Diagnosis of spinal canal stenosis

The patient’s medical history (anamnesis), with the indications of spinal canal stenosis, points the way forward. Mostly, however, rather the unspecific symptoms of the disease are described. The clinical picture and the level of spinal canal stenosis cannot usually be determined by the examination findings alone.

Imaging techniques help to diagnose the disease and its extent. In principle, x-rays of the spine can be described as basic imaging diagnostics. The X-rays provide the treating physician with an insight into the spinal posture.

In addition, bony changes (calcium salt reduction, spinal curvature, a vertebral fracture, vertebral joint arthrosis, vertebral body attachments) and disc degeneration can be detected. The spinal canal stenosis itself cannot be directly detected in conventional x-rays. This requires cross-sectional imaging techniques such as CT (computed tomography) and MRI (magnetic resonance imaging), which can depict the width of the spinal canal through their transverse incisions.

Cross-sectional imaging (CT and MRI of the lumbar or cervical spine, either with or without contrast agent) allows the pain to be assigned to a specific nerve or spinal segment. With the help of a CT (computed tomography) examination, more detailed questions regarding the bony structure in particular can be answered (e.g. spinal canal stenosis, vertebral body fracture). Even more valuable in spinal diagnostics, however, is the MRI of the lumbar or cervical spine (magnetic resonance imaging), which, in addition to the bony structures, is significantly better than CT, and also shows the soft tissue structures (intervertebral discs, nerve roots, ligaments).

All of the above-mentioned diseases can be detected by MRI of the lumbar or cervical spine and assigned to a specific spinal segment. Myelography describes an examination in which the patient is injected with contrast medium into the dural sac. The dural sac surrounds the spinal cord and, in the lower lumbar spine, is the area surrounding the beginning of a nerve before it leaves the spinal canal.

By mixing nerve fluid and contrast medium, specific questions regarding the spinal cord can be answered. After the contrast medium has been injected, functional images of the spinal column are usually taken (in flexion and extension) to detect nerve/spinal cord compression in a functional position. However, myelography has been superseded by MRI in its predominant position, which is partly due to the fact that the administration of contrast medium carries a certain – albeit low – risk of complications.

However, it offers the advantage that images of the spine can be obtained under stress (i.e. with the patient standing) and in certain body positions. MRI has not been able to do this so far. At the same time, spinal canal stenosis often requires a CT scan, which is more meaningful for certain questions due to the contrast medium applied (myelo-CT) and is even superior to MRI in terms of spinal cord evaluation. In order to exclude nerve damage or to determine the degree of any nerve damage, extended examinations must be performed. This can be done by means of a specialized neurological examination and the determination of neurophysiological parameters (e.g. nerve conduction velocity).