The Analgesic Efficacy of Adding Dexmedetomidine to Ropivacaine in Preoperative Interscalene Block for Arthroscopic Rotator Cuff Repair.

BACKGROUND

Effective postoperative pain management is essential after arthroscopic shoulder surgery. Ultrasound-guided interscalene block (ISB) is widely used for perioperative analgesia; however, the benefits of adding dexmedetomidine to local anesthetics remain uncertain.

OBJECTIVES

This study aimed to evaluate the analgesic efficacy and hemodynamic effects of dexmedetomidine as an adjuvant to ropivacaine for ultrasound-guided ISB in patients undergoing arthroscopic rotator cuff repair.

METHODS

This double-blind randomized clinical trial included patients aged ≥ 18 years with American Society of Anesthesiologists physical status I-III who were scheduled for elective arthroscopic rotator cuff repair. Forty-two patients were randomly allocated in a 1:1 ratio using a random-number table to receive ultrasound-guided ISB with either 20 mL of 0.25% ropivacaine plus 2 mL of normal saline (R group) or 20 mL of 0.25% ropivacaine plus dexmedetomidine (1.5 μg/kg), diluted to a total volume of 2 mL (ropivacaine-dexmedetomidine (RD) group). Randomization and preparation of the study solutions were performed by an independent investigator. The anesthesiologist performing the block, the patients, and the postoperative outcome assessor remained blinded to the treatment allocation. Pain intensity was assessed using the Numerical Rating Scale (NRS) in the recovery room and at 2, 6, 18, and 24 hours postoperatively. Intraoperative remifentanil consumption, time to the first patient-controlled intravenous analgesia (PCIA) request, number of PCIA requests, pethidine requirements, and hemodynamic variables were recorded. Data were analyzed using the Kolmogorov-Smirnov test, independent-samples t-test, Mann-Whitney U test, chi-square test, or Fisher's exact test, as appropriate.

RESULTS

Forty patients completed the study and were included in the per-protocol analysis (20 patients in each group). Compared with the R group, the RD group had significantly lower intraoperative remifentanil consumption (0.11 ± 0.02 vs 0.24 ± 0.04 μg/kg/min, P < 0.001), a longer time to the first PCIA request (17.57 ± 0.93 vs 13.37 ± 1.25 hours after ISB, P < 0.001), fewer PCIA requests (4.50 ± 1.19 vs 9.95 ± 1.50, P < 0.001), a longer time to the first pethidine administration (19.20 ± 0.83 vs 16.33 ± 1.52 hours after ISB, P < 0.001), and fewer pethidine administrations (0.35 ± 0.67 vs 3.45 ± 1.05, P < 0.001). NRS pain scores at 18 and 24 hours were also significantly lower in the RD group. No significant between-group differences were observed in systolic blood pressure, diastolic blood pressure, and heart rate.

CONCLUSIONS

The addition of dexmedetomidine to ropivacaine for an ultrasound-guided interscalene block significantly prolonged postoperative analgesia, reduced intraoperative remifentanil consumption, decreased postoperative analgesic requirements, and improved postoperative pain control, without significant adverse effects on hemodynamic parameters, in patients undergoing arthroscopic rotator cuff repair.