Comparative study of epidural application of morphine versus gelfoam soaked in morphine for lumbar laminectomy

BACKGROUND: Epidural application of morphine has been used for postoperative analgesia following spine surgery but short duration of action of single application limits its widespread use. MATERIALS AND METHODS: One hundred and fifty patients undergoing lumbar laminectomy were randomly allocated to two groups of 75 patients each. Anesthetic technique was standardized in both the groups. In Group I, at the completion of laminectomy, a 5 × 1-cm strip of gelfoam soaked in 5 mg morphine (1 mg/ml) was contoured to be placed in the epidural space whereas, in group II, gelfoam soaked in saline was placed in the epidural space and 5 mg morphine (1mg/ml) was instilled over the intact epidural space. Analgesic consumption for 48 hours, time-of first analgesic request, time of ambulation, time of discharge from post anesthesia care unit (PACU) and hospital and adverse effects were recorded. The data was analyzed using appropriate statistical tests. RESULTS: Mean analgesic consumption in 48 hours was significantly less in group I (8.47 ± 3.674 mg) as compared to group II (24.80 ± 6.009 mg). Supplemental analgesia was requested at 30.03 ± 6.796 hours in Group I, vs 10.25 ± 2.243 in group II (P < 0.001). Group I patients were discharged earlier from PACU as compared to group II (P < 0.001) though time of discharge from hospital was similar in both the groups. There were no major adverse effects except pruritis, which was observed in 30.6% patients in group I and 37.3% in group II (statistically insignificant (P > 0.01)). CONCLUSION: Epidural application of morphine soaked in gelfoam is an effective method for prolonging the postoperative analgesia after spine surgery.