Use of a peripheral nerve stimulator in regional anaesthesia : clinical evaluation

Abstract

Halsted performed the first dental nerve block in 1884 and the first brachial block (under direct exposure) in the neck in 1889. Hirschel described the first percutaneous brnchial plexus block in 1911. It is not easily understood how nowadays regional anaesthesia is not a technique of choice in many centres. Possible reasons may be 1) lack of consistent success 2) the time necessary to perform the block 3) the limited duration of the block 4) fear of complications 5) unfamiliarity with various techniques available. Successful regional anaesthesia depends on accurate placement of local anaesthetic in close proximity to the nerve trunks. In most peripheral somatic nerve block the eliciting of parasthesia helps in identifying the correct spot for injection. This has led to the dictum 'No parasthesia, no anaesthesia'. This may however cause nerve damage either directly by the needling or during intra-neural injection of anaesthetic agent. Parasthesiae are subjective feelings and uncooperation by the patient may severely sabotage such a technique. Difficulty in identifying landmarks by thick subcutaneous fat may also hamper accurate regional block placement. The use of a nerve stimulator may help overcome these problems. Its use was first described in 1912 by von Perthes. The patient is spared a lot of discomfort as the eliciting of twitching by stimulating a motor nerve requires a lower electrical stimulus than that to cause parasthesiae in a sensory nerve. It also makes cooperation by the patient to a large extent superfluous.