Evaluation of Epidural Analgesic Paste Components in Lumbar Decompressive Surgery

Abstract

Adjuncts for pain management in lumbar decompressive surgery are needed to reduce narcotic consumption and promote early mobility. To evaluate the efficacy and active components of a previously described epidural analgesic paste in controlling postoperative pain and facilitating early discharge from hospital after lumbar decompressive surgery. A randomized double-blind controlled trial was conducted. Two-hundred and one patients were randomized to 1 of 4 analgesic epidural pastes at the time of lumbar spinal surgery: combination paste (morphine + methylprednisolone), steroid paste (methylprednisolone alone), morphine paste (morphine alone), or placebo. The primary outcome measures used were analgesic consumption and the McGill Pain Questionnaire (MPQ). Secondary outcome measures were: modified American Spinal Cord Injury Association (ASIA) score, Short Form 36 General Health Survey (SF-36), Aberdeen Pain Index (ABPI), time to ambulation and time to discharge from hospital. Administration of combination and steroid paste, but not morphine paste, resulted in a statistically significant reduction in mean pain rating index (PRI) and present pain intensity (PPI) components of the MPQ in the first 3 days after surgery. Likewise, postoperative in-patient narcotic analgesic consumption was reduced in the combination paste and steroid paste group, but not in the morphine paste group. No difference in time to ambulation or discharge, SF-36 scores, ABPI scores, or neurologic recovery was observed. An analgesic paste containing methylprednisolone acetate is effective at reducing postoperative pain after lumbar decompressive surgery. Mixing effective doses of morphine sulfate in the paste abrogates the expected analgesic effects of epidural morphine.