An Imaging And Ralated Clinic Research On Development CI Cannal Stenosis

BackgroundCervical spinal stenosis is a disease characterized by decreased cervical spinal canal volume,spinal cord or nerve compression caused by various reasons,decreased limb sensation,decreased limb motor function,and even abnormal urine and feces function and breathing.Generalized cervical stenosis includes upper cervical stenosis and lower cervical stenosis.The former refers to cervical spinal stenosis above C2 level,while the latter refers to cervical spinal stenosis below C2 level.Clinically,there are many studies on spinal stenosis in the lower cervical spine,and there are relatively mature diagnostic criteria,surgical principles and methods.Spinal stenosis of the lower cervical spine can generally be measured and diagnosed by cervical X-ray or cervical CT.It is generally considered that the sagittal diameter of the lower cervical spine is greater than 14mm,and the relatively narrow diameter of 12-14mm and the absolute narrow diameter of less than 12mm.However,there are relatively few clinical and basic studies on cervical spinal stenosis of the upper cervical spine plane.We know that the anatomical structure of the craniocervical junction is composed of skull base,atlas,axis and other bone structures.The atlas is located in the craniocervical junction,which is connected to the occipital floor through the upper lateral mass joint,and to the axis through the atlantoaxial lateral mass joint and the atlantodontic joint.Compared with the lower cervical spine,the atlantoaxial planar spinal canal is relatively wide,and the atlantoaxial spinal canal has a large buffer gap.So the cranial neck border area developmental atlas vertebra canal stenosis patients is a rare relative to the lower cervical stenosis patients.The overall shape of the atlas is annular,and its anatomical structure is composed of the lateral atlas masses on both sides and the anterior and posterior atlantoaxial arches connecting the bilateral lateral atlas masses.In the embryonic period,atlas of the vertebral body originated in section 4 of the original pillow and 1 sclerotome cervical spine.At about 7 weeks of embryonic development,three primary ossification centers are formed.One ossified center develops into a anterior arch,and the other two form lateral masses on either side.Atlanto-axial vertebral arch after generally no single ossification center,but by the lateral extension part of the formation of the back,on both sides of atlas lateral backward extension of atlanto-axial after vertebral arch to the midline together gradually,basic together at birth,leaving only a few millimeters of cartilage bone seam,after ossification after the formation of atlas nodules.Abnormal development of atlas can cause posterior arch deformity,collapse,lateral mass hypertrophy and other pathological changes,which can lead to spinal stenosis in the atlas plane.Therefore,the abnormal development of atlas during the embryonic period is an important reason for the development of atlas stenosis.Because the incidence of developmental atlantospinal stenosis is not high,most of the literatures are in the form of case reports,and the cases are scattered,so it is difficult to focus on the study of this disease,and there are no major case reports at home and abroad.At the same time,developmental atlantospinal stenosis is located in the cranio-cervical junction area,which can lead to high cervical spinal cord compression and cause clinical symptoms of high spinal cord injury.After the onset of the disease,the symptoms are often progressive aggravation,and failure to timely diagnosis and treatment may endanger the life of patients.Therefore,the study on developmental atlantospinal stenosis is great significance.Objective1.To investigate the imaging characteristics and diagnostic criteria of developmental atlantospinal stenosis through the measurement and analysis of relevant anatomical parameters of normal population and patients2.Through the developmental atlas atlas morphological characteristics in patients with cervical stenosis research,preliminary establish developmental atlas the pathological classification of cervical stenosis3.Through the analysis of the image data,surgical methods and curative effects of the patients with developing atlantospinal stenosis in craniocervical junction.To summarize the clinical characteristics and surgical strategies of developmental atlantoaxial stenosis and explore the influence of different surgical methods on prognosis.MethodsFrom January 2010 to May 2018,29 patients who presented symptoms due to atlas plane spinal cord compression and received surgical treatment in our department were selected for cervical CT and MRI imaging data,and 37 healthy volunteers without abnormal cervical vertebral structure were selected(patient age:25-65 years old;The height of the patient was 150-168cm.The corresponding data were obtained