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 evaluate the operative strategy and therapeutic outcomes of the atlantoaxial instability.

METHODSClinical data of 29 patients with atlantoaxial instability were retrospectively analyzed. There were 27 males and 2 females. The mean age was 33 years old with a range from 18 to 54 years. There were fracture of anterior arch of atlas accompanied with ligamentum transversum rupture in 5 cases, odontiod fracture in 7 cases, Hangman fracture in 6 cases, dysplasia of atlas and axis in 10 cases, ankylosing spondylitis in 1 case. The clinical and imaging manifestation of atlantoaxial instability were found in all patients. The symptoms and physical signs of superior cervical spinal cord disease or cervical spinal injury were found in 18 cases. The patients were treated with simple modified Magerl method (7 cases), cannutated screw fixation(6 cases), resection of C2,3 disc throuth the anterior approach and fusion with Zephir titanium plate (4 cases), percutaneous pedicle screw fixation of C2 (2 cases), release and reduction through anterior oropharynx (LRAO) combined with modified Magerl method (4 cases), LRAO and atlas lateral mass screw and plate fixation through posterior approach (3 cases), cervical occipital fusion through C2 pedicle (3 cases).

RESULTSAll patients were followed up with an average time of 17.2 months ranging from 11 to 38 months. All patients obtained anatomical reduction and bone healing. Using Odom standard to evaluation for 18 cases with spinal injury before operation, the results were excellent in 9 cases,good in 7,fair in 2. No injury of vertebral artery, nerve root, spinal cord, infection of incisional wound, breaking or loosening of internal fixatir were found in the study.

CONCLUSIONIdentifying the causes of atlantoaxial instability, rational plan of operation can get satisfactory clinical results.

Adolescent ; Adult ; Atlanto-Axial Joint ; diagnostic imaging ; surgery ; Female ; Humans ; Joint Instability ; diagnostic imaging ; surgery ; Male ; Middle Aged ; Radiography ; Retrospective Studies

OBJECTIVETo evaluate and compare the diagnostic value in atlantoaxial subluxation by CT three-dimensional (3D) reconstruction.

METHODS3D reconstruction findings of 41 patients with atlantoaxial subluxation were retrospectively analyzed, and comparisons were made among images of transverse section, multiplanar reformorting (MPR), surface shade display (SSD), maximum intensity project (MIP), and volume rendering (VR).

RESULTSOf 41 patients with atlantoaxial subluxation, 31 belonged to rotary dislocation, 5 antedislocation, and 5 hind dislocation. All the cases showed the dislocated joint panel of atlantoaxial articulation. Fifteen cases showed deviation of the odontoid process and 8 cases widened distance between the dens and anterior arch of the atlas. The dislocated joint panel of atlantoaxial articulation was more clearly seen with SSD-3D imaging than any other methods.

CONCLUSIONSAtlantoaxial subluxation can well be diagnosed by CT 3D reconstruction, in which SSD-3D imaging is optimal.

Adolescent ; Adult ; Aged ; Atlanto-Axial Joint ; injuries ; Child ; Female ; Humans ; Imaging, Three-Dimensional ; Joint Dislocations ; diagnostic imaging ; Male ; Middle Aged ; Retrospective Studies ; Tomography, X-Ray Computed ; methods

This study aims to assess the effectiveness and advantages of Vertex multiaxial screw system in use for stabilizing the atlanto-axial junction. The entry point of the atlas was located 18-20 mm lateral to the midline and 2.0 mm superior to the inferior border of posterior arch, and the direction of screw was chosen to be about 10 degrees medial to the sagittal plane and about 5 degrees cephalad to the transverse plane. In odontoid vertebra (C2), the direction of the drill bit was guided directly by the medial and superior aspect of the individual C2 pedicle. All screws were placed properly without incidence of nerve or blood vessel injury, and no complication appeared in operation and after surgery. All cases were followed up for an average of 9 months, all cases achieved well reposition and fixation of atlantoaxial joint, average JOA grade was 9.6 before preoperation and 15.9 after operation. Fixation of the atlantoaxial complex using Vertex multiaxial screw system seemed to be a reliable technique and should be considered a good alternative in atlantoaxial fusion. The technique could be used in young patiens.
Adolescent ; Adult ; Atlanto-Axial Joint ; diagnostic imaging ; surgery ; Bone Screws ; Child ; Female ; Follow-Up Studies ; Humans ; Joint Instability ; surgery ; Male ; Middle Aged ; Radiography ; Spinal Fusion ; instrumentation

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

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

OBJECTIVECreating the method of transcutaneous anterior lateral mass fixation for instability of C(1,2).

METHODSThe regular and safe angle and the distance between the median margin of vertebral artery and median line of superior and inferior margin of axis were measured with computerized tomography. Fifteen cases of C(1,2) instability including 7 cases atlanto-axial dislocation, 3 cases of Jefferson's fracture, 1 case of dental fracture and dislocation and 4 cases of fractures of anterior arch of C1 were treated with pertacuneous anterior lateral mass screws and bone grafting with new-designed hole instrumentations according to the measurement of 40 normal atlanto-axial vertebrae.

RESULTSIn posterior-anterior ray the regular angle was 24.0 degrees +/- 3.7 degrees (right side), and 23.8 degrees +/- 1.8 degrees (left side); safe angle is 15.2 degrees - 30.3 degrees (left side) and 14.8 degrees - 32.1 degrees (right side), respectively. The distance between the median margin of vertebral artery and median line of superior and inferior margin of vertebral artery and median line of superior and inferior margin of lateral mass was (5.6 +/- 2.2) mm (right) and (5.8 +/- 1.9) mm (left). In lateral ray the regular angle was 24.1 degrees +/- 1.8 degrees, and safe angle 12.6 degrees - 26.8 degrees. All cases reach a satisfactory result of fixation without the injury of vertebral artery, spinal cord and esophagus. The acupuncture point recovers without infection.

CONCLUSIONSThis operation procedure for instability of C(1,2) has the advantage of less trauma and bleeding, simply operation and bone grafting at the same time. The operation procedure is safe with reasonable instrument and selecting the correct puncture point, angle and depth.

Adult ; Aged ; Atlanto-Axial Joint ; diagnostic imaging ; surgery ; Bone Screws ; Bone Transplantation ; Cervical Vertebrae ; injuries ; Female ; Humans ; Joint Instability ; diagnostic imaging ; etiology ; surgery ; Male ; Middle Aged ; Radiography ; Spinal Fusion ; methods ; Spinal Injuries ; complications

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

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