Anal atresia is also known as atresia and anorectalism. It is a common congenital abnormality of the digestive tract, accounting for 1/1500 to 1/5000 of newborns, more in males than females. It is often combined with other malformations, accounting for about 41.6% of cases. The etiology of this disease is unclear. The anus, anal canal, and lower rectum are atretic after birth, and the anus is not visible externally or only a small fistula is visible. The main clinical treatment is surgery. 1. Etiology Due to impaired development of the primitive anus, the anal canal is not recessed inward to form the anal canal. The rectum is essentially normal in development, with its blind end at the edge of the urethral bulbospongiosus, or near the lower end of the vagina, and the puborectalis muscle wrapping around the distal rectum. The perineum is often hypoplastic and flat, and the anal area is covered by intact skin. It may be combined with urethral bulb, lower vaginal segment or vestibular fistula. 2. Clinical manifestations The child is born without meconium discharge and soon develops symptoms of gastrointestinal obstruction such as vomiting and abdominal distention. On local examination, the perineum is flat in the center and the anal area is partially covered by skin. In some cases, there is a small concavity with obvious pigmentation and radiating wrinkles, and a contraction response of the ring muscle is seen in response to stimulation of the area. When the infant cries or holds his breath, there is a protrusion in the center of the perineum, and there is a percussion sensation when the finger is placed in this area, and a drum sound when the infant is placed in a hip-high, head-low position and percussed at the anus. There is no meconium discharge after birth, the anal area is covered with skin, and there is percussion in the anal area when crying. On the inverted X-ray lateral film, the end of the rectum is located at the pubococcygeal line or slightly below it, and the blind end of the rectum is about 1.5 cm from the skin of the anal area as measured by ultrasound and puncture method, which is low anal atresia, and more than 2 cm is high anal atresia. 4.Treatment After diagnosis, early surgery should be performed, generally perineal anoplasty, sacral perineal anoplasty can also be used, and high anal atresia is operated with minimally invasive methods. (1) Incision An X-shaped incision of about 1.5 cm is made in the middle of the perineum or in the middle of the circumferential constriction area, where the skin is cut and the four flaps are turned over and the circumferential external sphincter fibers are visible underneath. (2) Search for the blind end of the rectum The blind end of the rectum can be found by bluntly separating the soft tissues with ant-type vascular forceps through the middle of the sphincter muscle to the deeper layers, and two thick silk threads are threaded in the muscle layer of the blind end for traction. Because the blind end of the rectum is located in the puborectalis muscle ring, it should be separated upward against the intestinal wall. The blind end of the rectum should be separated by about 3 cm so that the rectum can be pulled loosely to the anal opening. The free rectum must be of sufficient length, and if it is not sufficiently free and forced to pull down the suture, the intestinal wall is very likely to retract after surgery, resulting in scar stenosis. The urethra, vagina and rectal wall should also be avoided during separation. (3) Rectal incision A cross-shaped incision is made at the blind end of the rectum, and the meconium is sucked up with a suction device or allowed to flow out naturally and swabbed. Pay attention to the protection of the wound and try to avoid contamination. If contamination occurs, it should be carefully flushed with saline. (4) Anastomosis fixation The blind end of the rectum is fixed with the surrounding soft tissue for several stitches, and the intestinal wall and perianal skin are intermittently sutured with fine silk or intestinal thread for 8 to 12 stitches. Note that the intestinal wall and the skin flap should be crossed over so that the scar is not in one plane after healing. Anal dilation should be started about 15 days after surgery to prevent anal stenosis.