Ultrasound Guidance for Nerve Blocks: Principles and Practical Implementation
Peter Marhofer, ed Oxford, UK: Oxford University Press, 2008. ISBN 978-0-19-954756-2. 146 pages, $49.95.
“In the land of the blind, the one-eyed man is king.”
For orthopedic surgery involving the upper and lower extremities, as well as many thoraco-abdominal wall procedures, the use of peripheral nerve blocks is an integral part of the anesthesiologist’s armamentarium. In the last few years, ultrasound guidance (USG) for performing peripheral nerve blocks has increased dramatically. The potential benefits of USG for continuous peripheral nerve and neuro-plexus blocks include the ability to directly visualize the neural and perineural anatomy (which is particularly valuable in the setting of anatomical variations). USG for peripheral nerve blocks has been reported to improve the efficiency of single-injection peripheral nerve blocks by decreasing the procedure time, the number of needle passes, the onset time of the sensory blockade, and increasing the overall success rates. There is an increasing need for practicing anesthesiologists to understand the anatomical and ultrasonographic physical principles, as well as both basic and advanced USG techniques, to improve upon their success in performing peripheral nerve blocks.
In this 146 page handbook with 13 chapters and two appendices, Marhofer and his contributors describe the most important USG peripheral nerve blocks. The first chapter is devoted to an “in depth” description of the principles of ultrasound. This chapter provides simplified explanations of the physical basis for the propagation and reflection of ultrasound waves, describes how the various probes function, and explains common artifacts (some of which are also described in Chapter 7). Two chapters are devoted to technical prerequisites and needle guidance, focusing on issues relevant to clinical practice (e.g., technical position of the anesthesiologist, probes and needles, and aseptic con-ditions). However, there is a significant degree of subjectivity in some of the chapters due in part to the technical ex-pertise and vast clinical experience of the contributing authors in using USG techniques. For example, one of the co-authors suggested that use of ultrasound would result in significant cost savings for performing nerve blocks because of the reduced use of insulated nerve stimulating needles.
The two subsequent chapters rely on recent data from peer-reviewed literature in describing the advantages and limitations of using USG to perform peripheral nerve blocks, with references cited at the end of each chapter. However, these authors claim that the use of ultrasound “increases the margin of safety of deep blocks” without providing data from the peer-reviewed literature to support this position. The chapter on sonoanatomy of peripheral nerves and other anatomical structures and their structural relationship is well supported using multiple photographs to illustrate the key aspects of different plexuses and nerves and their visualization in short axis (tranversal) and long axis (longitudinal) views.
Chapters 8–11 followed a logical sequence from cervical (neck) to truncal blocks, including proximal and distal blocks of the upper and lower extremities. The focus of each chapter was on clinical practice, and the authors describe the key anatomical considerations, the recommended USG technique, and a practical approach to performing the block using USG. The descriptions of specific block techniques are easy to read and summarize the important technical aspects, while providing recent data to support their recommendations. At the end of each chapter, a table elegantly describes the degree of expertise required to perform a given block technique (i.e., basic, intermediate, advanced), the necessary equipment (e.g., probe type, ultrasound frequency, and type of needle), the recommended technique (i.e., in plane or out of plane), the ultrasonographic appearance of the nerve structures and the surrounding anatomic environment, and the recommended dose of local anesthetic. High-quality ultrasonic images are used to illustrate the key points. The ultrasound images and descriptions of the puncture techniques for performing peripheral nerve blocks are easily un-derstandable to both novice and the more experienced practitioner. Up-dated references allow the reader to obtain a more in-depth knowledge of the USG block techniques.
The reader should be aware that, although the authors are all highly skilled specialists in regional anesthesia and USG techniques, many of the recommendations are based on the author’s clinical experience rather than rigorously obtained data from peer-reviewed literature. The absence of anatomical or magnetic resonance imaging cross-sectional images (which would facilitate the reader’s understanding of the anatomical aspects of the USG techniques) is regrettable. Some minor deficiencies are (1) use of the interscalene block is regarded as advanced technology in the essentials; (2) CP is labeled cervical plexus in Figure 9.4 rather than cervical pleura (which may be misleading in this area), and (3) a quantity of 5 mL of local anesthetic is considered sufficient for a surgical femoral block. The discussions of catheter techniques and future perspectives in Chapters 12 and 13, respectively, could have been more expansive. For example, the ultrasound technique utilized for introducing catheters should have been described in greater depth. Both the ZUERS Ultrasound Experts Regional Anesthesia Statement (Appendix 1) and the Vienna score (Appendix 2) for USG nerve blocks are excellent additions to the text material. These materials are compatible with the American Society of Regional Anesthesia and the European Society of Regional Anesthesia Joint Committee recommendations for USG regional anesthesia.
The contributors are all world-renowned experts in USG techniques for peripheral nerve blocks. The novice, intermediate, and advanced practitioner using USG for performing peripheral nerve blocks will all benefit from reading this book and improve their technical skills and success rates. This booklet is insightful and useful for practitioners of regional anesthesia. It can be used every day in clinical practice as it is easily carried in one’s pocket. In summary, this handbook is an excellent addition to the peripheral nerve block library of all anesthesiologists interested in advancing their knowledge of regional anesthetic techniques.
Xavier Capdevila, MD, PhD
Department of Anesthesiology and Critical Care Medicine
Lapeyronie University Hospital and Montpellier School of Medicine