Mechanism of fractures of adjacent and augmented vertebrae following simulated vertebroplasty
Journal
Journal of Biomechanics
Journal Volume
45
Journal Issue
8
Pages
1372-1378
Date Issued
2012
Author(s)
Abstract
Percutaneous vertebroplasty (VP) is a minimally invasive procedure that is used to treat osteoporosis-induced vertebral compression fractures (OVCFs). Frequently observed complications are fractures of adjacent and augmented vertebrae. In the present work, mechanisms for these fractures are presented. Fresh 4-level osteoporotic thoracic motion segments were tested. Both ends of the specimen were mounted. The lower level of the free vertebra was compressively fractured and followed by an injection of a 3.5. mL of a PMMA bone cement. Three steps of fatigue loading (5. Hz for 5. h) were incrementally and vertically applied on the specimens from 650. N to 950. N to 1150. N. Specimens of intact, compressively fractured, cement augmented and post-fatigued loading were radiographed for the measurement of deformations of the vertebra, the canal, and the foramen. At the end of fatigue loading, the vertebrae were sliced for micro morphologic analysis. The largest height loss after fatigue loading was at the posterior region of the augmented vertebra. In the augmented vertebra, fissures were found along the bone-cement interface. These fissures split the cement and the trabeculae and propagated into the vertebrae and the endplates. The compactness ratio of the trabeculae region of the adjacent cranial vertebra was higher than that for intact and adjacent caudal ones. We attribute the fracture of the augmented vertebra, following simulated VP, to the initiation of fissures along the cement-bone interface, which, in turn, may be due to uneven deformation of the vertebra. Fracture of the adjacent cranial vertebra is attributed to collapse of its trabeculae. ? 2012 Elsevier Ltd.
Subjects
Fatigue loading; PMMA bone cement; Vertebral fracture; Vertebroplasty
SDGs
Other Subjects
4-level; Bone-cement interface; Endplates; Fatigue loadings; Minimally invasive; Morphologic analysis; Motion segments; Osteoporotic; Percutaneous vertebroplasty; PMMA bone cement; Vertebral compression; Vertebral fractures; Vertebroplasty; Bone cement; Cements; Deformation; Fracture; Loading; Musculoskeletal system; bone cement; adult; aged; article; compression fracture; controlled study; disease activity; fatigue; female; human; loading test; male; micromorphology; morphological trait; nerve ending; osteoporosis; percutaneous vertebroplasty; priority journal; trabecular bone; vertebra body; vertebra fracture; Adult; Aged; Aged, 80 and over; Elastic Modulus; Female; Humans; Male; Middle Aged; Osteoporotic Fractures; Tensile Strength; Thoracic Vertebrae; Vertebroplasty; Weight-Bearing
Type
journal article