Geometrical dimensions and morphological study of the lumbar spinal canal in the normal Egyptian population

Information regarding the precise dimensions of the lumbar vertebrae is essential for spinal surgery and instrumentation. When stenosis of the vertebral canal or the intervertebral foramen exists, the neural structures in them can be affected and cause symptoms such as low back or radicular pain. Accurate and comprehensive spinal canal measurements in the lumbar vertebrae are incomplete. The purpose of this study was to collect data on the dimensions of the lumbar spinal canal from computed tomography scans. Three hundred patients (162 men and 138 women) were studied. Computed tomography scans were obtained to determine the normal values of the midsagittal diameter, interpedicular distance, and lateral recess depth in the normal Egyptian population. The narrowest level was L3. The range of the midsagittal diameter was 11.07 to 26.07 mm at all levels. The range of the interpedicular distance was 17.00 to 43.41 mm at all levels. In all patients at all levels, mean lateral recess depth was 6.7 mm (range, 4-14 mm). The narrowest lateral recess depth was at L5. Few patients (3.3%) had a statistically stenotic midsagittal diameter measurement. The canal shape was not uniform along the 5 lumbar vertebrae; it ranged from being circular or rounded in the upper lumbar vertebrae to triangular in the midlumbar vertebrae to trefoil in the lower lumbar vertebrae, especially at L5. Trefoil canals existed mainly in the lower lumbar vertebrae at L5, followed by L4. Data from computed tomography scans combined with accurate measurements are the basis for anatomical studies, clinical research, and the development of implants suitable for a group of patients with measurements different from the population standard.