title: Rapid prototyping drill guide template for lumbar pedicle screw placement.
abstract: OBJECTIVE
  To develop a novel method of spinal pedical stereotaxy by reverse engineering and rapid prototyping techniques, and to validate its accuracy by experimental and clinical studies.
  
  
  METHODS
  A 3D reconstruction model for the desired lumbar vertebra was generated by using the Mimics 10.11 software, and the optimal screw size and orientation were determined using the reverse engineering software. Afterwards, a drill template was created by reverse engineering principle, whose surface was the antitemplate of the vertebral surface. The drill template and its corresponding vertebra were manufactured using the rapid prototyping technique.
  
  
  RESULTS
  The accuracy of the drill template was confirmed by drilling screw trajectory into the vertebral biomodel preoperatively. This method also showed its ability to customize the placement and size of each screw based on the unique morphology of the lumbar vertebra.The drill template fits the postural surface of the vertebra very well in the cadaver experiment. Postoperative CT scans for controlling the pedicle bore showed that the personalized template had a high precision in cadaver experiment and clinical application. No misplacement occurred by using the personalized template. During surgery, no additional computer assistance was needed.
  
  
  CONCLUSIONS
  The authors have developed a novel drill template for lumbar pedicle screw placement with good applicability and high accuracy. The potential use of drill templates to place lumbar pedicle screws is promising. Our methodology appears to provide an accurate technique and trajectory for pedicle screw placement in the lumbar spine.
authors.affiliation: Department of Orthopedics, Kunming General Hospital, Chengdu Military command of PLA, Kunming 650032, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Lu
authors.forename: Yong-Qing
authors.initials: YQ
authors.lastname: Xu
authors.forename: Yuan-Zhi
authors.initials: YZ
authors.lastname: Zhang
authors.forename: Yan-Bing
authors.initials: YB
authors.lastname: Li
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Shi
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Chen
authors.forename: Yu-Bing
authors.initials: YB
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D001863:Bone Screws; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000295:instrumentation*; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed