gms | German Medical Science

Objectives: Hybrid-operating rooms (hybrid-OR) are used in different fields of surgery. In spine surgery the possibility of a high resolution 2D images and the possibility of 3D-scans showed promising results in minimal invasive pedicle screw placement. In combination with the possibility of 3D-navigation even pedicle screw placement in the upper thoracic spine can be done minimal invasive. Still, the disadvantage of high cost and possible increased radiation needs to be compensated with high accuracy and safety.

Methods: From June 2014 till December 2019 a hybrid operating room was used for minimal invasive pedicle screw placement in a level-1-trauma center. It consists of a floor-based flat-panel robotic C-arm with 3D-scan capability (Artis Zeego, Siemens; Germany) combined with navigation (BrainLAB Curve, BrainLAB; Germany). All patients with fractures T1 to L5 were included in the study.In all cases a Jamshidi needle was advanced through the pedicle and a K-wire was placed. If 2D image quality did not allow safe placement 3D-navigation was used to place the K- wire. Afterwards 3D-scan was performed to control perfect position of the K-wire and pedicle screw thickness and length was planned in the 3D-scan before placement of the screws. If a K-wire needed repositioning another 3D-Scan was performed.Postoperative CTs were used to evaluate perforation of the pedicle screws. Screw perforation grade was assessed as grade I when completely within the pedicle, II < 2 mm, III 2-4 mm, and IV>4 mm outside the pedicle.

Results and Conclusion: Overall 354 screws were placed in the upper thoracic spine (T1-T6), 746 in the lower thoracic spine (T7-T12) and 645 in the lumbar spine. Navigation was used in 31 out of 57 upper thoracic spine cases, in 12 out of 123 lower thoracic spine cases and in 12 out of 146 lumbar spine cases. In 33 out of 327 cases at least one K-wire was changed after the 3D-Scan. Overall 1562 pedicle screws were completely within the pedicle, 167 were assessed as grade II, 16 as grade III and 0 as grade IV. So overall 99,1% of the screws showed perforation less than 2mm. Mean radiation was 335 +/- 26 mGy and significantly higher in the upper thoracic spine compared to the lumbar spine.

In conclusion, despite higher costs and radiation the hybrid-OR allows highest accuracy and safety in minimal invasive pedicle screw placement in the thoracic and lumbar spine.