Using electrical nerve stimulation in performing peripheral nerve helps to control the needle position in relation to the nerve and therefore may increase the likelihood of a successful nerve block. Defining the minimal stimulating current accepted also may help to avoid direct contact between nerve and needle or accidental endoneural injection and subsequent nerve lesion.

In recent years there have been many reports where several nerves, parts thereof or plexuses have been anesthetised using a multiple injection approach. That is, nerves in close proximity of each other have been subsequently blocked after using a nerve stimulator to locate them.

It is not clear though, whether a nerve may already be partially anesthetised in this situation and whether that would impair the correct use of a peripheral nerve stimulator.

The aim of this study is to examine the excitability of a peripheral nerve after injecting a small amount of local anesthetic agent or saline solution into the proximity of the nerve.