gms | German Medical Science

German Congress of Orthopaedics and Traumatology (DKOU 2016)

25.10. - 28.10.2016, Berlin

PLGA-fiber reinforcement of injectable calcium phosphate cement enhances bone regeneration in an in vivo vertebral body augmentation model

Meeting Abstract

  • presenting/speaker Francesca Gunnella - Waldkrankenhaus "Rudolf Elle" GmbH, AG Experimentelle Rheumatologie, Lehrstuhl für Orthopädie, Universitätsklinikum Jena, Eisenberg, Germany
  • Stefan Mänz - Lehrstuhl Materialwissenschaft , Otto-Schott-Institut für Materialforschung, FSU Jena, Jena, Germany
  • Bernhard Illerhaus - Abteilung 8 Zerstörungsfreie Prüfung, Fachgruppe 8.5 Mikro-ZfP, Bundesanstalt für Materialforschung und -prüfung, Berlin, Germany
  • Matthias Bungartz - Waldkrankenhaus "Rudolf-Elle" GmbH, Eisenberg, Germany
  • Olaf Brinkmann - Waldkrankenhaus "Rudolf-Elle" GmbH, Eisenberg, Germany
  • Elke Kunisch - Waldkrankenhaus "Rudolf Elle" GmbH, AG Experimentelle Rheumatologie, Lehrstuhl für Orthopädie, Universitätsklinikum Jena, Eisenberg, Germany
  • Jörg Bossert - Lehrstuhl Materialwissenschaft , Otto-Schott-Institut für Materialforschung, FSU Jena, Jena, Germany
  • Raimund W. Kinne - Waldkrankenhaus "Rudolf Elle" GmbH, AG Experimentelle Rheumatologie, Lehrstuhl für Orthopädie, Universitätsklinikum Jena, Eisenberg, Germany

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2016). Berlin, 25.-28.10.2016. Düsseldorf: German Medical Science GMS Publishing House; 2016. DocPO30-463

doi: 10.3205/16dkou796, urn:nbn:de:0183-16dkou7960

Published: October 10, 2016

© 2016 Gunnella et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. See license information at http://creativecommons.org/licenses/by/4.0/.


Outline

Text

Objectives: Injectable calcium phosphate cements (CPC) represent resorbable, bioactive, osteoconductive alternatives to bioinert polymethylmethacrylate cement. However, their low mechanical strength currently makes them unsuitable for the filling/treatment of bone defects in load-bearing areas, e.g. in vertebral body fractures. To improve their mechanical strength, CPC can be reinforced using fibers. The present study assessed the influence of a newly developed, fiber-reinforced, injectable CPC on bone regeneration in a minimally-invasive, in vivo vertebroplasty model in the lumbar spine of sheep.

Methods: An injectable, biodegradable, brushite-forming CPC based on a commercial cement (FDA-approved, JectOS+; Kasios, L'Union, France) with fiber reinforcement was developed for minimally-invasive surgery. The fibers (diameter 25 µm; length 1 mm) were extruded from degradable poly (l-lactide-co-glycolide) acid (PLGA) and added to the CPC (10% (w/w)). Defined bone defects (diameter 5 mm; depth approx. 1/2 of the total vertebral body width; L1 untouched; L2 empty defect; L3 pure CPC (pCPC); L4 fiber-reinforced (F-CPC)) were created by a ventrolateral percutaneous approach in aged, osteopenic, female sheep (20 Merino sheep each group; 6 - 9 years old; 68 - 110 kg body weight). Three and 9 months post-operation, structural/functional effects of the CPC on bone regeneration were documented ex vivo by osteodensitometry, static histomorphometry, micro-CT, and biomechanical testing.

Results: Both pCPC and F-CPC significantly increased the bone mineral density (pCPC > untouched (3 and 9 months); F-CPC > untouched (3 and 9 months), empty (3 months); p < 0.05). The bone volume/total volume (BV/TV; static histomorphometry) was also significantly enhanced by cement augmentation (pCPC and F-CPC > untouched and empty, 3 and 9 months). In addition, F-CPC was significantly more potent than pCPC (9 months). BV/TV analysis with µCT showed that the increase of the BV/TV by F-CPC was particularly prominent at remote distances (at 2.0 mm and 2.5 mm from the defect; 3 months). Furthermore, F-CPC significantly improved the osteoid volume (F-CPC > pCPC; 9 months) and numerically decreased the eroded surface (3 and 9 months). The compression strength was only significantly influenced by F-CPC (F-CPC > untouched and empty; 9 months).

Conclusion: F-CPC (as compared to pCPC) increases bone formation and decreases bone erosion. In particular, F-CPC enhances bone regeneration at remote distances from the defect site. Therefore, F-CPC may be superior to pCPC in bone regeneration and potentially suited for the treatment of bone defects in load-bearing areas, e.g. vertebral body fractures.