Intrabody application of eptotermin alpha enhances bone formation in osteoporotic fractures of the lumbar spine; however, fails to increase biomechanical stability – results of an experimental sheep model

Abstract

This study analyses the effect of eptotermin α application into fractured vertebrae. It is hypothesized that eptotermin α is capable to enhance bony healing of the osteoporotic spine. In 10 Merino sheep osteoporosis induction was performed by ovariectomy, corticosteroid therapy and calcium/phosphorus/vitamin D-deficient diet; followed by standardized creation of lumbar vertebral compression fractures (VCFs) type A3.1 and consecutive fracture reduction/fixation using expandable mesh cages. Randomly, intravertebral eptotermin α (G1) or no augmentation was added (G2). Macroscopic, micro-CT, and biomechanical evaluation assessed bony consolidation two months postoperatively: Micro-CT data revealed bony consolidation for all cases with significant increased callus development for G2 (60%) and BV/TV (bone volume/total volume 73.45%, osteoporotic vertebrae 35.76%). Neither group showed improved biomechanical stability. Eptotermin α enhanced mineralisation in VCFs in an experimental setup with use of cementless augmentation via an expandable cage. However, higher bone mineral density did not lead to superior biomechanical properties.

• Eptotermin α
• micro-CT
• osteoporosis
• sheep model
• rhBMP-7
• vertebral burst fracture

Acknowledgements

The authors thank Reinhard Schwärmer, Klaus-Dieter Russow and the entire staff of the Institute for Experimental Surgery for their valuable assistance with animal handling and surgery. We also wish to express gratitude to Dr. Sven Grumbach for his invaluable organizational assistance and Mr. Hartmund Münch and his team for assistance in animal care. Furthermore, we would like to thank Dr. Martin Reichel and his team for assistance in biomechanical testing.

Declaration of interest

This study was financially supported by Olympus Biotech International and Alphatec Spine; the senior author GG is related with speaker and teaching activities to the latter company. The remaining authors declare that they have no conflict of interest.