Thoracic interlaminar epidural steroid injections are indicated more commonly for radiculopathy caused by a disc protrusion or stenosis of the central canal, intervertebral foramen, or lateral recess. These injections can also be used less commonly for the treatment of radiculopathy as a result of degenerative disc disease, compression fractures, acute herpes zoster, or postherpetic neuralgia.

Thoracic interlaminar epidural steroid injections are typically performed using a paramedian approach. As a result of the significant caudad and oblique angulation of the overlapping thoracic spinous processes, it is difficult to perform a median (midline) technique, particularly at the mid to upper thoracic levels. The paramedian approach in the thoracic spine allows the physician to “work around” and thus avoid the spinous processes when placing the needle tip in the interlaminar space.

A spinal needle can be used as a marker with the tip in contact with the superior lamina of the targeted interlaminar space in the anteroposterior (AP) view as long as the laminar bone is visible. The thoracic interlaminar epidural injection is performed with the “marker” so that there is no mistaking the level of injection when maneuvering the fluoroscope from the AP view to the caudally tilted trajectory view. The epidural needle is placed with the use of a paramedian trajectory view using fluoroscopic imaging and confirming the position and depth of the needle tip via the AP, lateral, and contralateral oblique (CLO) views.

For thoracic interlaminar epidural injections, advancing the epidural needle in the lateral or CLO view provides a safe approach into the epidural space, which is not offered by traditional AP only views. The CLO view enables visualization of the angle of the interlaminar space that is otherwise not evident with the AP or lateral view (see Chapter 3 ). This technique identifies the interlaminar space by optimizing the visualization of the laminae that border the space. The epidural needle is advanced through the space and beyond the ventral interlaminar line (VILL) to engage the ligamentum flavum. The epidural space is then identified after the use of a loss-of-resistance (a.k.a change of resistance) technique with air, saline, air and saline, or the hanging drop technique. The use of saline is preferred to an air only technique to avoid a seizure or cord compression from an inadvertent subarachnoid injection of air.