Direct Pedicle Visualization And Disc Space Orientation As The Only Guide For Lumbar Pedicular Screw Insertion

Patients and methods: This study was conducted in Zagazig University Hospitals in the period from May 2014 to June 2015 after approval from the Zagazig University Institutional Review Board (Zu-IRB). All patients were subjected to complete history talking, clinical evaluation and adequate radiological and laboratory investigations.

The radiological studies included plain X-Ray lumbosacral spine, anteroposterior, lateral neutral, and lateral dynamic views (lateral with flexion and lateral with extension), MRI lumbosacral spine sagittal and axial views, and in some cases CT lumbosacral spine with sagittal reconstruction. All these modalities give us a good idea about both soft tissue and bony pathology in the area of interest. Selection of the patients for surgery was based on clinicoradiologic items.

All the cases of pedicular screw insertion were preceded by full laminectomy with discectomy for interbody fusion. In all cases the medial and inferior aspects of the pedicle are clearly visualized, so selection of the entry point and direct observation of medial and inferior pedicle violation are two main advantages of this technique. On the other hand after discectomy the disc space with the two parallel endplates are available for use as a guide for screw craniocaudal angulation.

After the removal of the whole lamina with its inferior articular processes and removal of fibrocartilagenous tissues overlying the exiting roots and removal of the intervertebral disc, the anatomy of the pedicle and its relation to the exiting roots is clearly evident.

Starting pedicular screw insertion, part of the cortical bone at the inferolateral edge of the superior facet is removed. This entry point lies exactly along the transverse plane passing through the middle of the corresponding transverse process.