Pediatric surgeons do not monitor at the fundamental researches on the anatomy, histology and physiology of the anorectal area. Diagnostic and therapeutic measures at anorectal malformations are based on misconceptions, leading to misdiagnosis and inappropriate treatment of these patients. It is enough to look at the latest publications on the subject at Medline, to notice the lack of basic knowledge. Here is a typical example:
In the article Dhar et al. shown an invertogram of a 1-day-old male neonate "suggesting a high anorectal malformation" (Figure 1 and my scheme to it) .
On radiograph there are symptoms of the digestive tract obstruction. The anorectal zone is typical for a normal newborn. The distal contour of the rectum is located on the pubococcygeal line (P-C) line. Gas does not pass the caudal of this line, because of the anal canal contraction. An evidence of this is the cone-shaped protrusion of gas caused by the relaxation of the internal anal sphincter and contraction of the puborectalis muscle. The movement of stool and gas through the colon occurs by the movement of peristaltic wave, so performing invertogram or radiograph with the elevated pelvis does not make sense.
Functional X-ray diagnosis in newborns with anorectal malformation:
The child is lying on his side. Radiologist stands near the head. One of his hands is on the back and other one is on the abdomen. When the abdomen is compressed the baby stars crying, which causes an increase in intra-abdominal pressure. When it rises above the threshold level, the anal canal opens and the gas penetrates into it, showing the true caudal contour.
Pediatric surgeons do not understand the physiological basis of high-pressure distal colostogram. The high (threshold) pressure is required for the disclosure of the anal canal, what is erroneously estimated as the descending perineum . In most cases, urethral fistula (souste) is located in the distal part of the functioning anal canal, i.e. it is of a low type malformation. In some patients this compound represented by the cord. In other cases, a hole is so narrow that penetration of contrast agent into urethra, and hence the liquid feces, may be only under high pressure (Figure 2, 3). After the perineal perforation procedure this hole during the fecal retention phase is protected from high pressure, because the anal canal is closed and reliably closes this souste.
During defecation the strong peristaltic wave causes a rise in the rectal pressure. The peristaltic wave does not pass to the anal canal. The anal canal widely opens as a result of the contraction of the levator ani muscle and therefore the pressure in it is low.
Thus, at very narrow fistula opening there is no conditions (not high pressure) for penetration of the feces from the anal canal into the urinary tract. If a boy with ARM has no meconium in his urine, it is not necessary to cut off the anal canal from the urethra, and remove it in the guise of the fistula.
Figure 2. Augmented pressure colostogram in the boy with low urethral fistula (asterisk) between the anal canal and urethra. A. The scheme of the defect; B. The scheme of the perineal perforation procedure [3, 4].
Figure 3. MRI with augmented pressure colostogram in the boy with the low urethral fistula (arrow). A. During anal canal opening. B. The scheme of the defect during the anal canal closing.
The operation of forming the anus in patients with perineal and vestibular fistula should preferably be done a few months after birth. The ectopic anus is rarely wide enough to ensure normal defecation. In the narrow anus it is very important to prevent the development of secondary changes: megarectum, damage of the pelvic floor muscles. For this purpose it is necessary to cut the annulus at two locations on the diameter of the ring.
The operation of forming anus (Figure 4) [3,4]. The cruciform incision in the skin of the anal fossa is done. The subcutaneous portion of the external anal sphincter is bared. Its inner lumen is stretched so as to conduct the lower plate of the device with a diameter of 0.8-1.2 cm through its ring. Then the upper plate is entered into the anal canal through the ectopic anus. The device is tightened down to an emphasis and the bottom plate is screwed through the ring in the external sphincter until it stops with the top plate. The device is removed through the week. After 2 weeks, you can start the bougienage of the created anus. When its diameter reaches the desired size you need to hermetically sew up the ectopic anus, avoiding getting into the wound mucosa of the anal canal.
Figure 4. The explanation in the text.
Faith in the false assumptions prevails over scientific facts. Statistical studies in recent years show a significant percentage of the severe complications requiring reoperations. My experience suggests that full recovery is possible.
Dhar M1, Singh RB1, Gupta BK1, Pai VK1. Peri-operative management of a neonate with tracheo-oesophageal fistula and anorectal malformation: Survival of the fittest. Indian J Anaesth. 2016 Oct;60(10):788-789.
Levin MD. The pathophysiology of anorectal malformations. From a new concept to a new treatment. http://www.anorectalmalformations.com/