Effect of Trunk Position on Spinal Topography Measurements Using Newly Developed System
Leah Rankine, Xue C. Liu, Channing Tassone, Sergey Tarima, John Thometz, Roger Lyon
Abstract
Introduction: A variety of noninvasive methods of curve analysis, such as Moir photography, Integrated Shape Imaging System (ISIS), and the Quantec Spinal Imaging System (QSIS), were developed. Based upon our experience with the use of QSIS for more than 12 years in clinics, recently we have developed a new userfriendly raster stereography system (Milwaukee Spinal System, MSS).
Objectives: The goal of the current study is to evaluate variability of this system with respect to trunk position.
Materials and Methods: A dummy cast was created using a plastic model of one patient with adolescent idiopathic scoliosis. Optical color-coded markers were placed on each of the cast's spinous process landmarks from T1 to L5 and at each PSIS. Two investigators completed a series of three MSS scans of the dummy cast in each of four different positions: flexed 10° to 20° in the sagittal and transversal plane, and shaking (SH) for a total of 24 scans. After scanning, 13 metrics were extrapolated from the MSS 3D data.
Results: All measurements of intra-rater and inter-observer reliability were goodexcellent (0.8-1.0) with the exception of Pelvic Tilt (inter-rater reliability=0.6). No significant variability was observed for the majority of tested metrics but for spinal deviation from midline (p<0.01).
Conclusion and Significance: Trunk position does result in variability in MSS measurements but only in extreme positions. The MSS is a reliable and reproducible method of raster stereography to monitor the progression of the spinal curvature.