Additional evidence that C8-T1 roots were blocked by ultrasound-guided interscalene brachial plexus blockade

We would like to thank Pereira et al 1 for their interest in our work and for raising their concerns about the methodology of our recently published study.2 The first critical concern raised by Pereira et al was the possibility that nerve roots C8 and T1 may have been spared by the interscalene blockade of the brachial plexus. Firstly, the muscles at LI4 are innervated mostly by the C8 and T1 spinal nerve roots. We performed the interscalene blockade under ultrasound guidance, which significantly improves its success rate. Roots C8 and T1 can be clearly visualised by ultrasound and it has been reported that successful sensory and motor blockade can be achieved in 99% of patients following ultrasound-guided interscalene brachial plexus blockade.3 Secondly, we assessed sensation and motor function after brachial plexus blockade and demonstrated these to be completely absent in 11 of 12 participants after brachial plexus blockade (table 1). Moreover, participants had no acupuncture sensation during electroacupuncture (EA) after brachial plexus blockade (in the EA+NB session).2 This suggests that roots C8 and T1 were blocked in most, if not all, participants in our …