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

Overview

The Lumbar Plexus (LP) block is currently used as the standard-of-care regional anesthesia technique to provide postoperative pain management after primary hip replacement surgery at UPMC Shadyside Hospital. However, the LP technique is complex and can be associated with potentially serious side effects, including nerve injury, major bleeding, retroperitoneal hematoma, and intrathecal injection of local anesthetic. In rare instances the LP block can also lead to motor blockade, interfering with early ambulation. There are several case reports of Quadratus Lumborum inter-fascial block (QL3) giving equally adequate pain relief after total hip replacement surgery, and this QL3 block is performed routinely at this institution. The benefits to inter-fascial administration of local anesthetic include the avoidance of theoretical nerve injury, bleeding and intrathecal anesthetic administration associated with the direct interaction between the nerve and the nerve block needle. The purpose of this study is to show that QL3 block is non-inferior to the standard-of-care lumbar plexus block and should be used more regularly in hip replacement surgery. The study will be conducted as a prospective, randomized (1:1), double-blind, non-inferiority, active-comparator trial. The investigators plan to enroll 40 subjects, 20 in each treatment group. This study will prospectively investigate the efficacy of QL3 versus Classic LP block for post-operative pain management in subjects undergoing primary, unilateral hip replacement surgery and prospectively compare QL3 versus Classic LP block in time to mobilization and physical therapy response. Primary outcome measures include pain at rest and with movement at 6, 12 and 24 hours after surgery. Secondary outcomes will be time for first request for pain medication, total pain medications (narcotics and non-narcotic analgesics) given in 24 hours and the time of participant's ability to walk 100 feet as recorded by a physical therapist.

Eligible patients will be approached for the study by the PI or Sub-I in the pre-operative area on their day of surgery. The anesthesiology investigator will speak with the patient about the study behind a closed drape and the patient will have adequate time to consider the consent and ask questions regarding risk factors associated with each type of block. Once consented, the patient will be randomized by computer generated random number to one of the two treatment groups. Once assigned the treatment allocation, only the clinician administering the block will be unblinded to the randomization outcome. If randomized to the LP block, an anesthesiologist on the Acute Interventional Perioperative Pain Service (AIPPS) will administer the block with this approach: 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 1 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.If randomized to the QL3 block, an anesthesiologist on the Acute Interventional Perioperative Pain Service (AIPPS) will administer the block with this approach: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. For both treatment groups, the local anesthetic used will be 100 mg 0.5% ropivacaine. After surgery, the patient will be followed by the blinded research team for incidence of adverse events, as well as the collection of the primary outcome measures. These include pain at rest and with movement at 6, 12 and 24 hours after surgery, time for first request for pain medication, total pain medications (narcotics and non-narcotic analgesics) given in 24 hours and the time of participant's ability to walk 100 feet as recorded by physical therapist. This information will be captured from the patient's electronic medical record. Minor changes were made to the outcome measures after the original approval of this submission. This was only to clarify the specific measures from the more general descriptions in the original.