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At least 361 records · Page 20Linked to original sources
PubMed2002

Rotation of the atlantico-axial joint, investigated using CT and MRI.

The vertebral column is composed of a series of joints, each capable of a specific range of movement. To investigate these movements, a study into the physiological range of rotation at the atlanto-axial joint has been undertaken. The movements and their interpretation under imaging conditions are crucial if any underlying spinal deformity or the consequences of trauma are present in an individual. 28 healthy volunteers were examined using dynamic Magnetic Resonance Imaging with maximum head rotation to the right and left sides in turn. An anatomical specimen of the atlanto-occipital joint was imaged using Computed Tomography with the specimen fixed in varying degrees of rotation. The results indicate that there is a significant but incomplete loss of contact between the articular surfaces of C1 (atlas) and C2 (axis). The range of motion to the right was between 20 and 48.5 degrees (mean 32.4 degrees) and to the left was between 13 and 52.75 degrees (mean 3.2 degrees). Statistical significance between left and right movement was not demonstrated. The instantaneous axis of rotation was examined for the joint and was found to be located within the odontoid peg (dens). These findings indicated that a wide range of movement occurs within the atlanto-axial joint in normal subjects. Furthermore, the appearances under imaging could be misinterpreted as a pathological subluxation. This has implications if the subject with a spinal deformity also has a dysplasia associated with a potential subluxation. The siting of the instantaneous axis of rotation within the odontoid is also important in furthering the understanding of the movement of this joint.

Adolescent↗
PubMed1991

[A case of C2 neurinoma suffering syncopal episodes].

A 32-year-old male had a 4-year history of episodes of loss of consciousness. These episodes occurred several seconds after he would turn his head 60 degrees to the left, and had increased in frequency at the time previous to the operation he underwent. MRI revealed a round mass on the right side between the atlas and the axis. Cerebral angiography demonstrated that the right vertebral artery (VA) was occluded at the transverse foramen of the axis with the head rotated toward the left. The left VA was hypoplastic and no posterior communicating artery was visualized. A lateral surgical approach was performed between the left sternocleidomastoid muscle and the internal jugular vein. A yellowish and elastic but hard tumor was found to compress the VA. Postoperative MRI and vertebral angiography revealed neither residual tumor nor stenosis. Although the VA is frequently compressed by cervical tumors, only a few cases have been reported with tumors whose initial symptom was vertebro-basilar insufficiency. On the other hand, symptomatic stenotic change in the VA due to head movement can occur at the atlanto-axial joint and is named "bow hunter's stroke". In this case, flow of the VA was measured with an ultrasonic flowmeter after the tumor was removed. As the flow proved to change little during head rotation, additional decompression procedures such as removal of the transverse processes were judged unnecessary. Intraoperative arterial flow measurement has been found to be quite useful for evaluating the actual effect of surgical procedures.

Adult↗
PubMed1989

Vertical settling in rheumatoid arthritis. Diagnostic value of the Ranawat and Redlund-Johnell methods.

The usefulness of the recently developed Ranawat and Redlund-Johnell craniometric methods was compared with that of the conventional McGregor method for diagnosing vertical settling (VS) of the skull and the atlas on the axis in 209 patients with rheumatoid arthritis (RA). Statistical analysis of the values obtained from roentgenograms revealed close correlations among the three methods. The first two methods were superior to the McGregor method because the measuring points could be identified on plain roentgenograms of the cervical spine in virtually all cases. The McGregor value could not be determined in 38 (18%) patients. Since medullary compression could be detected by magnetic resonance imaging in all patients who showed abnormal Redlund-Johnell values, the Redlund-Johnell method may be useful for diagnosing advanced VS. It also detects not only atlantoaxial lesions but also atlantooccipital lesions. Thus, the Redlund-Johnell method appears to be the best method for diagnosing VS in RA patients.

Adult↗
PubMed1983

Fusion of the cervical spine for instability.

