Author/Authors :
Habib-Allah -Zadeh, P. Department of Orthopedic - Sina Hospital - School of Medicine - Tehran University of Medical Sciences - Tehran, Iran , Mirzashahi, B Department of Orthopedic - Sina Hospital - School of Medicine - Tehran University of Medical Sciences - Tehran, Iran , Sadat, M. M. Department of Orthopedic - Sina Hospital - School of Medicine - Tehran University of Medical Sciences - Tehran, Iran , Siavashi, B Department of Orthopedic - Sina Hospital - School of Medicine - Tehran University of Medical Sciences - Tehran, Iran , Mohammad-Hosseini, S. Mechanic Engineering - Sharif Industrial University of Tehran, -Tehran, Iran , Ziaei-Moayyed, A.A Department of Material Engineering - Sharif Industrial University of Tehran - Tehran, Iran
Abstract :
Pedicle screws provide rigid fixation for instabilities in the lumbar and lumbosacral spine.
Anatomical consideration and potential risk of neurologic complications are the reasons to hesitate
using pedicle screws in the thoracic spine. Twenty moulages similar to human vertebrae were
instrumented with Cotrel-Dubousset (CD) system pedicle screw by intratransverse process,
extrapedicular and intrapedicular methods and pullout strength was measured. There was statistically
significant difference between three techniques. By increasing the length of screw in any method,
pullout strength increased. Average pullout strength in extrapedicular technique was less than two other
techniques in dynamic state. The strongest technique for screw placement was intratransverse process
technique. It seems that intratransverse process technique is safe for posterior fixation of spine.
Keywords :
pullout strength , intratransverse process , thoracic , screw spine , Pedicle
