Incidence of sub-perineural injection using a targeted intracluster supraclavicular ultrasound-guided approach in cadavers

Abstract

Background: Multi-injection targeted intracluster injection ultrasound-guided supraclavicular brachial plexus block has been advocated to provide a faster onset of anaesthesia compared with a double injection technique. By placing the needle within clusters of hypoechoic structures, corresponding to neural tissue, this technique may increase needle trauma and the incidence of nerve injury. This study assessed the rate of sub-perineural needle placement with a single intracluster brachial plexus injection in the supraclavicular fossa of human cadavers. Methods: A single ultrasound-guided intracluster brachial plexus injection was performed bilaterally at the supraclavicular fossa on 21 lightly embalmed clinical grade cadavers. Using an in-plane technique, an echogenic needle was positioned to target the middle or lower trunk 'cluster', where 0.2 ml black India ink was injected. An effort was taken to avoid the hypoechoic structures with the needle tip. Tissue samples were assessed histologically by two experienced reviewers. Results: All 42 injections were sonographically assessed to be within the 'main cluster'. Ink was extra-epineural in 13/41 (32%), sub-epineural but outside perineurium in 18/41 (44%), and sub-perineural in 10/41 sections (24%; 95% confidence interval, 13e41%). The histology from one injection was uninterpretable. Of the 10 sub-perineural deposits, the ink was intrafascicular in nine sections. Conclusions: We observed a high rate of sub-perineural injection with a single intracluster injection. Thus the targeted intracluster injection supraclavicular block cannot be recommended until further evidence is available regarding the safety of this technique.

Vulnerability of different nerves to intrafascicular injection by different needle types and at different approach angles: a mathematical model

“…From this current study, we can confirm that the prevailing ideas around intrafascicular and extrafascicular injection13 14 as a consequence of deliberate or accidental intraneural injection are most probably incorrect. This follows our paper4 that clearly demonstrated that injection into the endoneurium of a fascicle is highly unlikely to impossible.…”

Truncal injection brachial plexus block: A Description of a novel injection technique and dose finding study

“…Chances of drug being injected within the perineurium during sub-epineural injections are being highlighted in recent cadaver studies. [ 25 26 ] Hence, a novice anaesthesiologist should develop adequate needling skills before contemplating on sub-epineural injections and executing needle choices.…”

Comparison of ultrasound-guided supraclavicular and costoclavicular brachial plexus block using a modified double-injection technique: a randomized non-inferiority trial

“…Third, the safety of needletip placement inside the neural clusters is controversial. Most studies seem to support the safety and effectiveness of subfascial injection technique [23][24][25]15], however a recent cadaver study reported that a single ultrasound-guided intracluster injection could lead to a high risk of sub-perineural injections (24%) in the supraclavicular fossa [26]. A stimulating current of 0.4 mA was commonly used to avoid intraneural injection and we did discontinue needle advance and LA injection in the presence of pain or high injection resistance in the present study.…”