pISSN 1598-298XJ Vet Clin 30(5) : 376-379 (2013)

376

Surgical Correction of Congenital Type III Atresia ani with

Rectovaginal Fistula in a Cat

Minkyung Kim**, Yong-Hyun Hwang*,**, Woo Choi* and Jae-Hoon Lee**1

*Pet’s All Animal hospital, Changwon-si 631-712, Korea

**Institute of animal medicine, Veterinary Surgery,

College of Veterinary Medicine Gyeongsang National University, Jinju 660-701, Korea

(Accepted: October 23, 2013)

Abstract : A four-week-old female Scottish Fold cat weighting 0.6 kg was admitted for vaccination. During the physicalexamination, the liquid feces were observed from the vulva and the anus was imperforate. The location of a narrowfistula and distended colon were identified on the contrast radiography. Definitive diagnosis was made as type III atresiaani with rectovaginal fistula. Anal reconstruction and ligation of the fistula were successfully undertaken to treat atresiaani. After surgery, the cat was treated with lactulose and a special diet consisting of high fiber was fed to increasedigestibility. The cat was able to control defecation after 2 weeks post-operation. There was no complication for 8months after surgery.

Key words : Atresia ani, rectovaginal fistula, surgical correction, cat.

Introduction

Atresia ani (AA) is a congenital defect of the anorectum,

resulting in anal canal closure and / or abnormal rouging of

feces. AA develops during formation of the embryo when

normal separation of the primitive cloaca into the rectum and

urogenital sinus by the urerectal fold is not completed, and

imperforate anus results from failure of anal membrane open-

ing after anal development in the fetus (1,12). According to a

review in the Veterinary Medical Database, AA accounts for

0.007% of cases in dogs with females more likely to be

affected than males (female: male = 1.79: 1) (12). In cats,

females are more commonly affected than males (3,9-11).

The most common classification of AA similar to that used

in humans has been described in dogs and cats (2,4,12). This

classification includes four basic anatomical types (2). Type I

classification denotes anal stenosis without an imperforate

anus. Animals with type II anomalies have a persistence of

the anal membrane, and the rectum ends immediately cranial

to the imperforate anus as a blind pouch. In type III, the anus

is also closed, but the blind end of the rectum is situated far-

ther cranially. In type IV, the anus and terminal ends as a

blind pouch within the pelvic canal.

The prognosis for atresia ani is poor and although surgical

correction may be attempted, affected animals are young,

small and typically poor in body condition and thus the sur-

gical mortality rate is high (2).

In this kitten attempts were made to surgically correct the

anatomic malformations. The purpose of this report is to

describe the clinical signs, radiographic findings, surgical

treatment of type III atresia ani in a Scottish Fold cat.

Case

A four-week-old female Scottish Fold cat weighing 0.6 kg

in good clinical condition showing good signs of activity was

admitted for vaccination. During the physical examination,

abdominal distension was revealed and liquid feces were

observed from the vulva and the anus was imperforate (Fig

1). A complete blood count and biochemical panels were

within reference ranges, except for mild lymphocytosis.

The location of a narrow fistula and distended colon were

identified in contrast radiography (Fig 2) using iohexol (Omi-

paque, Amersham health, Cork, Ireland). Definitive diagnosis

was made as type III atresia ani with ureterorectal fistula.

The cat received cefazolin, 30 mg/kg IV (CEFAZOLIN,

Chong Hun Dang) and atropine 0.04 mg/kg SC (Jaeil Pha-

maco, South Korea) before the induction of anesthesia and

was premedicated with medetomidine, 0.02 mg/kg IM (Domi-

tor®, Orion PharmaCo., Finland). Anesthesia was induced

with propofol, 6 mg/kg (Anepol, Hana Pharm Co., Ltd.,

Korea), a size 2.5-cuffed endotracheal tube was inserted and

1.5% isoflurane (Forane, Rhodia Organique Fine Ltd., Korea)

