Ultrasound-guided thoracic facet injections: description of a technique

• Published in: Journal of ultrasound in medicine 2011-03, Vol.30 (3), p.357-362
• Main Authors: Stulc, Steven M, Hurdle, Mark F B, Pingree, Matthew J, Brault, Jeffrey S, Porter, Christopher A
• Format: Article
• Language: English
• Subjects: Cadaver; Contrast Media; Feasibility Studies; Humans; Injections, Intra-Articular - methods; Nerve Block - methods; Phospholipids; Reproducibility of Results; Sensitivity and Specificity; Sulfur Hexafluoride; Thoracic Vertebrae - diagnostic imaging; Ultrasonography, Interventional - methods; Zygapophyseal Joint - diagnostic imaging
• ISSN: 0278-4297; 1550-9613
• DOI: 10.7863/jum.2011.30.3.357

The purpose of this study was to describe a technique using ultrasound guidance to perform thoracic facet joint injections. 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. Sixteen (80%) of 20 injections performed showed intra-articular contrast spread. 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.