This document provides information on transversus abdominis plane (TAP) blocks, including: - TAP blocks are used for lower abdominal surgeries like appendectomies or cesarean sections by blocking nerves between abdominal wall muscles. - The technique involves using ultrasound to guide a needle between the internal oblique and transversus abdominis muscles, then injecting local anesthetic to expand the plane. - Proper needle placement is confirmed by visualizing expansion of the tissue plane under ultrasound. Local anesthetic spreads anesthesia from T8 to the pubic symphysis. - Catheters can be inserted for continuous infusion if prolonged postoperative analgesia is needed.

1. Radhwan Hazem Alkhashab
Consultant anaesthesia & ICU
2022
TAP block

2. Introduction
Abdominal field blocks have been extensively used for a variety of surgical
procedures for many years. They are simple to perform and have a good
safety profile.
Technique that provides analgesia to the parietal peritoneum as well as the
skin and muscles of the anterior abdominal wall.

3. Indication of TAP block
This block is indicated for any lower abdominal surgery including
1. A unilateral block is used for a one-sided procedure, such as appendectomy,
cholecystectomy, nephrectomy, and renal transplant.
2. Bilateral blocks are used for midline and transverse abdominal incisions, such as
ventral hernia repair, umbilical hernia repair, exploratory laparotomies, colostomy
closures, cesarean delivery, hysterectomy, radical retropubic prostatectomy,
bariatric surgeries, inguinal hernia repair, and laparoscopic surgeries.

4. Anatomy
Innervation of the anterolateral abdominal wall arises
from the anterior rami of spinal nerves T7 to L1. These
include the intercostal nerves (T7-T11), the subcostal
nerve (T12), and the iliohypogastric and ilioinguinal nerves
(L1).
The anterior divisions of T7-T11 continue from the
intercostal space to enter the abdominal wall between the
internal oblique and transversus abdominis muscles until
they reach the rectus abdominis, which they perforate
and supply, ending as anterior cutaneous branches
supplying the skin of the front of the abdomen.

5. Midway in their course they pierce the external
oblique muscle giving off the lateral cutaneous
branch which divides into anterior and posterior
branches that supply the external oblique muscle
and latissmus dorsi respectively.
The iliohypogastric nerve (L1) divides between
the internal oblique and transversus abdominis
near the iliac crest into lateral and anterior
cutaneous branches, the former supplying part
of the skin of the gluteal region while the latter
supplies the hypogastric region.

6. The ilioinguinal nerve (L1) communicates with the
iliohypogastric nerve between the internal oblique
and transversus abdominis near the anterior part of
the iliac crest. It supplies the upper and medial part
of the thigh and part of the skin covering the
genitalia.
The transversus abdominis is the deepest layer,
and below is the peritoneum. The skin, muscles,
and peritoneum of the anterior abdominal wall are
innervated by the lower 6 thoracic nerves and the
first intercostals nerve.

7. TAP us view

8. Technique
 Patient Position: Supine.
 Probe: Ultrasound machine with a linear
transducer. (Sometimes a curvilinear transducer
might be needed, if the patient is obese or if
performing a posterior approach)
 Probe Position: Transverse or transverse oblique
between the margin of the 12th rib and superior
iliac spine.
 Needle: 22-gauge blunt needle (5-10 cm) for
single injection. 18-gauge Tuohy needle (5-10 cm)
for continuous infusions.
 Local Anesthetic: Bupivaciane 0.25% (20-30 mL),
ropivacaine 0.2% (20-30 mL).

9. Technique:
 This block may be performed before or following induction of general or spinal anesthesia.
 The patient needs to be lying supine.
 An aseptic technique is advocated using a no- touch technique, an appropriate cleaning
solution, and a sterile cover for the ultrasound probe.
 The ultrasound probe is positioned horizontally on the skin just above the iliac crest in the
midaxillary line.
 The muscle layers are identified. We prefer to use a peripheral nerve block needle because it
allows "distant" injection by your assistant while you remain in control of ultrasound probe
and needle.
 A 50-mm needle is usually sufficient.
 We use an in-plane approach inserting the needle posteriorly and directing anteriorly.
 The needle is followed under direct vision as it passes through the muscle layers.
 Tip lies between the internal oblique and transversus abdomenus muscles.

10. Ultrasound- guided TAP The ultrasound probe is placed in a transverse plane to the
lateral abdominal wall in the midaxillary line, between the lower costal margin and iliac
crest.
The needle is introduced in plane of the ultrasound probe directly under the probe
and advanced until it reaches the plane between the internal oblique and transversus
abdominis muscles.
Upon reaching the plane, 2 ml of saline is injected to confirm correct needle position
after which 20 ml of local anaesthetic solution is injected. The transversus abdominis
plane is visualized expanding with the injection ( appears as a hypoechoic space).

11. Injection of the local anesthetic must be seen to ensure correct placement.
It is very characteristic to see the layer expanding in an ellipsoid way.
We use of 20 mL of 0.5% ropivacaine resulting in a block from T8 to the symphysis
pubis.

12. If prolonged analgesia is required beyond the duration of a single shot of local
anaesthetic , a catheter can be introduced into the transversus abdominis plane
through a touhy needle. After opening up the plane with 2 ml of saline, the catheter is
introduced around 3 cm beyond the needle tip. . Position is verified by injecting the
local anaesthetic bolus (20ml). An infusion of a dilute local anaesthetic is started at a
rate of 7 to 10 ml per hour.

13. TAP needling

14. The End
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