The orthopedic and neurosurgical literature is neither clear nor consistent in describing an unstable cervical spine. In a series of 25 patients treated by arthrodesis of the cervical spine for instability, 12 had Gallie fusions at the atlantoaxial level. Eight of those fusions were performed for rheumatoid arthritis. In three patients persistent subluxation of the atlas on the axis occurred because the wires were not fully tightened in areas of poor-quality bone. Stable fixation with relief of symptoms was achieved in all patients who had fusions at the subaxial level. Several of these patients had had prolonged nonsurgical treatment. With rheumatoid bone of poor quality, the surgeon must be very careful to tighten the wires only enough to secure a stable reduction for treatment of subaxial cervical instability. Since stability achieved by healing of soft tissue is generally unreliable, prolonged periods of nonsurgical treatment are not justified for traumatic instability.

Arthritis, Rheumatoid↗
PubMed1983

Nonreducible rotational head tilt and atlantoaxial lateral mass collapse. Clinical and roentgenographic features in patients with juvenile rheumatoid arthritis and ankylosing spondylitis.

Nonreducible rotational head tilt resulting from predominantly unilateral collapse of the lateral mass of the atlas (C1) and/or axis (C2) has been characterized in patients with rheumatoid arthritis. An identical phenomenon is reported in five patients with juvenile rheumatoid arthritis (JRA) and in six with ankylosing spondylitis (AS). Most patients had neck pain and crepitus, all had a fixed head tilt deformity, and most also had a rotational deformity. Roentgenographically, all had predominantly unilateral collapse of the lateral masses of C1 and/or C2, and the head always tilted toward the most collapsed side. The patients with JRA had polyarticular disease of long duration and generally mild neck symptoms, with only one requiring neck surgery for pain. The patients with AS tended to have proximal peripheral joint involvement and long-standing disease with more severe neck symptoms; four underwent posterior cervical fusion for intractable pain. None of the 11 patients had demonstrable neurologic deficits.

Adolescent↗
PubMed1979

Surgical decompression for traumatic atlantoaxial subluxation in a weanling filly.

A filly with ataxia and splinting and crepitation in the neck was found to have atlantoaxial subluxation. Radiographic diagnosis was based on the same criteria as those used in other species, ie, increased distance between the atlas and spine of the axis and increased distance between the dens and floor of the atlas. Extensive hemilaminectomy was performed to decompress the spinal cord. Stabilization was not attempted. Immediate postoperative response was encouraging, but the untimely death of the filly prevented further evaluation of the procedure.

Animals↗
PubMed1987

Creation of a three-dimensional atlas by interpolation from Schaltenbrand-Bailey's atlas.

A 0.5-mm step atlas was interpolated from Schaltenbrand-Bailey's atlas. By serial display of the atlas with the desired rotation on a three-dimensional axis, a three-dimensional atlas was created. The newly created atlas can be used for computer-processed stereotactic data display. Any three-dimensionally located point can be displayed within 0.25 mm distance from the point, and spatial understanding of anatomical structures and stereotactic data is facilitated by the three-dimensional display.

Brain↗
PubMed2006

[Injuries to the craniocervical junction].

Injuries to the upper cervical spine (C0-C2) play a major role in surgical treatment of traumatic sequelae in the entire cervical spine. Even though the number of such operations has increased in recent years, there are no clear treatment recommendations for most types of cervical spine injuries. In view of the wide range of injury types and the correspondingly large number of treatment options, this review focuses mainly on the following types of injuries: C0 fractures, occipital condyle fractures (OCF), atlanto-occipital dislocation (AOD), atlas fractures, atlantoaxial dislocation (AAD), and axis fractures. Important aspects of the mechanisms of injury, clinical signs and symptoms, diagnostic procedures, and treatment options are discussed. Special emphasis is placed on comparatively reviewing the different treatment options discussed in the literature. A summary in table form is presented at the end of each chapter for quick reference.

Adolescent↗