DOS 2018

DOS Kongressen 2018 · 191 Spinopelvic Parameters depending on the Angulation of the Sacral Endplate are less Reproducible than other Spinopelvic Parameters in Adult Spinal Deformity Patients. Tanvir Johanning Bari, Dennis Winge Hallager, Niklas Tøndevold, Ture Karbo, Lars Valentin Hansen, Benny Dahl, Martin Gehrchen Spine Unit, Department of Orthopedic Surgery, Rigshospitalet, Copenhagen University Hospital; Department of Orthopedics and Scoliosis Surgery, Texas Children’s Hospital and Baylor College of Medicine Background: Spinopelvic parameters and Sagittal Vertical Axis (SVA) are com- monly used sagittal plane parameters for preoperative planning and postop- erative evaluation of patients with Adult Spinal Deformity (ASD). Previous re- producibility studies have focused on describing the reliability using Intraclass Correlation Coefficients (ICC) thus quantifying the methods´ ability to distin- guish between individuals. To our knowledge, no previous study in patients with ASD has reported the measurement error in terms of limits of agreement. Purpose / Aim of Study: The current study aimed to report the agreement and reliability for measurements of Pelvic Incidence (PI), Pelvic Tilt (PT), Sacral Slope (SS) and SVA in ASD patients. Materials and Methods: In a consecutive, one-center cohort of 64 patients referred for ASD evaluation, a blinded test-re-test study was performed. Reliability was assessed using ICC while 95% Limits of Agreement (LOA) were used to quantify agreement. Findings / Results: We found “excellent” (ICC>0.9) results in all analyses of reliability except for inter-rater PI which was classified as “good” (ICC = 0.89). However, considerable inter-rater measurement error was observed for param- eters depending on the angulation of the sacral endplate (95%LOA of ±11° and ±14° for SS and PI respectively) compared to ±5° for PT and ±7mm for SVA which depends on the location of the sacral endplate. Intra-rater agreement was only slightly better. Conclusions: These are to our knowledge the first estimates of measurement error for sagittal spinopelvic parameters in ASD patients. Despite near excellent ICCs, we found considerable measurement error for parameters depending on the angulation rather than the location of the sacral endplate. 132.