Artikel
Application of a stand-alone interbody fusion cage based on porous TiO2
/glass composites: Part 2: biomechanical evaluation after implantation in the sheep cervical spine
Anwendung eines Bandscheibenersatzimplantats aus einer neuartigen porösen TiO2
/Glas-Keramik: Teil 2: Biomechanische Untersuchungen nach Implantation in die Schafs-Halswirbelsäule
Suche in Medline nach
Autoren
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M. C. Korinth
- Neurochirurgische Klinik, Universitätsklinikum der RWTH Aachen
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T. Hero
- Neurochirurgische Klinik, Universitätsklinikum der RWTH Aachen
-
T. Pandorf
- Institut für Allgemeine Mechanik (IAM) der RWTH Aachen
-
D. Zell
- Institut für Allgemeine Mechanik (IAM) der RWTH Aachen
| Veröffentlicht: | 4. Mai 2005 |
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Gliederung
Text
Objective
In a preceding part of the study we implanted polymethyl-methacrylate (PMMA) and a stand-alone interbody fusion-cage, manufactured from a new, porous TiO2/glass composite (Ecopore) in a bisegmental fusion model of 10 sheep cervical spines. During the following 2-4 months radiologic and computertomographic examinations were performed. In this second part we intended the biomechanical evaluation of the operated spine segments with reference to the previously determined morphological findings, like subsidence of the implants, significant increase of the kyphosis angle and degree of the bony fusion along with the interpretation of the results.
Methods
20 sheep cervical spine segments with either PMMA-interposition or Ecopore-fusion in the levels C2/3 and C4/5 were tested in comparison to 10 native corresponding sheep cervical spine segments. Non-destructive biomechanical testing was performed, including flexion/extension, lateral bending and axial rotation using a spine testing apparatus. The three-dimensional range of motion (ROM) was evaluated using an ultrasound measurement system.
Results
In the native spine segments C2/3 and C4/5 the ROM increased in cranio-caudal direction particulary in flexion/extension, less pronounced in lateral flexion and axial rotation (p<0,05). The overall ROM of both tested segments was greatest in lateral flexion, reduced to 52% in flexion/extension and to 16% in axial rotation. After 2 months C2/3- and C4/5-segments with PMMA-fusion and C2/3-segments with Ecopore-interposition showed decrease of ROM in lateral flexion in comparison to the native segments, indicating increasing stiffening. However, after 4 months all operated segments, independent from level or implanted material, were stiffer than the comparable native segments. The decrease of the ROM correlated with the radiological-morphological degree of fusion.
Conclusions
Our evaluation of the new porous TiO2/glass composite as interbody fusion cage has shown satisfactory radiological results as well as distinct biomechanical stability and fusion of the segments after 4 months in comparison to PMMA. After histological analysis of the bone-biomaterial-interface, further examination of this biomaterial previous to an application as alternative to other customary cages in humans are necessary.
