OBJECTIVE: To investigate the correlation between the changes of cervical curvature and atlantoaxial instability. METHODS: The correlation between the changes of cervical curvature and atlantoaxial instability was retrospectively studied in 50 outpatients with abnormal cervical curvature (abnormal cervical curvature group) from January 2018 to December 2019. There were 24 males and 26 females in abnormal cervical curvature group, aged from 18 to 42 years old with an average of(30.62±5.83) years. And 53 patients with normal cervical curvature (normal cervical curvature group) during the same period were matched, including 23 males and 30 females, aged from 21 to 44 years with an average of(31.98±6.11) years. Cervical spine X-ray films of 103 patients were taken in lateral position and open mouth position. Cervical curvature and variance of bilateral lateral atlanto-dental space(VBLADS) were measured and recorded, Pearson correlation coefficient analysis was used to study the correlation between the changes of cervical curvature and atlantoaxial instability. RESULTS: Atlantoaxial joint instability accounted for 39.6%(21/53) in normal cervical curvature group and 84.0%(42/50) in abnormal cervical curvature group. There was significant difference between two groups(P<0.01). VBLADS in abnormal cervical curvature group was (1.79±1.01) mm, which was significantly higher than that in normal cervical curvature group(0.55±0.75) mm(P<0.01). Pearson correlation coefficient analysis showed that the size of cervical curvature was negatively correlated with VBLADS. CONCLUSION Cervical curvature straightening and inverse arch are the cause of atlantoaxial instability, the smaller the cervical curvature, the more serious the atlantoaxial instability.
Adolescent ; Adult ; Atlanto-Axial Joint/diagnostic imaging* ; Cervical Vertebrae/diagnostic imaging* ; Female ; Humans ; Joint Instability/diagnostic imaging* ; Kyphosis ; Male ; Radiography ; Retrospective Studies ; Young Adult

OBJECTIVETo provide quantitative foundation for the diagnosis of atlanto-axial rotatory subluxation by analyzing the various imaging features of normal atlanto-axial joints in neutral position and rotary functional position on the MSCT images.

METHODSForty-one normal volunteers were examined by CT on the atlanto-axial joint in neutral position and rotary functional position. By the observation and measurement of atlanto-dental interval (ADI), lateral atlanta-dental space (LADS), VBLADS and rotating angle of atlas on dentate (RAAD), the imaging manifestations and anatomical characteristics were analyzed and compared. In order to compare VBLADS and RAAD and make a correlation analysis between different age groups, 51 normal volunteers were divided into two groups: age younger than 45 years old group and age older than or equal to 45 years old group.

RESULTSThe dens in neutral position deviated in an angle range of (3.22±0.89)°. The articular facets of lateral atlantoaxial joint in rotary functional position had rotatory displacement and the range of the relative rotation angle was (33.85± 2.79)°. Through the correlation analysis of matching data, it could be concluded that there was no correlation between atlantoaxial relative rotation angle and VBLADS within a certain range. There were statistically differences of atlantoaxial relative rotation angle in rotary functional position between two groups.

CONCLUSIONMSCT imaging in rotary functional position can clearly show the anatomical structure and rotation function of a normal atlanto-axial joint, so as to provide a theoretical basis for the diagnosis of atlanto axial rotatory subluxation.

Adult ; Aged ; Atlanto-Axial Joint ; diagnostic imaging ; Female ; Humans ; Male ; Middle Aged ; Multidetector Computed Tomography ; methods ; Rotation

OBJECTIVETo discuss the therapeutic effects of the atlantoaxial pedicle screw system fixation in treatment of atlantoaxial instability.

