| Chapter 1 (section 1) Construction of an efficient expression vector for soluble leptin receptor of adolescent idiopathic scoliosisObjective. To construct the efficient lentiviral vectors of human soluble leptin receptor (sOB-R) gene and determine the lentiviral titer.Methods. The sequence of sOB-R gene was properly designed and the primers were also synthesized. Then, the target gene sequence was cloned to pHBLV-CMVIE-IRES-Puro to construct a recombinant vector, after which the sequence was further screened and confirmed. After that, the new recombinant sOB-R/pHBLV-CMVIE-IRES-Puro vector was transferred into the 293T cells for the packaging of lentivirus. Furthermore, the virus titer was determined.Results. The lentivirus vector of sOB-R gene was successfully synthesized, and the specificity of the target gene sequence was confirmed. Moreover, the lentivirus titer was qualified for the further investigation.Conclusions. The construction of lentivirus vector for sOB-R gene was satisfactory, which would be useful for further investigation.Chapter 2 (section 1) learning curve of pedicle screw insertion using O-arm navigation system in adolescent idiopathic scoliosisObjective. To investigate the learning curve of pedicle screw placement in adolescent idiopathic scoliosis (AIS) surgery by using O-arm navigation.Methods 44 patients with AIS who underwent O-arm-navigation-based thoracic pedicle screw insertion were enrolled in the present study. The accuracy of pedicle screw placement was calculated by postoperative computed tomography (CT) scans, and the misplacement was defined as pedicle screws breaking medial, lateral, anterior vetebral cortex more than 2mm.Results A total of 335 screws were implanted at the apical region of the curves, and were divided chronologically into five groups. The overall accuracy of pedicle screw placement was 93.2%(312/335), and 23 screws were found to be misplaced (6.8%). The incidence of thoracic pedicle screw misplacement was significantly higher in the first subgroup (19.4%) than those in other 4 subgroups (P<0.05). Meanwhile, there was no statistically significant difference between the latter 4 subgroups (group 2,3, 4 and 5) in terms of pedicle screw misplacement (P>0.05). Moreover, after the first 67 screw placements, the assessed rates declined significantly and reached to a stable level.Conclusions An experience of at least 67 screw placements is needed for inserting the pedicle screw in AIS surgery by using the O-arm navigation.Chapter 2 (section 2) The accuracy of pedicle screw insertion assisted by O-arm navigation in neurofibromatosis type 1-associated scoliosisObjective. To evaluate the accuracy of pedicle screw placement assisted by O-arm navigation in scoliosis secondary to dystrophic neurofibromatosis type 1 (NF-1).Methods.32 patients with scoliosis secondary to dystrophic NF-1 were classified into two groups.92 pedicle screws were inserted in the apical region of the curves in 13 patients using O-arm navigation system (O-arm group), and 121 screws were inserted in 19 patients by free-hand technique (free-hand group). The postoperative computed tomography (CT) scans were assessed for pedicle perforation. The screw perforation was characterized into four grades:grade 0 (ideal placement), grade 1 (perforation less than 2 mm), grade 2 (perforation between 2 and 4 mm), grade 3 (perforation more than 4 mm).Results. The accuracy of ideal pedicle screw insertion was particularly higher in O-arm group (79%) than 67% of the free-hand group (P=0.045). Also, a lower incidence of grade 2 and 3 perforation was noted in O-arm group (21%) than that of free-hand technique (33%) (P< 0.05). The prevalence of medial violation was particularly decreased with O-arm navigation system (2%) than that of free-hand technique (15%) (P< 0.01). Meanwhile, the implant density increased significantly by using O-arm navigation (58%) than that of free-hand technique (42%) (P< 0.001).Conclusion. The present study demonstrates that O-arm navigation system exhibits significant superiorities in the safety and accuracy of pedicle screw placement in comparison with free-hand technique in dystrophic NF-1-associated scoliosis.Chapter 2 (section 3) The accuracy of small thoracic pedicle screw insertion assisted by O-arm navigation in adolescent idiopathic scoliosisObjective. To assess the accuracy and safety of pedicle screw placement assisted by 3D O-arm navigation system in severe scoliosis surgery.Methods.63 patients with severe adolescent idiopathic scoliosis were divided into two groups. A total of 156 pedicle screws were implanted in apical region (two vertebrae above and below the apex each) in 21 patients using O-arm-based navigation (O-arm group), and 230 screws were implanted in 42 patients using free-hand technique (free-hand group). The accuracy of pedicle screw placement was calculated by postoperative CT scans.Results. The O-arm group comprised 156 screws,91% excellent,9% good, and 0% bad. The free-hand group comprised 230 screws,79.1% excellent,13.1% good, and 7.8% bad. The perforation rate on the concavity of the curve was significantly higher than that on the convexity in both groups (O-arm group:15.2% vs.4.4%, P=0.019; free-hand group:26.9% vs.15.9%, P=0.012). The incidence of medial perforation was significant reduced by using O-arm navigation compared to free-hand technique (2.6% vs.5.2%, P=0.038). Moreover, the perforation rate was not associated with the distance between the instrumented level and the tracker.Conclusion. The accuracy of pedicle screw placement with O-arm navigation system in severe scoliosis surgery can reach 100%, thus providing superiority over conventional free-hand technique in terms of accuracy of pedicle screw insertion. Moreover, low radiation dose and easy operation surpass the free-hand technique.Chapter 2 (section 4) Does O-arm navigation system decrease the postoperative pleural effusion compared to free-hand technique?Objective. To identify whether the O-arm navigation system could diminish the volume of postoperative pleural effusion compared to free-hand technique in adolescent idiopathic scoliosis (AIS) surgeryMethods. A consecutive cohort of 15 AIS patients who had been operated with O-arm navigated system (O-arm group) were enrolled in the current study, and 30 curve matched AIS patients treated by conventional free-hand technique were also included as control group (free-hand group). Postoperative computed tomography (CT) reconstruction images were used to quantify the volume of pleural effusion.Results. The mean ages were 14.2 (range 12-18) and 14.8 (range 11-18) years in O-arm group and free-hand group, respectively. The mean volume of pleural effusion was significantly larger in free-hand group (130.8±81.7 ml vs.22.7±13.2 ml, P< 0.001). The volume was significantly larger in free-hand group than that of O-arm group on the convex side (O-arm:23.7±13.1 ml vs. free-hand:159.8±70.6 ml, P< 0.001), either was that on contralateral side (O-arm:22.3±11.7 ml vs. free-hand:111.8±59.7 ml, P<0.001).Conclusion. The volume of pleural effusion was significantly decreased by O-arm navigation system compared to conventional free-hand technique. The new intraoperative navigation technique does provide an ideal option for AIS patients who have poor pulmonary function. |
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