CT Imaging Study And Clinical Significance Of Transverse Foramen In The Cervical Vertebrae

Obejective:To determine the variability of transverse foramen of cervical vertebra by measuring the track lines of the transverse foramen on CT images, and to understand the importance of preoperative conventional CT examination in the prevention of intraoperative vertebral artery injury.Method:CT images were collected in Shaoxing county central Hospital in2010to2012. The relationship between the outer edge of vertebral body and the inner edge of transverse foramen was classified into the extra-vertebra (Type A), the intermediate (Type B) and the intra-vertebra (Type C). Morphometric measurements of transverse foramen and adjacent structures were acquized on CT images, including transverse diameter, sagittal diameter, the transverse foramen inner margin distance, distance between the inner edge of the transverse foramen and the vertebral body midline.distance between the inner edge of the transverse foramen and the outer edge of the vertebral body.and the shortest distance between the inner edge of the transverse foramen and the spinal canal. Data were analyzed using SPSS.Result:(1) Among the subjects studied,83.3%was classified as type A foramen,16.4%was classified as type B foramen and0.29%was classified as type C foramen.(2) Transverse foramen aperture diameters of the measurement results showed as following: for the left foramen,the tranverse diameter was0.68±0.19cm, the saggital diameter was0.56±0.18cm, the distance between the inner edge of the transverse foramen and the outer edge of the vertebral body was0.14±0.20cm, the distance between the inner edge of the transverse foramen and the vertebral body midline was1.30±0.28cm,and the shortest distance between the inner edge of the transverse foramen and the spinal canal was0.48±0.18cm; for the right foramen, the tranverse diameter was0.65±0.17cm, the saggital diameter was0.53±0.17cm, the distance between the inner edge of the transverse foramen and the outer edge of the vertebral body was0.16±0.21cm, the distance between the inner edge of the transverse foramen and the vertebral body midline was1.28±0.30cm, the shortest distance between the inner edge of the transverse foramen and the spinal canal was0.46±0.18cm; the transverse foramen inner margin distance was2.57±0.18cm.(3) For both C4and C5vertebra,the saggital distance of left foramen was greater than that of right foramen.For the distance between the inner edge of the transverse foramen and the vertebral body midline,The value of C3was smaller than that of C5, the value of C5was smaller than that of C6and the value of C4was smaller than that of C5; For the transverse foramen inner margin distance and the shortest distance between the inner edge of the transverse foramen and the spinal canal, the results were the same. All the difference were significant.Conclusion:(1) Except for C3, C4vertebrae,the transverse foramen inner margin distance and the shortest distance between the inner edge of the transverse foramen and the spinal canal at C3-C6vertebral body gradually increased;(2) In rare cases, the transverse foramen was crossed into the lateral edge of the vertebral body;(3) The pre-operative examinations should be carefully checked before doing anterior cervical spine surgery as to avoid intraoperative vertebral artery injury, and help guide the surgery.