title: Reliability Analysis of Spino-Pelvic Parameters in Adult Spinal Deformity: A Comparison of Whole Spine and Pelvic Radiographs.
abstract: METHODS
  Retrospective study.
  
  
  OBJECTIVE
  To examine the reliabilities of sagittal spino-pelvic alignment measurements using whole spine-pelvic and local pelvic radiographs and to determine whether spinal deformity affects these reliabilities.
  
  
  BACKGROUND
  Sagittal spino-pelvic alignment is important in adult spinal deformity patients (ASD). Spino-pelvic parameters are closely related to health-related quality of life and indispensable for surgical planning. However, few studies have focused on the reliability of these measurements.
  
  
  METHODS
  Three spino-pelvic parameters, pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) were measured in 2 patient groups: 33 adult scoliosis (AS) and 33 nondeformity (ND) patients, using whole spine-pelvic lateral radiographs (whole spine radiographs) and local pelvic lateral radiographs (local pelvic radiographs), by 5 experienced spine surgeons. Intra- and interobserver reliabilities for each procedure were evaluated by intraclass correlation coefficients (ICC). The interobserver reliability differences between the 2 procedures were statistically evaluated. The difference between the largest and smallest measurements among the 5 observers was also evaluated in the AS and ND groups.
  
  
  RESULTS
  Measurement of the 3 parameters using whole spine or local pelvic radiographs showed good to excellent intraobserver reliability (range of ICC: 0.820-0.935). The interobserver reliabilities of PI and PT from local pelvic radiographs were significantly higher than those from whole spine radiographs (P < 0.002). The intraobserver reliabilities of PI and PT from pelvic radiographs tended to be higher than those from whole spine radiographs, but the differences were not statistically significant. The reliability of SS was comparable between the 2 methods. The differences between the highest and lowest PI and PT measurements were smaller with the pelvic compared to whole spine radiographs. These findings were consistent in the AS and ND groups.
  
  
  CONCLUSIONS
  Local pelvic radiography is more reliable than whole spine radiography for determining spino-pelvic parameters, and we recommend its use for evaluating ASD patients.
  
  
  METHODS
  3.
authors.affiliation: *Department of Orthopedic Surgery, Keio University, Tokyo, Japan†Department of Spine Surgery, Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, China‡Department of Orthopedic Surgery, National Defense Medical College, Saitama, Japan§Department of Advanced Therapy for Spine and Spinal Cord Disorders, Keio University, Tokyo, Japan||Kawasaki Municipal Hospital, Kanagawa Japan¶Saiseikai Central Hospital, Tokyo, Japan#Kitasato Institute Hospital, Tokyo, Japan**Department of Preventive Medicine and Public Health, Center for Clinical Research, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Rui-Qiang
authors.initials: RQ
authors.lastname: Chen
authors.forename: Naobumi
authors.initials: N
authors.lastname: Hosogane
authors.forename: Kota
authors.initials: K
authors.lastname: Watanabe
authors.forename: Haruki
authors.initials: H
authors.lastname: Funao
authors.forename: Eijiro
authors.initials: E
authors.lastname: Okada
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Fujita
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Hikata
authors.forename: Akio
authors.initials: A
authors.lastname: Iwanami
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsuji
authors.forename: Ken
authors.initials: K
authors.lastname: Ishii
authors.forename: Takayuki
authors.initials: T
authors.lastname: Abe
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
authors.forename: Masaya
authors.initials: M
authors.lastname: Nakamura
authors.forename: Morio
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010388:Pelvis / Q000000981:diagnostic imaging*; D011859:Radiography / Q000592:standards; D015203:Reproducibility of Results; D012600:Scoliosis / Q000145:classification* / Q000000981:diagnostic imaging*; D013131:Spine / Q000000981:diagnostic imaging*