Quadratus Lumborum Block for Postoperative Pain Control in Patients Undergoing Unilateral Inguinal Hernia Repair, a Comparative Study Between Two Approaches

A significant component of pain experienced after abdominal surgery is related to incision of the abdominal wall and adequate analgesia can be a challenge.

The ultrasound-guided (USG) quadratus lumborum block QLB was first described by Rafael Blanco in a presentation at ESRA 2007 at the XXVI Annual ESRA Congress in Valencia, Spain. Blanco described a potential space posterior to the abdominal wall muscles and lateral to the quadratus lumborum muscle where Local anesthetics can be injected. This technique provide analgesia after abdominal surgery due to spread of LA from its lumbar deposition cranially into the thoracic paravertebral space where lateral and anterior cutaneous branches from Th7 to L1 can be blocked . This was proved by Carney et al. who found traces of contrast agent in the TPVS following application of this block A novel USG QL block is the transmuscular approach which relies on clearly identifiable sonographic bony landmarks, Where the needle is advanced through the QL muscle, penetrating the ventral proper fascia of the QL muscle and LA is finally injected between the QL and Psoas major (PM) muscle. The transmuscular QL block does not result in redundant antero-lateral spread of the injectate. This may indicate that lower volumes of LA potentially can be used and yet provide extensive thoracolumbar anesthesia.

This study was designed to compare the duration of analgesia provided by the original QLB and transmuscular QLB in patients undergoing surgical repair of unilateral inguinal hernia.