Adjacent-segment “central” atlantoaxial instability and C2–C3 instability following lower cervical C3–C6 interbody fusion: Report of three cases

Abstract

Aim: We report adjacent-segment “central” or “axial” atlantoaxial instability and C2–C3 instability as the cause of delayed neurological worsening following multisegmental cervical spinal stabilization. Materials and Methods: Three male patients aged 34, 56, and 70 years had been operated earlier for cervical spondylosis by multilevel C3–C6 cervical interbody fusion 6–11 years earlier. After an initial improvement for few years, the patients observed relatively rapid clinical deterioration. When admitted, all the three patients were severely quadriparetic and were brought to the hospital on a wheelchair. Central atlantoaxial instability was diagnosed on the basis of our previously published clinical and radiological parameters. C2–C3 instability was essentially diagnosed on the intraoperative observations. The patients underwent atlantoaxial and C2–C3 fixation. Results: All the three patients had rapid clinical recovery that started in the immediate postoperative period. At an average follow-up of 21 months, the patients walked independently. Conclusions: Identification and treatment of adjacent-segment central atlantoaxial and C2–C3 instability can lead to gratifying clinical outcome.

Keywords

• adjacent-segment instability
• central atlantoaxial instability
• cervical interbody fusion