1 Division of Functional Neurosurgery and Stereotactic, Department of Neurosurgery, Friedrich-Alexander University (FAU) Erlangen-Nürnberg, Erlangen, Bavaria, Germany.
2 Department of Anesthesiology, UC San Diego Health Sciences, San Diego, CA, United States.
3 The Spine & Nerve Centers of the Virginias, Charleston, WV, United States.