Resident Physician NYU Langone Health, Department of Neurosurgery New York, NY, US
Introduction: In pediatric patients who have undergone instrumentation and fusion of the thoracolumbar spine, there is a consensus that radiographs at two years that do not reveal instrumentation failure are indicative of successful fusion. For the cervical spine, however, a recent Delphi study was unable to reach consensus that stable radiographs at two years were sufficient to assume fusion. Here, we aimed to determine the reliability of radiographs in assessing fusion after cervical spine surgery in children.
Methods: We performed a retrospective study of the Pediatric Spine Study Group registry of children ≤21 years who underwent cervical spine fusion with rigid internal fixation that had both a computed tomography (CT) scan and plain or dynamic radiographs at least 24 months after surgery. Radiographs were reviewed for evidence of hardware failure and reviewers were blinded to CT results.
Results: A total of 36 patients (17 female) were included. Most patients had syndromic etiologies (n=14; 38.9%), followed by congenital (n=12; 33.3%), neuromuscular (n=4; 11.1%), or traumatic (n=4; 11.1%). Twenty-two (61.1%) patients underwent O-C2 fusion, 3 (8.3%) C1-C2 fusion, 6 (16.7%) occipital to sub-axial fusion, 3 (8.3%) C2 to sub-axial fusion, and 1 (2.8%) sub-axial fusion (C4-T3). Thirty-three of the 36 patients (91.7%) had radiographs that revealed concordant findings with their CT scans. Both radiographs and CT demonstrated clear fusion for 31 patients and fusion failure for 2 patients. Radiographs had a positive predictive value for fusion of 96.9%.
Conclusion : In this preliminary study of children who underwent instrumentation/fusion of the cervical spine, there was strong correlation between the absence of hardware failure on cervical spine radiographs and bony fusion on CT scans 2 years postoperatively. Further studies are needed to determine whether radiographs at any time postoperatively are adequate to conclusively demonstrate fusion.