Treatment Of Atlas Fracture By Operation Under ISO-C-3D Navigation And It's Clinical Significance

Objective:To evaluate the preliminary clinical outcome of the ISO-C-3D navigation system used in the treatment of atlas fracture by operation and discus it's clinical significance.Methods:From May 2007 to August 2010,22 patients with atlas fractures were treated with screw fixation under the guidance of an ISO-C-3D navigation system. The group included 16 males and 6 females,35 years old on average (range from 19 to 46 years); 9 of them were traffic injury,and 13 of them were fall injury. According to Levine classification,9 atlas fractures were of GradeⅠ(3 had GradeⅢOdontoid fracture),7 atlas fractures were of GradeⅡ(1 had C2 laminal fracture),6 atlas fractures (Jefferson fracture) were of GradeⅢ(2 had fractures of the lateral mass). Fractures of GradeⅠunderwent C1 lateral mass and C2 pedicle screw fixation, fusing C1-C2 with posterior bone graft; fractures of GradeⅡandⅢunderwent occipitocervical fusion. All the patients were examined by X-rays and CT after operation.Results:70 pedical screws and 18 lateral mass screws were inserted under ISO-C-3D navigation. On the average, every screw needed 1.8 minutes to be inserted. Of the 70 pedical screws inserted,68 pedical screws (97.7%) were classified as Grade 1(no pedicle perforation),2 pedical screws (2.3%) were classified as Grade 2(screw perforation of the cortex by up to 2mm), no pedical screws (0%) were classified as Grade 3 screw perforation of the cortex> 2mm); None of the 18 lateral mass screws showed evidence of foramen transversarium, neural foramen, or facet joint violation. The average time of each pedical screws was 1.8min(1.2-3.1min); The average time of registration was 3.5 min(2-8 min); The average time of the image acquisition and transmission was 7.8min (7.2-8.3min); The average time of the operation was 3 hours; The average bleeding was 290 ml (240～350ml). The period of follow-up 6 months. Solid union of the odontoid process was achieved in all patients and the union time was 4-11 months.Conclusions:The atlantoaxial pediele screw system has the visible biomechanical advantage in the treatment of upper cervical injury,and assistance with ISO-C-3D navigation system, it makes more precise, safe, time-saving and less X-ray exposure to do cervical pedical screw fixation, it is favourable toward the clinical use and promotion of the technology.