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55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e. V. (DGNC)
1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

25. bis 28.04.2004, Köln

Intraoperative CT imaging in computer-assisted thoracolumbar procedures and its influence on surgical decision making and post-operative results

Intraoperative CT-Untersuchungen bei navigationsgeführten Eingriffen an der Brust- und Lendenwirbelsäule und der Einfluss auf Operationsverlauf und postoperative Ergebnisse

Meeting Abstract

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  • corresponding author Kristian Ebmeier - Klinik für Neurochirurgie, Universitätsklinikum Jena, Jena
  • R. Kalff - Klinik für Neurochirurgie, Universitätsklinikum Jena, Jena

Deutsche Gesellschaft für Neurochirurgie. Ungarische Gesellschaft für Neurochirurgie. 55. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 1. Joint Meeting mit der Ungarischen Gesellschaft für Neurochirurgie. Köln, 25.-28.04.2004. Düsseldorf, Köln: German Medical Science; 2004. DocMI.04.02

The electronic version of this article is the complete one and can be found online at:

Published: April 23, 2004

© 2004 Ebmeier 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.




Intraoperative imaging using MRI, CT, or ultrasound has been accepted as an important diagnostic tool in cranial neurosurgery. Despite useful indications there were only few reports about intraoperative imaging in spinal surgery. In may 1998 we installed a mobile CT scanner in our OR which was used consequently for image-guided procedures of the thoracolumbar spine. We report on intraoperative findings and their influence on surgical decision making and the final results in 271 thoracolumbar procedures.


263 dorsal instrumentation procedures and 8 transpedicular biopsies were performed in 132 patients with fractures, in 102 patients with degenerative diseases as well as in 37 patients with tumors. The patients were positioned in prone position on the examination table of the mobile CT scanner (Tomoscan M-EG, Philips Medical Systems). At least 3 small titanium screws were implanted in each vertebra serving as fiducial markers. The image data-set was obtained by performing a low dose volume scan and the ventilation was stopped. For image guidance we used the EasyGuideSpine (Philips). The patient-to-image registration was done on the basis of the titanium screws. Intraoperative CT scans were obtained with a slice thickness of 3 mm in the region of interest.


In 271 surgical procedures we performed 845 CT exams. 269 CT scans were obtained to identify correct spinal level. Additional 269 exams were performed in order to obtain the image data-set for spinal navigation. Only 2 patients were operated without image guidance. Intraoperative CT scans were obtained in 251 procedures. In 202 procedures we performed a single intraoperative examination. In 47 procedures two intraoperative exams were done. Three intraoperative exams were necessary in 2 patients. In 12 procedures the surgeon decided to not perform an intraoperative CT scan. The initial position of pedicle screws was checked in 158 cases, in 27 cases the screws and the placement of the bone graft were monitored simultaneously. In addional 41 procedures the screw position and interbody cages were checked and in 8 cases the screw position and the reposition of a bone fragment were checked in a single examination. Repeated exams were performed in 13 cases in order to monitor the reposition of bone fragments, in 10 cases to check the position of interbody cages, in additional 9 cases to check the placement of a bone graft and in 2 cases in order to monitor the final alignement. Replaced screws were checked in 21 cases. With the help of intraoperatively obtained CT images the surgeons get informations about the relation between screw size, pedicle diameter and vertebral body size respectively as well as about the amount of decompression. As a result of the CT findings 38 pedicle screws were replaced in 32 procedures. Furthermore the area of decompression was extended, interbody cages were replaced and bone fragments were removed. In 3 cases an emergency exam was performed in order to find a possible source of hemorrhage.


In our series intraoperative computed tomography was a powerful tool to improve final surgical results and to reduce the rate of repeated surgery. From our point of view, intraoperative imaging should become an option for complex multilevel spinal instrumentation procedures. In extension to the reported cases intraoperative CT imaging is indicated in difficult procedures of the cervical spine and the craniocervical junction. Further developments are necessary to improve the surgeons comfort and to overcome the technical limitations of the current CT scanner.