The results of postoperative epidural administration of saline solution
(a placebo), morphine, methylprednisolone, and a combination of morphine
and methylprednisolone for the reduction of pain after an operation for
spinal stenosis or a herniated intervertebral disc were compared in a
prospective, randomized blinded study. Epidural administration of morphine
and methylprednisolone--either alone or in combination--significantly
reduced the need for analgesia after an operation for spinal stenosis (p
< 0.05) but not after an operation for a herniated intervertebral disc.
Morphine and methylprednisolone did not have an addictive effect on the
reduction of pain. Itching was significantly more common in the patients
who had received morphine than in those who had received the placebo (p =
0.04). Although urinary retention was more frequent after the use of
morphine than after the use of the placebo, the difference was not
significant with the size of the sample that was analyzed (p = 0.25).