Evaluation of peripheral morphine analgesia for lumpectomy and axillary node dissection: A randomized, double-blind, placebo-controlled study

Background and Objectives. Morphine may elicit potent antinociceptive effec ts by binding and activating peripheral opioid receptors. However, the resu lts in clinical studies have varied. We examined the postoperative analgesi c effects of incisional morphine in patients undergoing lumpectomies and ax illary node dissections for breast cancer. For this purpose, a concentratio n of morphine within the range (0.25-0.6%) of those utilized in previous st udies for postarthroscopy analgesia was chosen (0.6%). Methods. Forty-five patients scheduled to undergo a lumpectomy and axillary node dissections fo r breast cancer were enrolled in this study after receiving Ethics Committe e approval and patient consent. Patients were randomized to undergo irrigat ion of the surgical sites for 5 minutes prior to skin closure with 6 mg mor phine diluted in 100 mt 0.9% normal saline (NS) and placebo intramuscular ( IM) (peripheral MS group), 100 mL of 0.9% NS alone and placebo IM (placebo group), or 100 mt of 0.9% NS and 6 mg morphine IM in the deltoid muscle (IM MS group) in a double-blind fashion. In the postanesthesia care unit, pati ents received fentanyl via a patient-controlled analgesia (PCA) device prog rammed to deliver 25 mu g every 10 minutes to a maximum dose of 150 mu g/h. Patients were evaluated for pain using a visual analog scale card from 0-1 0, opioid consumption, and incidences of side effects at 2, 6, 12, 18, and 24 hours after surgery. Results. All patients had adequate analgesia at res t and during arm movement with visual analog pain scores (VAPS) < 3/10 thro ughout the study period. There were no significant differences in demograph ics, total fentanyl consumption (500 vs, 475 vs 933 mu g, respectively; P = .2), VAPS at rest and during arm movement as well as fentanyl consumption at the different evaluation points among the three groups. Conclusions. The se results suggest that under the conditions of the study protocol, there i s no value in utilizing morphine in solution at the surgical site for posto perative lumpectomy and axillary node dissection analgesia.