| Objective:1.To explore the anatomical basis for the bypass surgery of CCA-VA and ECA-VA from anterolateral cervical approach,through studying the anatomic of the vertebral artery V2 segment and its adjacent structures.To explore how to expose the V2 segment of vertebral artery in safe and effective method.2.To explore the advantages and disadvantages in posterior circulation flow reconstruction surgery blood supplied by ECA and CCA,through studying the anatomical relationship of the ECA branches-superior thyroid artery and vertebral artery V2 segment,and the application prospect of superior thyroid artery in posterior circulation bypass surgery.Methods:1.10 cases adult cadaveric head with the neck(with a total of 20 sides)perfused with colored silicone gel were selected to observe.The V2 segment was exposed by simulating the anterolateral cervical approach.Record steps and hierarchical structure during dissection proceeding;2.20 cases imaging data(40 sides)of cervical spine CTA and three-dimensional reconstruction of cervical spondylosis were selected to observe and record the length,diameter,branch and variation of V2 segment;3.The relationship between the V2 segment and the surrounding tissue was summarized according to the cadaveric head specimens and three-dimensional reconstruction images;4.The initiation site of superior thyroid artery of external carotid artery branches at vertebral artery dominance side(balance for left)and the corresponding vertebral level position were detected,and the distance to the superior pole length,diameter.Measurement of the distance between the beginning of the superior thyroid artery and the V2 segment on the superior side of the vertebral artery in the cervical spine with CTA..Results:1.The structure of V2 segment from anterolateral cervical approach: the skin,subcutaneous fat,platysma,the sternocleidomastoid muscle,the prevertebral fascia,collilongus,the transverse process,the vertebral artery.2.The V2 segment from C6 transverse foramen was 39 sides,a few from the other transverse foramen,walking bony canals formed in C6-C3 transverse foramen,walking lateral upward along the lower edge of axis vertebral body,and entered the transverse foramen.14 cases of left,2 cases of right.4 cases were dominant balance of power.The diameter of V2 segment was(3.8±1.3)mm,and the diameter of end point was(3.4±1.2)mm,and the length was(70.0±2.1)mm.3.The V2 segment and its surrounding venous plexus are wrapped with transverse periosteal sheath.Ahead the V2 segment is intertransversarii and collilongus,anterolateral C5-C2 is longus capitis muscles,the medial side is adjacent to the Luschka joint,and the posterior is cervical articular process and the posteromedial is foramen intervertebrale.Cervical spinal nerve root from the intervertebral foramen walk behind V2 segment from the back side to the posterior lateral.The main branch of V2 segment is the root of the spinal nerve root.4.4 cases of thyroid artery from a carotid artery,3 cases from external carotid artery,3 cases from the level of carotid artery bifurcation;6 cases from the upper edge of C4;3 cases from the upper edge of C3;1 cases from the upper edge of C3;Diameter is(2.0±0.3)mm,the length to the upper of thyroid gland on is(45.9 ± 6.4)mm,the thyroid extreme diameter is(1.7±0.2)mm,and the distance of V2 segment is(20.8 ±1.9)mm.Conclusion:1.Through the study on microsurgical anatomy of V2 segment of the vertebral artery,can provide anatomical basis for clinical disease related to vertebral artery,and provide new ideas;2.CT three dimensional reconstruction of vertebral artery can make sure the position,shape and the relationship with cervical bone structure and is useful for developing surgical planning,also good to prevent the occurrence of postoperative complications;3.In the operation,the anterolateral cervical approach,between external jugular vein and sternocleidomastoid muscle,bite transverse process bone,can safely and effectively expose the V2 segment;4.The V2 segment has relation with the surrounding muscles,bones,nerves and blood vessels.Familiar with the anatomic relationships in the region can avoid this node injury at clinical operation.5.The diameter of the superior thyroid artery is about 2mm,and the free segment is longer,and it is close to the V2 segment,which can be used as a good supplied vessel for reconstruction of vertebral artery blood flow. |
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