MATERIAL and METHODS: Data from 72 consecutive patients with spinal instability that received 472 screws between April 2011 and May 2013 were reviewed and pedicle wall breach was graded as mild (< 3 mm), moderate (3-6 mm) and severe (> 6 mm). Direction of misplacement was also assessed in reformatted images as medial, lateral, superior and inferior (or in combinations).

RESULTS: The indications for pedicle screw placement were as follows: degenerative (59.7%), trauma (13%) and tumor (9.7%). Pedicle screws were inserted between T9 and S1. In this series of the 472 screws, 29 (6.1%) screws were implanted with minimal pedicle wall violation (≤3mm) and 16 screws (3.4%) were implanted with moderate (3-6 mm) violations. There were no severe violations (more than 6 mm) in this series. Pedicle violations were significantly higher in thoracic pedicles and in trauma patients when compared to other groups. Only two patients required pedicle screw repositioning after their index surgery.

CONCLUSION: Conventional open technique in pedicle screw placement is a safe and sound method with its low and acceptable complication rates Keywords : Open pedicle screw positioning, Pedicle breach, Pedicle screw, Pedicle screw malposition, Spinal instability, Thoracolumbar instability