[Cave: interscalene catheters].

Interscalene regional anesthesia is an established and highly effective procedure; however, it represents an increased level of risk due to the close proximity of anatomical structures, such as the cervical spinal cord and many vessels. Furthermore, due to inadvertent placement of a catheter close to the cervical spinal cord or into a vessel, as opposed to a single shot injection technique, it remains a latent danger until it is removed. This article describes seven  cases of misplaced catheters.