Quantification of C2 cervical spine rotatory fixation by X-ray, MRI and CT

Abstract

Atlanto-axial rotatory displacement is known to be a cause of childhood torticollis and may as well be responsible for chronic neck pain after rear-end automobile collisions. The objective was to determine whether quantification of C2 malrotation is possible by plain radiographs in comparison to CT as the golden standard. MR imaging was evaluated as to whether it was of equal value in the detection of bony landmarks. C2 vertebra of five human cadaveric cervical spine specimens, ligamentously intact, were rotated using a Steinmann pin in steps of 5 degrees up to 15 degrees right and 15 degrees left. Plain radiographs, CT and MRI images were taken in each rotational step. Data were analyzed for quantification of C2 rotation by three independent examiners. A rotation of 5 degrees led to a spinous process deviation (SPD) from the midline of 3 mm as measured on an a.p. plain radiograph. A coefficient of rotation was calculated (1.62 degrees mm(-1)). Data analyzed by three examiners revealed a small coefficient of variation (0.03). MRI and CT measurements showed comparable results for the quantification of rotation; however, in both techniques the 15 degrees rotation was underestimated. Quantification of upper cervical spine malrotation was possible on plain radiographs using the SPD and a rotation coefficient. MRI and CT were equally successful in the assessment of C2 malrotation.

Rotation of the second cervical vertebra in pediatric patient

“…(1-5) This prevalence occurs because of specific anatomic characteristics of childhood, such as disproportion between head-neck, underdeveloped cervical musculature, laxity of the joint capsule, ligament elasticity and horizontal shape of the articular facets between atlas and axis vertebrae. (3-7) This condition can occur due to inflammation/infection (2,6,7) or trauma, (1,2,4,6) or because of neurogenic or idiopathic origin. (2) …”

“…(7,8) Among imaging exams of bone tissue, radiographies in anteroposterior and lateral projections are of limited use because they do not enable a precise visualization of this alteration, due to difficulties in positioning patients (head offset or source of X-rays, and overlap of structures), leading to radiographic interpretation challenges. (1,6,7) Computed tomography is considered the gold standard procedure. (1,6,7) Images of tridimensional reconstruction provides a global visualization of rotation, therefore helping to establish the diagnosis.…”

“…(1,6,7) Computed tomography is considered the gold standard procedure. (1,6,7) Images of tridimensional reconstruction provides a global visualization of rotation, therefore helping to establish the diagnosis. (2,3,7) In addition, the magnetic resonance image can also be requested to evaluate the risk of vascular-nervous bundle compromising and injuries of the ligaments adjacent to vertebrae.…”

“…(2,3,7) In addition, the magnetic resonance image can also be requested to evaluate the risk of vascular-nervous bundle compromising and injuries of the ligaments adjacent to vertebrae. (1,5-7) …”

“…Treatment can be conservative using immobilization, (3-5,7,9) traction or manual reduction, (3,4,7,9) with the use of analgesic, (3) physiotherapy (1,9) or surgery. (3,7,9) …”