Atlantoaxial Rotatory Fixation: New Diagnostic Paradigm And A New Classification Based On Motion Analysisi Using Computed Tomographic Imaging CGMH Chia Ni, Lin

Contents AARF Anatomy Patients and Method Result Discussion

Atlantoaxial Rotatory Fixation (AARF) The unique configuration of the atlantoaxial complex lends itself to behave as the main rotational pivot of the cervical spine often painful, rotational deformity that we call atlantoaxial rotatory fixation (AARF) because of its apparent “ fixed ” state to voluntary or involuntary correction. typically present with torticollis with the head in the “ cock-robin ” position

Anatomy

The predictable relationship between C1 and C2 single motion phase (from C1° = 0 to 23°), when only C1 turns double motion phase (from C1° = 24 to 65°) when both C1 and C2 are turning in the same direction Unison motion phase (from C1° = 65 to 90°)

Patient Exclusion Criteria The postinfectious cases associated with otological or pharyngeal infections Torticollis patients with congenital bony anomalies of the occipital-atlas-axis complex. Within the posttraumatic group, cases with concomitant atlanto-occipital and other cervical fracture dislocations and spinal cord injury without radiographic abnormality.

Clinical information

Image technique All angle measurements :axial CT scans using bone algorithms the lower half of the clivus to the base of the C3 body, 3 mm thick without overlap at a 0-degree gantry angle (120kV, 70 mA, with a 2-second scan time) Mild sedation

Angle measurements

Normal template

Group 1 patients

Type I AARF

Type I AARF (Patient 4, Group 1)

Motion Curve of all Group 1 Patients

Group 2 patients

Type II AARF (Patient 5, Group 2)

Type II AARF

Motion Curve of all seven Group 2 Patients

Group 3 patients

Type III AARF (Patient 8, Group 3)

Type III AARF

Motion Curve of all nine Group 3 Patients

Group 4 patients

Motion Curve of all 14 Group 4 Patients

Group 5 patients

Motion Curve of all five Group 5 Patients

Rough diagnostic domains of the three type of AARF

Case 1

Case 2

Summary

Diagnostic paradigm of AARF

Discussion The more horizontal the curve, the more locked are the two bones Diagnostic curve.

Management algorithm of AARF