Paraneural Sheath & Fascial Compartments Surround Brachial Plexus at Supraclavicular Fossa During Selective Trunk Block

Paraneural Sheath and Fascial Compartments Surrounding the Brachial Plexus at the Supraclavicular Fossa: A Retrospective Review of High Definition Ultrasound Images Acquired During Selective Trunk Brachial Plexus Blockade

The aim of this retrospective study is to define the paraneural (fascial) sheath and fascial compartments that surround the brachial plexus at the supraclavicular fossa by reviewing previous ultrasound images from cases that have undergone ultrasound guided selective trunk brachial plexus block.

Study Overview

• Status: Completed
• Conditions: Musculoskeletal Diseases or Conditions
• Intervention / Treatment: Procedure: Ultrasound guided Selective trunk block

Detailed Description

The optimal anatomical plane (relative to the nerve) or the "goal" for local anesthetic (LA) injection during an ultrasound guided (USG) brachial plexus blockade (BPB) at the supraclavicular fossa is currently not known. USG BPB is often described as a "subfascial", "extra fascial", "intracluster", "interfascial", sub-perineural", "intraneural", "corner pocket" or "periplexus" injection. Although this suggests that the local anesthetic is injected into different tissue planes or fascial compartments, even if such planes do exist, as seen in other regions such as popliteal sciatic nerve are not clearly defined at the supraclavicular fossa. However, recently with the use of high definition ultrasound imaging for USG Selective trunk block (SeTB) and principal investigator has often observed distinct paraneural (fascial) sheath and fascial compartments surrounding the brachial plexus at the supraclavicular fossa. These connective tissue layers are also better delineated after the local anesthetic injection. The principal investigator believes these may be the connective tissue layers that previous researchers have referred to in different reports. Currently there are no published data demonstrating the paraneural sheath and fascial compartment surrounding the brachial plexus in-vivo. Principal investigator believes that this fascial layer and compartment influence the spread of LA during USG BPB around the individual elements of the brachial plexus at the supraclavicular fossa and therefore, these anatomical structures have to be delineated so as to improve the safety, success and quality of USG BPB. This study will involve reviewing archived high definition ultrasound images in audio video interleave format from all adult patients who had undergone USG SeTB for surgical anesthesia during upper extremity surgery from January 1, 2020 to June 30, 2021 to define the paraneural sheath and fascial compartments that surround the brachial plexus at the supraclavicular fossa.

• Study Type: Observational
• Enrollment (Actual): 50

Contacts and Locations

Study Locations

• Hong Kong
  • New Territories
    • Shatin, New Territories, Hong Kong
      • Department of Anaesthesia & Intensive Care, Prince of Wales Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Dataset of previous research titled "Selective Trunk Block: A Prospective Non-Randomized Study of Intervention" (approved by the Joint CUHK-NTEC CREC; CREC Ref no: 2020.687-T; Clinical trial registration: NCT04752410) and " Minimum Effective Local Anaesthetic Volume of a 1:1 Mixture of 2% Lidocaine with 5 µg/ml of Epinephrine and 0.5% Levobupivacaine Required for Ultrasound Guided Selective Trunk Block: A Dose Finding Study" (approved by the Joint CUHK-NTEC CREC; CREC Ref no:2020.680-T; Clinical trial registration: NCT04773405) will also be retrieved.

Description

Inclusion Criteria:

• Archived high definition ultrasound images (datasets) in audio video interleave (AVI) format from all adult patients who had undergone ultrasound guided selective trunk block for surgical anesthesia during upper extremity surgery since the year 2020 (from 01/01/2020 to 30/06/2021).

Exclusion Criteria:

• patients > 75 years old
• American Society of Anesthesiologists (ASA) physical status > Ⅲ
• previous history of surgery at ipsilateral neck.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visualization of anatomical nerve structures	Two anesthesiologists with extensive experience in regional anesthesia and familiar with the fascial anatomy of the brachial plexus at the supraclavicular fossa will independently review the archived ultrasound images and compare the presence of anatomical nerve structures before and after local anesthetic injection. The structure viewed will be scored as 0=no, 1= yes. If a structure is visualized then a previously reported four-point numerical scale, (0=not visible, 1= hardly visible, 2=well visible, 3= very well visible_ will be used to assess the quality of ultrasound visibility. The total ultrasound visibility score (UVS) of the anatomical structures in the transverse scan will be calculated for every subject (maximum score possible = 30) and the mean total UVS will be determined by averaging the scores of the two observers. Inter-rater agreement of the aforementioned anatomical structures between the anesthesiologist will be calculated using kappa statistics.	through study completion, an average of 1 month

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Visualization of the presence of anatomical variations	Two anesthesiologists with extensive experience in regional anesthesia and familiar with the fascial anatomy of the brachial plexus at the supraclavicular fossa will independently review the archived ultrasound images and compare the presence of anatomical variations before and after local anesthetic agent injection. It will be scored as 0=not presence, 1=presence.	through study completion, an average of 1 month
Presence of artery within the nerve cluster	Two anesthesiologists with extensive experience in regional anesthesia and familiar with the fascial anatomy of the brachial plexus at the supraclavicular fossa will independently review the archived ultrasound images and evaluate the presence or absence of blood vessels inside the nerve cluster at the supraclavicular fossa. A score of 0=not presence and 1=presence.	through study completion, an average of 1 month

Collaborators and Investigators

• Sponsor: Chinese University of Hong Kong

Study record dates

Study Major Dates

• Study Start (Actual): September 20, 2021
• Primary Completion (Actual): November 12, 2021
• Study Completion (Actual): November 12, 2021

Study Registration Dates

• First Submitted: August 31, 2021
• First Submitted That Met QC Criteria: September 6, 2021
• First Posted (Actual): September 16, 2021

Study Record Updates

• Last Update Posted (Actual): November 15, 2021
• Last Update Submitted That Met QC Criteria: November 11, 2021
• Last Verified: November 1, 2021

More Information

Terms related to this study

• Keywords: Selective Trunk block
• Additional Relevant MeSH Terms: Musculoskeletal Diseases
• Other Study ID Numbers: CRE.2021.474

Drug and device information, study documents

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