ABSTRACT
Objective To explore the technique and clinical outcome of the atlantoaxial pedicle screw system in the treatment of the unstable atlantoaxial dislocation post traction.Methods The study involved 32 patients with atlantoaxial dislocation(type T2 of TOI classification)admitted from March 2005 to September 2009.There were 17 patients with fresh odontoid fracture and two with old odontoid fracture,five with traumatic disruption of the transverse atlantal ligament and eight with congenital odontoid dysplasia.JOA scores of neurological function before operation was at a range of 5-13(average 8.38).The average of space available for the cord(SAC)was 9.15 mm.Before the atlantoaxial pedicle screw system was carried out,the skull traction was performed in all the patients preoperatively.Results A total of 128 pedicle screws were inserted safely,with mean operation time and perioperative blood loss for 1.5 hours and 300 ml,respectively.No injury to the vertebral artery or spinal cord was observed.All the patients were followed up for 12-24 months,which showed that JOA scores one year after operation was increased to 10-17(average 14.56),with the improvement rate of 71.70%,and that the SAC was average 14.86 mm.The X-ray and SCT scans verified the proper position of the screws,with no internal fixation failure or atlantoaxial redislocation.After 3-6 months,all the patients except for one patient achieved a solid bone fusion.One year after operation,the one patient with no bone graft fusion was removed of the internal fixation system and obtained satisfactory restoration of the rotational function.Conclusions Atlantoaxial pedicle screw system is an effective method for the treatment of the unstable atlantoaxial dislocation post traction,for it has the advantages of stable three-dimension fixation,direct screw placement,intraoperative reduction and high fusion rate.