gms | German Medical Science

Since its introduction by Robinson and Smith 1955, modified by Cloward 1958, cervical discectomy with fusion is an approved operating technique. After using autologous bone graft or bone cement (PMMA), fusion materials like titanium or carbon fibre have become more common over the last years. Some authors describe the problem of cage subsidence and recommend an additional instrumentation. By examining our own patients, we want to verify the rate of subsidence with regard to the clinical outcome.

Between June 2002 and July 2004, 181 patients received an anterior discectomy with titanium or carbon fibre cage fusion in 252 operated levels at our hospital. Out of this group, 80 patients (123 operated levels) attended the follow-up examination at least three months after surgery with X-rays of their cervical spine so far. We retrospectively reviewed the clinical and radiological findings, especially taking a look at the cage subsidence. More patients are to be recruited for the final paper.

Three months after surgery, 62 patients (77.5%) had an excellent or good clinical result. 18 patients (22.5%) remained with a poor clinical outcome. Radiologically, 24 patients (30%) showed cage subsidence in at least one operated level. Out of this group with subsidence, 16 patients turned out having a good or excellent, 8 patients a poor clinical result. Out of the group without signs of subsidence, 46 patients were clinically satisfied, whereas 10 patients had a bad outcome.

We did not find subsidence as often as described by some authors. It is true that in our study, subsidence occurred more often in patients with a clinically poor rather than a good outcome, but not exclusively. So subsidence for itself cannot be the explanation for a bad clinical result. We conclude that after anterior cervical discectomy with cage fusion, an additional instrumentation is not routinely necessary.