Efficacy of the morphine-Adcon-L compound in the management of postoperative pain after lumbar microdiscectomy

OBJECTIVE: Epidural analgesia is a pharmacological technique for operative and postoperative pain control. It has been used with lumbar microdiscectomy to facilitate management of surgical pain, shorten patient recovery time, and increase patient satisfaction with the procedure and the hospital stay. Adcon-L (Gliatech, Inc., Cleveland, OH) (adhesion control in a barrier gel) has been demonstrated to act as a barrier to the development of epidural fibrosis after lumbar procedures, minimizing the formation of fibrotic scar and improving the long-term outcome. In this study, we used Adcon-L as a vehicle to administer 1 mg of morphine epidurally to patients who underwent lumbar microdiscectomy. Our objective was to evaluate the safety and analgesic efficacy of this compound. METHODS: A randomized, controlled, double-blind study was conducted in 100 patients. Patients were randomized to two groups: the morphine-Adcon-L (M-ADL) group (n = 51 patients) or the Adcon-L control group (n = 49 patients). Outcome measures included: 1) a visual analog scale to assess the intensity of spontaneous low back and radicular pain, 2) a straight leg-raising maneuver to assess the degree of leg elevation in relation to evoked sciatic pain, 3) postoperative time to comfortable walking, 4) duration of postoperative hospitalization, 5) required amount of postoperative analgesics, and 6) postoperative work time loss. RESULTS: No intraoperative or postoperative complications were observed. No clinically relevant adverse events, such as urinary retention, respiratory disturbances, or wound infections were reported in the M-ADL group. At the time of hospital discharge, results were as follows: 1) the M-ADL group had significantly lower pain intensity scores (mean value of postoperative visual analog scale, 12.3 mm ± 0.9 in the M-ADL group versus 24.7 mm ± 11.5 in the control group [P < 0.0001]); 2) the M-ADL group consumed significantly less analgesics: 57.4% of M-ADL patients versus 95.9% of controls received analgesics in the hospital, and 23.5% of M-ADL patients versus 55.1% of controls used analgesics at home (P < 0.0001); 3) the M-ADL group had significantly shorter hospital stays (1.37 ± 0.07 d versus 2.53 ± 0.12 d in the control group [P < 0.0001]); 4) the M-ADL group had a significantly higher degree of symptomatic leg elevation in the straight leg raising (mean postoperative straight leg-raising test, 64.41 degrees ± 1.59 versus 57.77 degrees ± 1.85 in the controls [P = 0.02]); and 5) the M-ADL group lost significantly less postoperative work time (21.67 ± 0.92 d versus 29.47 ± 1.18 d in the control group). In addition, at 1 year of follow-up, there was no clinical evidence of late-onset neurological complications. CONCLUSION: The epidural application of the compound M-ADL after lumbar microdiscectomy was found to be safe and effective, and it significantly improved postoperative pain control and return to function.