Accuracy and safety assessment of O-arm assisted cervical pedicle screw placement in children

English Keywords:Pediatric  Cervical pedicle screw  Accuracy  O-arm navigation

English Abstract:

  【Abstract】 Objectives: To evaluate the accuracy and safety of cervical pedicle screw implantation in children with O-arm navigation assistance. Methods: This study retrospectively analyzed 27 pediatric patients with cervical spine disease who underwent cervical pedicle screw implantation with O-arm navigation assistance between January 2015 and December 2021. The patients aged 4-15(8.2±3.2) years, among which, there were 7 cases of atlantoaxial dislocation, 12 cases of congenital cervical-thoracic deformity, 4 cases of neurofibromatosis with cervicothoracic atrophic scoliosis, 2 cases of Gorham′s disease, and 2 cases of neoplasms. All the patients were treated with O-arm navigation-assisted posterior cervical pedicle screw internal fixation. Preoperatively, the pedicle width of each segment was measured on the widest cross-sectional image of cervical CT scans, and pedicles <3.5mm in width were defined as high-risk pedicles, and during operation, cervical pedicle screws(CPS) were inserted under O-arm navigation guidance. The accuracy of CPS implantation was evaluated immediate postoperatively by CT scans(grade 0: no breach; grade 1: breach <25% screw diameter; grade 2: breach by 25%-50% the screw diameter and invading the internal or lower wall; grade 3: breach by 25%-50% the screw diameter and invading the external or upper wall; grade 4: breach>50% screw diameter). The CPS breach numbers and grades of different levels, as well as complications were recorded. Results: A total of 109 CPSs were implanted, the mean preoperative pedicle diameter was 3.49±0.58mm(C3-6), including 36 high-risk screws. And the screw distributions by segments were C1 13(11.9%), C2 25(22.9%), C3 8(7.3%), C4 17(15.6%), C5 14(12.8%), C6 17(15.6%), and C7 15(13.8%). Postoperative CT scan showed that 100(91.7%) CPSs were well positioned(≤grade 2), 5(4.6%) CPSs were of grade 3, and 4(3.7%) CPSs were of grade 4. No surgical complications such as vertebral artery or nerve root injury were found. The C4 vertebra was relatively more likely to undergo wall breakage due to positional influence and navigational excursions. Breach of grade 4 was due to extremely thin preoperative pedicles(mean 2.78mm), which did not require immediate secondary surgical adjustment or removal in the absence of significant neurologic complications. Conclusions: O-arm navigation-assisted CPS placement has a high accuracy in different cervical diseases in children, and therefore is endowed with high safety.