Equis ISSN 2398-2977

Cervix: trauma

Contributor(s): Madeleine L H Campbell, Graham Munroe, Sarah Stoneham, Vetstream Ltd

Introduction

  • The cervix is the last physical barrier to the uterus and has a vital role in uterine defense.
  • Cause: trauma to the cervix occurs most commonly at foaling, especially if protracted or assisted.
  • Signs: cervical damage may be detected post-partum on manual or vaginoscopic examination or may go undetected and result in decreased fertility.
  • Diagnosis: manual examination is recommended at ~3 weeks post-partum in any mare with dystocia; tears may be obvious at the time of foaling if large, but smaller defects may be difficult to appreciate until involution has occurred. Direct vaginoscopic evaluation.
  • Treatment: small lacerations and mucosal defects may be managed conservatively with antibiotics and anti-inflammatory creams to prevent the formation of adhesions, and sometimes the use of exogenous progesterone to maximize cervical closure. Larger defects require surgery   Cervix: trauma - repair  .
  • Prognosis: good for rebreeding in the case of simple tears and lacerations. Prognosis for future breeding is guarded in the case of severe and multiple tears, as mare will often re-tear, or repair may not be possible or artificial seal remains incompetent.

Pathogenesis

Etiology

  • Difficult, protracted or assisted foaling, especially where fetotomy has been performed.
  • Occasionally occurs where there is no history of a difficult foaling or only fetal oversize.
  • Occasionally seen post-breeding due to damage from stallion's penis when mare's cervix incompletely relaxed at mating or where stallion is excessively vigorous and/or oversized.
  • Could occur as a result of poor technique during artificial insemination   Reproduction: artificial insemination  .
  • Irritant chemicals used for intrauterine treatment.
  • Chronic endometritis or long-standing pyometra   Uterus: pyometra  .

Specific

  • Previous cervical damage.

Pathophysiology

  • The cervix is made up of longitudinal muscle along its body and circular muscle at the internal and external os.
  • The shape and function of the cervix is determined by hormonal control.
  • At oestrus, the cervix is open and relaxed, allowing the expulsion of any contaminants accumulating after foaling, breeding or treatment.
  • During diestrus, the cervix is tight and closed, preventing the loss of the early embryo and the ascent of external infections.
  • Any interference with this dynamic function of the cervix will lead to conceptual failure by obstructing the lumen or preventing adequate closure (thus predisposing the mare to endometritis   Uterus: endometritis - bacterial  ).
  • Trauma to the cervix may lead to mucosal defects, adhesions, lacerations and incompetence.
  • Areas of roughened mucosa or exposed submucosa may epithelialize spontaneously or with treatment.
  • If mucosal defects are not treated or are slow to heal, then submucosal tissue will be in opposition allowing fibrous adhesions to form.
  • The scar tissue may organize and contract leding to cervical canal distortion or obliteration and cervical incompetence.
  • Cervical incompetence can also result from tearing of the circular cervical muscularis without associated mucosal damage, and poor healing following surgical closure of a cervical laceration if the submucosal tissue becomes trapped between the edges of the muscularis.
  • Excessive cervical stretching during parturition can cause total disruption of the muscularis and of the vaginal/cervical mucosal layers leading to a wedge-shape defect in the body of the cervix, with the base at the external os.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Prevention

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Epstein K L (2010)Diagnosing the 'hidden' consequences of cervical trauma.Equine Vet Educ22(11), 564-565 Wiley Online Library.
  • Bracher V, Mathias S & Allen W R (1992)Videoendoscopic evaluation of the mare's uterus - II. Findings in subfertile mares.Equine Vet J24(4) 279-284 PubMed.
  • Brown J S, Varner D D, Hinrichs K & Kenney R M (1984)Surgical repair of the lacerated cervix in the mare.Theriogenology22(4), 351-359 PubMed.

Other sources of information

  • O'Leary J M & Rodgerson D J (2009)How to Repair Cervical Tears Using a Trendelenburg Type Positioning.In:ProcAAEP Congress. pp 269-271.
  • Samper, Pycock J F & McKinnon A O (2007)Cervical Tears.In:Current Therapy in Equine Reproduction.pp 130-133.
  • Aanes W A (1993)Cervical Lacerations.In:Equine Reproduction.Eds: McKinnon A O & Voss J L. Lea & Febiger, Philadelphia.


ADDED