Anterior Iliopsoas Muscle Space Block Versus Supra-Iliac Anterior Quadratus Lumborum Block for Analgesia in Total Hip Arthroplasty: A Randomized Controlled Trial

The acetabulum and the head of the femur combine to produce a traditional ball and socket joint in the hip. The lumbar (L1-L4) and sacral (L4-S4) plexuses both innervate the hip joint, and its sensory innervation is from the femoral (FN), obturator, and sciatic nerves with contribution from the superior gluteal nerve and nerve to quadratus femoris. Cutaneous innervation is by lateral femoral cutaneous (LFCN), subcostal iliohypogastric nerve, and the superior cluneal nerves which predominately arise from the dorsal rami of L1.

The lumbar plexus nerves, including the femoral, obturator, and lateral femoral cutaneous nerves, lie within the psoas major (PM) muscle. These nerves then exit the PM to lie within the iliopsoas compartment, between the iliacus and PM muscles. The sacral plexus is located also in the caudal extension of this anatomical space. The iliacus and psoas muscles are wrapped by the fascia iliaca. The fascia iliaca fuses superiorly with the anterior thoracolumbar fascia (transversalis fascia) that wrapped both the quadratus lumborum (QL) and the psoas muscles.

Total hip arthroplasty (THA) is a common orthopedic surgical procedure that has been successfully utilized to treat hip fractures since 1960 [4] as well, it is considered the treatment of choice for osteoarthritis of the hip joint. Both implants' types cemented and uncemented can provide good fixation, resulting in favorable long-term outcomes [5]. One of the keys to a patient's recovery following THA surgery is effective postoperative pain management. Nowadays, the concept of pain management with multimodal analgesia and regional anesthesia plays a crucial role in postoperative analgesia reducing opioids consumption and decreasing the time to mobilization. Numerous regional anesthetic techniques have been used, including patient-controlled epidural analgesia, intrathecal morphine, fascia iliaca block, lumber plexus block, sacral plexus block, and local infiltration analgesia. However, each of these techniques has specific limitations that prevent them from being the analgesic technique of choice for THA.

The ultrasound-guided (QL) block is a regional anesthetic technique that was initially proposed as an analgesic modality for abdominal surgery through many approaches: the lateral QL (QL1) block, the posterior QL (QL2) block, and the anterior QL (transmuscular) block The anterior QL block has been performed at the L3-L4 level also been used in hip surgery case reports.

A supra-iliac approach to the anterior QL block that is performed at a lower level than traditional anterior QL block approaches is considered a new approach discovered by Elsharkawy et al., and they found that a single injection between QL and Psoas muscle at the level of L5, successfully block the lumbar plexus and provide analgesia in patients undergoing total hip arthroplasty.