Interscalene Block Versus Combined Infraclavicular-Anterior Suprascapular Blocks for Shoulder Surgery

A Randomized Comparison Between Interscalene And Combined Infraclavicular-Anterior Suprascapular Nerve Blocks For Arthroscopic Shoulder Surgery

Postoperative analgesia after shoulder surgery remains a challenge in patients with preexisting pulmonary pathology, as interscalene brachial plexus block (ISB), the standard nerve block for shoulder surgery, carries a prohibitive risk of hemidiaphragmatic paralysis (HDP). Although several diaphragm-sparing nerve blocks have been proposed, none seems to offer equivalent analgesia to ISB while avoiding HDP altogether. For instance, even costoclavicular blocks, which initially fulfilled both requirements, were subsequently found to result in a non-negligible 5%-incidence of HDP.

In this randomized trial, the authors set out to compare ISB and combined infraclavicular block-anterior suprascapular nerve blocks (ICB-ASSNB) for patients undergoing arthroscopic shoulder surgery. The authors hypothesized that ICB-ASSNB would provide equivalent postoperative analgesia to ISB 30 minutes after shoulder surgery and therefore designed the current study as an equivalence trial.

Study Overview

• Status: Completed
• Conditions: Pain, Postoperative; Shoulder Pain; Surgical Procedure, Unspecified; Diaphragmatic Paralysis
• Intervention / Treatment: Procedure: Interscalene Block; Procedure: Infraclavicular - Anterior Supraescapular Nerve Blocks

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Chile
  • Santiago Metropolitan
    • Santiago, Santiago Metropolitan, Chile
      • Hospital Clínico Universidad de Chile

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Patients undergoing arthroscopic shoulder surgery
• American Society of Anesthesiologists classification 1-3
• Body mass index between 20 and 35 kg/mt2

Exclusion Criteria:

• Adults who are unable to give their own consent
• Pre-existing neuropathy (assessed by history and physical examination)
• Coagulopathy (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. platelets ≤ 100, International Normalized Ratio ≥ 1.4 or prothrombin time ≥ 50)
• Obstructive or restrictive pulmonary disease (assessed by history and physical examination)
• Renal failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. creatinine ≥ 100)
• Hepatic failure (assessed by history and physical examination and, if deemed clinically necessary, by blood work up i.e. transaminases ≥ 100)
• Allergy to local anesthetics (LAs)
• Pregnancy
• Prior surgery in the neck or infraclavicular region
• Chronic pain syndromes requiring opioid intake at home

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Interscalene Block; Patients randomized to receive an interscalene block.	Procedure: Interscalene Block; Ultrasound-guided brachial plexus block injecting 20 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml in the Interscalene groove. Patients will receive dexamethasone 4 mg intravenously and an ultrasound-guided intermediate cervical plexus block (5 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml).; Other Names: Peripheral Nerve Block
Experimental: Infraclavicular-Anterior Supraescapular Nerve Blocks; Patients randomized to receive a combined infraclavicular plus anterior suprascapular nerve blocks.	Procedure: Infraclavicular - Anterior Supraescapular Nerve Blocks; Ultrasound-guided combined infraclavicular-anterior suprascapular block of the brachial plexus, injecting 20 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml dorsal to the axillary artery in the infraclavicular fossa plus an ultrasound-guided injection of 3 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml under the omohyoid muscle. If the anterior suprascapular nerve could not be identified after five minutes of insonation time, an upper trunk block will be carried out with the same amount of local anesthetic. Patients will receive dexamethasone 4 mg intravenously and an ultrasound-guided intermediate cervical plexus block (5 ml of bupivacaine 0.5% plus epinephrine 5 micrograms per ml).; Other Names: Peripheral Nerve Block

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Static pain 30 minutes after arrival in the post anesthesia care unit (PACU)	Pain intensity at rest using a numeric rating score (NRS) ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)	30 minutes after PACU arrival

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intensity of pain during block procedure	Evaluated with the Numeric Rating Scale for Pain. This scale is graduated from 0 to 10 points. A 0-point score represents the absence of pain, and a 10-points score represents the worst imaginable pain. Patients will be asked to rate their pain verbally with this scale. The blinded assessor will register the score reported.	1 hour before surgery
Persistent neurologic deficit	Presence of persistent sensory or motor postoperative deficit. The patients will be contacted by telephone and inquired about any sensory or motor deficit in the operated extremity.	7 days after surgery
Static pain 1 hour after arrival in the PACU	Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)	1 hour after PACU arrival
Static pain 3 hours after arrival in the PACU	Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)	3 hours after PACU arrival
Static pain 6 hours after arrival in the PACU	Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)	6 hours after PACU arrival
Static pain 12 hours after arrival in the PACU	Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)	12 hours after PACU arrival
Static pain 24 hours after arrival in the PACU	Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)	24 hours after PACU arrival
Static pain 36 hours after arrival in the PACU	Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)	36 hours after PACU arrival
Static pain 48 hours after arrival in the PACU	Pain intensity at rest using a NRS ranged from 0 to 10 (0 = no pain and 10 = worst imaginable pain)	48 hours after PACU arrival
Block performance time	Time from skin disinfection until the end of local anesthetic injection	1 hour before surgery
Incidence of nerve block side effects	Determined by the presence of paresthesia, local anesthetic systemic toxicity, vascular puncture, Horner syndrome, or hoarseness after the block.	0 minutes after skin disinfection to 30 minutes after the nerve block
Sensory and motor block score	The sensorimotor block will be assessed every 5 minutes until 30 minutes after the end of local anesthetic injection using a 14-point composite score that encompasses the sensory functions of the axillary and supraclavicular nerves as well as the motor functions of the axillary, suprascapular, subscapular and lateral pectoral nerves Sensation will be assessed with ice in each nerve territory with a 0 to 2 point scale. 0= no block, patients can feel cold; 1= analgesic block, the patient can feel touch but not cold; 2= anesthetic block, the patient cannot feel cold or touch. The motor function will be assessed for each nerve with a 0 to 2 points scale where 0= no motor block; 1= paresis; 2= paralysis. Successful blocks at 30 minutes correlate with a final score ( sum of all individual sensory and motor scores) of at least 12 points out of 14, with a sensory score of at least 3 points (out of 4 points).	30 minutes after the ending time of local anesthetic injection
Block onset time	Time required to reach a minimal sensorimotor composite score of 12 points out of a maximum of 14 points. The sensorimotor score is described in outcome 12.	1 hour before surgery
Basal diaphragmatic function	Diaphragmatic function evaluated before the nerve block	1 hour before surgery
Incidence of hemidiaphragmatic paralysis (HDP) at 30 minutes after interscalene or infraclavicular-suprascapular block	HDP will be defined as the absence of diaphragmatic motion during normal respiration coupled with absent or (paradoxical) cranial diaphragmatic movement when the patient forcefully sniffs	30 minutes after the ending time of local anesthetic injection
Incidence of HDP 30 minutes after PACU arrival	HDP will be defined as the absence of diaphragmatic motion during normal respiration coupled with absent or (paradoxical) cranial diaphragmatic movement when the patient forcefully sniffs	30 minutes after PACU arrival
Duration of surgery	Time between skin incision and closure (min)	4 hours after skin incision
Postoperative opioid related side effects	Presence of postoperative nausea, vomiting, pruritus, urinary retention, respiratory depression.	48 hours after PACU arrival
Intraoperative opioid requirements	Total amount of fentanyl required during general anesthesia	Intraoperative period
Postoperative opioid consumption	Total amount of morphine required during the first 48 hours after surgery	48 hours after PACU arrival
Patient satisfaction	Patient satisfaction at 24 hours using a 0-10 scale (0 = not satisfied; 10 = very satisfied)	24 hours after PACU arrival

Collaborators and Investigators

• Sponsor: University of Chile
• Investigators: Principal Investigator: Julián Aliste, MD, University of Chile