METHODSFrom June 2003 to March 2010, 32 patients with atlantoaxial instability were treated by atlantoaxial pedicle screw system fixation, included 21 males and 11 females wiht an average age of 42.5 years old ranging from 28 to 66 years. Among them, 18 cases were odontoid process fractures, 7 were congenital dissociate odontoid process, 4 were Jefferson fracture combined with odontoid fracture, 3 were rheumatic arthritis causing atlantoaxial instability. All patients suffered from the atlantoaxial subluxation and atlantoaxial instability. The JOA score ranged from 4 to 14 (means 9.1 +/- 0.3) before operation. The patients had some image examination including the X-ray of cervical vertebrae (include of dynamic position film), spiral CT 3D reconstruction and/or MRI. The position of pedicle screw system implantation,the angle of pedicle screw system implantation and screw length were measured. Operating skull traction. Operation undewent general anesthesia, implanted the pedicle screw, reduction and bone fusion under direct vision. The bone was fixated between posterior arch of atlas and lamina of axis by the lateral combination bended to posterior.

RESULTSOne hundred and twenty-eight atlantoaxial pedicle screws were implanted in 32 patients. No patient had the injure of spinal cord, nerve root and vertebral artery. All patients were followed-up from 6 to 48 months (averaged 16 months). After operation, the JOA score ranged from 11 to 17 (averaged 15.9 +/- 0.2), improvement rate was 86.1%. The fracture of odontoid process were healing completely. All fusion bone were combinated. The internal fixation wasn't loosening and breaking.

CONCLUSIONThe atlantoaxial pedicle screw system fixation was effective method to treat atlantoaxial instability. The method had many advantages, such as provide rigid and short segment fixation, safe and simple, high fusion rate. The method was worth in clinical application.

Adult ; Aged ; Atlanto-Axial Joint ; diagnostic imaging ; injuries ; surgery ; Biomechanical Phenomena ; Bone Screws ; Female ; Humans ; Joint Instability ; surgery ; Male ; Middle Aged ; Tomography, X-Ray Computed

OBJECTIVETo explore the clinical outcomes of atlanto-axial screw-plate fixation and bone fusion for the treatment of atlanto-axial instability.

METHODSFrom June 2003 to June 2008,15 cases with atlanto-axial instability were treated with atlanto-axial lateral mass screw-plate fixation and self-cancellous bone graft fusion. There were 10 males and 5 females with the mean age of 41.7 years (range, from 19 to 72 years). Six cases were old odontoid fracture, 3 cases rheumatoid arthritis, 6 cases odontoid developmental deformity. All patients had symptoms and signs of upper cervical myelopathy and the imaging displayed atlanto-axial instability. JOA scores before operation were from 6 to 11 with an average of 7.4.

RESULTSAll patients were followed up with the mean of 28 months (range, from 9 to 40 months). The follow-up data indicated solid fusion in all patients, posterior reductions were satisfactory, no loosening or screw-plate broken was found. There were 10 cases which spinal cord function improved obviously, 4 cases improved slightly, 1 case no changed in the study. The postoperative JOA scores were from 13 to 17 with an average of 15.6.

CONCLUSIONAtlanto-axial screw-plate fixation and self-cancellous bone graft can stabilize atlas and axis, and promote fusion of atlanto-axial joint, which is an effective method for the treatment of atlanto-axial instability.

Adult ; Aged ; Atlanto-Axial Joint ; diagnostic imaging ; pathology ; physiopathology ; surgery ; Bone Screws ; Female ; Follow-Up Studies ; Fracture Fixation, Internal ; methods ; Humans ; Joint Diseases ; diagnostic imaging ; physiopathology ; surgery ; therapy ; Male ; Middle Aged ; Recovery of Function ; Spinal Fusion ; methods ; Tomography, X-Ray Computed ; Treatment Outcome

Adult ; Atlanto-Axial Joint ; surgery ; Bone Screws ; Female ; Fractures, Bone ; diagnostic imaging ; pathology ; physiopathology ; surgery ; Humans ; Male ; Middle Aged ; Odontoid Process ; injuries ; Tomography, X-Ray Computed

OBJECTIVETo evaluate the therapeutic effects of fixation and fusion with lateral mass screws of the atlas and vertebra dentata pedicle screws for the treatment of upper vertebral instability.

