title: The Scaphoid Safe Zone: A Radiographic Simulation Study to Prevent Cortical Perforation Arising from Different Views.
abstract: OBJECTIVE
  The purpose of this study was to simulate and calculate the probability of iatrogenic perforation of the scaphoid cortical bone when internal fixation appeared to be safe on radiographs. The results will assist surgeons in determining proper screw placement.
  
  
  METHODS
  Thirty scaphoids were reconstructed using computed tomography data and image-processing software. Different central axes were determined by the software to simulate the surgical views. The safe zone (SZ) and risk zone (RZ) were identified on the axial projection radiographs by comparing the scaphoid bone stenosis measured by the fluoroscopic radiographs with a three-dimensional reconstruction of the scaphoid stenosis. Each original axial projection radiograph was zoomed and compiled to match a calculated average image. The RZ, SZ, and probability of perforations in various quadrants were calculated.
  
  
  RESULTS
  Using a volar view (approach), the mean risks of cortical perforation were 25% with screws and 36% with k-wires. Using a dorsal view (approach), the mean risks of cortical perforation were 18% with screws and 30% with k-wires. A high risk of perforation was detected at the ulnar-dorsal zone.
  
  
  CONCLUSIONS
  Surgeons should be wary of screws that appear to lie close to the scaphoid cortex on both anteroposterior (AP) and lateral radiographs, particularly in the ulnar-dorsal and radial-dorsal quadrants, because such screws are likely to perforate the cortex. The position of the internal fixator should be assessed using a diagram outlining the various SZs. Therapeutic, Level III.
authors.affiliation: Department of Orthopedic Surgery, Key Laboratory of Musculoskeletal Trauma &War Injuries PLA, Beijing Key Lab of Regenerative Medicine in Orthopedics, Chinese PLA General Hospital, Beijing, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Quan
authors.affiliation: Department of Orthopedic Surgery, First Affiliated Hospital of PLA General Hospital, Beijing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Hong
authors.affiliation: Department of Orthopedic Surgery, Key Laboratory of Musculoskeletal Trauma &War Injuries PLA, Beijing Key Lab of Regenerative Medicine in Orthopedics, Chinese PLA General Hospital, Beijing, China.
authors.forename: Biao
authors.initials: B
authors.lastname: Chang
authors.affiliation: Department of Orthopedic Surgery, Key Laboratory of Musculoskeletal Trauma &War Injuries PLA, Beijing Key Lab of Regenerative Medicine in Orthopedics, Chinese PLA General Hospital, Beijing, China.
authors.forename: Ruoxi
authors.initials: R
authors.lastname: Liu
authors.affiliation: School of the Biomedical of Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong (HKU), Hong Kong, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of Orthopedic Surgery, Key Laboratory of Musculoskeletal Trauma &War Injuries PLA, Beijing Key Lab of Regenerative Medicine in Orthopedics, Chinese PLA General Hospital, Beijing, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Peng
authors.affiliation: Department of Orthopedic Surgery, First Affiliated Hospital of PLA General Hospital, Beijing, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Department of Orthopedic Surgery, Key Laboratory of Musculoskeletal Trauma &War Injuries PLA, Beijing Key Lab of Regenerative Medicine in Orthopedics, Chinese PLA General Hospital, Beijing, China.
authors.forename: Shibi
authors.initials: S
authors.lastname: Lu
mesh_terms: D000328:Adult; D001863:Bone Screws; D005260:Female; D005593:Fracture Fixation, Internal / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D021361:Scaphoid Bone / Q000000981:diagnostic imaging*; D055815:Young Adult