Advantages of Transmuscular Quadratus Lumborum Block via Subfascial Approach Versus Extrafascial Approach for Postoperative Analgesia After Laparoscopic Cholecystectomy: A Randomized Controlled Study.

"Supported by the Science and health joint medical research project of Chongqing (No: 2020MSXM013 and 2020FYYX076) to W.-q.H and B.Y., National Natural Science Foundation of China (No: 82070630 and 82100658) to B.Y. and Y.-j.L., Chongqing Talents Project (No: CQYC202103080) and the Third Military Medical University Talent Pool Project (No: XZ-2019-505-027) to B.Y."

"The trial protocol was approved by the Ethics Committee of the First Affiliated Hospital of Third Military Medical University (Scientific Research No.16, 2017) and registered at ClinicalTrials.gov (registration NO. NCT03421821, the principle investigator: K.-z.L.) on January 22, 2018. We did not enroll any patients until we completed the registration of the trial on line. Written informed consent was obtained from each enrolled patient. Between February 25 to September 17, 2018, patients scheduled for elective LC surgery with American Society of Anesthesiologists physical status I and II, age 18 to 75 years old, body mass index of 17 to 32 kg/m2, and with operation time <2 hours were enrolled (Fig. ). All patients with a history of local anesthetic allergy, chronic opioid usage, or communicative disorders were excluded from the study. Patients were randomly allocated to either the subfascial group (needle tip unpunctured the ATLF) or the extrafascial group (needle tip punctured the ATLF) using a random number table. The investigator who took charge of patient recruitment, allocation, and quality control did not participate in perioperative anesthesia and pain management. The quadratus lumbar block and general anesthesia were conducted by the same experienced anesthetist. Postoperative pain management, related evaluation, follow-up, and data collection were conducted by another doctor who was not involved with treatment of the patients (the researcher). The researcher was blinded with the study protocol, independently harvested the all above outcome measures."