gms | German Medical Science

59. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
3. Joint Meeting mit der Italienischen Gesellschaft für Neurochirurgie (SINch)

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

01. - 04.06.2008, Würzburg

Intra-osseous ultrasonography for pedicular screw placement

Intraossärer Ultraschall zur Lagekontrolle von Pedikelschrauben

Meeting Abstract

  • corresponding author S.R. Kantelhardt - Department of Neurosurgery, Georg-August-University of Göttingen, Göttingen, Germany
  • V. Bockermann - Department of Neurosurgery, Georg-August-University of Göttingen, Göttingen, Germany
  • V. Rohde - Department of Neurosurgery, Georg-August-University of Göttingen, Göttingen, Germany
  • A. Giese - Department of Neurosurgery, Georg-August-University of Göttingen, Göttingen, Germany

Deutsche Gesellschaft für Neurochirurgie. Società Italiana di Neurochirurgia. 59. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie e.V. (DGNC), 3. Joint Meeting mit der Italienischen Gesellschaft für Neurochirurgie (SINch). Würzburg, 01.-04.06.2008. Düsseldorf: German Medical Science GMS Publishing House; 2008. DocMO.04.04

Die elektronische Version dieses Artikels ist vollständig und ist verfügbar unter: http://www.egms.de/de/meetings/dgnc2008/08dgnc060.shtml

Veröffentlicht: 30. Mai 2008

© 2008 Kantelhardt 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 vervielf&aauml;ltigt, verbreitet und &oauml;ffentlich zug&aauml;nglich gemacht werden, vorausgesetzt dass Autor und Quelle genannt werden.


Gliederung

Text

Objective: Pedicle screw fixation is a common procedure for the treatment of spinal instability. A great variety of techniques to minimize the risk of pedicle screw misplacements have been proposed. Most of the proposed techniques such as navigation or robot assistance aid screw positioning itself, but do not allow a direct intraoperative control of the integrity of burr canals or the screw position. Most deviations from the planned trajectory are therefore not diagnosed prior to postoperative CT-scanning, which might explain the 10 to 20% rate of poorly placed screws. We propose a novel technique for the direct intraoperative verification of integrity of intraosseous burr canals prior to the definitive screw placement, using circular sonography.

Methods: A flexible 1.2mm-diameter ultrasound catheter was evaluated for scanning the integrity of intra-osseous burr canals in 78 pedicles in human post mortem spine specimens. The scanning parameters were optimized for visualization of intra-osseous canals. In a second step, the ultrasound catheter was used for the intraoperative analysis of 10 burr canals during pedicle screw fixation for thoracic and lumbar instability. In the ex vivo and in vivo experiments, the integrity of the burr channel as depicted by ultrasound was compared with the pedicle screw position on postoperative CT scans.

Results: On the sonographic images the lumen of the intra-osseous canals containing fluid and bone dust appeared as a hypointense space, which could be delineated from the osseous margin visualized as a continuous line of high intensity signals. Perforations of the pedicle could be diagnosed by the loss of the continuous high intensity bone margin, and appearance of a soft tissue signal. The results closely matched the findings of postoperative CT studies of the burr channels and intraoperative implant placements. No false negatives were found (correct burr channels placement CT:36/Sono:36), in 4% of the cases mild deviations of the burr channels were interpreted as severe deviations (mild deviations CT:11/Sono:8; severe deviations CT:31/Sono:34). Intraoperatively all 10 burr holes were placed correctly (sono and CT).

Conclusions: The ultrasound scanning of intrapedicular burr channels is a straight forward method for the intraoperative evaluation of correct placement of burr channels which may increase the safety of placement of pedicle screws.