The use of small malleable endoscopes to assess pedicle screw placement: technical note

Because the improper insertion of pedicle screws can be associated with significant neurologic morbidity, attempts are being made to improve on the accuracy of pedicle screw placement. As a possible strategy we have studied the use of small malleable endoscopes to explore the pedicle and exiting nerve root during and after pedicle screw placement. These small endoscopes are 1.2 mm in diameter and can be bent so that the superior, medial and inferior walls of the pedicle can be visualized. Additionally, the nerve roots superior to and inferior to the pedicle can be seen throughout their entire intraspinal course. Using these endoscopes in ten patients requiring the placement of forty-four pedicle screws we were able to visualize the pedicles and nerve roots in all cases. The endoscope demonstrated that one screw had penetrated the inferior cortex of the pedicle. This penetration was not palpable with blind probing of the pedicle and foramina. These cases suggest that this simple technique may be of use in limiting improper pedicle screw placement.