Biomechanical Study of Porcine Osteoporotic Vertebral Compression Fracture Model Strengthened by Trajectory-Adjustable Bone Cement Filling Device

Abstract

Objective: To establish a porcine osteoporotic vertebral compression fracture model and compare the impact of unilateral vertebroplasty using trajectory-adjustable bone cement filling device to traditional surgical tools on vertebral biomechanics.

Methods: Twenty-four fresh adult porcine vertebrae were used to establish an osteoporotic vertebral compression fracture model. The specimens were divided into 4 groups (A, B, C, and D), each consisting of 6 vertebrae. Group A served as the control group without vertebral augmentation (percutaneous vertebroplasty [PVP]). Patients in Group B underwent unilateral PVP using conventional surgical tools, while patients in Group C underwent bilateral PVP using the same tools. In Group D, patients underwent unilateral PVP with a trajectory-adjustable bone cement filling device. Postoperative X-ray examinations were performed to assess cement distribution and leakage. The compressive stiffness and strength of each spinal unit were evaluated using an electronic mechanical testing machine.

Results: In Groups B, C, and D, the percentages of total cement distribution area were 32.83 ± 3.64%, 45.73 ± 2.27%, and 47.43 ± 3.51%, respectively. The values were significantly greater in Groups C and D than in Group B (P < 0.05), but there was no significant difference between Groups C and D (P > 0.05). The stiffness after vertebral augmentation in Groups B, C, and D was 1.04 ± 0.23 kN/mm, 1.11 ± 0.16 KN/mm, and 1.15 ± 0.13 KN/mm, respectively, which were significantly greater than that in Group A (0.46 ± 0.06 kN/mm; P < 0.05). The ultimate compressive strengths in Groups B, C, and D were 2.53 ± 0.21 MPa, 4.09 ± 0.30 MPa, and 3.99 ± 0.29 MPa, respectively, all surpassing Group A's strength of 1.41 ± 0.31 MPa. Additionally, both Groups C and D demonstrated significantly greater ultimate compressive strengths than Group B did (P < 0.05).

Conclusions: A trajectory-adjustable bone cement filling device was proven to be an effective approach for unilateral vertebroplasty, restoring the biomechanical properties of fractured vertebrae. Compared to traditional surgical tools, this approach is superior to unilateral puncture and yields outcomes comparable to those of bilateral puncture. Additionally, the device ensures a centrally symmetrical distribution pattern of bone cement, leading to improved morphology.

Keywords: Biomechanics; Bone cement distribution; Osteoporotic vertebral compression fracture; Porcine vertebrae; Trajectory-adjustable; Vertebroplasty.