A comparative study on the efficacy of PENG block with either supra-inguinal fascia iliaca block or circum-psoas block for postoperative analgesia in elderly patients undergoing surgery for proximal hip fractures

The fascia iliaca block is a commonly used compartment block for cutaneous analgesia for hip surgery. The hip joint is innervated by branches of the femoral nerve (FN), obturator nerve (ON), and sciatic nerve (SN). The lateral femoral cutaneous nerve (LFCN) should also be blocked if the surgical incision extends to the lateral side of the thigh. The FN, ON, and LFCN are all part of the lumbar plexus, implying that blocking the lumbar plexus is an elegant way to provide postoperative analgesia for THA. The fascia iliaca compartment block (FICB) can be regarded as an anterior approach of the lumbar plexus. This block anesthetizes the lateral femoral cutaneous nerve but has reported failure rates of 10% to 37%. Moreover, a recent study failed to demonstrate the benefit of a “classic” transverse FICB at the level of the FN for postoperative analgesia after hip arthroplasty. Supra-inguinal fascia iliaca (SIFI) block is a novel regional anaesthesia technique that was first described by Hebbard et al. in 2015 as an alternative technique to the classic infrainguinal fascia iliaca block on the presumption that it will provide a wider local anaesthetic spread and better coverage of the lateral femoral cutaneous nerve. The course of the lateral femoral cutaneous nerve below the inguinal ligament is variable as opposed to consistent above the inguinal ligament in the pelvis. The authors used a supra-inguinal ultrasound-guided technique and placed local anaesthetic directly into the iliac fossa and found that it leads to extensive fluid spread throughout the iliac fossa. They described consistent staining of the femoral nerve and lateral femoral cutaneous nerve in their cadaveric dye study. Subsequently, many clinical studies demonstrated its analgesic efficacy. One study comparing lumbar plexus block versus SIFI block for total hip arthroplasty found that SIFI block provided equivalent analgesic efficacy and longer duration of analgesia.

Circumpsoas block (CPB) is a recently described block which is an anterior myofascial plane block for lumbar plexus elements. In an attempt to improvise the analgesia in patients with femoral fractures,  local anesthetic was deposited deep to anterior psoas fascia under ultrasound guidance to block lumbar plexus elements which emerge lateral, anterior, and medial to the psoas major muscle. . Clinical and computed tomography contrast studies revealed that a continuous CPB infusion with a catheter provided a reliable block of the lumbar plexus elements. No adverse were events noted. Hence, it is implied that US guided CPB is a reliable technique for managing postoperative pain after surgery of femur fractures. Since SIFI block does not provide coverage for obturator nerve, we hypothesized that PSB would provide a superior pain relief compared to SIFI block. At present, no study has compared these two regional anesthesia techniques. Hence, we decided to compare the two techniques for postoperative analgesic efficacy.