Improved biomechanics of two alternative kyphoplasty cementation methods limit vertebral recollapse

Biomechanical Comparisons between One- and Two-Compartment Devices for Reconstructing Vertebrae by Kyphoplasty

BACKGROUND

This biomechanical in vitro study compared two kyphoplasty devices for the extent of height reconstruction, load-bearing capacity, cement volume, and adjacent fracture under cyclic loading.

METHODS

Multisegmental (T11-L3) specimens were mounted into a testing machine and subjected to compression, creating an incomplete burst fracture of L1. Kyphoplasty was performed using a one- or two-compartment device. Then, the testing machine was used for a cyclic loading test of load-bearing capacity to compare the two groups for the amount of applied load until failure and subsequent adjacent fracture.

RESULTS

Vertebral body height reconstruction was effective for both groups but not statistically significantly different. After cyclic loading, refracture of vertebrae that had undergone kyphoplasty was not observed in any specimen, but fractures were observed in adjacent vertebrae. The differences between the numbers of cycles and of loads were not statistically significant. An increase in cement volume was strongly correlated with increased risks of adjacent fractures.

CONCLUSION

The two-compartment device was not substantially superior to the one-compartment device. The use of higher cement volume correlated with the occurrence of adjacent fractures.

Should kyphoplasty curettes be used in nonosteoporotic patients? A cautionary tale

The authors present the first report of a fracture of the tip of a kyphoplasty curette inside the vertebral body, which occurred during a procedure in a patient with non-osteoporotic fracture. This highlights the need of further biomechanical research focused on the shear load failure properties of such type of pre-bent curettes.