Techniques of cervical pedicle screw insertion in lower cervical spine - A review

Cervical pedicle screws (CPS) have been used for stabilization of lower cervical spine since its first description by Abumi et al., in 1994^, but the usage has been limited due to the feared complications. Cadaveric studies have discouraged use of CPS in lower cervical spine due to high misplacement rates. On the contrary, clinical studies have shown limited complications due to screw misplacements and have highlighted the benefits of CPS with its superior biomechanical strength. Therefore surgeons have always tried to find a reliable, reproducible and safe CPS insertion technique to expand the usage of CPS with minimal complications. As of today Abumi et al. technique is the most popular free-hand technique used by surgeons, though many modifications have evolved to make the CPS insertions more safe and reproducible. The free hand technique should be considered as the cornerstone technique for CPS insertion and the navigation tools are essential to improve the safety of CPS in complex surgeries with altered cervical anatomy. The present review brings together the literature on the various aspects of cervical pedicle anatomy, the free-hand screw insertion techniques with their modifications, the screw misplacement rates and complications.