Trabecular Microstructure and Damage Affect Cement Leakage From the Basivertebral Foramen During Vertebral Augmentation.

STUDY DESIGN: A prospective study on cadaver specimens.

OBJECTIVE: To explore why cement leakage from basivertebral foramen (BF) easily occurs during vertebral augmentation procedures.

SUMMARY OF BACKGROUND DATA: Type B (through BF, basivertebral foramen) cement leakage is the most common type after vertebral augmentation, but the mechanism of this is still controversial. The contribution of vertebral trabecular bone orientation and trabecular damage during compression fracture to cement leakage is still unknown.

METHODS: In this study, 12 fresh-frozen human lumbar spines (T12-L5) were collected and divided into 24 three-segment units. Mechanical testing was performed to simulate a compression fracture. MicroCT were performed on all segments before and after mechanical testing, and trabecular microstructure of the superior, middle (containing BF), and inferior 1/3 of each vertebral body was analyzed. The diameter variation of intertrabecular space before and after compression fracture was used to quantify trabecular injury. After mechanical testing, vertebral augmentation, and imaging-based diagnosis were used to evaluate cement leakage.

RESULTS: Trabecular bone microstructural parameters in middle region (containing BF) were lower than those of the superior or inferior regions (P < 0.01). After compressive failure, 3D-reconstruction of the vertebral body by MicroCT demonstrated that intertrabecular distance in the middle region was markedly increased. Type B cement leakage was the most common type after vertebral augmentation, as found previously in Wang et al. (Spine J 2014;14: 1551-1558).

CONCLUSION: The presence of the BF and the relative sparsity of trabecular bone make the middle region of the vertebral body the mechanically weakest region. Trabecular bone in middle region suffered the most severe damage during compressive failure of the vertebral body, which resulted in the greatest intervertebral spacing, and subsequently the highest percentage of type B cement leakage. These data suggest specific mechanisms by which cement may leak from the BF, and the contribution of trabecular microstructure and trabecular injury.

LEVEL OF EVIDENCE: 4.