Analgesia for Arthroscopic Shoulder Surgery: A Comparison of Interscalene and Subacromial Levobupivacaine with IV Morphine Patient Controlled Analgesia

Abstract

Backgorund and Aim : Arthroscopic shoulder surgery (ASS) may result in severe postoperative pain. We compared a continuous subacromial infusion of levobupivacaine after single shot interscalene block (ISB), a continuous ISB with levobupivacaine and intravenous morphine PCA with preoperative ISB for patients undergoing arthroscopic shoulder surgery. Methods : After obtaining ethics committee approval and informed consent 120 patients were randomized to three groups, Group 1 (G1) ISB with 0.5% levobupivacaine (l-bupi) (30 mL) followed by a postoperative subacromial infusion: 0.125% l-bupi 5 mL/h basal infusion, 5mL bolus dose and a 20 min lockout time or; Group 2 (G2) ISB with 0.5% l-bupi (30 mL) followed by a postoperative interscalene infusion: 0.125% l-bupi 5 mL/h basal infusion, 5mL bolus dose and a 20 min lockout time; or Group 3 (G3) ISB with 0.5% l-bupi (30 mL) followed by a postoperative morphine PCA 0.3 mg/h basal infusion, 1mg bolus dose and a 20 min lockout time. Infusions were maintained for 24 hours. Results : The median VAS scores in the postanesthesia care unit and at 4 h were not different. The median VAS scores at 8, 12, and 24 hours were ≤ 4 in all groups; but they were significantly lower in G2. There were no differences in VAS values of G1 and G3 patients. Additional analgesic requirements were lower in G2 (60% vs 7.5% vs 50% respectively for G1, G2 and G3). Nausea and vomiting were more common in G3. Patients’ satisfaction scores of groups were 8 ± 0.7 in G1, 9 ± 0.8 in G2 and 7.1 ± 0.9 in G3 (G1 vs G3, p< 0,001). Conclusions : Subacromial infusion provided good postoperative analgesia for ASS, but it’s less effective than ISB, but is superior to intravenous PCA because it causes less nausea and vomiting with higher patient satisfactions. Subacromial infusions can be considered as an alternative for postoperative pain treatment after ASS when ISB is contrainticated.