Lumbar Transforaminal Epidural Steroid Injection—Supraneural, Two-Needle Technique: Fluoroscopic Guidance

Abstract

The 2-needle technique is known to many in the interventional spine field as a method commonly used to access the intradiscal space. In some circles, this technique is also used to perform both supranerual and infraneural transforaminal epidural injections. One cited reason mirrors that for intradiscal procedures: the 25g needle that passes through the introducer and enters the neuroforamen never touches the skin, theoretically reducing the risk of introducing pathogens into epidural space (though there are no published studies addressing this hypothesis).

The main advantage of the 2-needle technique is that it allows the interventionalist to elegantly bypass hardware, fusion masses, large osteophytes, and other barriers when an unobstructed trajectory view to the target zone cannot be obtained. This is achieved by placing the introducer lateral and ventral to an obstruction, then using the bevel of the introducer as a new “trajectory view”. An appropriately bent 25g needle threaded through the tip of the introducer can drive medially with very little ventral movement, allowing for maneuverability that is not possible with a single needle approach.

Keywords

Double needle, Epidural, fluoroscopy, Introducer

Note: Please see pages ii , iii for a list of anatomic terms/abbreviations used throughout this book.

The two-needle (aka double needle) technique is a common method used to access the intradiscal space but may also be utilized to perform supraneural and infraneural transforaminal epidural injections. One advantage of this technique is increased maneuverability to bypass barriers (hardware, osteophytes, fusion masses, etc.) to the target zone, since an appropriately bent injection needle through an introducer tip can be driven medially with little ventral movement. The introducer tip creates a new point of trajectory from which more extreme directions can be achieved at target depth. We will describe trajectory and multiplanar views for introducer needle placement and multiplanar views for a supraneural injection needle placement. Although not demonstrated in this atlas, the two-needle technique can also be used for infraneural injection needle tip placement.

Phase 1: Introducer Needle Placement

Trajectory View

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Confirm the level (see Chapter 1 ).
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Tilt the fluoroscope cephalad or caudad to line up the corresponding superior end plate (SEP) as in Chapter 13A (supraneural approach).
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  Oblique the fluoroscope ipsilaterally.
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  The target introducer needle starting point is lateral to the pedicles and between the transverse processes (if performing an L1-L4 transforaminal epidural steroid injection [TF-ESI]) or between the L5 transverse process and the sacral ala (if performing an L5 TF-ESI) The target should have a clear, unobstructed path that does not overlie the periosteum (see Fig. 13B-01A and 01B ).
  
  Fig. 13B.1
  
  A, Fluoroscopic image of trajectory view with introducer needle in position. B, Radiopaque structures, trajectory view. C, Radiolucent structures, trajectory view.
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  Place the introducer needle parallel to the fluoroscopic beam , gain purchase in paraspinal musculature, and then move on to the AP view.

Trajectory View Safety Consideration

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Avoid contacting the spinal nerve (SN) with the introducer needle by staying superior to it.
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Use AP and lateral views for further safety considerations.