gms | German Medical Science

126. Kongress der Deutschen Gesellschaft für Chirurgie

Deutsche Gesellschaft für Chirurgie

28.04. - 01.05.2009, München

Intraoperative CT with integrated navigation system in spinal neurosurgery

Meeting Abstract

  • corresponding author S.N. Zausinger - Neurochirurgische Klinik, Klinikum Großhadern, LMU, München
  • B. Scheder - Neurochirurgische Klinik, Klinikum Großhadern, LMU, München
  • E. Uhl - Abt. für Neurochirurgie, LKH Klagenfurt, Österreich
  • T. Heigl - Neurochirurgische Klinik, Klinikum Großhadern, LMU, München
  • D. Morhard - Institut für Klinische Radiologie, Klinikum Großhadern, LMU, München
  • J.C. Tonn - Neurochirurgische Klinik, Klinikum Großhadern, LMU, München

Deutsche Gesellschaft für Chirurgie. 126. Kongress der Deutschen Gesellschaft für Chirurgie. München, 28.04.-01.05.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09dgch10749

DOI: 10.3205/09dgch732, URN: urn:nbn:de:0183-09dgch7323

Veröffentlicht: 23. April 2009

© 2009 Zausinger et al.
Dieser Artikel ist ein Open Access-Artikel und steht unter den Creative Commons Lizenzbedingungen (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.de). Er darf vervielfältigt, verbreitet und öffentlich zugänglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Introduction: With increased use of spinal instrumentation it was seen that routine fluoroscopy to assess pedicle screw placement is not constantly reliable. The aim of this prospective study was to evaluate workflow, feasibility and clinical outcome of navigated stabilization procedures with data acquisition by intraoperative computed tomography (iCT).

Material and methods: CT data of 88 patients [thoracolumbar instability (n=56), C1/2 instability (n=11), cervicothoracic stabilization (n=21)] were acquired after positioning the patient in the final prone surgical position on a radiolucent operating table. A sliding gantry 40-slice CT (Somatom Sensation Open, Siemens) with an expanded aperture (82 cm) was used for image acquisition. During image acquisition the gantry moved over the patient, avoiding dislocation of catheters or tubes. Data were imported to a frameless infrared-based neuronavigation station (Vector Vision Sky, BrainLAB). Intraoperative CT was obtained to assess the extent of decompression and the accuracy of instrumentation. All patients were clinically evaluated by Odom-criteria postoperatively and after three months. Additionally, a retrospective analysis of navigated stabilizations without intraoperative control-CT were compared with the current prospective series concerning the rate of reoperations and surgery related complications.

Results: Computed accuracy was < 2mm (1.0 ± 0.3 mm) in all cases while anatomical and fluoroscopic landmark control showed sufficient accuracy even in cases of up to five vertebral bodies below the initially registered vertebral body. Additional time necessary for the preoperative image acquisition was 15 ± 5 min. The surgery time-out for iCT until resumption of surgery was 9 ± 2.5 min. Time needed for screw insertion including control-iCT was 127 ± 38 min for transarticular C1/2, 103 ± 20 min for lumbar and 144 ± 43 min for thoracic transpedicular screw placement. Control-iCT revealed incorrect screw position > 2 mm without persistent neurological or vascular damage in 19/380 screws (5.0%) leading to immediate correction of 9 screws (2.3%). Control-iCT changed the course of surgery in 7 cases (7.9% of all patients). The overall revision rate was 6.8% (3x wound revisions, 2x liquor fistula and one epidural hematoma). There was no reoperation due to implant malposition. In addition, in case of patients with tumors, the extent of resection could be confirmed. Alltogether all patients experienced a significant (p < 0.05) global clinical improvement (Odom after 1 week 2.5 ± 0.6 to 1.9 ± 0.7 after 3 months). The analysis of 161 patients with navigated stabilizations in the pre-iCT-era revealed an overall revision rate of 11.1% with 5.0% of patients requiring screw revision due to malposition.

Conclusion: Intraoperative CT in combination with neuronavigation provides high accuracy of screw placement and thus safety for patients undergoing spinal stabilization. Reoperations due to implant malpositions could be completely avoided. The system can be installed into a pre-existing operating environment without need for special surgical instruments. The setup allows update of the navigation by repeated image acquisition in case of intraoperative changes of the surgical situs. The procedure is rapid and easy to perform without restricted access to the patient and – by replacing pre- and postoperative imaging – is not associated with an additional exposure to radiation. Multidisciplinary use increases utilization of the system and thus improves cost-efficiency relation.

Figure 1 [Fig. 1]