Volume Versus Concentration: Clinical Effectiveness of Single Shot Quadrates Lumborum Block Using Either a High Volume/Low Concentration or Low Volume/High Concentration Injectate for Total Hip Arthroplasty.

There is Controversy about what is more critical volume or concentration to achieve an optimum analgesic treatment with quadratus lumborum block. From the experiences of the authors, the regular dose of 20 ml of Bupivacaine at 0.375% concentration could not be enough in some cases to produce an optimum analgesic treatment, especially in hip arthroplasties. What is proposed in this study is to evaluate whether the volume injected in the quadratus lumborum block is more important than the concentration of the local anesthetic in terms of control of pain during the next 24 hours after surgery and opioid consumption.