Surgical Treatment Of Instable Craniovertebralanomalies With Difficult In C2Pedicle Screw Insertion

ObjectiveTo study the screw insertion skills and the posterior surgical reductionplanning of instable craniovertebral anomalies with difficult in C2pediclescrew insertion and to explore its efficacy.Methods41patients suffered from instable craniovertebral anomalies withdifficult in C2pedicle screw insertion were treated at our department. Allpatients underwent posterior decompressed reduction and occipito-vertebralisthmus of axis-lateral mass of C3（Oc-C2-C3）screw titanium rod systeminternal fixation. CT thin layer scanning,3D CT reconstruction and CTAwere performed to determine the difficult degree of C2pedicle screwinsertion and the Feasibility of above surgical treatment. Pre and post operative atlanto dental interval (ADI), Chamberlain’s line(CL) distanceand McRae’s line (ML) distance were measured. The degree of spinal cordcompression wasevaluated by cervicomedullary angle (CMA). JapaneseOrthopaedic Association (JOA) score was used toassess the improvement of cervical medullary function.Results129screws were inserted into the vertebral isthmus of C2and the lateralmass of C3in all41patients, with no injury of vertebral artery and cervicalspinal cord.6-24months（24±6months） were followed up after operation.There was significant statistical difference between the preoperation andpostoperation in reduction of odontoid, compression of spinal cord andimprovement of neurological function（P<0.01）. To date, allfollowing-up patients got well bony fusion, with no loosened screw orbreakage of screw and no redislocation.Conclusionsposterior decompressed reduction and occipito-vertebral isthmus ofaxis-lateral mass of C3（Oc-C2-C3）screw titanium rod system internalfixation for the treatment of instable craniovertebral anomalies with difficultin C2pedicle screw insertion is safe, feasible and effective.