion of the study block to the first administration of rescue analgesic medication for postoperative pain.	From block completion through 24 hours after surgery
Resting Numeric Rating Scale Pain Scores	Resting pain intensity will be assessed using an 11-point Numeric Rating Scale from 0 (no pain) to 10 (worst imaginable pain).	On arrival in the post-anesthesia care unit and at 4, 8, 12, and 24 hours after surgery
Numeric Rating Scale Pain Scores With Movement	Pain intensity during standardized shoulder-related movement will be assessed using an 11-point Numeric Rating Scale from 0 (no pain) to 10 (worst imaginable pain), when clinically feasible.	On arrival in the post-anesthesia care unit and at 4, 8, 12, and 24 hours after surgery
Anterior Shoulder Numeric Rating Scale Pain Score	Pain localized predominantly to the anterior shoulder will be rated separately using an 11-point Numeric Rating Scale ranging from 0 to 10.	At 8, 12, and 24 hours after surgery
Posterior Shoulder Numeric Rating Scale Pain Score	Pain localized predominantly to the posterior shoulder will be rated separately using an 11-point Numeric Rating Scale ranging from 0 to 10.	At 8, 12, and 24 hours after surgery
Proportion of Participants With Hemidiaphragmatic Paresis	Diaphragmatic excursion will be assessed using M-mode ultrasonography. Hemidiaphragmatic paresis will be defined as diaphragmatic excursion 30 minutes after block completion falling to less than 25% of the participant's baseline excursion.	30 minutes after block completion
Change in Diaphragmatic Excursion From Baseline	Diaphragmatic excursion will be measured using M-mode ultrasonography as the difference in diaphragm position between resting expiration and deep inspiration. Three measurements will be obtained and averaged. Change from baseline will be evaluated after the block.	Baseline and 30 minutes after block completion
Shoulder Abduction Motor Strength	Shoulder abduction strength will be evaluated using the Medical Research Council (MRC) scale ranging from 0 to 5, with higher scores indicating greater muscle strength.	Baseline, 30 minutes after block completion, and 24 hours after surgery
Proportion of Participants With Rebound Pain	Rebound pain will be defined as an increase from an NRS pain score of 3 or lower at the preceding assessment to an NRS score of 7 or higher at the subsequent assessment.	During the first 24 postoperative hours
Quality of Recovery-15 Score	Postoperative quality of recovery will be assessed using the 15-item Quality of Recovery questionnaire (QoR-15). The total score ranges from 0 to 150, with higher scores indicating better quality of recovery.	24 hours after surgery
Patient Satisfaction With Perioperative Analgesia	Overall satisfaction with perioperative analgesia will be rated on an 11-point scale from 0 (completely dissatisfied) to 10 (completely satisfied).	24 hours after surgery
Number of Participants With Block-Related Complications	Participants will be assessed for block-related adverse events including hematoma, infection, persistent paresthesia, persistent weakness, and other clinically suspected complications.	From block performance through postoperative day 7
Block Performance Time	Time required to perform the allocated regional anesthesia technique, measured in seconds from the first contact of the ultrasound transducer with the skin until removal of the block needle after completion of local anesthetic injection.	Periprocedural

Collaborators and Investigators

• Sponsor: Izmir City Hospital
• Investigators: Principal Investigator: Murat KAYKAC, MD, İzmir City Hospital; Study Director: Derya ARSLAN YURTLU, Professor, İzmir City Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): November 1, 2026
• Primary Completion (Estimated): May 31, 2027
• Study Completion (Estimated): June 15, 2027

Study Registration Dates

• First Submitted: August 9, 2026
• First Submitted That Met QC Criteria: August 9, 2026
• First Posted (Actual): August 13, 2026

Study Record Updates

• Last Update Posted (Actual): August 14, 2026
• Last Update Submitted That Met QC Criteria: August 12, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: Postoperative analgesia; Regional anesthesia; Shoulder arthroscopy; Suprascapular nerve block; Diaphragm-sparing block; Axillary nerve block; Shoulder Posterior Pericapsular Nerve Group block; SPENG block
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Digestive System and Oral Physiological Phenomena; Dentistry; Dental Physiological Phenomena; Dental Occlusion
• Other Study ID Numbers: SPENG-RCT-2026-01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data underlying the results reported in the primary publication may be made available to qualified researchers upon reasonable request to the principal investigator. Data will be shared after publication of the main study results, subject to approval of the proposed use and compliance with applicable ethical and institutional data-protection requirements.
• IPD Sharing Time Frame: Beginning after publication of the primary study results and available for 5 years thereafter.
• IPD Sharing Access Criteria: Requests from qualified researchers with a scientifically sound proposal will be considered by the principal investigator. Data will be provided in de-identified form for approved research purposes and subject to applicable institutional and ethical requirements.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ANALYTIC_CODE

Drug and device information, study documents

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