Cervical trauma is a common cause of disability following spinal cord injury, especially in athletic populations. The biomechanics in the atlantoaxial joint carry more than 50% of the rotational movement which can be affected in transverse ligament tear associated with odontoid fracture type II. Odontoid fracture type II considered an unstable fracture with a high rate of non-union in conservative treatment. Limitation of the odontoid screws in some cases gives the chance of posterior cervical fixation to have the superior role. Use of polyaxial screws in Harms technique gives the best results in maintaining the majority of the biomechanics.

Purpose: our aim in this study to evaluate Harms technique in those patients regarding pain improvement and restoration of the motor power and to report the complications.

Study design: A retrospective case series study. We Used the Frankel grading system to evaluate the postoperative neurological state.

After approval of Research Ethics Committee, twelve patients with post-traumatic odontoid fracture type II were scheduled in our Neurosurgery department at Sohag University Hospital for atlantoaxial fusion using polyaxial C1 lateral mass and C2 pedicle screws between January 2015 and January 2018.

Inclusion Criteria:

1. C1-C2 displacement that needs intra-operative reduction
2. Short neck not suitable for anterior odontoid screw
3. Osteoporotic patients
4. Odontoid fracture associated with transverse ligament tear suspected.
5. Oblique line of fracture
6. Failure of union after conservative treatment.

Exclusion Criteria:

• Associated spinal fractures
• Other comorbidities