The Degree Of Injury And The Character Of Plain Radiographs And CT In Unilateral Locked Facet Of Cervical Spine

ObjectiveTo approach pacing factor of copying unilateral locked facetthrough study soft tissue injury , to explain the character of plainradiographs and CT using rotary angle in unilateral locked facetof cervical spine.MethodsFour adult cervical spine specimens dipped in formalinincluding C1-T1, stored at -20℃in the ice chest .They defrost 8hat ambient temperature after taked out from the ice chest ,which areeliminated muscular tissue of cervical vertebra, cervical vertebra ,complete remaining supraspinal ligament,interspinal ligaments,flaval ligamentshe and intercalated disc.They are also eliminatedinboard ,backside of double C4-5 articular capsule, injuring lateralpart longitudinal ligament ,except of the outboard articular capsule.The odontoid bone of cervical vertebra is inserded one needle fromeach sagittal axis,frontal axis and vertical axis , inserded aconimeter in rectilinear axes ,which is fixed using des- tooth flour,making C1-4,C5-T1 both are one whole . X-ray and CT aretaken before the experiment.The resistor piecese ,linked to therecorder using guide wires,are sticked in upper side,down side,inboard side and lateral side at double intervertebral foramens.Four couple of screws are inserted up and down at the front ofvertebral body and rear vertebral plate of C4,C5,which is 2㎝ .The rubber slips are sleeved 10 circles to each couple of screwswhich simulates muscle contraction .The X-ray is taken from 0°-200°from interlocking side to the other when the standard is anodicvertebral body.The true lateral position is 00°,the backwardrotation 10°is 10°when the standard is hypostasy vertebral body atinterlocking side.The specimen which is fixed in tailar-made clampis rhaebosised by forced and the center of effort is at the vertebralbody or articular process of C4-5 .The distal end of vertebral bodyare turned round when the articular process of C4-5 is completelyabruptioed,then the model of unilateral locked facet of cervicalspine is simulated. The plain radiographs and CT of unilaterallocked facet of cervical spine are taken and analyzeded.Results The parenchyma injury caused by anteflexion and eddy is moresevere than lateral flexion.ModelⅠ- lateral flexion and eddy :theligament supraspinale and interspinal ligaments are completelybreaked, the right lateral part of flaval ligaments and the part ofanterior longitudinal ligament are breaked ,more than 1/2 of theannular fibrosus is destroied. ModelⅡ- anteflexion and eddy (notsimulate muscle contraction ): :the ligament supraspinale andinterspinal ligaments are completely breaked,a bulk of flavalligaments and anterior longitudinal ligament are breaked, theannular fibrosus is destroyed completely. ModelⅢ- lateral flexionand eddy: the ligament supraspinale and left flaval ligaments arecompletely breaked, a part of interspinal ligaments and anteriorlongitudinal ligament are breaked, more than 1/2 of the annularfibrosus is destroied. ModelⅣ-lateral flexion and eddy: theligament supraspinale and interspinal ligaments are completelybreaked,a part of left flaval ligaments is completely breaked, ,apart of anterior longitudinal ligament is lifted no break , more than1/2 of the annular fibrosus is destroied. The average rotary angle is19.75°in unilateral locked facet of cervical spine.The intervertebral foramens are seen at 0°10°180°190°down the injury plane frominterlocking side to the other when the standard is anodic vertebralbody.The intervertebral foramens are seen at 150°160°00°-10°upthe injury plane .The CT thin scan shows the rotation of vertebralbody ,the naked facet sign , articular process bone fracture etal.The coronal reconstructions show left-right asymmetry ; therestitutions in arrow extent show articular facet interlocking .Notonly the lateral radiograph can find intervertebral foramina of up ordown in injury plane,other position also can find simiarcharacter;CT can find rotary spine,the naked facet sign;coronalplane rebuilding can find asymmetry right and left;sagittal planerebuilding expressly show unilateral locked facet.ConclusionThe inflective and rotary force is necessary to establish unilaterallocked facet of cervical spine,destroying the articular capsule is thekey to establish model and the ipsilateral ligamentum flavum withmore than 1／2 annular fibrosus destroy is necessary,the resistanceof supraspinous and intraspinous ligamnents is small.The affirmation of the angle of rotation offers theory support to thecharacter of X-ray and CT,to replacement of clinical operation.Theexperiment checks and addend with explaining the mechanismsome people's view:The intervertebral foramens are seen at theanodic or inferior parts of injury plane at lateral position,theintervertebral foramen injury plane is bigger . X-ray can earlydiagnose unilateral locked facet of cervical spine.CT and threedimensionalreconstruction can identify final diagnosis it.