Case series: Septa can influence local anesthetic spread during infraclavicular brachial plexus blocks

Abstract

Purpose: To ultrasonically identify the presence of septae within the neurovascular sheath and to assess their effect on local anesthetic spread when performing infraclavicular brachial plexus blocks.Clinical features: Thirty ASA status I and II patients scheduled for minor hand surgeries were enrolled in the study. Ultrasound guided infraclavicular brachial plexus blocks were performed on 28 patients. The images of the local anesthetic spread and the effect of the septum within the neurovascular sheath were analyzed. Septae were present in four of six patients where unilateral local anesthetic spread was seen. Septae were not visualized in the 22 patients with unrestricted local anesthetic spread after the initial injection. All 28 patients underwent their planned operations successfully with adequate anesthesia. Conclusions:Our study shows that the presence of septae within the neurovascular sheath may influence the pattern of local anesthetic spread associated with the infraclavicular approach to brachial plexus blocks. A previous cadaveric study revealed that a compartmentalized neurovascular sheath, and uneven distribution of local anesthetic around the nerve components of the plexus may be associated with failed and partial blocks. 1,2 With the use of nerve stimulators, the success rate of the single injection technique was as low as 44%, especially when only the lateral cord was stimulated. [3][4][5][6] We hypothesized that ultrasonographic identification of septae may be beneficial in performing infraclavicular brachial plexus blocks. The purpose of this study was to ultrasonically identify the presence of septae within the neurovascular sheath and to assess their possible effect on local anesthetic spread.

Speed of onset of ‘corner pocket supraclavicular’ and infraclavicular ultrasound guided brachial plexus block: a randomised observer‐blinded comparison

“…This was performed with a technique similar to that described by Sandhu [14] and modified by Dingemans [6] and Morimoto [7]. Patients were supine with the arm to the side and head turned slightly to the contralateral side.…”

“…It has been suggested that injection of local anaesthetic at this point results in a reliable, rapid onset block within minutes [3]. On the other hand, other workers have reported excellent results with the lateral sagittal infraclavicular approach [6], specifically when local anaesthetic is placed deep to the septum posterolateral to the axillary artery [7,8].Block onset time has clinical importance in many settings in that it can influence the feasibility of brachial plexus block (compared with general anaesthesia) as the primary anaesthesia for minor wrist and hand surgery. Therefore, the primary aim of this study was to test the hypothesis that…”

“…It has been suggested that injection of local anaesthetic at this point results in a reliable, rapid onset block within minutes [3]. On the other hand, other workers have reported excellent results with the lateral sagittal infraclavicular approach [6], specifically when local anaesthetic is placed deep to the septum posterolateral to the axillary artery [7,8].…”

Anesthetic Volume for Ultrasound-Guided “Double Bubble” Infraclavicular Block: Comparison of Ropivacaine 0.75% 30ml Vs 35ml

“…These anatomical variants not only meddle with the medial trunk block, but also with the posterior one. Failed or partial blocks may also be caused by the presence of muscular intersepta, tendinous structures or septa within the neurovascular sheath that can influence the pattern of local anesthetic spread [8]. Other possible variables are related to the injection duration of LA bolus, ultrasonographic imaging difficulties in visualizing infraclavicular region and anatomical structures in high BMI patients that complicate the visual control of LA injection.…”

“…The reference point for USG-ICB is the axillary artery, even though the heterogeneous brachial plexus sonography, the presence of septa within the neurovascular sheath [8], and the absence of a clear nervous target for spreading local anesthetics complicate the study of a minimum effective anesthetic volume. However, the single-injection of anesthetics with the "double bubble" technique [9] assures a high success blockade rate [10].…”