| BackgroundAtlas and axis which anatomic structure is peculiarity and complicate is located in the corresponding position of vital center and is called "upper cervical vertebrae". The disease in upper cervical vertebrae is result in spinal cord compression very easily and the patient present clinical symptoms, even present palsy or threat to life, so it is very difficult to treat it. Atlantoaxial posterior approach is common operation for treat the disease in upper cervical vertebrae, there are Gallie technology, Brooks technology, Halifax clamp technology, Apofix technology, Magerl technology, massa lateralis atlantis screw fixation, atlantoaxial pedicle screw fixation and massa lateralis atlantis screw fixation combined with axial vertebral plate screw fixation, very technology has respectively advantage, disadvantage and biomechanical characteristics. It is one of effective way to treat atlantoaxial unstability by Magerl technology combined with Gallie technology at present. The stability that treated by Massa lateralis atlantis screw fixation is as same as by Magerl technology, but it is difficult to reveal and is easy to injury the spinal cord, nerve root and vertebral artery by massa lateralis atlantis screw fixation. The stability that treated by atlantoaxial pedicle screw fixation is as same as by Magerl technology, and it isn't essential to reveal lateral mass, but it is difficult to reveal and needling mark is not clear by atlantoaxial pedicle screw fixation. Three needling technology which has respective advantage and disadvantage are used for atlantoaxial pedicle screw fixation at present, but they aren't facility and accurate needling technology for atlantoaxial pedicle screw fixation. Ma had found that the stability was sufficient that used atlantoaxial atlantoaxial pedicle screw fixation with unilayer cortical screw. The upper cervical vertebrae is located in deep position, anatomic structure is complicate, variation is obvious and the disease is multiplicity, so it is apparently insufficient that upper cervical vertebrae would be studied only by anatomic study which couldn't individually provided treatment scheme, but the complicate structure of the upper cervical vertebrae can be clearly showed by 3D-CT which could retrieved the shortage by common X-ray, CT, MRI and orthopedic navigation, so 3D-CT could individually provided treatment scheme for treat the disease in the upper cervical vertebrae.Therefore, in this study which contain applied anatomy, section anatomy, biomechanical study and 3D-CT exploratory development, we should observe the morphous of atlantoaxial vertebrae and measured the related parameter of atlantoaxial vertebrae, we should search the bony mark of needling and determine needling way and identify needling depth for atlantoaxial pedicle screw fixation, we should provide the feasible evidence, needling point, needling depth and needling direction for atlantoaxial pedicle screw fixation; we should evaluate and provide diadynamic criteria of congenital atlantoaxial dislocation and basilar invagination and provide assessment evidence of severity of spinal cord or nerve injury; we should evaluate the 3D-CT characteristics of congenital atlantoaxial dislocation and basilar invagination and emphasize that different treatment regimen must be provided individually to different patient.Objectives1. To search the bony mark of needling for atlantoaxial pedicle screw fixation, to produce a facility and precise needling technology for atlantoaxial pedicle screw fixation.2. To observe atlantoaxial os integumentale distribution and to evaluate the limiting factor of atlantoaxial pedicle screw needling technology.3. To evaluate biomechanical characteristics of different needling depth of different atlantoaxial pedicle screw needling technology.4. To evaluate diadynamic criteria of congenital atlantoaxial dislocation and basilar invagination and to provide assessment evidence of severity of spinal cord or nerve injury.5. To evaluate the 3D-CT characteristics of congenital atlantoaxial dislocation and basilar invagination, to emphasize that different treatment regimen must be provided individually to different patient.Materials and methods1. 60 antiseptic atlantoaxial vertebrae were harvested, the morphous and morphologic change of every specimen was observed carefully, the related anatomic parameters were measured by vernier caliper and conimeter.2. 30 antiseptic atlantoaxial vertebrae were harvested and dissected, the morphous and morphologic change of every specimen was observed carefully, the related anatomic parameter were measured by vernier caliper and conimeter.3. 28 antiseptic atlantoaxial vertebrae with 20-40 years old were harvested, the maximum draw power of different depth of different atlantoaxial pedicle screw needling technology with left and right cross combination way were measured by WDW3100 biomechanical tester4. 