Equine cervical pain and dysfunction

Abstract

Cervical pain and dysfunction in horses has become more recognized in recent years. However, a horse may present with a long list of different clinical syndromes and the examination findings can be confusing, resulting in difficulty effectively treating the horse. This frequently leads to frustration by the owner, as well as the veterinarian charged with helping the horse. This body of work aims to enlighten the reader of the dearth of understanding of cervical pain and dysfunction, to highlight how dangerous behavior may be related to cervical pain, and describe the course and development of future research. There is a paucity of peer-reviewed equine literature available describing cervical pain and dysfunction in the horse. The first chapter is designed to provide a synopsis of the current state of understanding of the disease processes, diagnostic capabilities, and possible treatment strategies available to manage cervical pain and dysfunction in horses. The second chapter describes a series of horses displaying unwanted behavior that became dangerous to the rider and often times to the horse itself. The included horses all had moderate to severe ganglionitis at multiple vertebral levels. Ganglionitis has been associated with neuropathic pain in other species, and is believed to be causing a state of neuropathic pain in this series of horses. This study highlights the need for deeper understanding of pain behavior in horses. Chapter 3 describes a prospective evaluation of cervical pain and dysfunction in 12 horses. Recombinant equine interleukin-1β (reIL-1β) has been used as an acute synovitis model within the appendicular skeleton and was utilized in this study to create transient synovitis at the cervical articulation of C5-C6. This study evaluated the clinical, biomechanical and ultrasonographic features in horses with a known source of neck pain. Acute synovitis of the articular process joint (APJ) induced clinical signs of myofascial pain and neck stiffness with variable degrees of forelimb lameness. Ultrasonographic evidence of the presence and severity of APJ effusion could be readily identified and tracked over time. Utilizing this model in the future could further add to our understanding of the clinical presentations in horses experiencing cervical pain and dysfunction. Through this collection of work, we have developed collaborations to investigate many unanswered questions that have been raised. We will look to define pathways related to neuropathic pain mechanisms in order to ultimately improve the quality of life, not only for our equine patients, but potentially of other veterinary species and even the human population experiencing chronic pain.