The Modern Equine Vet
April 2024
Vol 14 Issue 4 2024
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Technician Update

Cervical Injuries Due to Rotational Falls

By Jessica Cook

These 2 cases come from the realm of timber racing and involve rotational falls incurred at speed. With the horse’s best interests at heart, and an increasing awareness of safety protocols, I think horses who incur rotational falls should be required to have their cervical spine cleared by diagnostic imaging prior to returning to work.

This can be applied in all disciplines for the safety of both horse and rider. One case represents cervical injuries diagnosed by radiographs taken at the horse’s primary stable. The final case is an example of potentially undiagnosed injury from rotational fall approximately 2 years prior to development of clinical signs.

Case 1
Inciting Rotational Fall: A 6-year-old timber racehorse sustained a rotational fall, regained his footing and jumped off course before being caught. The horse was evaluated briefly at the racing venue and deemed safe to ship 3 hours home.

Clinical Evaluation: At the trainer’s request the horse was evaluated the following Monday. Upon examination the horse had significant stiffness and was unable to graze comfortably. There was visible deformation in the cranial cervical region with sensitivity to palpation. He was observed in hand at a walk in a straight line and figure 8. A bilateral hind limb toe drag was seen, but no other neurologic signs were evident. Placement tests of all 4 limbs were within normal limits.

Diagnostic Approach and Diagnosis: Radiographs were performed with standing sedation in a rope halter to avoid metallic interference with images. Fracture and ventral displacement of the atlantoaxial articulation with associated distortion of the vertebral canal was elucidated with the first radiograph. A cervical spine survey was completed with no other significant findings on lateral or ventrodorsal views.

Rehabilitation: The horse was placed on strict stall rest for 90 days with feed, forage and water at chest height. He was maintained on phenylbutazone for 5 days administered at a dosage of 1 g twice daily for 5 days, 1/2 g twice daily for 3 days and then discontinued. The gelding also received gastroprotectant medication while on nonsteroidal medication and was closely monitored for any discomfort or deterioration in proprioception.

Following his initial confinement, case 1 was transitioned to a small paddock and then ultimately large field turn out for 5 months. He was not reported to have any negative change in condition or movement during the progression. Serial clinical and radiographic examination was performed at the 5-month mark. The ventral deviation was still visible but unchanged. Baseline movement in a straight line and figure 8 was repeated with no proprioceptive concerns revealed.

Radiographs were repeated and showed osteoarthritic changes because of the fracture and displacement. There was the development of enthesophyte on the caudal occiput in the enthesis of the ligamentum nuchae. The deviation in alignment was compared with the original radiographs and was unchanged.

Outcome: The patient in this case resumed work progressively increasing until returning to training as a timber horse. Following his injury he raced 8 times, including a win, before ultimately retiring to become a fox hunter. He was hunted successfully for several seasons.

Case 2
Inciting Rotational Fall: An 8- year-old Thoroughbred racing in a timber race had a rotational fall and then regained his feet before being caught in the van area. Due to his fall during an unsanctioned race, it was not required for him to be evaluated prior to shipping home. There were no reports of any movement concerns for nearly 2 years. Approximately 2 years after the fall the horse was found to be acutely ataxic in all 4 limbs, and the trainer requested an emergency visit after administering IV flunixin meglumine himself.

The horse was seen by an associate veterinarian who deemed him capable of shipping and referred him to the hospital after administration of IV dexamethasone and bolus fluids.

Diagnostic Approach and Diagnosis: Upon arrival at the referral hospital the horse presented with ataxia of all 4 limbs and muscle fasciculation around the head and neck. Nuclear scintigraphy of the region was deemed within normal limits and the equine protozoal myelitis (EPM) testing was negative. Neutral lateral radiographs were performed during a myelogram as well as in flexion.

In the neutral position there was compression of the spinal cord in the caudal portion of the vertebral canal of C6 with both dorsal and ventral impingement of the dye column, In the flexed position the C6 impingement persists as well as obliteration of the ventral dye column at C2/3, C4/5, and C5/6. However, the dorsal dye column was not diminished by more than 50%.

Rehabilitation: Due to the results of the myelogram and clinical picture the gelding was euthanized and submitted for postmortem examination.

Outcome: The postmortem images demonstrate the findings of a significant lytic lesion found on the vertebral head of C6 and associated cystic mass within the spinal canal at this location. It can be presumed that both are a result from the trauma he incurred, although congenital defect cannot be ruled out. MeV

Teaching Points

1. Cervical injuries do not have to be accompanied by neurologic deficits, even in the most extreme cases.

2. Horses should be thoroughly evaluated by a physical examination and imaging in the event of a rotational fall whether there are any neurologic deficits.

3. Immediate diagnosis of cervical injuries can determine rehabilitation, prognosis and management for the safety of both horse and rider in future athletic endeavors or full return to previous levels of activity.

About the Author

Jessica began in Equine Sports Medicine of Maryland, in 2003 with Cooper Williams, VMD, when he was a single practitioner. After horse showing for several years in the hunter/jumpers, she was hired by the practice and trained by Dr. Williams. She has a special fondness for the racehorses within the practice but enjoys getting to know the variety of patients they see. Being an assistant to Dr. Williams, Jess has relished the opportunity to learn and aid in diagnostic imaging. In 2018 and 2023, she submitted case studies to the American Association of Equine Veterinary Technicians and was selected to have the paper printed in the proceedings, as well as present the case at the national convention. She has had articles published with modernequinevet.com online magazine in reference to the practice’s “whole horse” philosophy and has continued submissions for future use. When not involved with horses, Jess enjoys gardening and hiking with her hound mix, Pilot, who often accompanies her and Dr. Williams on the road.

Case 1: Visible deformation in the cranial cervical region, which was sensitive to palpation.

Lateral radiograph of atlantoaxial joint – normal joint.

Lateral radiograph of atlantoaxial joint – fracture and ventral displacement.

Lateral radiograph of atlantoaxial joint at 5 months.

Case 2: Malalignment in flexion C6 and C7 and visible deformation of C6 vertebral head: Arrow directed at the C6 vetebral head abnormality.

Postmortem images demonstrate a significant lytic lesion found on the vertebral head of C6.

Postmortem image demonstrates associated cystic mass within the spinal canal at this location.

Images: Courtesy of Equine Sports Medicine of Maryland and used with the permission of Cooper Williams, VMD