Study On Pedicle Screw Fixation Of Cervical Spine Assisted By Iso-C3D Navigation System Or The Individual MPR Placement Technique

Objective To discuss the accuracy and feasibility of cervical pedicle screwfixation assisted by Iso-C3D navigation system or the Individual MPR PlacementTechnique.Methods There were eight adult cadaver specimens of cervica spine (C1-T1)excluding specimens of osteoporosis by X-ray.The spiral computed tomography scanand MPR reconstruction of4cervical specimens were taken,To determine theentrance spot and direction of placement nails according to CT measurements,Thenappropriate screws were inserted into the C2-C7pedicles individually with the helpwith lateral C-arm fluoroscopy.In the other4human cadaver cervical vertebraes,3.5mm screws were inserted into the pedicles assisted by Iso-C3D navigationsystem.Cortical integrity of every sample was examined by the spiral CT scan.Resultsthirty-eight screws were inserted into pedicle by Iso-C3D navigation system,91.7%of the screws were placed entirely within the pedicle,6.2%showednon-critical breaches, and2.1%showed critical breaches;48screws were placed into pedicle assisted by the Individual MPR PlacementTechnique,70.8%of were placed entirely within the pedicle,12.5%showednon-critical breaches, and16.7%showed critical breaches.Pedicle screw perforation segmental distribution:a total of18screw,C2(0)，C3(8)，C4(5)，C5(3)，C6(1)，C7(1)，where C3、C4accounted for72.2%.Distribution of pedicle screw perforation directions: a total of18screw,the medial(2),lateral(11)，upper(4)，lower(1)，where the lateral accounted for61.1%.there was statistical significance between the accuracy rate of two methods(P<0.05).Conclusion Compared with the Individual MPR Placement Technique,theaccuracy ratio of pedicle screw fixation of cervical spine assisted by Iso-C3Dnavigation system is higher；The imbedding of pedicle screw C3、C4in eachvertebrae of lower cervical spine was with comparatively higher risk,whenimbedding,the angle of screw was partial to the inner side,which was more reliableand safer.