Biomechanical in vitro testing of human osteoporotic lumbar vertebrae following prophylactic kyphoplasty with different candidate materials.
METHODS
Biomechanical study of human osteoporotic lumbar vertebrae following prophylactic kyphoplasty.


OBJECTIVE
To evaluate the potential benefits of different resorbable candidate materials for use in prophylactic kyphoplasty compared with the behavior of polymethylmethacrylate cement.


BACKGROUND
Kyphoplasty using PMMA bone cement for the stabilization of fractured osteoporotic vertebrae has been established as a useful clinical tool. In several studies, consecutive compression fractures have been reported in vertebrae caudal or cranial to those augmented with bone cement. Consequently, some physicians have begun to treat adjacent vertebrae by means of prophylactic augmentation.


METHODS
Biomechanical in vitro testing was performed on 40 human osteoporotic nonfractured lumbar vertebrae. Three types of bone cement (PMMA, 2 different calcium phosphate cements) and one silicon derivative were assessed during compressive and cyclic sinusoidal testing. Each candidate material was applied bipedicularly under fluoroscopic control.


RESULTS
Differing processing qualities of the materials led to substantial differences during cement injection, in particular in the amount of cement filling of the vertebrae. However, in comparison to native vertebrae, augmented specimens showed significantly higher compressive failure. No significant differences between vertebral bodies treated with PMMA and those treated with either type of calcium phosphate cement were documented. The biomechanical properties of the vertebrae could not be significantly improved by the silicon derivative.


CONCLUSIONS
This study demonstrated that calcium phosphate cements displayed identical behavior to PMMA cement with respect to in vitro mechanical qualities. Consequently, from a mechanical viewpoint, calcium phosphate cements may be used in addition to PMMA cement for kyphoplasty and prophylactic kyphoplasty. Silicon derivatives are apparently not recommendable as candidate materials for kyphoplasty.
Rotter
Robert
R
Department of Trauma & Reconstructive Surgery, University of Rostock, Rostock, Germany.
Pflugmacher
Robert
R
Kandziora
Frank
F
Ewert
Andreas
A
Duda
Georg
G
Mittlmeier
Thomas
T
D000368:Aged; D000369:Aged, 80 and over; D001843:Bone Cements; D002130:Calcium Phosphates; D019245:Compressive Strength; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007738:Kyphosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D019904:Polymethyl Methacrylate; D012825:Silicon; D014057:Tomography, X-Ray Computed; D016474:Weight-Bearing
D001843:Bone Cements; D002130:Calcium Phosphates; D019904:Polymethyl Methacrylate; C020243:calcium phosphate; D012825:Silicon