1. Department of Neurologic Surgery, Mayo Clinic, Rochester, MN 55905, USA
2. Mayo Clinic Rhoton Neurosurgery and Otolaryngology Surgical Anatomy Program, Rochesrer, MN 55905, USA
3. Department of Neurosurgery, Hospital Italiano de Buenos Aires, Buenos Aires C1181ACH, Argentina
4. Division of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, 25121 Brescia, Italy
5. Department of Otorhinolaryngology Head and Neck Surgery, Mayo Clinic, Rochester, MN 55905, USA