Transverse abdominis plane block: Evolution and current understanding

Regional blockade of the anterior abdominal wall can contribute significantly to postoperative analgesia for a wide range of abdominal and pelvic procedures, as part of a multimodal analgesic regime. Abdominal wall blocks are not new in the field of anaesthesia but they have gained in popularity recently with the widespread adoption of ultrasound guided regional anaesthesia. In this chapter we describe the evolution of the transverse abdominis plane block, with reference to its anatomy, sonoanatomy and the progression from landmark to ultrasound-guided techniques. The quadratus lumborum block developed as a consequence of the move from anterior to posterior in transverse abdominis plane blocks and the approaches used for this are described. We detail the evidence for the analgesic effi cacy of these blocks compared to other modes of analgesia and also discuss areas of ongoing interest in the fi eld. Finally, we describe its use in special patient populations as well as reported complications.