Trunk AnesthesiaPart 1: Anterior Approach

Andrew Gray, M.D., Ph.D.San Francisco General HospitalSan Francisco, CA

Disclosure

The presenter receives royalties from medical publications.

Lecture Objective

For the target audience to:

• 1. Describe the ultrasound anatomy of the anterior abdominal wall for regional blocks.

• 2. Be able to identify adverse events and artifacts that can occur during these ultrasound guided regional anesthetics.

Anterior Abdominal Wall

1. Transversus Abdominis Plane (TAP)2. Ilioinguinal Nerve Blocks (ILIH)3. Rectus Sheath Blocks (RSB)

Anterior Abdominal Wall

1. Transversus Abdominis Plane (TAP)2. Ilioinguinal Nerve Blocks (ILIH)3. Rectus Sheath Blocks (RSB)

Transversus Abdominis Plane (TAP)

Clinical Trial ReferenceCesarean Delivery Multiple

Open Prostatectomy O’Donnell et al., 2006

Total Abdominal Hysterectomy

Carney et al., 2008

Open Appendectomy Niraj et al., 2009

Iliac Crest Bone Graft Chiono et al., 2010

Open Inguinal Hernia Repair Aveline et al., 2010

TAP Nerves

TAP Nerves

EO

IO

TA

TAP Nerves

TAP Nerves

EOIOTA

Medial

Transversus Abdominis Plane (TAP)

Transversus Abdominis Plane (TAP)

EO

IOTA

Posterior

Transversus Abdominis Plane (TAP)

Transversus Abdominis Plane (TAP)

EO

IO

TA

Posterior

Transversus Abdominis Plane (TAP)

Rozen, W.M. et al., Clin Anat 2008;21:325-33

“The optimal plane for infiltration of anesthetic is between this fascial layer and the transversusabdominis muscle layer.”

“A fascial layer between the internal oblique and transversus abdominis muscles required elevation to expose the neurovascular structures on its deep surface.”

Transversalis Fascia (TF) Block

Transversalis Fascia (TF) Block

LA

EO

IO

TA

Posterior

Transversus Abdominis Plane (TAP)

Anatomic Structure Sonography Reference

External Oblique Often Hyperechoic Hebbard 2007

Internal Oblique Thickest Muscle Rankin 2006

Transversus Abdominis Thinnest MuscleHypoechoic

Rankin 2006Hebbard 2010

Retroperitoneal Fat Fibro-fatty Echoes Gore 1982

Quadratus Lumborum Hypoechoic Callen 1979

Peritoneum Very HyperechoicComet-Tail ArtifactGut Sliding

Hanbidge 2003

Transversus Abdominis Plane (TAP)

Key points:

• 1 Perform TAP block near the posterior corner of the transversus abdominis muscle between the costal margin and iliac crest in the mid-axillary line.

• 2 Extend the injection by advancing the block needle within the TAP.

• 3 These blocks are best used for surgical procedures of the lower abdominal wall as part of multimodal pain management.

Anterior Abdominal Wall

1. Transversus Abdominis Plane (TAP)2. Ilioinguinal Nerve Blocks (ILIH)3. Rectus Sheath Blocks (RSB)

ILIH Nerves

ILIH Nerves

EO

IO

TAIC

A

Medial

Ilioinguinal Nerve Blocks (ILIH)

Ilioinguinal Nerve Blocks (ILIH)

EO

Medial

IO

ICTA

Ilioinguinal Nerve Blocks (ILIH)

Ilioinguinal Nerve Blocks (ILIH)

IC

Medial

Ilioinguinal Nerve Blocks (ILIH)

Key points:

• 1 Best visibility of the ilioinguinal and iliohypogastricnerves is medial to the iliac crest (1 to 2 cm).

• 2 The ilioinguinal nerve is often accompanied by the deep circumflex iliac artery (DCIA).

• 3 These blocks are best used for selective diagnostic purposes.

Anterior Abdominal Wall

1. Transversus Abdominis Plane (TAP)2. Ilioinguinal Nerve Blocks (ILIH)3. Rectus Sheath Blocks (RSB)

Rectus Sheath Block

Rectus Sheath Block

RALA

Medial

Rectus Sheath Block

Rectus Sheath Block

TARA

Medial

Rectus Sheath Block

Rectus Sheath Block

RA RA

CaudadCephalad

Rectus Sheath Block

Rectus Sheath Block

RA RA

LA

CaudadCephalad

Rectus Sheath Blocks (RSB)

Rectus Sheath Blocks (RSB)

RA

Rectus Sheath Blocks (RSB)

Key points:

• 1 Inject between the rectus abdominis muscle and underlying double layer.

• 2 For supraumbilical injections the transversus abdominislies under the lateral corner of the rectus abdominis.

• 3 Bilateral injections are necessary because the linea alba is normally a complete midline barrier.