Intradiscal glycerol or bupivacaine in the treatment of low back pain.

A total of 15 patients suffering from chronic low back pain were treated with an intradiscal injection of either 1 ml of 50% glycerol or 2 ml of 0.5% bupivacaine. Most (60%) of the patients had previously undergone spinal surgery for lumbar disc herniation or spinal stenosis and 73% showed clinical signs and symptoms of segmental instability of the lumbar spine. According to self-evaluation questionnaires, immediate response to both treatments was mainly good. Of the 9 patients who received glycerol, 56% showed subjective improvement on the first day after the injection and after two weeks, 45% of the patients still felt improvement. After one month, however, the pain had reappeared in all except one (11%) patient. The corresponding numbers for the 6 with bupivacaine treated patients were 83%, 67%, and 17%. Based on the very short duration of response to the treatment, we did not find intradiscal injections with these agents to be cost-effective. In our department, this therapeutic approach is no longer employed in patients with chronic discogenic pain.