title: Ultrasound-guided thoracic facet injections: description of a technique.
abstract: OBJECTIVE
  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.
authors.affiliation: Departments of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Stulc
authors.forename: Mark F B
authors.initials: MF
authors.lastname: Hurdle
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Pingree
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Brault
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Porter
mesh_terms: D002102:Cadaver; D003287:Contrast Media; D005240:Feasibility Studies; D006801:Humans; D007270:Injections, Intra-Articular / Q000379:methods*; D009407:Nerve Block / Q000379:methods*; D010743:Phospholipids; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging*; D018084:Ultrasonography, Interventional / Q000379:methods*; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride