THE LOCATION OF THE INTERVERTEBRAL LUMBAR DISC ON THE POSTERIOR ASPECT OF THE SPINE

BACKGROUND Epidural fibrosis or scar formation is considered one cause of failed lumbar discectomy. Avoidance of unnecessary bony resection of the lamina may prevent or decrease postoperative scar formation. Th e knowledge of the precise location of the projection of the lumbar di sc may also facilitate surgery and decrease patient morbidity. No stud ies exist regarding the projection of the lumbar disc on the posterior aspect of the lumbar spine, METHODS Thirty-six whole lumbar spine spe cimens from L1 to L5 (180 lumbar vertebrae) and sacra were used for th is study. Anatomic evaluation included the distance between the superi or border of the vertebral body (inferior border of the intervertebral disc) and the superiormost margin of the lumbar lamina, and the dista nce between the inferior border of the vertebral body (superior border of the intervertebral disc) and the inferiormost margin of the lumbar lamina, The width of the interlaminar space was also measured. RESULT S The data showed that the level of the superior margin of the lamina was consistently inferior to the superior border of the corresponding vertebral body from L1 to S1. This distance for both sexes ranged from 10 to 11 mm for L1-L5 and 14 mm for S1. The level of the inferior mar gin of the lamina varied from 3 mm inferior to 9 mm superior to the in ferior border of the corresponding vertebral body for L1-L5. The width of the interlaminar space averaged from 16.8 mm for L1 to 31.0 mm for L5, CONCLUSIONS This study suggests that the superior margin of the l amina represents a consistent, useful landmark in determining the loca tion of the lumbar disc on the posterior aspect of the spine, The rela tionship between the inferior margins of the lamina and the vertebral body is not consistent. (C) 1997 by Elsevier Science Inc.