METHODSTen patients with atlantoaxial instability, including 3 with old odontoid fracture and 7 with fresh odontoid fracture (Aderson II) received surgeries for fixation and fusion with lateral mass screws of the atlas and vertebra dentata pedicle screws.

RESULTSNo spinal cord or vertebral artery injuries occurred in these patients after the surgery. The follow-up duration ranged from 3 to 15 months with an average of 8 months. The postoperative JOA scores were from l3.2 to l6.8, with an average of l4.8. Clinical improvement was achieved in 87.5% of the patients, and the implanted bones all fused successfully without internal fixation rupture or mobilization.

CONCLUSIONLateral mass screws of the atlas combined with vertebra dentata pedicle screws allows three-dimensional fixation for treatment of atlantoaxial instability.

Adult ; Atlanto-Axial Joint ; diagnostic imaging ; surgery ; Axis, Cervical Vertebra ; injuries ; surgery ; Bone Screws ; Cervical Atlas ; injuries ; surgery ; Female ; Fracture Fixation, Internal ; methods ; Humans ; Joint Instability ; etiology ; surgery ; Male ; Middle Aged ; Radiography ; Spinal Fractures ; complications ; diagnostic imaging ; surgery ; Spinal Fusion ; methods

OBJECTIVE: To evaluate diagnostic value of spiral CT reconstruction in atlantoaxial injuries. METHODS: The images of 25 cases of spiral CT reconstruction were analyzed and compared with images of CT scan and X-ray. RESULTS: In 7 cases of odontoid process fracture, X-ray demonstrated 4 cases and CT demonstrated 5 cases, whereas the spiral CT reconstruction diagnosed 7 cases, which could display the displacement of fracture clearly. The X-ray and CT showed asymmetric space between left and right gaps of atlantoaxial joint in 6 cases, while spiral CT reconstruction showed normal and excluded the possibility of atlantoaxial dislocation. There was one case of lateral atlantoaxial joint dislocation, which was demonstrated by the spiral CT reconstruction clearly but not by the X-ray and CT scan. There were 3 cases of atlantoaxial congenital deformity (1 case of absence of both posterior arch of atlas and odontoid process and 2 cases of maldevelopment of the odontoid process), which were displayed clearly by spiral CT reconstruction, but misdiagnosed as odontoid process fracture and atlantoaxial subluxation by X-ray and CT scan. CONCLUSION Spiral CT reconstruction can provide the most accurate and integrity imaging information and is very useful in the diagnosis of atlantoaxial injuries and deformity.
Accidents, Traffic ; Adolescent ; Adult ; Atlanto-Axial Joint/injuries* ; Cervical Atlas/injuries* ; Child ; Female ; Forensic Medicine/methods* ; Humans ; Joint Dislocations/diagnostic imaging* ; Male ; Middle Aged ; Odontoid Process/injuries* ; Retrospective Studies ; Spinal Injuries/diagnostic imaging* ; Tomography, Spiral Computed/methods* ; Young Adult

OBJECTIVETo investigate the clinical effect of atlantoaxial pedicle screw internal fixation for treatment of atlantoaxial dislocation.

METHODSSixteen patients with atlantoaxial dislocation were treated from Dec. 2005 to June 2007, included 10 males and 6 females, aged from 38 to 45 years old (means 40.5 years). Among them 12 patients combined with nerve injury, according to ASIA grade: there were 3 cases in grade B, 5 cases in grade C, 4 cases in grade D. All patients received preoperative CT, radiograph and skull traction. Intraoperative posterior approach general spine pedicle screw-rod orthopaedics fixation system used and iliac bone block were implanted in space of posterior atlantal arch and axial vertebral plate. The outcome and complications were observed in the near future.

RESULTSThere was no vascular or neural injury found. The patients were followed up for 12 to 24 months (means 18 months). All head pain, acid storm symptoms were improved after operation. According to the Odom's clinical efficacy evaluation standard, 12 cases were excellent, 4 were good. Eleven cases of 12 with nerve injury recovered significantly. By ASIA classification: 1 cases was in grade B, 2 cases were in grade C, 5 cases were in grade D, 4 cases were in grade E. No looseness or breakage of screw occurred. Bony fusion was achieved in all cases.

