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Ultrasound imaging technology has become prevalent and easily accessible to the pain physician. In the past 20 years, there has been a significant increase in the use of ultrasound-guided pain procedures to the point that even procedures once relegated to fluoroscopic approaches are now able to be done sufficiently with ultrasound techniques. The advancement of ultrasound technology and clarity of imaging currently available give an additional advantage to the ultrasound-based pain physician in terms of soft-tissue visualization for diagnostic and therapeutic purposes. Ultrasound-based procedures are cost-efficient and when performed appropriately are safe because the medium allows visualization of muscles, tendons, ligaments, soft tissues, and neurovascular structures in a real-time, dynamic manner. Furthermore, because of the lower cost, lack of radiation, and smaller physical footprint, ultrasound imaging can be provided within the outpatient clinical setting, thus reducing the need for specialized surgical centers and fluoroscopic imaging.
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The goal of this chapter is to provide a framework for the pain physician to gain basic knowledge and understanding of ultrasound-based procedures. We will begin with a comparison of ultrasound imaging and traditional imaging and the advantages and disadvantages of each. Thereafter, we will provide a short discussion on specific types of available ultrasound equipment and specific technical factors necessary for appropriate ultrasound use. We will also review basic techniques of scanning and needle localization using ultrasound and optimization of imaging. Finally, we will provide overviews on specific ultrasound-based procedures for neuronal structures pertinent to the pain medicine physician followed by a review of ultrasound-guided major joint injections.
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COMPARISON OF ULTRASOUND, FLUOROSCOPY, AND OTHER IMAGING MODALITIES
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Traditionally, the pain physician has used fluoroscopy as the primary imaging modality for various procedures throughout the body. Although fluoroscopy is an invaluable tool, the equipment is expensive and cumbersome, exposes the physician and patient to radiation, and requires a specialized procedure suite. Additionally, fluoroscopy is able to visualize osseous structures only. In order to see the soft-tissue targets, more cumbersome and expensive technology is required such as computed tomography (CT) or magnetic resonance imaging (MRI) guidance. With the advent of ultrasound imaging, many procedures can be done more efficiently with better visualization of regional structures without the unnecessary exposure to radiation and the technical precautions that must be instituted with their use. However, there are limitations of ultrasound use compared to traditional imaging approaches. Table 88-1 provides an outline as to advantages and disadvantages of three imaging modalities used for pain procedures: ultrasound, fluoroscopy and CT (Table 88-1).
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