Transversus Abdominis Plane Block: An
Highlights
- The transversus abdominis plane (TAP) block was first introduced by Rafi [1] in 2001 as a landmark-guided technique via the triangle of Petit to achieve a field block (View Highlight)
- Since the thoracolumbar nerves originating from the T6 to L1 spinal roots run into this plane and supply sensory nerves to the anterolateral abdominal wall [2], the local anesthetic spread in this plane can block the neural afferents and provide analgesia to the anterolateral abdominal wall. (View Highlight)
(View Highlight)- The thoracolumbar spinal nerves (T6~L1) innervating the anterolateral abdominal wall (View Highlight)
- The thoracolumbar nerves are responsible for the segmental cutaneous supply of the abdominal wall. They divide into the anterior primary ramus and posterior primary ramus shortly after exiting from the intervertebral foramen. The posterior ramus travels backward, while the anterior ramus branches into lateral and anterior cutaneous nerves (View Highlight)
- The anterolateral abdominal wall is mainly innervated by the anterior rami of the thoracolumbar spinal nerves (T6-L1), which become the intercostal (T6-T11), subcostal (T12), and ilioinguinal/iliohypogastric nerves (L1) (Figure 1(a)). These branches further communicate at multiple locations, including large branch communications on the anterolateral abdominal wall (intercostal/upper TAP plexus) and plexuses that run with the deep circumflex iliac artery (DCIA) (lower TAP plexus) and the deep inferior epigastric artery (DIEA) (rectus sheath plexus) [2]. Since these segmental nerves communicate just above the transversus abdominis muscle, the subfascial spread of local anesthetic can provide anterolateral abdominal wall analgesia (View Highlight)
- the lateral cutaneous branch of T12 does not further divide into anterior and posterior branches (Figure 1(b)). It supplies a part of the gluteal region, and some of its filaments extend as low as the greater trochanter (View Highlight)
- The L1 spinal nerve divides into the iliohypogastric and ilioinguinal nerves, which innervate the skin of the gluteal region behind the lateral cutaneous branches of T12, the hypogastric region, the upper medial part of the thigh, and the genital area (View Highlight)
- Since the lateral cutaneous branches leave the TAP posterior to the midaxillary line, posterior injection of local anesthetics is suggested if analgesia for both the anterior and lateral abdominal wall is required (View Highlight)
- most of the lateral cutaneous branches arise before the main nerves enter the TAP, and only those of T11 and T12 have a short course within or through the TAP (View Highlight)
- Paravertebral spread from T5 to L1 has been reported only with posterior TAP blocks (View Highlight)
- The L1 branches, which become the ilioinguinal and iliohypogastric nerves, pass into the TAP near the anterior part of the iliac crest [15]. Thus, a TAP block at this level is similar to ilioinguinal and iliohypogastric nerve blocks. Direct ilioinguinal/iliohypogastric nerve block is a better choice than TAP block if only L1 analgesia is needed (View Highlight)
- The T6-8 supply the area below the xiphoid and parallel to the costal margin; T9-12 supply the periumbilical area and the lateral abdominal wall between the costal margin and iliac crest; L1 supplies the anterior abdomen near the inguinal area and thigh (View Highlight)
- Compared to a lateral TAP block, a posterior TAP block approximates the double-pop TAP technique at the lumbar triangle of Petit [44] by injecting local anesthetic superficial to the transversus abdominis aponeurosis [45] and offers better and more prolonged analgesia than the lateral approach (View Highlight)
- If the transducer is placed posteriorly, we find that internal oblique and transversus abdominis taper off into a common aponeurosis, also called the thoracolumbar fascia, which is connected to the lateral border of the quadratus lumborum (View Highlight)