by cervical CT and cervical MRI for comparative study.The measured parameters included:anteroposterior diameter of the odontoid,effective atlas canal diameter?SCD?,anterior media arch thickness,posterior media arch thickness,IAPD,and CSA and occupied area of the odontoid on this plane to reflect the effective atlas canal area?ECSA?of the atlantospinal volume in the plane of the atlantoid.According to the measurement results,the diagnostic reference value of developmental atlantospinal stenosis and the reference value of atlas parameters in normal population are preliminarily determined.The characteristics and classification of atlas developmental deformity were observed and described,and the pathological classification of developmental atlas stenosis is preliminarily established.Based on the pathological classification of atlantoaxial stenosis,the corresponding surgical treatment is performed to evaluate the surgical effectResultThe atlantospinal canal area?CSA?of the diseased group and the normal group are?710.15± 131.80?mm2 and?795.60±13.20?mm2,respectively.The effective area?ECSA?of the atlantospinal canal and spinal cord is?535.07±125.46?mm2 in the diseased group and?661.36±103.71?mm2 in the normal group,respectively.The anteroposterior and anteroposterior diameters?IAPD?of the atlas are?24.14±4.08?mm and?29.46±1.75?mm,respectively.The effective Atlas diameter?SAC?of the diseased group and the normal group are?10.36±3.35?mm and?16.16±1.84?mm,respectively.The Atlas anteroposterior diameter of the diseased group and the normal group are?39.78±4.60?mm and?44.18±2.47?mm,respectively.The thickness of the anterior sagittal atlas arch in normal adults is?6₉5±1.31?mm.In normal adults,the median sagittal plane atlas posterior arch thickness is?6.13±2.17?mm,and the tooth process area is?137.40±25.41?mm2in normal adults.There are significant differences between the indexes of atlas developmental stenosis and those of normal adults.According to the measured data,atlas developmental stenosis is classified,and on the basis of classification,the prognosis of patients with atlas developmental stenosis is good.2.According to the morphological study of atlantoaxial canal stenosis,atlantoaxial canal stenosis can be roughly divided into the following types:?1?small atlas type:in this type of patients,the overall development of the atlas is stunted,and all the diameter lines of the atlas reduce the proportion of the shape of the atlas,resulting in reduced atlantoaxial vertebral canal volume and spinal stenosis?2?atlas posterior arch hypertrophy type:in such patients,the anteroposterior diameter and spinal canal volume of atlas are reduced due to the development and hypertrophy of atlas posterior arch.?3?atlas posterior arch depression type:this type of patients often due to atlas posterior arch poor closure,central collapse deformity caused by atlas anterior and posterior diameter reduced,reduced spinal canal volume;?4?large odontoid fat:this kind of patients atlas itself can develop normally,but due to the combination of axial odontoid hypertrophy,caused by the sagittal diameter of the atlas vertebral canal reduction and the formation of the atlas canal stenosis.3.According to the imaging characteristics and classification of developmental atlantoaxial stenosis,we established a preliminary surgical strategy:?1?atlas posterior arch hypertrophic type spinal stenosis patients suitable for atlas posterior arch resection thin replantation;?2?atlas posterior arch indenting type spinal stenosis is suitable for posterior arch atlas resection,?3?large dentoid fertilizer is suitable for atlantovertebral posterior arch resection or internal fixation via oral process molding;?4?atlantospinal canal developmental stenosis combined with instability suitable for posterior decompression occipital cervical fusion or through oropharyngeal odontoid resection decompression,atlantoaxial fixation.On the basis of classification,surgical treatment of developmental atlantospinal stenosis was performed,and good clinical results were obtained.Conclusion1.Atlantoaxial canal developmental stenosis can reduce the effective volume of the planar atlantovertebral canal and cause spinal cord compression,causing clinical symptoms similar to cervical spondylotic myelopathy.In this study,it was found that atlantoaxial canal stenosis can be caused by various developmental deformity factors,including congenital small atlantovertebral deformity,posterior arch hypertrophy or lacunae deformity,lateral mass developmental hypertrophy deformity of atlantovertebra,and odontoid developmental hypertrophy deformity.2.According to the morphological study results of atlantoaxial canal stenosis,developmental atlantoaxial stenosis can be roughly divided into 5 pathological types.3.According to the imaging characteristics and classification of developmental atlantoaxial stenosis,appropriate surgical treatment can achieve better surgical results.