Forty-two consecutive patients with suspected lumbar disc protrusions were studied prospectively to compare the diagnostic accuracy of low-field strength MRI with that of radiculography. Thirty patients subsequently underwent surgical exploration at 33 levels and the operative findings were compared to both methods of diagnostic imaging. All patients had MRI studies, whilst 29 patients also had radiculography. Both studies were evaluated without prior knowledge of the clinical signs, operative findings or the results of other imaging techniques. MRI predicted the correct diagnosis in 29 of the 33 levels explored, an accuracy of 88%. All discs proven to be abnormal demonstrated a reduced signal from the nucleus pulposus. There were two false positive results and two doubtful cases but no false negatives. Radiculography predicted the correct diagnosis in 24 of 32 levels explored, an accuracy of 75%. There were two false positive results, five doubtfuls and one false negative. The overall accuracy when both tests were considered rose to 94%. Of the remaining 12 patients all except one showed good correlation between the MRI and radiculographic findings. These results indicate that low field strength MRI is slightly better than radiculography in diagnosing lumbar disc protrusions

The technique and results of microsurgical techniques for lumbar disc protrusions in 60 patients are presented. All patients were followed up for a minimum of 2.5 years, and 91% had good or excellent results. The only patient with a recurrent disc sequestration had a good result after a second operation

Infection of the intervertebral space is a rare complication of operation on the disc (Ford and Key 1955). It occurred in five cases in a series of 650 operations for lumbar disc protrusion done by two of the authors of this paper--an incidence of 0-8%. Symptoms began between seven and twelve days after operation. After initial relief of the original sciatic pain, the patients developed severe back pain and muscle cramps in the legs. Straight-leg raising became much more limited than before operation. The erythrocyte sedimentation rate was raised in all cases. The diagnosis was confirmed by rescreening the Myodil, when an indentation was seen opposite the intervertebral space from which the disc had been excised. Early removal of infected material from the disc space resulted in complete relief of pain and cure of the infection

1. Passive straight-leg raising may induce pain in the back or leg or a combination of both in patients with acute lower lumbar disc lesions. Clinical, myelographic and operative observations were carried out prospectively in fifty such cases to investigate the relation of the pattern of pain on straight-leg raising to the site of the protrusion.

2. In patients with central protrusion straight-leg raising induced mainly back pain. In patients with intermediate protrusion, lying in contact with both dura and nerve root, a combination of back and leg pain predominated. Patients with lateral protrusion usually experienced only pain in the leg. This correlation was found in 80 per cent of cases.

3. Production of pain in the leg by straight-leg raising is of practical significance in lateral protrusions where myelography may be normal.

4. Pain in the back and pain in the leg on straight-leg raising may be related respectively to dural and nerve root sensitivity.

1. Four cases of abnormal arrangement of the lower lumbar and sacral nerves within the spinal canal are reported. 2. In all four cases the presentation was like that associated with acute lumbar disc protrusion, though in only two cases was a protrusion found at operation. 3. The significance of the findings is discussed and the findings are compared with those in the eighteen other recorded cases