[Comparison of the analgesic effects of infraspinatus-teres minor interfascial block and interscalene block under ultrasound guidance in patients undergoing arthroscopic shoulder surgery].

Objective: To compare the postoperative analgesic efficacy of ultrasound-guided infraspinatus-teres minor interfascial block and interscalene block in shoulder arthroscopic surgery. Methods: A total of 74 patients undergoing shoulder arthroscopic surgery at the Affiliated Hospital of Jiaxing University from December 2023 to February 2024 were prospectively included, whose age ranged from 18 to 80 years and the American Society of Anesthesiologists (ASA) grade were Ⅰ-Ⅲ. Patients were divided into two groups using block randomization: infraspinatus-teres minor interfascial block group (observation group) and interscalene block group (control group), with 37 cases in each group. In the anesthesia preparation room, all patients received nerve blocks under ultrasound guidance with 20 ml of 0.375% ropivacaine. Patient-controlled intravenous analgesia (PCIA) was administered to all patients following surgery. The primary outcome was the area under the curve (AUC) of the numeric rating scale (NRS) for pain within 24 hours postoperatively. Secondary outcome measures included the highest NRS score within 48 hours postoperatively, the amount of sufentanil used via PCIA within 48 hours postoperatively, the incidence of rescue analgesia and rebound pain, QoR-40 scores, and the rate of postoperative nausea and vomiting within 24 hours. The non-inferiority margin for the AUC of NRS scores between the two types of regional nerve blocks was set at "2.6". Results: A total of 35 patients were included in the observation group [17 males, 18 females, aged (58.1±9.1) years], and 36 patients were included in the control group [12 males, 24 females, aged (57.0±9.8) years]. The AUC of the NRS scores at rest within 24 hours post-operation was 51.7±10.9 in the observation group and 62.6±13.6 in the control group. The difference in AUC between the two groups was -10.9 (95%CI:-16.8--5.1), with the upper limit of the 95%CI falling below the predefined non-inferiority margin of "2.6" (non-inferiority P<0.001). The highest NRS score [M (Q₁, Q₃)] within 48 hours post-surgery was 3 (3, 4) in the control group, which was significantly higher than the observation group's score of 2 (2, 3) (P<0.001). During the postoperative period of 0-12 hours, the observation group received a median dose of 12 (10, 14) μg of sufentanil, which was significantly higher than the control group's dose of 8 (6, 10) μg (P<0.001). During the postoperative period of 12-24 hours, the observation group received a median dose of 8 (8, 10) μg of sufentanil, which was significantly lower than the control group's median dose of 12 (10, 14) μg (P<0.001). During the postoperative period of 24-48 hours, there was no statistically significant difference in the dose of sufentanil between the two groups of patients (P=0.548). In the observation group, the incidence of rescue analgesia within 48 hours postoperatively was 0 (0/35), which was lower than that of the control group at 22.2% (8/36) (P=0.010). The occurrence of rebound pain in the observation group was 0 (0/35), and the control group was 11.1% (4/36), no statistically significant difference was found between two groups (P=0.130). In the observation group, the QoR-40 score within 24 hours post-operation was 180.2±3.2, which was higher than the control group's score of 175.8±4.7 (P<0.001). There was no statistically significant difference in the incidence of postoperative nausea and vomiting within 24 hours between the two groups (P=0.372). Conclusion: Ultrasound-guided infraspinatus-teres minor interfascial block demonstrates a comparable analgesic effect to interscalene block in shoulder arthroscopic surgery within the first 24 hours postoperatively.