Factors affecting localization and dispersion of alcohol in peripheral nerve block

To explore the relationship between electrical current and nerve-needle distance for localization of target nerves in peripheral nerve block, and the effects of injection speed, concentration, and injectate volume on alcohol dispersion using an animal model. Rabbit tibial nerves were selected for localization. Nerve-needle distance was ascertained using a manipulator. The minimum current eliciting motor responses was recorded at nerve-needle distances of 0, 1, 2, 3, 4 and 5 mm. Rabbit tibial nerves were assigned into 3 groups: speed group, concentration group, and volume group. Nerves were localized by a stimulator and neurolysed with alcohol/contrast medium. Helical computed tomography (CT) was performed to measure volume/dispersion patterns of injectate. A linear relationship was observed between nerve-needle distance (X) and minimal current (Y) (Y = 0.13X + 0.22; r2 = 0.974; p