Application Of Intra-operative Three Dimentional CT Navigation Forsurgical Correction Of Spinal Deformity

Objective:To explore the results and clinical value of intra-operative computed tomography (iCT) navigation in pedicle screw insertion accuracy in comparison to screw placement without navigation in spinal deformity surgery.Methods:From 2009 to 2012, clinical data about 100 patients underwent surgical deformity correction with assistance of iCT were included. All cases were divided into 2 groups:navigation group (n=37), and non-navigation group (n=63). Grouping methods: 1) In each group, all screws were divided according to the spinal segment (thoracic vertebrae, upper/middle/lower thoracic vertebrae, lumbar vertebrae).2) According to the magnitude of vertebral rotation(Gl=0°,0°< G2≦ 10°,10°< G3≦20°, G4> 20°), all screws of each group were divided into 4 subgroups (G1 in navigation/non-navigation group was represented as G1N/G1F group, and so on). After all screws placement completed, iCT scan was taken and three dimensional reconstruction technology was applied to assess accuracy of each screw. Grade Ⅱ and Ⅲ screws were defined as malposition and needed revision. Broken screws rate, malposition and revision rate of each group were calculated and analyzed.Results:There were 37 patients in navigation group including 19 males and 18 females with an average age of 25.03 ± 18.58 years ranging from 3 to 77 years, and in non-navigation group,28 males and 35 females with a total of 63 patients were included with an average age of 18.87±12.04 years ranging from 3 to 63 years. No significant difference was found in age and sex between 2 groups(Page=0.5291, Psex=0.1307). Compared with non-navigation group, there were a higher accuracy rate and a lower revision rate of total pedicle screws placement in navigation group. The screws insertion accuracy rate of thoracic pedicle screws, middle and lower thoracic screws in navigation group is higher and the revision rate is lower than that of non-navigation group. However, significant difference was not found in upper thoracic and lumbar pedicle screws. The statistical result showed no significant difference in broken screws rate, malposition and revision rate between G1N and G1F, and so was it between G1N and G1F(P>0.05). However, it was suggested that lower broken screws rate, malposition and revision rate existed in G3N and G4N, compared with in G3F and G4F (P<0.05).Conclusion:The iCT navigation system provides a high accuracy of pedicle screw placement in surgical correction of spinal Deformity, especially in thoracic spinal instrumentation, and when vertebral rotation degree exceeds 10°...