title: Ultrasound-guided approach to the cervical articular process joints in horses: a validation of the technique in cadavers.
abstract: OBJECTIVE
  To compare accuracy of the ultrasound-guided craniodorsal (CrD) approach with the dorsal (D) approach to the cervical articular process joints, and to evaluate the effect of the transducer, needle gauge, and operator experience.
  
  
  METHODS
  Cervical articular process joints from 14 cadaveric neck specimens were injected using either a D or CrD approach, a linear (13 MHx) or microconvex transducer (10 MHz), and an 18 or 20 gauge needle, by an experienced or inexperienced operator. Injectate consisted of an iodinated contrast material solution. Time taken for injection, number of redirects, and retrieval of synovial fluid were recorded. Accuracy was assessed using a scoring system for contrast seen on computed tomography (CT).
  
  
  RESULTS
  The successful performance of intra-articular injections of contrast detected by CT using the D (61/68) and CrD (57/64) approaches was comparable. No significant effect of approach, transducer or needle gauge was observed on injection accuracy, time taken to perform injection, or number of redirects. The 18 gauge needle had a positive correlation with retrieval of synovial fluid. A positive learning curve was observed for the inexperienced operator.
  
  
  CONCLUSIONS
  Both approaches to the cervical articular process joints were highly accurate. Ultrasound-guided injection of the cervical articular process joints is an easily-learnt technique for an inexperienced veterinarian. Either approach may be employed in the field with a high level of accuracy, using widely available equipment.
authors.affiliation: Jessica Purefoy Johnson, BAgrSc, MVB, University College Dublin Veterinary Hospital, Belfield, Dublin 4, Ireland, E-mail: jessica.johnson@ucdconnect.ie.
authors.forename: Jessica
authors.initials: J
authors.lastname: Purefoy Johnson
authors.forename: John David
authors.initials: JD
authors.lastname: Stack
authors.forename: Conor
authors.initials: C
authors.lastname: Rowan
authors.forename: Ian
authors.initials: I
authors.lastname: Handel
authors.forename: John Mark
authors.initials: JM
authors.lastname: O'Leary
mesh_terms: D000818:Animals; D002102:Cadaver; D002574:Cervical Vertebrae; D003287:Contrast Media; D006736:Horses; D007270:Injections, Intra-Articular / Q000662:veterinary*; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography / Q000662:veterinary*
chemical_list: D003287:Contrast Media
keywords: Horse; cervical articular process joint; equine; ultrasound-guided