Effect of interscalene nerve block on the inflammatory response in shoulder surgery: a randomized trial

Abstract

Background: Comparing techniques of general anesthesia and regional anesthesia in arthroscopic shoulder surgery, some studies have shown differences in the intensity of immediate postoperative pain and neuroendocrine response, but the inflammatory response when using balanced general anesthesia (BGA) vs. an ultrasound-guided (USG) single-dose interscalene block (SDIB) has not been compared.

Materials and methods: In a single-center, prospective, randomized clinical trial, the inflammatory response of 2 groups of 10 patients scheduled to undergo arthroscopic shoulder surgery was evaluated through measurement of a panel of cytokines that act on cells of the adaptive immune response to promote or inhibit inflammation, chemokines involved in chemotaxis, the erythrocyte sedimentation rate (ESR), the high-sensitivity C-reactive protein (CRP) level, and the white blood cell (WBC) count in 3 blood samples (before anesthesia, immediately postoperatively, and 24 hours postoperatively) with 2 types of anesthesia (BGA vs. USG SDIB). Postoperative pain intensity (immediately, at 12 hours, and at 24 hours) was also assessed.

Results: The ESR and CRP level increased significantly at 24 hours after surgery; however, the increase in ESR (P < .0001) and CRP level (P < .0001) was lower in the USG SDIB group. Significant increases in the levels of soluble interleukin 2 receptor α (P = .022) and interleukin 12p40 (P = .016) occurred in the immediate postoperative period in the USG SDIB group. Immediate postoperative pain showed a significant increase (P < .001) in the BGA group.

Conclusions: In arthroscopic shoulder surgery, the use of a USG SDIB compared with the use of BGA is possibly associated with improved pain control in the immediate postoperative period and lower immunosuppression, even at 24 hours after surgery.

Keywords: Interscalene nerve block; arthroscopic shoulder surgery; balanced general anesthesia; inflammatory response; postoperative pain; shoulder surgery.