Spinal nerve block. A diagnostic test in sciatica

The cause of sciatica has been studied by blocking spinal nerves of the lumbosacral plexus in intervertebral foramina. The nerve, which is singled out with the aid of an image intensifier, is injected with 1 ml of 1 per cent Xylocain. If the Xylocain injection eliminates the sciatic pain, the surgeon may be confident that a true nerve-root compression is involved, and he can then explore as far as he finds necessary. The correlation between the site of compression and the level indicated by the test was confirmed by operation in 19 patients.