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

Completed

• Conditions: Musculoskeletal Diseases or Conditions

• Registration Number: NCT05045300
• Lead Sponsor: Chinese University of Hong Kong

Brief Summary

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.

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 Timeline

• Study First Submitted: 2021-08-31
• Study First Submitted QC: 2021-09-06
• Study First Posted: 2021-09-16
• Study Start: 2021-09-20
• Status Verified: 2021-11
• Last Update Submitted: 2021-11-11
• Primary Completion: 2021-11-12
• Study Completion: 2021-11-12
• Last Update Posted: 2021-11-15

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 50

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).

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Exclusion Criteria

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

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Visualization of anatomical nerve structures	through study completion, an average of 1 month	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.

Secondary Outcome Measures

Name	Time	Method
Visualization of the presence of anatomical variations	through study completion, an average of 1 month	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.
Presence of artery within the nerve cluster	through study completion, an average of 1 month	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.

Trial Locations

Locations (1)

Department of Anaesthesia & Intensive Care, Prince of Wales Hospital; 🇭🇰 Shatin, New Territories, Hong Kong