and oxygen (approximately 1.5 L/min) were added to the

room air. The cat was aseptically prepared and placed in ven-

tral recumbency with the elevation of the anus and rigid sta-

1Corresponding author.E-mail : jh1000@gnu.ac.kr

Surgical Correction of Congenital Type III Atresia ani with Rectovaginal Fistula in a Cat 377

bility of the body was secured with a vacuum bean bag. A

skin incision was made in the skin over the anal dimple. The

rectal pouch and ureterorectal fistula were identified through

the incision. The affected rectal portion was excised and the

fistula tract was ligated with 4-0 monofilament absorbable

suture material. The resection of the terminal colon using an

anal approach was needed because the rectal pouch was

located more than 1 cm away from the anal dimple. The ter-

minal part of the rectum was sutured with the skin at the

level of the external anal sphincter (Fig 2). After surgery, the

cat was treated with lactulose and a special diet consisting of

high fiber (w/d®, Hill’s prescription diet) was fed to increase

digestibility.

The cat was able to control defecation after 2 weeks post-

operation. At the follow-up evaluation obtained by telephone

until now (for 8 months from operation), defecation was nor-

mal without complications.

Discussion

Many cases of AA are not recognized until weaning, when

tenesmus and abdominal distension become more noticeable.

Fig 1. Right lateral radiographic view. Images were obtained after intravaginal administration of contrast medium (iohexol). (A) The

flow of the contrast from the vagina to the rectum denoting the rectovaginal communication (arrow). (B) The distance between the

blind rectal pouch and the perineal skin was measured as 1.2 cm (double-head arrow).

Fig 2. (A) Atresia ani (arrow) and vulva (arrowhead) are noted. (B) The rectal pouch is identified through the skin incision. (C) Rec-

tovaginal fistula (arrow) was conformed and was ligated using synthetic absorbable material. (D) The rectal mucosa of the dog was

sutured to the skin using a simple interrupted pattern.

378 Minkyung Kim, Yong-Hyun Hwang, Woo Choi and Jae-Hoon Lee

Most affected animals described in the literatures of veteri-

nary medicine have been female. Many have had concomi-

tant rectovaginal fistula (3,5,8).

Initial diagnosis of AA was made on the basis of the

results of the physical examination and the history of tenes-

mus and perivular soiling.

Abdominal radiography is useful in AA anatomic typing

and in ruling out colonic distention, which may lead to mega-

colon that affects management and prognosis. In females,

vaginography is helpful in determining the presence of a fis-

tula and the location of a terminal rectum (2,6,9,11).

Although type I cases can be applied to non-surgical man-

agement, surgical correction is considered the treatment for

other types of AA (3,10). In this report, the cat was con-

firmed to have a type III AA with rectovaginal fistula. The

fistula was isolated via a vertical incision around the anal

dimple, and was ligated. The sutures were made along the

center of the anal sphincter. We assumed that the good prog-

nosis in this case would be related with the external sphinc-

ter muscle relatively intact.

In another technique, the fistulous tract can be preserved,

isolated, mobilized through the anus and sutured with the

skin at the level of the external anal sphincter (7). This pro-

cedure can also be modified to be performed through an epi-

siotomy incision (6). Because it is believed that portions of

the internal anal sphincter are preserved within the rectovag-

inal communication in humans and the tissue used here may

also reduce the tension along the suture line, some investiga-

tors have advocated the technique of reconstruction with the

rectovaginal fistula (6,7). However, this procedure is not

applicable to males (3). In addition, concomitant or subse-

quent neutering of females is necessary with this technique

because of the rectal swelling during the estrus in female dogs

(6). In another report (3), one puppy whose rectovaginal fis-

tula was preserved in the procedure needed to have balloon

dilation twice because of a stenosis within the fistula.

Complications after surgical corrections include tenesmus,

fecal incontinence, wound dehiscence, megacolon and rectal

prolapse (2,3,7). Fecal incontinence is a common complica-

tion after surgery that may be transient, intermittent or per-

manent which may be related to the congenital absence of a

functional external anal sphincter or a surgical trauma to the

sphincter muscle innervation (2,3,7,12). In this case, fecal

incontinence was shown for 2 weeks after surgery. As we

mentioned above, the sphincter muscle may be well reserved,

the minimal trauma to the sphincter muscle innervation may

be one of reason for the good prognosis.

