Pressure variation of facet joint following cervical total disc replacement anterior cervical discectomy and fixation

English Keywords:Cervical spine  Cervical total disc replacement  Fixation  Pressure sensitive film  Biomechanics

English Abstract:

  【Abstract】 Objective：To measure the pressure variation of facet joint after cervical total disc replacement（TDR） anterior cervical discectomy and fixation（ACDF），and explore mechanical effect for cervical facet joint following two operations.Method：A total of 6 adult human fresh cervical spinal specimens（C2-C7） were divided into intact cervical specimens group，TDR group and ACDF group.Following intact specimens analysis，all specimens were sequentially reconstructed at C4-C5 segment with TDR and ACDF.Pressure sensitive film was put into left-side facet joints of C4-C5 segment.Firstly a 75N follower load was applied，then a three-dimensional movement was performed with the continous load.Pressures of facet joint were measured in 0Ｎ·ｍ and 2.0Ｎ·ｍ（flexion/extension，left/right lateral bending），4.0Ｎ·ｍ moment（left/right axial rotation）.Result：To compare with the pressure of left-side facet joint in neutral position，pressure of facet joint of intact specimens and TDR increased significantly in extension，left lateral bending and right axial rotation （P<0.05），but not obviously changed in flexion，right lateral bending and left axial rotation.In contrast with intact specimens and TDR，the pressure of facet joint of ACDF were not significant between in neutral position and any motions（P>0.05）.In the comparison among three tested groups，the pressure variation of facet joint was similar between intact specimens and TDR.The pressures of facet joint of ACDF were obviously decreased in extension，left lateral bending and right axial rotation，but there were not significance among three groups（P>0.05）.Conclusion：Pressure variation of facet joint is not significant between TDR and intact specimens.It indicates that cervical total disc replacement can effectively restore normal physiological pressure of cervical facet joint.