The Research Of The Effcet Of Occipitocervical Fusion On Subaxial Cervical Curvature In Patients With Craniocervical Junction Malformations

BackgroundThe surgery aim for Craniocervical junction malformation is to relieve the pression of the bone and soft tissue, and reconstruct the stability of the occipitocervical area. Occipitocervical fusion is one of the mian treatments for Craniocervical junction malformation.The significant effect was reported by many scholars,however,the change of subaxial cervical curvature after operation was reported and taken seriously.lt has not been reported the reserch about the relationship in Craniocervical junction malformation between occipitocervical fixation angle and subaxial cervical curvature after operation in the literature.ObjectiveThe reaserch try to find the relationship in Craniocervical junction malformation between occipitocervical fixation angle and subaxial cervical curvature after operation by measure the X-ray of healthy person and patient with Craniocervical junction malformation.The rerult of the optimum fixed angle will be helpful for the operation of Occipitocervical fusion in Craniocervical junction malformation. Methods77cervical lateral X-ray were collected,wich including50healthy person and27patient with Craniocervical junction malformation.The angle of Oc-C2and C2-C7were measured respectively. The O-C2angle represents the angle between the McGregor’s line and the inferior endplate of C2. The C2-C7angle represents the angle between the inferior endplates of C2and C7. We define the angle of Oc-C2is Occipitocervical angle and the angle of C2-C7is subaxial cervical curvature.Lordosis was recorded as a positive value while kyphosis as a negative value.Results:1.①The mean Oc-C2angle was17.6°±4.4°in females, significantly larger than14.1°±5.3°in males(P<0.05). The mean C2-C7angle was22.1°±8.5°in females and28.2°±12.9°in males. There was no significant difference between males females in C2-C7angle (P>0.05).②There were significant negative correlations between Oc-C2and C2-C7angles in male and female(r=-0.485in male,r=-0.502in female; P=0.022in male,P=0.007in female;).③The mean Oc-C2angle was16.0°±5.1°and the mean C2-C7angle was24.8°±11.0°in50healthy person. There were significant negative correlations between Oc-C2and C2-C7angles in50healthy person(r=-0.514,P=0.000).2.①The mean Oc-C2angle in Craniocervical junction malformation before surgery、immediately after surgery and at the final follow-up were5.3°±11.0°,16.3°±11.2°,16.0°±8.7°respectively. The mean C2-C7angle before surgery、 immediately after surgery and at the final follow-up were29.8°±15.5°,20.0°±14.4°,24.1°±19.6°respectively.②There was significant difference between healthy person Oc-C2angle and Oc-C2angle in Craniocervical junction malformation before surgery.(P=0.000);There was no significant difference between healthy person C2-C7angle and C2-C7angle in Craniocervical junction malformation before surgery.(P=0.103)③There was no significant correlations between Oc-C2and C2-C7angles in Craniocervical junction malformation before surgery (P=0.682, r=-0.083); There was significant correlations between Oc-C2and C2-C7angles in Craniocervical junction malformation at the final follow-up (P =0.000, r=-0.663).④There was significant difference among goup A、goup B and goup C(P=0.003、P=0.015、P＝0.000); There was no significant difference between C2-C7angles at the final follow-up in goup A and C2-C7angles in healthy person (P=0.692); There was significant difference between C2-C7angles at the final follow-up in goup B、C and C2-C7angles in healthy person (P=0.000、P=0.000)Conclusion:1.There was a significant negative correlation between Occipitocervical angle and subaxial cervical curvature in male and female for healthy person.2.The normal Occipitocervical angle and subaxial cervical curvature for healthy person were16.0°±5.1°and24.8°±11.0°3.Occipitocervical angle fixed in Occipitocervical fusion operation for Craniocervical junction malformation shoud be kept in normal range. As occipitocervical angle decreases, the postoperative lordosis at the subaxial cervical spine become lager. As occipitocervical angle increases, the postoperative lordosis at the subaxial cervical spine become smaller even kyphosis.