Difference between revisions of "Recto-Vaginal Fistulae"

Latest revision as of 17:59, 31 July 2012

Introduction

A recto-vaginal fistula in mares can be caused during foaling by the foot-nape posture.

This occurs when the foal is presented with the legs forward without the head. This posture is possible in the mare due to the long limbs and slim head of the foal.

The presence of the foot-nape posture coupled with severe non-productive straining by the mare may cause the formation of a rectovaginal fistula or eventually a third degree perineal laceration. In these cases both the dorsal vaginal wall and rectum are penetrated by the foal's foot directed dorsally by the transverse fold between vagina and vestibule.

Recto-Vaginal fistulae can also be congenital.

Signalment

Recto-vaginal fistulae are most common in primiparous mares. They are generally caused by a combination of poor alignment of the foal and excessive straining by the mare.

Treatment

The mare should be kept on her feet and walked around as this can decrease straining efforts. An epidural should be administered to prevent straining. The foal should then be repositioned by forcefully repelling it and if possible lifting the foreleg(s) and placing them under the head. Lubricant and snares may be required to achieve this. If repositioning is unsuccessful but the foal is still alive an incision into the perineum can be made prior to any further attempts to remove the fetus. If the foal is dead this procedure is not necessary and instead partial fetotomy should be performed. This is achieved by sectioning the feet at the radius before removing the remainder of the foal. The damaged tissue should be assessed for bleeding, and any devitalised tissue cut away. As for perineal lacerations, there is usually extensive bruising and laceration of the tissue, therefore repair should be delayed until bruising has subsided and granulation tissue has formed, usually a minimum of 6–8 weeks after foaling or when the foal is weaned.

Prognosis

Prognosis is good as the normal anatomy of both the rectal and vaginal wall is restored following surgical repair. It should be noted that the function of the anal sphincter may not completely return to normal.

Recto-Vaginal Fistulae Learning Resources
Flashcards Test your knowledge using flashcard type questions	Equine Reproduction and Stud Medicine Q&A 04

References

Merck & Co (2009) The Merck Veterinary Manual (Ninth Edition), Merial

McGladdery, A (2001) Dystocia and post-partum complications in the mare In Practice 2001 23: 74-8

Pycock, JF (1997) Self-Assessment Colour Review Equine Reproduction and Stud Medicine Manson

Endell Equine Hospital Foaling Information accessed August 2, 2011

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+{{OpenPagesTop}}
 ==Introduction==
-A recto-vaginal fistula can be caused during foaling by the so-called '''foot-nape posture'''.
+A recto-vaginal fistula in mares can be caused during foaling by the '''foot-nape posture'''.
-This occurs when the '''foal''' is presented with the '''legs forward''' '''without the head'''. The long limbs and relatively slender head of the foal make this posture feasible in the mare. The foot of the foal is directed dorsally by the transverse fold between vagina and vestibule. After a long period of severe non-productive straining, a foot-nape posture may lead to a '''rectovaginal fistula''' or eventually a '''third degree perineal laceration'''. In these cases both the dorsal vaginal wall and rectum are penetrated.
+This occurs when the '''foal''' is presented with the '''legs forward''' '''without the head'''. This posture is possible in the mare due to  the long limbs and slim head of the foal.
+The presence of the foot-nape posture coupled with severe non-productive straining by the mare may cause the formation of a  '''rectovaginal fistula''' or eventually a '''third degree [[Perineal Laceration - Horse|perineal laceration]]'''. In these cases both the dorsal vaginal wall and rectum are penetrated by the foal's foot directed dorsally by the transverse fold between vagina and vestibule.
 Recto-Vaginal fistulae can also be congenital.
 ==Signalment==
-It is most common in '''primiparous''' mares. It is generally caused by a combination of '''poor alignment''' of the foal and '''excessive straining''' by the mare.
+Recto-vaginal fistulae are most common in '''primiparous''' mares. They are generally caused by a combination of '''poor alignment''' of the foal and '''excessive straining''' by the mare.
 ==Treatment==
-If possible, it is important to keep the animal on her '''feet''', and quiet walking may decrease straining efforts. Reposition is first attempted after '''epidural anaesthesia''' (which prevents straining). The foal is '''forcefully repelled''' and if possible the '''foreleg(s)''' are '''lifted''' and '''placed underneath the head'''. Lubricant and snares may be required to achieve this. If this is not successful and the foal is still alive, '''incision of the perineum''' may be necessary before extraction of the fetus. If the fetus is '''dead''' a quick partial '''fetotomy''' is indicated. The feet can be sectioned in the radius after which a careful extraction will be possible. The traumatised tissue should be checked for '''bleeding''', and '''devitalised tissue removed'''. '''Final repair''' of the perineal laceration may be best delayed until '''weaning of the foal''', i.e. at least a few months after parturition.
+The mare should be kept on her '''feet''' and walked around as this can decrease straining efforts. An epidural should be administered to prevent straining. The foal should then be repositioned by '''forcefully repelling it''' and if possible '''lifting the foreleg(s)''' and '''placing them under the head'''. '''Lubricant''' and '''snares''' may be required to achieve this. If repositioning is unsuccessful but the foal is still alive an '''incision into the perineum''' can be made prior to any further attempts to remove the fetus. If the foal is dead this procedure is not necessary and instead partial '''fetotomy''' should be performed. This is achieved by sectioning the feet at the radius before removing the remainder of the foal. The damaged tissue should be assessed for '''bleeding''', and any '''devitalised tissue''' cut away. As for [[Perineal Laceration - Horse|perineal lacerations]], there is usually extensive bruising and laceration of the tissue, therefore repair should be delayed until bruising has subsided and '''granulation tissue''' has formed, usually a minimum of '''6–8 weeks''' after foaling or when the foal is '''weaned'''.
 ==Prognosis==
-Although the function of the anal sphincter is not always completely restored, the prognosis for surgical restoration of the rectal and vaginal wall a few months after birth is '''good'''.
+Prognosis is '''good''' as the normal anatomy of both the rectal and vaginal wall is restored following surgical repair. It should be noted that the function of the anal sphincter may not completely return to normal.
+{{Learning
+|flashcards = [[Equine Reproduction and Stud Medicine Q&A 04]]
+}}
 ==References==
-[http://www.endellequinehospital.co.uk/news-a-information/health-care/foaling-mare.html/ Endell Equine Hospital Foaling Information]
+Merck & Co (2009) '''The Merck Veterinary Manual''' (Ninth Edition), ''Merial''
-Merck & Co (2009) '''The Merck Veterinary Manual''' (Ninth Edition), ''Merial''
+McGladdery, A (2001) '''Dystocia and post-partum complications in the mare''' ''In Practice 2001 23: 74-8''
 Pycock, JF (1997) '''Self-Assessment Colour Review Equine Reproduction and Stud Medicine''' ''Manson''
-[[Category:To Do - Siobhan Brade]]
+[http://www.endellequinehospital.co.uk/news-a-information/health-care/foaling-mare.html Endell Equine Hospital Foaling Information] accessed August 2, 2011
+{{review}}
+{{OpenPages}}
+[[Category:Reproductive Diseases - Horse]]
+[[Category:Expert Review - Horse]]