Quadratus lumborum block (QLB) is clinically used for postoperative analgesia of abdominal or hip surgery, which can reduce the dose of general anesthetic, inhibit postoperative pain, and promote postoperative rehabilitation. However, accumulated studies have shown several drawbacks of QLB, such as only a small portion of local anesthetic spread into the thoracic paravertebral space, relatively longer onset time, and easily-influenced block effect by the integrity of lumbar fascia, etc. Therefore, on the basis of traditional anterior QLB, our group proposed the techniques of a supra-arcuate ligament block, which include a paramedian short-axis scanning approach, paramedian long-axis scanning approach, infra-lateral arcuate ligament QLB with the apposition zone between diaphragm and quadratus lumborum as drug diffusion target and supra-arcuate ligament block under direct laparoscopic visualization. Recent studies have demonstrated that the supra-arcuate ligament blocks have the advantages of clear anatomy, are easy to perform, and have rapid onset, which avoid some drawbacks of the conventional QLB techniques. This article reviews the anatomical basis, sonoanatomy, technical points, and clinical considerations of supra-arcuate ligament blocks.

Purpose Local anesthetics can spread into the subendothoracic fascia compartment via the arcuate ligament and apposition zone of the diaphragm after the anterior quadratus lumborum blocks. Therefore, a new block may be achieved if local anesthetic is administered into the diaphragmatic apposition zone (DAZ) under direct laparoscopic visualization by surgeons. Therefore, we evaluated the sensory loss and postoperative analgesic efficacy of this new block in patients receiving laparoscopic nephrectomy. Methods A total of 28 patients scheduled to receive elective laparoscopic nephrectomy under general anesthesia were enrolled in this study. The DAZ blocks were performed in patients under direct laparoscopic visualization with 20 mL of 0.5% ropivacaine before the dissected kidneys or renal tumors were taken out from the incision. All patients received the intravenous patient-controlled analgesia after surgery. The dermatomes of sensory loss and the muscle weakness of quadriceps femoris were assessed at 2 h post-surgery in the wards. The postoperative pain was scored. The opioid consumption in the first 24 h after surgery was recorded. Results The average number of dermatomes of sensory block was 8.6 ± 1.2. The highest level of sensory loss was T6 (T5-T6) [median (interquartile range, IQR)], and the lowest level of sensory block was L1 (L1–L2). The postoperative pain scores at rest or on movement at 2 h, 6 h, 12 h, 24 h and 48 h were kept at the low levels (less than 4). The muscle strength of the quadriceps femoris evaluated was 5 (5–5) points [median (IQR)]. Total dose of intravenous morphine equivalent consumption in the first 24 h after surgery was 21.2 ± 4.1 mg. Conclusion The DAZ block manifests a wide dermatomal coverage of sensory loss and is associated with the low levels of postoperative pain intensity and opioid use. It provides a new postoperative analgesia option for patients undergoing laparoscopic nephrectomy.