• Amrit S Khalsa, Gregory M Mundis, Mitsuru Yagi, Richard Fessler, Shay Bess, Naobumi Hosogane, Paul Park, Khoi Than, Alan Daniels, Justin Iorio, Justin Ledesma, Stacie Tran, and Robert K Eastlack.
• *San Diego Spine Foundation, San Diego, CA USA †Scripps Clinic, La Jolla, CA USA ‡Keio University, Tokyo, Japan §Rush University, Chicago, IL USA ¶Denver International Spine Center, Denver, CO USA ||National Defense Medical College, Saitama, Japan **University of Michigan, Ann Arbor, MI USA ††Oregon Health & Science University, Portland, OR USA ‡‡Brown University, Providence, RI USA §§Syracuse Orthopaedics, Syracuse, NY USA.
• Spine. 2017 Oct 3.

Study DesignProspectively-collected survey study OBJECTIVE.: To determine the consistency with which spino-pelvic parameters (SPP) are determined in patients with lumbosacral transitional vertebrae (LSTV).Summary Of Background DataThe incidence of LSTV in the general population is as high as 35.6%. The often fixed nature of LSTV relative to the pelvis, but lumbar-type appearance, may lead to differential use of the S1 endplate when performing SPP assessment. This could have significant impact on SPP derived from these landmarks, resulting in considerable variation in surgical planning and decision making.Methods20 patients demonstrating LSTV on standing lateral 36-in spinal radiographs were randomly arranged and independently analyzed by 16 experienced spine surgeons using the same computer software. Pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), and T1 pelvic angle (TPA) were captured. Two weeks after the first assessment, surgeons repeated the measurements after image sequence re-randomization. Intraclass correlation coefficient (ICC) was calculated to evaluate IOR for each SPP. Intra-observer reliability (IAOR) was assessed through an average Pearson's correlation coefficient for each parameter for each surgeon.Results16 surgeons completed initial measurements. IOR was poor for TPA (0.35, 95% CI 0.20, 0.58) and PI (0.42, 95% CI 0.26, 0.65) and fair for LL (0.67, 95% CI 0.51, 0.82) and PT (0.63, 95% CI 0.47, 0.81). 14 surgeons completed phase-2 measurements to assess IAOR. Average parameter PPC showed excellent IAOR (LL 0.86, TPA 0.77, PI 0.78, PT 0.86). Kappa coefficient showed fair agreement for raters choosing the same endplate for measurement (Phase 1 0.38, Phase 2 0.32). By patient, the percentage of raters that chose the S1 endplate for measurement varied from 6.3% to 85.7%.ConclusionsSignificant variability exists when surgeons measure SPP in patients with LSTV. These parameters are critical in determining the goals of surgical reconstruction and such variability may have considerable implications for radiographic goals and outcomes of surgical reconstruction.Level Of Evidence4.

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