Publications and helpful links

General Publications

• Tran DQ, Bertini P, Zaouter C, Munoz L, Finlayson RJ. A prospective, randomized comparison between single- and double-injection ultrasound-guided infraclavicular brachial plexus block. Reg Anesth Pain Med. 2010 Jan-Feb;35(1):16-21. doi: 10.1097/AAP.0b013e3181c7717c.
• Tashjian RZ, Deloach J, Porucznik CA, Powell AP. Minimal clinically important differences (MCID) and patient acceptable symptomatic state (PASS) for visual analog scales (VAS) measuring pain in patients treated for rotator cuff disease. J Shoulder Elbow Surg. 2009 Nov-Dec;18(6):927-32. doi: 10.1016/j.jse.2009.03.021. Epub 2009 Jun 16.
• Tran DQ, Elgueta MF, Aliste J, Finlayson RJ. Diaphragm-Sparing Nerve Blocks for Shoulder Surgery. Reg Anesth Pain Med. 2017 Jan/Feb;42(1):32-38. doi: 10.1097/AAP.0000000000000529.
• Tran DQ, Layera S, Bravo D, Cristi-Sanchez I, Bermudez L, Aliste J. Diaphragm-sparing nerve blocks for shoulder surgery, revisited. Reg Anesth Pain Med. 2019 Sep 20:rapm-2019-100908. doi: 10.1136/rapm-2019-100908. Online ahead of print.
• Aliste J, Bravo D, Layera S, Fernandez D, Jara A, Maccioni C, Infante C, Finlayson RJ, Tran DQ. Randomized comparison between interscalene and costoclavicular blocks for arthroscopic shoulder surgery. Reg Anesth Pain Med. 2019 Jan 11:rapm-2018-100055. doi: 10.1136/rapm-2018-100055. Online ahead of print.
• Sivashanmugam T, Maurya I, Kumar N, Karmakar MK. Ipsilateral hemidiaphragmatic paresis after a supraclavicular and costoclavicular brachial plexus block: A randomised observer blinded study. Eur J Anaesthesiol. 2019 Oct;36(10):787-795. doi: 10.1097/EJA.0000000000001069.
• Martinez J, Sala-Blanch X, Ramos I, Gomar C. Combined infraclavicular plexus block with suprascapular nerve block for humeral head surgery in a patient with respiratory failure: an alternative approach. Anesthesiology. 2003 Mar;98(3):784-5. doi: 10.1097/00000542-200303000-00031. No abstract available.
• Aliste J, Bravo D, Finlayson RJ, Tran DQ. A randomized comparison between interscalene and combined infraclavicular-suprascapular blocks for arthroscopic shoulder surgery. Can J Anaesth. 2018 Mar;65(3):280-287. doi: 10.1007/s12630-017-1048-0. Epub 2017 Dec 19.
• Vorster W, Lange CP, Briet RJ, Labuschagne BC, du Toit DF, Muller CJ, de Beer JF. The sensory branch distribution of the suprascapular nerve: an anatomic study. J Shoulder Elbow Surg. 2008 May-Jun;17(3):500-2. doi: 10.1016/j.jse.2007.10.008. Epub 2008 Feb 11.
• Ebraheim NA, Whitehead JL, Alla SR, Moral MZ, Castillo S, McCollough AL, Yeasting RA, Liu J. The suprascapular nerve and its articular branch to the acromioclavicular joint: an anatomic study. J Shoulder Elbow Surg. 2011 Mar;20(2):e13-7. doi: 10.1016/j.jse.2010.09.004. Epub 2010 Dec 30.
• Musso D, Flohr-Madsen S, Meknas K, Wilsgaard T, Ytrebo LM, Klaastad O. A novel combination of peripheral nerve blocks for arthroscopic shoulder surgery. Acta Anaesthesiol Scand. 2017 Oct;61(9):1192-1202. doi: 10.1111/aas.12948. Epub 2017 Aug 4.
• Tran DQ, Dugani S, Finlayson RJ. A randomized comparison between ultrasound-guided and landmark-based superficial cervical plexus block. Reg Anesth Pain Med. 2010 Nov-Dec;35(6):539-43. doi: 10.1097/AAP.0b013e3181faa11c.
• Aliste J, Bravo D, Fernandez D, Layera S, Finlayson RJ, Tran DQ. A Randomized Comparison Between Interscalene and Small-Volume Supraclavicular Blocks for Arthroscopic Shoulder Surgery. Reg Anesth Pain Med. 2018 Aug;43(6):590-595. doi: 10.1097/AAP.0000000000000767.
• Spence BC, Beach ML, Gallagher JD, Sites BD. Ultrasound-guided interscalene blocks: understanding where to inject the local anaesthetic. Anaesthesia. 2011 Jun;66(6):509-14. doi: 10.1111/j.1365-2044.2011.06712.x.
• Franco CD, Williams JM. Ultrasound-Guided Interscalene Block: Reevaluation of the "Stoplight" Sign and Clinical Implications. Reg Anesth Pain Med. 2016 Jul-Aug;41(4):452-9. doi: 10.1097/AAP.0000000000000407.
• Maikong N, Kantakam P, Sinthubua A, Mahakkanukrauh P, Tran Q, Leurcharusmee P. Cadaveric study investigating the phrenic-sparing volume for anterior suprascapular nerve block. Reg Anesth Pain Med. 2021 Sep;46(9):769-772. doi: 10.1136/rapm-2021-102803. Epub 2021 Jun 3.
• Lloyd T, Tang YM, Benson MD, King S. Diaphragmatic paralysis: the use of M mode ultrasound for diagnosis in adults. Spinal Cord. 2006 Aug;44(8):505-8. doi: 10.1038/sj.sc.3101889. Epub 2005 Dec 6.
• Aguirre O, Tobos L, Reina MA, Sala-Blanch X. Upper trunk block: description of a supraclavicular approach of upper trunk at the points of its division. Br J Anaesth. 2016 Dec;117(6):823-824. doi: 10.1093/bja/aew366. No abstract available.
• Aliste J, Cristi-Sanchez I, Bermudez L, Layera S, Bravo D, Tran Q. Assessing surgical anesthesia for shoulder surgery. Reg Anesth Pain Med. 2020 Aug;45(8):675-676. doi: 10.1136/rapm-2019-100981. Epub 2019 Dec 31. No abstract available.

Study record dates

Study Major Dates

• Study Start (Actual): June 13, 2023
• Primary Completion (Actual): November 28, 2025
• Study Completion (Actual): November 28, 2025

Study Registration Dates

• First Submitted: June 28, 2022
• First Submitted That Met QC Criteria: July 1, 2022
• First Posted (Actual): July 6, 2022

Study Record Updates

• Last Update Posted (Actual): December 29, 2025
• Last Update Submitted That Met QC Criteria: December 20, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Postoperative Shoulder Analgesia; Diaphragmatic Paralysis; Alternative Blocks
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Musculoskeletal Diseases; Nervous System Diseases; Postoperative Complications; Pathologic Processes; Joint Diseases; Respiratory Tract Diseases; Respiration Disorders; Arthralgia; Respiratory Insufficiency; Paralysis; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Shoulder Pain; Respiratory Paralysis
• Other Study ID Numbers: OAIC 1248/22

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No