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At least 145 records · Page 8Linked to original sources
PubMed2005

Atlantoaxial joint distraction for treatment of basilar invagination secondary to rheumatoid arthritis.

We present our experience of treating two cases of rheumatoid arthritis involving the craniovertebral junction and having marked basilar invagination by an alternative treatment method. In both the cases, the facets were osteoporotic and were not suitable for screw implantation. The patients were 66 and 72 years of age and both patients were females. Both the patients presented with complaints of progressively increasing spastic quadriparesis. Surgery involved attempts to reduce the basilar invagination and restore the height of the 'collapsed' lateral mass by manual distraction of the facets of the atlas and axis and forced impaction of titanium spacers in the joint in addition to bone graft harvested from the iliac crest. The procedure also provided stabilization of the region. No other fixation procedure involving wires, screws, plate and rods was carried out simultaneously. Following surgery both the patients showed symptomatic improvement and partial restoration of craniovertebral alignments. Follow-up is of 2 and 24 months. Distraction of the facets of atlas and axis and impaction of metal implant and bone graft in the facet joint can assist in reduction of basilar invagination and fixation of the region in selected cases of rheumatoid arthritis involving the craniovertebral junction.

Aged↗
PubMed1994

Plate and screw fixation for atlanto-axial subluxation.

Our experience with 30 cases of atlanto-axial dislocation, over the period of 3 years and 9 months, is described. A modified plate and screw method of fixation of the lateral masses of the atlas and axis was successfully used in these cases. The technical aspects and merits of the method, wherein a 100% union rate was achieved, with no morbidity, mortality, or instrument fatigue or failure, are presented. The average follow-up period is of 19 months. The technique provided immediate rigid segmental internal fixation, permitting early mobilization with minimal external support. Onlay and interfacetal bone grafts subsequently produced bony fusion. Direct application of screws to the atlas and axis, thus utilizing the firm purchase in their thick and large cortico-cancellous lateral mass, provides a biomechanically strong fixation of the region. Occipito-cervical fusion can be achieved in selected cases by a modification of the method. It appears that such a method of fixation could be useful at least in some complex congenital or traumatic craniovertebral region instability where the conventional methods have failed or are not suitable.

Adolescent↗
PubMed1993

Hoxb-4 (Hox-2.6) mutant mice show homeotic transformation of a cervical vertebra and defects in the closure of the sternal rudiments.

Two Hoxb-4 (Hox-2.6) mutations were introduced into the mouse germline. The overt phenotype caused by one of the mutations was assayed on two different genetic backgrounds, an inbred 129SvEv and a hybrid 129SvEv-C57BL/6J. The allele hoxb-4' is a disruption of the first exon and causes two obvious skeletal changes: a partial homeotic transformation of the second cervical vertebra from axis to atlas and a defective morphogenesis of the sternum. Both phenotypes have incomplete penetrance and variable expressivity when assayed in the hybrid genetic background, but the sternum defect is completely penetrant in the inbred background. The mutant allele hoxb-4s has a premature stop codon, introduced by the "hit and run" method in the second exon, that disrupts the third helix of the homeodomain. This allele also causes the partial homeotic transformation of axis to atlas, but it does not affect the sternum.

Animals↗
PubMed2003

Atlantoaxial interlaminar distances in cervical flexion in children.

OBJECT: To the best of the authors' knowledge, no quantitative analysis of the atlantoaxial interlaminar distance in flexion (ILD) in children exists in the medical literature. In this study they sought to determine the age-matched relationship between the posterior elements of the atlas and axis in children in cervical spine flexion, to be used as an adjunct to the atlantodental interval in common clinical use. METHODS: Lateral radiographs of the cervical spine in full flexion were analyzed in 74 children. The atlantoaxial ILD was defined as the distance between a midpoint of the anterior cortices of the atlantal and axial posterior arches. The mean ILD for the entire group was 19 mm (range 8-30 mm). No significant difference was seen between male and female patients (p = 0.084). When stratified by age, the mean ILD was 12.3 +/- 3 mm (15 cases) in children age 3 years or younger and 20.5 +/- 4.7 mm (59 cases) in children age older than 3 years. Further stratification of the groups yielded a mean ILD of 10.4 +/- 1.4 [eight cases]) in children age 1 to 2 years, and 14.4 +/- 4.7 mm (seven cases) in children age 3 years. In children older than 3 years of age the mean ILD was consistently approximately 20 +/- 5 mm regardless of age. CONCLUSIONS: Rapid, safe, and accurate diagnosis of the cervical spine is essential in critical care. Knowledge of the distance between the posterior elements of the atlas and axis in flexion should enhance the clinicians' (those who clear cervical spines) ability to diagnose accurately atlantoaxial instability on lateral radiographs obtained in flexion.

Adolescent↗
PubMed1982

Nonreducible rotational head tilt and lateral mass collapse. A prospective study of frequency, radiographic findings, and clinical features in patients with rheumatoid arthritis.

