Effects of a Single-Dose Interscalene Block on Pain and Stress Biomarkers in Patients Undergoing Arthroscopic Rotator Cuff Repair: A Randomized Controlled Trial.

Abstract

To compare the effects of a single-dose interscalene block and general anesthesia (SISB/GA) with the effects of GA only in the early postoperative period after arthroscopic rotator cuff repair by evaluating subjective pain visual analog scale scores and objective pain-related stress biomarkers. Patients refractory to conservative treatment of the affected shoulder were enrolled in this prospective, randomized endpoint study. Patients diagnosed with a rotator cuff tear (1-4 cm) based on magnetic resonance imaging were included. Exclusion criteria were small (<1 cm) and massive (>4 cm) rotator cuff tears. Thirty-one patients each were randomized into the SISB/GA and GA treatment groups. Preoperative pain scores were measured at 6:00 AM on the day of surgery, measured again at 1 and 6 hours postoperatively, and then every 6 hours until 3 days postoperatively. Blood sampling was performed to evaluate the stress biomarkers insulin, dehydroepiandrosterone sulfate, and fibrinogen preoperatively at 6:00 AM on the day of surgery and postoperatively at 18, 42, and 66 hours (6:00 AM on postoperative days 1-3). Pain scores were significantly decreased in the SISB/GA group (2.50 ± 0.94) versus the GA group (3.82 ± 1.31) on the day of surgery (P < .001), and especially at 6 hours postoperatively (SISB/GA: 2.42 ± 1.43; GA: 4.23 ± 2.17; P < .001). Insulin was decreased significantly in the SISB/GA group (10.55 ± 7.92 μU/mL) versus the GA group (20.39 ± 25.60 μU/mL) at 42 hours postoperatively (P = .048). There was no significant change in dehydroepiandrosterone sulfate or fibrinogen over time (P > .05). After arthroscopic rotator cuff repair, an SISB effectively relieved pain on the day of surgery without any complications. In addition, insulin levels were significantly reduced at 42 hours postoperatively. Level I, prospective randomized controlled trial.