[Pedicle lag screw for the treatment of indicated Hangman fractures]

To define the indication of C2 pedicle lag screw to treat Hangman fractures and evaluate its results.

Twenty-eight patients with Hangman fractures were enrolled from July 2003 to June 2007. Six, 17 and 5 patients classified as type I , II and IIa injuries respectively according to Levine-Edwards classification and graded as D spinal injury in 3 cases and E in 7 cases according to Frankel scale. The entry points of screws were located at middle point of lateral mass. The direction of screw is determined based on the direction of the medial and superior border of C2 pedicle, usually 25 degrees to 30 degrees cephalad to the transverse plane and 30 degrees to 35 degrees medial to the sagittal plane. The length of screws range from 24 to 30 mm.

There were no vertebra artery injuries or other complications during the operation. A mean follow-up time was 20 months (4 to 48 months). All cases gained bony union at the 6th postoperative month with complete neurological function recovery. The range of neck rotation was restored normal without cervicle spinal instability and lag screws loosing found.

Single segmental pedicle lag screw internal fixation provides instantly stability to Hangman fracture and scarcely affects the physiological functions of upper cervicle spine. With appropriate indications of the techniques should be reducible Hangman fracture.