Ultrasound-guided nerve blocks: efficacy and safety.

The introduction of affordable, portable and high-resolution ultrasound machines has rejuvenated interest in regional anaesthesia. The inherent benefits of direct visualisation of nerves and surrounding anatomy, continual observation of the needle tip and spread of local anaesthetic make ultrasound-guided regional anaesthesia highly appealing. However, in the cost-conscious health-care setting and to convince sceptics, there also needs to be evidence of increased benefits and reduced complications. Ultrasound is a rapidly developing area of technology and some of the newer modalities are discussed. This article focusses on the recent growing evidence to support the benefits of its use in nerve and plexus blocks. Common complications of nerve blocks can be avoided with ultrasound but have still been reported. Anatomical variants have been demonstrated by ultrasound and it has proved to be useful in performing regional anaesthesia in difficult situations or where peripheral nerve stimulation is unsuccessful or inappropriate.