Abdominal field block.pdf

For anesthesia care providers.

1. BY: Kanbiro G. (BSC, MSC in ACA)
[email protected]
College of Medicine and Health science

Department of Anesthesia
Abdominal Field Block
2015/2023

2. Outline:

Introduction

Anatomy

Clinical use

Indication and contraindication

Techniques

Complications
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3. Introduction

Regional blocks of the anterior abdominal wall can
significantly help with intraoperative and postoperative
analgesia for abdominal surgical pain.


Abdominal wall nerve blocks includes the ilioinguinal,
iliohypogastric, rectus sheath, and transversus
abdominis plane (TAP) blocks
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4. Anatomy

Anterior abdominal wall: Its is the area surrounded:

Superiorly: by costal margin and xiphoid process

Inferiorly: by inguinal ligament and pelvic bone

Laterally: by mid-axillary line.
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5. Anatomy: Layers…..

Layers of Anterior abdominal wall: superficial to
deep

Skin,

Subcutaneous tissue

External Oblique muscle (EO)

Internal Oblique muscle (IO)

Transversus abdominis muscle (TA)

Extra peritoneal fat and Parietal peritoneum.
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6. Anatomy: Layers…..
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7. Anatomy: Layers….

External oblique muscle (EO):

It is the superficial layer

Originating from mid and lower ribs

Fibers sloping forward and downward to the iliac
crest.

Forming an aponeurosis below that level.

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8. Anatomy: Layers….

Internal Oblique muscle (IO):

Attaches to the lateral two-thirds of the inguinal
ligament and anterior iliac crest

Fibers sloping forwards and upwards.


Transversus abdominis muscle (TA):

The innermost layer

Fibers running transverse towards the midline.
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9. Anatomy: Layers….

Rectus abdominis muscle:

This paired muscle is lying medially and separated
in the midline by the linea alba.


It is wide and thin superiorly, increasing in
thickness inferiorly.


The majority of this muscle is enclosed by the rectus
sheath.
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10. Anatomy: Innervation

The skin, muscles and the parietal peritoneum of the
anterior abdominal wall are innervated by the anterior
rami of (T7–L1) spinal nerves.


This thoracolumbar nerves passes through a fascial
plane which is found in between the IO and TA muscles


At the costal margins the thoracic nerves (T7–T11)
enters the transverse abdominal plane (TAP).
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11. Anatomy: Innervation..
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12. Anatomy: Innervation….

Nerves from T7–T9: supply the skin superior to the
umbilicus.


T10: supply umbilicus.


Nerves from T11, the cutaneous branch of the subcostal
T12, the iliohypogastric nerve, and the ilioinguinal
nerve: supply the skin inferior to the umbilicus.
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13. Anatomy: Innervation….

Classified as:

Intercostal: (T7–T11)

Subcostal: (T12)

Ilioinguinal–iliohypogastric nerves: (L1)
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14. Anatomy: Innervation….

Intercostal nerves: (T7 – T11):

Travel along intercostal space => at the costal margins
enters the transverse abdominal plain (TAP) (b/n
TAM and IOM).

Anterior cutaneous branches=> pierce the RAM

Supplying sensation to the skin of the anterior
abdomen.

Lateral cutaneous branches=> travel posteriorly,
piercing the EOM=>

Supply sensation to the skin of the lateral abdomen and
back.
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15. Anatomy: Innervation….

Subcostal nerve: T12

Runs anteriorly between the TAM and IOM.


Gives a communicating branch to the L1 nerve as part
of the upper part of the lumbar plexus.


The lateral cutaneous branch of T12 supplies the
skin over the upper gluteal region.
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16. Anatomy: Innervation….

The iliohypogastric nerve:

Originates from the L1 nerve root

Supplies the sensory innervations to the skin over the
inguinal region.

Runs in the plane between the IO and TA muscles
(TAP)

Later pierces the IO to lie between IO and the EO
before giving off cutaneous branches.
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17. Anatomy: Innervation….

The ilioinguinal nerve:

Originates from the L1 nerve root.

Found inferior to the iliohypogastric nerve

Perforating the IO muscle at the level of the iliac
crest running medially in a deeper plane than the
iliohypogastric nerve.

Innervates the inguinal hernia sac, medial aspect of
the thigh, anterior scrotum and labia.

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18. Anatomy: Innervation….
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19. Clinical use

Regional analgesia of the abdominal wall can provide
good analgesia for a variety of surgical operations
especially when used as part of a multimodal
technique.


Hemodynamics effects are minimal as spread of local
anesthetic is limited to the abdominal wall=> not block
sympathetic nerve


Have role in decreasing analgesic requirements

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20. Clinical use..

Blocks only provide analgesia of the abdominal wall, not
to the abdominal viscera=> systemic analgesia
required.


