Does erector spinae block effect somatosensory evoked potentials in volunteers?

The erector spinae block is a newly described regional anaesthetic technique which has the potential to be applied to a wide range of surgeries. It is potentially an alternative to a paravertebral block, an older, effective but much more technically difficult block. One of the benefits of the paravertebral block is that it profoundly blocks the somatosensory evoked potentials of the area that it provides analgesia to[Richardson, et al. The Effect of thoracic paravertebral blockade on Intercostal somatosensory evoked potentials. Anesth Analg 1998:87;373-76]. This potentially reduces the stress response to surgery, and the likelihood of chronic pain following surgery. For the erector spinae block to replace the paravertebral block in clinical practice, it is important to show that it is not only equivalent in terms of analgesia, but should also be equivalent in its ability to block the somatosensory evoked potentials. The aim of this study is to determine whether or not the erector spinae block effects somatosensory evoked potentials in healthy volunteers.