Of 126 hospitalized, but otherwise unselected, patients with rheumatoid arthritis, 12 (10%) had a persisting nonreducible rotational head tilt deformity (NRRHT). These 12 were grouped with an additional 12 similar subjects, previously found to have the same condition, and all 24 were compared with the remaining 114 who did not have head tilt. Patients with NRRHT differed significantly from the others in that the former were more likely to have a destructive peripheral arthritis, headache, limited neck motion, and various cervical subluxations. All 24 subjects with NRRHT had predominately unilateral collapse of the lateral masses of the atlas and/or axis, compared with only 2 of the 114 with normal head position. The head always tilted to the side of the lateral mass collapse, which appeared to be the sole or major cause of the abnormal head position.

Aged↗
PubMed1984

[Hangman's fracture in ventrally flexed traction].

Hangman's fracture in ventrally flexed traction between 10(6) and 75 degrees is analyzed on the basis of 220 fracture trials on plaster of real bone preparations of the atlas and axis of two adults. Hangman's fractures, which are usually regarded as a form of injury from dorsal flexion, occurred in 25% of the fracture trials under this kind of strain. Frequency depended on flexion angle, as well as on inclination of the dens axis. Thus Hangman's fractures occurred, as a whole, more frequently in the kyphotic dens type than in the lordotic type and were found as a rule at 75 degrees flexion. Furthermore, the investigations showed that pedicles can by no means be regarded as the sole predilection site for fracture. A detailed description is provided on why the Hangman's fracture type, due to ventrally flexed traction, can be included in the group of bone injuries arising from flexion, with tensile stress of the dorsal parts of the dens and the corpus axis, on the one hand, and the upper side of the axis arch on the other. Hence, the injury picture ranges from the dorsal arch fracture to the horizontal rupture through the superior articular facies and the corpus axis, as documented by substantial evidence.

Adult↗
PubMed1994

Posterior atlantoaxial fusion. A new internal fixation device.

STUDY DESIGN: Biomechanical and clinical testing of an atlantoaxial posterior fixation device. OBJECTIVES: The authors tested an internal fixation device to maintain the atlas and axis in an anatomic relationship while fusion occurs. The device should also facilitate intraoperative reduction of any residual anterior atlantoaxial subluxation. The device should allow the use of cancellous rather than cortical bone graft. SUMMARY OF BACKGROUND DATA: Previous techniques of atlantoaxial fusion were not universally successful, and the quality of reduction was assessed infrequently. METHODS: Biomechanical testing of the fixator and clinical use in two "problem" patients requiring atlantoaxial fusion. RESULTS: Biomechanical testing indicated the device should be successful. Clinical testing was successful. CONCLUSION: The new fixator facilitates posterior atlantoaxial fusion in an anatomical position.

Atlanto-Axial Joint↗
PubMed1998

Spinal canal capacity in simulated displacements of the atlantoaxial segment: a skeletal study.

In normal, physiological circumstances there is ample room in the spinal canal to accommodate the spinal cord. Our study aimed to identify the degree of compromise of the spinal canal which could be anticipated in various atlantoaxial pathological states. We examined paired atlas and axis vertebrae using high-definition radiography and simultaneous photography in both normal and simulated pathological orientations in order to measure the resultant dimension of the spinal canal and its percentage occlusion. At the extreme of physiological axial rotation (47 degrees) the spinal canal is reduced to 61% of its cross-sectional area in neutral rotation. The spinal cord is thus safe from compromise. Atlantoaxial subluxation of up to 9 mm reduces the area of the spinal canal, in neutral rotation, to 60% with no cord compromise. Any rotation is, however, likely to cause cord compression. The mechanism of fixation in atlantoaxial rotatory subluxation could be explained by bony interlocking of the facet joint, reproducible in dry bones.

Atlanto-Axial Joint↗
PubMedDate not supplied

Bony anomalies of the craniocervical junction.

A review of the literature on bony anomalies of the craniovertebral junction was carried out with emphasis on anomalous manifestations associated with the occipital bone, atlas and axis vertebrae. A summary of the evolution and normal development of the above bony structures and the embryological structures contributing to the bony anomalies is presented. In addition the diagnostic measurements used for the diagnosis of the bony anomalies of the craniocervical junction and their clinical presentation were summarised. This review was prepared with the aim of providing reference material for neurosurgeons and radiologists.

Atlanto-Axial Joint↗
PubMed1975

[Transoral approach for the treatment of atlanto-axial dislocation with the Os odontoideum and obstruction of the bilateral vertebral arteries (author's transl)].

The two approaches are well-known in the surgical treatment of atlanto-axial dislocation, the one is the anterior and the other is the posterior approach. The indication of these methods is still controversial. This report concerns with one case of atlanto-axial dislocation with the separate odontoid and bilateral obstruction of both vertebral arteries, which was successfully treated by transoral decompression and fusion between the bodies of the atlas and axis. The reasons why we chose this method were: (1) the spinal cord decompression was necessary because of the presence of compression of the cord by the separate odontoid process, (2) the spinal fusion had to be performed to stabilize the atlanto-axial articulation, (3) it was necessary to avoid the damage of collateral circulations to the brainstem through the deep cervical arteries demonstrated by bilat vertebral angiography. The posterior approach is highly susceptible to injure these collateral circulations.

Adolescent↗