Abstract
Background: Several recent studies have compared incorporation of autograft with that of allograft or synthetic bone substitutes in anterior cervical discectomy and fusion (ACDF). These studies have almost universally relied on plain radiography to assess bone incorporation despite the fact that we know, from similar lumbar spine studies, that bone ingrowth is over-estimated.
Our aim was to determine the exactly whether bone incorporation may be correctly assessed by this method by comparing the results to those obtained by spiral CT imaging.
Methods: 15 patients underwent ACDF. Helical CT scans were obtained. Fusion was defined as trabecular continuity across the disc space anterior, through and posterior to the cage proximally and distally and assessed by two of the authors independently.
Results: 14 of the 15 patients appeared to have solid incorporation of bone graft/substitute on plain radiography, 19 out of 20 cages. These findings were not however replicated on CT imaging. The autograft was not considered to have been incorporated proximally above the cage in 5 cases and distally in 6 cases.
Discussion: The implication of our results is that there is at least a false positive rate of bone incorporation of 20–25%. Pseudarthroses are generally painful and therefore we would recommend that spiral CT imaging is performed in patients who have ongoing pain following ACDF.
Ethics approval: COREC Ethics committee number 06/S1104/34
Interest Statement: None of the authors have received any grants to carry out this research.
Correspondence should be addressed to BASS/BCSS c/o BOA, at the Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London, WC2A 3PE, England.
