1. Department of Otolaryngology, University of Tennessee Health Science Center, Memphis, Tennessee, United States
2. Department of Neurosurgery, University of Tennessee Health Science Center, Memphis, Tennessee, United States
3. Department of Otolaryngology, Vanderbilt University Medical Center, Nashville, Tennessee, United States
4. Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, Tennessee, United States
5. Department of Anesthesiology and Critical Care Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, United States