Skip to Main Content


Ultrasound scanning (US) can offer several advantages when used to guide placement of the needle for centroneuraxial blocks (CNBs). It is noninvasive, safe, simple to use, can be performed expeditiously, provides real-time images, is devoid from adverse effects, and it may be beneficial in patients with abnormal or variant spinal anatomy. When used for chronic pain interventions, US also eliminates or reduces exposure to radiation. In expert hands, the use of US for epidural needle insertion was shown to reduce the number of puncture attempts,1–4 improve the success rate of epidural access on the first attempt,2 reduce the need to puncture multiple levels,2–4 and improve patient comfort during the procedure.3 These advantages led the National Institute of Clinical Excellence (NICE) in the United Kingdom to recommend the routine use of ultrasound for epidural blocks.5 Incorporating these recommendations into clinical practice, however, has met significant obstacles. As one example, a recent survey of anesthesiologists in the United Kingdom showed that >90% of respondents were not trained in the use of US to image the epidural space.6 In this chapter, we describe techniques of US imaging of the spine, the relevant sonoanatomy, and practical considerations for using US-guided CNB and nerve blocks close to the centroneuroaxis.


Bogin and Stulin were probably the first to report using US for central neuraxial interventional procedures.7 In 1971, they described using US to perform lumbar puncture.7 Porter and colleagues, in 1978, used US to image the lumbar spine and measure the diameter of the spinal canal in diagnostic radiology.8 Cork and colleagues were the first group of anesthesiologists to use US to locate the landmarks relevant for epidural anesthesia.9 Thereafter, US was used mostly to preview the spinal anatomy and measure the distances from the skin to the lamina and epidural space before epidural puncture.10,11 More recently, Grau and coworkers, from Heidelberg in Germany, conducted a series of studies, significantly contributing to the current understanding of spinal sonography.1–4,12–15 These investigators described a two-operator technique consisting of real-time US visualization of neuraxial space using a paramedian sagittal axis and insertion of the needle through the midline to accomplish a combined spinal-epidural block.4 The quality of the US image at the time, however, was substantially inferior to that of today's equipment, thus hindering acceptance and further research in this area. Recent improvements in US technology and image clarity have allowed for much greater clarity during imaging of the spine and neuraxial structures.16,17


Basic Considerations


Because the spine is located at a depth, US imaging of the spine typically requires the use of low-frequency ultrasound (5-2 MHz) and curved array transducers. Low-frequency US provides good penetration but unfortunately, it lacks the spatial resolution at the depth (5–7 cm) at which the neuraxial structures are located. The osseous framework of the spine, which envelops the neuraxial structures, reflects much of ...

Want remote access to your institution's subscription?

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.


About MyAccess

If your institution subscribes to this resource, and you don't have a MyAccess profile, please contact your library's reference desk for information on how to gain access to this resource from off-campus.

Subscription Options

AccessAnesthesiology Full Site: One-Year Subscription

Connect to the full suite of AccessAnesthesiology content and resources including procedural videos, interactive self-assessment, real-life cases, 20+ textbooks, and more

$995 USD
Buy Now

Pay Per View: Timed Access to all of AccessAnesthesiology

24 Hour Subscription $34.95

Buy Now

48 Hour Subscription $54.95

Buy Now

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.