Background and objectives The paraneural sheath is a multilayered network of collagen fibers that surround the brachial plexus. Currently, there are no sonographic data on the paraneural sheath of the brachial plexus, which this study aimed to evaluate.
Methods Ultrasound imaging datasets of 100 patients who received a costoclavicular brachial plexus block, using high-definition ultrasound imaging, were retrospectively reviewed. Video files, representing sonograms before and after the local anesthetic injection, from the costoclavicular space and lateral infraclavicular fossa were collated and reviewed by three experienced anesthesiologists. Frequency (yes/no) of ultrasound visualization of the paraneural sheath, septum, and the anterior and posterior compartments was assessed. Representative sonograms from the costoclavicular space and lateral infraclavicular fossa were visually correlated with archived cadaver microanatomic sections from the same location.
Results Datasets of the 98 patients who achieved surgical anesthesia were evaluated. The paraneural sheath, septum, and the anterior and posterior compartments were visualized in 17.3%, 7.1%, 5.1% and 5.1%, respectively, at the costoclavicular space before the brachial plexus block; this contrasts (p<0.001) with their visibility post-block (94.9%, 75.5%, 75.5% and 75.5%, respectively). At the lateral infraclavicular fossa, the corresponding visibility of these structures post-block were 67.7%, 81.5%, 81.5% and 81.5%, respectively. Ultrasound images of the paraneural sheath and septum correlated well with that in the cadaver microanatomic sections.
Conclusion We have demonstrated the paraneural sheath and fascial compartments surrounding the cords of the brachial plexus at the costoclavicular space and lateral infraclavicular fossa using high-definition ultrasound imaging.
- brachial plexus
Data availability statement
No data are available. Not applicable.
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Contributors PA was involved in review of the literature, data review, data analysis and preparation of the manuscript. MKK was involved in conception, planning and design of the report, review of the data and preparation of the manuscript. MAR was involved in review of microanatomic data and editing the manuscript. LYHM was involved in review of the literature, review of the data and editing the manuscript. RKS was involved in review of the literature, data analysis and editing the manuscript. XS-B was involved in review of microanatomic data and editing the manuscript.
Funding This work was locally funded by the Department of Anaesthesia and Intensive Care, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong, SAR, China.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.