The ISG viewing wand: an application to atlanto-axial cervical surgery using the Le Fort I maxillary osteotomy.

Surgical access to the clivus and upper cervical spine may be facilitated by a number of approaches. The Le Fort I maxillary osteotomy has been described to give improved access to the skull base for removal of tumours and treating vertebrobasilar aneurysms. We describe a case in which the combination of a particularly high translocation of the body of C2 and poor mouth opening had precluded a standard transoral approach by restricting access to the operative field. Anterior decompression of the body of C2 was therefore performed via a maxillary down-fracture with the aid of an interactive image guidance system, the ISG Viewing Wand. The ISG Viewing Wand is a new intra-operative 3 dimensional (3D) image guidance system which has now been used in over three hundred neurosurgical cases at Frenchay Hospital, Bristol. We briefly discuss the principles of the viewing wand and describe its unique application providing anatomical navigation in upper cervical spine surgery.