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Chapter 33. Ultrasound-Guided Transversus Abdominis Plane and Quadratus Lumborum Blocks

Which of the following is the most important advantage of quadratus lumborum block (QLB) compared to lateral transversus abdominis plane (TAP) block?

A. Suitable for operations below the umbilicus

B. Smaller volumes of local anesthetics required

C. Wider dermatomal coverage (T7 to L1)

D. Safer in patients on anticoagulant medications

E. Lower incidence of complications

C is correct. The QLB produces a more extensive spread of local anesthetic. QLB results in a wider sensory blockade compared to TAP block (T7–L1 for QLB vs. T10–T12 for the lateral TAP block).

A, B, D, and E are incorrect. Ultrasound-guided TAP blocks are not able to produce a sensory level above the umbilicus consistently unless you add a subcostal injection. Ultrasound-guided QLB has been introduced and shown to result in consistent coverage of at least T8 rostral, and L1 caudally. Moreover, QLB has the potential to provide some visceral analgesia considering its potential spread to paravertebral space especially with the anterior approach.

In this image (Figure 33–1) from the lateral abdominal and lumbar paravertebral area, what is the area labeled “1”?

Figure 33–1

Image from lateral abdominal and lumbar paravertebral area.

(Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2014-2018. All Rights Reserved.)

A. Quadratus lumborum muscle

B. Psoas major muscle

C. Transversus abdominis muscle

D. Spinal nerve

E. Middle thoracolumbar fascia

The answer is: B. Psoas major muscle. See Answer Figure 33–1 for locations of QL muscle, psoas major muscle, transversus abdominis muscle, spinal nerve, and middle thoracolumbar fascia.

Answer Figure 33–1

Image showing location of items A–E from Question 2.

(Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2014-2018. All Rights Reserved.)

In this image (Figure 33–1) from the lateral abdominal and lumbar paravertebral area, what is the area labeled “2”?

Figure 33–1

Image from lateral abdominal and lumbar paravertebral area.

(Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2014-2018. All Rights Reserved.)

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