The Effects of Adding Dexamethasone in the Quadratus Lumborum Block

The quadratus lumborum block is widely used in abdominal surgery for post-operative analgesia. It is now also used for pain relief after hip surgery. Under the traditional blocking method, a high concentration of long-acting local anesthetic is used in order to achieve a long-term blocking effect. However, this is also likely to cause the patient's quadriceps weakness during the block period, increasing the risk of the patient falling during rehabilitation. It also increases systemic local anesthetic poisoning and may even trigger the risk of serious side effects such as cardiac arrest. Ropivacaine is a novel long-acting topical amine anesthetics that lasts long and has anesthetic and analgesic effects. Its pharmacological characteristics are low cardiotoxicity, sensory block and motor block separation at low concentrations more obvious, and with the external peripheral vasoconstriction. Therefore, the drug is especially suitable for postoperative analgesia. Dexamethasone is a synthetic corticosteroid for the treatment of a wide range of symptoms including rheumatic diseases, certain skin diseases, severe allergies, asthma, chronic obstructive pulmonary disease, cerebral edema, and may also be combined with antibiotics for tuberculosis patients. It is becoming more common to use steroids as an adjuvant to local anesthetics in peripheral nerve block. Steroids have neurological blockade effects by blocking the nociceptive transmission of pith-type C-fibers and inhibiting the release of ectopic neurons. Dexamethasone, as a local anesthetic adjuvant in peripheral nerve block, has also been widely studied recently. In order to reduce the incidence of long-acting topical anesthetics from the nerve block in the quadratus lumborum block, reducing the local anesthetic concentration is a feasible method. However, this will also result in a shorter time to neurological block. The investigators hypothesized that the addition of Dexamethasone 5 mg to low concentrations (0.25%)