Does bone cement in percutaneous vertebroplasty act as a stress riser?

Area of Science:

• Spinal surgery
• Orthopedic biomechanics
• Vertebral augmentation

Background:

• Concerns exist that percutaneous vertebroplasty (PVP) may cause stress peaks in adjacent vertebrae, potentially leading to new fractures.
• Previous in vitro studies suggesting this risk used larger bone cement volumes than typically used clinically.

Purpose of the Study:

• To investigate whether PVP with clinically relevant bone cement volumes induces stress peaks in adjacent vertebrae.
• To evaluate the biomechanical effects of PVP on vertebral strength and stiffness.

Main Methods:

• An in vitro cadaveric study involving ten fresh-frozen vertebrae.
• Vertebrae were loaded to failure, with force, displacement, and sub-endplate pressure recorded.
• Following augmentation with clinically relevant bone cement volumes, vertebrae were reloaded to failure to assess changes.

Main Results:

• Stress peaks were not correlated with the location of injected bone cement.
• Vertebral failure load and stiffness were significantly reduced after augmentation with bone cement.

Conclusions:

• Vertebral augmentation with clinically relevant bone cement volumes does not appear to cause stress peaks under the endplate.
• PVP, when performed with appropriate cement volumes, is unlikely to be the direct cause of detrimental stresses leading to adjacent vertebral fractures.