Low back pain is one of the most common reasons that patients seek medical attention. Spinal stenosis is one of the main causes of low back pain, but the symptoms and signs are often bizarre and vague, and delay the diagnosis. Therefore it is necessary to standardize the diagnosis of spinal stenosis objectively.

We studied 38 patients assessed spinal stenosis clinically, which diagnosis were established by CT or/and MRI. The results were compared with each other.

The major results were as follows:

1) Clinically, the most common symptom was radicular pain, and then lumbago, pseudoclaudication, and neurologic symptoms and signs.

2) Radiologically, the most common type of lumbar stenosis was central type, and totally, the most common involved level is L4-5 level, and central stenosis was more common in L3-4 level, lateral stenosis common in L5-S1 level.

3) Electrodiagnostically, somatosensory evoked potential abnormalities were found more than abnormalities of needle EMG and combined type.

We conclude that the abnormal findings of electrodiagnostic diagnosis were more common in lateral type than in central type, and the abnormal spontaneous activities found more in lateral than in central. So, the involved nerve roots and neuromuscular structures seem more severely injured in lateral stenosis than central stenosis.