Usefulness of Shamrock View for Deep Nerve Blocks

Abstract

Ultrasound guided nerve blocks have extremely developed in last one decade. However, Deep nerve blocks using ultrasound assist, especially the lumbar paravertebral region, have had disadvantage about the quality of the image and the artifact caused by bony structures compare with superficial nerve blocks. Recently, a novel approach to lumbar paravertebral region, Shamrock view reported by Sauter et.al., has attracted rising attention. There are several advantages in performing lumbar plexus block and quadratic lumbermen block for perioperative pain management, and lumbar root block and transforaminal epidural block for Interventional pain therapy. “Shamrock” was named from the ultrasound image of three muscle, psoas major muscles, quadratus lumborum muscle, and erector spine muscle, around lumbar transverse process as like three-leafs clover. This scan is superior to the standard posterior scan in the point that acoustic shadow of transverse process does NOT interfere the image of psoas major muscle. The needle visibility is also extremely better because of perpendicular reflection to the needle. Furthermore, structures in the lumbar spinal canal, dura and subarachnoid space, were also visible through the intervertebral foramen using Shamrock view. This provides a lot of information when we perform the lumbar paravertebral block and interventional procedures. We will present Tips of these techniques in our clinical practice.