A biomechanical investigation of vertebroplasty in osteoporotic compression fractures and in prophylactic vertebral reinforcement.
METHODS
Cadaveric single vertebrae were used to evaluate vertebroplasty as a prophylactic treatment and as an intervention for vertebral compression fractures.


OBJECTIVE
To investigate the biomechanical characteristics of prophylactic reinforcement and postfracture augmentation of cadaveric vertebrae.


BACKGROUND
Percutaneous vertebroplasty is a treatment option for osteoporotic vertebral compression fractures. Short-term results are promising, but longer-term studies have suggested a possible accelerated failure rate in the adjacent vertebral body. Limited research has been conducted into the effects of prophylactic vertebroplasty in osteoporotic vertebrae. This study aims to elucidate the biomechanical differences between the 2 treatment groups.


METHODS
Human vertebrae were assigned to 2 scenarios: Scenario 1 simulated a wedge fracture followed by cement augmentation; Scenario 2 involved prophylactic augmentation using vertebroplasty. Micro-CT imaging was performed to assess the bone mineral density, vertebral dimensions, fracture pattern, and cement volume. All augmented specimens were then compressed under an eccentric flexion load to failure.


RESULTS
Product of bone mineral density and endplate surface area gave a good prediction of failure strength when compared with actual failure strength of specimens in Scenario 1. Augmented vertebral bodies showed an average cement fill of 23.9% +/- 8.07%. There was a significant postvertebroplasty increase in failure strength by a factor of 1.72 and 1.38 in Scenarios 1 and 2, respectively. There was a significant reduction in stiffness following augmentation for Scenario 1 (t = 3.5, P = 0.005). Stiffness of the vertebral body in Scenario 2 was significantly greater than observed in Scenario 1 (t = 4.4, P = 0.0002).


CONCLUSIONS
Results suggest that augmentation of the vertebrae postfracture significantly increases failure load, while stiffness is not restored. Prophylactic augmentation was seen to increase failure strength in comparison to the predicted failure load. Stiffness appears to be maintained suggesting that prophylactic vertebroplasty maintains stiffness better than vertebroplasty postfracture.
Furtado
Navin
N
School of Mechanical Engineering, University of Leeds, Leeds, UK.
Oakland
Robert J
RJ
Wilcox
Ruth K
RK
Hall
Richard M
RM
D000369:Aged, 80 and over; D001843:Bone Cements / Q000627:therapeutic use*; D015519:Bone Density; D002102:Cadaver; D019245:Compressive Strength; D004548:Elasticity; D005260:Female; D050815:Fractures, Compression / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control* / Q000601:surgery*; D006801:Humans; D019637:Orthopedic Procedures; D010024:Osteoporosis / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011859:Radiography; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control* / Q000601:surgery*; D013131:Spine / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D017211:Treatment Failure; D016474:Weight-Bearing
D001843:Bone Cements