Last reviewed July 17, 2022 by Luc Jasmin, MD, PhD, FRCS (C), FACS, Department of Surgery, Johnson City Medical Center, TN; Department of Surgery St-Alexius Medical Center, Bismarck, ND; Department of Neurosurgery Fort Sanders Medical Center, Knoxville, TN, Department of Neurosurgery UPMC Williamsport PA, Department of Maxillofacial Surgery at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team..