title: Analysis of measurement accuracy for craniovertebral junction pathology : most reliable method for cephalometric analysis.
abstract: OBJECTIVE
  This study was designed to determine the most reliable cephalometric measurement technique in the normal population and patients with basilar invagination (BI).
  
  
  METHODS
  Twenty-two lateral radiographs of BI patients and 25 lateral cervical radiographs of the age, sex-matched normal population were selected and measured on two separate occasions by three spine surgeons using six different measurements. Statistical analysis including intraclass correlation coefficient (ICC) was carried out using the SPSS software (V. 12.0).
  
  
  RESULTS
  Redlund-Johnell and Modified (M)-Ranawat had a highest ICC score in both the normal and BI groups in the inter-observer study. The M-Ranawat method (0.83) had a highest ICC score in the normal group, and the Redlund-Johenll method (0.80) had a highest ICC score in the BI group in the intra-observer test. The McGregor line had a lowest ICC score and a poor ICC grade in both groups in the intra-observer study. Generally, the measurement method using the odontoid process did not produce consistent results due to inter and intra-observer differences in determining the position of the odontoid tip. Opisthion and caudal point of the occipital midline curve are somewhat ambiguous landmarks, which induce variable ICC scores.
  
  
  CONCLUSIONS
  On the contrary to other studies, Ranawat method had a lower ICC score in the inter-observer study. C2 end-plate and C1 arch can be the most reliable anatomical landmarks.
authors.affiliation: Department of Neurosurgery, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea.
authors.forename: Ho Jin
authors.initials: HJ
authors.lastname: Lee
authors.forename: Jae Taek
authors.initials: JT
authors.lastname: Hong
authors.forename: Il Sup
authors.initials: IS
authors.lastname: Kim
authors.forename: Jae Yeol
authors.initials: JY
authors.lastname: Kwon
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Lee
keywords: Basilar invagination; C1 arch; C2 end plate; Cephalometric measurement; Odontoid process; Opisthion