Ultrasound-guided thoracic intra-articular facet block is utilized in a variety of clinical scenarios as a diagnostic and therapeutic maneuver in painful conditions involving the thoracic facet joint. As a diagnostic tool, ultrasound-guided thoracic intra-articular facet block allows accurate placement of the needle tip within a specific facet joint that is believed to be the source of the patient’s pain. In the acute pain setting, ultrasound-guided thoracic intra-articular facet block with local anesthetics and/or steroids may be used to palliate acute thoracic spine pain emergencies while waiting for pharmacologic methods to become effective. This technique has great clinical utility when managing acute posttrauma pain. This technique is also useful in the treatment arthritis-related facet joint pain (Fig. 91.1). Clinically, pain emanating from the thoracic facet joints is perceived in the paraspinous region and radiates anteriorly in a nondermatomal pattern.

The thoracic facet joints are formed by the articulations of the superior and inferior articular facets of adjacent thoracic vertebrae (Fig. 91.2). The thoracic facet joints are lined with synovium and possess a dense joint capsule. The joint capsule is richly innervated and explains why the facet joint can serve as a nidus for thoracic pain when it becomes damaged or inflamed. The thoracic joint is susceptible to degenerative arthritis and is frequently affected by the collagen vascular diseases. The joint is frequently injured in acceleration/deceleration injuries resulting in intra-articular hemorrhage with subsequent inflammation and development of adhesions.

Each thoracic facet joint receives innervation from two spinal levels, receiving fibers from the dorsal ramus at the same level as the vertebra as well as fibers from the dorsal ramus of the vertebra above (Fig. 91.3). This fact has clinical import in that it provides an explanation for the ill-defined nature of facet-mediated pain and explains why the dorsal nerve from the vertebra above the offending level must often also be blocked to provide the patient with complete pain relief.

Ultrasound-guided thoracic intra-articular facet block can be carried out by placing the patient in the sitting position with the patient’s head resting comfortably on a padded bedside table and the arms resting comfortably on the patient’s lap (Fig. 91.4). A total of 1 mL of local anesthetic is drawn up in a 5-mL sterile syringe. If the painful condition being treated is thought to have an inflammatory component, 40 to 80 mg of depot steroid is added to the local anesthetic.

To perform ultrasound-guided thoracic intra-articular facet block, a two-step process is used. This two-step process allows the clinician to quickly identify critical anatomic structures while at the same time maintaining a transducer position that allows a safe and easy placement of needles into the selected thoracic facet joint.