Reliability and Importance of Intraoperative CT Navigation in Spinal Surgery: A Single-Center Experience on a Cohort of 235 Cases

Aims: In this retrospective study we investigated the advantages of intraoperative CT (AIRO) versus 3 dimensional fluoroscopy (O-Arm) and report our experience on a series of 235 patients operated for various indications (from 2014–2017). For each indication, our goal was to check the reliability of a navigation system coupled with CT, the learning curve of iCT-navigation, and radiation doses to the patient. We also tried to define the main benefit of i-CT navigation for each group, compared with traditional fluoroscopic control or other 3D imaging methods.

Methods: Retrospective evaluation of a series of 235 patients submitted to spinal surgery, separated in 4 groups: 1 Thoraco-lumbar instrumentations in patients not previously operated; 2 Thoraco-lumbar instrumentations previously operated; 3 Posterior cervical approaches (instrumentation and/or decompression); 4 Anterior cervical instrumentations; 5 Anterior/lateral approaches at thoracic/lumbar levels, removal of extradural tumors via posterior approaches.

Results: Reliability was very high, as shown by the lower number of intraoperatively repositioned screws compared with fluoroscopy or O-arm. Duration of surgery and rate of repositioning significantly diminished in each group, when we compared last operated patients vs initial ones. A learning-curve effect was however not identified in our series (due to the fact that most of the surgeons were already experienced with the O-arm system). Radiation doses were higher in revision cases and anterior approaches (group 2 and 5). One patient in this series (0.005%) needed revision surgery for a malpositioned screw on L5, that was not checked with intraoperative CT after repositioning.

Conclusion: Main benefits of iCT navigation in each group were, in our experience:

1. Group 1: accuracy improvement during screw positioning, decrease of repositioning rate compared with O-arm

2. Group 2: easier identifications of neural structures during microsurgical decompression

3. Group 3: accuracy improvement during screw positioning at cervico-thoracic junction, verification of decompression in cases of cervical hemilaminectomy

4. Group 4: verification of decompression during osteophytes removal

5. Group 5: easier identification of spinal canal during thoracic anterior corpectomies, identification of pathology levels during removal of extradural tumors.