Transversus abdominis plane block for abdominal surgery.

Interest in techniques and applications of the transversus abdominis plane (TAP) block has expanded exponentially since its introduction over ten years ago. The choice of techniques and approaches has been assisted with the availability of ultrasound, but the optimal injection for certain surgical incisions are not yet clear. A literature search was performed looking at anatomical and distribution studies, and clinical trials evaluating the effects of TAP blocks in patients undergoing abdominal surgery. Case reports were also included. Clinical and contrast studies indicate that the landmark and ultrasound guided TAP blocks differ in their spread and mode of action. Regardless, both techniques provide effective analgesia for abdominal surgery. Further research is required to compare TAP blocks with epidural analgesia.

Studies on the spread of local anaesthetic solution in transversus abdominis plane blocks.

The extent of analgesia provided by transversus abdominis plane blocks depends upon the site of injection and pattern of spread within the plane. There are currently a number of ultrasound-guided approaches in use, including an anterior oblique-subcostal approach, a mid-axillary approach and a more recently proposed posterior approach. We wished to determine whether the site of injection of local anaesthetic into the transversus abdominis plane affects the spread of the local anaesthetic within that plane, by studying the spread of a local anaesthetic and contrast solution in four groups of volunteers. The first group underwent the classical landmark-based transversus abdominis plane block whereby two different volumes of injectate were studied: 0.3 ml.kg(-1) vs 0.6 ml.kg(-1). The second group underwent transversus abdominis plane block using the anterior subcostal approach. The third group underwent transversus abdominis plane block using the mid-axillary approach. The fourth group underwent transversus abdominis plane block using the posterior approach, in which local anaesthetic was deposited close to the antero-lateral border of the quadratus lumborum. All volunteers subsequently underwent magnetic resonance imaging at 1, 2 and 4 h following each block to determine the spread of local anaesthetic over time. The studies demonstrated that the anterior subcostal and mid-axillary ultrasound approaches resulted in a predominantly anterior spread of the contrast solution within the transversus abdominis plane and relatively little posterior spread. There was no spread to the paravertebral space with the anterior subcostal approach. The mid-axillary transversus abdominis plane block gave faint contrast enhancement in the paravertebral space at T12-L2. In contrast, the posterior approaches, using both landmark and ultrasound identifications, resulted in predominantly posterior spread of contrast around the quadratus lumborum to the paravertebral space from T5 to L1 vertebral levels. We concluded that the pattern of spread of local anaesthetic differs depending on the site of injection into the transversus abdominis plane. This may have important implications for the extent of analgesia produced with each approach.

Stellate ganglion blockade for analgesia following upper limb surgery.

We report the successful use of a stellate ganglion block as part of a multi-modal postoperative analgesic regimen. Four patients scheduled for orthopaedic surgery following upper limb trauma underwent blockade of the stellate ganglion pre-operatively under ultrasound guidance. Patients reported excellent postoperative analgesia, with postoperative VAS pain scores between 0 and 2, and consumption of morphine in the first 24 h ranging from 0 to 14 mg. While these are preliminary findings, and must be confirmed in a clinical trial, they highlight the potential for stellate ganglion blockade to provide analgesia following major upper limb surgery.

Trunk blocks for abdominal surgery.

In this review, we discuss the central non-neuraxial regional anaesthesia blocks of the abdomen, including intercostal and intrapleural blocks, rectus sheath and ilioinguinal-iliohypogastric blocks, transversus abdominis plane blocks and paravertebral blocks.