Anal deformity

Introduction There are many types of anal malformations, and the position of the rectal blind end and the fistula are different. Its incidence rate in the newborn is 1:1500 ~ 5000, accounting for the first place in the digestive tract malformation. More men than women, high malformations accounted for about 50% of men and 20% of women. The incidence of various fistulas is 90% in women and 70% in men. The incidence of other congenital malformations is about 30-50%, and often multiple deformities. Family history is rare, only 1%. There is heredity, but the genetic method is still inconclusive.

Cause

The occurrence of anal malformation is the result of an obstacle in the development of the embryo, and the male and female are basically the same, only the anatomical difference. As a result of the cloaca separation process, the urogenital sinus and the anorectal sinus communicate with each other to form a high or intermediate malformation, and various anorectal hypoplasia and fistulas between the rectum and the urethra or vagina occur. The result of anal posterior movement disorder and perineal dysplasia constitutes a low position deformity, anal skin spasm, anal vestibular fistula, anal stenosis and the like.

an examination

Anal malformation

1. X-ray findings of the abdominal position flat film showed low colonic obstruction. In the photos of the lateral and anterior and posterior positions of the barium enema, the typical sacral segment and the dilated bowel segment can be seen. The function of sputum excretion is poor. After 24 hours, there are still sputum retention. If the sputum is not washed out in time, vermiculite can be formed. In the case of enteritis, the intestinal wall of the dilated bowel is serrated, and the expansion of the intestine in the neonatal period is more than half a month after birth. If you still cannot be diagnosed, do the following.

Anal malformation

2, biopsy taken from the anus more than 4cm above the rectal wall of the rectal wall and a small layer of muscle layer, check the number of ganglion cells, the lack of ganglion cells in children with megacolon.

Anal malformation

3, anorectal manometry to determine the reflex pressure changes of the rectum and anal sphincter, can diagnose the congenital megacolon and identify constipation caused by other causes. In normal children and functional constipation, when the rectum is stimulated by swelling, the internal sphincter immediately undergoes reflex relaxation and the pressure drops. The internal sphincter of the congenital megacolon not only does not relax, but also causes obvious contraction and increases the pressure. This method can sometimes produce false positive results in newborns within 10 days.

Anal malformation

4, rectal mucosal histochemical examination method is based on the submucosal and myometrial ganglion cells lacking hyperplasia, hypertrophic parasympathetic preganglionic fibers continue to release a large amount of acetylcholine and choline enzyme, chemically determined Both the number and activity are 5-6 times higher than normal children, which is helpful for the diagnosis of Hirschsprung's disease and can be used for newborns.

Differential diagnosis

1, high malformation

(1) Anorectal hypoplasia:

1 rectal prostatic urethra fistula: fistula opening in the posterior urethra, no anal internal sphincter, external sphincter is not obvious, blind end is located on the PC line.

2 innocent: there may be a fiber-optic band connection between the blind end and the urethra, no anal internal sphincter, only external sphincter marks, blind end flat or higher than PC line.

(2) rectal atresia: the rectal blind end stops at different heights, the anus and anal canal are normal, there are anal internal and external sphincter and levator ani muscle, and maintain normal relationship with the anal canal.

2, the middle position deformity

(1) rectal urethral bulbar fistula: the rectal blind end of the rectum is located above the corpus cavernosum muscle, the puborectalis muscle surrounds the rectum blind end fistula, the anal internal sphincter is absent, and the rectal blind end is located between the PC line and the I line. .

(2) anal hypoplasia, innocent: the rectal blind end of the urethral bulb above the cavernosal muscle, the puborectalis muscle surrounds the rectal blind end. The anal internal sphincter is absent, the external sphincter only shows traces, and the rectal blind end is located between the PC line and the I line.

3, low malformation

(1) Anal skin spasm: The fistula is open to the anus to any part of the midline of the back of the urethra, and the scrotum is mostly. The anal canal is lobed and the fistula is covered by a thin skin flap. The puborectal muscle is normal.

(2) Anal stenosis: the anus and internal and external sphincters are normal.

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