Cervical Pedicle Screw Fixation: Anatomic Feasibility of Pedicle Morphology and Radiologic Evaluation of the Anatomical Measurements

STUDY DESIGN: All parameters were measured manually and with a computed tomography (CT) scanner. For the manual measurements, a Vernier scale instrument was used. PURPOSE: This study evaluates quantitatively pedicles of middle and lower cervical spine (C(3) to C(7)) and to evaluate the possibilities of using these structures as anchors in posterior cervical fusion. OVERVIEW OF LITERATURE: Pedicle screws may be an alternative fixation technique for posterior cervical instrumentation. METHODS: Twenty-two bony sets of adult cervical spines were studied (110 vertebrae, 220 pedicles) from C(3) down to C(7). RESULTS: CT measurement of cervical pedicles appeared to be accurate and valuable for preoperative planning of cervical pedicle screw instrumentation. The study showed a high correlation between the values obtained by manual and CT measurements of pedicle dimensions. The technical challenge of insertion is the obvious theoretical drawback of the use of cervical pedicle screws. Many technical factors are important to consider, namely, the point of screw entry, the pedicle dimensions, the screw direction according to the pedicle angle and orientation, the screw diameter and length, and the method of screw introduction. CONCLUSIONS: Transpedicular screw fixation of the cervical spine appears to be promising. Anatomic limitations should be clear to the surgeon. Further clinical and biomechanical studies are needed to settle this technique.