Reply from the authors.

by anaesthetists experienced in both the techniques. There seems to be an inherent bias towards US technique (an experienced anaesthetist should have taken over when more than three to four passes were required in the NS group, .10 needle passes is too high). Is it possible that the NS technique was performed by less-experienced anaesthetists or are people losing skills in doing blocks by nerve stimulator due to increased use of US? (iv) Sham blocks: we further question whether three patients in the US group should have received sham blocks knowing that the blocks were going to fail and not provide any significant analgesia intraoperatively. We strongly support research towards the identification of interscalene block technique which provides good intraand postoperative analgesia along with an ability to decrease the incidence of phrenic nerve palsy. The authors have succeeded in demonstrating that very low volumes can be used successfully with US-guided interscalene block, but better designed (and powered) studies are required to confirm their findings especially to look at incidence of phrenic nerve palsy and duration of analgesia.