Precision measurement of disc height, vertebral height and sagittal plane displacement from lateral radiographic views of the lumbar spine

• Published in: Clinical biomechanics (Bristol) 1997, Vol.12, p.S1-S63
• Main Authors: Frobin, W., Brinckmann, P., Biggemann, M., Tillotson, M., Burton, K.
• Format: Article
• Language: English
• Subjects: Disc injury; lumbar measurement; quantification; radiology; sagittal plane displacement; spinal shape; vertebra
• ISSN: 0268-0033; 1879-1271
• DOI: 10.1016/S0268-0033(96)00067-8

Objective. To compile a database of disc height, vertebral height and sagittal plane displacement from lateral radiographic views of the lumbar spine, valid for male and female subjects in the age range 16–57 years. The protocols used to measure these parameters compensate for distortion in central projection, off-centre position, axial rotation and lateral tilt of the spine as well as for variation in radiographic magnification and stature. Study design. The study comprised designing and testing of measurement protocols, together with subsequent data collection from archive radiographs. Background. Attempts to quantify primary mechanical damage to lumbar vertebrae and discs have been limited due to imprecision when measuring disc height, vertebral height and sagittal plane displacement. Age-related, normative values for these parameters were not previously available. Consequently, important issues like the effectiveness of past and present guidelines for safe manual handling with respect to prevention of overload injuries could not be resolved and judgement on pathological alterations in the morphology of the individual lumbar spine could only be performed in a qualitative, subjective manner. Methods. Based on the analysis of vertebral contours in the lateral radiographic image of the lumbar spine, new protocols for measuring disc height, vertebral height and sagittal plane displacement were developed. The measured data are virtually independent of distortion, axial rotation and lateral tilt. Furthermore, description of height and displacement using dimensionless parameters guarantees independence of radiographic magnification and stature. Subjective influence in the measurement procedure was minimized by automatic computation of contour-landmarks and derived parameters. Measurement errors were assessed from sets of radiographs of spine specimens and serial flexion-extension radiographs; interobserver and intraobserver errors were assessed from repeated measurements of lateral views. For compilation of a database, measurements were performed of a set of 892 lateral views of the lumbar spine of male and female subjects between 16 and 57 years of age. Data from pathologically deformed vertebrae or discs, or from motion segments exhibiting spondylolisthesis or retrolisthesis were excluded by normal radiological inspection; data from spines showing normal, age-related degenerative changes were included. Results. The new protocols allow height and displacement