gms | German Medical Science

60th Annual Meeting of the German Society of Neurosurgery (DGNC)
Joint Meeting with the Benelux countries and Bulgaria

German Society of Neurosurgery (DGNC)

24 - 27 May 2009, Münster

Dorsal atlantoaxial instrumentation using intraoperative CT and spinal navigation

Meeting Abstract

  • O. Sakowitz - Neurochirurgische Klinik, Universitätsklinikum Heidelberg
  • J. Tilgner - Neurochirurgische Klinik, Universitätsklinikum Heidelberg
  • A. Unterberg - Neurochirurgische Klinik, Universitätsklinikum Heidelberg
  • K. Kiening - Neurochirurgische Klinik, Universitätsklinikum Heidelberg

Deutsche Gesellschaft für Neurochirurgie. 60. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit den Benelux-Ländern und Bulgarien. Münster, 24.-27.05.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. DocMO.09-03

doi: 10.3205/09dgnc055, urn:nbn:de:0183-09dgnc0550

Published: May 20, 2009

© 2009 Sakowitz et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Objective: The treatment of choice for significant atlanto-axial instability is open reduction and instrumented fusion by screw instrumentation. Both transarticular screw fixation and C1-C2 instrumentation with C1 lateral mass and C2 pedicle screws (“Harms fusion”) have inherent risks to nervous and vascular structures in this region. Modern navigation techniques utilizing intraoperative imaging, such as computed tomography (CT), may help improve the safety of these methods.

Methods: In this study we review our experiences with posterior atlantoaxial instrumentation utilizing spinal navigation on the basis of intraoperative CT. Image datasets were obtained in the operating room by means of a fixed installed CT scanner (“sliding gantry” CT, Siemens Emotion®). Besides evaluating the feasibility of combining intraoperative CT and spinal navigation in this setting, three different types of instrumentation were tested.

Results: A total of 19 patients (7F/12M, average age: 61 years) were operated for atlanto-axial instability. The majority of patients (68%) were operated for dens type 2 fractures with or without pseudarthrosis. Further indications for surgery were trauma to C1, tumor or iatrogenic problems. Two patients underwent transarticular screw fixation, while the remainder were fused using the “Harms”-technique (C1 lateral mass, C2 pedicular). In 8 patients instrumentation was extended to the subaxial spine. Based on our preliminary experience with intraoperative CT-guided navigation, this approach was modified in three patients as to move the entry points of the C1 screws to the junction of the lamina and lateral mass. This procedure was found particularly suitable to avoid excessive bleeding from the lateral venous plexus.

Conclusions: In the original description of the technique, entry points of the C1 lateral mass screws stay underneath the C1 ring thus avoiding conflict with the vertebral artery. On the other hand the venous plexus in this region can be a source of hazardous bleeding. Intraoperative CT-guided navigation can be used to plan optimized routes for C1-C2 screw instrumentation and thus enhance the overall safety.