Biomechanical evaluation of calcium phosphate-based nanocomposite versus polymethylmethacrylate cement for percutaneous kyphoplasty

• Published in: The spine journal 2019-11, Vol.19 (11), p.1871-1884
• Main Authors: Lu, Qifeng, Liu, Chun, Wang, Dingsong, Liu, Huiling, Yang, Huilin, Yang, Lei
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Animals; Biomechanical Phenomena; Biomechanics; Bone Cements - chemistry; Bone Cements - therapeutic use; Cadaver; Calcium phosphate; Calcium Phosphates - chemistry; Calcium Phosphates - therapeutic use; Cement leakage; Female; Fractures, Compression - diagnostic imaging; Fractures, Compression - surgery; Humans; Kyphoplasty; Kyphoplasty - methods; Male; Minimally invasive surgery; Nanocomposite; Nanocomposites - chemistry; Osteoporosis; Osteoporotic Fractures - diagnostic imaging; Osteoporotic Fractures - surgery; Polymethyl Methacrylate - chemistry; Polymethyl Methacrylate - therapeutic use; Polymethylmethacrylate; Postoperative Complications; Sheep; Spinal Fractures - diagnostic imaging; Spinal Fractures - surgery; Tomography, X-Ray Computed; Vertebral compression fracture; Viscosity
• ISSN: 1529-9430; 1878-1632
• DOI: 10.1016/j.spinee.2019.06.007

Polymethylmethacrylate (PMMA) is the most commonly used filling material when performing percutaneous kyphoplasty (PKP) for the treatment of osteoporotic vertebral compression fractures. However, there are some inherent and unavoidable drawbacks with the clinical use of PMMA. PMMA bone cement tends to leak during injection, which can lead to injury of the spinal nerves and spinal cord. Moreover, the mechanical strength of PMMA-augmented vertebral bodies is extraordinary and this high level of mechanical strength might predispose to adjacent vertebral fractures. A novel biodegradable calcium phosphate-based nanocomposite (CPN) for PKP augmentation has recently been developed to potentially avoid these issues. By comparison with PMMA, the leakage characteristics, biomechanical properties, and dispersion of CPN were evaluated when used for PKP. Biomechanical evaluation and studies on the dispersion and anti-leakage properties of CPN and PMMA cements were performed and compared using cadaveric vertebral fracture model, sheep vertebral fracture model, and simulated rigid foam model. Sheep vertebral bodies were decalcified by ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) to simulate osteoporosis in vitro. After compression to create wedge-shaped fractures using a self-designed fracture creation tool, human cadaveric vertebrae and decalcified sheep vertebrae were augmented by PKP. In addition, three L5 vertebral bodies from human cadavers were used in a contrast vertebroplasty (VP) augmentation experiment. Occurrence of cement leakage was observed and compared between CPN and PMMA during the process of vertebral augmentation. Open-cell rigid foam model (Sawbones#1522-507) was used to create a simulated leakage model for the evaluation of the leakage characteristics of CPN and PMMA with different viscosities. The augmentation effects of CPN and PMMA were evaluated in human cadaveric and decalcified sheep vertebral models and then compared to the results from solid rigid foam model (Sawbones#1522-23). The dispersion abilities of CPN and PMMA were evaluated via three methods as follows. The dispersion volume and dispersion ratio were calculated by three-dimensional reconstruction using human vertebral body CT scans; the ratio of cement area to injection volume was calculated from three-dimensional sections of micro-CT scans of a sheep vertebra; and the micro-CT images of cement dispersion in open-cell rigid foam model (Sawbones#1522-507) were compared bet