The expansion behavior of human lumbar pedicle cortex
SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2006, Saint Louis, MO, Amerika Birleşik Devletleri, 4 - 07 Haziran 2006, cilt.1, ss.214-219, (Tam Metin Bildiri)
- Yayın Türü: Bildiri / Tam Metin Bildiri
- Cilt numarası: 1
- Basıldığı Şehir: Saint Louis, MO
- Basıldığı Ülke: Amerika Birleşik Devletleri
- Sayfa Sayıları: ss.214-219
- Trakya Üniversitesi Adresli: Evet
Özet
Pedicle screws are commonly used to provide support for a fractured spine during healing process. However, neither the microstructure of pedicle nor the maximum screw size that will not cause any fracture at the pedicle is clearly known. Four human lumbar vertebral specimens yielding eight pedicles were obtained. Two linear strain gauges were circumferentially affixed to the lateral and medial surfaces. 6.5×45mm and 7.5×40mm pedicle screws were sequentially placed into each pedicle and removed carefully. Lateral and medial cortices of several intact lumbar pedicles were sectioned and images of cortex cross-sections were analyzed under microscope. Deformations at the cortices produced during screw insertion could not be restored after removal although no visible fracture was detected. Strain levels producing plastic deformation in the pedicle cortex were different from those reported for femoral cortical bone. The image analyses showed that the pedicle cortex had an osteonal structure. However, no surrounding lamellar bone was observed at the periosteum. Our results suggested that screw insertion into the pedicle caused plastic deformation although the screws did not contact the cortex. The structure and mechanical properties of the pedicle cortex seemed to be different from those of other cortical bones in human body.