Radiolographic study of relationship between vertebral artery and transverse foramen in lower cervical spine

English Keywords:Vertebral artery  Transverse foramen  Lower cervical spine  CT angiography

English Abstract:

  【Abstract】 Objective：To investigate the relationship between vertebral artery and transverse foramens in lower cervical spine and to explore the risk of vertebral artery injury due to pedicle screws implantation.Method：Fifty patients（28 males，22 females） screened by computer tomogram angiography（CTA） were included in our series，patients with cervical spine and vertebral artery abnormality were excluded.Several parameters were measured bilaterally on the cross-sectional image of C3 to C7 including the maximal width（W） and height（H） of transverse foramen，the diameter of vertebral artery（AL），the shortest distance between vertebral artery and medial（M），lateral（L），anterior（A） and posterior（P） border of transverse foramen，the shortest distance between vertebral artery and pedicle（h），the area of vertebral artery（AVA） and transverse foramen（AF），and the rate between AVA and AF（AVA/AF） were measured respectively.Result：No difference had been find between right and left side in same segment either in males or in females（P>0.05）.No significant difference was noted between males and females except of M in C5 and L in C6（longer in males than in females）.W，H and AF increased from C3 to C6.However，C7 had the lowest H and AF.M was lower than L at C3-C6（P<0.01）.A was lower than P at C3，C4 and C5，however a little bit longer than P at C6.h varied from C3 to C7 with the minimun of 0.5±0.2mm at C3 and the maximum of 7.3±2.7mm at C7.AVA/AF decreased from C3 to C6 with the maximum of 35.7％±15.7％ at C3 and the minimum of 27.4％±12.8％ at C6.Conclusion：Relative "abundance space" exists for vertebral artery in transverse foramen.Vertebral arteries locate to the medial part of transverse foramen，and anteriorly in C3，C4 and C5，while posteriorly in C6.The highest risk of vertebral artery injury due to cervical pedicle screw implantation is at C3，secondarily at C6，and the lowest is at C7.