Lumbar Plexus vs Quadratus Lumborum Block in Post-operative Pain Following Total Hip Replacement

Patient will be positioned in lateral decubitus position with side to be blocked facing upwards. Midline will be identified by palpating the spinous process. Intercristal line will be drawn connecting iliac crests. The point of needle insertion will be 4 cm lateral to the intersection of both lines. The transverse process will first contact with a finder needle. Subsequently an 18 gauge 10 cm insulated needle will be used and advanced until it contacted the transverse process. Needle will then be redirected cephalad or caudad and advanced 2 cm, until the quadriceps femoris twitch is obtained. Local anesthetic will then be injected after confirming a motor response between 0.3-0.5 milli amperes.

Patient will be placed in a lateral position with the side to be blocked facing up. A low frequency transducer will be used to identify three layers of abdominal musculature, probe will be then moved posteriorly till the transverse abdominus aponeurosis is visualized, the QL muscle is then identified by tracing the aponeurosis posteriorly. The transducer is then moved more posteriorly to visualize the shadow of transverse process and the origin of QL muscle. Psoas muscle is then identified lying anterior to the QL muscle. A 22 gauge 8 cm is inserted in plane posterior to the probe and advanced intramuscularly through the QL to interfacial plane between QL and psoas major and local anesthetic is deposited.

0.5% ropivacaine 20 ml (100 mg) will be injected for both groups.