Useful in ambulatory surgery to improve the quality
of analgesia and to reduce postoperative opioid
requirements.

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21. Clinical use..

Obesity may make both the landmark and ultrasound
approaches more challenging.


These blocks are most commonly performed as a ‘single
shot’ technique.


Catheter techniques are also possible when more
prolonged analgesia is required but are not currently in
widespread use.
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22. Clinical use..
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23. TAP Block

24. TAP Block: Introduction

It is a volume block by placing a large volume of local
anaesthetic in the fascial plane between the IO and
TA which contains the nerves from T7 to L1.


Aim to block the sensory nerves of the anterior
abdominal wall before they pierce the musculature to
innervate the anterior abdomen.


Onset taking up to 30-60 min to reach maximal effect.


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25. TAP Block: Introduction..

Indications:

Used as part of an analgesic regimen for surgery on the
lower abdomen, for example:

Hernia repair

Open appendectomy

Caesarian section

Total abdominal hysterectomy

Radical prostatectomy
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26. TAP Block: Introduction..

Contraindications:

Absolute:

Patient refusal

Allergy to local anesthetic

Localised infection over injection point

Relative:

Coagulopathy

Surgery at injection site
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27. TAP Block: Technique

The Approaches include:

Blind technique: based on surface anatomy landmarks.


Ultrasound guided technique: performed under direct
vision

Lateral TAP

Posterior TAP

Anterior TAP

Subcostal/Oblique TAP
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28. TAP Block: Technique..

Landmark technique:

The TAP is accessed from the lumbar ‘triangle of
Petit’, bounded:

Anteriorly by: the EO,

Posteriorly by: the lattisimus dorsi, and

Inferiorly by: the iliac crest.


A cadaveric anatomical study has noted a large
variability in the position of the ‘triangle of Petit’ and
can be difficult in the obese patient.
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29. TAP Block: Technique..
‘triangle of Petit’
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30. TAP Block: Technique..

General Preparation:

Full resuscitation equipment

Patient monitoring (ECG, pulse oximeter, BP)

Antiseptic skin preparation and sterile gloves

Short bevel (30o ) block/blunted needle (50–100 mm), or
16-G Tuohy needle, with an extension set

20 ml syringes
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31. TAP Block: Technique..

Local anaesthetic: long acting local anaesthetic:
Bupivacaine, Levobupivacaine, Ropivacaine….

Large volume of LA: at least 20 ml of solution for each
side or 0.3-0.6 ml/kg per side.

The concentration of solution used will depend on
the calculated maximum dose of local anaesthetic
allowed.


The blocks can be performed awake but are most
commonly performed with the patient under general
anaesthetic.

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32. TAP Block: Technique..

Landmark

Identify the triangle of petit just by a surface
landmark bound by the external oblique muscle
anteriorly, the latissimus dorsi muscle posteriorly and
the iliac crest inferiorly.


Normally found in the region of the posterior axillary
line, directly above the iliac crest.
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33. TAP Block: Technique..
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34. TAP Block: Technique..

Injection:

Insert the blunt tipped short bevel regional block
needle perpendicular to the skin.


After piercing the skin=> the needle is advanced until a
‘pop’ is felt’ (the needle piercing the fascial extension
of the external oblique muscle).


The needle should be advanced until a second ’pop’ is
felt’ (the needle passes through the fascial extension
of the internal oblique muscle).
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35. TAP Block: Technique..

The needle should lie superficial to the transversus
abdominis muscle (in the transversus abdominis
plane).


After aspiration, a minimum of 20 ml of local anaesthetic
per side is injected.


Be careful not to exceed the maximum safe dose of local
anaesthetic
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36. TAP Block: Technique..
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37. TAP Block: Technique..

For incisions at or crossing the midline, a bilateral TAP
block is indicated.


Ultrasound can also be used to identify the muscle layers
and ensure accurate placement of local anaesthetic.
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38. TAP Block: Technique..

Advantage:

Provides analgesia for the abdominal wall and used as
part of a multimodal approach to analgesia.

Less risk of systemic side-effects.

Good postoperative analgesia and a decrease in
morphine requirements for up to 48 h.


Used for a variety of surgeries including open
colorectal surgery, retropubic prostatectomy,
abdominal hysterectomy, and Caesarean section.
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39. TAP Block: Technique..

Limitation:

It does not provide analgesia for visceral contents.

Limited analgesic effect for incisions above the umbilicus.

Difficult in obese patients.
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40. TAP Block: Complications

Complications:

It is a relatively safe technique with only a few case
reports of significant complications.

