Diagnostic Studies to Evaluate Lumbar Spinal Stenosis

Richard G. Fessler, MD, PhD

Professor of Neurological Surgery

Northwestern University

Kristine M. Khoo, NP

Acute Care Nurse Practitioner

Chicago Institute of Neurosurgery and Neuroresearch

Larry T. Khoo, MD

Neurosurgeon

The Spine Clinic of Los Angeles

Diagnostic studies are usually performed if symptoms do not subside after a period of 3 to 6 months of therapy such as rest, anti-inflammatory medications, and physical therapy. X-rays are ordered cautiously because many people who do not have any symptoms of spinal stenosis have abnormal x-rays, CT scans, and MRI's. Surgery should only be performed in patients whose symptoms correlate with findings on these studies and a history that supports these findings.

Typically, plain x-rays are done first. They are helpful in looking for infection, tumors, and identifying problems with alignment of the spine (Figure 4a).

Figure 4a

But X-rays will not always identify lumbar spinal stenosis. CT scans have become the most widely used test for evaluating the spine because it is noninvasive and provides three-dimensional views of the spine. It is also particularly helpful in differentiating between hard tissue (bony osteophytes) and soft tissue (intervertebral discs). Myelography involves injection of dye into the spinal sac where is mixes with the cerebrospinal fluid. Any outward protrusion will block the flow of the dye. CT scans done in conjunction with myelography are particularly helpful diagnosing lumbar spinal stenosis (Figure 4b).

Figure 4b

The MRI is the newest non-invasive diagnostic test for evaluating the spine and offers more precise description of disc disease, soft tissue changes and the degree of stenosis (Figure 4c).

Figure 4c