A Prospective Randomized Double-blind Trial of the Use of Intrathecal Fentanyl in Patients Undergoing Lumbar Spinal Surgery

Study Design: A randomized, double-blind controlled study.

Objective: To assess the efficacy and safety of intrathecal fentanyl in the relief of postoperative pain in patients undergoing lumbar spinal surgery.

Summary Of Background Data: Fentanyl has been used as a spinal analgesic in surgery and obstetrics with several studies promoting its efficacy and safety. There is no evidence in the literature about intrathecal fentanyl in lumbar spinal surgery. Previous studies have looked at the use of intrathecal morphine and conclude that it is effective but also associated with respiratory depression.

Methods: Sixty patients undergoing posterior lumbar spine decompression with or without instrumented fusion were randomized to receive either 15 mug of fentanyl intrathecally under direct vision or nothing just before wound closure. After surgery, all patients received intravenous (IV) morphine via patient-controlled analgesia system (PCA) syringe driver. Outcome measures included visual analogue scores (VAS) for pain, time to first bolus of IV morphine PCA, and total amount of morphine PCA used.

Results: The patients who received fentanyl demonstrated a significant decrease in their mean pain VAS, an increase in the time to first PCA bolus, and a 41% reduction in the total PCA morphine received. No patients had respiratory compromise requiring treatment. There was no significant difference between the two groups with respect to age, gender, and case mix.

Conclusion: Intrathecal fentanyl is effective at reducing pain and morphine PCA use after lumbar spinal surgery with minimal respiratory depression.