title: A comparative study on the accuracy of pedicle screw placement assisted by personalized rapid prototyping template between pre- and post-operation in patients with relatively normal mid-upper thoracic spine.
abstract: The aim of this study was to assess the accuracy of rapid prototyping drill template technique for placing pedicle screws in the mid-upper thoracic vertebrae in clinics.
  
  
  
  151 consecutive patients underwent thoracic instrumentation and fusion for a total of 582 pedicle screws placed in the mid-upper thoracic vertebrae. Using computer software, the authors constructed drill templates that fit onto the posterior elements of the mid-upper thoracic vertebrae with drill guides designed to instrument the pedicles. The start point and three dimensional location of the planned and inserted screws were measured and compared.
  
  
  
  Grading of the CT scans revealed 559 (96.1 %) out of 582 screws completely within the desired pedicle. The direction of pedicle violation included 5 medial, 2 airball, and 16 lateral. The paired t test suggested that these results were statistically significant in more than half of the locations (T1-left-TA(P = 0.024), T2-left-SA(P = 0.031), T3-left-SA(P = 0.014), T4-left-TA(P = 0.004), T5-left-TA(P = 0.034), T7-left-TA(P = 0.000). T1-right-TA(P = 0.049), T2-right-TA(P = 0.044), T3-right-TA(P = 0.014), T5-right-TA(P = 0.013)). The paired t-test suggested that these results were statistically significant at several locations (T4-left-Δy(P = 0.041), T5-left-Δx(P = 0.016), T3-right-Δy(P = 0.015)).
  
  
  
  Use of a rapid prototyping drill template to assist in the placement of mid and upper thoracic pedicle screws may lead to increased accuracy. This patient specific technology must be combined with an understanding of the patients' anatomy and carefully secured to the posterior elements intraoperatively to avoid nerve or vascular complications.
authors.affiliation: Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, 315040, Zhejiang Province, China. huyong610@163.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, 315040, Zhejiang Province, China.
authors.forename: Zhen-Shan
authors.initials: ZS
authors.lastname: Yuan
authors.affiliation: Department of Orthopaedic Surgery, University of Utah, Salt Lake City, UT, USA.
authors.forename: William Ryan
authors.initials: WR
authors.lastname: Spiker
authors.affiliation: Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, 315040, Zhejiang Province, China.
authors.forename: Wei-Xin
authors.initials: WX
authors.lastname: Dong
authors.affiliation: Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, 315040, Zhejiang Province, China.
authors.forename: Xiao-Yang
authors.initials: XY
authors.lastname: Sun
authors.affiliation: Institute of Biomedical Manufacturing and Life Quality Engineering, School of Mechanical and Power Energy Engineering, Shanghai Jiaotong University, Shanghai, 200240, China.
authors.forename: Jian-Bing
authors.initials: JB
authors.lastname: Yuan
authors.affiliation: Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, 315040, Zhejiang Province, China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Spinal Surgery, Ningbo No.6 Hospital, Ningbo, 315040, Zhejiang Province, China.
authors.forename: Bingke
authors.initials: B
authors.lastname: Zhu
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods / Q000706:statistics & numerical data; D065289:Pedicle Screws; D025321:Surgery, Computer-Assisted / Q000379:methods / Q000706:statistics & numerical data; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D014057:Tomography, X-Ray Computed
keywords: Pedicle screw; Personalized drill template; Post–pre registration; Rapid prototyping; Thoracic