Intrathecal morphine during lumbar spine operation for postoperative pain control

The analgesic requirements and bladder function of 5 patients who received 1 mg of intrathecal morphine during lumbar spine operation are compared to those of 10 control patients. No analgesics were used by the treatment group for the first 24 hours postoperatively. The test group subsequently required twice the amount of analgesics during the 2nd through 5th days after operation compared to controls. All 5 patients who received intrathecal morphine developed urinary retention for 24 to 36 hours. The brief duration of analgesia, the increased narcotic use after the effects of the morphine dissipated, and urinary retention after a single intraoperative dose of intrathecal morphine suggest caution in using this technique.