CONCLUSIONPosterior approach atlantoaxial pedicle screw internal fixation have the advantages of direct screw placement, short-segment fusion, intraoperative reduction, fixation reliable, high fusion rate, and it can restablish the upper cervical vertebrae stability and help to recover the spinal cord and nerve function.

Adult ; Atlanto-Axial Joint ; diagnostic imaging ; injuries ; physiopathology ; surgery ; Bone Screws ; Female ; Fracture Fixation, Internal ; instrumentation ; Humans ; Joint Dislocations ; diagnostic imaging ; physiopathology ; surgery ; therapy ; Male ; Middle Aged ; Tomography, X-Ray Computed ; Treatment Outcome

BACKGROUNDThe vertebral artery (VA) and atlantoaxial joint (AAJ), with complicated structures, are located in the depths of the head-neck boundary area, the regional anatomy of which cannot be shown globally and directly. This study aims to evaluate three-dimensional CT angiography (3DCTA) in displaying the AAJ, atlantoaxial segment of the vertebral artery (ASVA) and the identification of their interrelations.

METHODSSixty-eight subjects without pathology of the ASVA and AAJ were selected from head-neck CTA examination. All the 3D images were formed with volume rendering (VR) together with techniques of separating, fusing, opacifying and false-coloring (SFOF). On the 3D images, the ASVA and AAJ were observed, and their interrelations were measured.

RESULTSAll the 3DCTA images were of high quality and up to our requirements. They could clearly and directly show the ASVA, ascending along the AAJ. There were 5 curves in the course of the ASVA, of which 2 curves were away from the atlantoaxial joint, one in the 2nd curve of 0.0 mm - 5.4 mm, the other in the 4th of 2.6 mm - 9.2 mm. There was no significant difference in the measurements between left and right (P > 0.05). The curved parts of the ASVA slightly expanded, with the biggest diameter of 5.6 mm in the 4th curve. Statistical comparison shows that the left ASVA is larger than the right (P < 0.05). Variations of the ASVA were found in 8 cases and of the AAJ in 12.

CONCLUSIONS3DCTA can globally and directly demonstrate the structures of the AAJ, ASVA and their interrelations. The 3D imaging data make up and enrich the research contents of regional anatomy and lay the foundation for related study and applications.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Atlanto-Axial Joint ; diagnostic imaging ; Female ; Humans ; Imaging, Three-Dimensional ; methods ; Male ; Middle Aged ; Tomography, X-Ray Computed ; methods ; Vertebral Artery ; diagnostic imaging ; Young Adult

OBJECTIVETo evaluate the technique of C1-C2 transarticular screw fixation for atlantoaxial instability or dislocation.

METHODSAmong 14 patients with atlantoaxial instability, 10 were male and 4 patients were female, with an average age of 38.6 years ranging from 17 to 62 years. All patients were treated by internal fixation with transarticular screws.

RESULTSThere were 28 screws applied in 14 patients. All patients were followed up. The average follow-up period was 16 months (range, 9 to 35 months). The postoperative JOA score was ranging from 13.8 to 15.8 with the average score of (14.50 +/- 0.66) and the improved rate of (76.12 +/- 4.94)%. No spinal injury and vertical artery injury was found and osseous fusion was completed in all patients.

CONCLUSIONThe technique of C1-C2 transarticular screw fixation is one of the best treatments for atlantoaxial instability. Without the help of structural bone graft and aided internal fixation, morselized cancellous bone graft can acquire effective osseous fusion.

Adolescent ; Adult ; Atlanto-Axial Joint ; pathology ; surgery ; Bone Screws ; Female ; Follow-Up Studies ; Humans ; Internal Fixators ; Joint Instability ; diagnostic imaging ; physiopathology ; surgery ; therapy ; Male ; Middle Aged ; Radiography ; Tomography Scanners, X-Ray Computed ; Treatment Outcome ; Young Adult