Anatomic comparison of the Roy-Camille and Magerl techniques for screw placement in the lower cervical spine.

The Roy-Camille and Magerl techniques for screw placement in the lower cervical spine were compared under simulated operating room conditions. Three surgeons with varying years of spine surgery experience participated. The anatomic morbidity risks of each screw insertion technique were evaluated by anatomic dissection and radiographic examination. The spinal cord and vertebral arteries were not threatened by either method. Analysis of the pooled data revealed that the Roy-Camille technique had less risk of nerve root injury, nerve roots placed "at risk" for injury, and errors in "zone" of placement. The Magerl technique had less risk of facet joint violation. A learning curve was observed. Once the surgeons gained experience with the two techniques, there were no longer any statistically significant differences among them. The number of years of spine surgery practice did not influence the morbidity risk of either technique. The surgeons' ability to aim the screws was identical in the axial plane, but consistently less accurate in the sagittal plane for the Magerl screws because of the normal prominence of the cervicothoracic junction. Thorough familiarity with the regional anatomy and practice in the anatomy laboratory are recommended before performing these techniques in patients.