Morphometric Study of the Pedicles of Thoracic and Lumbar Vertebrae in Korean

Kim, Nam Hyun; Lee, Hwan Mo; Kim, Ho Jeong; Chung, In Hyuk; Kim, Sang Jin

Abstract

Total 7,446 pedicle measurements were made from T1 to L6. Direct dimensional measurements were obtained from dried adult human spinal columns. Parsmeters considered were the pedicle isthmus diameter in the coronal and sagittal planes, pedicle angles in the transverse and sagittal planes, and the depth to the anterior cortex in a line parallel to the midline of the vertetral body and along the pedicle axis. The results were as follows. 1. The widest pedicle transverse diameters were seen at L6, the narrowest at T4. 2. The widest pedicle superoinferior diameters were seen at T12, the narrowes at T1. 3. In the transverse plane, the posterolateral to anteromedial pedicle axis orientations were seen at all levels except at T12 and T12. 4. In the sagittal plane, the pedicles angled caudally at L5 and cephaladly from L3 to T1. 5. In the thoracolumbar junction, the percentage less than 6mm in the transverse diameters of pedicles is most high at L1(27%) and followed by at the level L2, T11 and T12. 6. The use of 6mm transpedicular screws can be expected to violate the cortex of the pedicles in a significant number in the upper lumbar spine. 7. The 5mm transpedicular screws can be used safely below the T11 level. 8. It is advisable to use roentgen image intensifier during insertion of the transpedicular screws.