Chapter 27 Thoracic Disc Access

This chapter will describe an extradural oblique technique for efficiently and safely accessing the thoracic disc. The transdural approach is not recommended or reviewed. As with lumbar discography, the final needle tip target is the nucleus pulposus, which is the geometric center of the disc.

In the thoracic spine, a single-needle technique is generally the technique of choice. However, the double-needle technique with either an 18 g with 22 g or 20 g with 25 g introducer and needle combination is acceptable. The thoracic disc is generally a smaller target than the lumbar disc, so a thinner diameter needle may allow for easier access. The needle tip can be modified as described in Chapter 2 to optimize needle navigation. It is currently acceptable to have the needle entry be contralateral to the more painful side, unless there are prohibiting issues. Multiplanar imaging will be used to best advance the needle into its final position.

The trajectory view used for this technique is very similar to that used for the lumbar technique (i.e., inserting lateral to the superior articular process between discs); however, the needle must enter medial to the rib margins. The trajectory for thoracic discography is often used for thoracic transforaminal injections as well. There is differing anatomy between low, mid, and upper thoracic levels. The more cephalic lamina are wider making it more challenging to access the disc’s geometric center above T5-6.

Thoracic provocative discography is a developing procedure that is a natural offshoot of lumbar provocative discography. As with the lumbar spine, imaging techniques are not enough to properly identify which disc or whether any thoracic disc is the source of a given patient’s pain. This technique is relatively new to the literature, having only been described for the past 20 to 25 years, but it has been found to be safe when it is properly performed. Thoracic provocation discography potentially provides a method to obtain pain-generation data with regard to the intervertebral disc. Most importantly, data collection includes pain provocation (i.e., none, discordant, or concordant) correlated with the patient’s clinical scenario. It also includes contrast volumes and disc architecture (nucleogram, post-disco CT).

Note: Please see page ii for a list of anatomical terms/abbreviations used in this book.

Trajectory View (Figure 27–1)

Figure 27–1 A, Fluoroscopic image of a trajectory view with the needle in position. B, Radiopaque structures, trajectory view. C, Radiolucent structures, trajectory view.

Trajectory View Safety Considerations

Avoid the spinal nerve.

Remain toward the base of the superior articular process (SAP) (i.e., “low in the hole”).

Avoid the dura.

While advancing the needle toward the disc, do not go too far medial or lateral. Remain immediately lateral to the junction of the endplate and the SAP. Attempt to enter the disc “low in the hole” to avoid the exiting spinal nerve.

Do not drive too far medial until entering the disc. A medial-straying needle can enter the dura.

Avoid puncturing the lungs by staying on the trajectory path and not straying ventrally or laterally.

Notes on Positioning in the Trajectory View

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