Biomechanical analysis of sacroplasty: does volume or location of cement matter?

BACKGROUND AND PURPOSE: Currently, the effect of the volume of cement used during sacroplasty on the restoration of pelvic strength and stiffness is unknown. The purpose of this study was to measure that effect in a sacral insufficiency fracture model.

MATERIALS AND METHODS: Twenty-five osteoporotic cadaveric pelves were potted, and sacral fractures were produced. Specimens were divided into 4 groups: group 0 + 0 (control), no sacroplasty; group 3 + 0, sacroplasty (posterior approach), 3 mL of a bone cement injected bilaterally into the fracture site at S1; group 3 + 3, sacroplasty (posterior approach), 3 mL of the same cement injected bilaterally into the fracture site at S1 and S2; and group 6 + 3, sacroplasty (posterior approach), 6 mL of the same cement injected bilaterally at S1 and 3 mL injected bilaterally at S2. Cement position and extravasation were documented with CT. Specimens were tested to failure to assess the strength and stiffness after sacroplasty.

RESULTS: There were no significant differences in strength or stiffness restoration between control and treatment groups.

CONCLUSIONS: Sacroplasty does not restore the strength or stiffness of the sacrum in a cadaveric model regardless of the volume or location of cement.