Safety and efficacy of an electron beam melting technique-manufactured titanium mesh cage for lumbar interbody fusion

Abstract

Electron beam melting (EBM) technique enables cage design changes such as the integration of guide rails on the cage surface or a3D matrix for osseointegration. Achange in manufacturing technique or design can lead to adecreased fusion rate or impaired applicability. The aim of the present study was to evaluate cage handling, lordosis reconstruction capability, and fusion rate 1year after surgery. In this study, 50patients 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 12months 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. 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. The implant is safe and leads to avery high fusion rate. Alearning curve results from the fact that the cage follows adefined radius dictated by the guide rails. Addressing this, exact placement at the anterior endplate can be achieved.