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At least 73 records · Page 4Linked to original sources
PubMed1991

Imaging of the atlas (C1) and axis (C2).

In imaging the atlantoaxial region in injured patients, the initial modality is plain radiography. The lateral C-spine as well as the open-mouth view are essential in this regard. On these views, it is not only important to examine the bony contour but also to look for indirect signs of injury such as prevertebral soft-tissue swelling, air in the prevertebral space, an increased width of the anterior atlantodental interval, and overriding of the C1-C2 joint on one side (the so-called wink sign of atlantoaxial rotatory subluxation). In patients in whom there is a high index of suspicion for occult trauma, but without fractures suggested or adequately visualized on routine films, or in those with severe cranial trauma, further studies should be pursued. CT scan is the modality of choice in optimally imaging the bony contours of the axis and atlas. It has limitations in visualizing transversely oriented fractures such as high dens fractures, transverse fractures of the facet joints (although widening of the facet joint is an indirect indication of facet fracture), or transverse arch fractures. Plain tomography may better demonstrate such transverse fractures but has several disadvantages. Plain tomography is often not as readily available as CT; it requires that the patient be placed in lateral decubitus position to obtain lateral tomograms, which may be contraindicated in such clinical circumstances; and it is not as easy to appreciate three-dimensional relationships on plain tomography as it is on CT. CT clearly defines the location of displaced bone fragments in relationship to the spinal canal as well as often demonstrating disc injuries. Ligamentous injury, though potentially visualized directly on MR imaging, is more commonly addressed with flexion-extension films. Flexion-extension studies should, obviously, be performed only in awake, oriented patients who are without neurologic deficit, and the studies should be done with close physician supervision and stopped at the first onset of pain. MR imaging may be helpful in demonstrating soft-tissue injuries such as hemorrhage, disc herniation, nerve root impingement, and direct spinal cord damage.

Adult↗
PubMed1989

Occipitoatlantoaxial malformation with duplication of the atlas and axis in a half Arabian foal.

An unusual occipitoatlantoaxial malformation is described in a 2-week-old male part Arabian foal that was unable to stand at birth and showed signs of spastic tetraparesis due to a cervical spinal cord compression. There were 2 atlases present. One was fused to the occipital bones. The other articulated with the first atlas and an axis which had a long dens that projected into the vertebral canal. Examination of the ossification centers of the axis indicated partial duplication of that bone.

Abnormalities, Multiple↗
PubMed1999

Unilateral osseous bridging between the arches of atlas and axis after trauma.

STUDY DESIGN: This is a case report. OBJECTIVE: To present a case of osseous bridging between C1 and C2 of posttraumatic origin and with an associated closed head injury and to discuss its pathogenesis and clinical outcome after surgical resection. SUMMARY OF BACKGROUND DATA: Heterotopic ossifications of posttraumatic origin in the spine are rare. To the authors' knowledge, no cases have been reported of spontaneous bony bridging between C1 and C2 with a posttraumatic origin. METHODS: Heterotopic ossifications were detected when pain and limited axial rotation (left/right 10 degrees/0 degree/20 degrees) were persistent, despite intensive physical therapy. Because heterotopic ossifications were ankylosing C1 and C2, the decision was to resect the osseous bridge in combination with a careful mobilization of the cervical spine. Functional computed tomography was performed for analysis of the postoperative results. RESULTS: Four months after surgery, clinical examination showed asymptomatic increased axial rotation. Functional computed tomography indicated that left C1-C2 axial rotation was reduced, possibly related to impingement caused by residual bony spurs. Pathologic changes in the surrounding soft tissue may be another important factor in the persistent limitation of rotation. CONCLUSIONS: Osseous bridging between C1 and C2 may be considered when persistent pain and limited axial rotation are observed after trauma. Operative resection, together with careful intraoperative and postoperative mobilization, may be the treatment of choice.

Abdominal Injuries↗
PubMed1978

Some specific anatomical features of the atlas and axis: dens, epitransverse process and articular facets.

Metrical and morphological findings, based on 107 human vertebral columns, related to the variations of the dens are given, and differences in the depth of the superior articular facets of the atlas and specific pertinent details related to the os odontoideum and epitransverse process are also provided and their possible clinical relevance indicated. Findings reveal considerable variation in the height of the dens (11 to 18 mm), but remarkably little in its anteroposterior and transverse diameters at the root. The use of the term "hypoplasia" with reference to the dens is discussed, and a need for more rigid criterian in the use of this term stressed. It is also suggested that there may be sufficient radiological evidence in a lateral radiography to lead one to suspect the presence of an os odontoideum or a separate dens caused by trauma in the distant past.

Adult↗
PubMed1987

CT-functional diagnostics of the rotatory instability of upper cervical spine. 1. An experimental study on cadavers.

Twelve specimens of the upper cervical spine were functionally examined by using radiography, cineradiography and computerized tomographic (CT) scan. The range of rotation was measured from CT images after maximal rotations to both sides. The left alar ligament was then cut and the examination repeated. The alar and transverse ligaments could be differentiated on CT images in axial, sagittal, and coronal views. Rotation at occiput-atlas was 4.35 degrees to the right and 5.9 degrees to the left and at atlas-axis it was 31.4 degrees to the right and 33 degrees to the left. After one-sided lesion of the alar ligament, there was an overall increase of 10.8 degrees or 30% of original rotation to the opposite side, divided about equally between the occiput-atlas and the atlas-axis. It is concluded that a lesion (irreversible overstretching or rupture of alar ligaments) can result in rotatory hypermobility or instability of the upper cervical spine.

Axis, Cervical Vertebra↗
PubMed2006

Acute combination fracture of atlas and axis: "triple" anterior screw fixation in a 92-year-old man: technical note.

BACKGROUND: The combination of odontoid and bilateral transarticular C1-C2 anterior screw fixation is a recent addition in treating C1-type II odontoid fractures. When feasible, it ensures early maximal stability, even if it slightly reduces the mobility of C1-C2 complex. We report a case of combination atlas-type II odontoid fracture that occurred in a 92-year-old man. The instability was treated with odontoid screw fixation and anterior bilateral C1-C2 transarticular screw fixation in a single stage. The aim of the article is to describe the feasibility of "triple" anterior screw fixation in the presence of C1-type II odontoid fracture. METHODS: The diagnosis, treatment, and outcome of a 92-year-old patient with mild tetraparesis caused by C1-type II odontoid fracture were assessed. RESULTS: Cervical x-rays, computed tomographic scan, and magnetic resonance imaging demonstrated a fracture of posterior arch of C1, associated with type II odontoid fracture and with presumable damage of C1 transverse ligament. Magnetic resonance imaging also showed a high cervical centromedullary area slightly hyperintense in T1-weighted images. Treatment consisted of odontoid and bilateral C1-C2 transarticular screw fixation with single anterior approach. The admission neurologic conditions improved and the patient was early mobilized. CONCLUSIONS: The authors suggest that in presence of C1-type II odontoid fracture, the triple anterior screw fixation has to be taken into account as salvage procedure, especially if other methods of stabilization failed or cannot be safely performed. This technique seems to be safety feasible also in old patients, as our report and the experience of others confirm.

Acute Disease↗