Use of Intraoperative CT Improves Accuracy of Spinal Navigation During Screw Fixation in Cervico-Thoracic Region.

STUDY DESIGN A retrospective analysis of a single centre consecutive series of patients OBJECTIVE.: To test the hypothesis that using a mobile intraoperative computed tomography in combination with spinal navigation would result in better accuracy of lateral mass and pedicle screws between C3 and T5 levels, compared to cone-beam computed tomography and traditional 2D fluoroscopy. SUMMARY OF BACKGROUND DATA Use of spinal navigation associated with 3D imaging has been shown to improve accuracy of screw positioning in the cervico-thoracic region. However, use of iCT imaging compared to a cone-beam CT has not been fully investigated in these types of surgical interventions. METHODS We retrospectively analysed a series of patients who underwent posterior cervico-thoracic fixations using different intraoperative imaging systems in a single hospital. We identified three different groups of patients: Group A, operated under 2D-fluoroscopic guidance without navigation; Group B: O-arm® guidance with navigation; Group C: iCT AIRO® guidance with navigation. Primary outcome was the rate of accurately placed screws, measured on intra or postoperative CT scan with Neo et al. classification for cervical pedicles screws and Gertzbein et al. for thoracic pedicle screws. Screws in cervical lateral masses were evaluated according to a new classification created by the authors. RESULTS Data on 67 patients and 495 screws were available. Overall screw accuracy was 92.8% (95.6% for lateral mass screws, 81.6% for cervical pedicle screws and 90% for thoracic pedicle screws). Patients operated with iCT AIRO® navigation had significantly fewer misplaced screws (2.4%) compared to 2D-fluoroscopic guidance (9.1%) and O-arm navigation (9.7%) (p = 0.0152). Accuracy rate of iCT navigation vs O-arm navigation was significantly higher (p = 0.0042), and there was no statistically significant difference in surgical time between the 3 Groups (p = 0.5390). CONCLUSION Use of high-quality CT associated with spinal navigation significantly improved accuracy of screw positioning in the cervico-thoracic region. LEVEL OF EVIDENCE 3.