Abstract:Objective To investigate the effects of ultrasound-guided quadratus lumborum block (QLB) via different approaches on stress, microcirculation, and postoperative analgesia in patients undergoing hysteroscopic surgery. Methods A total of 80 patients scheduled for hysteroscopic surgery at the 910th Hospital of the Joint Logistic Support Force from September 2020 to September 2023 were selected as the study subjects. They were randomly divided into a control group and an observation group using a random number table method. Both groups received ultrasound-guided QLB for analgesia. The control group underwent the anterior approach to the quadratus lumborum muscle (n=40), while the observation group underwent anterolateral approach to the lateral supra-arcuate ligament (n=40). The Visual Analog Scale (VAS) was used to assess pain levels at 2 hours (T1), 4 hours (T2), 12 hours (T3), and 24 hours (T4) postoperatively. Differences in stress indicators [angiotensin Ⅱ (Ang-Ⅱ), cortisol (Cor)]and microcirculation indicators (loop morphology score and blood flow state score in nailfold microcirculation) were compared between the two groups. The incidence of postoperative 24-hour analgesic rescue, analgesic satisfaction, and the occurrence of adverse reactions were recorded for both groups. Results Repeated measures analysis of variance showed that for VAS scores, stress indicators, and microcirculation indicators, the between-group effects and time effects were statistically significant (P< 0.05), but the between-group × time interaction effects for stress and microcirculation indicators were not statistically significant (P>0.05). The VAS scores and serum levels of Ang-Ⅱ and Cor, as well as loop morphology and blood flow state scores at T1 to T4 in the observation group, were lower than those in the control group (P<0.05). The incidence of 24-hour postoperative analgesic rescue in the observation group was lower than that in the control group (12.50% vs 37.50%, χ²=6.667, P=0.010), and analgesic satisfaction was superior to the control group (Z=3.452, P=0.001). There was no statistically significant difference in the incidence of adverse reactions between the control group and observation group (25.00% vs 10.00%, χ²=3.117, P=0.078). Conclusion For patients undergoing hysteroscopic surgery, ultrasound- guided QLB at the lateral supra-arcuate ligament demonstrates superior effects on postoperative stress, microcirculation, and analgesia compared to the anterior approach QLB, with a high safety profile.