Table 1.

Radiological assessment of cervical pedicle screw placement (94 screws)

Correct position: 66 screws=70%
Screw completely within cortical walls of the pedicle	46 screws
Cortical perforation maximum of 1 mm in CT	20 screws

Minor breach: 20 screws=21%
Lateral or ventral perforation of the vertebral body	5 screws
Slightly affecting the lateral recess without dural contact	10 screws
Narrowing of the vertebral channel less than 25%	5 screws

Major breach: 8 screws=9%
Medial perforation of the pedicle with dural tear	0 screws
Medial perforation with radicular/medullar compression	0 screws
Caudal perforation with potential nerve root injury	3 screws
Narrowing of the vertebral channel more than 25%	5 screws