title: A study of sacral anthropometry to determine S1 screw placement for spinal lumbosacral fixation in the Korean population.
abstract: OBJECTIVE
  1. To investigate the incidence of closed-type PSIS in the Korean population. 2. To categorize the morphological features of Korean sacrum. 3. To measure the safe marginal length and angle for screw fixation considering the PSIS and course of the external iliac vein, using a Korean sacrum model.
  
  
  METHODS
  We performed our study in 160 sacra including the pelvic ring obtained from 80 Korean cadavers. The bony measurements were obtained by performing 1-mm computed tomography cuts from the L5 lumbar vertebra to the pelvic ring and excluding other structures. We evaluated the incidence of anatomic variation of the PSIS and measured the safe marginal length and angle for screw fixation considering the PSIS and course of the external iliac vein, using a Korean sacrum model.
  
  
  RESULTS
  Our study showed that the closed type of PSIS is more frequent in males than in females. The optimal angle for screw fixation is 16.91 ± 6.85 (°), while the left side S1 pedicle insertion angle is 16.00 ± 6.20 (°). The average Korean optimal screw length is 58.35 ± 14.90 (cm) for the right side and 55.89 ± 16.16 (cm) for the left side.
  
  
  CONCLUSIONS
  With reference to these parameters, the optimal screw length and angle can be chosen and bicortical anteromedial screw fixation can be easily and safely performed.
authors.affiliation: Department of Orthopaedic Surgery, College of Medicine, Daejeon St. Mary's Hospital, The Catholic University of Korea, Daejeon, Korea.
authors.forename: Young-Yul
authors.initials: YY
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Kee-Yong
authors.initials: KY
authors.lastname: Ha
authors.affiliation: Department of Orthopaedic Surgery, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
authors.forename: Sang-Il
authors.initials: SI
authors.lastname: Kim
authors.affiliation: Department of Orthopaedic Surgery, College of Medicine, Incheon St. Mary's Hospital, The Catholic University of Korea, Incheon, Korea. insoooh@catholic.ac.kr.
authors.forename: In-Soo
authors.initials: IS
authors.lastname: Oh
mesh_terms: D000328:Adult; D000886:Anthropometry; D001863:Bone Screws; D002102:Cadaver; D005260:Female; D005592:Fracture Fixation / Q000379:methods*; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008161:Lumbosacral Region / Q000601:surgery; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D056910:Republic of Korea; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery*; D012737:Sex Factors; D016103:Spinal Fractures / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Anthropometry; Korean population; PSIS; Sacrum; Screw