The Application Of An Occipitocervical X-ray Assessment Methods In The Treatment Of Atlantoaxial Dislocation

Objective: To explore a simple X-ray assessment methods in the diagnosis andtreatment of atlantoaxial dislocation feasibility and clinical application value throughretrospective study.Methods: Selected in the First People’s Hospital of Chenzhou City in January2007-2012in December,who confirmed atlantoaxial dislocation as dislocation group(A group), including23males and17females, aged25to60years old, average42.67±10.58, according to MRI data is divided into A1: presence of cervical spinalcord compression; A2: absence of cervical spinal cord compression. Randomlyselected180patients without cervical disease, as a normal group (B group), including102male cases,78female cases, aged18to75years old, with an average of50.23±12.96years. The group A1preoperative and final follow-up JOA score forcomparison; measured preoperative, intraoperative and postoperative radiographicparameters: take atlas anterior tubercle vertices A and posterior tubercle vertex P do astraight line, straight line along vertebral axis trailing edge, the two straight linesintersect at the opening to the front angle is angle, the atlas anterior tubercle verticesA and posterior tubercle vertex P of connection, and the vertebral axis trailing edgeextension cords intersect at point O, measure AO/PO value. The angle and AO/POvalue for all subjects were determined by two doctors independently. The procedurewas repeated two weeks later in a different and randomly assigned order．Percentageof agreement and Kappa coefficients were used to determine the intraobserver andinterobserver reliability. The various indicators for statistical analysis.Results: JOA score of Atlantoaxial dislocation patients with the spinal cordcompression group (A1)8.63±2.04preoperative, postoperative13.75±1.59, comparedto a significant difference (P<0.05). angle: no cervical disorders group (B)98.33°±3.99°, A1preoperative79.83°±18.67°, postoperative95.00°±8.60°.Atlantoaxial dislocation patients with no spinal cord compression group (A2) preoperative97.69°±4.00°, postoperative96.88°±3.63°; AO/PO value: B0.57±0.06,A1preoperative3.17±4.52,1.01±0.57after surgery, preoperative A20.97±0.18,0.57±0.06after surgery. It was reliable of angle and AO/PO value measurement,pair-wise interobserver and intraobserver agreement(weighed Kappa) weregood(Kappa>0.6). The angle, AO/PO value of A1preoperative and postoperativecompared to a significant difference (P<0.05), AO/PO value of A2preoperative andpostoperative compared to a significant difference (P<0.05), between preoperativeand postoperative angle, there was no significant difference (P>0.05); A1groupwith the A2group of patients surgerybefore, before surgery the A1group of patientswith group B angle relative comparison was significant difference (P<0.05), the A2group of patients surgerybefore with group B angle phase comparing was nosignificant difference (P>0.05), A1, A2group surgery before and the group B AO/POvalue comparison was significant difference (P<0.05), A1group with the A2groupsurgery before AO/PO value relatively free significant difference (P>0.05); A1, A2group postoperative angle with the B group of relatively non-significant difference(P>0.05), group A1postoperative AO/PO value with group B phase comparison,there was significant differences (P<0.05), the A2group surgeryafter AO/PO valueand B group compared with no significant difference (P>0.05); A1preoperative andthe the group A2postoperative angle, AO/PO value compared were significantdifferences (P<0.05), the A1group surgeryafter group and the A2preoperative angle, AO/PO values were not significantly different (P>0.05). A1group surgeryafterand A2group postoperative angle showed no significant difference (P>0.05),AO/PO value were significant difference (P<0.05).Conclusion:1. angle and AO/PO value can effectively determine atlantoaxialdislocation, intraoperative able to effectively guide the reset;2.The atlantoaxialdislocation surgery reset to angle of about95°, the AO/PO value of about1.01canbe effectively relieve spinal cord compression, to achieve a good clinical efficacy.