ABSTRACT

Aim:

The objective of the study is to determine the safe and reliable area in thoracic spine that application of intrapedicular screw is difficult.

Materials and Methods:

A study group is constituted 42 adults (21 men, 21 women) who have no medical history about thoracic spine. The mean age was 36.7(16-56) years old. True axial cross sections passing through both pedicles between T1 to T12 were taken with MRI. On these MRI cross sections, width of transverse intraosseous pedicle, width of transverse intraosseous (Pedicle Rib Unit) PRU, length of pedicle screw path, length of PRU screw path, relation of pedicle screw path with aorta and relation of PRU screw path with aorta were measured with the help of a computer programme.

Results:

A statistically significant difference was found on each level between the transverse intraosseous width of pedicle and those of PRU, and length of pedicle screw path and those of PRU. While injury risk for aorta is high on the left side when the conventional pedicle screw path is used, it is high on the right side when PRU screw path is used.

Conclusions:

When we compared PRU screw path with those of conventional pedicle screw path in point of neurological injury risk; PRU screwpath provide us to keep away from epidural space. On the contrary, the injury risk of aorta is high at the right side PRU screw path used and is high at the left side when the conventional pedicle screw path used. Hybrid application (the using of PRU screw path at the left side and the using of conventional screw path at the right side) may minimize both neurological and aortic injury risk when the pedicle width is adequate.