gms | German Medical Science

Joint German Congress of Orthopaedics and Trauma Surgery

02. - 06.10.2006, Berlin

Unstable cervical spine injuries: The impact of fusion on adjacent levels

Meeting Abstract

  • E. Lambiris - Department of Orthopaedic Surgery, University Hospital of Patras, Patras, Greece
  • G. Kasimatis - Department of Orthopaedic Surgery, University Hospital of Patras, Patras, Greece
  • M. Tyllianakis - Department of Orthopaedic Surgery, University Hospital of Patras, Patras, Greece
  • E. Panagiotopoulos - Department of Orthopaedic Surgery, University Hospital of Patras, Patras, Greece

Deutscher Kongress für Orthopädie und Unfallchirurgie. 70. Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie, 92. Tagung der Deutschen Gesellschaft für Orthopädie und Orthopädische Chirurgie und 47. Tagung des Berufsverbandes der Fachärzte für Orthopädie. Berlin, 02.-06.10.2006. Düsseldorf, Köln: German Medical Science; 2006. DocW.2.1.1-1732

The electronic version of this article is the complete one and can be found online at:

Published: September 28, 2006

© 2006 Lambiris et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Introduction: Cervical fusion is associated with increased incidence of osteophyte formation in the adjacent levels. The purpose of our study was to evaluate the impact of the type of fusion (anterior or posterior) on adjacent levels.

Methods: One hundred and twelve patients were operated on for unstable cervical spine injuries over a 16-year period (1989-2005) according to the instability criteria of White and Panjabi. Seventy-seven patients underwent anterior instrumented fusion, 32 patients had posterior instrumented fusion, while 3 patients were instrumented both anteriorly and posteriorly. The age of the patients was 41.2 years (17-78 years) on average and the mean follow-up was 8.1 years (2-16 years). Retrospective review of the patients’ radiographs was done by an independent examiner. The presence of adjacent level ossification was identified and graded as Grade 0 (none), Grade 1 (mild) if the ossification extended across <50% of the disc space, Grade 2 (moderate) if the ossification extended across 50% of the disc space, or Grade 3 (severe) if there was complete bridging of the adjacent disc space. Two patients had radiographic evidence of preexisting osteophytes and were subsequently excluded from the study. The plate-to-disc distance was measured in anterior fusions (<5mm vs ≥5mm) and evaluated for possible correlation with the ossification both cranially and caudally. Therapeutic Level of evidence III (retrospective comparative study).

Results: Seventy-four patients (96%) with anterior fusion and twenty-eight patients (87.5%) from the posterior fusion group were eligible for the study. Eight patients (10.8%) from the anterior fusion group developed adjacent level ossification, while no one from the posterior fusion group. One patient had signs of ossification from the 3rd postoperative month, while the remainders developed it after the 1st postoperative year. A plate-to disc distance <5mm was recorded in 5 patients cranially and in 7 patients caudally. Severe ossification (grade 3) was observed in 6 out of 8 patients cranially, while 4 patients had moderate and severe ossification (grades 2 & 3) caudally.

Conclusion: Adjacent level ossification does not occur after posterior cervical fusion. On the contrary, ossification following anterior instrumented fusion is associated with a short distance of the plate to the vertebral endplate, especially cranially. Development of ossification early in the postoperative period, or when the plate-to-disc distance is >5mm can be attributed to tissue injury when placing the plate (anterior longitudinal ligament, anterior annulus) and deserves further investigation.