What is the specific term for nonunion at a fusion site in cervical spine surgery?

• A. Pseudarthrosis
• B. Malunion
• C. Arthrodesis
• D. Kyphosis

Answer: (A)

Nonunion at a cervical fusion site is called pseudarthrosis, meaning a false joint forms because the fused segment did not develop a solid bony union. This leaves persistent motion at the intended fusion level, which can cause neck pain and instability, and may lead to neurologic symptoms if the instability compresses neural structures. On imaging, pseudarthrosis is suggested by a lack of bridging bone across the fusion, a radiolucent gap at the graft site, and evidence of motion on flexion–extension views. This differs from malunion, where healing occurs but in an incorrect alignment; arthrodesis refers to the fusion itself (the goal if successful); and kyphosis is a sagittal deformity with excessive forward curvature.