Endonasal endoscopic resection of the odontoid process in a nonachondroplastic dwarf with juvenile rheumatoid arthritis: feasibility of the approach and utility of the intraoperative Iso-C three-dimensional navigation. Case report - Laufer,I.; Greenfield,J.P.; Anand,V.K.; Härtl,R.; Schwartz,T.H. (J Neurosurg Spine, 2008)