Spinal sonography and central neuraxial blocks

Central neuraxial blocks (CNBs), which include spinal, epidural, and combined spinal epidural injections, are indispensable techniques in the anesthesiologist's armamentarium. Indeed, in scenarios such as when dealing with the obstetric population, patients with obesity, or patients having respiratory compromise (e.g., lung disease or scoliosis), CNBs are the mainstay for anesthesia and/or analgesia. Traditionally, CNBs are performed using anatomical landmarks, which are simple, easy to master, and exceptionally successful in most cases. Nevertheless, there are notable limitations with this approach, especially in scenarios where CNBs are considered mandatory and vital. Any limitation of an anatomic landmark-based approach is an opportunity for an ultrasound-guided (USG) technique. This has become particularly true for CNBs, where recent advances in ultrasound technology and research data have addressed many of the shortcomings of the traditional anatomic landmark-based approaches. This article reviews the ultrasound imaging of the lumbosacral spine and its application for CNBs.