title: Evaluation of a Novel Method for Determining Transverse Plane Pelvic Obliquity.
abstract: METHODS
  This was a retrospective review of neuromuscular scoliosis radiographs evaluating interobserver and intra-observer error for a novel method of transverse plane pelvic obliquity.
  
  
  OBJECTIVE
  To evaluate the utility of a previously described method by Lucas et al. of determining transverse plane pelvic obliquity using standard radiographs in patients with cerebral palsy and neuromuscular scoliosis.
  
  
  BACKGROUND
  Evaluation of pelvic obliquity in the transverse plane has not been thoroughly studied. The pelvis has been noted to function as intercalary vertebra in neuromuscular scoliosis, resulting in marked obliquity in all 3 planes.
  
  
  METHODS
  Forty radiographs were chosen from 10 patients with cerebral palsy and neuromuscular scoliosis who had had a posterior spine arthrodesis and Galveston spino-pelvic fixation. Four observers independently examined the radiographs at different levels of training on 2 dates 1 week apart. Measurements recorded by each observer were described by Lucas et al.: E (the distance measured on lateral radiographs between the ilium at the inferior part of the sacro-iliac joint and the lateral edge of the anterior superior iliac spine), FRand FL(the coronal plane linear distance between the same 2 landmarks, measured from a posteroanterior radiograph, where F was measured for both the left (FL) and right (FR) sides of the pelvis, respectively), and β (the transverse plane rotation of the pelvis). Reproducibility of the measurements were analyzed using the concordance correlation coefficient (CCC). A CCC of 0.80 or higher was considered excellent agreement.
  
  
  RESULTS
  The CCC between the first and second sets of measurements was lowest for E and highest for the calculated β, although none of the CCC calculations was statistically significant, demonstrating poor agreement.
  
  
  CONCLUSIONS
  The ability to reliably measure and calculate the degree of transverse plane rotation by radiographs in cerebral palsy patients with spino-pelvic deformity by the method described by Lucas et al. is poor, likely because of difficulty in consistently identify pelvic landmarks.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Pennsylvania State University College of Medicine, Penn State Hershey Medical Center, Hershey, PA 17033, USA.
authors.forename: Joel A
authors.initials: JA
authors.lastname: Torretti
authors.affiliation: Division of Pediatric Orthopaedics, Phoenix Children's Hospital, Phoenix, AZ 85016, USA. Electronic address: lsegal@phoenixchildrens.com.
authors.forename: Lee S
authors.initials: LS
authors.lastname: Segal
authors.affiliation: Department of Orthopaedics and Rehabilitation, Pennsylvania State University College of Medicine, Penn State Hershey Medical Center, Hershey, PA 17033, USA.
authors.forename: Rodney E
authors.initials: RE
authors.lastname: Brenneman
authors.affiliation: Division of Pediatric Orthopaedics, Phoenix Children's Hospital, Phoenix, AZ 85016, USA.
authors.forename: M Wade
authors.initials: MW
authors.lastname: Shrader
authors.affiliation: Department of Orthopaedics and Rehabilitation, Pennsylvania State University College of Medicine, Penn State Hershey Medical Center, Hershey, PA 17033, USA.
authors.forename: Vernon M
authors.initials: VM
authors.lastname: Chinchilli
authors.affiliation: Carolinas Medical Center, 1025 Morehead Medical Dr #300, Charlotte, NC 28204, USA.
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Vanderhave
keywords: Pelvic obliquity; Radiographs; Scoliosis