Abstract
BackgroundQuadratus lumborum block (QLB) is increasingly gaining popularity as a novel abdominal truncal block in abdominal surgery; however, the mechanism of QLB is not yet thoroughly illustrated. The focus of our study is transmuscular QLB (TMQLB), as the latest anatomical evidence shows that anesthetics spread into the thoracic paravertebral space to exert an analgesic effect. Therefore, we designed this study to compare TMQLB with thoracic paravertebral block (TPVB) in laparoscopic renal surgery in the hope of providing clinical evidence on the analgesic mechanism of TMQLB and its application in laparoscopic renal surgery.MethodsThis trial is a prospective, randomized, single-center, open-label, parallel, three-arm, non-inferiority trial. We intend to include 120 participants undergoing laparoscopic nephrectomy and before surgery they will be randomized into three groups for postoperative pain control: TMQLB experimental group 1 (0.4 ml/kg body weight 0.5% ropivacaine), TMQLB experimental group 2 (0.6 ml/kg body weight 0.5% ropivacaine) or TPVB control group (0.4 ml/kg body weight 0.5% ropivacaine at vertebra T10). Patients will be excluded if they have allergy to anesthetics, infection at the injection site, are on coagulopathy or anticoagulants, on analgesics for chronic illness, have history of substance abuse or have a barrier to communication. Morphine is given in boluses of 1.5~2 mg by intravenous patient-controlled analgesia (IPCA) in the first 48 h after surgery. The primary outcome is the difference between TMQLB group 1 and the TPVB group in the mean visual analogue scale (VAS) pain score in the first 24 h after surgery. Secondary outcomes are the difference between TMQLB group 2 and the TPVB group in the mean VAS score in the first 24 h after surgery, cumulative morphine consumption, long-term pain control, dermatomal distribution of sensory loss, nausea score, pruritus score, ambulation time, time till recovery of bowel movement, quality of recovery, postoperative length of hospital stay and patient satisfaction with anesthesia. Safety data on procedure-related complications will also be summarized.DiscussionThis will the first randomized controlled trial to compare TMQLB with TPVB for analgesia in laparoscopic surgery. This trial aims to provide important clinical evidence to elaborate on the analgesic mechanism of TMQLB.Trial registrationClinicalTrials.gov, NCT03414281. Registered on 9 January 2018.
Highlights
Quadratus lumborum block (QLB) is increasingly gaining popularity as a novel abdominal truncal block in abdominal surgery; the mechanism of QLB is not yet thoroughly illustrated
The QLB 1 was first proposed by Blanco in 2007: the needle is inserted into the plane between the psoas major muscle and the quadratus lumborum (QL) muscle and the local anesthetic is injected into the anterolateral margin of the QL muscle, which is known as the lateral QLB [6]
Most of the current studies concentrate on the comparison of QLB with other abdominal blocks, especially the transversus abdominis plane (TAP) block, because QLB was originally proposed as a different form of TAP [4, 5, 15, 16]
Summary
Quadratus lumborum block (QLB) is increasingly gaining popularity as a novel abdominal truncal block in abdominal surgery; the mechanism of QLB is not yet thoroughly illustrated. There are four different approaches for QLB, with local anesthetic injected around the quadratus lumborum (QL) muscle from various directions. Børglum et al [8] described another approach, transmuscular QLB (TMQLB), whereby the needle is advanced through the latissimus dorsi and the QL muscle in a posterior-anterior direction with the injection performed anterior to the QL muscle. This approach is referred to as QLB 3 or anterior QLB. There is intramuscular QLB, whereby the anesthetic is injected directly into the QL muscle [5]
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