Study Design
Radiographic measurement of the lumbar disc height
Objectives
To measure the lumbar disc height on the radiographs in normal Koreans.
Summary of Literature Review:
Many reports show good results after many procedures, such as inter-vertebral body fusion using a cage or total disc replacement, which restores the adequate disc height. However, there are no references regarding the range of normal lumbar disc heights in Korean adults, which can be used as a standard for the implant size.
Materials and Methods
One hundred and thirty two subjects (age range 20 to 40 years), who had no previous history of low back pain and no significant findings on the physical examination, were enrolled in this study. The plain lateral lumbar spine radiograph was taken in the supine position. The intervertebral disc heights were measured at the anterior, middle and posterior portion of each lumbar disc. The average magnification rate was 115%, and the disc heights were corrected by the magnification rate in each segment.
Results
The lumbar disc height showed a cranio-caudal pattern in both the male and female groups. The L4-5 disc heights were highest at the anterior, middle and posterior portion in males. The L4-5 disc heights were highest at the middle and posterior portion in females. The L5-S1 disc height was highest at the anterior portion in females, but there was no significant difference between the L4-5 and L5-S1 disc height at the anterior portion. There was no significant difference in disc height between males and females except at the anterior portion of the L1-2 and L2-3 disc. There was no significant decrease in disc height in overweight people at all measured site in males and females except at the posterior portion of the L1-2 disc in males.
Conclusion
This study is meaningful in that it provides a reference value for the lumbar disc height in Korean adults. The measured values might also be useful for manufacturing a Korean model of an artificial lumbar disc prosthesis or surgical instruments for lumbar interbody fusion.