Technique for ultrasound-guided intraarticular cervical articular process injection in the dog

Ultrasound-guided intraarticular injection of cervical articular process joints is a well-established procedure in both humans and horses for neck pain resulting from osteoarthritis, but the technique has not been described in dogs. Aims of this study were to describe the ultrasonographic anatomy and landmarks for cervical articular process joint injections in the dog, develop a technique for articular process joint injections using these landmarks, and determine the accuracy of injections and factors that may influence it. Eleven canine cadavers were used and bilateral joint spaces from C2-3 to C7-T1 were injected under ultrasound guidance with a blue radiopaque solution. A computed tomographic scan was acquired following each injection, and an injection score was assigned and compared with other patient-specific factors. Of the 132 injections performed, 110 (83.3%) were intraarticular, 20 (15.1%) were periarticular within 5 mm, and 2 (1.5%) were periarticular beyond 5 mm from the joint. There was no significant difference in mean scores between dogs. Only C2-3 had a significantly lower mean score than any other joint. There was no significant correlation between injection score and any other factors measured. The transverse processes of the cervical vertebrae served as excellent ultrasonographic landmarks for identifying the cervical articular process joints in dogs regardless of the size of the dog or location along the vertebrae. Accuracy of ultrasound-guided intraarticular process joint injection was 83% in dogs and similar to published techniques in horses. Further studies are needed to examine the safety and efficacy of this procedure in live animals.