30 patients that were suffered with inferior cervical fracture but weren't involve to atlantoaxial vertebrae were scanned by SOMATOM Plus 4 model, the altantoaxial vertebral morphous and morphologic change of every patient was observed carefully, the related 3D-CT parameter were measured by SUN magic view 1000.5. The case data and 3D-CT data of 12 patients suffered with congenital atlantoaxial dislocation were harvested, the altantoaxial vertebral morphous and morphologic change of every patient was observed carefully, these related 3D-CT parameters were measured by SUN magic view 1000 and analyzed mutually with the case data.6. The case data and 3D-CT data of 10 patients suffered with basilar invagination were harvested, the altantoaxial vertebral morphous and morphologic change of every patient was observed carefully, these related 3D-CT parameters were measured by SUN magic view 1000 and analyzed mutually with the case data.7. The measured parameters were analyzed by SPSS 13.0, statistical analytical method were contained descriptive statistical analysis, variance analysis of multi-sample mean comparison and q test of two-two comparison, t test of two-sample mean comparison, linerar correlation analysis.Results1. The superior border of posterior arch of atlas was looked as a clivas from norma posterior, about 50% posterior arch of atlas were connected with lateral mass and transverse process near horizontally in the most interior notch of vertebral artery after descended obviously, so called it as "typical posterior arch of atlas" and could be divided to five regions which regions were top region, stable descend region, manifest descend region, near horizontal region and connect region, and a few posterior arch of atlas which morphous was irregularity were connected with lateral mass and transverse process. Most posterior tubercle of atlas were eminence from norma lateralis, anterior border of posterior arch and superior border of pedicle and posterior border of lateral mass were connected to a line, which was looked as "U" shape, so called "U" shape line; anterior border of posterior arch and superior border of pedicle and superior border of transverse process were connected to a line, which was looked as "L" shape, so called "L" shape line, the basal part of both line was pedicle. Therefore, while the posterior arch of atlas is typical, the vertical needling point would be located in the midpoint of posterior arch of altas between obvious descending part and near horizontal part; while the posterior arch of atlas is not typical, the vertical needling point would be located in midpoint of posterior arch of altas (the distance from midpoint of posterior arch of altas to posterior median line is 18mm, it couldn't be less than 14mm inwardly and couldn't be more than 22mm ectadly).The introversion needling point would be located in the midpoint of posterior arch of altas between near horizontal part and connective part.2. The width and height of lateral mass of atlas and the width of the thinnest part of posterior arch of altas were more than the screw diameter (3.5mm) obviously, the height of the thinnest part of posterior arch of altas were more than 4mm mostly, needling depth of this technology was 28mm approximately, the needling direction would be upward about 5°and wouldn't be introversion, the limiting factor was the height of the thinnest part of posterior arch of altas. Introversion needing technology of altas pedicle screw fixation was feasible too, needling depth of this technology was 24mm approximately, the needling direction would be inward about 5°and wouldn't be upward, the limiting factor was exposure latitude, introversion angle and injury to the periphery tissue. 3. The pedicle width and height of axis were more than the screw diameter (3.5mm) obviously, needling depth of this technology was 28mm approximately, needling direction was inward about 15°and upward about 35°.4. The os integumentale was thickness and cancellated bone was thinness even no in pedicle part of atlas. The os integumentale was thickness and cancellated bone was thinness in pedicle part of axis.5. There wasn't statistics difference of the maximum draw power between these three needling technology groups of the same needling depth, The maximum draw power of different needling depth of atlas pedicle screw vertical needling technology were more than the maximum draw power of different needling depth of atlas pedicle screw introversion needling technology, and both maximum draw power were more than the maximum draw power of different needling depth of axis pedicle screw needling technology; The maximum draw power of needling 1/3 of three needling technology was minimum, needling 2/3 was secondary small, needling 3/3 was secondary big, needling 4/3 was maximum, but the atlas or axis was easy to burst apart when it was drown in needling 4/3, there was statistics difference of the maximum draw power between these four needling depths groups of three needling technology.6. The normal ratio of SAC/sagittal diameter was 0.55-0.65, if this angle was less than 0.50, it would be diagnosed as congenital atlantoaxial dislocation or basilar invagination ; if this ratio was less than 0.40, it would be present injury of spinal cord or nerve. The less the ratio of SAC/sagittal diameter was, the more the ratio of ADI/sagittal diameter was, the less the JOA score was, and the more the severity of spinal cord or nerve injury.7. The central altas angle of congenital atlantoaxial dislocation was more than the central axis angle of basilar invagination, and both angle were more than the central axis angle of adult normal, there was statistics difference between the central axis angle of congenital atlantoaxial dislocation and the central axis angle of adult normal. the normal central altas angle was 10°-35°, if the angle was more than 35 , it would be diagnosed as congenital atlantoaxial