A Biomechanical Comparison of Lateral and Posterior Approaches to Sacroplasty

Abstract

Biomechanical cadaveric bench study. To measure the augmentation effect and extravasation risk of posterior and lateral approaches to sacroplasty. The biomechanical stabilizing effect of sacroplasty is unknown. Using a sacral insufficiency fracture model, we performed sacroplasty in 15 osteoporotic cadaveric pelves. Five served as controls, and 10 were each injected with 4 mL of a polymethylmethacrylate cement (5 via a posterior approach, 5 via a lateral approach). Cement extravasation was assessed using computed tomography. Restored strength and stiffness were defined as the ratios of treatment to initial strength and to stiffness, respectively. Between-group differences in restoration parameters were checked for significance (P < 0.05) using an analysis of variance followed by Tukey's test. We found no significant differences between groups in terms of restored strength ( approximately 61%) and stiffness ( approximately 77%). Both injection methods produced extravasation into the anterior sacrum, the posterior sacrum, the sacroiliac joint, and the neural foramens. Sacroplasty with 4 mL of cement does not restore the strength or stiffness of the sacrum in a cadaveric model, regardless of the approach used.