CT-Navigated Percutaneous Posterior Positioning of Pedicle Screws in The Cervical Spine

Abstract

Background To evaluate reliability, practicability and precision of a novel intraoperative computed tomography(iCT)-based (Airo mobile CT scanner, Brainlab, Munich, Germany) navigated procedure to minimally-invasive positioning of cervical pedicle screws.Methods Ten consecutive patients that suffered from a cervical traumatic instability needing posterior fixation were included in this retrospective analysis. Posterior pedicle screws were positioned iCT-navigated percutaneously. After positioning of the screws, a control scan was performed to assess screw placement and correction if needed. All CT scans were randomly evaluated by two investigators with experience in skeletal CT diagnostics. In the iCT scans, positioning of the screws regarding affection of the medial pedicle cortex as well as the neuroforamina were measured. Additionally, image quality was evaluated with a subjective Likert-Scale (0-5) and a semi-objective Assessability score (0-4).Results 44 screws were placed in an average duration of surgery of 139min [83-209]. The average subjective image quality was 3.9 [2-5], the average assessability score was 3.7 [2-4]. 27 screws (61%) were positioned exactly centered in the pedicle. 4 screws perforated the medial wall by more than 2mm [2.8-2.9]. 9 screws were positioned laterally by more than 2mm [2.5-4.9]. No postoperative neurological deficits were observed.Conclusion iCT-navigated percutaneous placement of pedicle screws is a rather safe and reliable method for posterior fixation of the cervical spine that allows fixation of traumatic cervical instabilities with minimal additional trauma. Even in shallow anatomic structures, visualization of instruments and implants allows for minimally invasive surgery.