The radiological distance between the lumbar pedicle and laminar edges

Lumbar foraminal inner zone herniations are challenging cases, for which there are variety of approaches. However, there is no information about the distance between these herniations and the edges of the respective lamina. The aim of this study was to measure the distance between the inferomedial aspect of lumbar pedicles and laminar edges.

The lumbar CT images of 30 cases were reviewed. The distances between the edges of the lamina and the inferomedial aspects of the respective pedicles were measured. The study was performed on L3, L4, and L5 lumbar vertebrae on both sides.

The mean distance between the upper edge of the lamina and the inferomedial aspect of the respective pedicle was found to be 10.8 ± 3.5, 11.6 ± 2.4, and 14.1 ± 2.3 mm on the left side, and 11.1 ± 4.4, 12.0 ± 2.5, and 13.8 ± 3.2 mm on the right side of L3, L4, and L5 vertebrae. The mean distance between the inferior edge of the lamina and the inferomedial aspect of the respective pedicle was found to be 23.8 ± 4.2, 19.3 ± 3.5, and 11.6 ± 2.9 mm, on the left side, and 23.9 ± 3.2, 19.1 ± 3.7, and 12.4 ± 2.8 mm on the right side of L3, L4, and L5 vertebrae. There was no statistically significant difference between values of the left and right sides (p > 0.05).

This study revealed that distance between the inferomedial aspect of lumbar pedicles and the superior edge of the same lamina was shorter than the distance between the inferomedial aspect of lumbar pedicles and the inferior edge of the same lamina at L3 and L4 level. It was concluded that this shorter distance could be taken into consideration during surgery on inner zone 1 foraminal herniations.