Portal de Periódicos da CAPES

Low Approach to Interscalene Brachial Plexus Block

2011; Lippincott Williams & Wilkins; Volume: 113; Issue: 5 Linguagem: Inglês

10.1213/ane.0b013e318230409a

1526-7598

Sébastien Bloc, Olivier Rontes, L. Mercadal, Alain Delbos,

Spine and Intervertebral Disc Pathology

To the Editor Although we agree with Kim et al.1 that for interscalene block (ISB) injection below C6 provides more distal spread of both sensory and motor block than that after ISB using the more conventional approach, we have several concerns with method described. First, a large volume of local anesthetic was used to improve the spread of the local anesthetic (50 to 55 mL). Even if no signs of toxicity occurred, it seems more appropriate to inject a smaller volume in this highly vascular region to avoid systemic local anesthetic toxicity caused by either intravascular injection or vascular absorption.2,3 Moreover, an injection below C6 under nerve stimulation increases the risk of vertebral artery puncture, which is difficult to compress. Furthermore, under nerve stimulation, it is difficult to specify the exact position of the tip of the needle. The first trunk (C5 to C6) offers branches either to the arm or to the forearm. Thus, when muscular response of the forearm is seen, it is difficult to differentiate between the stimulation of C5 or C6. Only distal responses (i.e., wrist movement) are specific to deeper stimulation (C6, C7 …). Second, we also suggest that this lower approach to ISB should utilize ultrasound guidance. Ultrasound provides direct visualization of the vascular structures (vertebral artery) and of the best site for the injection (below C6). Moreover, the distribution of the local anesthetic is seen, allowing a reduction of the volume of local anesthetic needed. We recently described the similar results during ISB placement under ultrasound guidance.4 Sebastien Bloc, MD Claude Galien Private Hospital Quincy-Sous-Sénart, France [email protected] Olivier Rontes, MD Médipôle Garonne Private Hospital Toulouse, France Luc Mercadal, MD Claude Galien Private Hospital Quincy-Sous-Sénart, France Alain Delbos, MD Médipôle Garonne Private Hospital Toulouse, France