Cervical facet radiofrequency

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The use of electricity to treat painful conditions is not novel in medicine. Initially, direct current was used to create lesions of the nerves, but the unpredictable results lead to the adoption of alternating current. Current radiofrequency generators allow us to locate the target nerve, decrease the chance of unwanted nerve damage, and control temperature in the surrounding tissues. The cervical facets commonly cause cervicogenic headaches or cervicobrachialgia. The medial branches of the cervical dorsal rami innervate the facets and are easily accessible for radiofrequency, with the addition of fluoroscopy. Two modalities of radiofrequency are currently available. The traditional neurolytic technique creates high temperatures around the tip of the needle burning the target tissues, while pulse radiofrequency creates an electrical field around the nerve, that modulates nerve conduction while preventing nerve damage. We describe the most common technical approaches to perform the above mentioned procedures, with a rationale to decide why and when to perform pulse radiofrequency or neurolysis.

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Anatomy

The cervical facet (zygopophysial) joints are formed by the superior and inferior articular process of two adjacent vertebrae. The cervical facets, from C3 to 4 to C7-T1, are lined with synovium and possess joint capsule.

The cervical zygopophysial joints (from C3-4 to C7-T1) are innervated by the medial branches of the cervical dorsal rami (Figure 1).6 The medial branches curve medially, “hugging the waists” of their segmental articular pillars, and divide as the nerve approaches the posterior

Basic principles of radiofrequency

Application of electrical current to lesion specific nerve targets has been clinically used since the 1940s when direct current (DC) was applied. The unpredictability of the lesions led to the adoption of alternating current (AC) and high frequency waves (about 300 kHz).

Currently, radiofrequency generators can measure tissue temperature around the electrode tip, perform electrical stimulation to facilitate nerve location, (decreasing the chance for nerve damage), and measure tissue impedance.

Required equipment

The procedure should be performed under fluoroscopic guidance (C-arm). Equipment and medications for cardiopulmonary resuscitation should be readily available in case of anaphylactic reactions, or cardiovascular collapse, due to intrathecal or intravascular injection of local anesthetic. Required monitoring equipment includes: EKG monitor, pulse oximetry, and blood pressure.

A radiofrequency generator will display voltage generated, impedance, voltage, and temperature. To avoid undesired

Lateral approach

When performing radiofrequency for the upper cervical facet joints (C2-3, C3-4, C4-5, C5-6), I prefer to have the patient in the supine position, with the neck in neutral position, as it gives one better access to the neck and allows an increased patient tolerance. The C-arm is placed in a lateral view (Figure 3A). Then the patient’s head is slowly rotated, so as the bilateral articular processes are superimposed. Then the C-arm is slightly rotated to oblique view, allowing the physician to see

Complications

Like any other minimally invasive procedure, theoretical risks associated with the needle placement include hematoma formation, infection, and allergic reaction to the local anesthetic. Potential complications inherent to radiofrequency are the development of burns if the dispersing ground is not properly applied.

The posterior approach offers the advantage that the vertebral artery, the spinal nerves, and the radicular arteries lay anterior to the final anterior location of the needle. Damage

Conclusion

When performed properly, radiofrequency lesioning (RFL) applied to the nerve supply of the cervical facet joints can provide long-term relief from pain emanating from the joints. Appropriate diagnostic injections of the medial branches that innervate the symptomatic facet joint or joints should be performed before RFL to improve the success rate.

Complications can be avoided by proper needle placement, making sure that equipment is in good operating condition and checking that the dispersing

Acknowledgments

I thank Kristine M. Dennis for manuscript preparation.

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