The Os odontoideum is a developmental anomaly of the axis in which the odontoid process is divided transversely. The Atlanto-axial dislocation due to Os odontoideum is presented. At first, we have performed the posterior atlanto-axial fusion with wire fixation. But the posterior fusion failed in realignment and did not adequately decompress the deformed cord by encroachment on its ventral surface. Next time, we have experienced further improvement following transoral decompression and anterior fusion.
Axis, Cervical Vertebra ; Decompression* ; Dislocations* ; Odontoid Process

With changing mechanisms of injury, heightened clinical awareness, and better diagnostic technology, odontoid fractures constitute 9~18% of cervical fractures in recent reports. The odontoid type II fracture is the most common axis fracture and it is also the most difficult to treat. Type II fractures with greater than 6mm dens dislocation have a higher incidence of nonunion with nonoperative therapy and should be offered early operative reduction with fusion. Recently we have experienced a young male patient with odontoid type II fracture. The degree of dens dislocation was 8mm. The fractured odontoid process was removed through transoral-transpharyngeal approach and bone fusion was performed with iliac bone. And the inserted bone was fixed with screws and mini-plate for further stabilization. The operative result was good without any serious complications. The operation technique is detailed.
Axis, Cervical Vertebra ; Dislocations ; Humans ; Incidence ; Male ; Odontoid Process

Fracture of odontoid process is relatively common, but fracture of axis body without fracture of odontoid precess is known to be exceptionally. Recently, we have experienced a case of axis body fracture complicating typical Brown-Sequard syndrome below the level of C4, and we present the case with the review of literature.
Axis, Cervical Vertebra* ; Brown-Sequard Syndrome* ; Odontoid Process

Type II fracture of the odontoid process is the most common form of axis fracture, and because of the difficulty in healing, its results may be fatal. The authors subclassified these fractures as anteriorly displaced(type II-A), posteriorly displaced(type II-P), and non displaced(type II-N). Twelve patients with type II fractures underwent anterior screw fixation : three were type II-A : one, type II-P : and eight, type II-N. The mean duration of follow-up was 29.3 months, and all patients except two showed good alignment and stable fixation : these exceptions were type II-A, with 9mm displacement, and showed delayed failure of screw fixation. All type II-N, II-P, and II-A, with 3mm displacement, were successfully treated. We conclude that selection of the treatment modality should be based on the direction of displacement of odontoid process. For type II-N, II-P and II-A fractures, where displacement is mild, anterior screw fixation is a reliable method, but for type II-A fracture, with severe displacement, posterior fixation should be considered.
Axis, Cervical Vertebra ; Follow-Up Studies* ; Humans ; Odontoid Process*

Fibrous dysplasia is a benign disorder of bone primarily affecting young people from childhood through the third decade. It usually manifests as an enlargement of bones in and about the orbits or the the cranial vault. Whether localized or diffuse, it rarely involves the cervical spine. We report a case of fibrous dysplasia involving axis combined with atlantoaxial instability which was caused by odontoid process fracture. Transfacetal screw fixation augmented with Halifax interlaminar clamp technique was applied to obtain atlantoaxial stability. Postoperative course was unevenful and postoperative radiologic findings revealed favorable fixation of atlantoaxial joint. The pertinent literature on fibrous dysplasia and atlantoaxial instability is reviewed and discussed.
Atlanto-Axial Joint ; Axis, Cervical Vertebra ; Odontoid Process ; Orbit ; Spine*

No abstract available.
Axis, Cervical Vertebra*

PURPOSE: To evaluate the clinical usefulness and its own characteristic of Seohan computerized 85-hue test(SCHT-85) which was developed by authors. METHODS: SCHT-85 was performed in 89 normal subjects and 41 subjects with color defects diagnosed by Hardy-Rand-Rittler test(HRR test) and Farnsworth Munsell 100-hue test(FM 100-hue test) and total error scores(TES) according to the age in normal subjects and TES and central cap in subjects with color defects were determined. RESULTS: In normal subjects, TES of SCHT-85 according to the age were slightly higher than those of FM 100-hue test and highly correlated with those of FM 100-hue test. TES of SCHT-85 were increased according to the degree of abnormality in the HRR test in subjects with color defects. TES of SCHT-85 were lower than those of FM 100-hue test in normal subjects and higher than those of FM 100-hue test in subjects with color defects. In subjects with color defects, the central cap of SCHT-80 showed the tendency to yellowgreen-purple axis in protan and green-bluepurple axis in deutan compared to that of FM 100-hue test. CONCLUSIONS: SCHT-85 is highly correlated with FM 100-hue test and seems to be more useful to differentiate normal subjects and subjects with color defects than FM 100-hue test.
Axis, Cervical Vertebra

No abstract available.
Axis, Cervical Vertebra

No abstract available.
Axis, Cervical Vertebra*

OBJECTIVES: This study compared the mechanical properties of various instruments for canal exploration and glide-path preparations. MATERIALS AND METHODS: The buckling resistance, bending stiffness, ultimate torsional strength, and fracture angle under torsional load were compared for C+ file (CP, Dentsply Maillefer), M access K-file (MA, Dentsply Maillefer), Mani K-file (MN, Mani), and NiTiFlex K-file (NT, Dentsply Maillefer). The files of ISO size #15 and a shaft length of 25 mm were selected. For measuring buckling resistance (n = 10), the files were loaded in the axial direction of the shaft, and the maximum load was measured during the files' deflection. The files (n = 10) were fixed at 3-mm from the tip and then bent 45degrees with respect to their long axis, while the bending force was recorded by a load cell. For measuring the torsional properties, the files (n = 10) were also fixed at 3-mm, and clockwise rotations (2-rpm) were applied to the files in a straight state. The torsional load and the distortion angle were recorded until the files succumbed to the torque. RESULTS: The CP was shown to require the highest load to buckle and bend the files, and the NT showed the least. While MA and MN showed similar buckling resistances, MN showed higher bending stiffness than MA. The NT had the lowest bending stiffness and ultimate torsional strength (p < 0.05). CONCLUSIONS: The tested instruments showed different mechanical properties depending on the evaluated parameters. CP and NT files were revealed to be the stiffest and the most flexible instruments, respectively.
Axis, Cervical Vertebra ; Torque