Effects of anterior approach to quadratus lumborum block on postoperative cognitive function following hip surgery in elderly patients: A randomized controlled clinical trial

Abstract

Background: Peripheral nerve block, including the quadratus lumborum block (QLB), has been used for postoperative analgesia in hip surgery. However, the effects of QLB on cognitive function after hip surgery remain unknown. This study aimed to assess the effects of the anterior approach to QLB on postoperative cognitive function in elderly patients undergoing hip surgery. Methods: Sixty elderly patients who underwent hip surgery from May 2021 to May 2022 were randomly divided into the QLB (n = 30) and control groups (n = 30). The Montreal Cognitive Assessment (MoCA) score was measured one day preoperatively and seven and 30 days postoperatively. The incidence of postoperative cognitive dysfunction (POCD) was examined seven and 30 days postoperatively. The visual analog scale (VAS) scores at rest and Bruggrmann comfort scale (BCS) scores 6 h (t1), 12 h (t2), 24 h (t3), and 48 h (t4) after surgery were assessed. The plasma high mobility group box protein 1 (HMGB1) and levels of interleukin-6 (IL-6) were evaluated 1 h preoperatively (baseline) and 24 h postoperatively (day 1). The requirement for rescue analgesia, time to first off-bed activity, and adverse effects after surgery were also recorded. Results: Compared with the control group, the incidence of POCD was significantly lower in the QLB group seven days postoperatively (10.7% vs. 34.5%, P = 0.033), but no difference at 30 days postoperatively (3.6% vs. 10.3%, P = 0.317). There was no significant difference in MoCA scores between the two groups at one day preoperatively and 30 days postoperatively. However, the MoCA scores at seven days postoperatively were higher in the QLB group than in the control group (P < 0.05). In the QLB group, the VAS scores at t1, t2, and t3 were lower, and the BCS scores at t1, t2, and t3 were higher than those in the control group (P < 0.05). The patients in the QLB group reported significantly fewer requirements for rescue analgesia (P < 0.05). The plasma levels of HMGB1 and IL-6 at 24 h postoperatively in the QLB group were significantly lower than in the control group (P < 0.05). The time to first off-bed activity was shorter in the QLB group (P < 0.05). There was no significant difference in the incidence of postoperative complications between the two groups. Conclusions: Anterior QLB given to elderly patients undergoing hip surgery could promote early postoperative cognitive function recovery, provide adequate postoperative analgesia, and inhibit the release of inflammatory factors. Trial registration: Chictr.org.cn identifier ChiCTR2000040724 (Date of registry: 08/12/2020, prospectively registered).