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

Abstract

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 ultrasoundguided 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.

Safety and accuracy of blind vs. ultrasound‐guided dorsal retrobulbar nerve blocks in horses—A cadaveric study

“…One of the main advantages of using US guidance for injections is the avoidance of vital structures. One could argue the technique described by Morath et al 14 does not completely meet all the criteria to be classified as a safe US‐guided injection technique, 24 as the relevant structures cannot all be visualized simultaneously in real time during the procedure. This applies to most of the cases in both our study and the study by Morath et al 14 In another study, 15 an in plane ultrasonographic approach was proposed for a peribulbar nerve block with a phased array ultrasound transducer placed in the supraorbital fossa.…”

Objective methods of nerve localisation to facilitate performing locoregional anaesthetic techniques for horses undergoing surgical procedures

“…A number of advanced techniques for the equine head have recently been developed, such as ultrasound‐guided, advanced imaging‐guided and nerve stimulator‐guided techniques. This topic has been recently reviewed in two excellent narrative reviews, where the authors discussed the use of perineural nerve blocks for the equine head, exploring the advantages and disadvantages of blind approaches as well as approaches guided by ultrasound, nerve stimulation or advanced imaging techniques (Hermans et al., 2019; Johnson et al., 2021). Furthermore, the authors highlighted the wide range of clinical applications for ultrasound‐guided procedures of the equine head and compared human and equine literature, examining the potential of perineural techniques for both diagnostic and therapeutic purposes.…”

“…Furthermore, the authors highlighted the wide range of clinical applications for ultrasound‐guided procedures of the equine head and compared human and equine literature, examining the potential of perineural techniques for both diagnostic and therapeutic purposes. As techniques in the field are constantly evolving, ultrasound guidance is becoming an increasingly popular and utilised modality worldwide for locoregional anaesthesia of the head in equine patients (Hermans et al., 2019; Johnson et al., 2021). Consequently, the authors of the current review have not included locoregional techniques involving the head for dental or ocular procedures.…”

“…The purpose of this review is to discuss the most pertinent research in the veterinary literature where objective methods of nerve location have been used to perform peripheral nerve blocks in horses (Table 1). This review will exclude objective methods used to perform peripheral nerve blocks of the head, as these have been recently reviewed elsewhere (Hermans et al., 2019; Johnson et al., 2021).…”