Ultrasound‐Guided Thoracic Facet Injections

Objectives The purpose of this study was to describe a technique using ultrasound guidance to perform thoracic facet joint injections. Methods A single examiner used ultrasound to localize paired thoracic facet joints from T1‐2 through T10‐11 on a fresh frozen cadaveric specimen. This was done using a 2‐ to 5‐MHz curvilinear transducer over the target facet in the sagittal plain with the cadaver in the prone position. Target facets were identified using the most inferior rib as a starting point and scanning medially toward its axial attachment and further medially and slightly superior over the most caudal thoracic facet (T11‐12). Subsequent ipsilateral facet joints were identified by simply moving the transducer superiorly in the sagittal plain until the next cephalad facet was encountered. After identification, injections were performed using a long‐axis or “in‐line” approach with continual visualization of the needle into each facet joint. After needle placement, computed images were obtained from a fluoroscopy machine capable of 3‐dimensional reconstruction to assess the location of the needle tips. After this, 0.5 mL of an iodinated contrast agent was injected, and another 3‐dimensional reconstruction was performed to assess the location of the injected agent. A senior radiology resident reviewed the computed images in coronal, axial, and sagittal planes. Accuracy was determined in terms of contrast location, graded as either intra‐articular or extra‐articular. Results Sixteen (80%) of 20 injections performed showed intra‐articular contrast spread. Conclusions We describe a relatively feasible technique for performing thoracic facet joint injections using ultrasound guidance. Further verification of this technique, and modification if applicable, should be performed before directly applying this technique in a clinical practice setting.