Equis ISSN 2398-2977

Mandible/maxilla: fracture

Contributor(s): Stephen Adams, Patrick Colahan, Bud G E Fackelman, Chris Whitton, Graham Munroe

Introduction

  • Cause: external direct trauma, either self-inflicted or from kicks and falls.
  • Signs: vary from local swelling and wounds → dysphagia; malocclusion, halitosis, ptyalism.
  • Diagnosis: manual examination, radiography Head: radiography.
  • Treatment: depends on configuration of fracture but some are effectively treated conservatively. Surgery - tension band wiring Bone: internal fixation - wires Mandible: fracture 07 - repair (wire), cross-pinning Bone: internal fixation - pins and nails Mandible: fracture 03 - repair - VD radiograph, plating Bone: internal fixation - plates.
  • Prognosis: variable - good for rostral injuries, guarded for fractures of angle of mandible and its rami; poor for temporomandibular involvement.

Pathogenesis

Etiology

Incisive region, including incisor bone, premaxilla and rostral mandible

  • Direct trauma:
    •  Occasionally kicks, falls or collisions but commonly there is a history of the animal playing with an object and then being startled and not letting go of that object.
    • Particularly common in young horses playing with fences, feeders or buckets, or in cribbing adults.
  • Avulsion fractures of the incisor region, particularly the mandible, are the most common.
  • Slightly more caudally, at the interdental space, is also a predisposed anatomical site.
  • Often involve the incisor teeth, particularly on the labial aspect of the teeth.
  • Teeth themselves may be fractured, particularly in the incisor region, potentially exposing sensitive pulp tissue. In addition, the roots of teeth may be damaged by fracture lines leading to instability of the tooth and/or infection Dental examination.
  • Many displaced fractures of these regions are open, heavily contaminated and may have hematoma within the fracture line.

Maxilla, caudal horizontal and vertical mandibular rami

  • Kicks are particularly common in this region but also collisions, falls and self-induced trauma can occur. Occasionally jaw fractures may occur as a secondary consequence of dental disease Teeth: dental disease - overview or iatrogenically following dental extraction Teeth: extraction.
  • Maxilla may have subtle depression fractures → open fracture with substantial bone loss → exposure of the paranasal sinuses, dental roots or periorbital tissues.
  • Fractures of caudal horizontal and vertical rami less common because of wider, thicker bone, protection by masseter muscle and molar reinforcement.

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.
  • Jansson N (2016) Conservative management of unilateral fractures of the mandibular rami in horses. Vet Surg 45 (8), 1063-1065 PubMed.
  • Caldwell F J & Davis H A (2012) Surgical reconstruction of a severely comminuted mandibular fracture in a horse. Equine Vet Educ 24 (5), 217-221 VetMedResource.
  • Kuemmerle J M (2012) Mandibular fractures in horses. Equine Vet Educ 24 (5), 222-224 Wiley Online Library.
  • Ramzan P H L (2008) Management of rostral mandibular fractures in the young horse. Equine Vet Educ 20 (2), 107-112 VetMedResource.
  • Belsito K A & Fischer A T (2001) External skeletal fixation in the management of equine mandibular fractures - 16 cases (1988-1998). Equine Vet J 33 (2), 176-183 PubMed.
  • Henninger R W, Beard W L, Schneider R K, Bramlage L R & Burkhardt H A (1999) Fractures of the rostral portion of the mandible and maxilla in horses: 89 cases (1979-1997). JAVMA 214 (11), 1648-52 PubMed.
  • Ragle C A (1993) Head trauma. Vet Clin North Am Equine Pract (1), 171-183 PubMed.

Other sources of information

  • Furst A E & Auer J A (2018) Craniomaxillofacial Disorders in Equine Surgery. 5th edn. Eds: Auer J A & Stick J A. Elsevier Saunders, USA.


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