gms | German Medical Science

Objective: In order to optimize and standardize our institutional performance we implemented image-guidance as routine for placement of odontoid lag-screws, C2 isthmic-, C1 lateral mass- and pedicle screws in the cervical- and upper thoracic spine. We here summarize our experience following the introduction of the techniques in 2012.

Method: Following introduction of the navigated technique (upper cervical spine in 01/2012, and lower cervical/upper thoracic spine in 07/2012) patients presenting with instabilities of the cervical and upper thoracic spine were scheduled for image-guided screw implantation. For the upper cervical spine (ventral and dorsal approach) we used 3D C-Arm registration (Arcadis-Orbic, Siemens) in combination with the KolibriR (BrainLab), while lower cervical- and upper thoracic pedicle screws were implanted using landmark registration and the KolibriR (BrainLab). Applied screw systems included Weber-Schultheiss odontoid lag-screws (Synthes) for ventral C2 instrumentation, Kleinfragment Titan spongiosa lag-screws (Synthes) for isolated C2 isthmic fractures, and Vertex (Medtronic), Lineum (Biomet) and Viper2 (Depuy-Synthes) poly-axial screw systems for dorsal instrumentation of one or more segments. Navigated screws were frequently combined with non-navigated lateral mass-screws in the levels C3-C6.

Results: 53 consecutive patients presenting with instabilities involving the cervical and upper thoracic spine underwent image-guided dorsal instrumentation with 67 pedicle screws, 50 C2-isthmic screws and 34 C1 lateral mass screws, as well as ventral instrumentation with 7 odontoid lag-screws. 1 pedicle screw and 2 isthmic screws had to be revised because of screw misplacement without causing neurological deficit. 1 patient had a transient C2 hypaesthesia, 1 patient died because of a vertebral artery involvement and possible compression of the artery by a C1 screw head (in presence of a fractured C1 arch). 2 odontoid screws showed signs of screw loosening and pseudoarthrosis during follow-up and in 1 case the ventral odontoid lag-screw could not be placed because of a screw system-related technical problem. The latter three cases received C1 lateral mass/C2 isthmic screws in a second operation.

Conclusions: The applied image-guidance techniques were found to be reliable and easy to handle for the implantation of odontoid lag-screws, C2 isthmic-, C1 lateral mass- and pedicle screws in the cervical- and upper thoracic spine.