Quadrus Lumborum Block (QL Block) Overview

Purpose

• Provides pain control for abdominal and other procedures.
• Involves blockade of intercostal nerves of the abdominal wall.

Anatomy

• Quadrus Lumborum (QL) Muscle
  • Stretches from the iliac crest to the 12th rib.
  • Medial attachments to lumbar transverse processes.
  • Located anterior to erector spinae muscle and posterior to psoas major muscle.
• Nerve Pathway
  • Ventral rami of lower thoracic nerves run along the anterior surface of QL.
  • Local anesthetic placed between psoas and QL anesthetizes these nerves.

Technique

• Cross-Section Anatomy
  • Muscles: transversus abdominus, internal and external oblique, and latissimus dorsi.
  • Structures: erector spinae, QL muscle, and psoas major muscle.
• Nerve Blocking Approaches
  • Lateral Approach: Similar to a TAP block at the lateral aspect of QL.
  • Posterior Approach: Targets fascial plane posterior to QL.
  • Anterior Approach: Targets intermuscular fascial plane between QL and psoas major.

Anterior Approach Preference

• Favored for extensive spread and best effect in abdominal surgery.
• Alternative names: QL3, Transmuscular QL Block.
• Effective due to local anesthetic traveling to the paravertebral space of the lower thorax.

Volume and Effect

• Administration: 30 mL of dilute local anesthetic per side.
• Coverage: Sensory block of anterior and lateral abdominal wall, some visceral coverage.
• Use Cases: Colorectal surgery, cesarean delivery, prostatectomy, nephrectomy, GYN procedures, robotic surgery, potentially hip surgery.

Procedure Positioning

• Can be performed in sitting, prone, or lateral positions.
• Commonly done in lateral position.

Sonographic Guidance

• Probe Placement: Postero-lateral abdomen at iliac crest level.
• Needle Advancement: From posterior or medial side of probe.
• Sonographic Image: QL muscle looks like a flag extending from transverse process.

Tips for Success

• Use imaging of transverse process to identify QL.
• Avoid bony structures in needle path by shifting.
• Use nerve stimulation to avoid SE muscle penetration.
  • Watch for muscle twitching to ensure correct needle path.
• Anterior scanning can help identify QL muscle in challenging patients.

Potential Complications

• Quadriceps weakness due to lumbar plexus block from anesthetic within psoas major.
• Ensure proper needle position to avoid complications.

Conclusion

• QL block is effective for a wide range of abdominal procedures.
• Proper technique and sonographic guidance are critical for effective nerve blockade.