Comparative study of two infraclaviuclar brachial plexus block approaches

Objective:To compare two infraclaviuclar brachial plexus block approaches(VIP and coracoid approach) with regard to the accuracy and safety of nerve location.Methods:Firstly,bilateral infraclavicular regions of ten fresh cadavers were dissected.Clavicle,coracoid,brachial plexus,costal bones and intercostal muscle were exposed.For coracoid approach,the relationship between the brachial plexus and the coracoid(Yc)was analyzed,and the vertical distance(Dc1)between the coracoid puncture site and the surface of the brachial plexus,the horizontal distance(Dc2)between the brachial plexus and the costal bone or intercostal muscle were measured.For VIP approach,the distance(Xv)between the brachial plexus and the VIP puncture site,the vertical distance(Dv1)between the VIP puncture site and the surface of brachial plexus,and the horizontal distance(Dv2) between the brachial plexus and the costal bone or intercostal muscle were measured and recorded respectively.Secondly,20 patients were randomly enrolled and received bilateral infraclavicular ultrasound examination.For those underwent the coracoid approach,the horizontal(Xc)'and vertical(Yc') distances between the transducer centre and the coracoid,the distance(Dc1') between the skin and the axillary artery and the horizontal distance(Dc2') between the transducer centre and the lateral borderline of the pleura were measured and recorded respectively.For those of VIP approach,the distance(Xv') between the centre of the transducer and the puncture site,the distance(Dv1') between the skin and the infraclavicular artery and the horizontal distance(Dv2') between the transducer centre and the lateral borderline of the pleura were measured and recorded respectively.Results:During the coracoid approach,the average Yc was(1.9±0.9)cm and(1.6± 1.0) cm on the left and right side,the difference was significant(P0.05),while for VIP approach,the average Xv was(0.3±0.7) cm and(0.1±0.6) cm on the left and right side respectively,without statistically difference.Dv2 were significantly shorter than that of Dc1,Dc2 in the oracoid approach(P0.05).For coracoid approach,the average Xc' was(1.9±0.6) cm and(1.8±0.6) cm,and the average Yc'(1.8±0.8) cm and(1.8±0.7) cm on the left and right sides respectively,and there were no difference among them.For VIP approach,the average Xv' was(0.1±0.6) cm and(0.1±0.8) cm respectively,with no difference.The average Dv1',Dv2' were significantly shorter than that of Dc1' and Dc2' in the coracoid approach(P0.05).Conclusions:Compared to coracoid approach,the VIP approach has a greater risk of pneumothorax.It's reasonable to choose the midway of the clavicle as the puncture site in the VIP approach,while the coracoid puncture site should be adjusted according to patient's situation.