Spinal Epiduroscopic Radiofrequency Therapy

20 Spinal Epiduroscopic Radiofrequency Therapy

Paulo Pereira and Pedro Monteiro

20.1 Introduction

Although the mechanisms of recurrent/persistent postoperative radicular pain and its relation with epidural fibrosis remain incompletely understood,1 a series of patients have been reported to benefit with targeted approaches, namely, transforaminal epidural steroids, epiduroscopy, and adhesiolysis.² While more common after spinal surgery, epidural adhesions can also occur in patients not operated, in response to the release of proteoglycans from the nucleus pulposus into the epidural space through tears in the annulus fibrosus, or due to the presence of infection, hematoma, or contrast dye in the epidural compartment.²

Several techniques have been used for epiduroscopic adhesiolysis, namely, mechanical (performed with the tip of the endoscope, a Fogarty catheter or similar), electrothermal (using a laser or radiofrequency [RF] energy), and chemical (hyaluronidase).³ One of the advantages of using RF for epidural adhesiolysis is to vaporize and coagulate the epidural fibrous bands keeping the tissue temperature below 50°C.⁴

20.2 Step 1: Sacral Hiatus Epiduroscopic Approach

• Endoscopic approach to the spinal epidural space through the sacral hiatus ( Fig. 20.1) has been described in Chapter 9. Through the spinal needle, the RF probe can be passed into the epidural space and maneuvered to the area of interest ( Fig. 20.2).

• Conscious sedation and systemic analgesia are strongly recommended when adhesiolysis is planned during epiduroscopy to render the procedure more comfortable for the patient.

• Epidurography is useful to identify areas not filled with the contrast dye, usually corresponding to extensive epidural fibrosis, blocking the epidural or periradicular space, where the epiduroscope is primarily directed.

Fig. 20.1 Percutaneous insertion of the spinal needle through the sacral hiatus into the epidural space.

20.3 Step 2: Irrigation of the Epidural Space with Saline

• Small boluses of isotonic saline are repeatedly flushed in the epidural space, accomplishing several purposes:

Opening the epidural space and cleaning the visual field.

Tearing mild fibrosis bands.

Controlling minor bleedings.

Cooling down the neural structures when performing epidural RF.

Washing out inflammatory mediators (such as phospholipase A2, tumor necrosis factor-α, interleukin [IL]-1β, IL-6, or IL-8) from the epidural space.

• Care must be taken concerning the volume of fluid injected in the epidural space and the speed and pressure of injection to avoid increase of the epidural and subarachnoid pressure and the consequences that may arise related thereto. We monitor but do not limit the volume of saline solution used for irrigation. Instead, we prefer not using a valve in the portals of the endoscope and injecting the saline in small boluses, which allows the fluid to exit the spinal canal through the portals and the intervertebral foramina. Moreover, in the rare case the patient reports any relevant symptom, we hold the procedure for a few minutes.2

20.4 Step 3: Mechanical Adhesiolysis

• Mechanical adhesiolysis shall precede the RF therapy and might be all that is required in cases with less thick fibrosis.2,5

• The tip of a Fogarty catheter may be used to dissect mild adhesions ( Fig. 20.3). The balloon is usually inflated and moved back and forth to stretch and tear denser areas of fibrosis and provides more available space in the local epidural area ( Fig. 20.4). It can also be useful for mechanical hemostasis.

• A 1-mm flexible endoscopic grasping forceps can be used to remove epidural scar tissue if no blood vessels are identified in the vicinity ( Fig. 20.5).