A New Technique for Digital Fluoroscopic Video Assessment of Sagittal Plane Lumbar Spine Motion

In Brief Study Design. Methodological reliability. Objective. Develop a measurement technique to assess dynamic motion of the lumbar spine using enhanced digital fluoroscopic video (DFV) and a distortion compensated roentgen analysis (DCRA). Summary of Background Data. Controversy over both the definition and consequences of lumbar segmental instability persists. Information from static imaging has had limited success in providing an understanding of this disorder. DFV has the potential to provide further information about lumbar segmental instability; however, the image quality is poor and clinical application is limited. Methods. DFV from 20 male subjects (11 with and nine without low back pain) were obtained during eccentric lumbar flexion (30 Hz). Each DFVs was enhanced with a series of filters to accentuate the vertebral edges. An adapted DCRA algorithm was applied to determine segmental angular and linear displacement. Both intraimage and interimage reliability were assessed using intraclass correlation coefficients (ICC) and standard error of the measurement (SEM). Results. Intraimage reliability yielded an average ICC of 0.986, and the SEM ranged from 0.4–0.7° and 0.2–0.3 mm. Interimage reliability yielded an average ICC of 0.878, and the SEM ranged from 0.7–1.4° and 0.4–0.7 mm. Conclusions. Enhanced DFV combined with a DCRA resulted in reliable assessment of lumbar spine kinematics. The error values associated with this technique were low and were comparable to published error measurements obtained when using a similar algorithm on hand-drawn outlines from static radiographs. A new dynamic radiographic method using a distortion compensated roentgen analysis can be reliably applied to digital fluoroscopic videos (30 Hz) to assess dynamic motion (angular and linear vertebral displacement) of the lumbar spine. This technology has the potential to advance the understanding of lumbar kinematics and segmental instability.