Assessment of fusion after anterior cervical discectomy.

There is no established method to assess fusion in patients following anterior cervical discectomy. In this study we have made a series of measurements to detect movement between vertebrae adjacent to an operated space. The absence of movement implies structural union between adjacent vertebrae. Measurements have been made in two distinct surgical groups. Group A patients had anterior cervical discectomy with insertion of a BOP graft into the disc space. Group B patients underwent simple anterior cervical discectomy with no spacer or graft material inserted, the disc space being left empty. Details of the measurements and interpretation of results are described. In the absence of a 'gold standard' to assess bony union we propose that these measurement methods provide an objective and scientific method to assess fusion at the operated level after anterior cervical discectomy. Objective measurement of fusion will allow comparison between different surgical techniques that claim fusion as an end point. It will also become possible to study the influence of fusion on clinical outcome in different surgical populations.