• Putzier, Michael
• Hölzl, A.
• Strube, P.
• Suleymanov, F.
• Zippelius, T.

Abstract

BACKGROUND:Electron beam melting (EBM) technique enables cage design changes such as the integration of guide rails on the cage surface or a 3D matrix for osseointegration. A change in manufacturing technique or design can lead to a decreased fusion rate or impaired applicability. OBJECTIVE:The aim of the present study was to evaluate cage handling, lordosis reconstruction capability, and fusion rate 1 year after surgery. MATERIALS AND METHODS:In this study, 50 patients who had undergone minimally invasive transforaminal lumbar interbody fusion (TLIF) or open posterior lumbar interbody fusion (PLIF) using an EBM-manufactured cage were retrospectively included. Fusion evaluation was based on routinely performed CTs and flexion-extension radiographs 12 months postoperatively. Lumbar and segmental lordosis were compared between pre-, post, and 1‑year follow-up. Postoperative cage position was used for evaluation of cage handling. RESULTS:The radiological fusion rate was 97% at the 1‑year follow-up. Two cages were placed into the endplates during surgery without an effect on fusion. In 31% of the cages, placement at the anterior third of the disk space was possible. Lumbar lordosis was improved by a mean of 5° and segmental lordosis by a mean of 4°. At final follow-up, 1° was lost in both parameters. No implant-associated complications were registered. CONCLUSION:The implant is safe and leads to a very high fusion rate. A learning curve results from the fact that the cage follows a defined radius dictated by the guide rails. Addressing this, exact placement at the anterior endplate can be achieved.

Topics

• impedance spectroscopy
• surface
• titanium
• electron beam melting