T1 Intralaminar Screws: An Anatomic, Morphologic Study of 112 Cadaveric Specimens and the Feasibility of T1 Intralaminar Screw Placement

Abstract

Laminar screw placement is generally reserved for use as a salvage or alternative technique when pedicle screw placement is contraindicated in the setting of a complex revision, tumor, or anomolous anatomy. Pedicle screws have proven to be the most biomechanically stable screws, but laminar screws are a reliable alternative when necessary. The mean pullout forces between laminar and pedicle screws are similar; however, the mean lamina screw peak insertion torque is lower than the mean index pedicle screw peak insertion torque. Advantages of laminar screw placement as opposed to pedicle screws include a decrease in possible neurovascular complications secondary to the proximity of these structures to the pedicle. Another important advantage of laminar screw fixation is that the use of a fluoroscope or navigation system is no longer necessary because the screw can be placed under direct vision of the outer cortex of the lamina and all relevant structures. Tactile feedback can also defer violation of the spinal canal.