Einfluss von Design und Implantationstechnik auf das Risiko der progredienten Sinterung verschiedener HWS-Cages

Abstract

The aim of this study was to compare the subsidence of differently designed cervical interbody fusion devices under defined conditions. Forty-five bovine vertebral bodies were dissected from soft tissue and cartilage. The bony end plate was then taken off by 0, 1, and 2 mm. Five vertebral bodies of each abrasion depth were prepared for the uptake of a fusion device. Thus, three different fusion devices of comparable size underwent biomechanic testing in a Zwick testing machine with 4000 cycles of axial compression between 50 and 1000 N. Every 1000 cycles, the subsidence into the vertebral body was measured. Abrasion of the end plate resulted in an increased subsidence. The cage with rectangular shape and the cage with cylindric body and lateral wings showed better resistance to axial compression as long as the end plate remained intact. When the end plate was taken off, the subsidence was as high as in the cylindric cage, of which the subsidence did not correlate to the end plate abrasion. During preparation of the implant bed, the cortical bone of the end plate must be treated carefully. In cases of intact end plate, rectangular supporting areas can decrease the risk of subsidence.

Polyetheretherketone (PEEK) Spacers for Anterior Cervical Fusion: A Retrospective Comparative Effectiveness Clinical Trial

“…Several studies have asserted that the preparation of the endplates has an influence on subsidence [7, 11-13]. And at least one study has stated that excessive distraction of the intervertebral space has an influence on the probability of subsidence [14, 15].…”

Primary stability of anterior lumbar stabilization: interdependence of implant type and endplate retention or removal

“…However, not mentioned at all in the literature are comparable biomechanical investigations between ALIF with and without endplates using parameters (ROM, NZ, stiffness), which characterize the stability of the motion segment. A number of studies have made comparisons between the different cages in conjunction with ALIF and with the physiologic specimens [15,25,26,37]. In 2000, Kanayama et al undertook biomechanical investigations on calves using six different cages, one of which was the Harms cage, and observed no statistically significant differences [25].…”

Outcome After Anterior Cervical Discectomy and Arthrodesis

“…In a systematic study by Ba¨erlocher et al 6 a significant lower subsidence rate has been noticed in patients undergoing anterior arthrodesis using titanium or Polymethyl-methacrylate (PMMA)-cages in comparison without implant or with autogenous bone graft. Another study carried out by our group 37 showed a correlation between the spacer material and the subsidence rate. Spacer configuration with enhanced surface structuring or small surface area showed a higher subsidence rate.…”

“…Spacer configuration with enhanced surface structuring or small surface area showed a higher subsidence rate. 37 regards an over distraction a potential hazard for subsidence. Brower and colleagues 42 identified that a distraction of more than 4 mm of the original height could set a trend of nonfusion.…”