title: Does intraoperative navigation improve the accuracy of pedicle screw placement in the apical region of dystrophic scoliosis secondary to neurofibromatosis type I: comparison between O-arm navigation and free-hand technique.
abstract: To assess the accuracy of O-arm-navigation-based pedicle screw insertion in dystrophic scoliosis secondary to NF-1 and compare it with free-hand pedicle screw insertion technique.
  
  
  
  32 patients with dystrophic NF-1-associated scoliosis were divided into two groups. A total of 92 pedicle screws were implanted in apical region (two vertebrae above and below the apex each) in 13 patients using O-arm-based navigation (O-arm group), and 121 screws were implanted in 19 patients using free-hand technique (free-hand group). The postoperative CT images were reviewed and analyzed for pedicle violation. The screw penetration was divided into four grades: grade 0 (ideal placement), grade 1 (penetration <2 mm), grade 2 (penetration between 2 and 4 mm), and grade 3 (penetration >4 mm).
  
  
  
  The accuracy rate of pedicle screw placement (grade 0, 1) was significantly higher in the O-arm group (79 %, 73/92) compared to 67 % (81/121) of the free-hand group (P = 0.045). Meanwhile, a significantly lower prevalence of grade 2-3 perforation was observed in the O-arm group (21 vs. 33 %, P < 0.05), and the incidence of medial perforation was significantly minimized by using O-arm navigation compared to free-hand technique (2 vs. 15 %, P < 0.01). Moreover, the implant density in apical region was significantly elevated by using O-arm navigation (58 vs. 42 %, P < 0.001).
  
  
  
  We reported 79 % accuracy of O-arm-based pedicle screw placement in dystrophic NF-1-associated scoliosis. O-arm navigation system does facilitate pedicle screw insertion in dystrophic NF-1-associated scoliosis, demonstrating superiorities in the safety and accuracy of pedicle screw placement in comparison with free-hand technique.
authors.affiliation: Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road No. 321, Nanjing, 210008, China.
authors.forename: Mengran
authors.initials: M
authors.lastname: Jin
authors.affiliation: Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road No. 321, Nanjing, 210008, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road No. 321, Nanjing, 210008, China.
authors.forename: Xingyong
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road No. 321, Nanjing, 210008, China.
authors.forename: Huang
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road No. 321, Nanjing, 210008, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Han
authors.affiliation: Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road No. 321, Nanjing, 210008, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Qiu
authors.affiliation: Department of Spine Surgery, Drum Tower Hospital of Nanjing University Medical School, Zhongshan Road No. 321, Nanjing, 210008, China. zhuzezhang@126.com.
authors.forename: Zezhang
authors.initials: Z
authors.lastname: Zhu
mesh_terms: D006801:Humans; D009456:Neurofibromatosis 1 / Q000150:complications*; D019637:Orthopedic Procedures / Q000379:methods* / Q000706:statistics & numerical data; D065289:Pedicle Screws; D012600:Scoliosis / Q000000981:diagnostic imaging* / Q000209:etiology / Q000601:surgery*; D013131:Spine / Q000000981:diagnostic imaging / Q000601:surgery; D025321:Surgery, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data
keywords: Accuracy; Neurofibromatosis type I; O-arm navigation; Pedicle screw