Equis ISSN 2398-2977

Spine: fracture

Contributor(s): Caroline Hahn, Chris Whitton

Introduction

Pathogenesis

Etiology

Pathophysiology

Atlas and axis
  • Position of halter at poll and lack of fibrous intervertebral disk predisposes.
  • Hyperflexion, extension, lateral bending   →   disruption of the dens physis   →   separation of the odotonoid process; pull of nuchal ligament   →   ventral luxation of the axis.
  • Atlantal arches and wings commonly involved.

Atlantoaxial subluxation

  • Primary idiopathic subluxation.
  • Trauma   →   extension   →   compression of the spinal cord.

Atlantoaxial luxation

  • Rare.
  • Trauma   →   disruption of the longitudinal ligament and the paired ligaments of the apex of the dens   →   complete luxation of the articulation with ventral displacement of the odotonoid proces of the axis.

Middle and caudal cervical vertebrae

  • Hyperflexion, extension, lateral bending   →   fractures of C3   →   C6; usually C3 and 4.
  • Tearing of synovial joint capsule   →   permits lateral bending   →   subluxation.
  • Horses <2 years may have separation of the cranial and caudal physes.
  • Hyperextension   →   separation of facets, tension on vertebral bodies   →   separation of caudal epiphysis; OR, shearing of dorsal shelf of vertebra; pull of nuchal ligament   →   maintains hyperextended configuration.
  • Neurologic deficit depends on degree of spinal cord compression.
  • Healing of hyperextended fractures   →   instability of adjacent vertebrae   →   later return of ataxia.
  • Healing may result in resolution of ataxia, but then callus formation increases pressure on spinal cord   →   signs return.

Thoracolumbar vertebrae

  • Fall   →   catastrophic comminuted fracture, usually T12 or T5 involved.
  • Rearing and falling backwards   →   fractured dorsal spinous processes.

Sacrum and caudal vertebare

  • Falling backward, backing up, sitting down suddenly.

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Piat Pet al(2012)Fractures of the withers in horses.Equine Vet Educ24(11), 582-588 VetMedResource.
  • Lloyd D (2009)Cervical spine injuries.Equine Vet Educ21(10), 533-535 Wiley Online Library.
  • Mayhew I G (2009)Cervical vertebral fractures.Equine Vet Educ21(10), 536-539 Wiley Online Library.
  • Muno J, Samii V, Gellatin L, Robertson J & Chase J (2009)Cervical vertebral fracture in a Thoroughbred filly with minimal neurological dysfunction.Equine Vet Educ21, (10), 527-531 VetMedResource.
  • Withers J M, Voute L C & Lischer C J (2009)Multi-modality diagnostic imaging of a cervical articular process fracture in a Thoroughbred horse, including a novel C-Arm imaging technique.Equine Vet Educ21(10), 540-545 VetMedResource.
  • Hahn C (2006)The wobbly horse: differential diagnoses.In Pract28(1), 8-13 VetMedResource.

Other sources of information

  • Nixon A J (1996)Equine Fracture Repair. W B Saunders, Philadelphia. ISBN-10: 0721667546.


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