In the case reported here, anal reconstruction was success-

fully undertaken to treat atresia ani. Although the rectum was

sutured slightly to the right side, the sutures were placed in

the center of the external sphincter muscle. The cat had fecal

incontinence for approximately 10 days after surgery and

sphincter function had returned at 2 weeks postoperatively.

And defecation was normal without complications for 8

months after surgery.

References

1. Arey LB. Developmental anatomy. In: A textbook and la-

boratory manual of embryology. 7th ed. Philadelphia: WB

Sanunders. 1965: 308-314.

2. Aronson L. Rectum and Anus. In: Slatter D, ed. Textbook of

small animal surgery 3rd ed. Philadelphia: Saunders. 2002:

684-685.

3. Ellison GW, Papazoglou LG. Long-term results of surgery

for atresia ani with or without anogenital malformations in

puppies and a kitten: 12 cases (1983-2010). JAVMA 2012;

240: 186-192.

4. Golighter J, Duthie H, Nixon H. Surgery of the anus rectum

and colon. 5th ed. London: Bailliere Tindall. 1984.

5. Louw GJ, van Schouwenburg SJ. The surgical repair of

atresia ani in a Dobermann bitch. J S Afr Vet Assoc. 1982;

53: 119-120.

6. Mahler S, Williams G. Preservation of the fistula for recon-

struction of the anal canal and the anus in atresia ani and

rectovestibular fistula in 2 dogs. Vet Surg 2005; 34: 148-152.

7. Prassinos NN, Papazoglou LG, Adamama-Moraitou KK,

Galatos AD, Gouletsou P, Rallis TS. Congenital anorectal

abnormalities in six dogs. Vet Rec 2003; 153: 81-85.

8. Rawlings CA, Capps WF, Jr. Rectovaginal fistula and im-

perforate anus in a dog. JAVMA 1971; 159: 320-326.

9. Suess RP, Jr., Martin RA, Moon ML, Dallman MJ.

Rectovaginal fistula with atresia ani in three kittens. Cornell

Vet 1992; 82: 141-153.

10. Tomsa K, Major A, Glaus TM. Treatment of atresia ani type

I by balloon dilatation in 5 kittens and one puppy. Schweiz

Arch Tierheilkd 2011; 153: 277-280.

11. Tsioli V, Papazoglou LG, Anagnostou T, Kouti V, Papado-

poulou P. Use of a temporary incontinent end-on colostomy

in a cat for the management of rectocutaneous fistulas

associated with atresia ani. J Feline Med Surg 2009; 11:

1011-1014.

12. Vianna ML, Tobias KM. Atresia ani in the dog: a retro-

spective study. JAVMA 2005; 41: 317-322.

Surgical Correction of Congenital Type III Atresia ani with Rectovaginal Fistula in a Cat 379

고양이의 직장질루가 병발한 Type III 선천성 항문무형성증의 수술적 교정

김민경**·황용현*,**·최우*·이재훈**

1

*펫츠올 동물병원, **경상대학교 수의과대학

요 약 : 4주령의 0.6 kg 암컷 스콧티쉬 폴드 고양이가 예방 접종을 위해 내원하였다. 신체 검사에서 수양성 분변이 질

에서 나오는 것이 확인 되었고 항문은 폐쇄되어 있었다. 방사선 양성 조영 검사에서 직장질루, 확장된 결장이 확인 되

었다. 영상 검사에 기초하여 Type III 의 항문 무형성과 직장 질루가 병발한 것으로 최종 진단 하였다. 수술적인 직장

질루의 폐쇄와 항문의 재건이 실시되었다. 수술 후 소화능력을 향상시키기 위해서 락툴로즈와 식이요법을 실시 하였

고, 고양이는 수술 후 2주에 배변 조절이 가능해졌으며, 8개월 후 추적조사에서 합병증 없이 배변조절 상태가 유지 되

었다.

주요어 :항문 무형성, 직장질루, 수술적 교정, 고양이