gms | German Medical Science

72. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)
Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgie

Deutsche Gesellschaft für Neurochirurgie (DGNC) e. V.

06.06. - 09.06.2021

Alignment shift between pre- and intraoperative CT imaging during navigated spinal instrumentation

Alignementverschiebung zwischen prä- und intraoperativer CT-Bildgebung bei navigierter spinaler Instrumentierung

Meeting Abstract

  • presenting/speaker Nils Hecht - Charité Universitätsmedizin, Berlin, Deutschland
  • Lars Wessels - Charité Universitätsmedizin, Berlin, Deutschland
  • Bettina Komm - Charité Universitätsmedizin, Berlin, Deutschland
  • Georg Bohner - Charité Universitätsmedizin, Berlin, Deutschland
  • Peter Vajkoczy - Charité Universitätsmedizin, Berlin, Deutschland

Deutsche Gesellschaft für Neurochirurgie. 72. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), Joint Meeting mit der Polnischen Gesellschaft für Neurochirurgie. sine loco [digital], 06.-09.06.2021. Düsseldorf: German Medical Science GMS Publishing House; 2021. DocV288

doi: 10.3205/21dgnc273, urn:nbn:de:0183-21dgnc2732

Veröffentlicht: 4. Juni 2021

© 2021 Hecht et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe



Objective: The precision of machine learning algorithms and surface matching and for planning and execution of spinal navigation based on preoperative imaging may be hampered by spinal alignment shifts caused by the intraoperative shift to prone position. In this study, we determined the spinal alignment shift between pre- and intraoperative CT data sets in patients undergoing navigated posterior instrumentation.

Methods: All patients that underwent navigated posterior instrumentation with intraoperative CT imaging between 2014 and 2017 and in whom an additional, preoperative CT was available were included. The alignment shift between the preoperative (supine) and intraoperative (prone) CT before screw insertion was determined using sagittal alignment parameters defined as “modified cobb angle” (CA), “plumb line” (PL) and “translation” (T). Alignment parameters were analyzed according to the anatomic region and the indication for surgery. Also, an explorative risk factor analysis for prediction of an increased likelihood of shift was performed.

Results: We identified 104 patients with a median age of 66 (IQR 56-75). Spinal pathologies were identified as degenerative (35/104; 34%), tumor (35/104; 34%), trauma (21/104; 20%) and infection (13/104; 12%). Pre- and intraoperative alignment parameters differed frequently (in 98% for CA, 92% for PL and in 29% for T) and across all regions of the spine. Region-based analysis showed that shifts in the cervical and thoracic spine were most reliably detected by CA (*p<0.05), whereas shifts in the thoraco-lumbar spine were better identified with PL (*p<0.05). Although the likelihood of an alignment shift was not significantly affected by the presence of an instability risk factor, the need for a long-segment instrumentation (>5 segments) was associated with a significantly higher likelihood of shift (*p<0.05).

Conclusion: Spinal alignment shifts between pre- and intraoperative CT imaging occur frequently and across all regions of the spine, which needs to be considered as a source of inaccuracy for machine learning algorithms and spinal navigation based on preoperative CT imaging alone.