Diagnosis and decision making in lumbar disc prolapse and nerve entrapment.

This prospective study of 185 patients undergoing first-time lumbar surgery compared how accurately clinical criteria and water-soluble myelography predicted the operative findings. Clinical diagnostic criteria of nerve root pain, root irritation signs, and neurologic signs of root compression supplemented by myelography were shown to be much more accurate than myelography alone, both in predicting the presence or absence of nerve root involvement and in distinguishing disc prolapse from bony entrapment. Provided the clinical criteria were clearly defined, patients with three or more of the four criteria were usually found to have a disc prolapse while bony entrapment could frequently be identified with one or two criteria. It is concluded that although lumbar disc prolapse is well-recognized, in practice clinical assessment and diagnostic criteria need to be defined more clearly to match increasingly sophisticated radiology.