Radiofrequency Use in Ankle and Foot Arthroscopy



Radiofrequency Use in Ankle and Foot Arthroscopy


JAMES P. TASTO

BRENNEN L. LUCAS



This chapter outlines uses of radiofrequency (RF) in foot and ankle surgery, specifically arthroscopy, but will cover some minimally invasive techniques as well. RF has become increasingly popular, and as the science behind it continues to expand, it has become a growing and exciting area in arthroscopy.

In the previous edition of this book, laser technology was discussed in detail in a chapter titled “Future Developments.” Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. The laser, like RF in some ways, can be used to cut, coagulate, and vaporize tissue. The laser utilizes energy in a single beam of light. Both can significantly increase the temperature of the target tissue, but the Coblation technology in RF does not transmit heat directly to the target tissue. As most would agree, the use of laser technology in foot and ankle surgery has fallen out of favor for a multitude of reasons, and therefore, this chapter focuses on RF.1




PRINCIPLES

Many foot and ankle conditions are successfully treated conservatively. There are a variety of arthroscopic and minimally invasive procedures available when conservative treatment fails. RF is one of the newer technologies available to the arthroscopist.

RF utilizes an alternating current. The patient’s tissue provides the impedance that produces the resistance in the tissues allowing the body to become part of an electrical circuit. RF devices generally have either a monopolar or a bipolar configuration. With monopolar RF, there is a small active electrode that is used by the surgeon and a larger grounding electrode distant to the surgical field. A bipolar probe contains both the active and the return electrodes within the surgical probe making a distant grounding pad unnecessary.6 Coblation technology works by forming a plasma layer using a saline solution. This process produces chemical radicals like OH that can cause volumetric removal of biologic material rather than simply burning it.7 Bipolar RF has become a popular tool in orthopedic surgery with a wide array of applications.


TECHNIQUE

Use of RF devices in arthroscopy is similar to mechanical debridement devices. The device is introduced through a secondary portal and different settings, and modes can be utilized depending on the desired effect. As stated above, various devices may be either monopolar or bipolar and have different settings including Coblation in some cases.

When performing synovectomy, applying pressure through the probe to the tissue is accepted, but when performing chondroplasty, we prefer to employ a “no touch” technique with Coblation while allowing the chondroplasty to be performed at the level of the plasma layer. The Coblation technique creates a charged plasma gas that has sufficient energy to break molecular bonds within tissue at temperatures between 40°C and 70°C. The RF current does not pass directly through the tissue.

When using the different devices, it is absolutely necessary to understand the critical settings for the particular device in use. For example, the temperature created in the tissue being treated is not necessarily higher with a higher setting on the control box (Fig. 18-1). These settings will differ within different devices from the same company and also between companies.







FIGURE 18-1. This graph demonstrates the relationship of the power setting for a certain ArthroCare wand device used in arthroscopic procedures. The temperature and power actually decrease at a higher power setting once the device enters the plasma state. (Courtesy of ArthroCare.)


Sep 25, 2018 | Posted by in RHEUMATOLOGY | Comments Off on Radiofrequency Use in Ankle and Foot Arthroscopy
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