Background: The brachial plexus courses along the lateral to posterior aspect of the subclavian artery located within the supraclavicular region as a trunk or division. Therefore we hypothesized that 2 injections, one along the lateral and one along the posterior aspect of the brachial plexus, could be performed by changing the angle of the ultrasound probe, thereby achieving a 3-dimensional (3-D) even distribution of local anesthetics. Previously, we confirmed the efficacy of this type of approach with that of a single cluster approach. These findings represent a subsequent study.
Objectives: This study was conducted to confirm the superiority of block quality achieved by 2 injections from 2 planes (control group; group C) over 2 injections in one plane (experimental group; group E).
Study design: A randomized, controlled trial.
Setting: Department of Anesthesiology and Pain Medicine, Gachon University Gil Medical Center.
Methods: In group C (n = 35), the brachial plexus sheath was penetrated in 2 planes by anteriorly altering the angle of the ultrasound probe without changing its position. In group E (n = 35), the upper and lower portions of the brachial plexus sheath were penetrated in one plane. A total of 15 mL of lidocaine 1.5% containing epinephrine (1:200,000) was injected at each point in both groups. The ultrasound-guided supraclavicular brachial plexus block was evaluated every 5 minutes for 30 minutes. The main outcome variables were rates of blockage of all 4 nerves and ulnar nerve sparing.
Results: The rate of blockage of all 4 nerves (median, ulnar, radial, and musculocutaneous nerves) was not significantly different between the 2 groups (94% in group C vs. 86% in group E, respectively; P = 0.232). The number of spared ulnar nerves was similar (1 vs. 5, respectively; P = 0.088). Group procedure times, onset times, and Visual Analog Scale scores for the blocks were similar.
Limitations: For the 2 plane, 2 injection approach, only 2-D imaging was performed rather than 3-D imaging.
Conclusions: Two injections performed in one plane offered similar benefits to 2 injections performed in 2 planes. The 2 techniques provided comparable block qualities and could be viewed as equally effective alternatives.
Keywords: multiple injection; supraclavicular block; ultrasound; Brachial plexus block.