Quadratus Lumborum Block Versus Control for Total Hip Arthroplasty

Currently, regional anesthesia techniques for total hip arthroplasty are limited. Fascia iliac blocks have been employed to provide analgesia for hip surgeries with blockade of the femoral, lateral femoral cutaneous, and obturator nerves via injection of local anesthetic in the iliacus fascia. In addition, lumbar plexus blocks have also been employed for post-operative analgesia, but the complexity of the block is high, and complications including epidural anesthesia are not infrequent. The quadratus lumborum block is an abdominal truncal block in which local anesthetic is deposited into the thoracolumbar fascia or the quadratus lumborum muscle itself with the goal of providing analgesia to the ipsilateral T6 - L1 sensory dermatomes. It has already been demonstrated to provide effective post-operative analgesia for certain abdominal and pelvic surgeries, but its use in total hip arthroplasty is limited to case reports.

The block is accomplished by identifying the quadratus lumborum muscle, which originates from iliac crest and iliolumbar ligament, and inserted on transverse processes of upper four lumbar vertebrae and posterior border of the 12th rib. Local anesthetic is then deposited at the anterior, posterior or middle thoracolumbar fascia, or intramuscularly, depending on the technique used. Cadaveric studies8 have demonstrated dye spread to the lumbar nerve roots and nerves within the transversus abdominis plane (TAP). Carney et al9 described a "posterior TAP" block, now known to be synonymous with QLB, that demonstrated contrast spread to the thoracic paravertebral space from T5-L1. Case reports have described analgesia in the corresponding sensory dermatomes after QLB4, and have demonstrated efficacy in patient undergoing THA. The QLB block has potential to cover lateral femoral cutaneous nerve, femoral nerve, obturator nerve and portions of lumbar plexus.

This study has been designed to investigate the efficacy of the quadratus lumborum block as a primary method of providing post-operative analgesia in patients undergoing THA. Previous trials have demonstrated the effectiveness of the block for abdominal and pelvic surgeries, and case reports have shown its applicability in hip arthroplasty. In this randomized controlled study we aim to compare QLB (intervention) with control (no intervention) group in patients undergoing THA with regard to the VAS pain scores (at PACU arrival & discharge12, 24 & 36 hours), duration of analgesia, time to first opioid medication, physical therapy evaluations, time to discharge, and surgeon and patient satisfaction scores.

Inclusion criteria

• Patients undergoing total hip arthroplasty
• Adults 18 years of age and older
• Patients with an American Society of Anesthesiology (ASA) physical status classification of I, II or III

Exclusion criteria

• Patients with ASA physical status classification other than I, II, or III
• Patients with allergies/intolerances to local anesthetic
• Patients with pre-existing neurologic or anatomic deficits in the lower extremity on the side of the surgical site
• Patients with coexisting coagulopathy
• Patients that are pharmacologically anticoagulated will be excluded if placement of peripheral nerve block would be contraindicated according to ASRA (American Society for Regional Anesthesia) guidelines or if spinal anesthesia would be contraindicated according to guidelines