Ultrasound-guided injections of the equine head and neck: review and expert opinion

Ultrasound-guided injections can be used for a wide variety of conditions in the horse, including both diagnostic and therapeutic applications. Benefits of ultrasound guidance include more accurate deposition of injectate compared with blind approaches. Improved identification of vital structures, including nerves and blood vessels, allows their avoidance and thus reduces procedure-associated complications. Validation of such ultrasound-guided techniques has shown that they can be easily learnt by inexperienced veterinarians, assuming a proper knowledge of the sonographic anatomy. In many cases they can be employed in the field with a high level of accuracy, using widely available equipment, and with complete adherence to the sterility principles. Many ultrasound-guided injection techniques of the axial skeleton in the horse have been described in past years, enabling the equine veterinarian to perform more accurate treatments of specific anatomical areas. The goal of this review is to discuss diagnostic and therapeutic ultrasound-guided injection techniques of the skull and cervical spine in the horse, including those for the retrobulbar space, maxillary and inferior alveolar nerves, atlanto-occipital and atlanto-axial junctions, and cervical articular process joints, as well as the 1st cervical nerve, the C2 and C3 nerve plexus, and the 6th, 7th, and 8th cervical nerve roots.