Biomechanical comparison of transpedicular versus extrapedicular vertebroplasty using polymethylmethacrylate.
METHODS
An in vitro biomechanical study using osteoporotic cadaveric vertebrae.


OBJECTIVE
To compare the biomechanics of transpedicular and extrapedicular approaches in polymethylmethacrylate vertebroplasty in terms of height restoration, strength, and stiffness.


BACKGROUND
Cement is typically injected through a transpedicular approach in both vertebroplasty and kyphoplasty procedures. Previous biomechanical studies were primarily focused on the transpedicular approach. Extrapedicular approach has been recently developed to provide more symmetric cement filling and has good clinical results. However, no biomechanical data are available to compare these 2 techniques.


METHODS
Twenty-four osteoporotic vertebral bodies were randomly divided into 2 groups for either transpedicular or extrapedicular vertebroplasty. Six lumbar and 6 thoracic vertebrae were used for each group. Each vertebral body was compressed by 25% of its original height and its strength and stiffness were measured. The vertebral bodies were treated with polymethylmethacrylate using either transpedicular or extrapedicular approach. The height restoration was measured before the treated vertebrae were recompressed to determine posttreatment strength and stiffness.


RESULTS
Both techniques increased vertebral strength by approximately 50% of the intact strength. There was no statistical difference in posttreatment strength between these 2 techniques. However, the transpedicular technique had higher stiffness recovery (70% to 80%) from the intact stiffness than the extrapedicular technique (60%). The extrapedicular approach achieved greater height restoration in thoracic vertebrae.


CONCLUSIONS
Both extrapedicular and transpedicular techniques increased strength but reduced stiffness compared with the intact condition. The extrapedicular technique achieved greater height restoration possibly attributed to its easier access to the fracture site. These biomechanical data provide useful information when selecting an approach for cement injection in vertebroplasty procedures.
Erkan
Serkan
S
Department of Orthopaedics, School of Medicine, Celal Bayar University, Manisa, Turkey.
Wu
Chunhui
C
Mehbod
Amir A
AA
Cho
Woojin
W
Transfeldt
Ensor E
EE
D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D001843:Bone Cements / Q000627:therapeutic use; D019245:Compressive Strength; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D010024:Osteoporosis / Q000503:physiopathology / Q000601:surgery*; D019904:Polymethyl Methacrylate / Q000627:therapeutic use*; D013314:Stress, Mechanical; D013904:Thoracic Vertebrae / Q000503:physiopathology / Q000601:surgery*; D054854:Vertebroplasty; D016474:Weight-Bearing
D001843:Bone Cements; D019904:Polymethyl Methacrylate