The Morphology of Degenerated Lumbar Disc May Indicate Segmental Instability: Technical Note

Lumbar intervertebral disc degeneration is related to progressive alterations in the disc tissue composition and morphology, such as disc dehydration, decreased disc height, osteophyte formation and endplate calcification. These changes are related to aging and usually precede facet joint osteoarthritis. The grade of disc degeneration is related to segmental instability. The morphology of lumbar intervertebral disc degeneration may be potential cause for instability. This work aimed to describe the potential instability associated with the conical degenerated lumbar disc which is wide anteriorly-and narrow posteriorly in comparison to adjacent disc level. Radiological studies and intraoperative notice include, degenerative spondylolithesis, fracture pars, spondylolithsis, facet opening with abnormal ballooned and lose facet joint capsule, and loose lamina. This technical note highlights the importance of morphology of the degenerated lumbar disc which assume conical shape on Sagittal MRI which may indicate instability and required careful investigation before surgery