Complications reported include:

Failure

Local anaesthetic toxicity

Intraperitoneal injection

Bowel injury

Hepatic injury
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41. Rectus Sheath Block

42. Rectus Sheath Block: Introduction

It is used for analgesia after umbilical or incisional
hernia repairs and other midline surgical incisions.


The aim of this technique is to block the terminal
branches of the 9th 10th, and 11th intercostal
nerves=>


Which run in between the IO and TA muscles to
penetrate the posterior wall of the rectus abdominis
muscle=> end in an anterior cutaneous branch
supplying the skin of the umbilical area.
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43. Rectus Sheath Block: Introduction..
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44. Rectus Sheath Block: Technique

The approach: Blind technique or Ultrasound-
Guided


Passing the needle through anterior rectus sheath
and through the rectus abdominis muscle=>


Injecting the local anaesthetic on the posterior wall of
the rectus sheath.


Local anesthetic spread between rectus muscle and
posterior rectus sheath.
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45. Rectus Sheath Block: Technique..

Landmark:

The patient lying supine, a point is identified 2–3 cm
from midline


Slightly cephalad to the umbilicus at the apex of bulge
of the rectus abdominis muscle.
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46. Rectus Sheath Block: Technique..
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47. Rectus Sheath Block: Technique..

Injection:

A short- beveled 5 cm needle, directed at right angles
to the skin=>


Initially passed through the skin until the resistance of
the anterior sheath can be felt=>


A definitive ‘pop’ should be felt=>
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48. Rectus Sheath Block: Technique..

The needle is advanced further until the firm resistance
of the posterior wall is felt( scratch )=>


Injection of 10–20 ml local anaesthetic per side or 0.1
mL/kg per side (children).


The procedure is repeated on the opposite side of the
midline.

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49. Rectus Sheath Block: Technique..
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50. Rectus Sheath Block: Complication

The posterior wall of the rectus sheath lying superficial
to the peritoneal cavity=>


Needle misplacement may lead to complications:

Injection into the peritoneal cavity will lead to failure
of the block and

May risk bowel perforation or puncture of blood
vessels, usually the inferior epigastric vessels
.
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51. Rectus Sheath Block: Complication..

In addition to incorrect placement of local anaesthetic,


Incomplete block may result from anatomical
variance, as in up to 30% of the population,
o
The anterior cutaneous branch of the nerves are
formed before the rectus sheath and
o
Do not penetrate the posterior wall of the rectus
sheath

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52. Ilioinguinal-iliohypogastric
nerve blocks

53. IIH Nerve Block: Introduction

Inguinal herniorrhaphy pain can be significant and
difficult to treat without opioid analgesics,

But blocking the iliohypogastric and ilioinguinal
nerves can provide good analgesia for most operations
in the inguinal region.


The blocks may be very effective in reducing the need for
opioids.


In pediatric patients, they have been found to be as
effective as caudal blocks, even though a higher
failure rate.

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54. IIH Nerve Block: Introduction..

Indications:

Anesthesia and postoperative analgesia for inguinal
hernia repair and other inguinal surgery;


Analgesia following suprapubic incision
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55. IIH Nerve Block: Technique

The classical approach uses a landmark technique
which blocks the nerves once they have separated into
the different facial layers.


Landmark:

Injection site is at a point 2 cm medial and 2 cm
cephalad to the anterior superior iliac spine (ASIS)


Use a short-bevelled needle advanced perpendicular to
the skin.
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56. IIH Nerve Block: Technique..
Landmark:
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57. IIH Nerve Block: Technique..

After an initial pop sensation as the needle penetrates
the external oblique aponeurosis=>

Around 5-8ml of local anaesthetic is injected or 0.15
mL/kg per side to block ilioinguinal nerve.


The needle is then inserted deeper until a second pop is
felt penetrating the internal oblique aponeurosis=>

Further 5-8ml of local anaesthetic is injected to block
the iliohypogastric nerve
.
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58. IIH Nerve Block: Technique..

A fan-wise subcutaneous injection of 3– 5 ml can be
made

To block any remaining sensory supply from the
intercostals and subcostal nerve.


This approach has a success rate of 70% with failure
often due to the local anaesthetic being placed more than
one anatomical layer away from the nerves.
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59. IIH Nerve Block: Technique..

If used as the sole technique for inguinal
herniorrhaphy:

The sac containing the peritoneum should be
infiltrated with local anaesthetic by the surgeon as it
is supplied by the abdominal visceral nerves.
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60. IIH Nerve Block: Complications

The placement of the needle and local anaesthetic too
deep may result in:

Block failure and inadvertent femoral nerve block.


Injection into the peritoneal cavity will lead to:

Failure of the block and may risk bowel perforation.


Puncture of blood vessels, usually the inferior
epigastric vessels.


The use of ultrasound guidance may potentially reduce
the incidence of these complications
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61. THANK YOU!!!