dislocation; if the angle was more than 40°, it would be present injury of spinal cord or nerve. The more the central altas angle was, the less the ratio of SAC/sagittal diameter was, the more the ratio of ADI/sagittal diameter was, the less the JOA score was, and the more the severity of spinal cord or nerve injury. there was statistics difference between the central axis angle of basilar invagination and the central axis angle of adult normal too, if the angle was more than 30°, basilar invagination maybe be presented, but there was not statistics difference respectively between the central axis angle and the ratio of SAC/sagittal diameter, the ratio of ADI/sagittal diameter, the JOA score of basilar invagination.8. Most sclerotin no fusion area which contained fibrous tissue were found in the junction between odontoid process and axial vertebral body, which long axis was perpendicular to longitudinal axis of odontoid process, a transversal line which was drown follow the long axis of sclerotin no fusion area was located in the junction between odontoid process and axial vertebral body, so called "the interstitial line between odontoid process and atlas"; A few sclerotin complete fusion area were found in the junction between odontoid process and axial vertebral body. The normal ratios of the distance from the culminated point of odontoid process to the interstitial line between odontoid process and atlas/the distance from the culminatedpoint of odontoid process to the inferior border of atlas was 0.50-0.60, if this ratio was more than 0.65, it would be diagnosed as congenital atlantoaxial dislocation; if this ratio was more than 0.70, it would be diagnosed as basilar invagination. 9. We could individually observe morphologic change and displacement of atlantoaxial vertebrae in the patient with congenital atlantoaxial dislocation, and individually measure by 3D-CT; we could individually observe morphologic change of atlantoaxial vertebrae in the patient with basilar invagination and measure the distance from the culminated point of odontoid process to Chamberlain line and the distance from the culminated point of odontoid process to McRae line, these measure results were -7.9mm±1.5mm and-4.9mm±1.7mm respectively.Conclusions1. While the posterior arch of atlas is typical, the vertical needling point would be located in the midpoint of posterior arch of altas between obvious descending part and near horizontal part; while the posterior arch of atlas is not typical, the vertical needling point would be located in midpoint of posterior arch of altas (the distance from midpoint of posterior arch of altas to posterior median line is 18mm, it couldn't be less than 14mm inwardly and couldn't be more than 22mm ectadly). The introversion needling point would be located in the midpoint of posterior arch of altas between near horizontal part and connective part.2. Most vertical needing technology of altas pedicle screw fixation is feasible, needling depth of this technology is 28mm approximately, the needling direction would be upward about 5 and wouldn't be introversion, the limiting factor is the height of the thinnest part of posterior arch of altas. Introversion needing technology of altas pedicle screw fixation is feasible too, needling depth of this technology is 24mm approximately, the needling direction would be inward about 5°and wouldn't be upward, the limiting factor is exposure latitude, introversion angle and injury to the periphery tissue. 3. Needling technology of axis pedicle screw fixation is feasible , needling depth of this technology is 28mm approximately, the needling direction would be inward about 15°and upward about 35°.4. It must be remarked for operator that the os integumentale was thickness and cancellated bone was thinness in pedicle part of atlantoaxial vertebrae.5. The screw of vertical needing technology of altas pedicle screw fixation, introversion needing technology of altas pedicle screw fixation and needling technology of axis pedicle screw fixation has the same power to resist extraction. The stability of atlantoaxial vertebrae that fixated by atlantoaxial atlantoaxial pedicle screw fixation with needling 3/3 is sufficient, so it isn't essential to exceed the os integumentale.6. The ratios of SAC/sagittal diameter is one of diadynamic criteria for congenital atlantoaxial dislocation or basilar invagination, it could be reflected and assessed the severity of spinal cord or nerve injury for congenital atlantoaxial dislocation and basilar invagination.7. The central atlas angle is one of diadynamic criteria for congenital atlantoaxial dislocation, it could be reflected and assessed the severity of spinal cord or nerve injury for congenital atlantoaxial dislocation.8. The interstitial line between odontoid process and axis is an important anatomic marker. The ratios of the distance from the culminated point of odontoid process to the interstitial line between odontoid process and axis/the distance from the culminated point of odontoid process to the inferior border of axis is one of diadynamic criteria for congenital atlantoaxial dislocation and one of diadynamic criteria for basilar invagination.9. Morphologic change of atlantoaxial vertebrae can be individually observed and measured by 3D-CT for congenital atlantoaxial dislocation and basilar invagination, so treatment plan can be provided individually by 3D-CT.
|
PDF Full Text Request