Treatment of traumatic cervical spine instability with interbody fusion cages: A prospective controlled study with a 2-year follow-up

Introduction: The purpose of this prospective cohort study was to define indications and analyze the clinical and radiographic results of using interbody cages to surgically treat traumatic cervical spine instability. Patients and methods: 53 patients were treated by monosegmental anterior discectomy and interbody fusion using either autologous tricortical iliac crest bone graft and CSLP (cervical spine locking plate) (bone graft group, n = 26) or Syncage-C fitted with autologous cancellous bone grafts and CSLP (cage group n=27). Indications for surgery were traumatic cervical spine instability classified according to the AO classification as B1, B2, B3, C2, or C3. Intraoperative parameters such as blood toss and operation time were assessed. Prior to surgery and at follow-up (6, 12, and 24 months), evaluation included measurement of neck pain, shoulder/ arm pain, muscle strength, Neck Pain Disability Index (NPDI), and Cervical Spine Functional Score (CSFS). Neurological and overall outcome was assessed using the ASIA impairment scale and Odom's criteria, respectively. In addition, radiographic evaluation, including plain x-rays, flexion-extension views, and CT scans was performed. Fusion, segmental mobility, segmental lordosis/kyphosis and disc space height were determined. Results: Operation time and hospital stay were significantly shorter (p < 0.05) in the cage group than in the bone graft group. After 6, 12, and 24 months there was no difference between either group in pain, muscle strength, NPDI, CSFS, neurological and overall outcome. Although the cage group showed a trend for prolonged fusion process, there was no statistically significant difference between the groups for all radiographic parameters. Conclusion: Under strict indications, cages offer a valid alternative to a tricortical iliac crest bone graft in the surgical treatment of monosegmental traumatic cervical spine instability. Although there was no significant difference between the cage and the bone graft group in the functional and radiographic outcome, less donor site morbidity, a shorter operating time, and a reduced hospital stay might result in cost-effectiveness of cages.